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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
3 // found in the LICENSE file.
4 
5 #include "sync/engine/sync_directory_update_handler.h"
6 
7 #include "sync/engine/conflict_resolver.h"
8 #include "sync/engine/process_updates_util.h"
9 #include "sync/engine/update_applicator.h"
10 #include "sync/sessions/status_controller.h"
11 #include "sync/syncable/directory.h"
12 #include "sync/syncable/syncable_model_neutral_write_transaction.h"
13 #include "sync/syncable/syncable_write_transaction.h"
14 
15 namespace syncer {
16 
17 using syncable::SYNCER;
18 
SyncDirectoryUpdateHandler(syncable::Directory * dir,ModelType type,scoped_refptr<ModelSafeWorker> worker)19 SyncDirectoryUpdateHandler::SyncDirectoryUpdateHandler(
20     syncable::Directory* dir,
21     ModelType type,
22     scoped_refptr<ModelSafeWorker> worker)
23   : dir_(dir),
24     type_(type),
25     worker_(worker) {}
26 
~SyncDirectoryUpdateHandler()27 SyncDirectoryUpdateHandler::~SyncDirectoryUpdateHandler() {}
28 
GetDownloadProgress(sync_pb::DataTypeProgressMarker * progress_marker) const29 void SyncDirectoryUpdateHandler::GetDownloadProgress(
30     sync_pb::DataTypeProgressMarker* progress_marker) const {
31   dir_->GetDownloadProgress(type_, progress_marker);
32 }
33 
ProcessGetUpdatesResponse(const sync_pb::DataTypeProgressMarker & progress_marker,const SyncEntityList & applicable_updates,sessions::StatusController * status)34 void SyncDirectoryUpdateHandler::ProcessGetUpdatesResponse(
35     const sync_pb::DataTypeProgressMarker& progress_marker,
36     const SyncEntityList& applicable_updates,
37     sessions::StatusController* status) {
38   syncable::ModelNeutralWriteTransaction trans(FROM_HERE, SYNCER, dir_);
39   UpdateSyncEntities(&trans, applicable_updates, status);
40   UpdateProgressMarker(progress_marker);
41 }
42 
ApplyUpdates(sessions::StatusController * status)43 void SyncDirectoryUpdateHandler::ApplyUpdates(
44     sessions::StatusController* status) {
45   if (IsControlType(type_)) {
46     return;  // We don't process control types here.
47   }
48 
49   if (!dir_->TypeHasUnappliedUpdates(type_)) {
50     return;  // No work to do.  Skip this type.
51   }
52 
53   WorkCallback c = base::Bind(
54       &SyncDirectoryUpdateHandler::ApplyUpdatesImpl,
55       // We wait until the callback is executed.  We can safely use Unretained.
56       base::Unretained(this),
57       base::Unretained(status));
58   worker_->DoWorkAndWaitUntilDone(c);
59 }
60 
ApplyUpdatesImpl(sessions::StatusController * status)61 SyncerError SyncDirectoryUpdateHandler::ApplyUpdatesImpl(
62     sessions::StatusController* status) {
63   syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir_);
64 
65   std::vector<int64> handles;
66   dir_->GetUnappliedUpdateMetaHandles(
67       &trans,
68       FullModelTypeSet(type_),
69       &handles);
70 
71   // First set of update application passes.
72   UpdateApplicator applicator(dir_->GetCryptographer(&trans));
73   applicator.AttemptApplications(&trans, handles);
74   status->increment_num_updates_applied_by(applicator.updates_applied());
75   status->increment_num_hierarchy_conflicts_by(
76       applicator.hierarchy_conflicts());
77   status->increment_num_encryption_conflicts_by(
78       applicator.encryption_conflicts());
79 
80   if (applicator.simple_conflict_ids().size() != 0) {
81     // Resolve the simple conflicts we just detected.
82     ConflictResolver resolver;
83     resolver.ResolveConflicts(&trans,
84                               dir_->GetCryptographer(&trans),
85                               applicator.simple_conflict_ids(),
86                               status);
87 
88     // Conflict resolution sometimes results in more updates to apply.
89     handles.clear();
90     dir_->GetUnappliedUpdateMetaHandles(
91         &trans,
92         FullModelTypeSet(type_),
93         &handles);
94 
95     UpdateApplicator conflict_applicator(dir_->GetCryptographer(&trans));
96     conflict_applicator.AttemptApplications(&trans, handles);
97 
98     // We count the number of updates from both applicator passes.
99     status->increment_num_updates_applied_by(
100         conflict_applicator.updates_applied());
101 
102     // Encryption conflicts should remain unchanged by the resolution of simple
103     // conflicts.  Those can only be solved by updating our nigori key bag.
104     DCHECK_EQ(conflict_applicator.encryption_conflicts(),
105               applicator.encryption_conflicts());
106 
107     // Hierarchy conflicts should also remain unchanged, for reasons that are
108     // more subtle.  Hierarchy conflicts exist when the application of a pending
109     // update from the server would make the local folder hierarchy
110     // inconsistent.  The resolution of simple conflicts could never affect the
111     // hierarchy conflicting item directly, because hierarchy conflicts are not
112     // processed by the conflict resolver.  It could, in theory, modify the
113     // local hierarchy on which hierarchy conflict detection depends.  However,
114     // the conflict resolution algorithm currently in use does not allow this.
115     DCHECK_EQ(conflict_applicator.hierarchy_conflicts(),
116               applicator.hierarchy_conflicts());
117 
118     // There should be no simple conflicts remaining.  We know this because the
119     // resolver should have resolved all the conflicts we detected last time
120     // and, by the two previous assertions, that no conflicts have been
121     // downgraded from encryption or hierarchy down to simple.
122     DCHECK(conflict_applicator.simple_conflict_ids().empty());
123   }
124 
125   return SYNCER_OK;
126 }
127 
UpdateSyncEntities(syncable::ModelNeutralWriteTransaction * trans,const SyncEntityList & applicable_updates,sessions::StatusController * status)128 void SyncDirectoryUpdateHandler::UpdateSyncEntities(
129     syncable::ModelNeutralWriteTransaction* trans,
130     const SyncEntityList& applicable_updates,
131     sessions::StatusController* status) {
132   ProcessDownloadedUpdates(dir_, trans, type_, applicable_updates, status);
133 }
134 
UpdateProgressMarker(const sync_pb::DataTypeProgressMarker & progress_marker)135 void SyncDirectoryUpdateHandler::UpdateProgressMarker(
136     const sync_pb::DataTypeProgressMarker& progress_marker) {
137   int field_number = progress_marker.data_type_id();
138   ModelType model_type = GetModelTypeFromSpecificsFieldNumber(field_number);
139   if (!IsRealDataType(model_type) || type_ != model_type) {
140     NOTREACHED()
141         << "Update handler of type " << ModelTypeToString(type_)
142         << " asked to process progress marker with invalid type "
143         << field_number;
144   }
145   dir_->SetDownloadProgress(type_, progress_marker);
146 }
147 
148 }  // namespace syncer
149