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 object *deref_tag_noverify(struct object *o)
  28 {
  29         while (o && o->type == OBJ_TAG) {
  30                 o = parse_object(o->sha1);
  31                 if (o && o->type == OBJ_TAG && ((struct tag *)o)->tagged)
  32                         o = ((struct tag *)o)->tagged;
  33                 else
  34                         o = NULL;
  35         }
  36         return o;
  37 }
  38
  39 struct tag *lookup_tag(const unsigned char *sha1)
  40 {
  41         struct object *obj = lookup_object(sha1);
  42         if (!obj)
  43                 return create_object(sha1, alloc_tag_node());
  44         return object_as_type(obj, OBJ_TAG, 0);
  45 }
  46
  47 static unsigned long parse_tag_date(const char *buf, const char *tail)
  48 {
  49         const char *dateptr;
  50
  51         while (buf < tail && *buf++ != '>')
  52                 /* nada */;
  53         if (buf >= tail)
  54                 return 0;
  55         dateptr = buf;
  56         while (buf < tail && *buf++ != '\n')
  57                 /* nada */;
  58         if (buf >= tail)
  59                 return 0;
  60         /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  61         return strtoul(dateptr, NULL, 10);
  62 }
  63
  64 int parse_tag_buffer(struct tag *item, const void *data, unsigned long size)
  65 {
  66         unsigned char sha1[20];
  67         char type[20];
  68         const char *bufptr = data;
  69         const char *tail = bufptr + size;
  70         const char *nl;
  71
  72         if (item->object.parsed)
  73                 return 0;
  74         item->object.parsed = 1;
  75
  76         if (size < 64)
  77                 return -1;
  78         if (memcmp("object ", bufptr, 7) || get_sha1_hex(bufptr + 7, sha1) || bufptr[47] != '\n')
  79                 return -1;
  80         bufptr += 48; /* "object " + sha1 + "\n" */
  81
  82         if (!starts_with(bufptr, "type "))
  83                 return -1;
  84         bufptr += 5;
  85         nl = memchr(bufptr, '\n', tail - bufptr);
  86         if (!nl || sizeof(type) <= (nl - bufptr))
  87                 return -1;
  88         strncpy(type, bufptr, nl - bufptr);
  89         type[nl - bufptr] = '\0';
  90         bufptr = nl + 1;
  91
  92         if (!strcmp(type, blob_type)) {
  93                 item->tagged = &lookup_blob(sha1)->object;
  94         } else if (!strcmp(type, tree_type)) {
  95                 item->tagged = &lookup_tree(sha1)->object;
  96         } else if (!strcmp(type, commit_type)) {
  97                 item->tagged = &lookup_commit(sha1)->object;
  98         } else if (!strcmp(type, tag_type)) {
  99                 item->tagged = &lookup_tag(sha1)->object;
 100         } else {
 101                 error("Unknown type %s", type);
 102                 item->tagged = NULL;
 103         }
 104
 105         if (bufptr + 4 < tail && starts_with(bufptr, "tag "))
 106                 ;               /* good */
 107         else
 108                 return -1;
 109         bufptr += 4;
 110         nl = memchr(bufptr, '\n', tail - bufptr);
 111         if (!nl)
 112                 return -1;
 113         item->tag = xmemdupz(bufptr, nl - bufptr);
 114         bufptr = nl + 1;
 115
 116         if (bufptr + 7 < tail && starts_with(bufptr, "tagger "))
 117                 item->date = parse_tag_date(bufptr, tail);
 118         else
 119                 item->date = 0;
 120
 121         return 0;
 122 }
 123
 124 int parse_tag(struct tag *item)
 125 {
 126         enum object_type type;
 127         void *data;
 128         unsigned long size;
 129         int ret;
 130
 131         if (item->object.parsed)
 132                 return 0;
 133         data = read_sha1_file(item->object.sha1, &type, &size);
 134         if (!data)
 135                 return error("Could not read %s",
 136                              sha1_to_hex(item->object.sha1));
 137         if (type != OBJ_TAG) {
 138                 free(data);
 139                 return error("Object %s not a tag",
 140                              sha1_to_hex(item->object.sha1));
 141         }
 142         ret = parse_tag_buffer(item, data, size);
 143         free(data);
 144         return ret;
 145 }
 146
 147 /*
 148  * Look at a signed tag object, and return the offset where
 149  * the embedded detached signature begins, or the end of the
 150  * data when there is no such signature.
 151  */
 152 size_t parse_signature(const char *buf, unsigned long size)
 153 {
 154         char *eol;
 155         size_t len = 0;
 156         while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
 157                         !starts_with(buf + len, PGP_MESSAGE)) {
 158                 eol = memchr(buf + len, '\n', size - len);
 159                 len += eol ? eol - (buf + len) + 1 : size - len;
 160         }
 161         return len;
 162 }