replace-object.c

   1 #include "cache.h"
   2 #include "hex.h"
   3 #include "oidmap.h"
   4 #include "object-store.h"
   5 #include "replace-object.h"
   6 #include "refs.h"
   7 #include "repository.h"
   8 #include "commit.h"
   9
  10 static int register_replace_ref(struct repository *r,
  11                                 const char *refname,
  12                                 const struct object_id *oid,
  13                                 int flag UNUSED,
  14                                 void *cb_data UNUSED)
  15 {
  16         /* Get sha1 from refname */
  17         const char *slash = strrchr(refname, '/');
  18         const char *hash = slash ? slash + 1 : refname;
  19         struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  20
  21         if (get_oid_hex(hash, &repl_obj->original.oid)) {
  22                 free(repl_obj);
  23                 warning(_("bad replace ref name: %s"), refname);
  24                 return 0;
  25         }
  26
  27         /* Copy sha1 from the read ref */
  28         oidcpy(&repl_obj->replacement, oid);
  29
  30         /* Register new object */
  31         if (oidmap_put(r->objects->replace_map, repl_obj))
  32                 die(_("duplicate replace ref: %s"), refname);
  33
  34         return 0;
  35 }
  36
  37 void prepare_replace_object(struct repository *r)
  38 {
  39         if (r->objects->replace_map_initialized)
  40                 return;
  41
  42         pthread_mutex_lock(&r->objects->replace_mutex);
  43         if (r->objects->replace_map_initialized) {
  44                 pthread_mutex_unlock(&r->objects->replace_mutex);
  45                 return;
  46         }
  47
  48         r->objects->replace_map =
  49                 xmalloc(sizeof(*r->objects->replace_map));
  50         oidmap_init(r->objects->replace_map, 0);
  51
  52         for_each_replace_ref(r, register_replace_ref, NULL);
  53         r->objects->replace_map_initialized = 1;
  54
  55         pthread_mutex_unlock(&r->objects->replace_mutex);
  56 }
  57
  58 /* We allow "recursive" replacement. Only within reason, though */
  59 #define MAXREPLACEDEPTH 5
  60
  61 /*
  62  * If a replacement for object oid has been set up, return the
  63  * replacement object's name (replaced recursively, if necessary).
  64  * The return value is either oid or a pointer to a
  65  * permanently-allocated value.  This function always respects replace
  66  * references, regardless of the value of read_replace_refs.
  67  */
  68 const struct object_id *do_lookup_replace_object(struct repository *r,
  69                                                  const struct object_id *oid)
  70 {
  71         int depth = MAXREPLACEDEPTH;
  72         const struct object_id *cur = oid;
  73
  74         prepare_replace_object(r);
  75
  76         /* Try to recursively replace the object */
  77         while (depth-- > 0) {
  78                 struct replace_object *repl_obj =
  79                         oidmap_get(r->objects->replace_map, cur);
  80                 if (!repl_obj)
  81                         return cur;
  82                 cur = &repl_obj->replacement;
  83         }
  84         die(_("replace depth too high for object %s"), oid_to_hex(oid));
  85 }