xref: /external/chromium_org/components/data_reduction_proxy/browser/data_reduction_proxy_statistics_prefs.h

// Copyright 2014 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_BROWSER_DATA_REDUCTION_PROXY_STATISTICS_PREFS_H_
#define COMPONENTS_DATA_REDUCTION_PROXY_BROWSER_DATA_REDUCTION_PROXY_STATISTICS_PREFS_H_

#include <map>

#include "base/containers/scoped_ptr_hash_map.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/time/time.h"
#include "components/data_reduction_proxy/common/data_reduction_proxy_pref_names.h"

class PrefService;

namespace base {
class ListValue;
class SequencedTaskRunner;
}

namespace data_reduction_proxy {

// Data reduction proxy delayed pref service reduces the number calls to pref
// service by storing prefs in memory and writing to the given PrefService after
// |delay| amount of time. If |delay| is zero, the delayed pref service writes
// directly to the PrefService and does not store the prefs in memory. All
// prefs must be stored and read on the UI thread.
class DataReductionProxyStatisticsPrefs {
public:
  // Constructs a data reduction proxy delayed pref service object using
  // |pref_service|. Writes prefs to |pref_service| after |delay|
  // and stores them in |pref_map_| and |list_pref_map| between writes.
  // If |delay| is zero, writes directly to the PrefService and does not store
  // in the maps.
  DataReductionProxyStatisticsPrefs(
      PrefService* pref_service,
      scoped_refptr<base::SequencedTaskRunner> task_runner,
      const base::TimeDelta& delay);
  ~DataReductionProxyStatisticsPrefs();

  // Loads all data_reduction_proxy::prefs into the |pref_map_| and
  // |list_pref_map_|.
  void Init();

  // Gets the int64 pref at |pref_path| from the |DataReductionProxyPrefMap|.
  int64 GetInt64(const char* pref_path);

  // Updates the pref value in the |DataReductionProxyPrefMap| map.
  // The pref is later written to |pref service_|.
  void SetInt64(const char* pref_path, int64 pref_value);

  // Gets the pref list at |pref_path| from the |DataReductionProxyPrefMap|.
  base::ListValue* GetList(const char* pref_path);

  // Writes the prefs stored in |DataReductionProxyPrefMap| and
  // |DataReductionProxyListPrefMap| to |pref_service|.
  void WritePrefs();

private:
  typedef std::map<const char*, int64> DataReductionProxyPrefMap;
  typedef base::ScopedPtrHashMap<const char*, base::ListValue>
      DataReductionProxyListPrefMap;

  // Gets the value of |pref| from the pref service and adds it to the
  // |pref_map|.
  void InitInt64Pref(const char* pref);

  // Gets the value of |pref| from the pref service and adds it to the
  // |list_pref_map|.
  void InitListPref(const char* pref);

  // Writes the stored prefs to |pref_service| and then posts another a delayed
  // task to write prefs again in |kMinutesBetweenWrites|.
  void DelayedWritePrefs();

  // Copies the values at each index of |from_list| to the same index in
  // |to_list|.
  void TransferList(const base::ListValue& from_list,
                    base::ListValue* to_list);

  // Gets an int64, stored as a string, in a ListPref at the specified
  // index.
  int64 GetListPrefInt64Value(const base::ListValue& list_update, size_t index);

  PrefService* pref_service_;
  scoped_refptr<base::SequencedTaskRunner> task_runner_;
  base::WeakPtrFactory<DataReductionProxyStatisticsPrefs> weak_factory_;
  const base::TimeDelta delay_;
  bool delayed_task_posted_;
  DataReductionProxyPrefMap pref_map_;
  DataReductionProxyListPrefMap list_pref_map_;

  DISALLOW_COPY_AND_ASSIGN(DataReductionProxyStatisticsPrefs);
};

}  // namespace data_reduction_proxy

#endif  // COMPONENTS_DATA_REDUCTION_PROXY_BROWSER_DATA_REDUCTION_PROXY_STATISTICS_PREFS_H_