Move extent copy and hash logic to a new file.

The SOURCE_COPY operation used to copy the source blocks one by one to
the target partition. This process is sub-optimal if there are several
consecutive blocks. This patch moves this copy and hash logic to a new
file and adds several unittests for it. The new logic copies in chunks
of up to 1MiB when the source and target data is contiguous.

BUG=b:34284069
TEST=Added unittests.

Change-Id: I9ed52b429a54a2b4d6edaba051284b7dcd8a9525
(cherry picked from commit a48f630400429ca010c5462967607985f2ffa7e4)
Reviewed-on: https://chromium-review.googlesource.com/641958
Commit-Ready: Amin Hassani <ahassani@chromium.org>
Tested-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Sen Jiang <senj@chromium.org>

1 files changed, 50 insertions, 0 deletions

diff --git a/payload_consumer/file_descriptor_utils.h b/payload_consumer/file_descriptor_utils.h
new file mode 100644
index 00000000..b73defbd
--- /dev/null
+++ b/payload_consumer/file_descriptor_utils.h
@@ -0,0 +1,50 @@
+//
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_FILE_DESCRIPTOR_UTILS_H_
+#define UPDATE_ENGINE_PAYLOAD_CONSUMER_FILE_DESCRIPTOR_UTILS_H_
+
+#include <vector>
+
+#include <brillo/secure_blob.h>
+
+#include "update_engine/payload_consumer/file_descriptor.h"
+#include "update_engine/update_metadata.pb.h"
+
+namespace chromeos_update_engine {
+namespace fd_utils {
+
+// Copy a blocks from the |source| file to the |target| file and hash the
+// contents. The blocks to copy from the |source| to the |target| files are
+// specified by the |src_extents| and |tgt_extents| list of Extents, which
+// must have the same length in number of blocks. Stores the hash of the
+// copied blocks in Blob pointed by |hash_out| if not null. The block size
+// is passed as |block_size|. In case of error reading or writing, returns
+// false and the value pointed by |hash_out| is undefined.
+// The |source| and |target| files must be different, or otherwise |src_extents|
+// and |tgt_extents| must not overlap.
+bool CopyAndHashExtents(
+    FileDescriptorPtr source,
+    const google::protobuf::RepeatedPtrField<Extent>& src_extents,
+    FileDescriptorPtr target,
+    const google::protobuf::RepeatedPtrField<Extent>& tgt_extents,
+    uint32_t block_size,
+    brillo::Blob* hash_out);
+
+}  // namespace fd_utils
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_FILE_DESCRIPTOR_UTILS_H_