pack-object: slightly more efficient
[gitweb.git] / diff-lib.c
index a28dd3dca79ab93f45cb0be0ea6e662ab28447f1..2183b41b03d08092ba6d98a642757640b86710d6 100644 (file)
@@ -131,3 +131,214 @@ int run_diff_files(struct rev_info *revs, int silent_on_removed)
        return 0;
 }
 
+/*
+ * diff-index
+ */
+
+/* A file entry went away or appeared */
+static void diff_index_show_file(struct rev_info *revs,
+                                const char *prefix,
+                                struct cache_entry *ce,
+                                unsigned char *sha1, unsigned int mode)
+{
+       diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
+                      sha1, ce->name, NULL);
+}
+
+static int get_stat_data(struct cache_entry *ce,
+                        unsigned char **sha1p,
+                        unsigned int *modep,
+                        int cached, int match_missing)
+{
+       unsigned char *sha1 = ce->sha1;
+       unsigned int mode = ce->ce_mode;
+
+       if (!cached) {
+               static unsigned char no_sha1[20];
+               int changed;
+               struct stat st;
+               if (lstat(ce->name, &st) < 0) {
+                       if (errno == ENOENT && match_missing) {
+                               *sha1p = sha1;
+                               *modep = mode;
+                               return 0;
+                       }
+                       return -1;
+               }
+               changed = ce_match_stat(ce, &st, 0);
+               if (changed) {
+                       mode = create_ce_mode(st.st_mode);
+                       if (!trust_executable_bit && S_ISREG(st.st_mode))
+                               mode = ce->ce_mode;
+                       sha1 = no_sha1;
+               }
+       }
+
+       *sha1p = sha1;
+       *modep = mode;
+       return 0;
+}
+
+static void show_new_file(struct rev_info *revs,
+                         struct cache_entry *new,
+                         int cached, int match_missing)
+{
+       unsigned char *sha1;
+       unsigned int mode;
+
+       /* 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)
+               return;
+
+       diff_index_show_file(revs, "+", new, sha1, mode);
+}
+
+static int show_modified(struct rev_info *revs,
+                        struct cache_entry *old,
+                        struct cache_entry *new,
+                        int report_missing,
+                        int cached, int match_missing)
+{
+       unsigned int mode, oldmode;
+       unsigned char *sha1;
+
+       if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
+               if (report_missing)
+                       diff_index_show_file(revs, "-", old,
+                                            old->sha1, old->ce_mode);
+               return -1;
+       }
+
+       oldmode = old->ce_mode;
+       if (mode == oldmode && !memcmp(sha1, old->sha1, 20) &&
+           !revs->diffopt.find_copies_harder)
+               return 0;
+
+       mode = ntohl(mode);
+       oldmode = ntohl(oldmode);
+
+       diff_change(&revs->diffopt, oldmode, mode,
+                   old->sha1, sha1, old->name, NULL);
+       return 0;
+}
+
+static int diff_cache(struct rev_info *revs,
+                     struct cache_entry **ac, int entries,
+                     const char **pathspec,
+                     int cached, int match_missing)
+{
+       while (entries) {
+               struct cache_entry *ce = *ac;
+               int same = (entries > 1) && ce_same_name(ce, ac[1]);
+
+               if (!ce_path_match(ce, pathspec))
+                       goto skip_entry;
+
+               switch (ce_stage(ce)) {
+               case 0:
+                       /* No stage 1 entry? That means it's a new file */
+                       if (!same) {
+                               show_new_file(revs, ce, cached, match_missing);
+                               break;
+                       }
+                       /* Show difference between old and new */
+                       show_modified(revs,ac[1], ce, 1,
+                                     cached, match_missing);
+                       break;
+               case 1:
+                       /* No stage 3 (merge) entry?
+                        * That means it's been deleted.
+                        */
+                       if (!same) {
+                               diff_index_show_file(revs, "-", ce,
+                                                    ce->sha1, ce->ce_mode);
+                               break;
+                       }
+                       /* We come here with ce pointing at stage 1
+                        * (original tree) and ac[1] pointing at stage
+                        * 3 (unmerged).  show-modified with
+                        * report-missing set to false does not say the
+                        * file is deleted but reports true if work
+                        * tree does not have it, in which case we
+                        * fall through to report the unmerged state.
+                        * Otherwise, we show the differences between
+                        * the original tree and the work tree.
+                        */
+                       if (!cached &&
+                           !show_modified(revs, ce, ac[1], 0,
+                                          cached, match_missing))
+                               break;
+                       /* fallthru */
+               case 3:
+                       diff_unmerge(&revs->diffopt, ce->name);
+                       break;
+
+               default:
+                       die("impossible cache entry stage");
+               }
+
+skip_entry:
+               /*
+                * Ignore all the different stages for this file,
+                * we've handled the relevant cases now.
+                */
+               do {
+                       ac++;
+                       entries--;
+               } while (entries && ce_same_name(ce, ac[0]));
+       }
+       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 |= htons(CE_STAGEMASK);
+       }
+}
+
+int run_diff_index(struct rev_info *revs, int cached)
+{
+       int ret;
+       struct object *ent;
+       struct tree *tree;
+       const char *tree_name;
+       int match_missing = 0;
+
+       /* 
+        * Backward compatibility wart - "diff-index -m" does
+        * not mean "do not ignore merges", but totally different.
+        */
+       if (!revs->ignore_merges)
+               match_missing = 1;
+
+       if (read_cache() < 0) {
+               perror("read_cache");
+               return -1;
+       }
+       mark_merge_entries();
+
+       ent = revs->pending_objects->item;
+       tree_name = revs->pending_objects->name;
+       tree = parse_tree_indirect(ent->sha1);
+       if (!tree)
+               return error("bad tree object %s", tree_name);
+       if (read_tree(tree, 1, revs->prune_data))
+               return error("unable to read tree object %s", tree_name);
+       ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
+                        cached, match_missing);
+       diffcore_std(&revs->diffopt);
+       diff_flush(&revs->diffopt);
+       return ret;
+}