tag.c: Refactor parse_tag_buffer to be saner to program

[git.git] / tag.c

diff --git a/tag.c b/tag.c
index 52d71bb1bcf1d1478bf177b4cde1c0e732e15a8a..ceb86557c5eedb03cbdc81929b7d109b44d440d5 100644 (file)
--- a/tag.c
+++ b/tag.c
@@ -38,11 +38,11 @@ struct tag *lookup_tag(const unsigned char *sha1)
 
 int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
 {
-       int typelen, taglen;
        unsigned char sha1[20];
-       const char *type_line, *tag_line, *sig_line;
        char type[20];
-       const char *start = data;
+       const char *bufptr = data;
+       const char *tail = bufptr + size;
+       const char *nl;
 
        if (item->object.parsed)
                return 0;
@@ -50,29 +50,19 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
 
        if (size < 64)
                return -1;
-       if (memcmp("object ", data, 7) || get_sha1_hex((char *) data + 7, sha1))
+       if (memcmp("object ", bufptr, 7) || get_sha1_hex(bufptr + 7, sha1) || bufptr[47] != '\n')
                return -1;
+       bufptr += 48; /* "object " + sha1 + "\n" */
 
-       type_line = (char *) data + 48;
-       if (memcmp("\ntype ", type_line-1, 6))
+       if (prefixcmp(bufptr, "type "))
                return -1;
-
-       tag_line = memchr(type_line, '\n', size - (type_line - start));
-       if (!tag_line || memcmp("tag ", ++tag_line, 4))
-               return -1;
-
-       sig_line = memchr(tag_line, '\n', size - (tag_line - start));
-       if (!sig_line)
-               return -1;
-       sig_line++;
-
-       typelen = tag_line - type_line - strlen("type \n");
-       if (typelen >= 20)
+       bufptr += 5;
+       nl = memchr(bufptr, '\n', tail - bufptr);
+       if (!nl || sizeof(type) <= (nl - bufptr))
                return -1;
-       memcpy(type, type_line + 5, typelen);
-       type[typelen] = '\0';
-       taglen = sig_line - tag_line - strlen("tag \n");
-       item->tag = xmemdupz(tag_line + 4, taglen);
+       strncpy(type, bufptr, nl - bufptr);
+       type[nl - bufptr] = '\0';
+       bufptr = nl + 1;
 
        if (!strcmp(type, blob_type)) {
                item->tagged = &lookup_blob(sha1)->object;
@@ -87,6 +77,15 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
                item->tagged = NULL;
        }
 
+       if (prefixcmp(bufptr, "tag "))
+               return -1;
+       bufptr += 4;
+       nl = memchr(bufptr, '\n', tail - bufptr);
+       if (!nl)
+               return -1;
+       item->tag = xmemdupz(bufptr, nl - bufptr);
+       bufptr = nl + 1;
+
        return 0;
 }