tag.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "tree.h"
   5 #include "blob.h"
   6
   7 #define PGP_SIGNATURE "-----BEGIN PGP SIGNATURE-----"
   8 #define PGP_MESSAGE "-----BEGIN PGP MESSAGE-----"
   9
  10 const char *tag_type = "tag";
  11
  12 struct object *deref_tag(struct object *o, const char *warn, int warnlen)
  13 {
  14         while (o && o->type == OBJ_TAG)
  15                 if (((struct tag *)o)->tagged)
  16                         o = parse_object(((struct tag *)o)->tagged->sha1);
  17                 else
  18                         o = NULL;
  19         if (!o && warn) {
  20                 if (!warnlen)
  21                         warnlen = strlen(warn);
  22                 error("missing object referenced by '%.*s'", warnlen, warn);
  23         }
  24         return o;
  25 }
  26
  27 struct tag *lookup_tag(const unsigned char *sha1)
  28 {
  29         struct object *obj = lookup_object(sha1);
  30         if (!obj)
  31                 return create_object(sha1, OBJ_TAG, alloc_tag_node());
  32         if (!obj->type)
  33                 obj->type = OBJ_TAG;
  34         if (obj->type != OBJ_TAG) {
  35                 error("Object %s is a %s, not a tag",
  36                       sha1_to_hex(sha1), typename(obj->type));
  37                 return NULL;
  38         }
  39         return (struct tag *) obj;
  40 }
  41
  42 static unsigned long parse_tag_date(const char *buf, const char *tail)
  43 {
  44         const char *dateptr;
  45
  46         while (buf < tail && *buf++ != '>')
  47                 /* nada */;
  48         if (buf >= tail)
  49                 return 0;
  50         dateptr = buf;
  51         while (buf < tail && *buf++ != '\n')
  52                 /* nada */;
  53         if (buf >= tail)
  54                 return 0;
  55         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  56         return strtoul(dateptr, NULL, 10);
  57 }
  58
  59 int parse_tag_buffer(struct tag *item, const void *data, unsigned long size)
  60 {
  61         unsigned char sha1[20];
  62         char type[20];
  63         const char *bufptr = data;
  64         const char *tail = bufptr + size;
  65         const char *nl;
  66
  67         if (item->object.parsed)
  68                 return 0;
  69         item->object.parsed = 1;
  70
  71         if (size < 64)
  72                 return -1;
  73         if (memcmp("object ", bufptr, 7) || get_sha1_hex(bufptr + 7, sha1) || bufptr[47] != '\n')
  74                 return -1;
  75         bufptr += 48; /* "object " + sha1 + "\n" */
  76
  77         if (prefixcmp(bufptr, "type "))
  78                 return -1;
  79         bufptr += 5;
  80         nl = memchr(bufptr, '\n', tail - bufptr);
  81         if (!nl || sizeof(type) <= (nl - bufptr))
  82                 return -1;
  83         strncpy(type, bufptr, nl - bufptr);
  84         type[nl - bufptr] = '\0';
  85         bufptr = nl + 1;
  86
  87         if (!strcmp(type, blob_type)) {
  88                 item->tagged = &lookup_blob(sha1)->object;
  89         } else if (!strcmp(type, tree_type)) {
  90                 item->tagged = &lookup_tree(sha1)->object;
  91         } else if (!strcmp(type, commit_type)) {
  92                 item->tagged = &lookup_commit(sha1)->object;
  93         } else if (!strcmp(type, tag_type)) {
  94                 item->tagged = &lookup_tag(sha1)->object;
  95         } else {
  96                 error("Unknown type %s", type);
  97                 item->tagged = NULL;
  98         }
  99
 100         if (bufptr + 4 < tail && !prefixcmp(bufptr, "tag "))
 101                 ;               /* good */
 102         else
 103                 return -1;
 104         bufptr += 4;
 105         nl = memchr(bufptr, '\n', tail - bufptr);
 106         if (!nl)
 107                 return -1;
 108         item->tag = xmemdupz(bufptr, nl - bufptr);
 109         bufptr = nl + 1;
 110
 111         if (bufptr + 7 < tail && !prefixcmp(bufptr, "tagger "))
 112                 item->date = parse_tag_date(bufptr, tail);
 113         else
 114                 item->date = 0;
 115
 116         return 0;
 117 }
 118
 119 int parse_tag(struct tag *item)
 120 {
 121         enum object_type type;
 122         void *data;
 123         unsigned long size;
 124         int ret;
 125
 126         if (item->object.parsed)
 127                 return 0;
 128         data = read_sha1_file(item->object.sha1, &type, &size);
 129         if (!data)
 130                 return error("Could not read %s",
 131                              sha1_to_hex(item->object.sha1));
 132         if (type != OBJ_TAG) {
 133                 free(data);
 134                 return error("Object %s not a tag",
 135                              sha1_to_hex(item->object.sha1));
 136         }
 137         ret = parse_tag_buffer(item, data, size);
 138         free(data);
 139         return ret;
 140 }
 141
 142 /*
 143  * Look at a signed tag object, and return the offset where
 144  * the embedded detached signature begins, or the end of the
 145  * data when there is no such signature.
 146  */
 147 size_t parse_signature(const char *buf, unsigned long size)
 148 {
 149         char *eol;
 150         size_t len = 0;
 151         while (len < size && prefixcmp(buf + len, PGP_SIGNATURE) &&
 152                         prefixcmp(buf + len, PGP_MESSAGE)) {
 153                 eol = memchr(buf + len, '\n', size - len);
 154                 len += eol ? eol - (buf + len) + 1 : size - len;
 155         }
 156         return len;
 157 }