pack-refs.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "tag.h"
   4 #include "pack-refs.h"
   5
   6 struct ref_to_prune {
   7         struct ref_to_prune *next;
   8         unsigned char sha1[20];
   9         char name[FLEX_ARRAY];
  10 };
  11
  12 struct pack_refs_cb_data {
  13         unsigned int flags;
  14         struct ref_to_prune *ref_to_prune;
  15         FILE *refs_file;
  16 };
  17
  18 static int do_not_prune(int flags)
  19 {
  20         /* If it is already packed or if it is a symref,
  21          * do not prune it.
  22          */
  23         return (flags & (REF_ISSYMREF|REF_ISPACKED));
  24 }
  25
  26 static int handle_one_ref(const char *path, const unsigned char *sha1,
  27                           int flags, void *cb_data)
  28 {
  29         struct pack_refs_cb_data *cb = cb_data;
  30         int is_tag_ref;
  31
  32         /* Do not pack the symbolic refs */
  33         if ((flags & REF_ISSYMREF))
  34                 return 0;
  35         is_tag_ref = !prefixcmp(path, "refs/tags/");
  36
  37         /* ALWAYS pack refs that were already packed or are tags */
  38         if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref && !(flags & REF_ISPACKED))
  39                 return 0;
  40
  41         fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path);
  42         if (is_tag_ref) {
  43                 struct object *o = parse_object(sha1);
  44                 if (o->type == OBJ_TAG) {
  45                         o = deref_tag(o, path, 0);
  46                         if (o)
  47                                 fprintf(cb->refs_file, "^%s\n",
  48                                         sha1_to_hex(o->sha1));
  49                 }
  50         }
  51
  52         if ((cb->flags & PACK_REFS_PRUNE) && !do_not_prune(flags)) {
  53                 int namelen = strlen(path) + 1;
  54                 struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
  55                 hashcpy(n->sha1, sha1);
  56                 strcpy(n->name, path);
  57                 n->next = cb->ref_to_prune;
  58                 cb->ref_to_prune = n;
  59         }
  60         return 0;
  61 }
  62
  63 /* make sure nobody touched the ref, and unlink */
  64 static void prune_ref(struct ref_to_prune *r)
  65 {
  66         struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
  67
  68         if (lock) {
  69                 unlink(git_path("%s", r->name));
  70                 unlock_ref(lock);
  71         }
  72 }
  73
  74 static void prune_refs(struct ref_to_prune *r)
  75 {
  76         while (r) {
  77                 prune_ref(r);
  78                 r = r->next;
  79         }
  80 }
  81
  82 static struct lock_file packed;
  83
  84 int pack_refs(unsigned int flags)
  85 {
  86         int fd;
  87         struct pack_refs_cb_data cbdata;
  88
  89         memset(&cbdata, 0, sizeof(cbdata));
  90         cbdata.flags = flags;
  91
  92         fd = hold_lock_file_for_update(&packed, git_path("packed-refs"),
  93                                        LOCK_DIE_ON_ERROR);
  94         cbdata.refs_file = fdopen(fd, "w");
  95         if (!cbdata.refs_file)
  96                 die("unable to create ref-pack file structure (%s)",
  97                     strerror(errno));
  98
  99         /* perhaps other traits later as well */
 100         fprintf(cbdata.refs_file, "# pack-refs with: peeled \n");
 101
 102         for_each_ref(handle_one_ref, &cbdata);
 103         if (ferror(cbdata.refs_file))
 104                 die("failed to write ref-pack file");
 105         if (fflush(cbdata.refs_file) || fsync(fd) || fclose(cbdata.refs_file))
 106                 die("failed to write ref-pack file (%s)", strerror(errno));
 107         /*
 108          * Since the lock file was fdopen()'ed and then fclose()'ed above,
 109          * assign -1 to the lock file descriptor so that commit_lock_file()
 110          * won't try to close() it.
 111          */
 112         packed.fd = -1;
 113         if (commit_lock_file(&packed) < 0)
 114                 die("unable to overwrite old ref-pack file (%s)", strerror(errno));
 115         if (cbdata.flags & PACK_REFS_PRUNE)
 116                 prune_refs(cbdata.ref_to_prune);
 117         return 0;
 118 }