show-branch: optionally use unique prefix as name.

[git.git] / sha1_name.c

diff --git a/sha1_name.c b/sha1_name.c
index f64755fbceea617c424b9b83999eeaa91bf76af1..4e9a052333dcbb538866766f68b4fe18f615fe4d 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -119,6 +119,9 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
        return found;
 }
 
+#define SHORT_NAME_NOT_FOUND (-1)
+#define SHORT_NAME_AMBIGUOUS (-2)
+
 static int find_unique_short_object(int len, char *canonical,
                                    unsigned char *res, unsigned char *sha1)
 {
@@ -128,23 +131,24 @@ static int find_unique_short_object(int len, char *canonical,
        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
        has_packed = find_short_packed_object(len, res, packed_sha1);
        if (!has_unpacked && !has_packed)
-               return -1;
+               return SHORT_NAME_NOT_FOUND;
        if (1 < has_unpacked || 1 < has_packed)
-               return error("short SHA1 %.*s is ambiguous.", len, canonical);
+               return SHORT_NAME_AMBIGUOUS;
        if (has_unpacked != has_packed) {
                memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
                return 0;
        }
        /* Both have unique ones -- do they match? */
        if (memcmp(packed_sha1, unpacked_sha1, 20))
-               return error("short SHA1 %.*s is ambiguous.", len, canonical);
+               return -2;
        memcpy(sha1, packed_sha1, 20);
        return 0;
 }
 
-static int get_short_sha1(const char *name, int len, unsigned char *sha1)
+static int get_short_sha1(const char *name, int len, unsigned char *sha1,
+                         int quietly)
 {
-       int i;
+       int i, status;
        char canonical[40];
        unsigned char res[20];
 
@@ -171,7 +175,29 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1)
                res[i >> 1] |= val;
        }
 
-       return find_unique_short_object(i, canonical, res, sha1);
+       status = find_unique_short_object(i, canonical, res, sha1);
+       if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
+               return error("short SHA1 %.*s is ambiguous.", len, canonical);
+       return status;
+}
+
+const char *find_unique_abbrev(const unsigned char *sha1, int len)
+{
+       int status;
+       static char hex[41];
+       memcpy(hex, sha1_to_hex(sha1), 40);
+       while (len < 40) {
+               unsigned char sha1_ret[20];
+               status = get_short_sha1(hex, len, sha1_ret, 1);
+               if (!status) {
+                       hex[len] = 0;
+                       return hex;
+               }
+               if (status != SHORT_NAME_AMBIGUOUS)
+                       return NULL;
+               len++;
+       }
+       return NULL;
 }
 
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
@@ -292,7 +318,7 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1)
        ret = get_sha1_basic(name, len, sha1);
        if (!ret)
                return 0;
-       return get_short_sha1(name, len, sha1);
+       return get_short_sha1(name, len, sha1, 0);
 }
 
 /*