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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_PREFS_PERSISTENT_PREF_STORE_H_
#define COMPONENTS_PREFS_PERSISTENT_PREF_STORE_H_
#include "base/functional/callback.h"
#include "components/prefs/pref_filter.h"
#include "components/prefs/prefs_export.h"
#include "components/prefs/writeable_pref_store.h"
// This interface is complementary to the PrefStore interface, declaring
// additional functionality that adds support for setting values and persisting
// the data to some backing store.
class COMPONENTS_PREFS_EXPORT PersistentPrefStore : public WriteablePrefStore {
public:
// Unique integer code for each type of error so we can report them
// distinctly in a histogram.
// NOTE: Don't change the explicit values of the enums as it will change the
// server's meaning of the histogram.
enum PrefReadError {
PREF_READ_ERROR_NONE = 0,
PREF_READ_ERROR_JSON_PARSE = 1,
PREF_READ_ERROR_JSON_TYPE = 2,
PREF_READ_ERROR_ACCESS_DENIED = 3,
PREF_READ_ERROR_FILE_OTHER = 4,
PREF_READ_ERROR_FILE_LOCKED = 5,
PREF_READ_ERROR_NO_FILE = 6,
PREF_READ_ERROR_JSON_REPEAT = 7,
// PREF_READ_ERROR_OTHER = 8, // Deprecated.
PREF_READ_ERROR_FILE_NOT_SPECIFIED = 9,
// Indicates that ReadPrefs() couldn't complete synchronously and is waiting
// for an asynchronous task to complete first.
PREF_READ_ERROR_ASYNCHRONOUS_TASK_INCOMPLETE = 10,
PREF_READ_ERROR_MAX_ENUM
};
class ReadErrorDelegate {
public:
virtual ~ReadErrorDelegate() = default;
virtual void OnError(PrefReadError error) = 0;
};
// Whether the store is in a pseudo-read-only mode where changes are not
// actually persisted to disk. This happens in some cases when there are
// read errors during startup.
virtual bool ReadOnly() const = 0;
// Gets the read error. Only valid if IsInitializationComplete() returns true.
virtual PrefReadError GetReadError() const = 0;
// Reads the preferences from disk. Notifies observers via
// "PrefStore::OnInitializationCompleted" when done.
virtual PrefReadError ReadPrefs() = 0;
// Reads the preferences from disk asynchronously. Notifies observers via
// "PrefStore::OnInitializationCompleted" when done. Also it fires
// |error_delegate| if it is not NULL and reading error has occurred.
// Owns |error_delegate|.
virtual void ReadPrefsAsync(ReadErrorDelegate* error_delegate) = 0;
// Lands pending writes to disk. |reply_callback| will be posted to the
// current sequence when changes have been written.
// |synchronous_done_callback| on the other hand will be invoked right away
// wherever the writes complete (could even be invoked synchronously if no
// writes need to occur); this is useful when the current thread cannot pump
// messages to observe the reply (e.g. nested loops banned on main thread
// during shutdown). |synchronous_done_callback| must be thread-safe.
virtual void CommitPendingWrite(
base::OnceClosure reply_callback = base::OnceClosure(),
base::OnceClosure synchronous_done_callback = base::OnceClosure());
// Schedules a write if there is any lossy data pending. Unlike
// CommitPendingWrite() this does not immediately sync to disk, instead it
// triggers an eventual write if there is lossy data pending and if there
// isn't one scheduled already.
virtual void SchedulePendingLossyWrites() = 0;
// Cleans preference data that may have been saved outside of the store.
virtual void OnStoreDeletionFromDisk() = 0;
// TODO(crbug.com/41447167) Remove this after fixing the bug.
virtual bool IsInMemoryPrefStore() const;
// Returns whether this holds a read error delegate (can be null), passed
// during ReadPrefsAsync().
// When used in conjugation with IsInitializationComplete() and
// GetReadError(), this can be used to identity if there's a pending read.
virtual bool HasReadErrorDelegate() const = 0;
// Returns this store's filter, or nullptr if it has none.
virtual PrefFilter* GetFilter();
// Returns the default store filter used by SegregatedPrefStore.
// Returns nullptr by default.
virtual PrefFilter* GetDefaultStoreFilter();
// Returns the selected store filter used by SegregatedPrefStore.
// Returns nullptr by default.
virtual PrefFilter* GetSelectedStoreFilter();
protected:
~PersistentPrefStore() override = default;
};
#endif // COMPONENTS_PREFS_PERSISTENT_PREF_STORE_H_
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