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 UNUSED,
  13                                 void *cb_data UNUSED)
  14 {
  15         /* Get sha1 from refname */
  16         const char *slash = strrchr(refname, '/');
  17         const char *hash = slash ? slash + 1 : refname;
  18         struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  19
  20         if (get_oid_hex(hash, &repl_obj->original.oid)) {
  21                 free(repl_obj);
  22                 warning(_("bad replace ref name: %s"), refname);
  23                 return 0;
  24         }
  25
  26         /* Copy sha1 from the read ref */
  27         oidcpy(&repl_obj->replacement, oid);
  28
  29         /* Register new object */
  30         if (oidmap_put(r->objects->replace_map, repl_obj))
  31                 die(_("duplicate replace ref: %s"), refname);
  32
  33         return 0;
  34 }
  35
  36 void prepare_replace_object(struct repository *r)
  37 {
  38         if (r->objects->replace_map_initialized)
  39                 return;
  40
  41         pthread_mutex_lock(&r->objects->replace_mutex);
  42         if (r->objects->replace_map_initialized) {
  43                 pthread_mutex_unlock(&r->objects->replace_mutex);
  44                 return;
  45         }
  46
  47         r->objects->replace_map =
  48                 xmalloc(sizeof(*r->objects->replace_map));
  49         oidmap_init(r->objects->replace_map, 0);
  50
  51         for_each_replace_ref(r, register_replace_ref, NULL);
  52         r->objects->replace_map_initialized = 1;
  53
  54         pthread_mutex_unlock(&r->objects->replace_mutex);
  55 }
  56
  57 /* We allow "recursive" replacement. Only within reason, though */
  58 #define MAXREPLACEDEPTH 5
  59
  60 /*
  61  * If a replacement for object oid has been set up, return the
  62  * replacement object's name (replaced recursively, if necessary).
  63  * The return value is either oid or a pointer to a
  64  * permanently-allocated value.  This function always respects replace
  65  * references, regardless of the value of read_replace_refs.
  66  */
  67 const struct object_id *do_lookup_replace_object(struct repository *r,
  68                                                  const struct object_id *oid)
  69 {
  70         int depth = MAXREPLACEDEPTH;
  71         const struct object_id *cur = oid;
  72
  73         prepare_replace_object(r);
  74
  75         /* Try to recursively replace the object */
  76         while (depth-- > 0) {
  77                 struct replace_object *repl_obj =
  78                         oidmap_get(r->objects->replace_map, cur);
  79                 if (!repl_obj)
  80                         return cur;
  81                 cur = &repl_obj->replacement;
  82         }
  83         die(_("replace depth too high for object %s"), oid_to_hex(oid));
  84 }