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         int typelen, taglen;
  42         unsigned char sha1[20];
  43         const char *type_line, *tag_line, *sig_line;
  44         char type[20];
  45         const char *start = data;
  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 ", data, 7) || get_sha1_hex((char *) data + 7, sha1))
  54                 return -1;
  55
  56         type_line = (char *) data + 48;
  57         if (memcmp("\ntype ", type_line-1, 6))
  58                 return -1;
  59
  60         tag_line = memchr(type_line, '\n', size - (type_line - start));
  61         if (!tag_line || memcmp("tag ", ++tag_line, 4))
  62                 return -1;
  63
  64         sig_line = memchr(tag_line, '\n', size - (tag_line - start));
  65         if (!sig_line)
  66                 return -1;
  67         sig_line++;
  68
  69         typelen = tag_line - type_line - strlen("type \n");
  70         if (typelen >= 20)
  71                 return -1;
  72         memcpy(type, type_line + 5, typelen);
  73         type[typelen] = '\0';
  74         taglen = sig_line - tag_line - strlen("tag \n");
  75         item->tag = xmemdupz(tag_line + 4, taglen);
  76
  77         if (!strcmp(type, blob_type)) {
  78                 item->tagged = &lookup_blob(sha1)->object;
  79         } else if (!strcmp(type, tree_type)) {
  80                 item->tagged = &lookup_tree(sha1)->object;
  81         } else if (!strcmp(type, commit_type)) {
  82                 item->tagged = &lookup_commit(sha1)->object;
  83         } else if (!strcmp(type, tag_type)) {
  84                 item->tagged = &lookup_tag(sha1)->object;
  85         } else {
  86                 error("Unknown type %s", type);
  87                 item->tagged = NULL;
  88         }
  89
  90         return 0;
  91 }
  92
  93 int parse_tag(struct tag *item)
  94 {
  95         enum object_type type;
  96         void *data;
  97         unsigned long size;
  98         int ret;
  99
 100         if (item->object.parsed)
 101                 return 0;
 102         data = read_sha1_file(item->object.sha1, &type, &size);
 103         if (!data)
 104                 return error("Could not read %s",
 105                              sha1_to_hex(item->object.sha1));
 106         if (type != OBJ_TAG) {
 107                 free(data);
 108                 return error("Object %s not a tag",
 109                              sha1_to_hex(item->object.sha1));
 110         }
 111         ret = parse_tag_buffer(item, data, size);
 112         free(data);
 113         return ret;
 114 }