pull: new option --commit-metadata-only

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

src/libostree/ostree-repo-pull.c

@@ -88,6 +88,7 @@ typedef struct {
   guint64           start_time;
 
   gboolean          is_mirror;
+  gboolean          is_commit_only;
 
   char         *dir;
   gboolean      commitpartial_exists;
@@ -1119,6 +1120,11 @@ scan_one_metadata_object_c (OtPullData         *pull_data,
       do_fetch_detached = (objtype == OSTREE_OBJECT_TYPE_COMMIT);
       enqueue_one_object_request (pull_data, tmp_checksum, objtype, do_fetch_detached, FALSE);
     }
+  else if (objtype == OSTREE_OBJECT_TYPE_COMMIT && pull_data->is_commit_only)
+    {
+      ret = TRUE;
+      goto out;
+    }
   else if (is_stored)
     {
       gboolean do_scan = pull_data->transaction_resuming || is_requested || pull_data->commitpartial_exists;
@@ -1654,6 +1660,7 @@ ostree_repo_pull_with_options (OstreeRepo             *self,
     g_return_val_if_fail (dir_to_pull[0] == '/', FALSE);
 
   pull_data->is_mirror = (flags & OSTREE_REPO_PULL_FLAGS_MIRROR) > 0;
+  pull_data->is_commit_only = (flags & OSTREE_REPO_PULL_FLAGS_COMMIT_ONLY) > 0;
 
   pull_data->async_error = error;
   pull_data->main_context = g_main_context_ref_thread_default ();
@@ -2160,7 +2167,7 @@ ostree_repo_pull_with_options (OstreeRepo             *self,
     }
 
   /* iterate over commits fetched and delete any commitpartial files */
-  if (!dir_to_pull)
+  if (!dir_to_pull && !pull_data->is_commit_only)
     {
       g_hash_table_iter_init (&hash_iter, requested_refs_to_fetch);
       while (g_hash_table_iter_next (&hash_iter, &key, &value))

src/libostree/ostree-repo.c

@@ -3674,6 +3674,9 @@ ostree_repo_read_commit (OstreeRepo   *self,
  * the @refs_to_fetch is %NULL, and the remote repository contains a
  * summary file, then all refs will be fetched.
  *
+ * If @flags contains %OSTREE_REPO_PULL_FLAGS_COMMIT_ONLY, then only the
+ * metadata for the commits in @refs_to_fetch is pulled.
+ *
  * Warning: This API will iterate the thread default main context,
  * which is a bug, but kept for compatibility reasons.  If you want to
  * avoid this, use g_main_context_push_thread_default() to push a new

src/libostree/ostree-repo.h

@@ -693,10 +693,12 @@ gboolean ostree_repo_prune (OstreeRepo        *self,
  * OstreeRepoPullFlags:
  * @OSTREE_REPO_PULL_FLAGS_NONE: No special options for pull
  * @OSTREE_REPO_PULL_FLAGS_MIRROR: Write out refs suitable for mirrors
+ * @OSTREE_REPO_PULL_FLAGS_COMMIT_ONLY: Fetch only the commit metadata
  */
 typedef enum {
   OSTREE_REPO_PULL_FLAGS_NONE,
-  OSTREE_REPO_PULL_FLAGS_MIRROR
+  OSTREE_REPO_PULL_FLAGS_MIRROR = (1 << 0),
+  OSTREE_REPO_PULL_FLAGS_COMMIT_ONLY = (1 << 1)
 } OstreeRepoPullFlags;
 
 gboolean ostree_repo_pull (OstreeRepo             *self,