Add a NotificationTemplateBuilder for Action Center toasts

chrome/browser/notifications/notification_template_builder.cc

+// Copyright 2017 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/notifications/notification_template_builder.h"
+
+#include "base/memory/ptr_util.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "components/url_formatter/elide_url.h"
+#include "third_party/libxml/chromium/libxml_utils.h"
+#include "ui/message_center/notification.h"
+#include "url/origin.h"
+
+namespace {
+
+// Constants used for the XML element names and their attributes.
+const char kToastElement[] = "toast";
+const char kToastElementLaunchAttribute[] = "launch";
+const char kVisualElement[] = "visual";
+const char kBindingElement[] = "binding";
+const char kBindingElementTemplateAttribute[] = "template";
+const char kTextElement[] = "text";
+const char kTextElementIdAttribute[] = "id";
+
+// Name of the template used for default Chrome notifications.
+// https://msdn.microsoft.com/library/1a437614-4259-426b-8e3f-ca57368b2e7a
+const char kDefaultTemplate[] = "ToastText04";
+
+// The XML version header that has to be stripped from the output.
+const char kXmlVersionHeader[] = "<?xml version=\"1.0\"?>\n";
+
+}  // namespace
+
+// static
+std::unique_ptr<NotificationTemplateBuilder> NotificationTemplateBuilder::Build(
+    const std::string& notification_id,
+    const message_center::Notification& notification) {
+  std::unique_ptr<NotificationTemplateBuilder> builder =
+      base::WrapUnique(new NotificationTemplateBuilder);
+
+  // TODO(finnur): Can we set <toast scenario="reminder"> for notifications
+  // that have set the never_timeout() flag?
+  builder->StartToastElement(notification_id);
+  builder->StartVisualElement();
+
+  // TODO(finnur): Set the correct binding template based on the |notification|.
+  builder->StartBindingElement(kDefaultTemplate);
+
+  // Content for the ToastText04 toast template.
+  // https://msdn.microsoft.com/library/1a437614-4259-426b-8e3f-ca57368b2e7a#ToastText04
+  builder->WriteTextElement("1", base::UTF16ToUTF8(notification.title()));
+  builder->WriteTextElement("2", base::UTF16ToUTF8(notification.message()));
+  builder->WriteTextElement("3",
+                            builder->FormatOrigin(notification.origin_url()));
+
+  builder->EndBindingElement();
+
+  builder->EndVisualElement();
+  builder->EndToastElement();

[Peter Beverloo, 2017/06/05 17:06:25]

An alternative would be to use comments:

builder->EndElement();  // </toast>

[Finnur, 2017/06/06 11:00:09]

EndToastElement(), you mean?

I don't know... Seems simple enough without it. 

[Peter Beverloo, 2017/06/16 15:40:21]

OK, we'll leave as is, this is super simple to change later on when we have a
better idea of how the builder is going to work for more complex layouts.

+
+  return builder;
+}
+
+NotificationTemplateBuilder::NotificationTemplateBuilder()
+    : xml_writer_(base::MakeUnique<XmlWriter>()) {
+  xml_writer_->StartWriting();
+}
+
+NotificationTemplateBuilder::~NotificationTemplateBuilder() = default;
+
+std::string NotificationTemplateBuilder::GetNotificationTemplate() {
+  std::string template_xml = xml_writer_->GetWrittenString();
+  DCHECK(base::StartsWith(template_xml, kXmlVersionHeader,
+                          base::CompareCase::SENSITIVE));
+
+  // The |kXmlVersionHeader| is automatically appended by libxml, but the toast
+  // systen in the Windows Action Center expects it to be absent.
+  return template_xml.substr(sizeof(kXmlVersionHeader) - 1);

[Peter Beverloo, 2017/06/05 17:06:25]

:(

+}
+
+std::string NotificationTemplateBuilder::FormatOrigin(
+    const GURL& origin) const {
+  base::string16 origin_string = url_formatter::FormatOriginForSecurityDisplay(
+      url::Origin(origin), url_formatter::SchemeDisplay::OMIT_HTTP_AND_HTTPS);
+  DCHECK(origin_string.size());
+
+  return base::UTF16ToUTF8(origin_string);
+}
+
+void NotificationTemplateBuilder::StartToastElement(
+    const std::string& notification_id) {
+  xml_writer_->StartElement(kToastElement);
+  xml_writer_->AddAttribute(kToastElementLaunchAttribute, notification_id);
+}
+
+void NotificationTemplateBuilder::EndToastElement() {
+  xml_writer_->EndElement();
+  xml_writer_->StopWriting();
+}
+
+void NotificationTemplateBuilder::StartVisualElement() {
+  xml_writer_->StartElement(kVisualElement);
+}
+
+void NotificationTemplateBuilder::EndVisualElement() {
+  xml_writer_->EndElement();
+}
+
+void NotificationTemplateBuilder::StartBindingElement(
+    const std::string& template_name) {
+  xml_writer_->StartElement(kBindingElement);
+  xml_writer_->AddAttribute(kBindingElementTemplateAttribute, template_name);
+}
+
+void NotificationTemplateBuilder::EndBindingElement() {
+  xml_writer_->EndElement();
+}
+
+void NotificationTemplateBuilder::WriteTextElement(const std::string& id,
+                                                   const std::string& content) {
+  xml_writer_->StartElement(kTextElement);
+  xml_writer_->AddAttribute(kTextElementIdAttribute, id);
+  xml_writer_->AppendElementContent(content);
+  xml_writer_->EndElement();
+}