replace-object.c

   1 #include "cache.h"
   2 #include "oidmap.h"
   3 #include "object-store.h"
   4 #include "replace-object.h"
   5 #include "refs.h"
   6 #include "repository.h"
   7 #include "commit.h"
   8
   9 static int register_replace_ref(struct repository *r,
  10                                 const char *refname,
  11                                 const struct object_id *oid,
  12                                 int flag, void *cb_data)
  13 {
  14         /* Get sha1 from refname */
  15         const char *slash = strrchr(refname, '/');
  16         const char *hash = slash ? slash + 1 : refname;
  17         struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  18
  19         if (get_oid_hex(hash, &repl_obj->original.oid)) {
  20                 free(repl_obj);
  21                 warning(_("bad replace ref name: %s"), refname);
  22                 return 0;
  23         }
  24
  25         /* Copy sha1 from the read ref */
  26         oidcpy(&repl_obj->replacement, oid);
  27
  28         /* Register new object */
  29         if (oidmap_put(r->objects->replace_map, repl_obj))
  30                 die(_("duplicate replace ref: %s"), refname);
  31
  32         return 0;
  33 }
  34
  35 void prepare_replace_object(struct repository *r)
  36 {
  37         if (r->objects->replace_map_initialized)
  38                 return;
  39
  40         pthread_mutex_lock(&r->objects->replace_mutex);
  41         if (r->objects->replace_map_initialized) {
  42                 pthread_mutex_unlock(&r->objects->replace_mutex);
  43                 return;
  44         }
  45
  46         r->objects->replace_map =
  47                 xmalloc(sizeof(*r->objects->replace_map));
  48         oidmap_init(r->objects->replace_map, 0);
  49
  50         for_each_replace_ref(r, register_replace_ref, NULL);
  51         r->objects->replace_map_initialized = 1;
  52
  53         pthread_mutex_unlock(&r->objects->replace_mutex);
  54 }
  55
  56 /* We allow "recursive" replacement. Only within reason, though */
  57 #define MAXREPLACEDEPTH 5
  58
  59 /*
  60  * If a replacement for object oid has been set up, return the
  61  * replacement object's name (replaced recursively, if necessary).
  62  * The return value is either oid or a pointer to a
  63  * permanently-allocated value.  This function always respects replace
  64  * references, regardless of the value of read_replace_refs.
  65  */
  66 const struct object_id *do_lookup_replace_object(struct repository *r,
  67                                                  const struct object_id *oid)
  68 {
  69         int depth = MAXREPLACEDEPTH;
  70         const struct object_id *cur = oid;
  71
  72         prepare_replace_object(r);
  73
  74         /* Try to recursively replace the object */
  75         while (depth-- > 0) {
  76                 struct replace_object *repl_obj =
  77                         oidmap_get(r->objects->replace_map, cur);
  78                 if (!repl_obj)
  79                         return cur;
  80                 cur = &repl_obj->replacement;
  81         }
  82         die(_("replace depth too high for object %s"), oid_to_hex(oid));
  83 }