64 lines
2.2 KiB
C
64 lines
2.2 KiB
C
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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_PREFS_PREF_STORE_H_
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#define BASE_PREFS_PREF_STORE_H_
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#include <string>
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#include "base/basictypes.h"
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#include "base/memory/ref_counted.h"
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#include "base/prefs/base_prefs_export.h"
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namespace base {
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class Value;
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}
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// This is an abstract interface for reading and writing from/to a persistent
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// preference store, used by PrefService. An implementation using a JSON file
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// can be found in JsonPrefStore, while an implementation without any backing
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// store for testing can be found in TestingPrefStore. Furthermore, there is
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// CommandLinePrefStore, which bridges command line options to preferences and
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// ConfigurationPolicyPrefStore, which is used for hooking up configuration
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// policy with the preference subsystem.
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class BASE_PREFS_EXPORT PrefStore : public base::RefCounted<PrefStore> {
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public:
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// Observer interface for monitoring PrefStore.
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class BASE_PREFS_EXPORT Observer {
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public:
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// Called when the value for the given |key| in the store changes.
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virtual void OnPrefValueChanged(const std::string& key) = 0;
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// Notification about the PrefStore being fully initialized.
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virtual void OnInitializationCompleted(bool succeeded) = 0;
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protected:
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virtual ~Observer() {}
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};
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PrefStore() {}
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// Add and remove observers.
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virtual void AddObserver(Observer* observer) {}
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virtual void RemoveObserver(Observer* observer) {}
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virtual size_t NumberOfObservers() const;
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// Whether the store has completed all asynchronous initialization.
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virtual bool IsInitializationComplete() const;
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// Get the value for a given preference |key| and stores it in |*result|.
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// |*result| is only modified if the return value is true and if |result|
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// is not NULL. Ownership of the |*result| value remains with the PrefStore.
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virtual bool GetValue(const std::string& key,
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const base::Value** result) const = 0;
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protected:
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friend class base::RefCounted<PrefStore>;
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virtual ~PrefStore() {}
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private:
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DISALLOW_COPY_AND_ASSIGN(PrefStore);
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};
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#endif // BASE_PREFS_PREF_STORE_H_
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