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1 // Copyright 2013 The Chromium Authors. All rights reserved. | 1 // Copyright 2013 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef BASE_PREFS_PREF_FILTER_H_ | 5 // TODO(brettw) remove this forwarding header when prefs is completely moved to |
6 #define BASE_PREFS_PREF_FILTER_H_ | 6 // components. |
7 | 7 #include "components/prefs/pref_filter.h" |
8 #include <string> | |
9 | |
10 #include "base/callback_forward.h" | |
11 #include "base/memory/scoped_ptr.h" | |
12 #include "base/prefs/base_prefs_export.h" | |
13 | |
14 namespace base { | |
15 class DictionaryValue; | |
16 class Value; | |
17 } // namespace base | |
18 | |
19 // Filters preferences as they are loaded from disk or updated at runtime. | |
20 // Currently supported only by JsonPrefStore. | |
21 class BASE_PREFS_EXPORT PrefFilter { | |
22 public: | |
23 // A callback to be invoked when |prefs| have been read (and possibly | |
24 // pre-modified) and are now ready to be handed back to this callback's | |
25 // builder. |schedule_write| indicates whether a write should be immediately | |
26 // scheduled (typically because the |prefs| were pre-modified). | |
27 typedef base::Callback<void(scoped_ptr<base::DictionaryValue> prefs, | |
28 bool schedule_write)> PostFilterOnLoadCallback; | |
29 | |
30 virtual ~PrefFilter() {} | |
31 | |
32 // This method is given ownership of the |pref_store_contents| read from disk | |
33 // before the underlying PersistentPrefStore gets to use them. It must hand | |
34 // them back via |post_filter_on_load_callback|, but may modify them first. | |
35 // Note: This method is asynchronous, which may make calls like | |
36 // PersistentPrefStore::ReadPrefs() asynchronous. The owner of filtered | |
37 // PersistentPrefStores should handle this to make the reads look synchronous | |
38 // to external users (see SegregatedPrefStore::ReadPrefs() for an example). | |
39 virtual void FilterOnLoad( | |
40 const PostFilterOnLoadCallback& post_filter_on_load_callback, | |
41 scoped_ptr<base::DictionaryValue> pref_store_contents) = 0; | |
42 | |
43 // Receives notification when a pref store value is changed, before Observers | |
44 // are notified. | |
45 virtual void FilterUpdate(const std::string& path) = 0; | |
46 | |
47 // Receives notification when the pref store is about to serialize data | |
48 // contained in |pref_store_contents| to a string. Modifications to | |
49 // |pref_store_contents| will be persisted to disk and also affect the | |
50 // in-memory state. | |
51 virtual void FilterSerializeData( | |
52 base::DictionaryValue* pref_store_contents) = 0; | |
53 }; | |
54 | |
55 #endif // BASE_PREFS_PREF_FILTER_H_ | |
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