replace-object.c

   1 #include "git-compat-util.h"
   2 #include "gettext.h"
   3 #include "hex.h"
   4 #include "oidmap.h"
   5 #include "object-store-ll.h"
   6 #include "replace-object.h"
   7 #include "refs.h"
   8 #include "repository.h"
   9 #include "commit.h"
  10
  11 static int register_replace_ref(const char *refname,
  12                                 const struct object_id *oid,
  13                                 int flag UNUSED,
  14                                 void *cb_data)
  15 {
  16         struct repository *r = cb_data;
  17
  18         /* Get sha1 from refname */
  19         const char *slash = strrchr(refname, '/');
  20         const char *hash = slash ? slash + 1 : refname;
  21         struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  22
  23         if (get_oid_hex_algop(hash, &repl_obj->original.oid, r->hash_algo)) {
  24                 free(repl_obj);
  25                 warning(_("bad replace ref name: %s"), refname);
  26                 return 0;
  27         }
  28
  29         /* Copy sha1 from the read ref */
  30         oidcpy(&repl_obj->replacement, oid);
  31
  32         /* Register new object */
  33         if (oidmap_put(r->objects->replace_map, repl_obj))
  34                 die(_("duplicate replace ref: %s"), refname);
  35
  36         return 0;
  37 }
  38
  39 void prepare_replace_object(struct repository *r)
  40 {
  41         if (r->objects->replace_map_initialized)
  42                 return;
  43
  44         pthread_mutex_lock(&r->objects->replace_mutex);
  45         if (r->objects->replace_map_initialized) {
  46                 pthread_mutex_unlock(&r->objects->replace_mutex);
  47                 return;
  48         }
  49
  50         r->objects->replace_map =
  51                 xmalloc(sizeof(*r->objects->replace_map));
  52         oidmap_init(r->objects->replace_map, 0);
  53
  54         refs_for_each_replace_ref(get_main_ref_store(r),
  55                                   register_replace_ref, r);
  56         r->objects->replace_map_initialized = 1;
  57
  58         pthread_mutex_unlock(&r->objects->replace_mutex);
  59 }
  60
  61 /* We allow "recursive" replacement. Only within reason, though */
  62 #define MAXREPLACEDEPTH 5
  63
  64 /*
  65  * If a replacement for object oid has been set up, return the
  66  * replacement object's name (replaced recursively, if necessary).
  67  * The return value is either oid or a pointer to a
  68  * permanently-allocated value.  This function always respects replace
  69  * references, regardless of the value of r->settings.read_replace_refs.
  70  */
  71 const struct object_id *do_lookup_replace_object(struct repository *r,
  72                                                  const struct object_id *oid)
  73 {
  74         int depth = MAXREPLACEDEPTH;
  75         const struct object_id *cur = oid;
  76
  77         prepare_replace_object(r);
  78
  79         /* Try to recursively replace the object */
  80         while (depth-- > 0) {
  81                 struct replace_object *repl_obj =
  82                         oidmap_get(r->objects->replace_map, cur);
  83                 if (!repl_obj)
  84                         return cur;
  85                 cur = &repl_obj->replacement;
  86         }
  87         die(_("replace depth too high for object %s"), oid_to_hex(oid));
  88 }
  89
  90 /*
  91  * This indicator determines whether replace references should be
  92  * respected process-wide, regardless of which repository is being
  93  * using at the time.
  94  */
  95 static int read_replace_refs = 1;
  96
  97 void disable_replace_refs(void)
  98 {
  99         read_replace_refs = 0;
 100 }
 101
 102 int replace_refs_enabled(struct repository *r)
 103 {
 104         if (!read_replace_refs)
 105                 return 0;
 106
 107         if (r->gitdir) {
 108                 prepare_repo_settings(r);
 109                 return r->settings.read_replace_refs;
 110         }
 111
 112         /* repository has no objects or refs. */
 113         return 0;
 114 }