replace-object.c

   1 #include "git-compat-util.h"
   2 #include "gettext.h"
   3 #include "hex.h"
   4 #include "oidmap.h"
   5 #include "odb.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(const char *refname,
  12                                 const char *referent UNUSED,
  13                                 const struct object_id *oid,
  14                                 int flag UNUSED,
  15                                 void *cb_data)
  16 {
  17         struct repository *r = cb_data;
  18
  19         /* Get sha1 from refname */
  20         const char *slash = strrchr(refname, '/');
  21         const char *hash = slash ? slash + 1 : refname;
  22         struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  23
  24         if (get_oid_hex_algop(hash, &repl_obj->original.oid, r->hash_algo)) {
  25                 free(repl_obj);
  26                 warning(_("bad replace ref name: %s"), refname);
  27                 return 0;
  28         }
  29
  30         /* Copy sha1 from the read ref */
  31         oidcpy(&repl_obj->replacement, oid);
  32
  33         /* Register new object */
  34         if (oidmap_put(&r->objects->replace_map, repl_obj))
  35                 die(_("duplicate replace ref: %s"), refname);
  36
  37         return 0;
  38 }
  39
  40 void prepare_replace_object(struct repository *r)
  41 {
  42         if (r->objects->replace_map_initialized)
  43                 return;
  44
  45         pthread_mutex_lock(&r->objects->replace_mutex);
  46         if (r->objects->replace_map_initialized) {
  47                 pthread_mutex_unlock(&r->objects->replace_mutex);
  48                 return;
  49         }
  50
  51         oidmap_init(&r->objects->replace_map, 0);
  52
  53         refs_for_each_replace_ref(get_main_ref_store(r),
  54                                   register_replace_ref, r);
  55         r->objects->replace_map_initialized = 1;
  56
  57         pthread_mutex_unlock(&r->objects->replace_mutex);
  58 }
  59
  60 /* We allow "recursive" replacement. Only within reason, though */
  61 #define MAXREPLACEDEPTH 5
  62
  63 /*
  64  * If a replacement for object oid has been set up, return the
  65  * replacement object's name (replaced recursively, if necessary).
  66  * The return value is either oid or a pointer to a
  67  * permanently-allocated value.  This function always respects replace
  68  * references, regardless of the value of r->settings.read_replace_refs.
  69  */
  70 const struct object_id *do_lookup_replace_object(struct repository *r,
  71                                                  const struct object_id *oid)
  72 {
  73         int depth = MAXREPLACEDEPTH;
  74         const struct object_id *cur = oid;
  75
  76         prepare_replace_object(r);
  77
  78         /* Try to recursively replace the object */
  79         while (depth-- > 0) {
  80                 struct replace_object *repl_obj =
  81                         oidmap_get(&r->objects->replace_map, cur);
  82                 if (!repl_obj)
  83                         return cur;
  84                 cur = &repl_obj->replacement;
  85         }
  86         die(_("replace depth too high for object %s"), oid_to_hex(oid));
  87 }
  88
  89 /*
  90  * This indicator determines whether replace references should be
  91  * respected process-wide, regardless of which repository is being
  92  * using at the time.
  93  */
  94 static int read_replace_refs = 1;
  95
  96 void disable_replace_refs(void)
  97 {
  98         read_replace_refs = 0;
  99 }
 100
 101 int replace_refs_enabled(struct repository *r)
 102 {
 103         if (!read_replace_refs)
 104                 return 0;
 105
 106         if (r->gitdir) {
 107                 prepare_repo_settings(r);
 108                 return r->settings.read_replace_refs;
 109         }
 110
 111         /* repository has no objects or refs. */
 112         return 0;
 113 }