[Sync] Move some code into new class JsMutationEventObserver

chrome/browser/sync/js/js_mutation_event_observer.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/js/js_mutation_event_observer.h"
+
+#include <string>
+
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/string_number_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/sync/js/js_event_details.h"
+#include "chrome/browser/sync/js/js_event_handler.h"
+
+namespace browser_sync {
+
+JsMutationEventObserver::JsMutationEventObserver() {}
+
+JsMutationEventObserver::~JsMutationEventObserver() {
+  DCHECK(non_thread_safe_.CalledOnValidThread());
+}
+
+void JsMutationEventObserver::SetJsEventHandler(
+    const WeakHandle<JsEventHandler>& event_handler) {
+  event_handler_ = event_handler;
+}
+
+void JsMutationEventObserver::OnTransactionStart(
+    const tracked_objects::Location& location,
+    const syncable::WriterTag& writer) {
+  DCHECK(non_thread_safe_.CalledOnValidThread());
+  if (!event_handler_.IsInitialized()) {
+    return;
+  }
+  DictionaryValue details;
+  details.SetString("location", location.ToString());
+  details.SetString("writer", syncable::WriterTagToString(writer));
+  HandleJsEvent(FROM_HERE, "onTransactionStart", JsEventDetails(&details));
+}
+
+namespace {
+
+// Max number of changes we attempt to convert to values (to avoid
+// running out of memory).
+const size_t kChangeLimit = 100;
+
+}  // namespace
+
+void JsMutationEventObserver::OnChangesApplied(
+    syncable::ModelType model_type,
+    int64 write_transaction_id,
+    const sync_api::ImmutableChangeRecordList& changes) {
+  if (!event_handler_.IsInitialized()) {
+    return;
+  }
+  DictionaryValue details;
+  details.SetString("modelType", syncable::ModelTypeToString(model_type));
+  details.SetString("writeTransactionId",
+                    base::Int64ToString(write_transaction_id));
+  base::Value* changes_value = NULL;
+  const size_t changes_size = changes.Get().size();
+  if (changes_size <= kChangeLimit) {
+    ListValue* changes_list = new ListValue();
+    for (sync_api::ChangeRecordList::const_iterator it =
+             changes.Get().begin(); it != changes.Get().end(); ++it) {
+      changes_list->Append(it->ToValue());
+    }
+    changes_value = changes_list;
+  } else {
+    changes_value =
+        Value::CreateStringValue(
+            base::Uint64ToString(static_cast<uint64>(changes_size)) +
+            " changes");
+  }
+  details.Set("changes", changes_value);
+  HandleJsEvent(FROM_HERE, "onChangesApplied", JsEventDetails(&details));
+}
+
+void JsMutationEventObserver::OnChangesComplete(
+    syncable::ModelType model_type) {
+  if (!event_handler_.IsInitialized()) {
+    return;
+  }
+  DictionaryValue details;
+  details.SetString("modelType", syncable::ModelTypeToString(model_type));
+  HandleJsEvent(FROM_HERE, "onChangesComplete", JsEventDetails(&details));
+}
+
+void JsMutationEventObserver::OnTransactionWrite(
+    const syncable::ImmutableWriteTransactionInfo& write_transaction_info,
+    const syncable::ModelTypeBitSet& models_with_changes) {
+  DCHECK(non_thread_safe_.CalledOnValidThread());
+  if (!event_handler_.IsInitialized()) {
+    return;
+  }
+  DictionaryValue details;
+  details.Set("writeTransactionInfo",
+              write_transaction_info.Get().ToValue(kChangeLimit));
+  details.Set("modelsWithChanges",
+              syncable::ModelTypeBitSetToValue(models_with_changes));
+  HandleJsEvent(FROM_HERE, "onTransactionWrite", JsEventDetails(&details));
+}
+
+void JsMutationEventObserver::OnTransactionEnd(
+    const tracked_objects::Location& location,
+    const syncable::WriterTag& writer) {
+  DCHECK(non_thread_safe_.CalledOnValidThread());
+  if (!event_handler_.IsInitialized()) {
+    return;
+  }
+  DictionaryValue details;
+  details.SetString("location", location.ToString());
+  details.SetString("writer", syncable::WriterTagToString(writer));
+  HandleJsEvent(FROM_HERE, "onTransactionEnd", JsEventDetails(&details));
+}
+
+void JsMutationEventObserver::HandleJsEvent(
+    const tracked_objects::Location& from_here,
+    const std::string& name, const JsEventDetails& details) {
+  if (!event_handler_.IsInitialized()) {
+    NOTREACHED();
+    return;
+  }
+  event_handler_.Call(from_here,
+                      &JsEventHandler::HandleJsEvent, name, details);
+}
+
+}  // namespace browser_sync