| // Copyright 2013 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_PREF_FILTER_H_ |
| #define BASE_PREFS_PREF_FILTER_H_ |
| |
| #include <string> |
| |
| #include "base/callback_forward.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/prefs/base_prefs_export.h" |
| |
| namespace base { |
| class DictionaryValue; |
| class Value; |
| } // namespace base |
| |
| // Filters preferences as they are loaded from disk or updated at runtime. |
| // Currently supported only by JsonPrefStore. |
| class BASE_PREFS_EXPORT PrefFilter { |
| public: |
| // A callback to be invoked when |prefs| have been read (and possibly |
| // pre-modified) and are now ready to be handed back to this callback's |
| // builder. |schedule_write| indicates whether a write should be immediately |
| // scheduled (typically because the |prefs| were pre-modified). |
| typedef base::Callback<void(scoped_ptr<base::DictionaryValue> prefs, |
| bool schedule_write)> PostFilterOnLoadCallback; |
| |
| virtual ~PrefFilter() {} |
| |
| // This method is given ownership of the |pref_store_contents| read from disk |
| // before the underlying PersistentPrefStore gets to use them. It must hand |
| // them back via |post_filter_on_load_callback|, but may modify them first. |
| // Note: This method is asynchronous, which may make calls like |
| // PersistentPrefStore::ReadPrefs() asynchronous. The owner of filtered |
| // PersistentPrefStores should handle this to make the reads look synchronous |
| // to external users (see SegregatedPrefStore::ReadPrefs() for an example). |
| virtual void FilterOnLoad( |
| const PostFilterOnLoadCallback& post_filter_on_load_callback, |
| scoped_ptr<base::DictionaryValue> pref_store_contents) = 0; |
| |
| // Receives notification when a pref store value is changed, before Observers |
| // are notified. |
| virtual void FilterUpdate(const std::string& path) = 0; |
| |
| // Receives notification when the pref store is about to serialize data |
| // contained in |pref_store_contents| to a string. Modifications to |
| // |pref_store_contents| will be persisted to disk and also affect the |
| // in-memory state. |
| virtual void FilterSerializeData( |
| base::DictionaryValue* pref_store_contents) = 0; |
| }; |
| |
| #endif // BASE_PREFS_PREF_FILTER_H_ |