sync/internal_api/public/engine/model_safe_worker.cc

   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 #include "sync/internal_api/public/engine/model_safe_worker.h"
   6
   7 #include "base/bind.h"
   8 #include "base/json/json_writer.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/values.h"
  11
  12 namespace syncer {
  13
  14 base::DictionaryValue* ModelSafeRoutingInfoToValue(
  15     const ModelSafeRoutingInfo& routing_info) {
  16   base::DictionaryValue* dict = new base::DictionaryValue();
  17   for (ModelSafeRoutingInfo::const_iterator it = routing_info.begin();
  18        it != routing_info.end(); ++it) {
  19     dict->SetString(ModelTypeToString(it->first),
  20                     ModelSafeGroupToString(it->second));
  21   }
  22   return dict;
  23 }
  24
  25 std::string ModelSafeRoutingInfoToString(
  26     const ModelSafeRoutingInfo& routing_info) {
  27   scoped_ptr<base::DictionaryValue> dict(
  28       ModelSafeRoutingInfoToValue(routing_info));
  29   std::string json;
  30   base::JSONWriter::Write(dict.get(), &json);
  31   return json;
  32 }
  33
  34 ModelTypeSet GetRoutingInfoTypes(const ModelSafeRoutingInfo& routing_info) {
  35   ModelTypeSet types;
  36   for (ModelSafeRoutingInfo::const_iterator it = routing_info.begin();
  37        it != routing_info.end(); ++it) {
  38     types.Put(it->first);
  39   }
  40   return types;
  41 }
  42
  43 ModelSafeGroup GetGroupForModelType(const ModelType type,
  44                                     const ModelSafeRoutingInfo& routes) {
  45   ModelSafeRoutingInfo::const_iterator it = routes.find(type);
  46   if (it == routes.end()) {
  47     if (type != UNSPECIFIED && type != TOP_LEVEL_FOLDER)
  48       DVLOG(1) << "Entry does not belong to active ModelSafeGroup!";
  49     return GROUP_PASSIVE;
  50   }
  51   return it->second;
  52 }
  53
  54 std::string ModelSafeGroupToString(ModelSafeGroup group) {
  55   switch (group) {
  56     case GROUP_UI:
  57       return "GROUP_UI";
  58     case GROUP_DB:
  59       return "GROUP_DB";
  60     case GROUP_FILE:
  61       return "GROUP_FILE";
  62     case GROUP_HISTORY:
  63       return "GROUP_HISTORY";
  64     case GROUP_PASSIVE:
  65       return "GROUP_PASSIVE";
  66     case GROUP_PASSWORD:
  67       return "GROUP_PASSWORD";
  68     default:
  69       NOTREACHED();
  70       return "INVALID";
  71   }
  72 }
  73
  74 ModelSafeWorker::ModelSafeWorker(WorkerLoopDestructionObserver* observer)
  75     : stopped_(false),
  76       work_done_or_stopped_(false, false),
  77       observer_(observer),
  78       working_loop_(NULL) {
  79 }
  80
  81 ModelSafeWorker::~ModelSafeWorker() {}
  82
  83 void ModelSafeWorker::RequestStop() {
  84   base::AutoLock al(stopped_lock_);
  85
  86   // Set stop flag but don't signal work_done_or_stopped_ to unblock sync loop
  87   // because the worker may be working and depending on sync command object
  88   // living on sync thread. his prevents any *further* tasks from being posted
  89   // to worker threads (see DoWorkAndWaitUntilDone below), but note that one
  90   // may already be posted.
  91   stopped_ = true;
  92 }
  93
  94 SyncerError ModelSafeWorker::DoWorkAndWaitUntilDone(const WorkCallback& work) {
  95   {
  96     base::AutoLock al(stopped_lock_);
  97     if (stopped_)
  98       return CANNOT_DO_WORK;
  99
 100     CHECK(!work_done_or_stopped_.IsSignaled());
 101   }
 102
 103   return DoWorkAndWaitUntilDoneImpl(work);
 104 }
 105
 106 bool ModelSafeWorker::IsStopped() {
 107   base::AutoLock al(stopped_lock_);
 108   return stopped_;
 109 }
 110
 111 void ModelSafeWorker::WillDestroyCurrentMessageLoop() {
 112   {
 113     base::AutoLock al(stopped_lock_);
 114     stopped_ = true;
 115
 116     // Must signal to unblock syncer if it's waiting for a posted task to
 117     // finish. At this point, all pending tasks posted to the loop have been
 118     // destroyed (see MessageLoop::~MessageLoop). So syncer will be blocked
 119     // indefinitely without signaling here.
 120     work_done_or_stopped_.Signal();
 121
 122     DVLOG(1) << ModelSafeGroupToString(GetModelSafeGroup())
 123         << " worker stops on destruction of its working thread.";
 124   }
 125
 126   {
 127     base::AutoLock l(working_loop_lock_);
 128     working_loop_ = NULL;
 129   }
 130
 131   if (observer_)
 132     observer_->OnWorkerLoopDestroyed(GetModelSafeGroup());
 133 }
 134
 135 void ModelSafeWorker::SetWorkingLoopToCurrent() {
 136   base::Callback<void(ModelSafeGroup)> unregister_done_callback;
 137
 138   {
 139     base::AutoLock l(working_loop_lock_);
 140     DCHECK(!working_loop_);
 141
 142     if (unregister_done_callback_.is_null()) {
 143       // Expected case - UnregisterForLoopDestruction hasn't been called yet.
 144       base::MessageLoop::current()->AddDestructionObserver(this);
 145       working_loop_ = base::MessageLoop::current();
 146     } else {
 147       // Rare case which is possible when the model type thread remains
 148       // blocked for the entire session and UnregisterForLoopDestruction ends
 149       // up being called before this method. This method is posted unlike
 150       // UnregisterForLoopDestruction - that's why they can end up being called
 151       // out of order.
 152       // In this case we skip the destruction observer registration
 153       // and just invoke the callback stored at UnregisterForLoopDestruction.
 154       DCHECK(stopped_);
 155       unregister_done_callback = unregister_done_callback_;
 156       unregister_done_callback_.Reset();
 157     }
 158   }
 159
 160   if (!unregister_done_callback.is_null()) {
 161     unregister_done_callback.Run(GetModelSafeGroup());
 162   }
 163 }
 164
 165 void ModelSafeWorker::UnregisterForLoopDestruction(
 166     base::Callback<void(ModelSafeGroup)> unregister_done_callback) {
 167   base::AutoLock l(working_loop_lock_);
 168   if (working_loop_ != NULL) {
 169     // Normal case - observer registration has been already done.
 170     // Delegate to the sync thread to do the actual unregistration in
 171     // UnregisterForLoopDestructionAsync.
 172     DCHECK_NE(base::MessageLoop::current(), working_loop_);
 173     working_loop_->PostTask(
 174         FROM_HERE,
 175         base::Bind(&ModelSafeWorker::UnregisterForLoopDestructionAsync,
 176                    this,
 177                    unregister_done_callback));
 178   } else {
 179     // The working loop is still unknown, probably because the model type
 180     // thread is blocked. Store the callback to be called from
 181     // SetWorkingLoopToCurrent.
 182     unregister_done_callback_ = unregister_done_callback;
 183   }
 184 }
 185
 186 void ModelSafeWorker::UnregisterForLoopDestructionAsync(
 187     base::Callback<void(ModelSafeGroup)> unregister_done_callback) {
 188   {
 189     base::AutoLock l(working_loop_lock_);
 190     if (!working_loop_)
 191       return;
 192     DCHECK_EQ(base::MessageLoop::current(), working_loop_);
 193   }
 194
 195   DCHECK(stopped_);
 196   base::MessageLoop::current()->RemoveDestructionObserver(this);
 197   unregister_done_callback.Run(GetModelSafeGroup());
 198 }
 199
 200 }  // namespace syncer