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.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(struct repository *r,
  12                                 const char *refname,
  13                                 const struct object_id *oid,
  14                                 int flag UNUSED,
  15                                 void *cb_data UNUSED)
  16 {
  17         /* Get sha1 from refname */
  18         const char *slash = strrchr(refname, '/');
  19         const char *hash = slash ? slash + 1 : refname;
  20         struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  21
  22         if (get_oid_hex(hash, &repl_obj->original.oid)) {
  23                 free(repl_obj);
  24                 warning(_("bad replace ref name: %s"), refname);
  25                 return 0;
  26         }
  27
  28         /* Copy sha1 from the read ref */
  29         oidcpy(&repl_obj->replacement, oid);
  30
  31         /* Register new object */
  32         if (oidmap_put(r->objects->replace_map, repl_obj))
  33                 die(_("duplicate replace ref: %s"), refname);
  34
  35         return 0;
  36 }
  37
  38 void prepare_replace_object(struct repository *r)
  39 {
  40         if (r->objects->replace_map_initialized)
  41                 return;
  42
  43         pthread_mutex_lock(&r->objects->replace_mutex);
  44         if (r->objects->replace_map_initialized) {
  45                 pthread_mutex_unlock(&r->objects->replace_mutex);
  46                 return;
  47         }
  48
  49         r->objects->replace_map =
  50                 xmalloc(sizeof(*r->objects->replace_map));
  51         oidmap_init(r->objects->replace_map, 0);
  52
  53         for_each_replace_ref(r, register_replace_ref, NULL);
  54         r->objects->replace_map_initialized = 1;
  55
  56         pthread_mutex_unlock(&r->objects->replace_mutex);
  57 }
  58
  59 /* We allow "recursive" replacement. Only within reason, though */
  60 #define MAXREPLACEDEPTH 5
  61
  62 /*
  63  * If a replacement for object oid has been set up, return the
  64  * replacement object's name (replaced recursively, if necessary).
  65  * The return value is either oid or a pointer to a
  66  * permanently-allocated value.  This function always respects replace
  67  * references, regardless of the value of read_replace_refs.
  68  */
  69 const struct object_id *do_lookup_replace_object(struct repository *r,
  70                                                  const struct object_id *oid)
  71 {
  72         int depth = MAXREPLACEDEPTH;
  73         const struct object_id *cur = oid;
  74
  75         prepare_replace_object(r);
  76
  77         /* Try to recursively replace the object */
  78         while (depth-- > 0) {
  79                 struct replace_object *repl_obj =
  80                         oidmap_get(r->objects->replace_map, cur);
  81                 if (!repl_obj)
  82                         return cur;
  83                 cur = &repl_obj->replacement;
  84         }
  85         die(_("replace depth too high for object %s"), oid_to_hex(oid));
  86 }