]> git.ipfire.org Git - thirdparty/git.git/commitdiff
Merge remote-tracking branch 'ko/maint' into jc/diff-index-quick-exit-early
authorJunio C Hamano <gitster@pobox.com>
Tue, 31 May 2011 17:57:32 +0000 (10:57 -0700)
committerJunio C Hamano <gitster@pobox.com>
Tue, 31 May 2011 17:57:32 +0000 (10:57 -0700)
* ko/maint: (4352 commits)
  git-submodule.sh: separate parens by a space to avoid confusing some shells
  Documentation/technical/api-diff.txt: correct name of diff_unmerge()
  read_gitfile_gently: use ssize_t to hold read result
  remove tests of always-false condition
  rerere.c: diagnose a corrupt MERGE_RR when hitting EOF between TAB and '\0'
  Git 1.7.5.3
  init/clone: remove short option -L and document --separate-git-dir
  do not read beyond end of malloc'd buffer
  git-svn: Fix git svn log --show-commit
  Git 1.7.5.2
  provide a copy of the LGPLv2.1
  test core.gitproxy configuration
  copy_gecos: fix not adding nlen to len when processing "&"
  Update draft release notes to 1.7.5.2
  Documentation/git-fsck.txt: fix typo: unreadable -> unreachable
  send-pack: avoid deadlock on git:// push with failed pack-objects
  connect: let callers know if connection is a socket
  connect: treat generic proxy processes like ssh processes
  sideband_demux(): fix decl-after-stmt
  t3503: test cherry picking and reverting root commits
  ...

Conflicts:
diff.c

1  2 
diff-lib.c
diff.c
diff.h
t/t4040-whitespace-status.sh
tree-diff.c

diff --combined diff-lib.c
index 869d8f0e77832385c6047dce48e28dcc91171fb3,3b5f2242a597ff1b44a3af6be72cb14e6e0d5455..9c29293bbc05d175ba13338813e8532c7ad677cf
@@@ -10,6 -10,7 +10,7 @@@
  #include "cache-tree.h"
  #include "unpack-trees.h"
  #include "refs.h"
+ #include "submodule.h"
  
  /*
   * diff-files
@@@ -54,6 -55,33 +55,33 @@@ static int check_removed(const struct c
        return 0;
  }
  
+ /*
+  * Has a file changed or has a submodule new commits or a dirty work tree?
+  *
+  * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
+  * option is set, the caller does not only want to know if a submodule is
+  * modified at all but wants to know all the conditions that are met (new
+  * commits, untracked content and/or modified content).
+  */
+ static int match_stat_with_submodule(struct diff_options *diffopt,
+                                     struct cache_entry *ce, struct stat *st,
+                                     unsigned ce_option, unsigned *dirty_submodule)
+ {
+       int changed = ce_match_stat(ce, st, ce_option);
+       if (S_ISGITLINK(ce->ce_mode)) {
+               unsigned orig_flags = diffopt->flags;
+               if (!DIFF_OPT_TST(diffopt, OVERRIDE_SUBMODULE_CONFIG))
+                       set_diffopt_flags_from_submodule_config(diffopt, ce->name);
+               if (DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES))
+                       changed = 0;
+               else if (!DIFF_OPT_TST(diffopt, IGNORE_DIRTY_SUBMODULES)
+                   && (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES)))
+                       *dirty_submodule = is_submodule_modified(ce->name, DIFF_OPT_TST(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES));
+               diffopt->flags = orig_flags;
+       }
+       return changed;
+ }
  int run_diff_files(struct rev_info *revs, unsigned int option)
  {
        int entries, i;
                unsigned int oldmode, newmode;
                struct cache_entry *ce = active_cache[i];
                int changed;
+               unsigned dirty_submodule = 0;
  
 -              if (DIFF_OPT_TST(&revs->diffopt, QUICK) &&
 -                  !revs->diffopt.filter &&
 -                  DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
 +              if (diff_can_quit_early(&revs->diffopt))
                        break;
  
-               if (!ce_path_match(ce, revs->prune_data))
+               if (!ce_path_match(ce, &revs->prune_data))
                        continue;
  
                if (ce_stage(ce)) {
                        struct combine_diff_path *dpath;
+                       struct diff_filepair *pair;
+                       unsigned int wt_mode = 0;
                        int num_compare_stages = 0;
                        size_t path_len;
  
  
                        changed = check_removed(ce, &st);
                        if (!changed)
-                               dpath->mode = ce_mode_from_stat(ce, st.st_mode);
+                               wt_mode = ce_mode_from_stat(ce, st.st_mode);
                        else {
                                if (changed < 0) {
                                        perror(ce->name);
                                }
                                if (silent_on_removed)
                                        continue;
+                               wt_mode = 0;
                        }
+                       dpath->mode = wt_mode;
  
                        while (i < entries) {
                                struct cache_entry *nce = active_cache[i];
                         * Show the diff for the 'ce' if we found the one
                         * from the desired stage.
                         */
-                       diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
+                       pair = diff_unmerge(&revs->diffopt, ce->name);
+                       if (wt_mode)
+                               pair->two->mode = wt_mode;
                        if (ce_stage(ce) != diff_unmerged_stage)
                                continue;
                }
  
-               if (ce_uptodate(ce))
+               if (ce_uptodate(ce) || ce_skip_worktree(ce))
                        continue;
  
-               changed = check_removed(ce, &st);
+               /* If CE_VALID is set, don't look at workdir for file removal */
+               changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
                if (changed) {
                        if (changed < 0) {
                                perror(ce->name);
                        if (silent_on_removed)
                                continue;
                        diff_addremove(&revs->diffopt, '-', ce->ce_mode,
-                                      ce->sha1, ce->name);
+                                      ce->sha1, ce->name, 0);
                        continue;
                }
-               changed = ce_match_stat(ce, &st, ce_option);
-               if (!changed) {
+               changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
+                                                   ce_option, &dirty_submodule);
+               if (!changed && !dirty_submodule) {
                        ce_mark_uptodate(ce);
                        if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
                                continue;
                newmode = ce_mode_from_stat(ce, st.st_mode);
                diff_change(&revs->diffopt, oldmode, newmode,
                            ce->sha1, (changed ? null_sha1 : ce->sha1),
-                           ce->name);
+                           ce->name, 0, dirty_submodule);
  
        }
        diffcore_std(&revs->diffopt);
  static void diff_index_show_file(struct rev_info *revs,
                                 const char *prefix,
                                 struct cache_entry *ce,
-                                const unsigned char *sha1, unsigned int mode)
+                                const unsigned char *sha1, unsigned int mode,
+                                unsigned dirty_submodule)
  {
        diff_addremove(&revs->diffopt, prefix[0], mode,
-                      sha1, ce->name);
+                      sha1, ce->name, dirty_submodule);
  }
  
  static int get_stat_data(struct cache_entry *ce,
                         const unsigned char **sha1p,
                         unsigned int *modep,
-                        int cached, int match_missing)
+                        int cached, int match_missing,
+                        unsigned *dirty_submodule, struct diff_options *diffopt)
  {
        const unsigned char *sha1 = ce->sha1;
        unsigned int mode = ce->ce_mode;
                        }
                        return -1;
                }
-               changed = ce_match_stat(ce, &st, 0);
+               changed = match_stat_with_submodule(diffopt, ce, &st,
+                                                   0, dirty_submodule);
                if (changed) {
                        mode = ce_mode_from_stat(ce, st.st_mode);
                        sha1 = null_sha1;
@@@ -245,15 -287,17 +285,17 @@@ static void show_new_file(struct rev_in
  {
        const unsigned char *sha1;
        unsigned int mode;
+       unsigned dirty_submodule = 0;
  
        /*
         * New file in the index: it might actually be different in
         * the working copy.
         */
-       if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
+       if (get_stat_data(new, &sha1, &mode, cached, match_missing,
+           &dirty_submodule, &revs->diffopt) < 0)
                return;
  
-       diff_index_show_file(revs, "+", new, sha1, mode);
+       diff_index_show_file(revs, "+", new, sha1, mode, dirty_submodule);
  }
  
  static int show_modified(struct rev_info *revs,
  {
        unsigned int mode, oldmode;
        const unsigned char *sha1;
+       unsigned dirty_submodule = 0;
  
-       if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
+       if (get_stat_data(new, &sha1, &mode, cached, match_missing,
+                         &dirty_submodule, &revs->diffopt) < 0) {
                if (report_missing)
                        diff_index_show_file(revs, "-", old,
-                                            old->sha1, old->ce_mode);
+                                            old->sha1, old->ce_mode, 0);
                return -1;
        }
  
        }
  
        oldmode = old->ce_mode;
-       if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
+       if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
            !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
                return 0;
  
        diff_change(&revs->diffopt, oldmode, mode,
-                   old->sha1, sha1, old->name);
+                   old->sha1, sha1, old->name, 0, dirty_submodule);
        return 0;
  }
  
- /*
-  * This turns all merge entries into "stage 3". That guarantees that
-  * when we read in the new tree (into "stage 1"), we won't lose sight
-  * of the fact that we had unmerged entries.
-  */
- static void mark_merge_entries(void)
- {
-       int i;
-       for (i = 0; i < active_nr; i++) {
-               struct cache_entry *ce = active_cache[i];
-               if (!ce_stage(ce))
-                       continue;
-               ce->ce_flags |= CE_STAGEMASK;
-       }
- }
  /*
   * This gets a mix of an existing index and a tree, one pathname entry
   * at a time. The index entry may be a single stage-0 one, but it could
@@@ -336,6 -366,9 +364,9 @@@ static void do_oneway_diff(struct unpac
        struct rev_info *revs = o->unpack_data;
        int match_missing, cached;
  
+       /* if the entry is not checked out, don't examine work tree */
+       cached = o->index_only ||
+               (idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
        /*
         * Backward compatibility wart - "diff-index -m" does
         * not mean "do not ignore merges", but "match_missing".
         * But with the revision flag parsing, that's found in
         * "!revs->ignore_merges".
         */
-       cached = o->index_only;
        match_missing = !revs->ignore_merges;
  
        if (cached && idx && ce_stage(idx)) {
-               if (tree)
-                       diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode, idx->sha1);
+               struct diff_filepair *pair;
+               pair = diff_unmerge(&revs->diffopt, idx->name);
+               fill_filespec(pair->one, idx->sha1, idx->ce_mode);
                return;
        }
  
         * Something removed from the tree?
         */
        if (!idx) {
-               diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode);
+               diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode, 0);
                return;
        }
  
        show_modified(revs, tree, idx, 1, cached, match_missing);
  }
  
- static inline void skip_same_name(struct cache_entry *ce, struct unpack_trees_options *o)
- {
-       int len = ce_namelen(ce);
-       const struct index_state *index = o->src_index;
-       while (o->pos < index->cache_nr) {
-               struct cache_entry *next = index->cache[o->pos];
-               if (len != ce_namelen(next))
-                       break;
-               if (memcmp(ce->name, next->name, len))
-                       break;
-               o->pos++;
-       }
- }
  /*
   * The unpack_trees() interface is designed for merging, so
   * the different source entries are designed primarily for
   * For diffing, the index is more important, and we only have a
   * single tree.
   *
-  * We're supposed to return how many index entries we want to skip.
+  * We're supposed to advance o->pos to skip what we have already processed.
   *
   * This wrapper makes it all more readable, and takes care of all
   * the fairly complex unpack_trees() semantic requirements, including
@@@ -408,9 -426,6 +424,6 @@@ static int oneway_diff(struct cache_ent
        struct cache_entry *tree = src[1];
        struct rev_info *revs = o->unpack_data;
  
-       if (idx && ce_stage(idx))
-               skip_same_name(idx, o);
        /*
         * Unpack-trees generates a DF/conflict entry if
         * there was a directory in the index and a tree
        if (tree == o->df_conflict_entry)
                tree = NULL;
  
-       if (ce_path_match(idx ? idx : tree, revs->prune_data))
+       if (ce_path_match(idx ? idx : tree, &revs->prune_data))
                do_oneway_diff(o, idx, tree);
  
        return 0;
@@@ -434,8 -449,6 +447,6 @@@ int run_diff_index(struct rev_info *rev
        struct unpack_trees_options opts;
        struct tree_desc t;
  
-       mark_merge_entries();
        ent = revs->pending.objects[0].item;
        tree_name = revs->pending.objects[0].name;
        tree = parse_tree_indirect(ent->sha1);
                exit(128);
  
        diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
+       diffcore_fix_diff_index(&revs->diffopt);
        diffcore_std(&revs->diffopt);
        diff_flush(&revs->diffopt);
        return 0;
@@@ -495,7 -509,7 +507,7 @@@ int do_diff_cache(const unsigned char *
        active_nr = dst - active_cache;
  
        init_revisions(&revs, NULL);
-       revs.prune_data = opt->paths;
+       init_pathspec(&revs.prune_data, opt->pathspec.raw);
        tree = parse_tree_indirect(tree_sha1);
        if (!tree)
                die("bad tree object %s", sha1_to_hex(tree_sha1));
  int index_differs_from(const char *def, int diff_flags)
  {
        struct rev_info rev;
+       struct setup_revision_opt opt;
  
        init_revisions(&rev, NULL);
-       setup_revisions(0, NULL, &rev, def);
+       memset(&opt, 0, sizeof(opt));
+       opt.def = def;
+       setup_revisions(0, NULL, &rev, &opt);
        DIFF_OPT_SET(&rev.diffopt, QUICK);
        DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
        rev.diffopt.flags |= diff_flags;
diff --combined diff.c
index ae6853fcf1ea1e10c1d8f6750f69b71a7a5e73b4,9a8012e362fe2bc08d4ecce21e68972579c3693b..7d1cdea310b95a93e63ab834475951d8c082c6c2
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -13,6 -13,8 +13,8 @@@
  #include "utf8.h"
  #include "userdiff.h"
  #include "sigchain.h"
+ #include "submodule.h"
+ #include "ll-merge.h"
  
  #ifdef NO_FAST_WORKING_DIRECTORY
  #define FAST_WORKING_DIRECTORY 0
  #endif
  
  static int diff_detect_rename_default;
- static int diff_rename_limit_default = 200;
+ static int diff_rename_limit_default = 400;
  static int diff_suppress_blank_empty;
  int diff_use_color_default = -1;
  static const char *diff_word_regex_cfg;
  static const char *external_diff_cmd_cfg;
  int diff_auto_refresh_index = 1;
  static int diff_mnemonic_prefix;
+ static int diff_no_prefix;
+ static struct diff_options default_diff_options;
  
  static char diff_colors[][COLOR_MAXLEN] = {
        GIT_COLOR_RESET,
        GIT_COLOR_GREEN,        /* NEW */
        GIT_COLOR_YELLOW,       /* COMMIT */
        GIT_COLOR_BG_RED,       /* WHITESPACE */
+       GIT_COLOR_NORMAL,       /* FUNCINFO */
  };
  
- static void diff_filespec_load_driver(struct diff_filespec *one);
- static char *run_textconv(const char *, struct diff_filespec *, size_t *);
  static int parse_diff_color_slot(const char *var, int ofs)
  {
        if (!strcasecmp(var+ofs, "plain"))
@@@ -59,7 -61,9 +61,9 @@@
                return DIFF_COMMIT;
        if (!strcasecmp(var+ofs, "whitespace"))
                return DIFF_WHITESPACE;
-       die("bad config variable '%s'", var);
+       if (!strcasecmp(var+ofs, "func"))
+               return DIFF_FUNCINFO;
+       return -1;
  }
  
  static int git_config_rename(const char *var, const char *value)
@@@ -95,11 -99,18 +99,18 @@@ int git_diff_ui_config(const char *var
                diff_mnemonic_prefix = git_config_bool(var, value);
                return 0;
        }
+       if (!strcmp(var, "diff.noprefix")) {
+               diff_no_prefix = git_config_bool(var, value);
+               return 0;
+       }
        if (!strcmp(var, "diff.external"))
                return git_config_string(&external_diff_cmd_cfg, var, value);
        if (!strcmp(var, "diff.wordregex"))
                return git_config_string(&diff_word_regex_cfg, var, value);
  
+       if (!strcmp(var, "diff.ignoresubmodules"))
+               handle_ignore_submodules_arg(&default_diff_options, value);
        return git_diff_basic_config(var, value, cb);
  }
  
@@@ -118,6 -129,8 +129,8 @@@ int git_diff_basic_config(const char *v
  
        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
                int slot = parse_diff_color_slot(var, 11);
+               if (slot < 0)
+                       return 0;
                if (!value)
                        return config_error_nonbool(var);
                color_parse(value, var, diff_colors[slot]);
                return 0;
        }
  
+       if (!prefixcmp(var, "submodule."))
+               return parse_submodule_config_option(var, value);
        return git_color_default_config(var, value, cb);
  }
  
@@@ -174,6 -190,252 +190,252 @@@ static struct diff_tempfile 
        char tmp_path[PATH_MAX];
  } diff_temp[2];
  
+ typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
+ struct emit_callback {
+       int color_diff;
+       unsigned ws_rule;
+       int blank_at_eof_in_preimage;
+       int blank_at_eof_in_postimage;
+       int lno_in_preimage;
+       int lno_in_postimage;
+       sane_truncate_fn truncate;
+       const char **label_path;
+       struct diff_words_data *diff_words;
+       struct diff_options *opt;
+       int *found_changesp;
+       struct strbuf *header;
+ };
+ static int count_lines(const char *data, int size)
+ {
+       int count, ch, completely_empty = 1, nl_just_seen = 0;
+       count = 0;
+       while (0 < size--) {
+               ch = *data++;
+               if (ch == '\n') {
+                       count++;
+                       nl_just_seen = 1;
+                       completely_empty = 0;
+               }
+               else {
+                       nl_just_seen = 0;
+                       completely_empty = 0;
+               }
+       }
+       if (completely_empty)
+               return 0;
+       if (!nl_just_seen)
+               count++; /* no trailing newline */
+       return count;
+ }
+ static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
+ {
+       if (!DIFF_FILE_VALID(one)) {
+               mf->ptr = (char *)""; /* does not matter */
+               mf->size = 0;
+               return 0;
+       }
+       else if (diff_populate_filespec(one, 0))
+               return -1;
+       mf->ptr = one->data;
+       mf->size = one->size;
+       return 0;
+ }
+ /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
+ static unsigned long diff_filespec_size(struct diff_filespec *one)
+ {
+       if (!DIFF_FILE_VALID(one))
+               return 0;
+       diff_populate_filespec(one, 1);
+       return one->size;
+ }
+ static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
+ {
+       char *ptr = mf->ptr;
+       long size = mf->size;
+       int cnt = 0;
+       if (!size)
+               return cnt;
+       ptr += size - 1; /* pointing at the very end */
+       if (*ptr != '\n')
+               ; /* incomplete line */
+       else
+               ptr--; /* skip the last LF */
+       while (mf->ptr < ptr) {
+               char *prev_eol;
+               for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
+                       if (*prev_eol == '\n')
+                               break;
+               if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
+                       break;
+               cnt++;
+               ptr = prev_eol - 1;
+       }
+       return cnt;
+ }
+ static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
+                              struct emit_callback *ecbdata)
+ {
+       int l1, l2, at;
+       unsigned ws_rule = ecbdata->ws_rule;
+       l1 = count_trailing_blank(mf1, ws_rule);
+       l2 = count_trailing_blank(mf2, ws_rule);
+       if (l2 <= l1) {
+               ecbdata->blank_at_eof_in_preimage = 0;
+               ecbdata->blank_at_eof_in_postimage = 0;
+               return;
+       }
+       at = count_lines(mf1->ptr, mf1->size);
+       ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
+       at = count_lines(mf2->ptr, mf2->size);
+       ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
+ }
+ static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
+                       int first, const char *line, int len)
+ {
+       int has_trailing_newline, has_trailing_carriage_return;
+       int nofirst;
+       FILE *file = o->file;
+       if (o->output_prefix) {
+               struct strbuf *msg = NULL;
+               msg = o->output_prefix(o, o->output_prefix_data);
+               assert(msg);
+               fwrite(msg->buf, msg->len, 1, file);
+       }
+       if (len == 0) {
+               has_trailing_newline = (first == '\n');
+               has_trailing_carriage_return = (!has_trailing_newline &&
+                                               (first == '\r'));
+               nofirst = has_trailing_newline || has_trailing_carriage_return;
+       } else {
+               has_trailing_newline = (len > 0 && line[len-1] == '\n');
+               if (has_trailing_newline)
+                       len--;
+               has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
+               if (has_trailing_carriage_return)
+                       len--;
+               nofirst = 0;
+       }
+       if (len || !nofirst) {
+               fputs(set, file);
+               if (!nofirst)
+                       fputc(first, file);
+               fwrite(line, len, 1, file);
+               fputs(reset, file);
+       }
+       if (has_trailing_carriage_return)
+               fputc('\r', file);
+       if (has_trailing_newline)
+               fputc('\n', file);
+ }
+ static void emit_line(struct diff_options *o, const char *set, const char *reset,
+                     const char *line, int len)
+ {
+       emit_line_0(o, set, reset, line[0], line+1, len-1);
+ }
+ static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
+ {
+       if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
+             ecbdata->blank_at_eof_in_preimage &&
+             ecbdata->blank_at_eof_in_postimage &&
+             ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
+             ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
+               return 0;
+       return ws_blank_line(line, len, ecbdata->ws_rule);
+ }
+ static void emit_add_line(const char *reset,
+                         struct emit_callback *ecbdata,
+                         const char *line, int len)
+ {
+       const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
+       const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
+       if (!*ws)
+               emit_line_0(ecbdata->opt, set, reset, '+', line, len);
+       else if (new_blank_line_at_eof(ecbdata, line, len))
+               /* Blank line at EOF - paint '+' as well */
+               emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
+       else {
+               /* Emit just the prefix, then the rest. */
+               emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
+               ws_check_emit(line, len, ecbdata->ws_rule,
+                             ecbdata->opt->file, set, reset, ws);
+       }
+ }
+ static void emit_hunk_header(struct emit_callback *ecbdata,
+                            const char *line, int len)
+ {
+       const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
+       const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
+       const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
+       const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
+       static const char atat[2] = { '@', '@' };
+       const char *cp, *ep;
+       struct strbuf msgbuf = STRBUF_INIT;
+       int org_len = len;
+       int i = 1;
+       /*
+        * As a hunk header must begin with "@@ -<old>, +<new> @@",
+        * it always is at least 10 bytes long.
+        */
+       if (len < 10 ||
+           memcmp(line, atat, 2) ||
+           !(ep = memmem(line + 2, len - 2, atat, 2))) {
+               emit_line(ecbdata->opt, plain, reset, line, len);
+               return;
+       }
+       ep += 2; /* skip over @@ */
+       /* The hunk header in fraginfo color */
+       strbuf_add(&msgbuf, frag, strlen(frag));
+       strbuf_add(&msgbuf, line, ep - line);
+       strbuf_add(&msgbuf, reset, strlen(reset));
+       /*
+        * trailing "\r\n"
+        */
+       for ( ; i < 3; i++)
+               if (line[len - i] == '\r' || line[len - i] == '\n')
+                       len--;
+       /* blank before the func header */
+       for (cp = ep; ep - line < len; ep++)
+               if (*ep != ' ' && *ep != '\t')
+                       break;
+       if (ep != cp) {
+               strbuf_add(&msgbuf, plain, strlen(plain));
+               strbuf_add(&msgbuf, cp, ep - cp);
+               strbuf_add(&msgbuf, reset, strlen(reset));
+       }
+       if (ep < line + len) {
+               strbuf_add(&msgbuf, func, strlen(func));
+               strbuf_add(&msgbuf, ep, line + len - ep);
+               strbuf_add(&msgbuf, reset, strlen(reset));
+       }
+       strbuf_add(&msgbuf, line + len, org_len - len);
+       emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
+       strbuf_release(&msgbuf);
+ }
  static struct diff_tempfile *claim_diff_tempfile(void) {
        int i;
        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
@@@ -201,29 -463,6 +463,6 @@@ static void remove_tempfile_on_signal(i
        raise(signo);
  }
  
- static int count_lines(const char *data, int size)
- {
-       int count, ch, completely_empty = 1, nl_just_seen = 0;
-       count = 0;
-       while (0 < size--) {
-               ch = *data++;
-               if (ch == '\n') {
-                       count++;
-                       nl_just_seen = 1;
-                       completely_empty = 0;
-               }
-               else {
-                       nl_just_seen = 0;
-                       completely_empty = 0;
-               }
-       }
-       if (completely_empty)
-               return 0;
-       if (!nl_just_seen)
-               count++; /* no trailing newline */
-       return count;
- }
  static void print_line_count(FILE *file, int count)
  {
        switch (count) {
        }
  }
  
- static void copy_file_with_prefix(FILE *file,
-                                 int prefix, const char *data, int size,
-                                 const char *set, const char *reset)
+ static void emit_rewrite_lines(struct emit_callback *ecb,
+                              int prefix, const char *data, int size)
  {
-       int ch, nl_just_seen = 1;
-       while (0 < size--) {
-               ch = *data++;
-               if (nl_just_seen) {
-                       fputs(set, file);
-                       putc(prefix, file);
+       const char *endp = NULL;
+       static const char *nneof = " No newline at end of file\n";
+       const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
+       const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
+       while (0 < size) {
+               int len;
+               endp = memchr(data, '\n', size);
+               len = endp ? (endp - data + 1) : size;
+               if (prefix != '+') {
+                       ecb->lno_in_preimage++;
+                       emit_line_0(ecb->opt, old, reset, '-',
+                                   data, len);
+               } else {
+                       ecb->lno_in_postimage++;
+                       emit_add_line(reset, ecb, data, len);
                }
-               if (ch == '\n') {
-                       nl_just_seen = 1;
-                       fputs(reset, file);
-               } else
-                       nl_just_seen = 0;
-               putc(ch, file);
+               size -= len;
+               data += len;
+       }
+       if (!endp) {
+               const char *plain = diff_get_color(ecb->color_diff,
+                                                  DIFF_PLAIN);
+               emit_line_0(ecb->opt, plain, reset, '\\',
+                           nneof, strlen(nneof));
        }
-       if (!nl_just_seen)
-               fprintf(file, "%s\n\\ No newline at end of file\n", reset);
  }
  
  static void emit_rewrite_diff(const char *name_a,
                              const char *name_b,
                              struct diff_filespec *one,
                              struct diff_filespec *two,
-                             const char *textconv_one,
-                             const char *textconv_two,
+                             struct userdiff_driver *textconv_one,
+                             struct userdiff_driver *textconv_two,
                              struct diff_options *o)
  {
        int lc_a, lc_b;
        const char *name_a_tab, *name_b_tab;
        const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
        const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
-       const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
-       const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
        const char *reset = diff_get_color(color_diff, DIFF_RESET);
        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
        const char *a_prefix, *b_prefix;
-       const char *data_one, *data_two;
+       char *data_one, *data_two;
        size_t size_one, size_two;
+       struct emit_callback ecbdata;
+       char *line_prefix = "";
+       struct strbuf *msgbuf;
+       if (o && o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
                a_prefix = o->b_prefix;
        quote_two_c_style(&a_name, a_prefix, name_a, 0);
        quote_two_c_style(&b_name, b_prefix, name_b, 0);
  
-       diff_populate_filespec(one, 0);
-       diff_populate_filespec(two, 0);
-       if (textconv_one) {
-               data_one = run_textconv(textconv_one, one, &size_one);
-               if (!data_one)
-                       die("unable to read files to diff");
-       }
-       else {
-               data_one = one->data;
-               size_one = one->size;
-       }
-       if (textconv_two) {
-               data_two = run_textconv(textconv_two, two, &size_two);
-               if (!data_two)
-                       die("unable to read files to diff");
-       }
-       else {
-               data_two = two->data;
-               size_two = two->size;
+       size_one = fill_textconv(textconv_one, one, &data_one);
+       size_two = fill_textconv(textconv_two, two, &data_two);
+       memset(&ecbdata, 0, sizeof(ecbdata));
+       ecbdata.color_diff = color_diff;
+       ecbdata.found_changesp = &o->found_changes;
+       ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
+       ecbdata.opt = o;
+       if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
+               mmfile_t mf1, mf2;
+               mf1.ptr = (char *)data_one;
+               mf2.ptr = (char *)data_two;
+               mf1.size = size_one;
+               mf2.size = size_two;
+               check_blank_at_eof(&mf1, &mf2, &ecbdata);
        }
+       ecbdata.lno_in_preimage = 1;
+       ecbdata.lno_in_postimage = 1;
  
        lc_a = count_lines(data_one, size_one);
        lc_b = count_lines(data_two, size_two);
        fprintf(o->file,
-               "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
-               metainfo, a_name.buf, name_a_tab, reset,
-               metainfo, b_name.buf, name_b_tab, reset, fraginfo);
+               "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
+               line_prefix, metainfo, a_name.buf, name_a_tab, reset,
+               line_prefix, metainfo, b_name.buf, name_b_tab, reset,
+               line_prefix, fraginfo);
        print_line_count(o->file, lc_a);
        fprintf(o->file, " +");
        print_line_count(o->file, lc_b);
        fprintf(o->file, " @@%s\n", reset);
        if (lc_a)
-               copy_file_with_prefix(o->file, '-', data_one, size_one, old, reset);
+               emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
        if (lc_b)
-               copy_file_with_prefix(o->file, '+', data_two, size_two, new, reset);
- }
- static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
- {
-       if (!DIFF_FILE_VALID(one)) {
-               mf->ptr = (char *)""; /* does not matter */
-               mf->size = 0;
-               return 0;
-       }
-       else if (diff_populate_filespec(one, 0))
-               return -1;
-       mf->ptr = one->data;
-       mf->size = one->size;
-       return 0;
+               emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
+       if (textconv_one)
+               free((char *)data_one);
+       if (textconv_two)
+               free((char *)data_two);
  }
  
  struct diff_words_buffer {
@@@ -372,23 -615,132 +615,132 @@@ static void diff_words_append(char *lin
        buffer->text.ptr[buffer->text.size] = '\0';
  }
  
+ struct diff_words_style_elem {
+       const char *prefix;
+       const char *suffix;
+       const char *color; /* NULL; filled in by the setup code if
+                           * color is enabled */
+ };
+ struct diff_words_style {
+       enum diff_words_type type;
+       struct diff_words_style_elem new, old, ctx;
+       const char *newline;
+ };
+ static struct diff_words_style diff_words_styles[] = {
+       { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
+       { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
+       { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
+ };
  struct diff_words_data {
        struct diff_words_buffer minus, plus;
        const char *current_plus;
-       FILE *file;
+       int last_minus;
+       struct diff_options *opt;
        regex_t *word_regex;
+       enum diff_words_type type;
+       struct diff_words_style *style;
  };
  
+ static int fn_out_diff_words_write_helper(FILE *fp,
+                                         struct diff_words_style_elem *st_el,
+                                         const char *newline,
+                                         size_t count, const char *buf,
+                                         const char *line_prefix)
+ {
+       int print = 0;
+       while (count) {
+               char *p = memchr(buf, '\n', count);
+               if (print)
+                       fputs(line_prefix, fp);
+               if (p != buf) {
+                       if (st_el->color && fputs(st_el->color, fp) < 0)
+                               return -1;
+                       if (fputs(st_el->prefix, fp) < 0 ||
+                           fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
+                           fputs(st_el->suffix, fp) < 0)
+                               return -1;
+                       if (st_el->color && *st_el->color
+                           && fputs(GIT_COLOR_RESET, fp) < 0)
+                               return -1;
+               }
+               if (!p)
+                       return 0;
+               if (fputs(newline, fp) < 0)
+                       return -1;
+               count -= p + 1 - buf;
+               buf = p + 1;
+               print = 1;
+       }
+       return 0;
+ }
+ /*
+  * '--color-words' algorithm can be described as:
+  *
+  *   1. collect a the minus/plus lines of a diff hunk, divided into
+  *      minus-lines and plus-lines;
+  *
+  *   2. break both minus-lines and plus-lines into words and
+  *      place them into two mmfile_t with one word for each line;
+  *
+  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
+  *
+  * And for the common parts of the both file, we output the plus side text.
+  * diff_words->current_plus is used to trace the current position of the plus file
+  * which printed. diff_words->last_minus is used to trace the last minus word
+  * printed.
+  *
+  * For '--graph' to work with '--color-words', we need to output the graph prefix
+  * on each line of color words output. Generally, there are two conditions on
+  * which we should output the prefix.
+  *
+  *   1. diff_words->last_minus == 0 &&
+  *      diff_words->current_plus == diff_words->plus.text.ptr
+  *
+  *      that is: the plus text must start as a new line, and if there is no minus
+  *      word printed, a graph prefix must be printed.
+  *
+  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
+  *      *(diff_words->current_plus - 1) == '\n'
+  *
+  *      that is: a graph prefix must be printed following a '\n'
+  */
+ static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
+ {
+       if ((diff_words->last_minus == 0 &&
+               diff_words->current_plus == diff_words->plus.text.ptr) ||
+               (diff_words->current_plus > diff_words->plus.text.ptr &&
+               *(diff_words->current_plus - 1) == '\n')) {
+               return 1;
+       } else {
+               return 0;
+       }
+ }
  static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
  {
        struct diff_words_data *diff_words = priv;
+       struct diff_words_style *style = diff_words->style;
        int minus_first, minus_len, plus_first, plus_len;
        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
+       struct diff_options *opt = diff_words->opt;
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
  
        if (line[0] != '@' || parse_hunk_header(line, len,
                        &minus_first, &minus_len, &plus_first, &plus_len))
                return;
  
+       assert(opt);
+       if (opt->output_prefix) {
+               msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
        /* POSIX requires that first be decremented by one if len == 0... */
        if (minus_len) {
                minus_begin = diff_words->minus.orig[minus_first].begin;
        } else
                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
  
-       if (diff_words->current_plus != plus_begin)
-               fwrite(diff_words->current_plus,
-                               plus_begin - diff_words->current_plus, 1,
-                               diff_words->file);
-       if (minus_begin != minus_end)
-               color_fwrite_lines(diff_words->file,
-                               diff_get_color(1, DIFF_FILE_OLD),
-                               minus_end - minus_begin, minus_begin);
-       if (plus_begin != plus_end)
-               color_fwrite_lines(diff_words->file,
-                               diff_get_color(1, DIFF_FILE_NEW),
-                               plus_end - plus_begin, plus_begin);
+       if (color_words_output_graph_prefix(diff_words)) {
+               fputs(line_prefix, diff_words->opt->file);
+       }
+       if (diff_words->current_plus != plus_begin) {
+               fn_out_diff_words_write_helper(diff_words->opt->file,
+                               &style->ctx, style->newline,
+                               plus_begin - diff_words->current_plus,
+                               diff_words->current_plus, line_prefix);
+               if (*(plus_begin - 1) == '\n')
+                       fputs(line_prefix, diff_words->opt->file);
+       }
+       if (minus_begin != minus_end) {
+               fn_out_diff_words_write_helper(diff_words->opt->file,
+                               &style->old, style->newline,
+                               minus_end - minus_begin, minus_begin,
+                               line_prefix);
+       }
+       if (plus_begin != plus_end) {
+               fn_out_diff_words_write_helper(diff_words->opt->file,
+                               &style->new, style->newline,
+                               plus_end - plus_begin, plus_begin,
+                               line_prefix);
+       }
  
        diff_words->current_plus = plus_end;
+       diff_words->last_minus = minus_first;
  }
  
  /* This function starts looking at *begin, and returns 0 iff a word was found. */
@@@ -495,65 -859,77 +859,77 @@@ static void diff_words_show(struct diff
  {
        xpparam_t xpp;
        xdemitconf_t xecfg;
-       xdemitcb_t ecb;
        mmfile_t minus, plus;
+       struct diff_words_style *style = diff_words->style;
+       struct diff_options *opt = diff_words->opt;
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
+       assert(opt);
+       if (opt->output_prefix) {
+               msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        /* special case: only removal */
        if (!diff_words->plus.text.size) {
-               color_fwrite_lines(diff_words->file,
-                       diff_get_color(1, DIFF_FILE_OLD),
-                       diff_words->minus.text.size, diff_words->minus.text.ptr);
+               fputs(line_prefix, diff_words->opt->file);
+               fn_out_diff_words_write_helper(diff_words->opt->file,
+                       &style->old, style->newline,
+                       diff_words->minus.text.size,
+                       diff_words->minus.text.ptr, line_prefix);
                diff_words->minus.text.size = 0;
                return;
        }
  
        diff_words->current_plus = diff_words->plus.text.ptr;
+       diff_words->last_minus = 0;
  
        memset(&xpp, 0, sizeof(xpp));
        memset(&xecfg, 0, sizeof(xecfg));
        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
-       xpp.flags = XDF_NEED_MINIMAL;
+       xpp.flags = 0;
        /* as only the hunk header will be parsed, we need a 0-context */
        xecfg.ctxlen = 0;
        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
-                     &xpp, &xecfg, &ecb);
+                     &xpp, &xecfg);
        free(minus.ptr);
        free(plus.ptr);
        if (diff_words->current_plus != diff_words->plus.text.ptr +
-                       diff_words->plus.text.size)
-               fwrite(diff_words->current_plus,
+                       diff_words->plus.text.size) {
+               if (color_words_output_graph_prefix(diff_words))
+                       fputs(line_prefix, diff_words->opt->file);
+               fn_out_diff_words_write_helper(diff_words->opt->file,
+                       &style->ctx, style->newline,
                        diff_words->plus.text.ptr + diff_words->plus.text.size
-                       - diff_words->current_plus, 1,
-                       diff_words->file);
+                       - diff_words->current_plus, diff_words->current_plus,
+                       line_prefix);
+       }
        diff_words->minus.text.size = diff_words->plus.text.size = 0;
  }
  
- typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
- struct emit_callback {
-       int nparents, color_diff;
-       unsigned ws_rule;
-       sane_truncate_fn truncate;
-       const char **label_path;
-       struct diff_words_data *diff_words;
-       int *found_changesp;
-       FILE *file;
- };
+ /* In "color-words" mode, show word-diff of words accumulated in the buffer */
+ static void diff_words_flush(struct emit_callback *ecbdata)
+ {
+       if (ecbdata->diff_words->minus.text.size ||
+           ecbdata->diff_words->plus.text.size)
+               diff_words_show(ecbdata->diff_words);
+ }
  
  static void free_diff_words_data(struct emit_callback *ecbdata)
  {
        if (ecbdata->diff_words) {
-               /* flush buffers */
-               if (ecbdata->diff_words->minus.text.size ||
-                               ecbdata->diff_words->plus.text.size)
-                       diff_words_show(ecbdata->diff_words);
+               diff_words_flush(ecbdata);
                free (ecbdata->diff_words->minus.text.ptr);
                free (ecbdata->diff_words->minus.orig);
                free (ecbdata->diff_words->plus.text.ptr);
                free (ecbdata->diff_words->plus.orig);
-               free(ecbdata->diff_words->word_regex);
+               if (ecbdata->diff_words->word_regex) {
+                       regfree(ecbdata->diff_words->word_regex);
+                       free(ecbdata->diff_words->word_regex);
+               }
                free(ecbdata->diff_words);
                ecbdata->diff_words = NULL;
        }
@@@ -566,42 -942,6 +942,6 @@@ const char *diff_get_color(int diff_use
        return "";
  }
  
- static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
- {
-       int has_trailing_newline, has_trailing_carriage_return;
-       has_trailing_newline = (len > 0 && line[len-1] == '\n');
-       if (has_trailing_newline)
-               len--;
-       has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
-       if (has_trailing_carriage_return)
-               len--;
-       fputs(set, file);
-       fwrite(line, len, 1, file);
-       fputs(reset, file);
-       if (has_trailing_carriage_return)
-               fputc('\r', file);
-       if (has_trailing_newline)
-               fputc('\n', file);
- }
- static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
- {
-       const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
-       const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
-       if (!*ws)
-               emit_line(ecbdata->file, set, reset, line, len);
-       else {
-               /* Emit just the prefix, then the rest. */
-               emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
-               ws_check_emit(line + ecbdata->nparents,
-                             len - ecbdata->nparents, ecbdata->ws_rule,
-                             ecbdata->file, set, reset, ws);
-       }
- }
  static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
  {
        const char *cp;
        return allot - l;
  }
  
+ static void find_lno(const char *line, struct emit_callback *ecbdata)
+ {
+       const char *p;
+       ecbdata->lno_in_preimage = 0;
+       ecbdata->lno_in_postimage = 0;
+       p = strchr(line, '-');
+       if (!p)
+               return; /* cannot happen */
+       ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
+       p = strchr(p, '+');
+       if (!p)
+               return; /* cannot happen */
+       ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
+ }
  static void fn_out_consume(void *priv, char *line, unsigned long len)
  {
-       int i;
-       int color;
        struct emit_callback *ecbdata = priv;
        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
+       struct diff_options *o = ecbdata->opt;
+       char *line_prefix = "";
+       struct strbuf *msgbuf;
+       if (o && o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
+       if (ecbdata->header) {
+               fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
+               strbuf_reset(ecbdata->header);
+               ecbdata->header = NULL;
+       }
        *(ecbdata->found_changesp) = 1;
  
        if (ecbdata->label_path[0]) {
                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
  
-               fprintf(ecbdata->file, "%s--- %s%s%s\n",
-                       meta, ecbdata->label_path[0], reset, name_a_tab);
-               fprintf(ecbdata->file, "%s+++ %s%s%s\n",
-                       meta, ecbdata->label_path[1], reset, name_b_tab);
+               fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
+                       line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
+               fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
+                       line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
        }
  
                len = 1;
        }
  
-       /* This is not really necessary for now because
-        * this codepath only deals with two-way diffs.
-        */
-       for (i = 0; i < len && line[i] == '@'; i++)
-               ;
-       if (2 <= i && i < len && line[i] == ' ') {
-               ecbdata->nparents = i - 1;
+       if (line[0] == '@') {
+               if (ecbdata->diff_words)
+                       diff_words_flush(ecbdata);
                len = sane_truncate_line(ecbdata, line, len);
-               emit_line(ecbdata->file,
-                         diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
-                         reset, line, len);
+               find_lno(line, ecbdata);
+               emit_hunk_header(ecbdata, line, len);
                if (line[len-1] != '\n')
-                       putc('\n', ecbdata->file);
+                       putc('\n', ecbdata->opt->file);
                return;
        }
  
-       if (len < ecbdata->nparents) {
-               emit_line(ecbdata->file, reset, reset, line, len);
+       if (len < 1) {
+               emit_line(ecbdata->opt, reset, reset, line, len);
+               if (ecbdata->diff_words
+                   && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
+                       fputs("~\n", ecbdata->opt->file);
                return;
        }
  
-       color = DIFF_PLAIN;
-       if (ecbdata->diff_words && ecbdata->nparents != 1)
-               /* fall back to normal diff */
-               free_diff_words_data(ecbdata);
        if (ecbdata->diff_words) {
                if (line[0] == '-') {
                        diff_words_append(line, len,
                                          &ecbdata->diff_words->plus);
                        return;
                }
-               if (ecbdata->diff_words->minus.text.size ||
-                   ecbdata->diff_words->plus.text.size)
-                       diff_words_show(ecbdata->diff_words);
-               line++;
-               len--;
-               emit_line(ecbdata->file, plain, reset, line, len);
+               diff_words_flush(ecbdata);
+               if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
+                       emit_line(ecbdata->opt, plain, reset, line, len);
+                       fputs("~\n", ecbdata->opt->file);
+               } else {
+                       /*
+                        * Skip the prefix character, if any.  With
+                        * diff_suppress_blank_empty, there may be
+                        * none.
+                        */
+                       if (line[0] != '\n') {
+                             line++;
+                             len--;
+                       }
+                       emit_line(ecbdata->opt, plain, reset, line, len);
+               }
                return;
        }
-       for (i = 0; i < ecbdata->nparents && len; i++) {
-               if (line[i] == '-')
-                       color = DIFF_FILE_OLD;
-               else if (line[i] == '+')
-                       color = DIFF_FILE_NEW;
-       }
  
-       if (color != DIFF_FILE_NEW) {
-               emit_line(ecbdata->file,
-                         diff_get_color(ecbdata->color_diff, color),
-                         reset, line, len);
-               return;
+       if (line[0] != '+') {
+               const char *color =
+                       diff_get_color(ecbdata->color_diff,
+                                      line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
+               ecbdata->lno_in_preimage++;
+               if (line[0] == ' ')
+                       ecbdata->lno_in_postimage++;
+               emit_line(ecbdata->opt, color, reset, line, len);
+       } else {
+               ecbdata->lno_in_postimage++;
+               emit_add_line(reset, ecbdata, line + 1, len - 1);
        }
-       emit_add_line(reset, ecbdata, line, len);
  }
  
  static char *pprint_rename(const char *a, const char *b)
@@@ -786,7 -1155,7 +1155,7 @@@ struct diffstat_t 
                unsigned is_unmerged:1;
                unsigned is_binary:1;
                unsigned is_renamed:1;
-               unsigned int added, deleted;
+               uintmax_t added, deleted;
        } **files;
  };
  
@@@ -878,14 -1247,21 +1247,21 @@@ static void fill_print_name(struct diff
  static void show_stats(struct diffstat_t *data, struct diff_options *options)
  {
        int i, len, add, del, adds = 0, dels = 0;
-       int max_change = 0, max_len = 0;
+       uintmax_t max_change = 0, max_len = 0;
        int total_files = data->nr;
        int width, name_width;
-       const char *reset, *set, *add_c, *del_c;
+       const char *reset, *add_c, *del_c;
+       const char *line_prefix = "";
+       struct strbuf *msg = NULL;
  
        if (data->nr == 0)
                return;
  
+       if (options->output_prefix) {
+               msg = options->output_prefix(options, options->output_prefix_data);
+               line_prefix = msg->buf;
+       }
        width = options->stat_width ? options->stat_width : 80;
        name_width = options->stat_name_width ? options->stat_name_width : 50;
  
  
        /* Find the longest filename and max number of changes */
        reset = diff_get_color_opt(options, DIFF_RESET);
-       set   = diff_get_color_opt(options, DIFF_PLAIN);
        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
  
        for (i = 0; i < data->nr; i++) {
                struct diffstat_file *file = data->files[i];
-               int change = file->added + file->deleted;
+               uintmax_t change = file->added + file->deleted;
                fill_print_name(file);
                len = strlen(file->print_name);
                if (max_len < len)
        for (i = 0; i < data->nr; i++) {
                const char *prefix = "";
                char *name = data->files[i]->print_name;
-               int added = data->files[i]->added;
-               int deleted = data->files[i]->deleted;
+               uintmax_t added = data->files[i]->added;
+               uintmax_t deleted = data->files[i]->deleted;
                int name_len;
  
                /*
                }
  
                if (data->files[i]->is_binary) {
+                       fprintf(options->file, "%s", line_prefix);
                        show_name(options->file, prefix, name, len);
                        fprintf(options->file, "  Bin ");
-                       fprintf(options->file, "%s%d%s", del_c, deleted, reset);
+                       fprintf(options->file, "%s%"PRIuMAX"%s",
+                               del_c, deleted, reset);
                        fprintf(options->file, " -> ");
-                       fprintf(options->file, "%s%d%s", add_c, added, reset);
+                       fprintf(options->file, "%s%"PRIuMAX"%s",
+                               add_c, added, reset);
                        fprintf(options->file, " bytes");
                        fprintf(options->file, "\n");
                        continue;
                }
                else if (data->files[i]->is_unmerged) {
+                       fprintf(options->file, "%s", line_prefix);
                        show_name(options->file, prefix, name, len);
                        fprintf(options->file, "  Unmerged\n");
                        continue;
                        add = scale_linear(add, width, max_change);
                        del = scale_linear(del, width, max_change);
                }
+               fprintf(options->file, "%s", line_prefix);
                show_name(options->file, prefix, name, len);
-               fprintf(options->file, "%5d%s", added + deleted,
+               fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
                                added + deleted ? " " : "");
                show_graph(options->file, '+', add, add_c, reset);
                show_graph(options->file, '-', del, del_c, reset);
                fprintf(options->file, "\n");
        }
+       fprintf(options->file, "%s", line_prefix);
        fprintf(options->file,
               " %d files changed, %d insertions(+), %d deletions(-)\n",
               total_files, adds, dels);
  }
  
- static void show_shortstats(struct diffstat_tdata, struct diff_options *options)
+ static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
  {
        int i, adds = 0, dels = 0, total_files = data->nr;
  
                        }
                }
        }
+       if (options->output_prefix) {
+               struct strbuf *msg = NULL;
+               msg = options->output_prefix(options,
+                               options->output_prefix_data);
+               fprintf(options->file, "%s", msg->buf);
+       }
        fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
               total_files, adds, dels);
  }
@@@ -1034,11 -1421,19 +1421,19 @@@ static void show_numstat(struct diffsta
        for (i = 0; i < data->nr; i++) {
                struct diffstat_file *file = data->files[i];
  
+               if (options->output_prefix) {
+                       struct strbuf *msg = NULL;
+                       msg = options->output_prefix(options,
+                                       options->output_prefix_data);
+                       fprintf(options->file, "%s", msg->buf);
+               }
                if (file->is_binary)
                        fprintf(options->file, "-\t-\t");
                else
                        fprintf(options->file,
-                               "%d\t%d\t", file->added, file->deleted);
+                               "%"PRIuMAX"\t%"PRIuMAX"\t",
+                               file->added, file->deleted);
                if (options->line_termination) {
                        fill_print_name(file);
                        if (!file->is_renamed)
@@@ -1068,10 -1463,18 +1463,18 @@@ struct dirstat_dir 
        int alloc, nr, percent, cumulative;
  };
  
- static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
+ static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
+               unsigned long changed, const char *base, int baselen)
  {
        unsigned long this_dir = 0;
        unsigned int sources = 0;
+       const char *line_prefix = "";
+       struct strbuf *msg = NULL;
+       if (opt->output_prefix) {
+               msg = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = msg->buf;
+       }
  
        while (dir->nr) {
                struct dirstat_file *f = dir->files;
                slash = strchr(f->name + baselen, '/');
                if (slash) {
                        int newbaselen = slash + 1 - f->name;
-                       this = gather_dirstat(file, dir, changed, f->name, newbaselen);
+                       this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
                        sources++;
                } else {
                        this = f->changed;
                if (permille) {
                        int percent = permille / 10;
                        if (percent >= dir->percent) {
-                               fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
+                               fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
+                                       percent, permille % 10, baselen, base);
                                if (!dir->cumulative)
                                        return 0;
                        }
@@@ -1142,8 -1546,36 +1546,36 @@@ static void show_dirstat(struct diff_op
                struct diff_filepair *p = q->queue[i];
                const char *name;
                unsigned long copied, added, damage;
+               int content_changed;
+               name = p->two->path ? p->two->path : p->one->path;
  
-               name = p->one->path ? p->one->path : p->two->path;
+               if (p->one->sha1_valid && p->two->sha1_valid)
+                       content_changed = hashcmp(p->one->sha1, p->two->sha1);
+               else
+                       content_changed = 1;
+               if (!content_changed) {
+                       /*
+                        * The SHA1 has not changed, so pre-/post-content is
+                        * identical. We can therefore skip looking at the
+                        * file contents altogether.
+                        */
+                       damage = 0;
+                       goto found_damage;
+               }
+               if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
+                       /*
+                        * In --dirstat-by-file mode, we don't really need to
+                        * look at the actual file contents at all.
+                        * The fact that the SHA1 changed is enough for us to
+                        * add this file to the list of results
+                        * (with each file contributing equal damage).
+                        */
+                       damage = 1;
+                       goto found_damage;
+               }
  
                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
                        diff_populate_filespec(p->one, 0);
                /*
                 * Original minus copied is the removed material,
                 * added is the new material.  They are both damages
-                * made to the preimage. In --dirstat-by-file mode, count
-                * damaged files, not damaged lines. This is done by
-                * counting only a single damaged line per file.
+                * made to the preimage.
+                * If the resulting damage is zero, we know that
+                * diffcore_count_changes() considers the two entries to
+                * be identical, but since content_changed is true, we
+                * know that there must have been _some_ kind of change,
+                * so we force all entries to have damage > 0.
                 */
                damage = (p->one->size - copied) + added;
-               if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE) && damage > 0)
+               if (!damage)
                        damage = 1;
  
+ found_damage:
                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
                dir.files[dir.nr].name = name;
                dir.files[dir.nr].changed = damage;
  
        /* Show all directories with more than x% of the changes */
        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
-       gather_dirstat(options->file, &dir, changed, "", 0);
+       gather_dirstat(options, &dir, changed, "", 0);
  }
  
  static void free_diffstat_info(struct diffstat_t *diffstat)
  struct checkdiff_t {
        const char *filename;
        int lineno;
+       int conflict_marker_size;
        struct diff_options *o;
        unsigned ws_rule;
        unsigned status;
-       int trailing_blanks_start;
  };
  
- static int is_conflict_marker(const char *line, unsigned long len)
+ static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
  {
        char firstchar;
        int cnt;
  
-       if (len < 8)
+       if (len < marker_size + 1)
                return 0;
        firstchar = line[0];
        switch (firstchar) {
-       case '=': case '>': case '<':
+       case '=': case '>': case '<': case '|':
                break;
        default:
                return 0;
        }
-       for (cnt = 1; cnt < 7; cnt++)
+       for (cnt = 1; cnt < marker_size; cnt++)
                if (line[cnt] != firstchar)
                        return 0;
-       /* line[0] thru line[6] are same as firstchar */
-       if (firstchar == '=') {
-               /* divider between ours and theirs? */
-               if (len != 8 || line[7] != '\n')
-                       return 0;
-       } else if (len < 8 || !isspace(line[7])) {
-               /* not divider before ours nor after theirs */
+       /* line[1] thru line[marker_size-1] are same as firstchar */
+       if (len < marker_size + 1 || !isspace(line[marker_size]))
                return 0;
-       }
        return 1;
  }
  
@@@ -1247,45 -1677,49 +1677,49 @@@ static void checkdiff_consume(void *pri
  {
        struct checkdiff_t *data = priv;
        int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
+       int marker_size = data->conflict_marker_size;
        const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
        const char *reset = diff_get_color(color_diff, DIFF_RESET);
        const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
        char *err;
+       char *line_prefix = "";
+       struct strbuf *msgbuf;
+       assert(data->o);
+       if (data->o->output_prefix) {
+               msgbuf = data->o->output_prefix(data->o,
+                       data->o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
  
        if (line[0] == '+') {
                unsigned bad;
                data->lineno++;
-               if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
-                       data->trailing_blanks_start = 0;
-               else if (!data->trailing_blanks_start)
-                       data->trailing_blanks_start = data->lineno;
-               if (is_conflict_marker(line + 1, len - 1)) {
+               if (is_conflict_marker(line + 1, marker_size, len - 1)) {
                        data->status |= 1;
                        fprintf(data->o->file,
-                               "%s:%d: leftover conflict marker\n",
-                               data->filename, data->lineno);
+                               "%s%s:%d: leftover conflict marker\n",
+                               line_prefix, data->filename, data->lineno);
                }
                bad = ws_check(line + 1, len - 1, data->ws_rule);
                if (!bad)
                        return;
                data->status |= bad;
                err = whitespace_error_string(bad);
-               fprintf(data->o->file, "%s:%d: %s.\n",
-                       data->filename, data->lineno, err);
+               fprintf(data->o->file, "%s%s:%d: %s.\n",
+                       line_prefix, data->filename, data->lineno, err);
                free(err);
-               emit_line(data->o->file, set, reset, line, 1);
+               emit_line(data->o, set, reset, line, 1);
                ws_check_emit(line + 1, len - 1, data->ws_rule,
                              data->o->file, set, reset, ws);
        } else if (line[0] == ' ') {
                data->lineno++;
-               data->trailing_blanks_start = 0;
        } else if (line[0] == '@') {
                char *plus = strchr(line, '+');
                if (plus)
                        data->lineno = strtol(plus, NULL, 10) - 1;
                else
                        die("invalid diff");
-               data->trailing_blanks_start = 0;
        }
  }
  
@@@ -1313,7 -1747,7 +1747,7 @@@ static unsigned char *deflate_it(char *
        return deflated;
  }
  
- static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
+ static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
  {
        void *cp;
        void *delta;
        }
  
        if (delta && delta_size < deflate_size) {
-               fprintf(file, "delta %lu\n", orig_size);
+               fprintf(file, "%sdelta %lu\n", prefix, orig_size);
                free(deflated);
                data = delta;
                data_size = delta_size;
        }
        else {
-               fprintf(file, "literal %lu\n", two->size);
+               fprintf(file, "%sliteral %lu\n", prefix, two->size);
                free(delta);
                data = deflated;
                data_size = deflate_size;
                        line[0] = bytes - 26 + 'a' - 1;
                encode_85(line + 1, cp, bytes);
                cp = (char *) cp + bytes;
+               fprintf(file, "%s", prefix);
                fputs(line, file);
                fputc('\n', file);
        }
-       fprintf(file, "\n");
+       fprintf(file, "%s\n", prefix);
        free(data);
  }
  
- static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
+ static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
  {
-       fprintf(file, "GIT binary patch\n");
-       emit_binary_diff_body(file, one, two);
-       emit_binary_diff_body(file, two, one);
+       fprintf(file, "%sGIT binary patch\n", prefix);
+       emit_binary_diff_body(file, one, two, prefix);
+       emit_binary_diff_body(file, two, one, prefix);
  }
  
  static void diff_filespec_load_driver(struct diff_filespec *one)
  {
-       if (!one->driver)
+       /* Use already-loaded driver */
+       if (one->driver)
+               return;
+       if (S_ISREG(one->mode))
                one->driver = userdiff_find_by_path(one->path);
+       /* Fallback to default settings */
        if (!one->driver)
                one->driver = userdiff_find_by_name("default");
  }
@@@ -1427,14 -1868,25 +1868,25 @@@ void diff_set_mnemonic_prefix(struct di
                options->b_prefix = b;
  }
  
- static const char *get_textconv(struct diff_filespec *one)
+ struct userdiff_driver *get_textconv(struct diff_filespec *one)
  {
        if (!DIFF_FILE_VALID(one))
                return NULL;
-       if (!S_ISREG(one->mode))
-               return NULL;
        diff_filespec_load_driver(one);
-       return one->driver->textconv;
+       if (!one->driver->textconv)
+               return NULL;
+       if (one->driver->textconv_want_cache && !one->driver->textconv_cache) {
+               struct notes_cache *c = xmalloc(sizeof(*c));
+               struct strbuf name = STRBUF_INIT;
+               strbuf_addf(&name, "textconv/%s", one->driver->name);
+               notes_cache_init(c, name.buf, one->driver->textconv);
+               one->driver->textconv_cache = c;
+       }
+       return one->driver;
  }
  
  static void builtin_diff(const char *name_a,
                         struct diff_filespec *one,
                         struct diff_filespec *two,
                         const char *xfrm_msg,
+                        int must_show_header,
                         struct diff_options *o,
                         int complete_rewrite)
  {
        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
        const char *reset = diff_get_color_opt(o, DIFF_RESET);
        const char *a_prefix, *b_prefix;
-       const char *textconv_one = NULL, *textconv_two = NULL;
+       struct userdiff_driver *textconv_one = NULL;
+       struct userdiff_driver *textconv_two = NULL;
+       struct strbuf header = STRBUF_INIT;
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
+       if (o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
+       if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
+                       (!one->mode || S_ISGITLINK(one->mode)) &&
+                       (!two->mode || S_ISGITLINK(two->mode))) {
+               const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
+               const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
+               show_submodule_summary(o->file, one ? one->path : two->path,
+                               one->sha1, two->sha1, two->dirty_submodule,
+                               del, add, reset);
+               return;
+       }
  
        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
                textconv_one = get_textconv(one);
        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
-       fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
+       strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
        if (lbl[0][0] == '/') {
                /* /dev/null */
-               fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
-               if (xfrm_msg && xfrm_msg[0])
-                       fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
+               strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
+               if (xfrm_msg)
+                       strbuf_addstr(&header, xfrm_msg);
+               must_show_header = 1;
        }
        else if (lbl[1][0] == '/') {
-               fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
-               if (xfrm_msg && xfrm_msg[0])
-                       fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
+               strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
+               if (xfrm_msg)
+                       strbuf_addstr(&header, xfrm_msg);
+               must_show_header = 1;
        }
        else {
                if (one->mode != two->mode) {
-                       fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
-                       fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
+                       strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
+                       strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
+                       must_show_header = 1;
                }
-               if (xfrm_msg && xfrm_msg[0])
-                       fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
+               if (xfrm_msg)
+                       strbuf_addstr(&header, xfrm_msg);
                /*
                 * we do not run diff between different kind
                 * of objects.
                if (complete_rewrite &&
                    (textconv_one || !diff_filespec_is_binary(one)) &&
                    (textconv_two || !diff_filespec_is_binary(two))) {
+                       fprintf(o->file, "%s", header.buf);
+                       strbuf_reset(&header);
                        emit_rewrite_diff(name_a, name_b, one, two,
                                                textconv_one, textconv_two, o);
                        o->found_changes = 1;
                }
        }
  
-       if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
-               die("unable to read files to diff");
        if (!DIFF_OPT_TST(o, TEXT) &&
-           ( (diff_filespec_is_binary(one) && !textconv_one) ||
-             (diff_filespec_is_binary(two) && !textconv_two) )) {
+           ( (!textconv_one && diff_filespec_is_binary(one)) ||
+             (!textconv_two && diff_filespec_is_binary(two)) )) {
+               if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
+                       die("unable to read files to diff");
                /* Quite common confusing case */
                if (mf1.size == mf2.size &&
-                   !memcmp(mf1.ptr, mf2.ptr, mf1.size))
+                   !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
+                       if (must_show_header)
+                               fprintf(o->file, "%s", header.buf);
                        goto free_ab_and_return;
+               }
+               fprintf(o->file, "%s", header.buf);
+               strbuf_reset(&header);
                if (DIFF_OPT_TST(o, BINARY))
-                       emit_binary_diff(o->file, &mf1, &mf2);
+                       emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
                else
-                       fprintf(o->file, "Binary files %s and %s differ\n",
-                               lbl[0], lbl[1]);
+                       fprintf(o->file, "%sBinary files %s and %s differ\n",
+                               line_prefix, lbl[0], lbl[1]);
                o->found_changes = 1;
        }
        else {
                const char *diffopts = getenv("GIT_DIFF_OPTS");
                xpparam_t xpp;
                xdemitconf_t xecfg;
-               xdemitcb_t ecb;
                struct emit_callback ecbdata;
                const struct userdiff_funcname *pe;
  
-               if (textconv_one) {
-                       size_t size;
-                       mf1.ptr = run_textconv(textconv_one, one, &size);
-                       if (!mf1.ptr)
-                               die("unable to read files to diff");
-                       mf1.size = size;
-               }
-               if (textconv_two) {
-                       size_t size;
-                       mf2.ptr = run_textconv(textconv_two, two, &size);
-                       if (!mf2.ptr)
-                               die("unable to read files to diff");
-                       mf2.size = size;
+               if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
+                       fprintf(o->file, "%s", header.buf);
+                       strbuf_reset(&header);
                }
  
+               mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
+               mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
                pe = diff_funcname_pattern(one);
                if (!pe)
                        pe = diff_funcname_pattern(two);
                ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
                ecbdata.found_changesp = &o->found_changes;
                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
-               ecbdata.file = o->file;
-               xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
+               if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
+                       check_blank_at_eof(&mf1, &mf2, &ecbdata);
+               ecbdata.opt = o;
+               ecbdata.header = header.len ? &header : NULL;
+               xpp.flags = o->xdl_opts;
                xecfg.ctxlen = o->context;
                xecfg.interhunkctxlen = o->interhunkcontext;
                xecfg.flags = XDL_EMIT_FUNCNAMES;
                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
                else if (!prefixcmp(diffopts, "-u"))
                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
-               if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
+               if (o->word_diff) {
+                       int i;
                        ecbdata.diff_words =
                                xcalloc(1, sizeof(struct diff_words_data));
-                       ecbdata.diff_words->file = o->file;
+                       ecbdata.diff_words->type = o->word_diff;
+                       ecbdata.diff_words->opt = o;
                        if (!o->word_regex)
                                o->word_regex = userdiff_word_regex(one);
                        if (!o->word_regex)
                                        die ("Invalid regular expression: %s",
                                                        o->word_regex);
                        }
+                       for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
+                               if (o->word_diff == diff_words_styles[i].type) {
+                                       ecbdata.diff_words->style =
+                                               &diff_words_styles[i];
+                                       break;
+                               }
+                       }
+                       if (DIFF_OPT_TST(o, COLOR_DIFF)) {
+                               struct diff_words_style *st = ecbdata.diff_words->style;
+                               st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
+                               st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
+                               st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
+                       }
                }
                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
-                             &xpp, &xecfg, &ecb);
-               if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
+                             &xpp, &xecfg);
+               if (o->word_diff)
                        free_diff_words_data(&ecbdata);
                if (textconv_one)
                        free(mf1.ptr);
        }
  
   free_ab_and_return:
+       strbuf_release(&header);
        diff_free_filespec_data(one);
        diff_free_filespec_data(two);
        free(a_one);
@@@ -1630,34 -2125,35 +2125,35 @@@ static void builtin_diffstat(const cha
                data->is_unmerged = 1;
                return;
        }
-       if (complete_rewrite) {
+       if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
+               data->is_binary = 1;
+               data->added = diff_filespec_size(two);
+               data->deleted = diff_filespec_size(one);
+       }
+       else if (complete_rewrite) {
                diff_populate_filespec(one, 0);
                diff_populate_filespec(two, 0);
                data->deleted = count_lines(one->data, one->size);
                data->added = count_lines(two->data, two->size);
-               goto free_and_return;
        }
-       if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
-               die("unable to read files to diff");
  
-       if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
-               data->is_binary = 1;
-               data->added = mf2.size;
-               data->deleted = mf1.size;
-       } else {
+       else {
                /* Crazy xdl interfaces.. */
                xpparam_t xpp;
                xdemitconf_t xecfg;
-               xdemitcb_t ecb;
+               if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
+                       die("unable to read files to diff");
  
                memset(&xpp, 0, sizeof(xpp));
                memset(&xecfg, 0, sizeof(xecfg));
-               xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
+               xpp.flags = o->xdl_opts;
                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
-                             &xpp, &xecfg, &ecb);
+                             &xpp, &xecfg);
        }
  
-  free_and_return:
        diff_free_filespec_data(one);
        diff_free_filespec_data(two);
  }
@@@ -1679,6 -2175,7 +2175,7 @@@ static void builtin_checkdiff(const cha
        data.lineno = 0;
        data.o = o;
        data.ws_rule = whitespace_rule(attr_path);
+       data.conflict_marker_size = ll_merge_marker_size(attr_path);
  
        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
                die("unable to read files to diff");
                /* Crazy xdl interfaces.. */
                xpparam_t xpp;
                xdemitconf_t xecfg;
-               xdemitcb_t ecb;
  
                memset(&xpp, 0, sizeof(xpp));
                memset(&xecfg, 0, sizeof(xecfg));
                xecfg.ctxlen = 1; /* at least one context line */
-               xpp.flags = XDF_NEED_MINIMAL;
+               xpp.flags = 0;
                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
-                             &xpp, &xecfg, &ecb);
-               if ((data.ws_rule & WS_TRAILING_SPACE) &&
-                   data.trailing_blanks_start) {
-                       fprintf(o->file, "%s:%d: ends with blank lines.\n",
-                               data.filename, data.trailing_blanks_start);
-                       data.status = 1; /* report errors */
+                             &xpp, &xecfg);
+               if (data.ws_rule & WS_BLANK_AT_EOF) {
+                       struct emit_callback ecbdata;
+                       int blank_at_eof;
+                       ecbdata.ws_rule = data.ws_rule;
+                       check_blank_at_eof(&mf1, &mf2, &ecbdata);
+                       blank_at_eof = ecbdata.blank_at_eof_in_postimage;
+                       if (blank_at_eof) {
+                               static char *err;
+                               if (!err)
+                                       err = whitespace_error_string(WS_BLANK_AT_EOF);
+                               fprintf(o->file, "%s:%d: %s.\n",
+                                       data.filename, blank_at_eof, err);
+                               data.status = 1; /* report errors */
+                       }
                }
        }
   free_and_return:
@@@ -1805,7 -2312,7 +2312,7 @@@ static int reuse_worktree_file(const ch
         * If ce is marked as "assume unchanged", there is no
         * guarantee that work tree matches what we are looking for.
         */
-       if (ce->ce_flags & CE_VALID)
+       if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
                return 0;
  
        /*
@@@ -1837,9 -2344,14 +2344,14 @@@ static int populate_from_stdin(struct d
  static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
  {
        int len;
-       char *data = xmalloc(100);
+       char *data = xmalloc(100), *dirty = "";
+       /* Are we looking at the work tree? */
+       if (s->dirty_submodule)
+               dirty = "-dirty";
        len = snprintf(data, 100,
-               "Subproject commit %s\n", sha1_to_hex(s->sha1));
+                      "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
        s->data = data;
        s->size = len;
        s->should_free = 1;
@@@ -1927,10 -2439,14 +2439,14 @@@ int diff_populate_filespec(struct diff_
        }
        else {
                enum object_type type;
-               if (size_only)
+               if (size_only) {
                        type = sha1_object_info(s->sha1, &s->size);
-               else {
+                       if (type < 0)
+                               die("unable to read %s", sha1_to_hex(s->sha1));
+               } else {
                        s->data = read_sha1_file(s->sha1, &type, &s->size);
+                       if (!s->data)
+                               die("unable to read %s", sha1_to_hex(s->sha1));
                        s->should_free = 1;
                }
        }
@@@ -2102,7 -2618,7 +2618,7 @@@ static void run_external_diff(const cha
        }
        *arg = NULL;
        fflush(NULL);
-       retval = run_command_v_opt(spawn_arg, 0);
+       retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
        remove_tempfile();
        if (retval) {
                fprintf(stderr, "external diff died, stopping at %s.\n", name);
@@@ -2121,36 -2637,53 +2637,53 @@@ static void fill_metainfo(struct strbu
                          struct diff_filespec *one,
                          struct diff_filespec *two,
                          struct diff_options *o,
-                         struct diff_filepair *p)
+                         struct diff_filepair *p,
+                         int *must_show_header,
+                         int use_color)
  {
+       const char *set = diff_get_color(use_color, DIFF_METAINFO);
+       const char *reset = diff_get_color(use_color, DIFF_RESET);
+       struct strbuf *msgbuf;
+       char *line_prefix = "";
+       *must_show_header = 1;
+       if (o->output_prefix) {
+               msgbuf = o->output_prefix(o, o->output_prefix_data);
+               line_prefix = msgbuf->buf;
+       }
        strbuf_init(msg, PATH_MAX * 2 + 300);
        switch (p->status) {
        case DIFF_STATUS_COPIED:
-               strbuf_addf(msg, "similarity index %d%%", similarity_index(p));
-               strbuf_addstr(msg, "\ncopy from ");
+               strbuf_addf(msg, "%s%ssimilarity index %d%%",
+                           line_prefix, set, similarity_index(p));
+               strbuf_addf(msg, "%s\n%s%scopy from ",
+                           reset,  line_prefix, set);
                quote_c_style(name, msg, NULL, 0);
-               strbuf_addstr(msg, "\ncopy to ");
+               strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
                quote_c_style(other, msg, NULL, 0);
-               strbuf_addch(msg, '\n');
+               strbuf_addf(msg, "%s\n", reset);
                break;
        case DIFF_STATUS_RENAMED:
-               strbuf_addf(msg, "similarity index %d%%", similarity_index(p));
-               strbuf_addstr(msg, "\nrename from ");
+               strbuf_addf(msg, "%s%ssimilarity index %d%%",
+                           line_prefix, set, similarity_index(p));
+               strbuf_addf(msg, "%s\n%s%srename from ",
+                           reset, line_prefix, set);
                quote_c_style(name, msg, NULL, 0);
-               strbuf_addstr(msg, "\nrename to ");
+               strbuf_addf(msg, "%s\n%s%srename to ",
+                           reset, line_prefix, set);
                quote_c_style(other, msg, NULL, 0);
-               strbuf_addch(msg, '\n');
+               strbuf_addf(msg, "%s\n", reset);
                break;
        case DIFF_STATUS_MODIFIED:
                if (p->score) {
-                       strbuf_addf(msg, "dissimilarity index %d%%\n",
-                                   similarity_index(p));
+                       strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
+                                   line_prefix,
+                                   set, similarity_index(p), reset);
                        break;
                }
                /* fallthru */
        default:
-               /* nothing */
-               ;
+               *must_show_header = 0;
        }
        if (one && two && hashcmp(one->sha1, two->sha1)) {
                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
                                abbrev = 40;
                }
-               strbuf_addf(msg, "index %.*s..%.*s",
-                           abbrev, sha1_to_hex(one->sha1),
-                           abbrev, sha1_to_hex(two->sha1));
+               strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
+                           find_unique_abbrev(one->sha1, abbrev));
+               strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
                if (one->mode == two->mode)
                        strbuf_addf(msg, " %06o", one->mode);
-               strbuf_addch(msg, '\n');
+               strbuf_addf(msg, "%s\n", reset);
        }
-       if (msg->len)
-               strbuf_setlen(msg, msg->len - 1);
  }
  
  static void run_diff_cmd(const char *pgm,
  {
        const char *xfrm_msg = NULL;
        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
-       if (msg) {
-               fill_metainfo(msg, name, other, one, two, o, p);
-               xfrm_msg = msg->len ? msg->buf : NULL;
-       }
+       int must_show_header = 0;
  
        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
                pgm = NULL;
                        pgm = drv->external;
        }
  
+       if (msg) {
+               /*
+                * don't use colors when the header is intended for an
+                * external diff driver
+                */
+               fill_metainfo(msg, name, other, one, two, o, p,
+                             &must_show_header,
+                             DIFF_OPT_TST(o, COLOR_DIFF) && !pgm);
+               xfrm_msg = msg->len ? msg->buf : NULL;
+       }
        if (pgm) {
                run_external_diff(pgm, name, other, one, two, xfrm_msg,
                                  complete_rewrite);
        }
        if (one && two)
                builtin_diff(name, other ? other : name,
-                            one, two, xfrm_msg, o, complete_rewrite);
+                            one, two, xfrm_msg, must_show_header,
+                            o, complete_rewrite);
        else
                fprintf(o->file, "* Unmerged path %s\n", name);
  }
@@@ -2232,10 -2771,16 +2771,16 @@@ static void diff_fill_sha1_info(struct 
  static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
  {
        /* Strip the prefix but do not molest /dev/null and absolute paths */
-       if (*namep && **namep != '/')
+       if (*namep && **namep != '/') {
                *namep += prefix_length;
-       if (*otherp && **otherp != '/')
+               if (**namep == '/')
+                       ++*namep;
+       }
+       if (*otherp && **otherp != '/') {
                *otherp += prefix_length;
+               if (**otherp == '/')
+                       ++*otherp;
+       }
  }
  
  static void run_diff(struct diff_filepair *p, struct diff_options *o)
@@@ -2341,7 -2886,7 +2886,7 @@@ static void run_checkdiff(struct diff_f
  
  void diff_setup(struct diff_options *options)
  {
-       memset(options, 0, sizeof(*options));
+       memcpy(options, &default_diff_options, sizeof(*options));
  
        options->file = stdout;
  
                DIFF_OPT_SET(options, COLOR_DIFF);
        options->detect_rename = diff_detect_rename_default;
  
-       if (!diff_mnemonic_prefix) {
+       if (diff_no_prefix) {
+               options->a_prefix = options->b_prefix = "";
+       } else if (!diff_mnemonic_prefix) {
                options->a_prefix = "a/";
                options->b_prefix = "b/";
        }
@@@ -2382,7 -2929,7 +2929,7 @@@ int diff_setup_done(struct diff_option
         * Most of the time we can say "there are changes"
         * only by checking if there are changed paths, but
         * --ignore-whitespace* options force us to look
-        * inside contets.
+        * inside contents.
         */
  
        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
         */
        if (options->pickaxe)
                DIFF_OPT_SET(options, RECURSIVE);
+       /*
+        * When patches are generated, submodules diffed against the work tree
+        * must be checked for dirtiness too so it can be shown in the output
+        */
+       if (options->output_format & DIFF_FORMAT_PATCH)
+               DIFF_OPT_SET(options, DIRTY_SUBMODULES);
  
        if (options->detect_rename && options->rename_limit < 0)
                options->rename_limit = diff_rename_limit_default;
@@@ -2509,12 -3062,103 +3062,103 @@@ static int opt_arg(const char *arg, in
  
  static int diff_scoreopt_parse(const char *opt);
  
+ static inline int short_opt(char opt, const char **argv,
+                           const char **optarg)
+ {
+       const char *arg = argv[0];
+       if (arg[0] != '-' || arg[1] != opt)
+               return 0;
+       if (arg[2] != '\0') {
+               *optarg = arg + 2;
+               return 1;
+       }
+       if (!argv[1])
+               die("Option '%c' requires a value", opt);
+       *optarg = argv[1];
+       return 2;
+ }
+ int parse_long_opt(const char *opt, const char **argv,
+                  const char **optarg)
+ {
+       const char *arg = argv[0];
+       if (arg[0] != '-' || arg[1] != '-')
+               return 0;
+       arg += strlen("--");
+       if (prefixcmp(arg, opt))
+               return 0;
+       arg += strlen(opt);
+       if (*arg == '=') { /* sticked form: --option=value */
+               *optarg = arg + 1;
+               return 1;
+       }
+       if (*arg != '\0')
+               return 0;
+       /* separate form: --option value */
+       if (!argv[1])
+               die("Option '--%s' requires a value", opt);
+       *optarg = argv[1];
+       return 2;
+ }
+ static int stat_opt(struct diff_options *options, const char **av)
+ {
+       const char *arg = av[0];
+       char *end;
+       int width = options->stat_width;
+       int name_width = options->stat_name_width;
+       int argcount = 1;
+       arg += strlen("--stat");
+       end = (char *)arg;
+       switch (*arg) {
+       case '-':
+               if (!prefixcmp(arg, "-width")) {
+                       arg += strlen("-width");
+                       if (*arg == '=')
+                               width = strtoul(arg + 1, &end, 10);
+                       else if (!*arg && !av[1])
+                               die("Option '--stat-width' requires a value");
+                       else if (!*arg) {
+                               width = strtoul(av[1], &end, 10);
+                               argcount = 2;
+                       }
+               } else if (!prefixcmp(arg, "-name-width")) {
+                       arg += strlen("-name-width");
+                       if (*arg == '=')
+                               name_width = strtoul(arg + 1, &end, 10);
+                       else if (!*arg && !av[1])
+                               die("Option '--stat-name-width' requires a value");
+                       else if (!*arg) {
+                               name_width = strtoul(av[1], &end, 10);
+                               argcount = 2;
+                       }
+               }
+               break;
+       case '=':
+               width = strtoul(arg+1, &end, 10);
+               if (*end == ',')
+                       name_width = strtoul(end+1, &end, 10);
+       }
+       /* Important! This checks all the error cases! */
+       if (*end)
+               return 0;
+       options->output_format |= DIFF_FORMAT_DIFFSTAT;
+       options->stat_name_width = name_width;
+       options->stat_width = width;
+       return argcount;
+ }
  int diff_opt_parse(struct diff_options *options, const char **av, int ac)
  {
        const char *arg = av[0];
+       const char *optarg;
+       int argcount;
  
        /* Output format options */
-       if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
+       if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
                options->output_format |= DIFF_FORMAT_PATCH;
        else if (opt_arg(arg, 'U', "unified", &options->context))
                options->output_format |= DIFF_FORMAT_PATCH;
                options->output_format |= DIFF_FORMAT_NAME_STATUS;
        else if (!strcmp(arg, "-s"))
                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
-       else if (!prefixcmp(arg, "--stat")) {
-               char *end;
-               int width = options->stat_width;
-               int name_width = options->stat_name_width;
-               arg += 6;
-               end = (char *)arg;
-               switch (*arg) {
-               case '-':
-                       if (!prefixcmp(arg, "-width="))
-                               width = strtoul(arg + 7, &end, 10);
-                       else if (!prefixcmp(arg, "-name-width="))
-                               name_width = strtoul(arg + 12, &end, 10);
-                       break;
-               case '=':
-                       width = strtoul(arg+1, &end, 10);
-                       if (*end == ',')
-                               name_width = strtoul(end+1, &end, 10);
-               }
-               /* Important! This checks all the error cases! */
-               if (*end)
-                       return 0;
-               options->output_format |= DIFF_FORMAT_DIFFSTAT;
-               options->stat_name_width = name_width;
-               options->stat_width = width;
-       }
+       else if (!prefixcmp(arg, "--stat"))
+               /* --stat, --stat-width, or --stat-name-width */
+               return stat_opt(options, av);
  
        /* renames options */
-       else if (!prefixcmp(arg, "-B")) {
+       else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
+                !strcmp(arg, "--break-rewrites")) {
                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
-                       return -1;
+                       return error("invalid argument to -B: %s", arg+2);
        }
-       else if (!prefixcmp(arg, "-M")) {
+       else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
+                !strcmp(arg, "--find-renames")) {
                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
-                       return -1;
+                       return error("invalid argument to -M: %s", arg+2);
                options->detect_rename = DIFF_DETECT_RENAME;
        }
-       else if (!prefixcmp(arg, "-C")) {
+       else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
+                !strcmp(arg, "--find-copies")) {
                if (options->detect_rename == DIFF_DETECT_COPY)
                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
-                       return -1;
+                       return error("invalid argument to -C: %s", arg+2);
                options->detect_rename = DIFF_DETECT_COPY;
        }
        else if (!strcmp(arg, "--no-renames"))
                DIFF_OPT_SET(options, FOLLOW_RENAMES);
        else if (!strcmp(arg, "--color"))
                DIFF_OPT_SET(options, COLOR_DIFF);
+       else if (!prefixcmp(arg, "--color=")) {
+               int value = git_config_colorbool(NULL, arg+8, -1);
+               if (value == 0)
+                       DIFF_OPT_CLR(options, COLOR_DIFF);
+               else if (value > 0)
+                       DIFF_OPT_SET(options, COLOR_DIFF);
+               else
+                       return error("option `color' expects \"always\", \"auto\", or \"never\"");
+       }
        else if (!strcmp(arg, "--no-color"))
                DIFF_OPT_CLR(options, COLOR_DIFF);
        else if (!strcmp(arg, "--color-words")) {
                DIFF_OPT_SET(options, COLOR_DIFF);
-               DIFF_OPT_SET(options, COLOR_DIFF_WORDS);
+               options->word_diff = DIFF_WORDS_COLOR;
        }
        else if (!prefixcmp(arg, "--color-words=")) {
                DIFF_OPT_SET(options, COLOR_DIFF);
-               DIFF_OPT_SET(options, COLOR_DIFF_WORDS);
+               options->word_diff = DIFF_WORDS_COLOR;
                options->word_regex = arg + 14;
        }
+       else if (!strcmp(arg, "--word-diff")) {
+               if (options->word_diff == DIFF_WORDS_NONE)
+                       options->word_diff = DIFF_WORDS_PLAIN;
+       }
+       else if (!prefixcmp(arg, "--word-diff=")) {
+               const char *type = arg + 12;
+               if (!strcmp(type, "plain"))
+                       options->word_diff = DIFF_WORDS_PLAIN;
+               else if (!strcmp(type, "color")) {
+                       DIFF_OPT_SET(options, COLOR_DIFF);
+                       options->word_diff = DIFF_WORDS_COLOR;
+               }
+               else if (!strcmp(type, "porcelain"))
+                       options->word_diff = DIFF_WORDS_PORCELAIN;
+               else if (!strcmp(type, "none"))
+                       options->word_diff = DIFF_WORDS_NONE;
+               else
+                       die("bad --word-diff argument: %s", type);
+       }
+       else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
+               if (options->word_diff == DIFF_WORDS_NONE)
+                       options->word_diff = DIFF_WORDS_PLAIN;
+               options->word_regex = optarg;
+               return argcount;
+       }
        else if (!strcmp(arg, "--exit-code"))
                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
        else if (!strcmp(arg, "--quiet"))
                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
        else if (!strcmp(arg, "--no-textconv"))
                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
-       else if (!strcmp(arg, "--ignore-submodules"))
-               DIFF_OPT_SET(options, IGNORE_SUBMODULES);
+       else if (!strcmp(arg, "--ignore-submodules")) {
+               DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
+               handle_ignore_submodules_arg(options, "all");
+       } else if (!prefixcmp(arg, "--ignore-submodules=")) {
+               DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
+               handle_ignore_submodules_arg(options, arg + 20);
+       } else if (!strcmp(arg, "--submodule"))
+               DIFF_OPT_SET(options, SUBMODULE_LOG);
+       else if (!prefixcmp(arg, "--submodule=")) {
+               if (!strcmp(arg + 12, "log"))
+                       DIFF_OPT_SET(options, SUBMODULE_LOG);
+       }
  
        /* misc options */
        else if (!strcmp(arg, "-z"))
                options->line_termination = 0;
-       else if (!prefixcmp(arg, "-l"))
-               options->rename_limit = strtoul(arg+2, NULL, 10);
-       else if (!prefixcmp(arg, "-S"))
-               options->pickaxe = arg + 2;
+       else if ((argcount = short_opt('l', av, &optarg))) {
+               options->rename_limit = strtoul(optarg, NULL, 10);
+               return argcount;
+       }
+       else if ((argcount = short_opt('S', av, &optarg))) {
+               options->pickaxe = optarg;
+               options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
+               return argcount;
+       } else if ((argcount = short_opt('G', av, &optarg))) {
+               options->pickaxe = optarg;
+               options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
+               return argcount;
+       }
        else if (!strcmp(arg, "--pickaxe-all"))
-               options->pickaxe_opts = DIFF_PICKAXE_ALL;
+               options->pickaxe_opts |= DIFF_PICKAXE_ALL;
        else if (!strcmp(arg, "--pickaxe-regex"))
-               options->pickaxe_opts = DIFF_PICKAXE_REGEX;
-       else if (!prefixcmp(arg, "-O"))
-               options->orderfile = arg + 2;
-       else if (!prefixcmp(arg, "--diff-filter="))
-               options->filter = arg + 14;
+               options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
+       else if ((argcount = short_opt('O', av, &optarg))) {
+               options->orderfile = optarg;
+               return argcount;
+       }
+       else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
+               options->filter = optarg;
+               return argcount;
+       }
        else if (!strcmp(arg, "--abbrev"))
                options->abbrev = DEFAULT_ABBREV;
        else if (!prefixcmp(arg, "--abbrev=")) {
                else if (40 < options->abbrev)
                        options->abbrev = 40;
        }
-       else if (!prefixcmp(arg, "--src-prefix="))
-               options->a_prefix = arg + 13;
-       else if (!prefixcmp(arg, "--dst-prefix="))
-               options->b_prefix = arg + 13;
+       else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
+               options->a_prefix = optarg;
+               return argcount;
+       }
+       else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
+               options->b_prefix = optarg;
+               return argcount;
+       }
        else if (!strcmp(arg, "--no-prefix"))
                options->a_prefix = options->b_prefix = "";
        else if (opt_arg(arg, '\0', "inter-hunk-context",
                         &options->interhunkcontext))
                ;
-       else if (!prefixcmp(arg, "--output=")) {
-               options->file = fopen(arg + strlen("--output="), "w");
+       else if ((argcount = parse_long_opt("output", av, &optarg))) {
+               options->file = fopen(optarg, "w");
+               if (!options->file)
+                       die_errno("Could not open '%s'", optarg);
                options->close_file = 1;
+               return argcount;
        } else
                return 0;
        return 1;
  }
  
static int parse_num(const char **cp_p)
int parse_rename_score(const char **cp_p)
  {
        unsigned long num, scale;
        int ch, dot;
        num = 0;
        scale = 1;
        dot = 0;
-       for(;;) {
+       for (;;) {
                ch = *cp;
                if ( !dot && ch == '.' ) {
                        scale = 1;
@@@ -2739,10 -3426,26 +3426,26 @@@ static int diff_scoreopt_parse(const ch
        if (*opt++ != '-')
                return -1;
        cmd = *opt++;
+       if (cmd == '-') {
+               /* convert the long-form arguments into short-form versions */
+               if (!prefixcmp(opt, "break-rewrites")) {
+                       opt += strlen("break-rewrites");
+                       if (*opt == 0 || *opt++ == '=')
+                               cmd = 'B';
+               } else if (!prefixcmp(opt, "find-copies")) {
+                       opt += strlen("find-copies");
+                       if (*opt == 0 || *opt++ == '=')
+                               cmd = 'C';
+               } else if (!prefixcmp(opt, "find-renames")) {
+                       opt += strlen("find-renames");
+                       if (*opt == 0 || *opt++ == '=')
+                               cmd = 'M';
+               }
+       }
        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
                return -1; /* that is not a -M, -C nor -B option */
  
-       opt1 = parse_num(&opt);
+       opt1 = parse_rename_score(&opt);
        if (cmd != 'B')
                opt2 = 0;
        else {
                        return -1; /* we expect -B80/99 or -B80 */
                else {
                        opt++;
-                       opt2 = parse_num(&opt);
+                       opt2 = parse_rename_score(&opt);
                }
        }
        if (*opt != 0)
@@@ -2818,6 -3521,11 +3521,11 @@@ static void diff_flush_raw(struct diff_
  {
        int line_termination = opt->line_termination;
        int inter_name_termination = line_termination ? '\t' : '\0';
+       if (opt->output_prefix) {
+               struct strbuf *msg = NULL;
+               msg = opt->output_prefix(opt, opt->output_prefix_data);
+               fprintf(opt->file, "%s", msg->buf);
+       }
  
        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
@@@ -2872,7 -3580,8 +3580,8 @@@ int diff_unmodified_pair(struct diff_fi
         * dealing with a change.
         */
        if (one->sha1_valid && two->sha1_valid &&
-           !hashcmp(one->sha1, two->sha1))
+           !hashcmp(one->sha1, two->sha1) &&
+           !one->dirty_submodule && !two->dirty_submodule)
                return 1; /* no change */
        if (!one->sha1_valid && !two->sha1_valid)
                return 1; /* both look at the same file on the filesystem. */
@@@ -2899,7 -3608,7 +3608,7 @@@ static void diff_flush_stat(struct diff
  
        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
-               return; /* no tree diffs in patch format */
+               return; /* no useful stat for tree diffs */
  
        run_diffstat(p, o, diffstat);
  }
@@@ -2912,7 -3621,7 +3621,7 @@@ static void diff_flush_checkdiff(struc
  
        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
-               return; /* no tree diffs in patch format */
+               return; /* nothing to check in tree diffs */
  
        run_checkdiff(p, o);
  }
@@@ -3007,6 -3716,8 +3716,8 @@@ static void diff_resolve_rename_copy(vo
                }
                else if (hashcmp(p->one->sha1, p->two->sha1) ||
                         p->one->mode != p->two->mode ||
+                        p->one->dirty_submodule ||
+                        p->two->dirty_submodule ||
                         is_null_sha1(p->one->sha1))
                        p->status = DIFF_STATUS_MODIFIED;
                else {
@@@ -3060,48 -3771,62 +3771,62 @@@ static void show_file_mode_name(FILE *f
  }
  
  
- static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
+ static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
+               const char *line_prefix)
  {
        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
-               fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
-                       show_name ? ' ' : '\n');
+               fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
+                       p->two->mode, show_name ? ' ' : '\n');
                if (show_name) {
                        write_name_quoted(p->two->path, file, '\n');
                }
        }
  }
  
- static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
+ static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
+                       const char *line_prefix)
  {
        char *names = pprint_rename(p->one->path, p->two->path);
  
        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
        free(names);
-       show_mode_change(file, p, 0);
+       show_mode_change(file, p, 0, line_prefix);
  }
  
- static void diff_summary(FILE *file, struct diff_filepair *p)
+ static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
  {
+       FILE *file = opt->file;
+       char *line_prefix = "";
+       if (opt->output_prefix) {
+               struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
+               line_prefix = buf->buf;
+       }
        switch(p->status) {
        case DIFF_STATUS_DELETED:
+               fputs(line_prefix, file);
                show_file_mode_name(file, "delete", p->one);
                break;
        case DIFF_STATUS_ADDED:
+               fputs(line_prefix, file);
                show_file_mode_name(file, "create", p->two);
                break;
        case DIFF_STATUS_COPIED:
-               show_rename_copy(file, "copy", p);
+               fputs(line_prefix, file);
+               show_rename_copy(file, "copy", p, line_prefix);
                break;
        case DIFF_STATUS_RENAMED:
-               show_rename_copy(file, "rename", p);
+               fputs(line_prefix, file);
+               show_rename_copy(file, "rename", p, line_prefix);
                break;
        default:
                if (p->score) {
-                       fputs(" rewrite ", file);
+                       fprintf(file, "%s rewrite ", line_prefix);
                        write_name_quoted(p->two->path, file, ' ');
                        fprintf(file, "(%d%%)\n", similarity_index(p));
                }
-               show_mode_change(file, p, !p->score);
+               show_mode_change(file, p, !p->score, line_prefix);
                break;
        }
  }
@@@ -3155,7 -3880,6 +3880,6 @@@ static int diff_get_patch_id(struct dif
        for (i = 0; i < q->nr; i++) {
                xpparam_t xpp;
                xdemitconf_t xecfg;
-               xdemitcb_t ecb;
                mmfile_t mf1, mf2;
                struct diff_filepair *p = q->queue[i];
                int len1, len2;
                                        len2, p->two->path);
                git_SHA1_Update(&ctx, buffer, len1);
  
-               xpp.flags = XDF_NEED_MINIMAL;
+               if (diff_filespec_is_binary(p->one) ||
+                   diff_filespec_is_binary(p->two)) {
+                       git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
+                       git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
+                       continue;
+               }
+               xpp.flags = 0;
                xecfg.ctxlen = 3;
-               xecfg.flags = XDL_EMIT_FUNCNAMES;
+               xecfg.flags = 0;
                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
-                             &xpp, &xecfg, &ecb);
+                             &xpp, &xecfg);
        }
  
        git_SHA1_Final(sha1, &ctx);
@@@ -3234,8 -3965,7 +3965,7 @@@ int diff_flush_patch_id(struct diff_opt
                diff_free_filepair(q->queue[i]);
  
        free(q->queue);
-       q->queue = NULL;
-       q->nr = q->alloc = 0;
+       DIFF_QUEUE_CLEAR(q);
  
        return result;
  }
@@@ -3312,11 -4042,35 +4042,35 @@@ void diff_flush(struct diff_options *op
                show_dirstat(options);
  
        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
-               for (i = 0; i < q->nr; i++)
-                       diff_summary(options->file, q->queue[i]);
+               for (i = 0; i < q->nr; i++) {
+                       diff_summary(options, q->queue[i]);
+               }
                separator++;
        }
  
+       if (output_format & DIFF_FORMAT_NO_OUTPUT &&
+           DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
+           DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
+               /*
+                * run diff_flush_patch for the exit status. setting
+                * options->file to /dev/null should be safe, becaue we
+                * aren't supposed to produce any output anyway.
+                */
+               if (options->close_file)
+                       fclose(options->file);
+               options->file = fopen("/dev/null", "w");
+               if (!options->file)
+                       die_errno("Could not open /dev/null");
+               options->close_file = 1;
+               for (i = 0; i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+                       if (check_pair_status(p))
+                               diff_flush_patch(p, options);
+                       if (options->found_changes)
+                               break;
+               }
+       }
        if (output_format & DIFF_FORMAT_PATCH) {
                if (separator) {
                        putc(options->line_termination, options->file);
                diff_free_filepair(q->queue[i]);
  free_queue:
        free(q->queue);
-       q->queue = NULL;
-       q->nr = q->alloc = 0;
+       DIFF_QUEUE_CLEAR(q);
        if (options->close_file)
                fclose(options->file);
  
        /*
-        * Report the contentlevel differences with HAS_CHANGES;
+        * Report the content-level differences with HAS_CHANGES;
         * diff_addremove/diff_change does not set the bit when
         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
         */
@@@ -3363,8 -4116,7 +4116,7 @@@ static void diffcore_apply_filter(cons
        int i;
        struct diff_queue_struct *q = &diff_queued_diff;
        struct diff_queue_struct outq;
-       outq.queue = NULL;
-       outq.nr = outq.alloc = 0;
+       DIFF_QUEUE_CLEAR(&outq);
  
        if (!filter)
                return;
@@@ -3432,14 -4184,13 +4184,13 @@@ static void diffcore_skip_stat_unmatch(
        int i;
        struct diff_queue_struct *q = &diff_queued_diff;
        struct diff_queue_struct outq;
-       outq.queue = NULL;
-       outq.nr = outq.alloc = 0;
+       DIFF_QUEUE_CLEAR(&outq);
  
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
  
                /*
-                * 1. Entries that come from stat info dirtyness
+                * 1. Entries that come from stat info dirtiness
                 *    always have both sides (iow, not create/delete),
                 *    one side of the object name is unknown, with
                 *    the same mode and size.  Keep the ones that
        *q = outq;
  }
  
+ static int diffnamecmp(const void *a_, const void *b_)
+ {
+       const struct diff_filepair *a = *((const struct diff_filepair **)a_);
+       const struct diff_filepair *b = *((const struct diff_filepair **)b_);
+       const char *name_a, *name_b;
+       name_a = a->one ? a->one->path : a->two->path;
+       name_b = b->one ? b->one->path : b->two->path;
+       return strcmp(name_a, name_b);
+ }
+ void diffcore_fix_diff_index(struct diff_options *options)
+ {
+       struct diff_queue_struct *q = &diff_queued_diff;
+       qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
+ }
  void diffcore_std(struct diff_options *options)
  {
        if (options->skip_stat_unmatch)
                diffcore_skip_stat_unmatch(options);
-       if (options->break_opt != -1)
-               diffcore_break(options->break_opt);
-       if (options->detect_rename)
-               diffcore_rename(options);
-       if (options->break_opt != -1)
-               diffcore_merge_broken();
+       if (!options->found_follow) {
+               /* See try_to_follow_renames() in tree-diff.c */
+               if (options->break_opt != -1)
+                       diffcore_break(options->break_opt);
+               if (options->detect_rename)
+                       diffcore_rename(options);
+               if (options->break_opt != -1)
+                       diffcore_merge_broken();
+       }
        if (options->pickaxe)
-               diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
+               diffcore_pickaxe(options);
        if (options->orderfile)
                diffcore_order(options->orderfile);
-       diff_resolve_rename_copy();
+       if (!options->found_follow)
+               /* See try_to_follow_renames() in tree-diff.c */
+               diff_resolve_rename_copy();
        diffcore_apply_filter(options->filter);
  
        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
                DIFF_OPT_SET(options, HAS_CHANGES);
        else
                DIFF_OPT_CLR(options, HAS_CHANGES);
+       options->found_follow = 0;
  }
  
  int diff_result_code(struct diff_options *opt, int status)
        return result;
  }
  
 +int diff_can_quit_early(struct diff_options *opt)
 +{
 +      return (DIFF_OPT_TST(opt, QUICK) &&
 +              !opt->filter &&
 +              DIFF_OPT_TST(opt, HAS_CHANGES));
 +}
 +
+ /*
+  * Shall changes to this submodule be ignored?
+  *
+  * Submodule changes can be configured to be ignored separately for each path,
+  * but that configuration can be overridden from the command line.
+  */
+ static int is_submodule_ignored(const char *path, struct diff_options *options)
+ {
+       int ignored = 0;
+       unsigned orig_flags = options->flags;
+       if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
+               set_diffopt_flags_from_submodule_config(options, path);
+       if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
+               ignored = 1;
+       options->flags = orig_flags;
+       return ignored;
+ }
  void diff_addremove(struct diff_options *options,
                    int addremove, unsigned mode,
                    const unsigned char *sha1,
-                   const char *concatpath)
+                   const char *concatpath, unsigned dirty_submodule)
  {
        struct diff_filespec *one, *two;
  
-       if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
+       if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
                return;
  
        /* This may look odd, but it is a preparation for
  
        if (addremove != '+')
                fill_filespec(one, sha1, mode);
-       if (addremove != '-')
+       if (addremove != '-') {
                fill_filespec(two, sha1, mode);
+               two->dirty_submodule = dirty_submodule;
+       }
  
        diff_queue(&diff_queued_diff, one, two);
        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
@@@ -3567,12 -4355,13 +4362,13 @@@ void diff_change(struct diff_options *o
                 unsigned old_mode, unsigned new_mode,
                 const unsigned char *old_sha1,
                 const unsigned char *new_sha1,
-                const char *concatpath)
+                const char *concatpath,
+                unsigned old_dirty_submodule, unsigned new_dirty_submodule)
  {
        struct diff_filespec *one, *two;
  
-       if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
-                       && S_ISGITLINK(new_mode))
+       if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
+           is_submodule_ignored(concatpath, options))
                return;
  
        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
                const unsigned char *tmp_c;
                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
+               tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
+                       new_dirty_submodule = tmp;
        }
  
        if (options->prefix &&
        two = alloc_filespec(concatpath);
        fill_filespec(one, old_sha1, old_mode);
        fill_filespec(two, new_sha1, new_mode);
+       one->dirty_submodule = old_dirty_submodule;
+       two->dirty_submodule = new_dirty_submodule;
  
        diff_queue(&diff_queued_diff, one, two);
        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
                DIFF_OPT_SET(options, HAS_CHANGES);
  }
  
- void diff_unmerge(struct diff_options *options,
-                 const char *path,
-                 unsigned mode, const unsigned char *sha1)
+ struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
  {
+       struct diff_filepair *pair;
        struct diff_filespec *one, *two;
  
        if (options->prefix &&
            strncmp(path, options->prefix, options->prefix_length))
-               return;
+               return NULL;
  
        one = alloc_filespec(path);
        two = alloc_filespec(path);
-       fill_filespec(one, sha1, mode);
-       diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
+       pair = diff_queue(&diff_queued_diff, one, two);
+       pair->is_unmerged = 1;
+       return pair;
  }
  
  static char *run_textconv(const char *pgm, struct diff_filespec *spec,
        const char **arg = argv;
        struct child_process child;
        struct strbuf buf = STRBUF_INIT;
+       int err = 0;
  
        temp = prepare_temp_file(spec->path, spec);
        *arg++ = pgm;
        *arg = NULL;
  
        memset(&child, 0, sizeof(child));
+       child.use_shell = 1;
        child.argv = argv;
        child.out = -1;
-       if (start_command(&child) != 0 ||
-           strbuf_read(&buf, child.out, 0) < 0 ||
-           finish_command(&child) != 0) {
+       if (start_command(&child)) {
+               remove_tempfile();
+               return NULL;
+       }
+       if (strbuf_read(&buf, child.out, 0) < 0)
+               err = error("error reading from textconv command '%s'", pgm);
+       close(child.out);
+       if (finish_command(&child) || err) {
                strbuf_release(&buf);
                remove_tempfile();
-               error("error running textconv command '%s'", pgm);
                return NULL;
        }
        remove_tempfile();
  
        return strbuf_detach(&buf, outsize);
  }
+ size_t fill_textconv(struct userdiff_driver *driver,
+                    struct diff_filespec *df,
+                    char **outbuf)
+ {
+       size_t size;
+       if (!driver || !driver->textconv) {
+               if (!DIFF_FILE_VALID(df)) {
+                       *outbuf = "";
+                       return 0;
+               }
+               if (diff_populate_filespec(df, 0))
+                       die("unable to read files to diff");
+               *outbuf = df->data;
+               return df->size;
+       }
+       if (driver->textconv_cache && df->sha1_valid) {
+               *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
+                                         &size);
+               if (*outbuf)
+                       return size;
+       }
+       *outbuf = run_textconv(driver->textconv, df, &size);
+       if (!*outbuf)
+               die("unable to read files to diff");
+       if (driver->textconv_cache && df->sha1_valid) {
+               /* ignore errors, as we might be in a readonly repository */
+               notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
+                               size);
+               /*
+                * we could save up changes and flush them all at the end,
+                * but we would need an extra call after all diffing is done.
+                * Since generating a cache entry is the slow path anyway,
+                * this extra overhead probably isn't a big deal.
+                */
+               notes_cache_write(driver->textconv_cache);
+       }
+       return size;
+ }
diff --combined diff.h
index b412ffb9705c64e19841f89d6f9580afd51a1c7d,42b49d8f228fd2cc680ab9a2e332819d46f2f875..394765dd381fb3056252c4cba3a44c911ea5f108
--- 1/diff.h
--- 2/diff.h
+++ b/diff.h
@@@ -9,21 -9,27 +9,27 @@@
  struct rev_info;
  struct diff_options;
  struct diff_queue_struct;
+ struct strbuf;
+ struct diff_filespec;
+ struct userdiff_driver;
  
  typedef void (*change_fn_t)(struct diff_options *options,
                 unsigned old_mode, unsigned new_mode,
                 const unsigned char *old_sha1,
                 const unsigned char *new_sha1,
-                const char *fullpath);
+                const char *fullpath,
+                unsigned old_dirty_submodule, unsigned new_dirty_submodule);
  
  typedef void (*add_remove_fn_t)(struct diff_options *options,
                    int addremove, unsigned mode,
                    const unsigned char *sha1,
-                   const char *fullpath);
+                   const char *fullpath, unsigned dirty_submodule);
  
  typedef void (*diff_format_fn_t)(struct diff_queue_struct *q,
                struct diff_options *options, void *data);
  
+ typedef struct strbuf *(*diff_prefix_fn_t)(struct diff_options *opt, void *data);
  #define DIFF_FORMAT_RAW               0x0001
  #define DIFF_FORMAT_DIFFSTAT  0x0002
  #define DIFF_FORMAT_NUMSTAT   0x0004
@@@ -53,7 -59,7 +59,7 @@@
  #define DIFF_OPT_FIND_COPIES_HARDER  (1 <<  6)
  #define DIFF_OPT_FOLLOW_RENAMES      (1 <<  7)
  #define DIFF_OPT_COLOR_DIFF          (1 <<  8)
- #define DIFF_OPT_COLOR_DIFF_WORDS    (1 <<  9)
+ /* (1 <<  9) unused */
  #define DIFF_OPT_HAS_CHANGES         (1 << 10)
  #define DIFF_OPT_QUICK               (1 << 11)
  #define DIFF_OPT_NO_INDEX            (1 << 12)
  #define DIFF_OPT_DIRSTAT_BY_FILE     (1 << 20)
  #define DIFF_OPT_ALLOW_TEXTCONV      (1 << 21)
  #define DIFF_OPT_DIFF_FROM_CONTENTS  (1 << 22)
+ #define DIFF_OPT_SUBMODULE_LOG       (1 << 23)
+ #define DIFF_OPT_DIRTY_SUBMODULES    (1 << 24)
+ #define DIFF_OPT_IGNORE_UNTRACKED_IN_SUBMODULES (1 << 25)
+ #define DIFF_OPT_IGNORE_DIRTY_SUBMODULES (1 << 26)
+ #define DIFF_OPT_OVERRIDE_SUBMODULE_CONFIG (1 << 27)
  #define DIFF_OPT_TST(opts, flag)    ((opts)->flags & DIFF_OPT_##flag)
  #define DIFF_OPT_SET(opts, flag)    ((opts)->flags |= DIFF_OPT_##flag)
  #define DIFF_OPT_CLR(opts, flag)    ((opts)->flags &= ~DIFF_OPT_##flag)
  #define DIFF_XDL_SET(opts, flag)    ((opts)->xdl_opts |= XDF_##flag)
  #define DIFF_XDL_CLR(opts, flag)    ((opts)->xdl_opts &= ~XDF_##flag)
  
+ enum diff_words_type {
+       DIFF_WORDS_NONE = 0,
+       DIFF_WORDS_PORCELAIN,
+       DIFF_WORDS_PLAIN,
+       DIFF_WORDS_COLOR
+ };
  struct diff_options {
        const char *filter;
        const char *orderfile;
        int pickaxe_opts;
        int rename_score;
        int rename_limit;
-       int warn_on_too_large_rename;
+       int needed_rename_limit;
+       int show_rename_progress;
        int dirstat_percent;
        int setup;
        int abbrev;
        int stat_width;
        int stat_name_width;
        const char *word_regex;
+       enum diff_words_type word_diff;
  
        /* this is set by diffcore for DIFF_FORMAT_PATCH */
        int found_changes;
  
+       /* to support internal diff recursion by --follow hack*/
+       int found_follow;
        FILE *file;
        int close_file;
  
-       int nr_paths;
-       const char **paths;
-       int *pathlens;
+       struct pathspec pathspec;
        change_fn_t change;
        add_remove_fn_t add_remove;
        diff_format_fn_t format_callback;
        void *format_callback_data;
+       diff_prefix_fn_t output_prefix;
+       void *output_prefix_data;
  };
  
  enum color_diff {
        DIFF_FILE_NEW = 5,
        DIFF_COMMIT = 6,
        DIFF_WHITESPACE = 7,
+       DIFF_FUNCINFO = 8
  };
  const char *diff_get_color(int diff_use_color, enum color_diff ix);
  #define diff_get_color_opt(o, ix) \
@@@ -170,29 -195,32 +195,34 @@@ extern void diff_tree_combined_merge(co
  
  void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b);
  
 +extern int diff_can_quit_early(struct diff_options *);
 +
  extern void diff_addremove(struct diff_options *,
                           int addremove,
                           unsigned mode,
                           const unsigned char *sha1,
-                          const char *fullpath);
+                          const char *fullpath, unsigned dirty_submodule);
  
  extern void diff_change(struct diff_options *,
                        unsigned mode1, unsigned mode2,
                        const unsigned char *sha1,
                        const unsigned char *sha2,
-                       const char *fullpath);
+                       const char *fullpath,
+                       unsigned dirty_submodule1, unsigned dirty_submodule2);
  
- extern void diff_unmerge(struct diff_options *,
-                        const char *path,
-                        unsigned mode,
-                        const unsigned char *sha1);
+ extern struct diff_filepair *diff_unmerge(struct diff_options *, const char *path);
  
  #define DIFF_SETUP_REVERSE            1
  #define DIFF_SETUP_USE_CACHE          2
  #define DIFF_SETUP_USE_SIZE_CACHE     4
  
+ /*
+  * Poor man's alternative to parse-option, to allow both sticked form
+  * (--option=value) and separate form (--option value).
+  */
+ extern int parse_long_opt(const char *opt, const char **argv,
+                        const char **optarg);
  extern int git_diff_basic_config(const char *var, const char *value, void *cb);
  extern int git_diff_ui_config(const char *var, const char *value, void *cb);
  extern int diff_use_color_default;
@@@ -206,7 -234,11 +236,11 @@@ extern int diff_setup_done(struct diff_
  #define DIFF_PICKAXE_ALL      1
  #define DIFF_PICKAXE_REGEX    2
  
+ #define DIFF_PICKAXE_KIND_S   4 /* traditional plumbing counter */
+ #define DIFF_PICKAXE_KIND_G   8 /* grep in the patch */
  extern void diffcore_std(struct diff_options *);
+ extern void diffcore_fix_diff_index(struct diff_options *);
  
  #define COMMON_DIFF_OPTIONS_HELP \
  "\ncommon diff options:\n" \
@@@ -273,4 -305,12 +307,12 @@@ extern void diff_no_index(struct rev_in
  
  extern int index_differs_from(const char *def, int diff_flags);
  
+ extern size_t fill_textconv(struct userdiff_driver *driver,
+                           struct diff_filespec *df,
+                           char **outbuf);
+ extern struct userdiff_driver *get_textconv(struct diff_filespec *one);
+ extern int parse_rename_score(const char **cp_p);
  #endif /* DIFF_H */
index 3c728a3ebf9ce52e5c24c81525d5cb749cfb2957,abc49348b196cf0fec232b6f2399356e4fe324d5..3c728a3ebf9ce52e5c24c81525d5cb749cfb2957
@@@ -67,9 -67,4 +67,9 @@@ test_expect_success 'diff-files --diff-
        test_must_fail git diff-files --diff-filter=M --quiet
  '
  
 +test_expect_success 'diff-tree --diff-filter --quiet' '
 +      git commit -a -m "worktree state" &&
 +      test_must_fail git diff-tree --diff-filter=M --quiet HEAD^ HEAD
 +'
 +
  test_done
diff --combined tree-diff.c
index 33881d1ad0b7381db4bd39c97e160d93f62a1cdb,76f83fcc27e50b12ddbc8f72badd8d29f5b4230d..072c441601d2268c3036518d7704b1122271600e
@@@ -6,34 -6,17 +6,17 @@@
  #include "diffcore.h"
  #include "tree.h"
  
- static char *malloc_base(const char *base, int baselen, const char *path, int pathlen)
- {
-       char *newbase = xmalloc(baselen + pathlen + 2);
-       memcpy(newbase, base, baselen);
-       memcpy(newbase + baselen, path, pathlen);
-       memcpy(newbase + baselen + pathlen, "/", 2);
-       return newbase;
- }
- static char *malloc_fullname(const char *base, int baselen, const char *path, int pathlen)
- {
-       char *fullname = xmalloc(baselen + pathlen + 1);
-       memcpy(fullname, base, baselen);
-       memcpy(fullname + baselen, path, pathlen);
-       fullname[baselen + pathlen] = 0;
-       return fullname;
- }
+ static void show_entry(struct diff_options *opt, const char *prefix,
+                      struct tree_desc *desc, struct strbuf *base);
  
- static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
-                      const char *base, int baselen);
- static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
+ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2,
+                             struct strbuf *base, struct diff_options *opt)
  {
        unsigned mode1, mode2;
        const char *path1, *path2;
        const unsigned char *sha1, *sha2;
        int cmp, pathlen1, pathlen2;
-       char *fullname;
+       int old_baselen = base->len;
  
        sha1 = tree_entry_extract(t1, &path1, &mode1);
        sha2 = tree_entry_extract(t2, &path2, &mode2);
        pathlen2 = tree_entry_len(path2, sha2);
        cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
        if (cmp < 0) {
-               show_entry(opt, "-", t1, base, baselen);
+               show_entry(opt, "-", t1, base);
                return -1;
        }
        if (cmp > 0) {
-               show_entry(opt, "+", t2, base, baselen);
+               show_entry(opt, "+", t2, base);
                return 1;
        }
        if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
         * file, we need to consider it a remove and an add.
         */
        if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
-               show_entry(opt, "-", t1, base, baselen);
-               show_entry(opt, "+", t2, base, baselen);
+               show_entry(opt, "-", t1, base);
+               show_entry(opt, "+", t2, base);
                return 0;
        }
  
+       strbuf_add(base, path1, pathlen1);
        if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
-               int retval;
-               char *newbase = malloc_base(base, baselen, path1, pathlen1);
                if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
-                       newbase[baselen + pathlen1] = 0;
                        opt->change(opt, mode1, mode2,
-                                   sha1, sha2, newbase);
-                       newbase[baselen + pathlen1] = '/';
+                                   sha1, sha2, base->buf, 0, 0);
                }
-               retval = diff_tree_sha1(sha1, sha2, newbase, opt);
-               free(newbase);
-               return retval;
+               strbuf_addch(base, '/');
+               diff_tree_sha1(sha1, sha2, base->buf, opt);
+       } else {
+               opt->change(opt, mode1, mode2, sha1, sha2, base->buf, 0, 0);
        }
-       fullname = malloc_fullname(base, baselen, path1, pathlen1);
-       opt->change(opt, mode1, mode2, sha1, sha2, fullname);
-       free(fullname);
+       strbuf_setlen(base, old_baselen);
        return 0;
  }
  
- /*
-  * Is a tree entry interesting given the pathspec we have?
-  *
-  * Return:
-  *  - 2 for "yes, and all subsequent entries will be"
-  *  - 1 for yes
-  *  - zero for no
-  *  - negative for "no, and no subsequent entries will be either"
-  */
- static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
- {
-       const char *path;
-       const unsigned char *sha1;
-       unsigned mode;
-       int i;
-       int pathlen;
-       int never_interesting = -1;
-       if (!opt->nr_paths)
-               return 1;
-       sha1 = tree_entry_extract(desc, &path, &mode);
-       pathlen = tree_entry_len(path, sha1);
-       for (i = 0; i < opt->nr_paths; i++) {
-               const char *match = opt->paths[i];
-               int matchlen = opt->pathlens[i];
-               int m = -1; /* signals that we haven't called strncmp() */
-               if (baselen >= matchlen) {
-                       /* If it doesn't match, move along... */
-                       if (strncmp(base, match, matchlen))
-                               continue;
-                       /*
-                        * If the base is a subdirectory of a path which
-                        * was specified, all of them are interesting.
-                        */
-                       if (!matchlen ||
-                           base[matchlen] == '/' ||
-                           match[matchlen - 1] == '/')
-                               return 2;
-                       /* Just a random prefix match */
-                       continue;
-               }
-               /* Does the base match? */
-               if (strncmp(base, match, baselen))
-                       continue;
-               match += baselen;
-               matchlen -= baselen;
-               if (never_interesting) {
-                       /*
-                        * We have not seen any match that sorts later
-                        * than the current path.
-                        */
-                       /*
-                        * Does match sort strictly earlier than path
-                        * with their common parts?
-                        */
-                       m = strncmp(match, path,
-                                   (matchlen < pathlen) ? matchlen : pathlen);
-                       if (m < 0)
-                               continue;
-                       /*
-                        * If we come here even once, that means there is at
-                        * least one pathspec that would sort equal to or
-                        * later than the path we are currently looking at.
-                        * In other words, if we have never reached this point
-                        * after iterating all pathspecs, it means all
-                        * pathspecs are either outside of base, or inside the
-                        * base but sorts strictly earlier than the current
-                        * one.  In either case, they will never match the
-                        * subsequent entries.  In such a case, we initialized
-                        * the variable to -1 and that is what will be
-                        * returned, allowing the caller to terminate early.
-                        */
-                       never_interesting = 0;
-               }
-               if (pathlen > matchlen)
-                       continue;
-               if (matchlen > pathlen) {
-                       if (match[pathlen] != '/')
-                               continue;
-                       if (!S_ISDIR(mode))
-                               continue;
-               }
-               if (m == -1)
-                       /*
-                        * we cheated and did not do strncmp(), so we do
-                        * that here.
-                        */
-                       m = strncmp(match, path, pathlen);
-               /*
-                * If common part matched earlier then it is a hit,
-                * because we rejected the case where path is not a
-                * leading directory and is shorter than match.
-                */
-               if (!m)
-                       return 1;
-       }
-       return never_interesting; /* No matches */
- }
  /* A whole sub-tree went away or appeared */
- static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
+ static void show_tree(struct diff_options *opt, const char *prefix,
+                     struct tree_desc *desc, struct strbuf *base)
  {
        int all_interesting = 0;
        while (desc->size) {
                if (all_interesting)
                        show = 1;
                else {
-                       show = tree_entry_interesting(desc, base, baselen,
-                                                     opt);
+                       show = tree_entry_interesting(&desc->entry, base, 0,
+                                                     &opt->pathspec);
                        if (show == 2)
                                all_interesting = 1;
                }
                if (show < 0)
                        break;
                if (show)
-                       show_entry(opt, prefix, desc, base, baselen);
+                       show_entry(opt, prefix, desc, base);
                update_tree_entry(desc);
        }
  }
  
  /* A file entry went away or appeared */
- static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
-                      const char *base, int baselen)
+ static void show_entry(struct diff_options *opt, const char *prefix,
+                      struct tree_desc *desc, struct strbuf *base)
  {
        unsigned mode;
        const char *path;
        const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
        int pathlen = tree_entry_len(path, sha1);
+       int old_baselen = base->len;
  
+       strbuf_add(base, path, pathlen);
        if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
                enum object_type type;
-               char *newbase = malloc_base(base, baselen, path, pathlen);
                struct tree_desc inner;
                void *tree;
                unsigned long size;
                if (!tree || type != OBJ_TREE)
                        die("corrupt tree sha %s", sha1_to_hex(sha1));
  
-               if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
-                       newbase[baselen + pathlen] = 0;
-                       opt->add_remove(opt, *prefix, mode, sha1, newbase);
-                       newbase[baselen + pathlen] = '/';
-               }
+               if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE))
+                       opt->add_remove(opt, *prefix, mode, sha1, base->buf, 0);
  
-               init_tree_desc(&inner, tree, size);
-               show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
+               strbuf_addch(base, '/');
  
+               init_tree_desc(&inner, tree, size);
+               show_tree(opt, prefix, &inner, base);
                free(tree);
-               free(newbase);
-       } else {
-               char *fullname = malloc_fullname(base, baselen, path, pathlen);
-               opt->add_remove(opt, prefix[0], mode, sha1, fullname);
-               free(fullname);
-       }
+       } else
+               opt->add_remove(opt, prefix[0], mode, sha1, base->buf, 0);
+       strbuf_setlen(base, old_baselen);
  }
  
- static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
+ static void skip_uninteresting(struct tree_desc *t, struct strbuf *base,
+                              struct diff_options *opt, int *all_interesting)
  {
-       int all_interesting = 0;
        while (t->size) {
-               int show;
-               if (all_interesting)
-                       show = 1;
-               else {
-                       show = tree_entry_interesting(t, base, baselen, opt);
-                       if (show == 2)
-                               all_interesting = 1;
-               }
+               int show = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec);
+               if (show == 2)
+                       *all_interesting = 1;
                if (!show) {
                        update_tree_entry(t);
                        continue;
        }
  }
  
- int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
+ int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
+             const char *base_str, struct diff_options *opt)
  {
-       int baselen = strlen(base);
+       struct strbuf base;
+       int baselen = strlen(base_str);
+       int all_t1_interesting = 0;
+       int all_t2_interesting = 0;
+       /* Enable recursion indefinitely */
+       opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE);
+       opt->pathspec.max_depth = -1;
+       strbuf_init(&base, PATH_MAX);
+       strbuf_add(&base, base_str, baselen);
  
        for (;;) {
 -              if (DIFF_OPT_TST(opt, QUICK) &&
 -                  DIFF_OPT_TST(opt, HAS_CHANGES))
 +              if (diff_can_quit_early(opt))
                        break;
-               if (opt->nr_paths) {
-                       skip_uninteresting(t1, base, baselen, opt);
-                       skip_uninteresting(t2, base, baselen, opt);
+               if (opt->pathspec.nr) {
+                       if (!all_t1_interesting)
+                               skip_uninteresting(t1, &base, opt, &all_t1_interesting);
+                       if (!all_t2_interesting)
+                               skip_uninteresting(t2, &base, opt, &all_t2_interesting);
                }
                if (!t1->size) {
                        if (!t2->size)
                                break;
-                       show_entry(opt, "+", t2, base, baselen);
+                       show_entry(opt, "+", t2, &base);
                        update_tree_entry(t2);
                        continue;
                }
                if (!t2->size) {
-                       show_entry(opt, "-", t1, base, baselen);
+                       show_entry(opt, "-", t1, &base);
                        update_tree_entry(t1);
                        continue;
                }
-               switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
+               switch (compare_tree_entry(t1, t2, &base, opt)) {
                case -1:
                        update_tree_entry(t1);
                        continue;
                }
                die("git diff-tree: internal error");
        }
+       strbuf_release(&base);
        return 0;
  }
  
@@@ -345,9 -217,9 +216,9 @@@ static void try_to_follow_renames(struc
  
        diff_setup(&diff_opts);
        DIFF_OPT_SET(&diff_opts, RECURSIVE);
-       diff_opts.detect_rename = DIFF_DETECT_RENAME;
+       DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
        diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-       diff_opts.single_follow = opt->paths[0];
+       diff_opts.single_follow = opt->pathspec.raw[0];
        diff_opts.break_opt = opt->break_opt;
        paths[0] = NULL;
        diff_tree_setup_paths(paths, &diff_opts);
        diff_tree_release_paths(&diff_opts);
  
        /* Go through the new set of filepairing, and see if we find a more interesting one */
+       opt->found_follow = 0;
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
  
                 * diff_queued_diff, we will also use that as the path in
                 * the future!
                 */
-               if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) {
+               if ((p->status == 'R' || p->status == 'C') &&
+                   !strcmp(p->two->path, opt->pathspec.raw[0])) {
                        /* Switch the file-pairs around */
                        q->queue[i] = choice;
                        choice = p;
  
                        /* Update the path we use from now on.. */
                        diff_tree_release_paths(opt);
-                       opt->paths[0] = xstrdup(p->one->path);
-                       diff_tree_setup_paths(opt->paths, opt);
+                       opt->pathspec.raw[0] = xstrdup(p->one->path);
+                       diff_tree_setup_paths(opt->pathspec.raw, opt);
+                       /*
+                        * The caller expects us to return a set of vanilla
+                        * filepairs to let a later call to diffcore_std()
+                        * it makes to sort the renames out (among other
+                        * things), but we already have found renames
+                        * ourselves; signal diffcore_std() not to muck with
+                        * rename information.
+                        */
+                       opt->found_follow = 1;
                        break;
                }
        }
@@@ -411,7 -295,7 +294,7 @@@ int diff_tree_sha1(const unsigned char 
        init_tree_desc(&t1, tree1, size1);
        init_tree_desc(&t2, tree2, size2);
        retval = diff_tree(&t1, &t2, base, opt);
-       if (DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
+       if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
                init_tree_desc(&t1, tree1, size1);
                init_tree_desc(&t2, tree2, size2);
                try_to_follow_renames(&t1, &t2, base, opt);
@@@ -439,36 -323,12 +322,12 @@@ int diff_root_tree_sha1(const unsigned 
        return retval;
  }
  
- static int count_paths(const char **paths)
- {
-       int i = 0;
-       while (*paths++)
-               i++;
-       return i;
- }
  void diff_tree_release_paths(struct diff_options *opt)
  {
-       free(opt->pathlens);
+       free_pathspec(&opt->pathspec);
  }
  
  void diff_tree_setup_paths(const char **p, struct diff_options *opt)
  {
-       opt->nr_paths = 0;
-       opt->pathlens = NULL;
-       opt->paths = NULL;
-       if (p) {
-               int i;
-               opt->paths = p;
-               opt->nr_paths = count_paths(p);
-               if (opt->nr_paths == 0) {
-                       opt->pathlens = NULL;
-                       return;
-               }
-               opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
-               for (i=0; i < opt->nr_paths; i++)
-                       opt->pathlens[i] = strlen(p[i]);
-       }
+       init_pathspec(&opt->pathspec, p);
  }