Make MediaInternalsUI talk to MediaInternals.

chrome/browser/ui/webui/media_internals_ui.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/ui/webui/media_internals_ui.h"
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/values.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/io_thread.h"
+#include "chrome/browser/media/media_internals.h"
+#include "chrome/browser/media/media_internals_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/browser/ui/webui/chrome_url_data_manager.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/url_constants.h"
+#include "content/browser/renderer_host/render_view_host.h"
 #include "grit/browser_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 
 namespace {
 
+class MediaInternalsProxy;
+
 class MediaInternalsHTMLSource : public ChromeURLDataManager::DataSource {
  public:
   MediaInternalsHTMLSource();
 
   // Called when the network layer has requested a resource underneath
   // the path we registered.
   virtual void StartDataRequest(const std::string& path,
                                 bool is_incognito,
                                 int request_id);
   virtual std::string GetMimeType(const std::string& path) const;
 
  private:
   virtual ~MediaInternalsHTMLSource() {}
   DISALLOW_COPY_AND_ASSIGN(MediaInternalsHTMLSource);
 };
 
+// This class handles messages to and from MediaInternalsUI.
+// It does all its work on the IO thread through the proxy below.
+class MediaInternalsMessageHandler : public WebUIMessageHandler {

[Evan Stade, 2011/06/30 22:24:27]

please do break this into a separate file. net_internals_ui sets a bad precedent
that should not be followed.

since you will have 6 files now instead of 2, I think it's a good idea to give
media_internals its own directory.

[Scott Franklin, 2011/07/01 01:42:32]

Alright, split and filed (directoried?). I'm assuming breaking off the
HTMLSource would be considered overkill.

It is nice when entire files fit on one screen.

+ public:
+  MediaInternalsMessageHandler();
+  virtual ~MediaInternalsMessageHandler();
+
+  // WebUIMessageHandler implementation.
+  virtual WebUIMessageHandler* Attach(WebUI* web_ui);
+  virtual void RegisterMessages();
+
+  // Javascript message handlers.
+  void OnGetEverything(const ListValue* list);
+
+  // MediaInternals message handlers.
+  void OnUpdate(const string16& update);
+
+ private:
+  scoped_refptr<MediaInternalsProxy> proxy_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaInternalsMessageHandler);
+};
+
+// This class is a proxy between MediaInternals (on the IO thread) and
+// MediaInternalsMessageHandler (on the UI thread).
+// It is ref_counted to ensure that it completes all pending Tasks on both
+// threads before destruction.
+class MediaInternalsProxy
+    : public MediaInternalsObserver,
+      public base::RefCountedThreadSafe<MediaInternalsProxy> {
+ public:
+  MediaInternalsProxy();
+
+  // Register a Handler and start receiving callbacks from MediaInternals.
+  void Attach(MediaInternalsMessageHandler* handler);
+
+  // Unregister the same and stop receiving callbacks.
+  void Detach();
+
+  // Have MediaInternals send all the data it has.
+  void GetEverything();
+
+  // MediaInternalsObserver implementation. Called on the IO thread.
+  virtual void OnUpdate(const string16& update);
+
+ private:
+  friend class base::RefCountedThreadSafe<MediaInternalsProxy>;
+  virtual ~MediaInternalsProxy();
+
+  void ObserveMediaInternalsOnIOThread();
+  void StopObservingMediaInternalsOnIOThread();
+  void GetEverythingOnIOThread();
+  void UpdateUIOnUIThread(const string16& update);
+
+  MediaInternalsMessageHandler* handler_;
+  IOThread* io_thread_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaInternalsProxy);
+};
+
 ////////////////////////////////////////////////////////////////////////////////
 //
 // MediaInternalsHTMLSource
 //
 ////////////////////////////////////////////////////////////////////////////////
 
 MediaInternalsHTMLSource::MediaInternalsHTMLSource()
     : DataSource(chrome::kChromeUIMediaInternalsHost, MessageLoop::current()) {
 }
 
@@ skipping 17 matching lines @@
   std::copy(html.begin(), html.end(), bytes->data.begin());
 
   SendResponse(request_id, bytes);
 }
 
 std::string MediaInternalsHTMLSource::GetMimeType(
     const std::string& path) const {
   return "text/html";
 }
 
-} // namespace
+////////////////////////////////////////////////////////////////////////////////
+//
+// MediaInternalsMessageHandler
+//
+////////////////////////////////////////////////////////////////////////////////
 
+MediaInternalsMessageHandler::MediaInternalsMessageHandler()
+    : proxy_(new MediaInternalsProxy()) {}
+
+MediaInternalsMessageHandler::~MediaInternalsMessageHandler() {
+  proxy_->Detach();
+}
+
+WebUIMessageHandler* MediaInternalsMessageHandler::Attach(WebUI* web_ui) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  WebUIMessageHandler* result = WebUIMessageHandler::Attach(web_ui);
+  proxy_->Attach(this);
+  return result;
+}
+
+void MediaInternalsMessageHandler::RegisterMessages() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  web_ui_->RegisterMessageCallback(
+      "getEverything",
+      NewCallback(this, &MediaInternalsMessageHandler::OnGetEverything));
+}
+
+void MediaInternalsMessageHandler::OnGetEverything(const ListValue* list) {
+  proxy_->GetEverything();
+}
+
+void MediaInternalsMessageHandler::OnUpdate(const string16& update) {
+  web_ui_->GetRenderViewHost()->ExecuteJavascriptInWebFrame(string16(), update);
+}
 
 ////////////////////////////////////////////////////////////////////////////////
 //
+// MediaInternalsProxy
+//
+////////////////////////////////////////////////////////////////////////////////
+
+MediaInternalsProxy::MediaInternalsProxy() {
+  io_thread_ = g_browser_process->io_thread();
+}
+
+void MediaInternalsProxy::Attach(MediaInternalsMessageHandler* handler) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  handler_ = handler;
+  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this,
+          &MediaInternalsProxy::ObserveMediaInternalsOnIOThread));
+}
+
+void MediaInternalsProxy::Detach() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  handler_ = NULL;
+  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this,
+          &MediaInternalsProxy::StopObservingMediaInternalsOnIOThread));
+}
+
+void MediaInternalsProxy::GetEverything() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this, &MediaInternalsProxy::GetEverythingOnIOThread));
+}
+
+void MediaInternalsProxy::OnUpdate(const string16& update) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+      NewRunnableMethod(this,
+          &MediaInternalsProxy::UpdateUIOnUIThread, update));
+}
+
+MediaInternalsProxy::~MediaInternalsProxy() {}
+
+void MediaInternalsProxy::ObserveMediaInternalsOnIOThread() {
+  io_thread_->globals()->media.media_internals->AddUI(this);
+}
+
+void MediaInternalsProxy::StopObservingMediaInternalsOnIOThread() {
+  io_thread_->globals()->media.media_internals->RemoveUI(this);
+}
+
+void MediaInternalsProxy::GetEverythingOnIOThread() {
+  io_thread_->globals()->media.media_internals->SendEverything();
+}
+
+void MediaInternalsProxy::UpdateUIOnUIThread(const string16& update) {
+  // Don't forward updates to a destructed UI.
+  if (handler_)
+    handler_->OnUpdate(update);
+}
+
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+//
 // MediaInternalsUI
 //
 ////////////////////////////////////////////////////////////////////////////////
 
 MediaInternalsUI::MediaInternalsUI(TabContents* contents)
     : ChromeWebUI(contents) {
+  AddMessageHandler((new MediaInternalsMessageHandler())->Attach(this));
+
   contents->profile()->GetChromeURLDataManager()->AddDataSource(
       new MediaInternalsHTMLSource());
 }
-