update_engine: Change OperationsGenerator to use BlobFileWriter

BUG=chromium:517280
TEST=Unit test for BlobFileWriter

Change-Id: Ib49925676331acee97ff6b4cec38a81ca8b157a1
Reviewed-on: https://chromium-review.googlesource.com/291441
Tested-by: Sen Jiang <senj@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Sen Jiang <senj@chromium.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/payload_generator/blob_file_writer.h b/payload_generator/blob_file_writer.h
new file mode 100644
index 00000000..be8fd0db
--- /dev/null
+++ b/payload_generator/blob_file_writer.h
@@ -0,0 +1,46 @@
+// Copyright 2015 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UPDATE_ENGINE_PAYLOAD_GENERATOR_BLOB_FILE_WRITER_H_
+#define UPDATE_ENGINE_PAYLOAD_GENERATOR_BLOB_FILE_WRITER_H_
+
+#include <base/macros.h>
+
+#include <base/synchronization/lock.h>
+#include <chromeos/secure_blob.h>
+
+namespace chromeos_update_engine {
+
+class BlobFileWriter {
+ public:
+  // Create the BlobFileWriter object that will manage the blobs stored to
+  // |blob_fd| in a thread safe way.
+  BlobFileWriter(int blob_fd, off_t* blob_file_size)
+    : blob_fd_(blob_fd),
+      blob_file_size_(blob_file_size) {}
+
+  // Store the passed |blob| in the blob file. Returns the offset at which it
+  // was stored, or -1 in case of failure.
+  off_t StoreBlob(const chromeos::Blob& blob);
+
+  // The number of |total_blobs| is the number of blobs that will be stored but
+  // is only used for logging purposes. If not set, logging will be skipped.
+  void SetTotalBlobs(size_t total_blobs);
+
+ private:
+  size_t total_blobs_{0};
+  size_t stored_blobs_{0};
+
+  // The file and its size are protected with the |blob_mutex_|.
+  int blob_fd_;
+  off_t* blob_file_size_;
+
+  base::Lock blob_mutex_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobFileWriter);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_PAYLOAD_GENERATOR_BLOB_FILE_WRITER_H_