Make 'traverse_tree()' use linked structure rather than 'const char *base'

This makes the calling convention a bit less obvious, but a lot more
flexible.  Instead of allocating and extending a new 'base' string, we
just link the top-most name into a linked list of the 'info' structure
when traversing a subdirectory, and we can generate the basename by
following the list.

Perhaps even more importantly, the linked list of info structures also
gives us a place to naturally save off other information than just the
directory name.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 33 insertions, 2 deletions

diff --git a/tree-walk.c b/tree-walk.c
index 142205ddc3..f9f7d225e9 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -104,7 +104,38 @@ int tree_entry(struct tree_desc *desc, struct name_entry *entry)
 	return 1;
 }
 
-void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
+void setup_traverse_info(struct traverse_info *info, const char *base)
+{
+	int pathlen = strlen(base);
+
+	memset(info, 0, sizeof(*info));
+	if (pathlen && base[pathlen-1] == '/')
+		pathlen--;
+	info->pathlen = pathlen ? pathlen + 1 : 0;
+	info->name.path = base;
+	info->name.sha1 = (void *)(base + pathlen + 1);
+}
+
+char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
+{
+	int len = tree_entry_len(n->path, n->sha1);
+	int pathlen = info->pathlen;
+
+	path[pathlen + len] = 0;
+	for (;;) {
+		memcpy(path + pathlen, n->path, len);
+		if (!pathlen)
+			break;
+		path[--pathlen] = '/';
+		n = &info->name;
+		len = tree_entry_len(n->path, n->sha1);
+		info = info->prev;
+		pathlen -= len;
+	}
+	return path;
+}
+
+void traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
 {
 	struct name_entry *entry = xmalloc(n*sizeof(*entry));
 
@@ -150,7 +181,7 @@ void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callb
 			}
 			entry_clear(entry + i);
 		}
-		callback(n, mask, entry, base);
+		info->fn(n, mask, entry, info);
 	}
 	free(entry);
 }