built-in add -i: re-implement `revert` in C

This is a relatively straight-forward port from the Perl version, with
the notable exception that we imitate `git reset -- <paths>` in the C
version rather than the convoluted `git ls-tree HEAD -- <paths> | git
update-index --index-info` followed by `git update-index --force-remove
-- <paths>` for the missed ones.

While at it, we fix the pretty obvious bug where the `revert` command
offers to unstage files that do not have staged changes.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/add-interactive.c b/add-interactive.c
index 1e34e880696939c7bd7e5642a80107839f987a60..adab17a635cd4528bcca9555d4b2d84a650263eb 100644 (file)
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -657,6 +657,114 @@ static int run_update(struct add_i_state *s, const struct pathspec *ps,
        return res;
 }
 
+static void revert_from_diff(struct diff_queue_struct *q,
+                            struct diff_options *opt, void *data)
+{
+       int i, add_flags = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
+
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filespec *one = q->queue[i]->one;
+               struct cache_entry *ce;
+
+               if (!(one->mode && !is_null_oid(&one->oid))) {
+                       remove_file_from_index(opt->repo->index, one->path);
+                       printf(_("note: %s is untracked now.\n"), one->path);
+               } else {
+                       ce = make_cache_entry(opt->repo->index, one->mode,
+                                             &one->oid, one->path, 0, 0);
+                       if (!ce)
+                               die(_("make_cache_entry failed for path '%s'"),
+                                   one->path);
+                       add_index_entry(opt->repo->index, ce, add_flags);
+               }
+       }
+}
+
+static int run_revert(struct add_i_state *s, const struct pathspec *ps,
+                     struct prefix_item_list *files,
+                     struct list_and_choose_options *opts)
+{
+       int res = 0, fd;
+       size_t count, i, j;
+
+       struct object_id oid;
+       int is_initial = !resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &oid,
+                                            NULL);
+       struct lock_file index_lock;
+       const char **paths;
+       struct tree *tree;
+       struct diff_options diffopt = { NULL };
+
+       if (get_modified_files(s->r, INDEX_ONLY, files, ps) < 0)
+               return -1;
+
+       if (!files->items.nr) {
+               putchar('\n');
+               return 0;
+       }
+
+       opts->prompt = N_("Revert");
+       count = list_and_choose(s, files, opts);
+       if (count <= 0)
+               goto finish_revert;
+
+       fd = repo_hold_locked_index(s->r, &index_lock, LOCK_REPORT_ON_ERROR);
+       if (fd < 0) {
+               res = -1;
+               goto finish_revert;
+       }
+
+       if (is_initial)
+               oidcpy(&oid, s->r->hash_algo->empty_tree);
+       else {
+               tree = parse_tree_indirect(&oid);
+               if (!tree) {
+                       res = error(_("Could not parse HEAD^{tree}"));
+                       goto finish_revert;
+               }
+               oidcpy(&oid, &tree->object.oid);
+       }
+
+       ALLOC_ARRAY(paths, count + 1);
+       for (i = j = 0; i < files->items.nr; i++)
+               if (files->selected[i])
+                       paths[j++] = files->items.items[i].string;
+       paths[j] = NULL;
+
+       parse_pathspec(&diffopt.pathspec, 0,
+                      PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH,
+                      NULL, paths);
+
+       diffopt.output_format = DIFF_FORMAT_CALLBACK;
+       diffopt.format_callback = revert_from_diff;
+       diffopt.flags.override_submodule_config = 1;
+       diffopt.repo = s->r;
+
+       if (do_diff_cache(&oid, &diffopt))
+               res = -1;
+       else {
+               diffcore_std(&diffopt);
+               diff_flush(&diffopt);
+       }
+       free(paths);
+       clear_pathspec(&diffopt.pathspec);
+
+       if (!res && write_locked_index(s->r->index, &index_lock,
+                                      COMMIT_LOCK) < 0)
+               res = -1;
+       else
+               res = repo_refresh_and_write_index(s->r, REFRESH_QUIET, 0, 1,
+                                                  NULL, NULL, NULL);
+
+       if (!res)
+               printf(Q_("reverted %d path\n",
+                         "reverted %d paths\n", count), (int)count);
+
+finish_revert:
+       putchar('\n');
+       return res;
+}
+
 static int run_help(struct add_i_state *s, const struct pathspec *unused_ps,
                    struct prefix_item_list *unused_files,
                    struct list_and_choose_options *unused_opts)
@@ -752,6 +860,7 @@ int run_add_i(struct repository *r, const struct pathspec *ps)
        } command_list[] = {
                { "status", run_status },
                { "update", run_update },
+               { "revert", run_revert },
                { "help", run_help },
        };
        struct prefix_item_list commands = PREFIX_ITEM_LIST_INIT;