[Sync] Add ModelTypeStore implementation.

sync/internal_api/public/model_type_store_impl.h

Index: sync/internal_api/public/model_type_store_impl.h
diff --git a/sync/internal_api/public/model_type_store_impl.h b/sync/internal_api/public/model_type_store_impl.h
new file mode 100644
index 0000000000000000000000000000000000000000..5ee4fab27d344c2ef1c8de6aa42d8cdca89326ba
--- /dev/null
+++ b/sync/internal_api/public/model_type_store_impl.h
@@ -0,0 +1,71 @@
+// Copyright 2015 The Chromium 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 SYNC_INTERNAL_API_PUBLIC_MODEL_TYPE_STORE_IMPL_H_
+#define SYNC_INTERNAL_API_PUBLIC_MODEL_TYPE_STORE_IMPL_H_
+
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/non_thread_safe.h"
+#include "sync/api/model_type_store.h"
+
+namespace syncer_v2 {
+
+class ModelTypeStoreBackend;
+
+// ModelTypeStoreImpl handles details of store initialization, threading and
+// leveldb key formatting. Actual leveldb IO calls are performed by
+// ModelTypeStoreBackend.
+class ModelTypeStoreImpl : public ModelTypeStore, public base::NonThreadSafe {
+ public:
+  ~ModelTypeStoreImpl() override;
+
+  static void CreateInMemoryStoreForTest(const InitCallback& callback);
+
+  // ModelTypeStore implementation.
+  void ReadData(const IdList& id_list,
+                const ReadRecordsCallback& callback) override;
+  void ReadAllData(const ReadRecordsCallback& callback) override;
+  void ReadAllMetadata(const ReadMetadataCallback& callback) override;
+  scoped_ptr<WriteBatch> CreateWriteBatch() override;
+  void CommitWriteBatch(scoped_ptr<WriteBatch> write_batch,
+                        const CallbackWithResult& callback) override;
+  void WriteData(WriteBatch* write_batch,
+                 const std::string& id,
+                 const std::string& value) override;
+  void WriteMetadata(WriteBatch* write_batch,
+                     const std::string& id,
+                     const std::string& value) override;
+  void WriteGlobalMetadata(WriteBatch* write_batch,
+                           const std::string& value) override;
+  void DeleteData(WriteBatch* write_batch, const std::string& id) override;
+  void DeleteMetadata(WriteBatch* write_batch, const std::string& id) override;
+  void DeleteGlobalMetadata(WriteBatch* write_batch) override;
+
+ private:
+  class WriteBatchImpl : public ModelTypeStore::WriteBatch {
+   public:

[stanisc, 2015/11/03 18:52:20]

Is this necessary?

[pavely, 2015/11/03 21:38:08]

I've created empty class as placeholder. It will own lebeldb's WriteBatch in the
next change.

+  };
+
+  static void BackendInitDone(const InitCallback& callback,
+                              scoped_ptr<ModelTypeStoreImpl> store,
+                              Result result);
+
+  ModelTypeStoreImpl(
+      scoped_ptr<ModelTypeStoreBackend> backend,
+      scoped_refptr<base::SingleThreadTaskRunner> backend_task_runner);
+
+  // Backend is owned by store, but should be deleted on backend thread. To
+  // accomplish this store's dtor posts task to backend thread passing backend
+  // ownership to task parameter.
+  scoped_ptr<ModelTypeStoreBackend> backend_;
+  scoped_refptr<base::SingleThreadTaskRunner> backend_task_runner_;
+};
+
+}  // namespace syncer_v2
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_MODEL_TYPE_STORE_IMPL_H_