Move base/prefs to components/prefs

base/prefs/json_pref_store.h

 // Copyright (c) 2012 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 BASE_PREFS_JSON_PREF_STORE_H_
-#define BASE_PREFS_JSON_PREF_STORE_H_
-
-#include <stdint.h>
-
-#include <set>
-#include <string>
-
-#include "base/callback_forward.h"
-#include "base/compiler_specific.h"
-#include "base/files/file_path.h"
-#include "base/files/important_file_writer.h"
-#include "base/gtest_prod_util.h"
-#include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
-#include "base/observer_list.h"
-#include "base/prefs/base_prefs_export.h"
-#include "base/prefs/persistent_pref_store.h"
-#include "base/threading/non_thread_safe.h"
-
-class PrefFilter;
-
-namespace base {
-class Clock;
-class DictionaryValue;
-class FilePath;
-class HistogramBase;
-class JsonPrefStoreLossyWriteTest;
-class SequencedTaskRunner;
-class SequencedWorkerPool;
-class Value;
-FORWARD_DECLARE_TEST(JsonPrefStoreTest, WriteCountHistogramTestBasic);
-FORWARD_DECLARE_TEST(JsonPrefStoreTest, WriteCountHistogramTestSinglePeriod);
-FORWARD_DECLARE_TEST(JsonPrefStoreTest, WriteCountHistogramTestMultiplePeriods);
-FORWARD_DECLARE_TEST(JsonPrefStoreTest, WriteCountHistogramTestPeriodWithGaps);
-}
-
-// A writable PrefStore implementation that is used for user preferences.
-class BASE_PREFS_EXPORT JsonPrefStore
-    : public PersistentPrefStore,
-      public base::ImportantFileWriter::DataSerializer,
-      public base::SupportsWeakPtr<JsonPrefStore>,
-      public base::NonThreadSafe {
- public:
-  struct ReadResult;
-
-  // Returns instance of SequencedTaskRunner which guarantees that file
-  // operations on the same file will be executed in sequenced order.
-  static scoped_refptr<base::SequencedTaskRunner> GetTaskRunnerForFile(
-      const base::FilePath& pref_filename,
-      base::SequencedWorkerPool* worker_pool);
-
-  // Same as the constructor below with no alternate filename.
-  JsonPrefStore(
-      const base::FilePath& pref_filename,
-      const scoped_refptr<base::SequencedTaskRunner>& sequenced_task_runner,
-      scoped_ptr<PrefFilter> pref_filter);
-
-  // |sequenced_task_runner| must be a shutdown-blocking task runner, ideally
-  // created by the GetTaskRunnerForFile() method above.
-  // |pref_filename| is the path to the file to read prefs from.
-  // |pref_alternate_filename| is the path to an alternate file which the
-  // desired prefs may have previously been written to. If |pref_filename|
-  // doesn't exist and |pref_alternate_filename| does, |pref_alternate_filename|
-  // will be moved to |pref_filename| before the read occurs.
-  JsonPrefStore(
-      const base::FilePath& pref_filename,
-      const base::FilePath& pref_alternate_filename,
-      const scoped_refptr<base::SequencedTaskRunner>& sequenced_task_runner,
-      scoped_ptr<PrefFilter> pref_filter);
-
-  // PrefStore overrides:
-  bool GetValue(const std::string& key,
-                const base::Value** result) const override;
-  void AddObserver(PrefStore::Observer* observer) override;
-  void RemoveObserver(PrefStore::Observer* observer) override;
-  bool HasObservers() const override;
-  bool IsInitializationComplete() const override;
-
-  // PersistentPrefStore overrides:
-  bool GetMutableValue(const std::string& key, base::Value** result) override;
-  void SetValue(const std::string& key,
-                scoped_ptr<base::Value> value,
-                uint32_t flags) override;
-  void SetValueSilently(const std::string& key,
-                        scoped_ptr<base::Value> value,
-                        uint32_t flags) override;
-  void RemoveValue(const std::string& key, uint32_t flags) override;
-  bool ReadOnly() const override;
-  PrefReadError GetReadError() const override;
-  // Note this method may be asynchronous if this instance has a |pref_filter_|
-  // in which case it will return PREF_READ_ERROR_ASYNCHRONOUS_TASK_INCOMPLETE.
-  // See details in pref_filter.h.
-  PrefReadError ReadPrefs() override;
-  void ReadPrefsAsync(ReadErrorDelegate* error_delegate) override;
-  void CommitPendingWrite() override;
-  void SchedulePendingLossyWrites() override;
-  void ReportValueChanged(const std::string& key, uint32_t flags) override;
-
-  // Just like RemoveValue(), but doesn't notify observers. Used when doing some
-  // cleanup that shouldn't otherwise alert observers.
-  void RemoveValueSilently(const std::string& key, uint32_t flags);
-
-  // Registers |on_next_successful_write| to be called once, on the next
-  // successful write event of |writer_|.
-  void RegisterOnNextSuccessfulWriteCallback(
-      const base::Closure& on_next_successful_write);
-
- private:
-  // Represents a histogram for recording the number of writes to the pref file
-  // that occur every kHistogramWriteReportIntervalInMins minutes.
-  class BASE_PREFS_EXPORT WriteCountHistogram {
-   public:
-    static const int32_t kHistogramWriteReportIntervalMins;
-
-    WriteCountHistogram(const base::TimeDelta& commit_interval,
-                        const base::FilePath& path);
-    // Constructor for testing. |clock| is a test Clock that is used to retrieve
-    // the time.
-    WriteCountHistogram(const base::TimeDelta& commit_interval,
-                        const base::FilePath& path,
-                        scoped_ptr<base::Clock> clock);
-    ~WriteCountHistogram();
-
-    // Record that a write has occured.
-    void RecordWriteOccured();
-
-    // Reports writes (that have not yet been reported) in all of the recorded
-    // intervals that have elapsed up until current time.
-    void ReportOutstandingWrites();
-
-    base::HistogramBase* GetHistogram();
-
-   private:
-    // The minimum interval at which writes can occur.
-    const base::TimeDelta commit_interval_;
-
-    // The path to the file.
-    const base::FilePath path_;
-
-    // Clock which is used to retrieve the current time.
-    scoped_ptr<base::Clock> clock_;
-
-    // The interval at which to report write counts.
-    const base::TimeDelta report_interval_;
-
-    // The time at which the last histogram value was reported for the number
-    // of write counts.
-    base::Time last_report_time_;
-
-    // The number of writes that have occured since the last write count was
-    // reported.
-    uint32_t writes_since_last_report_;
-
-    DISALLOW_COPY_AND_ASSIGN(WriteCountHistogram);
-  };
-
-  FRIEND_TEST_ALL_PREFIXES(base::JsonPrefStoreTest,
-                           WriteCountHistogramTestBasic);
-  FRIEND_TEST_ALL_PREFIXES(base::JsonPrefStoreTest,
-                           WriteCountHistogramTestSinglePeriod);
-  FRIEND_TEST_ALL_PREFIXES(base::JsonPrefStoreTest,
-                           WriteCountHistogramTestMultiplePeriods);
-  FRIEND_TEST_ALL_PREFIXES(base::JsonPrefStoreTest,
-                           WriteCountHistogramTestPeriodWithGaps);
-  friend class base::JsonPrefStoreLossyWriteTest;
-
-  ~JsonPrefStore() override;
-
-  // This method is called after the JSON file has been read.  It then hands
-  // |value| (or an empty dictionary in some read error cases) to the
-  // |pref_filter| if one is set. It also gives a callback pointing at
-  // FinalizeFileRead() to that |pref_filter_| which is then responsible for
-  // invoking it when done. If there is no |pref_filter_|, FinalizeFileRead()
-  // is invoked directly.
-  void OnFileRead(scoped_ptr<ReadResult> read_result);
-
-  // ImportantFileWriter::DataSerializer overrides:
-  bool SerializeData(std::string* output) override;
-
-  // This method is called after the JSON file has been read and the result has
-  // potentially been intercepted and modified by |pref_filter_|.
-  // |initialization_successful| is pre-determined by OnFileRead() and should
-  // be used when reporting OnInitializationCompleted().
-  // |schedule_write| indicates whether a write should be immediately scheduled
-  // (typically because the |pref_filter_| has already altered the |prefs|) --
-  // this will be ignored if this store is read-only.
-  void FinalizeFileRead(bool initialization_successful,
-                        scoped_ptr<base::DictionaryValue> prefs,
-                        bool schedule_write);
-
-  // Schedule a write with the file writer as long as |flags| doesn't contain
-  // WriteablePrefStore::LOSSY_PREF_WRITE_FLAG.
-  void ScheduleWrite(uint32_t flags);
-
-  const base::FilePath path_;
-  const base::FilePath alternate_path_;
-  const scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner_;
-
-  scoped_ptr<base::DictionaryValue> prefs_;
-
-  bool read_only_;
-
-  // Helper for safely writing pref data.
-  base::ImportantFileWriter writer_;
-
-  scoped_ptr<PrefFilter> pref_filter_;
-  base::ObserverList<PrefStore::Observer, true> observers_;
-
-  scoped_ptr<ReadErrorDelegate> error_delegate_;
-
-  bool initialized_;
-  bool filtering_in_progress_;
-  bool pending_lossy_write_;
-  PrefReadError read_error_;
-
-  std::set<std::string> keys_need_empty_value_;
-
-  WriteCountHistogram write_count_histogram_;
-
-  DISALLOW_COPY_AND_ASSIGN(JsonPrefStore);
-};
-
-#endif  // BASE_PREFS_JSON_PREF_STORE_H_
+// TODO(brettw) remove this forwarding header when prefs is completely moved to
+// components.
+#include "components/prefs/json_pref_store.h"