add more informative error messages to git-mktag

diff --git a/tree-walk.c b/tree-walk.c
index 0735f4046dd8524e92e97a8ce6cc5c0991208b01..9f7abb7cb352241191e395e3967730f3bdcf6d55 100644 (file)
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "tree-walk.h"
+#include "tree.h"
 
 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
 {
@@ -7,7 +8,7 @@ void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
        void *buf = NULL;
 
        if (sha1) {
-               buf = read_object_with_reference(sha1, "tree", &size, NULL);
+               buf = read_object_with_reference(sha1, tree_type, &size, NULL);
                if (!buf)
                        die("unable to read tree %s", sha1_to_hex(sha1));
        }
@@ -114,3 +115,53 @@ void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callb
        free(entry);
 }
 
+static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
+{
+       int namelen = strlen(name);
+       while (t->size) {
+               const char *entry;
+               const unsigned char *sha1;
+               int entrylen, cmp;
+
+               sha1 = tree_entry_extract(t, &entry, mode);
+               update_tree_entry(t);
+               entrylen = strlen(entry);
+               if (entrylen > namelen)
+                       continue;
+               cmp = memcmp(name, entry, entrylen);
+               if (cmp > 0)
+                       continue;
+               if (cmp < 0)
+                       break;
+               if (entrylen == namelen) {
+                       memcpy(result, sha1, 20);
+                       return 0;
+               }
+               if (name[entrylen] != '/')
+                       continue;
+               if (!S_ISDIR(*mode))
+                       break;
+               if (++entrylen == namelen) {
+                       memcpy(result, sha1, 20);
+                       return 0;
+               }
+               return get_tree_entry(sha1, name + entrylen, result, mode);
+       }
+       return -1;
+}
+
+int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
+{
+       int retval;
+       void *tree;
+       struct tree_desc t;
+
+       tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
+       if (!tree)
+               return -1;
+       t.buf = tree;
+       retval = find_tree_entry(&t, name, sha1, mode);
+       free(tree);
+       return retval;
+}
+