Replace xmalloc+memset(0) with xcalloc.
[git.git] / sha1_name.c
index f64755f..4f92e12 100644 (file)
@@ -1,5 +1,8 @@
 #include "cache.h"
+#include "tag.h"
 #include "commit.h"
+#include "tree.h"
+#include "blob.h"
 
 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 {
@@ -119,6 +122,9 @@ 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)
 {
@@ -128,27 +134,28 @@ 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 SHORT_NAME_AMBIGUOUS;
        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];
 
-       if (len < 4)
+       if (len < MINIMUM_ABBREV)
                return -1;
        memset(res, 0, 20);
        memset(canonical, 'x', 40);
@@ -171,29 +178,101 @@ 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, 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 ||
+                   (is_null && status != SHORT_NAME_AMBIGUOUS)) {
+                       hex[len] = 0;
+                       return hex;
+               }
+               if (status != SHORT_NAME_AMBIGUOUS)
+                       return NULL;
+               len++;
+       }
+       return NULL;
+}
+
+static int ambiguous_path(const char *path, int len)
+{
+       int slash = 1;
+       int cnt;
+
+       for (cnt = 0; cnt < len; cnt++) {
+               switch (*path++) {
+               case '\0':
+                       break;
+               case '/':
+                       if (slash)
+                               break;
+                       slash = 1;
+                       continue;
+               case '.':
+                       continue;
+               default:
+                       slash = 0;
+                       continue;
+               }
+               break;
+       }
+       return slash;
 }
 
 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;
 
-       for (p = prefix; *p; p++) {
-               char *pathname = git_path("%s/%.*s", *p, len, str);
-               if (!read_ref(pathname, sha1))
-                       return 0;
-       }
+       /* Accept only unambiguous ref paths. */
+       if (ambiguous_path(str, len))
+               return -1;
 
+       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;
 }
 
@@ -248,51 +327,126 @@ static int get_nth_ancestor(const char *name, int len,
        return 0;
 }
 
-static int get_sha1_1(const char *name, int len, unsigned char *sha1)
+static int peel_onion(const char *name, int len, unsigned char *sha1)
 {
-       int parent, ret;
-       const char *cp;
+       unsigned char outer[20];
+       const char *sp;
+       const char *type_string = NULL;
+       struct object *o;
 
-       /* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
-       if (len > 2 && name[len-2] == '^' &&
-           name[len-1] >= '0' && name[len-1] <= '9') {
-               parent = name[len-1] - '0';
-               len -= 2;
+       /*
+        * "ref^{type}" dereferences ref repeatedly until you cannot
+        * dereference anymore, or you get an object of given type,
+        * whichever comes first.  "ref^{}" means just dereference
+        * tags until you get a non-tag.  "ref^0" is a shorthand for
+        * "ref^{commit}".  "commit^{tree}" could be used to find the
+        * top-level tree of the given commit.
+        */
+       if (len < 4 || name[len-1] != '}')
+               return -1;
+
+       for (sp = name + len - 1; name <= sp; sp--) {
+               int ch = *sp;
+               if (ch == '{' && name < sp && sp[-1] == '^')
+                       break;
        }
-       else if (len > 1 && name[len-1] == '^') {
-               parent = 1;
-               len--;
-       } else
-               parent = -1;
+       if (sp <= name)
+               return -1;
 
-       if (parent >= 0)
-               return get_parent(name, len, sha1, parent);
+       sp++; /* beginning of type name, or closing brace for empty */
+       if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
+               type_string = commit_type;
+       else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
+               type_string = tree_type;
+       else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
+               type_string = blob_type;
+       else if (sp[0] == '}')
+               type_string = NULL;
+       else
+               return -1;
+
+       if (get_sha1_1(name, sp - name - 2, outer))
+               return -1;
+
+       o = parse_object(outer);
+       if (!o)
+               return -1;
+       if (!type_string) {
+               o = deref_tag(o, name, sp - name - 2);
+               if (!o || (!o->parsed && !parse_object(o->sha1)))
+                       return -1;
+               memcpy(sha1, o->sha1, 20);
+       }
+       else {
+               /* At this point, the syntax look correct, so
+                * if we do not get the needed object, we should
+                * barf.
+                */
+
+               while (1) {
+                       if (!o || (!o->parsed && !parse_object(o->sha1)))
+                               return -1;
+                       if (o->type == type_string) {
+                               memcpy(sha1, o->sha1, 20);
+                               return 0;
+                       }
+                       if (o->type == tag_type)
+                               o = ((struct tag*) o)->tagged;
+                       else if (o->type == commit_type)
+                               o = &(((struct commit *) o)->tree->object);
+                       else
+                               return error("%.*s: expected %s type, but the object dereferences to %s type",
+                                            len, name, type_string,
+                                            o->type);
+                       if (!o->parsed)
+                               parse_object(o->sha1);
+               }
+       }
+       return 0;
+}
+
+static int get_sha1_1(const char *name, int len, unsigned char *sha1)
+{
+       int ret, has_suffix;
+       const char *cp;
 
        /* "name~3" is "name^^^",
-        * "name~12" is "name^^^^^^^^^^^^", and
         * "name~" and "name~0" are name -- not "name^0"!
+        * "name^" is not "name^0"; it is "name^1".
         */
-       parent = 0;
+       has_suffix = 0;
        for (cp = name + len - 1; name <= cp; cp--) {
                int ch = *cp;
                if ('0' <= ch && ch <= '9')
                        continue;
-               if (ch != '~')
-                       parent = -1;
+               if (ch == '~' || ch == '^')
+                       has_suffix = ch;
                break;
        }
-       if (!parent && *cp == '~') {
+
+       if (has_suffix) {
+               int num = 0;
                int len1 = cp - name;
                cp++;
                while (cp < name + len)
-                       parent = parent * 10 + *cp++ - '0';
-               return get_nth_ancestor(name, len1, sha1, parent);
+                       num = num * 10 + *cp++ - '0';
+               if (has_suffix == '^') {
+                       if (!num && len1 == len - 1)
+                               num = 1;
+                       return get_parent(name, len1, sha1, num);
+               }
+               /* else if (has_suffix == '~') -- goes without saying */
+               return get_nth_ancestor(name, len1, sha1, num);
        }
 
+       ret = peel_onion(name, len, sha1);
+       if (!ret)
+               return 0;
+
        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);
 }
 
 /*