traverse_trees(): allow pruning with pathspec

The traverse_trees() machinery is primarily meant for merging two (or
more) trees, and because a merge is a full tree operation, it doesn't
support any pruning with pathspec.

Since d1f2d7e (Make run_diff_index() use unpack_trees(), not read_tree(),
2008-01-19), however, we use unpack_trees() to traverse_trees() callchain
to perform "diff-index", which could waste a lot of work traversing trees
outside the user-supplied pathspec, only to discard at the blob comparison
level in diff-lib.c::oneway_diff() which is way too late.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/tree-walk.c b/tree-walk.c
index 33f749e1e77484694e7b8f40a65755a7818c4abb..808bb55ba3f21d113e6358f6874e2e20cb33bbea 100644 (file)
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -309,6 +309,18 @@ static void free_extended_entry(struct tree_desc_x *t)
        }
 }
 
+static inline int prune_traversal(struct name_entry *e,
+                                 struct traverse_info *info,
+                                 struct strbuf *base,
+                                 int still_interesting)
+{
+       if (!info->pathspec || still_interesting == 2)
+               return 2;
+       if (still_interesting < 0)
+               return still_interesting;
+       return tree_entry_interesting(e, base, 0, info->pathspec);
+}
+
 int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 {
        int ret = 0;
@@ -316,10 +328,18 @@ int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
        struct name_entry *entry = xmalloc(n*sizeof(*entry));
        int i;
        struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
+       struct strbuf base = STRBUF_INIT;
+       int interesting = 1;
 
        for (i = 0; i < n; i++)
                tx[i].d = t[i];
 
+       if (info->prev) {
+               strbuf_grow(&base, info->pathlen);
+               make_traverse_path(base.buf, info->prev, &info->name);
+               base.buf[info->pathlen-1] = '/';
+               strbuf_setlen(&base, info->pathlen);
+       }
        for (;;) {
                unsigned long mask, dirmask;
                const char *first = NULL;
@@ -376,16 +396,22 @@ int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
                        mask |= 1ul << i;
                        if (S_ISDIR(entry[i].mode))
                                dirmask |= 1ul << i;
+                       e = &entry[i];
                }
                if (!mask)
                        break;
-               ret = info->fn(n, mask, dirmask, entry, info);
-               if (ret < 0) {
-                       error = ret;
-                       if (!info->show_all_errors)
-                               break;
+               interesting = prune_traversal(e, info, &base, interesting);
+               if (interesting < 0)
+                       break;
+               if (interesting) {
+                       ret = info->fn(n, mask, dirmask, entry, info);
+                       if (ret < 0) {
+                               error = ret;
+                               if (!info->show_all_errors)
+                                       break;
+                       }
+                       mask &= ret;
                }
-               mask &= ret;
                ret = 0;
                for (i = 0; i < n; i++)
                        if (mask & (1ul << i))
@@ -395,6 +421,7 @@ int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
        for (i = 0; i < n; i++)
                free_extended_entry(tx + i);
        free(tx);
+       strbuf_release(&base);
        return error;
 }
 

diff --git a/tree-walk.h b/tree-walk.h
index 39524b7dba6a1d0b63c4cd2b42db59a27a030b21..0089581e1dd55800302799a7381d4a7ad01bd79d 100644 (file)
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -44,6 +44,7 @@ struct traverse_info {
        struct traverse_info *prev;
        struct name_entry name;
        int pathlen;
+       struct pathspec *pathspec;
 
        unsigned long conflicts;
        traverse_callback_t fn;