tag.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "tree.h"
   5 #include "blob.h"
   6
   7 const char *tag_type = "tag";
   8
   9 struct object *deref_tag(struct object *o, const char *warn, int warnlen)
  10 {
  11         while (o && o->type == OBJ_TAG)
  12                 if (((struct tag *)o)->tagged)
  13                         o = parse_object(((struct tag *)o)->tagged->sha1);
  14                 else
  15                         o = NULL;
  16         if (!o && warn) {
  17                 if (!warnlen)
  18                         warnlen = strlen(warn);
  19                 error("missing object referenced by '%.*s'", warnlen, warn);
  20         }
  21         return o;
  22 }
  23
  24 struct tag *lookup_tag(const unsigned char *sha1)
  25 {
  26         struct object *obj = lookup_object(sha1);
  27         if (!obj)
  28                 return create_object(sha1, OBJ_TAG, alloc_tag_node());
  29         if (!obj->type)
  30                 obj->type = OBJ_TAG;
  31         if (obj->type != OBJ_TAG) {
  32                 error("Object %s is a %s, not a tag",
  33                       sha1_to_hex(sha1), typename(obj->type));
  34                 return NULL;
  35         }
  36         return (struct tag *) obj;
  37 }
  38
  39 int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
  40 {
  41         unsigned char sha1[20];
  42         char type[20];
  43         const char *bufptr = data;
  44         const char *tail = bufptr + size;
  45         const char *nl;
  46
  47         if (item->object.parsed)
  48                 return 0;
  49         item->object.parsed = 1;
  50
  51         if (size < 64)
  52                 return -1;
  53         if (memcmp("object ", bufptr, 7) || get_sha1_hex(bufptr + 7, sha1) || bufptr[47] != '\n')
  54                 return -1;
  55         bufptr += 48; /* "object " + sha1 + "\n" */
  56
  57         if (prefixcmp(bufptr, "type "))
  58                 return -1;
  59         bufptr += 5;
  60         nl = memchr(bufptr, '\n', tail - bufptr);
  61         if (!nl || sizeof(type) <= (nl - bufptr))
  62                 return -1;
  63         strncpy(type, bufptr, nl - bufptr);
  64         type[nl - bufptr] = '\0';
  65         bufptr = nl + 1;
  66
  67         if (!strcmp(type, blob_type)) {
  68                 item->tagged = &lookup_blob(sha1)->object;
  69         } else if (!strcmp(type, tree_type)) {
  70                 item->tagged = &lookup_tree(sha1)->object;
  71         } else if (!strcmp(type, commit_type)) {
  72                 item->tagged = &lookup_commit(sha1)->object;
  73         } else if (!strcmp(type, tag_type)) {
  74                 item->tagged = &lookup_tag(sha1)->object;
  75         } else {
  76                 error("Unknown type %s", type);
  77                 item->tagged = NULL;
  78         }
  79
  80         if (prefixcmp(bufptr, "tag "))
  81                 return -1;
  82         bufptr += 4;
  83         nl = memchr(bufptr, '\n', tail - bufptr);
  84         if (!nl)
  85                 return -1;
  86         item->tag = xmemdupz(bufptr, nl - bufptr);
  87         bufptr = nl + 1;
  88
  89         return 0;
  90 }
  91
  92 int parse_tag(struct tag *item)
  93 {
  94         enum object_type type;
  95         void *data;
  96         unsigned long size;
  97         int ret;
  98
  99         if (item->object.parsed)
 100                 return 0;
 101         data = read_sha1_file(item->object.sha1, &type, &size);
 102         if (!data)
 103                 return error("Could not read %s",
 104                              sha1_to_hex(item->object.sha1));
 105         if (type != OBJ_TAG) {
 106                 free(data);
 107                 return error("Object %s not a tag",
 108                              sha1_to_hex(item->object.sha1));
 109         }
 110         ret = parse_tag_buffer(item, data, size);
 111         free(data);
 112         return ret;
 113 }