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