[Sync] Refactor non-frontend DTC to handle new API properly.

chrome/browser/sync/glue/generic_change_processor.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/generic_change_processor.h"
 
 #include "base/location.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/sync/api/syncable_service.h"
 #include "chrome/browser/sync/api/sync_change.h"
 #include "chrome/browser/sync/api/sync_error.h"
 #include "chrome/browser/sync/internal_api/base_node.h"
 #include "chrome/browser/sync/internal_api/change_record.h"
 #include "chrome/browser/sync/internal_api/read_node.h"
 #include "chrome/browser/sync/internal_api/read_transaction.h"
 #include "chrome/browser/sync/internal_api/write_node.h"
 #include "chrome/browser/sync/internal_api/write_transaction.h"
 #include "chrome/browser/sync/unrecoverable_error_handler.h"
 
+using base::AutoLock;
+
 namespace browser_sync {
 
 GenericChangeProcessor::GenericChangeProcessor(
+    UnrecoverableErrorHandler* error_handler)
+    : ChangeProcessor(error_handler),
+      local_service_(NULL),
+      user_share_(NULL),
+      disconnected_(false) {}
+
+GenericChangeProcessor::GenericChangeProcessor(
+    UnrecoverableErrorHandler* error_handler,
     SyncableService* local_service,
-    UnrecoverableErrorHandler* error_handler,
     sync_api::UserShare* user_share)
     : ChangeProcessor(error_handler),
-      local_service_(local_service),
-      user_share_(user_share) {
-  DCHECK(local_service_);
+      local_service_(NULL),
+      user_share_(NULL),
+      disconnected_(false) {
+  Connect(local_service, user_share);
 }
 
-GenericChangeProcessor::~GenericChangeProcessor() {
-  // Set to null to ensure it's not used after destruction.
-  local_service_ = NULL;
+GenericChangeProcessor::~GenericChangeProcessor() {}
+
+// Connect to the syncer and SyncableService specified.
+void GenericChangeProcessor::Connect(SyncableService* local_service,
+                                     sync_api::UserShare* user_share) {
+  AutoLock lock(monitor_lock_);
+  if (disconnected_)
+    return;
+  DCHECK(local_service);
+  local_service_ = local_service;
+  user_share_ = user_share;
+}
+
+void GenericChangeProcessor::Disconnect() {
+  VLOG(1) << "Disconnecting change processor.";
+  AutoLock lock(monitor_lock_);
+  disconnected_ = true;
 }
 
 void GenericChangeProcessor::ApplyChangesFromSyncModel(
     const sync_api::BaseTransaction* trans,
     const sync_api::ImmutableChangeRecordList& changes) {
   DCHECK(running());
   DCHECK(syncer_changes_.empty());
   for (sync_api::ChangeRecordList::const_iterator it =
            changes.Get().begin(); it != changes.Get().end(); ++it) {
     if (it->action == sync_api::ChangeRecord::ACTION_DELETE) {
@@ skipping 18 matching lines @@
     }
   }
 }
 
 void GenericChangeProcessor::CommitChangesFromSyncModel() {
   if (!running())
     return;
   if (syncer_changes_.empty())
     return;
   SyncError error = local_service_->ProcessSyncChanges(FROM_HERE,
-                                                        syncer_changes_);
+                                                       syncer_changes_);
   syncer_changes_.clear();
   if (error.IsSet()) {
     error_handler()->OnUnrecoverableError(error.location(), error.message());
   }
 }
 
 SyncError GenericChangeProcessor::GetSyncDataForType(
     syncable::ModelType type,
     SyncDataList* current_sync_data) {
+  AutoLock lock(monitor_lock_);
+  if (disconnected_) {
+    SyncError error(FROM_HERE, "Change processor disconnected.", type);
+    return error;
+  }
   std::string type_name = syncable::ModelTypeToString(type);
   sync_api::ReadTransaction trans(FROM_HERE, share_handle());
   sync_api::ReadNode root(&trans);
   if (!root.InitByTagLookup(syncable::ModelTypeToRootTag(type))) {
     SyncError error(FROM_HERE,
                     "Server did not create the top-level " + type_name +
                     " node. We might be running against an out-of-date server.",
                     type);
     return error;
   }
@@ skipping 37 matching lines @@
   }
   node->Remove();
   return true;
 }
 
 }  // namespace
 
 SyncError GenericChangeProcessor::ProcessSyncChanges(
     const tracked_objects::Location& from_here,
     const SyncChangeList& list_of_changes) {
+  AutoLock lock(monitor_lock_);
+  if (disconnected_) {
+    syncable::ModelType type;
+    if (list_of_changes.size() > 0) {
+      type = list_of_changes[0].sync_data().GetDataType();
+      local_service_->StopSyncing(type);
+    }
+    SyncError error(FROM_HERE, "Change processor disconnected.",
+                    syncable::UNSPECIFIED);
+    return error;
+  }
   sync_api::WriteTransaction trans(from_here, share_handle());
 
   for (SyncChangeList::const_iterator iter = list_of_changes.begin();
        iter != list_of_changes.end();
        ++iter) {
     const SyncChange& change = *iter;
     DCHECK_NE(change.sync_data().GetDataType(), syncable::UNSPECIFIED);
     syncable::ModelType type = change.sync_data().GetDataType();
     std::string type_str = syncable::ModelTypeToString(type);
     sync_api::WriteNode sync_node(&trans);
@@ skipping 59 matching lines @@
                                             error.message());
       return error;
     }
   }
   return SyncError();
 }
 
 bool GenericChangeProcessor::SyncModelHasUserCreatedNodes(
     syncable::ModelType type,
     bool* has_nodes) {
+  AutoLock lock(monitor_lock_);
+  if (disconnected_) {
+    LOG(ERROR) << "Change processor disconnected.";
+    return false;
+  }
   DCHECK(has_nodes);
   DCHECK_NE(type, syncable::UNSPECIFIED);
   std::string type_name = syncable::ModelTypeToString(type);
   std::string err_str = "Server did not create the top-level " + type_name +
       " node. We might be running against an out-of-date server.";
   *has_nodes = false;
   sync_api::ReadTransaction trans(FROM_HERE, share_handle());
   sync_api::ReadNode type_root_node(&trans);
   if (!type_root_node.InitByTagLookup(syncable::ModelTypeToRootTag(type))) {
     LOG(ERROR) << err_str;
     return false;
   }
 
   // The sync model has user created nodes if the type's root node has any
   // children.
   *has_nodes = sync_api::kInvalidId != type_root_node.GetFirstChildId();
   return true;
 }
 
 bool GenericChangeProcessor::CryptoReadyIfNecessary(syncable::ModelType type) {
+  AutoLock lock(monitor_lock_);
+  if (disconnected_) {
+    LOG(ERROR) << "Change processor disconnected.";
+    return true;  // Otherwise we get into infinite spin waiting.
+  }
   DCHECK_NE(type, syncable::UNSPECIFIED);
   // We only access the cryptographer while holding a transaction.
   sync_api::ReadTransaction trans(FROM_HERE, share_handle());
   const syncable::ModelTypeSet& encrypted_types =
       GetEncryptedTypes(&trans);
   return encrypted_types.count(type) == 0 ||
          trans.GetCryptographer()->is_ready();
 }
 
 void GenericChangeProcessor::StartImpl(Profile* profile) {}
 
-void GenericChangeProcessor::StopImpl() {}
+void GenericChangeProcessor::StopImpl() {
+  Disconnect();
+}
 
 sync_api::UserShare* GenericChangeProcessor::share_handle() {
   return user_share_;
 }
 
 }  // namespace browser_sync