core: Add --tar-autocreate-parents option for commit

The tar files we're making of artifacts don't include parent
directories.  Now we could change the builder to make them, but we can
also just autocreate them on import.  Mode 0755 with no xattrs seems
OK here.

src/libostree/ostree-repo.c

@@ -1585,6 +1585,7 @@ ostree_repo_stage_mtree (OstreeRepo           *self,
       while (g_hash_table_iter_next (&hash_iter, &key, &value))
         {
           const char *name = key;
+          const char *metadata_checksum;
           OstreeMutableTree *child_dir = value;
           char *child_dir_contents_checksum;
 
@@ -1592,10 +1593,13 @@ ostree_repo_stage_mtree (OstreeRepo           *self,
                                         cancellable, error))
             goto out;
       
+          g_assert (child_dir_contents_checksum);
           g_hash_table_replace (dir_contents_checksums, g_strdup (name),
                                 child_dir_contents_checksum); /* Transfer ownership */
+          metadata_checksum = ostree_mutable_tree_get_metadata_checksum (child_dir);
+          g_assert (metadata_checksum);
           g_hash_table_replace (dir_metadata_checksums, g_strdup (name),
-                                g_strdup (ostree_mutable_tree_get_metadata_checksum (child_dir)));
+                                g_strdup (metadata_checksum));
         }
     
       serialized_tree = create_tree_variant_from_hashes (ostree_mutable_tree_get_files (mtree),
@@ -1709,6 +1713,7 @@ stage_libarchive_entry_to_mtree (OstreeRepo           *self,
                                  struct archive       *a,
                                  struct archive_entry *entry,
                                  OstreeRepoCommitModifier *modifier,
+                                 const char               *tmp_dir_checksum,
                                  GCancellable         *cancellable,
                                  GError              **error)
 {
@@ -1738,8 +1743,19 @@ stage_libarchive_entry_to_mtree (OstreeRepo           *self,
     }
   else
     {
-      if (!ostree_mutable_tree_walk (root, split_path, 0, &parent, error))
-        goto out;
+      if (tmp_dir_checksum)
+        {
+          if (!ostree_mutable_tree_ensure_parent_dirs (root, split_path,
+                                                       tmp_dir_checksum,
+                                                       &parent,
+                                                       error))
+            goto out;
+        }
+      else
+        {
+          if (!ostree_mutable_tree_walk (root, split_path, 0, &parent, error))
+            goto out;
+        }
       basename = (char*)split_path->pdata[split_path->len-1];
     }
 
@@ -1854,18 +1870,21 @@ stage_libarchive_entry_to_mtree (OstreeRepo           *self,
 #endif
                           
 gboolean
-ostree_repo_stage_archive_to_mtree (OstreeRepo           *self,
-                                    GFile                *archive_f,
-                                    OstreeMutableTree    *root,
-                                    OstreeRepoCommitModifier *modifier,
-                                    GCancellable         *cancellable,
-                                    GError              **error)
+ostree_repo_stage_archive_to_mtree (OstreeRepo                *self,
+                                    GFile                     *archive_f,
+                                    OstreeMutableTree         *root,
+                                    OstreeRepoCommitModifier  *modifier,
+                                    gboolean                   autocreate_parents,
+                                    GCancellable             *cancellable,
+                                    GError                  **error)
 {
 #ifdef HAVE_LIBARCHIVE
   gboolean ret = FALSE;
-  struct archive *a;
+  struct archive *a = NULL;
   struct archive_entry *entry;
   int r;
+  GFileInfo *tmp_dir_info = NULL;
+  GChecksum *tmp_dir_checksum = NULL;
 
   a = archive_read_new ();
   archive_read_support_compression_all (a);
@@ -1887,7 +1906,22 @@ ostree_repo_stage_archive_to_mtree (OstreeRepo           *self,
           goto out;
         }
 
-      if (!stage_libarchive_entry_to_mtree (self, root, a, entry, modifier, cancellable, error))
+      if (autocreate_parents && !tmp_dir_checksum)
+        {
+          tmp_dir_info = g_file_info_new ();
+          
+          g_file_info_set_attribute_uint32 (tmp_dir_info, "unix::uid", archive_entry_uid (entry));
+          g_file_info_set_attribute_uint32 (tmp_dir_info, "unix::gid", archive_entry_gid (entry));
+          g_file_info_set_attribute_uint32 (tmp_dir_info, "unix::mode", 0755 | S_IFDIR);
+          
+          if (!stage_directory_meta (self, tmp_dir_info, NULL, &tmp_dir_checksum, cancellable, error))
+            goto out;
+        }
+
+      if (!stage_libarchive_entry_to_mtree (self, root, a,
+                                            entry, modifier,
+                                            autocreate_parents ? g_checksum_get_string (tmp_dir_checksum) : NULL,
+                                            cancellable, error))
         goto out;
     }
   if (archive_read_close (a) != ARCHIVE_OK)
@@ -1898,7 +1932,10 @@ ostree_repo_stage_archive_to_mtree (OstreeRepo           *self,
 
   ret = TRUE;
  out:
-  (void)archive_read_close (a);
+  g_clear_object (&tmp_dir_info);
+  ot_clear_checksum (&tmp_dir_checksum);
+  if (a)
+    (void)archive_read_close (a);
   return ret;
 #else
   g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,