1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROME_BROWSER_SYNC_GLUE_SHARED_CHANGE_PROCESSOR_H_ 6 #define CHROME_BROWSER_SYNC_GLUE_SHARED_CHANGE_PROCESSOR_H_ 7 8 #include "base/location.h" 9 #include "base/memory/ref_counted.h" 10 #include "base/memory/weak_ptr.h" 11 #include "base/message_loop/message_loop_proxy.h" 12 #include "base/synchronization/lock.h" 13 #include "chrome/browser/sync/glue/data_type_error_handler.h" 14 #include "sync/api/sync_change_processor.h" 15 #include "sync/api/sync_error.h" 16 #include "sync/api/sync_error_factory.h" 17 #include "sync/api/sync_merge_result.h" 18 #include "sync/internal_api/public/engine/model_safe_worker.h" 19 20 class ProfileSyncComponentsFactory; 21 class ProfileSyncService; 22 23 namespace syncer { 24 class SyncData; 25 class SyncableService; 26 27 typedef std::vector<syncer::SyncData> SyncDataList; 28 } // namespace 29 30 namespace browser_sync { 31 32 class GenericChangeProcessor; 33 class DataTypeErrorHandler; 34 35 // A ref-counted wrapper around a GenericChangeProcessor for use with datatypes 36 // that don't live on the UI thread. 37 // 38 // We need to make it refcounted as the ownership transfer from the 39 // DataTypeController is dependent on threading, and hence racy. The 40 // SharedChangeProcessor should be created on the UI thread, but should only be 41 // connected and used on the same thread as the datatype it interacts with. 42 // 43 // The only thread-safe method is Disconnect, which will disconnect from the 44 // generic change processor, letting us shut down the syncer/datatype without 45 // waiting for non-UI threads. 46 // 47 // Note: since we control the work being done while holding the lock, we ensure 48 // no I/O or other intensive work is done while blocking the UI thread (all 49 // the work is in-memory sync interactions). 50 // 51 // We use virtual methods so that we can use mock's in testing. 52 class SharedChangeProcessor 53 : public base::RefCountedThreadSafe<SharedChangeProcessor> { 54 public: 55 // Create an uninitialized SharedChangeProcessor (to be later connected). 56 SharedChangeProcessor(); 57 58 // Connect to the Syncer and prepare to handle changes for |type|. Will 59 // create and store a new GenericChangeProcessor and return a weak pointer to 60 // the syncer::SyncableService associated with |type|. 61 // Note: If this SharedChangeProcessor has been disconnected, or the 62 // syncer::SyncableService was not alive, will return a null weak pointer. 63 virtual base::WeakPtr<syncer::SyncableService> Connect( 64 ProfileSyncComponentsFactory* sync_factory, 65 ProfileSyncService* sync_service, 66 DataTypeErrorHandler* error_handler, 67 syncer::ModelType type, 68 const base::WeakPtr<syncer::SyncMergeResult>& merge_result); 69 70 // Disconnects from the generic change processor. May be called from any 71 // thread. After this, all attempts to interact with the change processor by 72 // |local_service_| are dropped and return errors. The syncer will be safe to 73 // shut down from the point of view of this datatype. 74 // Note: Once disconnected, you cannot reconnect without creating a new 75 // SharedChangeProcessor. 76 // Returns: true if we were previously succesfully connected, false if we were 77 // already disconnected. 78 virtual bool Disconnect(); 79 80 // GenericChangeProcessor stubs (with disconnect support). 81 // Should only be called on the same thread the datatype resides. 82 virtual syncer::SyncError GetSyncData( 83 syncer::SyncDataList* current_sync_data); 84 virtual int GetSyncCount(); 85 virtual syncer::SyncError ProcessSyncChanges( 86 const tracked_objects::Location& from_here, 87 const syncer::SyncChangeList& change_list); 88 virtual bool SyncModelHasUserCreatedNodes(bool* has_nodes); 89 virtual bool CryptoReadyIfNecessary(); 90 91 // Register |generic_change_processor_| as the change processor for the 92 // current type on |model_safe_group|. 93 // Does nothing if |disconnected_| is true. 94 virtual void ActivateDataType(syncer::ModelSafeGroup model_safe_group); 95 96 virtual syncer::SyncError CreateAndUploadError( 97 const tracked_objects::Location& location, 98 const std::string& message); 99 100 protected: 101 friend class base::RefCountedThreadSafe<SharedChangeProcessor>; 102 virtual ~SharedChangeProcessor(); 103 104 private: 105 // Monitor lock for this object. All methods that interact with the change 106 // processor must aquire this lock and check whether we're disconnected or 107 // not. Once disconnected, all attempted changes to or loads from the change 108 // processor return errors. This enables us to shut down the syncer without 109 // having to wait for possibly non-UI thread datatypes to complete work. 110 mutable base::Lock monitor_lock_; 111 bool disconnected_; 112 113 // The sync datatype we were last connected to. 114 syncer::ModelType type_; 115 116 // The ProfileSyncService we're currently connected to. 117 ProfileSyncService* sync_service_; 118 119 // The loop that all methods except the constructor, destructor, and 120 // Disconnect() should be called on. Set in Connect(). 121 scoped_refptr<base::MessageLoopProxy> backend_loop_; 122 123 // Used only on |backend_loop_|. 124 GenericChangeProcessor* generic_change_processor_; 125 126 DataTypeErrorHandler* error_handler_; 127 128 DISALLOW_COPY_AND_ASSIGN(SharedChangeProcessor); 129 }; 130 131 } // namespace browser_sync 132 133 #endif // CHROME_BROWSER_SYNC_GLUE_SHARED_CHANGE_PROCESSOR_H_ 134
