1 // Copyright 2014 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.
5 #ifndef SYNC_ENGINE_NON_BLOCKING_TYPE_PROCESSOR_CORE_H_
6 #define SYNC_ENGINE_NON_BLOCKING_TYPE_PROCESSOR_CORE_H_
8 #include "base/memory/weak_ptr.h"
9 #include "base/stl_util.h"
10 #include "base/threading/non_thread_safe.h"
11 #include "sync/base/sync_export.h"
12 #include "sync/engine/commit_contributor.h"
13 #include "sync/engine/non_blocking_sync_common.h"
14 #include "sync/engine/update_handler.h"
15 #include "sync/internal_api/public/base/model_type.h"
16 #include "sync/protocol/sync.pb.h"
19 class SingleThreadTaskRunner;
24 class NonBlockingTypeProcessorInterface;
25 class SyncThreadSyncEntity;
27 // A smart cache for sync types that use message passing (rather than
28 // transactions and the syncable::Directory) to communicate with the sync
31 // When the non-blocking sync type wants to talk with the sync server, it will
32 // send a message from its thread to this object on the sync thread. This
33 // object ensures the appropriate sync server communication gets scheduled and
34 // executed. The response, if any, will be returned to the non-blocking sync
35 // type's thread eventually.
37 // This object also has a role to play in communications in the opposite
38 // direction. Sometimes the sync thread will receive changes from the sync
39 // server and deliver them here. This object will post this information back to
40 // the appropriate component on the model type's thread.
42 // This object does more than just pass along messages. It understands the sync
43 // protocol, and it can make decisions when it sees conflicting messages. For
44 // example, if the sync server sends down an update for a sync entity that is
45 // currently pending for commit, this object will detect this condition and
46 // cancel the pending commit.
47 class SYNC_EXPORT NonBlockingTypeProcessorCore
48 : public UpdateHandler,
49 public CommitContributor,
50 public base::NonThreadSafe {
52 NonBlockingTypeProcessorCore(
54 const DataTypeState& initial_state,
55 scoped_ptr<NonBlockingTypeProcessorInterface> processor_interface);
56 virtual ~NonBlockingTypeProcessorCore();
58 ModelType GetModelType() const;
60 // UpdateHandler implementation.
61 virtual void GetDownloadProgress(
62 sync_pb::DataTypeProgressMarker* progress_marker) const OVERRIDE;
63 virtual void GetDataTypeContext(sync_pb::DataTypeContext* context) const
65 virtual SyncerError ProcessGetUpdatesResponse(
66 const sync_pb::DataTypeProgressMarker& progress_marker,
67 const sync_pb::DataTypeContext& mutated_context,
68 const SyncEntityList& applicable_updates,
69 sessions::StatusController* status) OVERRIDE;
70 virtual void ApplyUpdates(sessions::StatusController* status) OVERRIDE;
71 virtual void PassiveApplyUpdates(sessions::StatusController* status) OVERRIDE;
73 // Entry point for NonBlockingTypeProcessor to send commit requests.
74 void EnqueueForCommit(const CommitRequestDataList& request_list);
76 // CommitContributor implementation.
77 virtual scoped_ptr<CommitContribution> GetContribution(
78 size_t max_entries) OVERRIDE;
80 // Callback for when our contribution gets a response.
81 void OnCommitResponse(const CommitResponseDataList& response_list);
83 base::WeakPtr<NonBlockingTypeProcessorCore> AsWeakPtr();
86 typedef std::map<std::string, SyncThreadSyncEntity*> EntityMap;
88 // Stores a single commit request in this object's internal state.
89 void StorePendingCommit(const CommitRequestData& request);
91 // Returns true if all data type state required for commits is available. In
92 // practice, this means that it returns true from the time this object first
93 // receives notice of a successful update fetch from the server.
94 bool CanCommitItems() const;
96 // Initializes the parts of a commit entity that are the responsibility of
97 // this class, and not the SyncThreadSyncEntity. Some fields, like the
98 // client-assigned ID, can only be set by an entity with knowledge of the
99 // entire data type's state.
100 void HelpInitializeCommitEntity(sync_pb::SyncEntity* commit_entity);
104 // State that applies to the entire model type.
105 DataTypeState data_type_state_;
107 // Abstraction around the NonBlockingTypeProcessor so this class
108 // doesn't need to know about its specific implementation or
109 // which thread it's on. This makes it easier to write tests.
110 scoped_ptr<NonBlockingTypeProcessorInterface> processor_interface_;
112 // A map of per-entity information known to this object.
114 // When commits are pending, their information is stored here. This
115 // information is dropped from memory when the commit succeeds or gets
118 // This also stores some information related to received server state in
119 // order to implement reflection blocking and conflict detection. This
120 // information is kept in memory indefinitely. With a bit more coordination
121 // with the model thread, we could optimize this to reduce memory usage in
124 STLValueDeleter<EntityMap> entities_deleter_;
126 base::WeakPtrFactory<NonBlockingTypeProcessorCore> weak_ptr_factory_;
129 } // namespace syncer
131 #endif // SYNC_ENGINE_NON_BLOCKING_TYPE_PROCESSOR_CORE_H_