Make git-diff-cache skip any comparisons which don't match pathspec

This brings all the same pathspec optimizations that git-diff-tree does
to git-diff-cache.

diff --git a/diff-cache.c b/diff-cache.c
index be9222288fb6a6ecfdd4c91f6e386e9baf1c8f60..37c6eb5804ec7a454b0df83809e0208bcbd1b766 100644 (file)
--- a/diff-cache.c
+++ b/diff-cache.c
@@ -87,12 +87,37 @@ static int show_modified(struct cache_entry *old,
        return 0;
 }
 
-static int diff_cache(struct cache_entry **ac, int entries)
+static int ce_path_match(const struct cache_entry *ce, const char **pathspec)
+{
+       const char *match, *name;
+       int len;
+
+       if (!pathspec)
+               return 1;
+
+       len = ce_namelen(ce);
+       name = ce->name;
+       while ((match = *pathspec++) != NULL) {
+               int matchlen = strlen(match);
+               if (matchlen > len)
+                       continue;
+               if (memcmp(name, match, matchlen))
+                       continue;
+               if (name[matchlen] == '/' || !name[matchlen])
+                       return 1;
+       }
+       return 0;
+}
+
+static int diff_cache(struct cache_entry **ac, int entries, const char **pathspec)
 {
        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 */
@@ -130,6 +155,7 @@ static int diff_cache(struct cache_entry **ac, int entries)
                        die("impossible cache entry stage");
                }
 
+skip_entry:
                /*
                 * Ignore all the different stages for this file,
                 * we've handled the relevant cases now.
@@ -281,7 +307,7 @@ int main(int argc, const char **argv)
        if (read_tree(tree, size, 1, pathspec))
                die("unable to read tree object %s", tree_name);
 
-       ret = diff_cache(active_cache, active_nr);
+       ret = diff_cache(active_cache, active_nr, pathspec);
 
        diffcore_std(pathspec,
                     detect_rename, diff_score_opt,