builtin/difftool.c

   1 /*
   2  * "git difftool" builtin command
   3  *
   4  * This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
   5  * git-difftool--helper script.
   6  *
   7  * This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
   8  * The GIT_DIFF* variables are exported for use by git-difftool--helper.
   9  *
  10  * Any arguments that are unknown to this script are forwarded to 'git diff'.
  11  *
  12  * Copyright (C) 2016 Johannes Schindelin
  13  */
  14
  15 #include "builtin.h"
  16
  17 #include "abspath.h"
  18 #include "config.h"
  19 #include "copy.h"
  20 #include "run-command.h"
  21 #include "environment.h"
  22 #include "gettext.h"
  23 #include "hex.h"
  24 #include "parse-options.h"
  25 #include "path.h"
  26 #include "read-cache-ll.h"
  27 #include "repository.h"
  28 #include "sparse-index.h"
  29 #include "strvec.h"
  30 #include "strbuf.h"
  31 #include "lockfile.h"
  32 #include "object-file.h"
  33 #include "object-store.h"
  34 #include "dir.h"
  35 #include "entry.h"
  36 #include "setup.h"
  37
  38 static const char *const builtin_difftool_usage[] = {
  39         N_("git difftool [<options>] [<commit> [<commit>]] [--] [<path>...]"),
  40         NULL
  41 };
  42
  43 struct difftool_options {
  44         int has_symlinks;
  45         int symlinks;
  46         int trust_exit_code;
  47 };
  48
  49 static int difftool_config(const char *var, const char *value,
  50                            const struct config_context *ctx, void *cb)
  51 {
  52         struct difftool_options *dt_options = (struct difftool_options *)cb;
  53         if (!strcmp(var, "difftool.trustexitcode")) {
  54                 dt_options->trust_exit_code = git_config_bool(var, value);
  55                 return 0;
  56         }
  57         if (!strcmp(var, "core.symlinks")) {
  58                 dt_options->has_symlinks = git_config_bool(var, value);
  59                 return 0;
  60         }
  61
  62         return git_default_config(var, value, ctx, cb);
  63 }
  64
  65 static int print_tool_help(void)
  66 {
  67         struct child_process cmd = CHILD_PROCESS_INIT;
  68
  69         cmd.git_cmd = 1;
  70         strvec_pushl(&cmd.args, "mergetool", "--tool-help=diff", NULL);
  71         return run_command(&cmd);
  72 }
  73
  74 static int parse_index_info(struct repository *repo,
  75                             char *p, int *mode1, int *mode2,
  76                             struct object_id *oid1, struct object_id *oid2,
  77                             char *status)
  78 {
  79         if (*p != ':')
  80                 return error("expected ':', got '%c'", *p);
  81         *mode1 = (int)strtol(p + 1, &p, 8);
  82         if (*p != ' ')
  83                 return error("expected ' ', got '%c'", *p);
  84         *mode2 = (int)strtol(p + 1, &p, 8);
  85         if (*p != ' ')
  86                 return error("expected ' ', got '%c'", *p);
  87         if (parse_oid_hex_algop(++p, oid1, (const char **)&p, repo->hash_algo))
  88                 return error("expected object ID, got '%s'", p);
  89         if (*p != ' ')
  90                 return error("expected ' ', got '%c'", *p);
  91         if (parse_oid_hex_algop(++p, oid2, (const char **)&p, repo->hash_algo))
  92                 return error("expected object ID, got '%s'", p);
  93         if (*p != ' ')
  94                 return error("expected ' ', got '%c'", *p);
  95         *status = *++p;
  96         if (!*status)
  97                 return error("missing status");
  98         if (p[1] && !isdigit(p[1]))
  99                 return error("unexpected trailer: '%s'", p + 1);
 100         return 0;
 101 }
 102
 103 /*
 104  * Remove any trailing slash from $workdir
 105  * before starting to avoid double slashes in symlink targets.
 106  */
 107 static void add_path(struct strbuf *buf, size_t base_len, const char *path)
 108 {
 109         strbuf_setlen(buf, base_len);
 110         if (buf->len && buf->buf[buf->len - 1] != '/')
 111                 strbuf_addch(buf, '/');
 112         strbuf_addstr(buf, path);
 113 }
 114
 115 /*
 116  * Determine whether we can simply reuse the file in the worktree.
 117  */
 118 static int use_wt_file(struct repository *repo,
 119                        const char *workdir, const char *name,
 120                        struct object_id *oid)
 121 {
 122         struct strbuf buf = STRBUF_INIT;
 123         struct stat st;
 124         int use = 0;
 125
 126         strbuf_addstr(&buf, workdir);
 127         add_path(&buf, buf.len, name);
 128
 129         if (!lstat(buf.buf, &st) && !S_ISLNK(st.st_mode)) {
 130                 struct object_id wt_oid;
 131                 int fd = open(buf.buf, O_RDONLY);
 132
 133                 if (fd >= 0 &&
 134                     !index_fd(repo->index, &wt_oid, fd, &st, OBJ_BLOB, name, 0)) {
 135                         if (is_null_oid(oid)) {
 136                                 oidcpy(oid, &wt_oid);
 137                                 use = 1;
 138                         } else if (oideq(oid, &wt_oid))
 139                                 use = 1;
 140                 }
 141         }
 142
 143         strbuf_release(&buf);
 144
 145         return use;
 146 }
 147
 148 struct working_tree_entry {
 149         struct hashmap_entry entry;
 150         char path[FLEX_ARRAY];
 151 };
 152
 153 static int working_tree_entry_cmp(const void *cmp_data UNUSED,
 154                                   const struct hashmap_entry *eptr,
 155                                   const struct hashmap_entry *entry_or_key,
 156                                   const void *keydata UNUSED)
 157 {
 158         const struct working_tree_entry *a, *b;
 159
 160         a = container_of(eptr, const struct working_tree_entry, entry);
 161         b = container_of(entry_or_key, const struct working_tree_entry, entry);
 162
 163         return strcmp(a->path, b->path);
 164 }
 165
 166 /*
 167  * The `left` and `right` entries hold paths for the symlinks hashmap,
 168  * and a SHA-1 surrounded by brief text for submodules.
 169  */
 170 struct pair_entry {
 171         struct hashmap_entry entry;
 172         char left[PATH_MAX], right[PATH_MAX];
 173         const char path[FLEX_ARRAY];
 174 };
 175
 176 static int pair_cmp(const void *cmp_data UNUSED,
 177                     const struct hashmap_entry *eptr,
 178                     const struct hashmap_entry *entry_or_key,
 179                     const void *keydata UNUSED)
 180 {
 181         const struct pair_entry *a, *b;
 182
 183         a = container_of(eptr, const struct pair_entry, entry);
 184         b = container_of(entry_or_key, const struct pair_entry, entry);
 185
 186         return strcmp(a->path, b->path);
 187 }
 188
 189 static void add_left_or_right(struct hashmap *map, const char *path,
 190                               const char *content, int is_right)
 191 {
 192         struct pair_entry *e, *existing;
 193
 194         FLEX_ALLOC_STR(e, path, path);
 195         hashmap_entry_init(&e->entry, strhash(path));
 196         existing = hashmap_get_entry(map, e, entry, NULL);
 197         if (existing) {
 198                 free(e);
 199                 e = existing;
 200         } else {
 201                 e->left[0] = e->right[0] = '\0';
 202                 hashmap_add(map, &e->entry);
 203         }
 204         strlcpy(is_right ? e->right : e->left, content, PATH_MAX);
 205 }
 206
 207 struct path_entry {
 208         struct hashmap_entry entry;
 209         char path[FLEX_ARRAY];
 210 };
 211
 212 static int path_entry_cmp(const void *cmp_data UNUSED,
 213                           const struct hashmap_entry *eptr,
 214                           const struct hashmap_entry *entry_or_key,
 215                           const void *key)
 216 {
 217         const struct path_entry *a, *b;
 218
 219         a = container_of(eptr, const struct path_entry, entry);
 220         b = container_of(entry_or_key, const struct path_entry, entry);
 221
 222         return strcmp(a->path, key ? key : b->path);
 223 }
 224
 225 static void changed_files(struct repository *repo,
 226                           struct hashmap *result, const char *index_path,
 227                           const char *workdir)
 228 {
 229         struct child_process update_index = CHILD_PROCESS_INIT;
 230         struct child_process diff_files = CHILD_PROCESS_INIT;
 231         struct strbuf buf = STRBUF_INIT;
 232         const char *git_dir = absolute_path(repo_get_git_dir(repo));
 233         FILE *fp;
 234
 235         strvec_pushl(&update_index.args,
 236                      "--git-dir", git_dir, "--work-tree", workdir,
 237                      "update-index", "--really-refresh", "-q",
 238                      "--unmerged", NULL);
 239         update_index.no_stdin = 1;
 240         update_index.no_stdout = 1;
 241         update_index.no_stderr = 1;
 242         update_index.git_cmd = 1;
 243         update_index.use_shell = 0;
 244         update_index.clean_on_exit = 1;
 245         update_index.dir = workdir;
 246         strvec_pushf(&update_index.env, "GIT_INDEX_FILE=%s", index_path);
 247         /* Ignore any errors of update-index */
 248         run_command(&update_index);
 249
 250         strvec_pushl(&diff_files.args,
 251                      "--git-dir", git_dir, "--work-tree", workdir,
 252                      "diff-files", "--name-only", "-z", NULL);
 253         diff_files.no_stdin = 1;
 254         diff_files.git_cmd = 1;
 255         diff_files.use_shell = 0;
 256         diff_files.clean_on_exit = 1;
 257         diff_files.out = -1;
 258         diff_files.dir = workdir;
 259         strvec_pushf(&diff_files.env, "GIT_INDEX_FILE=%s", index_path);
 260         if (start_command(&diff_files))
 261                 die("could not obtain raw diff");
 262         fp = xfdopen(diff_files.out, "r");
 263         while (!strbuf_getline_nul(&buf, fp)) {
 264                 struct path_entry *entry;
 265                 FLEX_ALLOC_STR(entry, path, buf.buf);
 266                 hashmap_entry_init(&entry->entry, strhash(buf.buf));
 267                 hashmap_add(result, &entry->entry);
 268         }
 269         fclose(fp);
 270         if (finish_command(&diff_files))
 271                 die("diff-files did not exit properly");
 272         strbuf_release(&buf);
 273 }
 274
 275 static int ensure_leading_directories(struct repository *repo, char *path)
 276 {
 277         switch (safe_create_leading_directories(repo, path)) {
 278                 case SCLD_OK:
 279                 case SCLD_EXISTS:
 280                         return 0;
 281                 default:
 282                         return error(_("could not create leading directories "
 283                                        "of '%s'"), path);
 284         }
 285 }
 286
 287 /*
 288  * Unconditional writing of a plain regular file is what
 289  * "git difftool --dir-diff" wants to do for symlinks.  We are preparing two
 290  * temporary directories to be fed to a Git-unaware tool that knows how to
 291  * show a diff of two directories (e.g. "diff -r A B").
 292  *
 293  * Because the tool is Git-unaware, if a symbolic link appears in either of
 294  * these temporary directories, it will try to dereference and show the
 295  * difference of the target of the symbolic link, which is not what we want,
 296  * as the goal of the dir-diff mode is to produce an output that is logically
 297  * equivalent to what "git diff" produces.
 298  *
 299  * Most importantly, we want to get textual comparison of the result of the
 300  * readlink(2).  get_symlink() provides that---it returns the contents of
 301  * the symlink that gets written to a regular file to force the external tool
 302  * to compare the readlink(2) result as text, even on a filesystem that is
 303  * capable of doing a symbolic link.
 304  */
 305 static char *get_symlink(struct repository *repo,
 306                          struct difftool_options *dt_options,
 307                          const struct object_id *oid, const char *path)
 308 {
 309         char *data;
 310         if (is_null_oid(oid)) {
 311                 /* The symlink is unknown to Git so read from the filesystem */
 312                 struct strbuf link = STRBUF_INIT;
 313                 if (dt_options->has_symlinks) {
 314                         if (strbuf_readlink(&link, path, strlen(path)))
 315                                 die(_("could not read symlink %s"), path);
 316                 } else if (strbuf_read_file(&link, path, 128))
 317                         die(_("could not read symlink file %s"), path);
 318
 319                 data = strbuf_detach(&link, NULL);
 320         } else {
 321                 enum object_type type;
 322                 unsigned long size;
 323                 data = repo_read_object_file(repo, oid, &type, &size);
 324                 if (!data)
 325                         die(_("could not read object %s for symlink %s"),
 326                                 oid_to_hex(oid), path);
 327         }
 328
 329         return data;
 330 }
 331
 332 static int checkout_path(unsigned mode, struct object_id *oid,
 333                          const char *path, const struct checkout *state)
 334 {
 335         struct cache_entry *ce;
 336         int ret;
 337
 338         ce = make_transient_cache_entry(mode, oid, path, 0, NULL);
 339         ret = checkout_entry(ce, state, NULL, NULL);
 340
 341         discard_cache_entry(ce);
 342         return ret;
 343 }
 344
 345 static void write_file_in_directory(struct repository *repo,
 346                                     struct strbuf *dir, size_t dir_len,
 347                                     const char *path, const char *content)
 348 {
 349         add_path(dir, dir_len, path);
 350         ensure_leading_directories(repo, dir->buf);
 351         unlink(dir->buf);
 352         write_file(dir->buf, "%s", content);
 353 }
 354
 355 /* Write the file contents for the left and right sides of the difftool
 356  * dir-diff representation for submodules and symlinks. Symlinks and submodules
 357  * are written as regular text files so that external diff tools can diff them
 358  * as text files, resulting in behavior that is analogous to what "git diff"
 359  * displays for symlink and submodule diffs.
 360  */
 361 static void write_standin_files(struct repository *repo,
 362                                 struct pair_entry *entry,
 363                                 struct strbuf *ldir, size_t ldir_len,
 364                                 struct strbuf *rdir, size_t rdir_len)
 365 {
 366         if (*entry->left)
 367                 write_file_in_directory(repo, ldir, ldir_len, entry->path, entry->left);
 368         if (*entry->right)
 369                 write_file_in_directory(repo, rdir, rdir_len, entry->path, entry->right);
 370 }
 371
 372 static int run_dir_diff(struct repository *repo,
 373                         struct difftool_options *dt_options,
 374                         const char *extcmd, const char *prefix,
 375                         struct child_process *child)
 376 {
 377         struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
 378         struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
 379         struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
 380         struct strbuf wtdir = STRBUF_INIT;
 381         struct strbuf tmpdir = STRBUF_INIT;
 382         char *lbase_dir = NULL, *rbase_dir = NULL;
 383         size_t ldir_len, rdir_len, wtdir_len;
 384         const char *workdir, *tmp;
 385         int ret = 0;
 386         size_t i;
 387         FILE *fp = NULL;
 388         struct hashmap working_tree_dups = HASHMAP_INIT(working_tree_entry_cmp,
 389                                                         NULL);
 390         struct hashmap submodules = HASHMAP_INIT(pair_cmp, NULL);
 391         struct hashmap symlinks2 = HASHMAP_INIT(pair_cmp, NULL);
 392         struct hashmap_iter iter;
 393         struct pair_entry *entry;
 394         struct index_state wtindex = INDEX_STATE_INIT(repo);
 395         struct checkout lstate, rstate;
 396         int err = 0;
 397         struct child_process cmd = CHILD_PROCESS_INIT;
 398         struct hashmap wt_modified = HASHMAP_INIT(path_entry_cmp, NULL);
 399         struct hashmap tmp_modified = HASHMAP_INIT(path_entry_cmp, NULL);
 400         int indices_loaded = 0;
 401
 402         workdir = repo_get_work_tree(repo);
 403
 404         /* Setup temp directories */
 405         tmp = getenv("TMPDIR");
 406         strbuf_add_absolute_path(&tmpdir, tmp ? tmp : "/tmp");
 407         strbuf_trim_trailing_dir_sep(&tmpdir);
 408         strbuf_addstr(&tmpdir, "/git-difftool.XXXXXX");
 409         if (!mkdtemp(tmpdir.buf)) {
 410                 ret = error("could not create '%s'", tmpdir.buf);
 411                 goto finish;
 412         }
 413         strbuf_addf(&ldir, "%s/left/", tmpdir.buf);
 414         strbuf_addf(&rdir, "%s/right/", tmpdir.buf);
 415         strbuf_addstr(&wtdir, workdir);
 416         if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
 417                 strbuf_addch(&wtdir, '/');
 418         mkdir(ldir.buf, 0700);
 419         mkdir(rdir.buf, 0700);
 420
 421         memset(&lstate, 0, sizeof(lstate));
 422         lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
 423         lstate.base_dir_len = ldir.len;
 424         lstate.force = 1;
 425         memset(&rstate, 0, sizeof(rstate));
 426         rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
 427         rstate.base_dir_len = rdir.len;
 428         rstate.force = 1;
 429
 430         ldir_len = ldir.len;
 431         rdir_len = rdir.len;
 432         wtdir_len = wtdir.len;
 433
 434         child->no_stdin = 1;
 435         child->git_cmd = 1;
 436         child->use_shell = 0;
 437         child->clean_on_exit = 1;
 438         child->dir = prefix;
 439         child->out = -1;
 440         if (start_command(child))
 441                 die("could not obtain raw diff");
 442         fp = xfdopen(child->out, "r");
 443
 444         /* Build index info for left and right sides of the diff */
 445         i = 0;
 446         while (!strbuf_getline_nul(&info, fp)) {
 447                 int lmode, rmode;
 448                 struct object_id loid, roid;
 449                 char status;
 450                 const char *src_path, *dst_path;
 451
 452                 if (starts_with(info.buf, "::"))
 453                         die(N_("combined diff formats ('-c' and '--cc') are "
 454                                "not supported in\n"
 455                                "directory diff mode ('-d' and '--dir-diff')."));
 456
 457                 if (parse_index_info(repo, info.buf, &lmode, &rmode, &loid, &roid, &status))
 458                         break;
 459                 if (strbuf_getline_nul(&lpath, fp))
 460                         break;
 461                 src_path = lpath.buf;
 462
 463                 i++;
 464                 if (status != 'C' && status != 'R') {
 465                         dst_path = src_path;
 466                 } else {
 467                         if (strbuf_getline_nul(&rpath, fp))
 468                                 break;
 469                         dst_path = rpath.buf;
 470                 }
 471
 472                 if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
 473                         strbuf_reset(&buf);
 474                         strbuf_addf(&buf, "Subproject commit %s",
 475                                     oid_to_hex(&loid));
 476                         add_left_or_right(&submodules, src_path, buf.buf, 0);
 477                         strbuf_reset(&buf);
 478                         strbuf_addf(&buf, "Subproject commit %s",
 479                                     oid_to_hex(&roid));
 480                         if (oideq(&loid, &roid))
 481                                 strbuf_addstr(&buf, "-dirty");
 482                         add_left_or_right(&submodules, dst_path, buf.buf, 1);
 483                         continue;
 484                 }
 485
 486                 if (S_ISLNK(lmode)) {
 487                         char *content = get_symlink(repo, dt_options, &loid, src_path);
 488                         add_left_or_right(&symlinks2, src_path, content, 0);
 489                         free(content);
 490                 }
 491
 492                 if (S_ISLNK(rmode)) {
 493                         char *content = get_symlink(repo, dt_options, &roid, dst_path);
 494                         add_left_or_right(&symlinks2, dst_path, content, 1);
 495                         free(content);
 496                 }
 497
 498                 if (lmode && status != 'C') {
 499                         if (checkout_path(lmode, &loid, src_path, &lstate)) {
 500                                 ret = error("could not write '%s'", src_path);
 501                                 goto finish;
 502                         }
 503                 }
 504
 505                 if (rmode && !S_ISLNK(rmode)) {
 506                         struct working_tree_entry *entry;
 507
 508                         /* Avoid duplicate working_tree entries */
 509                         FLEX_ALLOC_STR(entry, path, dst_path);
 510                         hashmap_entry_init(&entry->entry, strhash(dst_path));
 511                         if (hashmap_get(&working_tree_dups, &entry->entry,
 512                                         NULL)) {
 513                                 free(entry);
 514                                 continue;
 515                         }
 516                         hashmap_add(&working_tree_dups, &entry->entry);
 517
 518                         if (!use_wt_file(repo, workdir, dst_path, &roid)) {
 519                                 if (checkout_path(rmode, &roid, dst_path,
 520                                                   &rstate)) {
 521                                         ret = error("could not write '%s'",
 522                                                     dst_path);
 523                                         goto finish;
 524                                 }
 525                         } else if (!is_null_oid(&roid)) {
 526                                 /*
 527                                  * Changes in the working tree need special
 528                                  * treatment since they are not part of the
 529                                  * index.
 530                                  */
 531                                 struct cache_entry *ce2 =
 532                                         make_cache_entry(&wtindex, rmode, &roid,
 533                                                          dst_path, 0, 0);
 534
 535                                 add_index_entry(&wtindex, ce2,
 536                                                 ADD_CACHE_JUST_APPEND);
 537
 538                                 add_path(&rdir, rdir_len, dst_path);
 539                                 if (ensure_leading_directories(repo, rdir.buf)) {
 540                                         ret = error("could not create "
 541                                                     "directory for '%s'",
 542                                                     dst_path);
 543                                         goto finish;
 544                                 }
 545                                 add_path(&wtdir, wtdir_len, dst_path);
 546                                 if (dt_options->symlinks) {
 547                                         if (symlink(wtdir.buf, rdir.buf)) {
 548                                                 ret = error_errno("could not symlink '%s' to '%s'", wtdir.buf, rdir.buf);
 549                                                 goto finish;
 550                                         }
 551                                 } else {
 552                                         struct stat st;
 553                                         if (stat(wtdir.buf, &st))
 554                                                 st.st_mode = 0644;
 555                                         if (copy_file(rdir.buf, wtdir.buf,
 556                                                       st.st_mode)) {
 557                                                 ret = error("could not copy '%s' to '%s'", wtdir.buf, rdir.buf);
 558                                                 goto finish;
 559                                         }
 560                                 }
 561                         }
 562                 }
 563         }
 564
 565         fclose(fp);
 566         fp = NULL;
 567         if (finish_command(child)) {
 568                 ret = error("error occurred running diff --raw");
 569                 goto finish;
 570         }
 571
 572         if (!i)
 573                 goto finish;
 574
 575         /*
 576          * Changes to submodules require special treatment.This loop writes a
 577          * temporary file to both the left and right directories to show the
 578          * change in the recorded SHA1 for the submodule.
 579          */
 580         hashmap_for_each_entry(&submodules, &iter, entry,
 581                                 entry /* member name */) {
 582                 write_standin_files(repo, entry, &ldir, ldir_len, &rdir, rdir_len);
 583         }
 584
 585         /*
 586          * Symbolic links require special treatment. The standard "git diff"
 587          * shows only the link itself, not the contents of the link target.
 588          * This loop replicates that behavior.
 589          */
 590         hashmap_for_each_entry(&symlinks2, &iter, entry,
 591                                 entry /* member name */) {
 592
 593                 write_standin_files(repo, entry, &ldir, ldir_len, &rdir, rdir_len);
 594         }
 595
 596         strbuf_setlen(&ldir, ldir_len);
 597         strbuf_setlen(&rdir, rdir_len);
 598
 599         if (extcmd) {
 600                 strvec_push(&cmd.args, extcmd);
 601         } else {
 602                 strvec_push(&cmd.args, "difftool--helper");
 603                 cmd.git_cmd = 1;
 604                 setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
 605         }
 606         strvec_pushl(&cmd.args, ldir.buf, rdir.buf, NULL);
 607         ret = run_command(&cmd);
 608
 609         /* TODO: audit for interaction with sparse-index. */
 610         ensure_full_index(&wtindex);
 611
 612         /*
 613          * If the diff includes working copy files and those
 614          * files were modified during the diff, then the changes
 615          * should be copied back to the working tree.
 616          * Do not copy back files when symlinks are used and the
 617          * external tool did not replace the original link with a file.
 618          *
 619          * These hashes are loaded lazily since they aren't needed
 620          * in the common case of --symlinks and the difftool updating
 621          * files through the symlink.
 622          */
 623         for (i = 0; i < wtindex.cache_nr; i++) {
 624                 struct hashmap_entry dummy;
 625                 const char *name = wtindex.cache[i]->name;
 626                 struct stat st;
 627
 628                 add_path(&rdir, rdir_len, name);
 629                 if (lstat(rdir.buf, &st))
 630                         continue;
 631
 632                 if ((dt_options->symlinks && S_ISLNK(st.st_mode)) || !S_ISREG(st.st_mode))
 633                         continue;
 634
 635                 if (!indices_loaded) {
 636                         struct lock_file lock = LOCK_INIT;
 637                         strbuf_reset(&buf);
 638                         strbuf_addf(&buf, "%s/wtindex", tmpdir.buf);
 639                         if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
 640                             write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
 641                                 ret = error("could not write %s", buf.buf);
 642                                 goto finish;
 643                         }
 644                         changed_files(repo, &wt_modified, buf.buf, workdir);
 645                         strbuf_setlen(&rdir, rdir_len);
 646                         changed_files(repo, &tmp_modified, buf.buf, rdir.buf);
 647                         add_path(&rdir, rdir_len, name);
 648                         indices_loaded = 1;
 649                 }
 650
 651                 hashmap_entry_init(&dummy, strhash(name));
 652                 if (hashmap_get(&tmp_modified, &dummy, name)) {
 653                         add_path(&wtdir, wtdir_len, name);
 654                         if (hashmap_get(&wt_modified, &dummy, name)) {
 655                                 warning(_("both files modified: '%s' and '%s'."),
 656                                         wtdir.buf, rdir.buf);
 657                                 warning(_("working tree file has been left."));
 658                                 warning("%s", "");
 659                                 err = 1;
 660                         } else if (unlink(wtdir.buf) ||
 661                                    copy_file(wtdir.buf, rdir.buf, st.st_mode))
 662                                 warning_errno(_("could not copy '%s' to '%s'"),
 663                                               rdir.buf, wtdir.buf);
 664                 }
 665         }
 666
 667         if (err) {
 668                 warning(_("temporary files exist in '%s'."), tmpdir.buf);
 669                 warning(_("you may want to cleanup or recover these."));
 670                 ret = 1;
 671         } else {
 672                 remove_dir_recursively(&tmpdir, 0);
 673                 if (ret)
 674                         warning(_("failed: %d"), ret);
 675         }
 676
 677 finish:
 678         if (fp)
 679                 fclose(fp);
 680
 681         hashmap_clear_and_free(&working_tree_dups, struct working_tree_entry, entry);
 682         hashmap_clear_and_free(&wt_modified, struct path_entry, entry);
 683         hashmap_clear_and_free(&tmp_modified, struct path_entry, entry);
 684         hashmap_clear_and_free(&submodules, struct pair_entry, entry);
 685         hashmap_clear_and_free(&symlinks2, struct pair_entry, entry);
 686         release_index(&wtindex);
 687         free(lbase_dir);
 688         free(rbase_dir);
 689         strbuf_release(&info);
 690         strbuf_release(&lpath);
 691         strbuf_release(&rpath);
 692         strbuf_release(&ldir);
 693         strbuf_release(&rdir);
 694         strbuf_release(&wtdir);
 695         strbuf_release(&buf);
 696         strbuf_release(&tmpdir);
 697
 698         return (ret < 0) ? 1 : ret;
 699 }
 700
 701 static int run_file_diff(int prompt, const char *prefix,
 702                          struct child_process *child)
 703 {
 704         strvec_push(&child->env, "GIT_PAGER=");
 705         strvec_push(&child->env, "GIT_EXTERNAL_DIFF=git-difftool--helper");
 706         if (prompt > 0)
 707                 strvec_push(&child->env, "GIT_DIFFTOOL_PROMPT=true");
 708         else if (!prompt)
 709                 strvec_push(&child->env, "GIT_DIFFTOOL_NO_PROMPT=true");
 710
 711         child->git_cmd = 1;
 712         child->dir = prefix;
 713
 714         return run_command(child);
 715 }
 716
 717 int cmd_difftool(int argc,
 718                  const char **argv,
 719                  const char *prefix,
 720                  struct repository *repo)
 721 {
 722         int use_gui_tool = -1, dir_diff = 0, prompt = -1, tool_help = 0, no_index = 0;
 723         static char *difftool_cmd = NULL, *extcmd = NULL;
 724         struct difftool_options dt_options = {
 725                 .has_symlinks = 1,
 726                 .symlinks = 1,
 727                 .trust_exit_code = 0
 728         };
 729         struct option builtin_difftool_options[] = {
 730                 OPT_BOOL('g', "gui", &use_gui_tool,
 731                          N_("use `diff.guitool` instead of `diff.tool`")),
 732                 OPT_BOOL('d', "dir-diff", &dir_diff,
 733                          N_("perform a full-directory diff")),
 734                 OPT_SET_INT_F('y', "no-prompt", &prompt,
 735                         N_("do not prompt before launching a diff tool"),
 736                         0, PARSE_OPT_NONEG),
 737                 OPT_SET_INT_F(0, "prompt", &prompt, NULL,
 738                         1, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
 739                 OPT_BOOL(0, "symlinks", &dt_options.symlinks,
 740                          N_("use symlinks in dir-diff mode")),
 741                 OPT_STRING('t', "tool", &difftool_cmd, N_("tool"),
 742                            N_("use the specified diff tool")),
 743                 OPT_BOOL(0, "tool-help", &tool_help,
 744                          N_("print a list of diff tools that may be used with "
 745                             "`--tool`")),
 746                 OPT_BOOL(0, "trust-exit-code", &dt_options.trust_exit_code,
 747                          N_("make 'git-difftool' exit when an invoked diff "
 748                             "tool returns a non-zero exit code")),
 749                 OPT_STRING('x', "extcmd", &extcmd, N_("command"),
 750                            N_("specify a custom command for viewing diffs")),
 751                 OPT_BOOL(0, "no-index", &no_index, N_("passed to `diff`")),
 752                 OPT_END()
 753         };
 754         struct child_process child = CHILD_PROCESS_INIT;
 755
 756         repo_config(repo, difftool_config, &dt_options);
 757         dt_options.symlinks = dt_options.has_symlinks;
 758
 759         argc = parse_options(argc, argv, prefix, builtin_difftool_options,
 760                              builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN_OPT |
 761                              PARSE_OPT_KEEP_DASHDASH);
 762
 763         if (tool_help)
 764                 return print_tool_help();
 765
 766         if (!no_index && !startup_info->have_repository)
 767                 die(_("difftool requires worktree or --no-index"));
 768
 769         if (!no_index){
 770                 setup_work_tree();
 771                 setenv(GIT_DIR_ENVIRONMENT, absolute_path(repo_get_git_dir(repo)), 1);
 772                 setenv(GIT_WORK_TREE_ENVIRONMENT, absolute_path(repo_get_work_tree(repo)), 1);
 773         } else if (dir_diff)
 774                 die(_("options '%s' and '%s' cannot be used together"), "--dir-diff", "--no-index");
 775
 776         die_for_incompatible_opt3(use_gui_tool == 1, "--gui",
 777                                   !!difftool_cmd, "--tool",
 778                                   !!extcmd, "--extcmd");
 779
 780         /*
 781          * Explicitly specified GUI option is forwarded to git-mergetool--lib.sh;
 782          * empty or unset means "use the difftool.guiDefault config or default to
 783          * false".
 784          */
 785         if (use_gui_tool == 1)
 786                 setenv("GIT_MERGETOOL_GUI", "true", 1);
 787         else if (use_gui_tool == 0)
 788                 setenv("GIT_MERGETOOL_GUI", "false", 1);
 789
 790         if (difftool_cmd) {
 791                 if (*difftool_cmd)
 792                         setenv("GIT_DIFF_TOOL", difftool_cmd, 1);
 793                 else
 794                         die(_("no <tool> given for --tool=<tool>"));
 795         }
 796
 797         if (extcmd) {
 798                 if (*extcmd)
 799                         setenv("GIT_DIFFTOOL_EXTCMD", extcmd, 1);
 800                 else
 801                         die(_("no <cmd> given for --extcmd=<cmd>"));
 802         }
 803
 804         setenv("GIT_DIFFTOOL_TRUST_EXIT_CODE",
 805                dt_options.trust_exit_code ? "true" : "false", 1);
 806
 807         /*
 808          * In directory diff mode, 'git-difftool--helper' is called once
 809          * to compare the a / b directories. In file diff mode, 'git diff'
 810          * will invoke a separate instance of 'git-difftool--helper' for
 811          * each file that changed.
 812          */
 813         strvec_push(&child.args, "diff");
 814         if (no_index)
 815                 strvec_push(&child.args, "--no-index");
 816         if (dir_diff)
 817                 strvec_pushl(&child.args, "--raw", "--no-abbrev", "-z", NULL);
 818         strvec_pushv(&child.args, argv);
 819
 820         if (dir_diff)
 821                 return run_dir_diff(repo, &dt_options, extcmd, prefix, &child);
 822         return run_file_diff(prompt, prefix, &child);
 823 }