LevelDB storage for data reduction proxy to store data usage stats.

components/data_reduction_proxy/core/browser/data_reduction_proxy_store.h

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_store.h
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_store.h b/components/data_reduction_proxy/core/browser/data_reduction_proxy_store.h
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+// 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 COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_STORE_H_
+#define COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_STORE_H_
+
+#include <map>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+
+namespace data_reduction_proxy {
+
+// Interface for a permanent key/value store used by the Data Reduction Proxy
+// component. This class has no-op methods for clients that do not want to
+// support a permanent store. |DataReductionProxyStoreImpl| provides a LevelDB
+// implementation.
+class DataReductionProxyStore
+    : public base::RefCountedThreadSafe<DataReductionProxyStore> {
+ public:
+  // Values are used in UMA. Do not change existing values; only append to the
+  // end. STATUS_MAX should always be last element.
+  enum Status { OK, NOT_FOUND, CORRUPTED, IO_ERROR, MISC_ERROR, STATUS_MAX };
+
+  DataReductionProxyStore();
+
+  // Initializes the store on DB Thread.
+  virtual void InitializeOnDBThread();
+
+  // Gets the value from the store for the provided key.
+  virtual Status Get(const std::string& key, std::string* value);
+
+  // Persists the provided keys and values into the store.
+  virtual Status Put(const std::map<std::string, std::string>& map);
+
+ protected:
+  virtual ~DataReductionProxyStore();
+
+ private:
+  // Ref counted classes have private destructors to prevent accidental deletion
+  // of the object when there are still references to it.
+  friend class base::RefCountedThreadSafe<DataReductionProxyStore>;
+
+  DISALLOW_COPY_AND_ASSIGN(DataReductionProxyStore);
+};
+
+}  // namespace data_reduction_proxy
+
+#endif  // COMPONENTS_DATA_REDUCTION_PROXY_CORE_BROWSER_DATA_REDUCTION_PROXY_STORE_H_