Implement XzExtentWriter.
The new XzExtentWriter class is an ExtentWriter that uses xz-embedded
to decompress an xz stream and write it to the underlying extent
writer. This will be used to implement REPLACE_XZ in a follow up CL.
Bug: 23604708
Test: Added unittests.
Change-Id: Ifd2ba0c917b66ab33e5cff1d6069da833ad54882
diff --git a/fake_extent_writer.h b/fake_extent_writer.h
new file mode 100644
index 0000000..a876893
--- /dev/null
+++ b/fake_extent_writer.h
@@ -0,0 +1,71 @@
+//
+// Copyright (C) 2015 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_FAKE_EXTENT_WRITER_H_
+#define UPDATE_ENGINE_FAKE_EXTENT_WRITER_H_
+
+#include <memory>
+#include <vector>
+
+#include <chromeos/secure_blob.h>
+
+#include "update_engine/extent_writer.h"
+
+namespace chromeos_update_engine {
+
+// FakeExtentWriter is a concrete ExtentWriter subclass that keeps track of all
+// the written data, useful for testing.
+class FakeExtentWriter : public ExtentWriter {
+ public:
+ FakeExtentWriter() = default;
+ ~FakeExtentWriter() override = default;
+
+ // ExtentWriter overrides.
+ bool Init(FileDescriptorPtr /* fd */,
+ const std::vector<Extent>& /* extents */,
+ uint32_t /* block_size */) override {
+ init_called_ = true;
+ return true;
+ };
+ bool Write(const void* bytes, size_t count) override {
+ if (!init_called_ || end_called_)
+ return false;
+ written_data_.insert(written_data_.end(),
+ reinterpret_cast<const uint8_t*>(bytes),
+ reinterpret_cast<const uint8_t*>(bytes) + count);
+ return true;
+ }
+ bool EndImpl() override {
+ end_called_ = true;
+ return true;
+ }
+
+ // Fake methods.
+ bool InitCalled() { return init_called_; }
+ bool EndCalled() { return end_called_; }
+ chromeos::Blob WrittenData() { return written_data_; }
+
+ private:
+ bool init_called_{false};
+ bool end_called_{false};
+ chromeos::Blob written_data_;
+
+ DISALLOW_COPY_AND_ASSIGN(FakeExtentWriter);
+};
+
+} // namespace chromeos_update_engine
+
+#endif // UPDATE_ENGINE_FAKE_EXTENT_WRITER_H_