Refactor NotificationPlatformBridgeLinux

chrome/browser/notifications/notification_platform_bridge_linux.h

 // 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.
 
 #ifndef CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_PLATFORM_BRIDGE_LINUX_H_
 #define CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_PLATFORM_BRIDGE_LINUX_H_
 
-#include <gio/gio.h>
-
 #include <unordered_map>
 
 #include "base/macros.h"
-#include "base/memory/weak_ptr.h"
 #include "chrome/browser/notifications/notification_platform_bridge.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-#include "ui/base/glib/glib_signal.h"
-#include "ui/base/glib/scoped_gobject.h"
 
-class NotificationPlatformBridgeLinux : public NotificationPlatformBridge,
-                                        public content::NotificationObserver {
+class NotificationPlatformBridgeLinux : public NotificationPlatformBridge {
  public:
-  explicit NotificationPlatformBridgeLinux(GDBusProxy* notification_proxy);
+  NotificationPlatformBridgeLinux();
 
   ~NotificationPlatformBridgeLinux() override;
 
   // NotificationPlatformBridge:
   void Display(NotificationCommon::Type notification_type,
                const std::string& notification_id,
                const std::string& profile_id,
                bool is_incognito,
                const Notification& notification) override;
   void Close(const std::string& profile_id,
              const std::string& notification_id) override;
   void GetDisplayed(
       const std::string& profile_id,
       bool incognito,
       const DisplayedNotificationsCallback& callback) const override;
 
-  // Called from NotifyCompleteReceiver().
-  void NotifyCompleteInternal(gpointer user_data, GVariant* value);
+  // Waits until the D-Bus connection has been created.  Returns true
+  // if the connection was successful.
+  bool BlockUntilReady();
 
  private:
-  struct NotificationData;
-  struct ResourceFiles;
+  class NativeNotificationThread;
 
-  // content::NotificationObserver:
-  void Observe(int type,
-               const content::NotificationSource& source,
-               const content::NotificationDetails& details) override;
-
-  // Sets up a task to call NotifyNow() after an IO thread writes the
-  // necessary resource files.
-  void Notify(const Notification& notification,
-              NotificationData* data,
-              GAsyncReadyCallback callback,
-              gpointer user_data);
-
-  // Makes the "Notify" call to D-Bus.
-  void NotifyNow(const Notification& notification,
-                 base::WeakPtr<NotificationData> data,
-                 GAsyncReadyCallback callback,
-                 gpointer user_data,
-                 std::unique_ptr<ResourceFiles> resource_files);
-
-  // Makes the "CloseNotification" call to D-Bus.
-  void CloseNow(uint32_t dbus_id);
-
-  void ForwardNotificationOperation(uint32_t dbus_id,
-                                    NotificationCommon::Operation operation,
-                                    int action_index);
-
-  // GSignalReceiver: The function that GLib calls into for
-  // ActionInvoked and NotificationClosed signals.
-  CHROMEG_CALLBACK_3(NotificationPlatformBridgeLinux,
-                     void,
-                     GSignalReceiver,
-                     GDBusProxy*,
-                     const char*,
-                     const char*,
-                     GVariant*);
-
-  NotificationData* FindNotificationData(const std::string& notification_id,
-                                         const std::string& profile_id,
-                                         bool is_incognito);
-
-  NotificationData* FindNotificationData(uint32_t dbus_id);
-
-  ScopedGObject<GDBusProxy> notification_proxy_;
-
-  // Used to disconnect from "g-signal" during destruction.
-  gulong proxy_signal_handler_ = 0;
-
-  // A std::set<std::unique_ptr<T>> doesn't work well because
-  // eg. std::set::erase(T) would require a std::unique_ptr<T>
-  // argument, so the data would get double-destructed.
-  template <typename T>
-  using UnorderedUniqueSet = std::unordered_map<T*, std::unique_ptr<T>>;
-
-  UnorderedUniqueSet<NotificationData> notifications_;
-
-  content::NotificationRegistrar registrar_;
-
-  base::WeakPtrFactory<NotificationPlatformBridgeLinux> weak_factory_;
+  std::unique_ptr<NativeNotificationThread> thread_;

[Lei Zhang, 2017/04/17 23:32:14]

Is there an easy way to reuse an existing thread? We want to to avoid creating
too many threads (there are too many threads!) when possible.

e.g. device/power_save_blocker/power_save_blocker_x11.cc accesses DBus and it
uses
content::BrowserThread::GetTaskRunnerForThread(content::BrowserThread::FILE) for
its |blocking_task_runner_| most of the time.

[Tom (Use chromium acct), 2017/04/18 01:41:11]

Create() needs to block, so I'm reluctant to put this on the file thread, since
there could already be a bunch of tasks queued up which the UI thread would then
have to wait for.

But there _is_ a way to do this w/o blocking at all.

* NPBL could queue up Display()/Close()/GetDisplayed() while the Dbus connection
initializes. 
* Then if we find out the system supports notifications, post all of the queued
up tasks to the notification thread
* If it turns out the system doesn't support notifications, create a
MessageCenterDisplayService on that on the current (UI) thread
* After this point, just post/run the callback and skip the queuing

We could also post to the file thread if we do this.  thestig@ wdyt?

[Lei Zhang, 2017/04/18 02:39:58]

Yes, that sounds like how many other DBus clients work. I didn't look hard
enough and just noticed the OnConnectedCallback to ConnectToSignal() is just a
DCHECK. :-|

 
   DISALLOW_COPY_AND_ASSIGN(NotificationPlatformBridgeLinux);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_PLATFORM_BRIDGE_LINUX_H_