index: make the index file format extensible.

diff --git a/sha1_name.c b/sha1_name.c
index fa85d8a88d31219cef5bed195044327459f9162b..345935bb2beddac7b86d5b989ea1492f58a777d8 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -3,6 +3,7 @@
 #include "commit.h"
 #include "tree.h"
 #include "blob.h"
+#include "tree-walk.h"
 
 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 {
@@ -186,16 +187,18 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 
 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 {
-       int status;
+       int status, is_null;
        static char hex[41];
 
+       is_null = !memcmp(sha1, null_sha1, 20);
        memcpy(hex, sha1_to_hex(sha1), 40);
        if (len == 40)
                return hex;
        while (len < 40) {
                unsigned char sha1_ret[20];
                status = get_short_sha1(hex, len, sha1_ret, 1);
-               if (!status) {
+               if (!status ||
+                   (is_null && status != SHORT_NAME_AMBIGUOUS)) {
                        hex[len] = 0;
                        return hex;
                }
@@ -233,14 +236,21 @@ static int ambiguous_path(const char *path, int len)
 
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 {
-       static const char *prefix[] = {
-               "",
-               "refs",
-               "refs/tags",
-               "refs/heads",
+       static const char *fmt[] = {
+               "%.*s",
+               "refs/%.*s",
+               "refs/tags/%.*s",
+               "refs/heads/%.*s",
+               "refs/remotes/%.*s",
+               "refs/remotes/%.*s/HEAD",
                NULL
        };
        const char **p;
+       const char *warning = "warning: refname '%.*s' is ambiguous.\n";
+       char *pathname;
+       int already_found = 0;
+       unsigned char *this_result;
+       unsigned char sha1_from_ref[20];
 
        if (len == 40 && !get_sha1_hex(str, sha1))
                return 0;
@@ -249,11 +259,21 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
        if (ambiguous_path(str, len))
                return -1;
 
-       for (p = prefix; *p; p++) {
-               char *pathname = git_path("%s/%.*s", *p, len, str);
-               if (!read_ref(pathname, sha1))
-                       return 0;
+       for (p = fmt; *p; p++) {
+               this_result = already_found ? sha1_from_ref : sha1;
+               pathname = git_path(*p, len, str);
+               if (!read_ref(pathname, this_result)) {
+                       if (warn_ambiguous_refs) {
+                               if (already_found)
+                                       fprintf(stderr, warning, len, str);
+                               already_found++;
+                       }
+                       else
+                               return 0;
+               }
        }
+       if (already_found)
+               return 0;
        return -1;
 }
 
@@ -436,6 +456,19 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1)
  */
 int get_sha1(const char *name, unsigned char *sha1)
 {
+       int ret;
+       unsigned unused;
+
        prepare_alt_odb();
-       return get_sha1_1(name, strlen(name), sha1);
+       ret = get_sha1_1(name, strlen(name), sha1);
+       if (ret < 0) {
+               const char *cp = strchr(name, ':');
+               if (cp) {
+                       unsigned char tree_sha1[20];
+                       if (!get_sha1_1(name, cp-name, tree_sha1))
+                               return get_tree_entry(tree_sha1, cp+1, sha1,
+                                                     &unused);
+               }
+       }
+       return ret;
 }