1 // Copyright 2012 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef COMPONENTS_PREFS_PERSISTENT_PREF_STORE_H_
6 #define COMPONENTS_PREFS_PERSISTENT_PREF_STORE_H_
8 #include "base/functional/callback.h"
9 #include "components/prefs/prefs_export.h"
10 #include "components/prefs/writeable_pref_store.h"
12 // This interface is complementary to the PrefStore interface, declaring
13 // additional functionality that adds support for setting values and persisting
14 // the data to some backing store.
15 class COMPONENTS_PREFS_EXPORT PersistentPrefStore : public WriteablePrefStore {
17 // Unique integer code for each type of error so we can report them
18 // distinctly in a histogram.
19 // NOTE: Don't change the explicit values of the enums as it will change the
20 // server's meaning of the histogram.
22 PREF_READ_ERROR_NONE = 0,
23 PREF_READ_ERROR_JSON_PARSE = 1,
24 PREF_READ_ERROR_JSON_TYPE = 2,
25 PREF_READ_ERROR_ACCESS_DENIED = 3,
26 PREF_READ_ERROR_FILE_OTHER = 4,
27 PREF_READ_ERROR_FILE_LOCKED = 5,
28 PREF_READ_ERROR_NO_FILE = 6,
29 PREF_READ_ERROR_JSON_REPEAT = 7,
30 // PREF_READ_ERROR_OTHER = 8, // Deprecated.
31 PREF_READ_ERROR_FILE_NOT_SPECIFIED = 9,
32 // Indicates that ReadPrefs() couldn't complete synchronously and is waiting
33 // for an asynchronous task to complete first.
34 PREF_READ_ERROR_ASYNCHRONOUS_TASK_INCOMPLETE = 10,
35 PREF_READ_ERROR_MAX_ENUM
38 class ReadErrorDelegate {
40 virtual ~ReadErrorDelegate() {}
42 virtual void OnError(PrefReadError error) = 0;
45 // Whether the store is in a pseudo-read-only mode where changes are not
46 // actually persisted to disk. This happens in some cases when there are
47 // read errors during startup.
48 virtual bool ReadOnly() const = 0;
50 // Gets the read error. Only valid if IsInitializationComplete() returns true.
51 virtual PrefReadError GetReadError() const = 0;
53 // Reads the preferences from disk. Notifies observers via
54 // "PrefStore::OnInitializationCompleted" when done.
55 virtual PrefReadError ReadPrefs() = 0;
57 // Reads the preferences from disk asynchronously. Notifies observers via
58 // "PrefStore::OnInitializationCompleted" when done. Also it fires
59 // |error_delegate| if it is not NULL and reading error has occurred.
60 // Owns |error_delegate|.
61 virtual void ReadPrefsAsync(ReadErrorDelegate* error_delegate) = 0;
63 // Lands pending writes to disk. |reply_callback| will be posted to the
64 // current sequence when changes have been written.
65 // |synchronous_done_callback| on the other hand will be invoked right away
66 // wherever the writes complete (could even be invoked synchronously if no
67 // writes need to occur); this is useful when the current thread cannot pump
68 // messages to observe the reply (e.g. nested loops banned on main thread
69 // during shutdown). |synchronous_done_callback| must be thread-safe.
70 virtual void CommitPendingWrite(
71 base::OnceClosure reply_callback = base::OnceClosure(),
72 base::OnceClosure synchronous_done_callback = base::OnceClosure());
74 // Schedules a write if there is any lossy data pending. Unlike
75 // CommitPendingWrite() this does not immediately sync to disk, instead it
76 // triggers an eventual write if there is lossy data pending and if there
77 // isn't one scheduled already.
78 virtual void SchedulePendingLossyWrites() = 0;
80 // Cleans preference data that may have been saved outside of the store.
81 virtual void OnStoreDeletionFromDisk() = 0;
83 // TODO(crbug.com/942491) Remove this after fixing the bug.
84 virtual bool IsInMemoryPrefStore() const;
87 ~PersistentPrefStore() override {}
90 #endif // COMPONENTS_PREFS_PERSISTENT_PREF_STORE_H_