sync: rewrite DataTypeManagerImpl without pause/resume logic.

chrome/browser/sync/glue/data_type_manager_impl2.cc

+// Copyright (c) 2011 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.
+
+#include "chrome/browser/sync/glue/data_type_manager_impl2.h"
+
+#include "base/compiler_specific.h"
+#include "base/logging.h"
+#include "chrome/browser/browser_thread.h"
+#include "chrome/browser/sync/glue/data_type_controller.h"
+#include "chrome/browser/sync/glue/sync_backend_host.h"
+#include "chrome/common/notification_details.h"
+#include "chrome/common/notification_service.h"
+#include "chrome/common/notification_source.h"
+
+namespace browser_sync {
+
+namespace {
+
+static const syncable::ModelType kStartOrder[] = {
+  syncable::NIGORI,

[Nicolas Zea, 2011/02/16 18:40:53]

Presumably this is just for the sake of being complete? If so, a comment noting
that Nigori doesn't actually have a datatype controller/change processor would
be helpful.

[tim (not reviewing), 2011/02/17 21:27:25]

Done.

+  syncable::BOOKMARKS,
+  syncable::PREFERENCES,
+  syncable::AUTOFILL,
+  syncable::AUTOFILL_PROFILE,
+  syncable::EXTENSIONS,
+  syncable::APPS,
+  syncable::THEMES,
+  syncable::TYPED_URLS,
+  syncable::PASSWORDS,
+  syncable::SESSIONS,
+};
+
+COMPILE_ASSERT(arraysize(kStartOrder) ==
+               syncable::MODEL_TYPE_COUNT - syncable::FIRST_REAL_MODEL_TYPE,
+               kStartOrder_IncorrectSize);
+
+// Comparator used when sorting data type controllers.
+class SortComparator : public std::binary_function<DataTypeController*,
+                                                   DataTypeController*,
+                                                   bool> {
+ public:
+  explicit SortComparator(std::map<syncable::ModelType, int>* order)
+      : order_(order) { }
+
+  // Returns true if lhs precedes rhs.
+  bool operator() (DataTypeController* lhs, DataTypeController* rhs) {
+    return (*order_)[lhs->type()] < (*order_)[rhs->type()];
+  }
+
+ private:
+  std::map<syncable::ModelType, int>* order_;
+};
+
+}  // namespace
+
+DataTypeManagerImpl2::DataTypeManagerImpl2(SyncBackendHost* backend,
+    const DataTypeController::TypeMap& controllers)
+    : backend_(backend),
+      controllers_(controllers),
+      state_(DataTypeManager::STOPPED),
+      current_dtc_(NULL),
+      method_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
+  DCHECK(backend_);
+  // Ensure all data type controllers are stopped.
+  for (DataTypeController::TypeMap::const_iterator it = controllers_.begin();
+       it != controllers_.end(); ++it) {
+    DCHECK_EQ(DataTypeController::NOT_RUNNING, (*it).second->state());
+  }
+
+  // Build a ModelType -> order map for sorting.
+  for (int i = 0; i < static_cast<int>(arraysize(kStartOrder)); i++)
+    start_order_[kStartOrder[i]] = i;
+}
+
+DataTypeManagerImpl2::~DataTypeManagerImpl2() {}
+
+void DataTypeManagerImpl2::Configure(const TypeSet& desired_types) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (state_ == STOPPING) {
+    // You can not set a configuration while stopping.
+    LOG(ERROR) << "Configuration set while stopping.";
+    return;
+  }
+
+  last_requested_types_ = desired_types;
+  // Add any data type controllers into the needs_start_ list that are
+  // currently NOT_RUNNING or STOPPING.
+  needs_start_.clear();
+  for (TypeSet::const_iterator it = desired_types.begin();
+       it != desired_types.end(); ++it) {
+    DataTypeController::TypeMap::const_iterator dtc = controllers_.find(*it);
+    if (dtc != controllers_.end() &&
+        (dtc->second->state() == DataTypeController::NOT_RUNNING ||
+         dtc->second->state() == DataTypeController::STOPPING)) {
+      needs_start_.push_back(dtc->second.get());
+      VLOG(1) << "Will start " << dtc->second->name();
+    }
+  }
+  // Sort these according to kStartOrder.
+  std::sort(needs_start_.begin(),
+            needs_start_.end(),
+            SortComparator(&start_order_));
+
+  // Add any data type controllers into that needs_stop_ list that are
+  // currently MODEL_STARTING, ASSOCIATING, or RUNNING.
+  needs_stop_.clear();
+  for (DataTypeController::TypeMap::const_iterator it = controllers_.begin();
+       it != controllers_.end(); ++it) {
+    DataTypeController* dtc = (*it).second;
+    if (desired_types.count(dtc->type()) == 0 && (
+            dtc->state() == DataTypeController::MODEL_STARTING ||
+            dtc->state() == DataTypeController::ASSOCIATING ||
+            dtc->state() == DataTypeController::RUNNING)) {
+      needs_stop_.push_back(dtc);
+      VLOG(1) << "Will stop " << dtc->name();
+    }
+  }
+  // Sort these according to kStartOrder.
+  std::sort(needs_stop_.begin(),
+            needs_stop_.end(),
+            SortComparator(&start_order_));
+
+  // If nothing changed, we're done.
+  if (needs_start_.size() == 0 && needs_stop_.size() == 0) {
+    state_ = CONFIGURED;
+    NotifyStart();
+    NotifyDone(OK);
+    return;
+  }
+
+  Restart();
+}
+
+void DataTypeManagerImpl2::Restart() {
+  VLOG(1) << "Restarting...";
+
+  // If we are currently waiting for an asynchronous process to
+  // complete, change our state to RESTARTING so those processes know
+  // that we want to start over when they finish.
+  if (state_ == DOWNLOAD_PENDING || state_ == CONFIGURING) {
+    state_ = RESTARTING;
+    return;
+  }
+
+  DCHECK(state_ == STOPPED || state_ == RESTARTING || state_ == CONFIGURED);
+  current_dtc_ = NULL;
+
+  // Starting from a "steady state" (stopped or configured) state
+  // should send a start notification.
+  if (state_ == STOPPED || state_ == CONFIGURED)
+    NotifyStart();
+
+  // Stop requested data types.
+  for (size_t i = 0; i < needs_stop_.size(); ++i) {
+    VLOG(1) << "Stopping " << needs_stop_[i]->name();
+    needs_stop_[i]->Stop();
+  }
+  needs_stop_.clear();
+
+  // Tell the backend about the new set of data types we wish to sync.
+  // The task will be invoked when updates are downloaded.
+  state_ = DOWNLOAD_PENDING;
+  backend_->ConfigureDataTypes(
+      controllers_,
+      last_requested_types_,
+      method_factory_.NewRunnableMethod(&DataTypeManagerImpl2::DownloadReady));
+}
+
+void DataTypeManagerImpl2::DownloadReady() {
+  DCHECK(state_ == DOWNLOAD_PENDING || state_ == RESTARTING);
+
+  // If we had a restart while waiting for downloads, just restart.
+  // Note: Restart() can cause DownloadReady to be directly invoked, so we post
+  // a task to avoid re-entrancy issues.
+  if (state_ == RESTARTING) {
+    MessageLoop::current()->PostTask(FROM_HERE,
+        method_factory_.NewRunnableMethod(&DataTypeManagerImpl2::Restart));
+    return;
+  }
+
+  state_ = CONFIGURING;
+  StartNextType();
+}
+
+void DataTypeManagerImpl2::StartNextType() {
+  // If there are any data types left to start, start the one at the
+  // front of the list.
+  if (needs_start_.size() > 0) {
+    current_dtc_ = needs_start_[0];
+    VLOG(1) << "Starting " << current_dtc_->name();
+    current_dtc_->Start(
+        NewCallback(this, &DataTypeManagerImpl2::TypeStartCallback));
+    return;
+  }
+
+  // If no more data types need starting, we're done.  Resume the sync

[Nicolas Zea, 2011/02/16 18:40:53]

"Resume sync backend" no longer applicable, right?

[tim (not reviewing), 2011/02/17 21:27:25]

Done.

+  // backend to finish.
+  DCHECK_EQ(state_, CONFIGURING);
+  state_ = CONFIGURED;
+  NotifyDone(OK);
+}
+
+void DataTypeManagerImpl2::TypeStartCallback(
+    DataTypeController::StartResult result) {
+  // When the data type controller invokes this callback, it must be
+  // on the UI thread.
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(current_dtc_);
+
+  if (state_ == RESTARTING) {
+    // If configuration changed while this data type was starting, we
+    // need to reset.  Resume the syncer.

[Nicolas Zea, 2011/02/16 18:40:53]

Same here.

[tim (not reviewing), 2011/02/17 21:27:25]

Done.

+    Restart();
+    return;
+  } else if (state_ == STOPPING) {
+    // If we reach this callback while stopping, this means that
+    // DataTypeManager::Stop() was called while the current data type
+    // was starting.  Now that it has finished starting, we can finish
+    // stopping the DataTypeManager.  This is considered an ABORT.
+    FinishStopAndNotify(ABORTED);
+    return;
+  } else if (state_ == STOPPED) {
+    // If our state_ is STOPPED, we have already stopped all of the data
+    // types.  We should not be getting callbacks from stopped data types.
+    LOG(ERROR) << "Start callback called by stopped data type!";
+    return;
+  }
+
+  // We're done with the data type at the head of the list -- remove it.
+  DataTypeController* started_dtc = current_dtc_;
+  DCHECK(needs_start_.size());
+  DCHECK_EQ(needs_start_[0], started_dtc);
+  needs_start_.erase(needs_start_.begin());
+  current_dtc_ = NULL;
+
+  // If the type started normally, continue to the next type.
+  // If the type is waiting for the cryptographer, continue to the next type.
+  // Once the cryptographer is ready, we'll attempt to restart this type.
+  if (result == DataTypeController::NEEDS_CRYPTO ||
+      result == DataTypeController::OK ||
+      result == DataTypeController::OK_FIRST_RUN) {
+    StartNextType();
+    return;
+  }
+
+  // Any other result is a fatal error.  Shut down any types we've
+  // managed to start up to this point and pass the result to the
+  // callback.
+  VLOG(1) << "Failed " << started_dtc->name();
+  ConfigureResult configure_result = DataTypeManager::ABORTED;
+  switch (result) {
+    case DataTypeController::ABORTED:
+      configure_result = DataTypeManager::ABORTED;
+      break;
+    case DataTypeController::ASSOCIATION_FAILED:
+      configure_result = DataTypeManager::ASSOCIATION_FAILED;
+      break;
+    case DataTypeController::UNRECOVERABLE_ERROR:
+      configure_result = DataTypeManager::UNRECOVERABLE_ERROR;
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+  FinishStopAndNotify(configure_result);
+}
+
+void DataTypeManagerImpl2::Stop() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (state_ == STOPPED)
+    return;
+
+  // If we are currently configuring, then the current type is in a
+  // partially started state.  Abort the startup of the current type,
+  // which will synchronously invoke the start callback.
+  if (state_ == CONFIGURING) {
+    state_ = STOPPING;
+    current_dtc_->Stop();
+    return;
+  }
+
+  const bool download_pending = state_ == DOWNLOAD_PENDING;
+  state_ = STOPPING;
+  if (download_pending) {
+    // If Stop() is called while waiting for download, cancel all
+    // outstanding tasks.
+    method_factory_.RevokeAll();
+    FinishStopAndNotify(ABORTED);
+    return;
+  }
+
+  FinishStop();
+}
+
+void DataTypeManagerImpl2::FinishStop() {
+  DCHECK(state_== CONFIGURING || state_ == STOPPING);
+  // Simply call the Stop() method on all running data types.
+  for (DataTypeController::TypeMap::const_iterator it = controllers_.begin();
+       it != controllers_.end(); ++it) {
+    DataTypeController* dtc = (*it).second;
+    if (dtc->state() != DataTypeController::NOT_RUNNING &&
+        dtc->state() != DataTypeController::STOPPING) {
+      dtc->Stop();
+      VLOG(1) << "Stopped " << dtc->name();
+    }
+  }
+  state_ = STOPPED;
+}
+
+void DataTypeManagerImpl2::FinishStopAndNotify(ConfigureResult result) {
+  FinishStop();
+  NotifyDone(result);
+}
+
+void DataTypeManagerImpl2::NotifyStart() {
+  NotificationService::current()->Notify(
+      NotificationType::SYNC_CONFIGURE_START,
+      Source<DataTypeManager>(this),
+      NotificationService::NoDetails());
+}
+
+void DataTypeManagerImpl2::NotifyDone(ConfigureResult result) {
+  NotificationService::current()->Notify(
+      NotificationType::SYNC_CONFIGURE_DONE,
+      Source<DataTypeManager>(this),
+      Details<ConfigureResult>(&result));
+}
+
+const DataTypeController::TypeMap& DataTypeManagerImpl2::controllers() {
+  return controllers_;
+}
+
+DataTypeManager::State DataTypeManagerImpl2::state() {
+  return state_;
+}
+
+}  // namespace browser_sync