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 /*
  64  * Remove empty parents, but spare refs/ and immediate subdirs.
  65  * Note: munges *name.
  66  */
  67 static void try_remove_empty_parents(char *name)
  68 {
  69         char *p, *q;
  70         int i;
  71         p = name;
  72         for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
  73                 while (*p && *p != '/')
  74                         p++;
  75                 /* tolerate duplicate slashes; see check_ref_format() */
  76                 while (*p == '/')
  77                         p++;
  78         }
  79         for (q = p; *q; q++)
  80                 ;
  81         while (1) {
  82                 while (q > p && *q != '/')
  83                         q--;
  84                 while (q > p && *(q-1) == '/')
  85                         q--;
  86                 if (q == p)
  87                         break;
  88                 *q = '\0';
  89                 if (rmdir(git_path("%s", name)))
  90                         break;
  91         }
  92 }
  93
  94 /* make sure nobody touched the ref, and unlink */
  95 static void prune_ref(struct ref_to_prune *r)
  96 {
  97         struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
  98
  99         if (lock) {
 100                 unlink_or_warn(git_path("%s", r->name));
 101                 unlock_ref(lock);
 102                 try_remove_empty_parents(r->name);
 103         }
 104 }
 105
 106 static void prune_refs(struct ref_to_prune *r)
 107 {
 108         while (r) {
 109                 prune_ref(r);
 110                 r = r->next;
 111         }
 112 }
 113
 114 static struct lock_file packed;
 115
 116 int pack_refs(unsigned int flags)
 117 {
 118         int fd;
 119         struct pack_refs_cb_data cbdata;
 120
 121         memset(&cbdata, 0, sizeof(cbdata));
 122         cbdata.flags = flags;
 123
 124         fd = hold_lock_file_for_update(&packed, git_path("packed-refs"),
 125                                        LOCK_DIE_ON_ERROR);
 126         cbdata.refs_file = fdopen(fd, "w");
 127         if (!cbdata.refs_file)
 128                 die_errno("unable to create ref-pack file structure");
 129
 130         /* perhaps other traits later as well */
 131         fprintf(cbdata.refs_file, "# pack-refs with: peeled \n");
 132
 133         for_each_ref(handle_one_ref, &cbdata);
 134         if (ferror(cbdata.refs_file))
 135                 die("failed to write ref-pack file");
 136         if (fflush(cbdata.refs_file) || fsync(fd) || fclose(cbdata.refs_file))
 137                 die_errno("failed to write ref-pack file");
 138         /*
 139          * Since the lock file was fdopen()'ed and then fclose()'ed above,
 140          * assign -1 to the lock file descriptor so that commit_lock_file()
 141          * won't try to close() it.
 142          */
 143         packed.fd = -1;
 144         if (commit_lock_file(&packed) < 0)
 145                 die_errno("unable to overwrite old ref-pack file");
 146         if (cbdata.flags & PACK_REFS_PRUNE)
 147                 prune_refs(cbdata.ref_to_prune);
 148         return 0;
 149 }