content/renderer/pepper/pepper_hung_plugin_filter.h - chromium/src - Git at Google

 // Copyright 2012 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #ifndef CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_

 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "base/task/single_thread_task_runner.h"
 #include "base/time/time.h"
 #include "content/common/pepper_plugin.mojom.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_sync_message_filter.h"
 #include "mojo/public/cpp/bindings/pending_remote.h"
 #include "mojo/public/cpp/bindings/remote.h"
 #include "ppapi/proxy/host_dispatcher.h"

 namespace content {

 // This class monitors a renderer <-> pepper plugin channel on the I/O thread
 // of the renderer for a hung plugin.
 //
 // If the plugin is not responding to sync messages, it will notify the browser
 // process and give the user the option to kill the hung plugin.
 //
 // Note that this class must be threadsafe since it will get the begin/end
 // block notifications on the main thread, but the filter is run on the I/O
 // thread. This is important since when we're blocked on a sync message to a
 // hung plugin, the main thread is frozen.
 //
 // NOTE: This class is refcounted (via IPC::MessageFilter).
 class PepperHungPluginFilter
     : public ppapi::proxy::HostDispatcher::SyncMessageStatusObserver,
       public IPC::MessageFilter {
  public:
   PepperHungPluginFilter();

   PepperHungPluginFilter(const PepperHungPluginFilter&) = delete;
   PepperHungPluginFilter& operator=(const PepperHungPluginFilter&) = delete;

   // The |hung_host| is the mojo channel to inform the browser about the new
   // hung status.
   void BindHungDetectorHost(
       mojo::PendingRemote<mojom::PepperHungDetectorHost> hung_host);

   // SyncMessageStatusReceiver implementation.
   void BeginBlockOnSyncMessage() override;
   void EndBlockOnSyncMessage() override;

   // MessageFilter implementation.
   void OnFilterRemoved() override;
   void OnChannelError() override;
   bool OnMessageReceived(const IPC::Message& message) override;

   // Notification the HostDispatcher on the main thread has been destroyed.
   void HostDispatcherDestroyed();

  protected:
   ~PepperHungPluginFilter() override;

  private:
   // Binds the mojo channel on the IO thread (where it will be used).
   void BindHungDetectorHostOnIOThread(
       mojo::PendingRemote<mojom::PepperHungDetectorHost> hung_host);

   // Unbinds the mojo channel on the IO thread.
   void UnbindHungDetectorHostOnIOThread();

   // Makes sure that the hung timer is scheduled.
   void EnsureTimerScheduled();

   // Checks whether the plugin could have transitioned from hung to unhung and
   // notifies the browser if so.
   void MayHaveBecomeUnhung();

   // Calculate the point at which the plugin could next be considered hung.
   base::TimeTicks GetHungTime() const;

   // Checks if the plugin is considered hung based on whether it has been
   // blocked for long enough.
   bool IsHung() const;

   // Timer handler that checks for a hang after a timeout.
   void OnHangTimer();

   // Sends the hung/unhung message to the browser process.
   void SendHungMessage(bool is_hung);

   base::Lock lock_;

   scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;

   // The channel back to the browser for informing it of the new status.
   // This remote is bound and used on the IO thread.
   mojo::Remote<mojom::PepperHungDetectorHost> hung_host_;

   // The time when we start being blocked on a sync message. If there are
   // nested ones, this is the time of the outermost one.
   //
   // This will be is_null() if we've never blocked.
   base::TimeTicks began_blocking_time_;

   // Time that the last message was received from the plugin.
   //
   // This will be is_null() if we've never received any messages.
   base::TimeTicks last_message_received_;

   // Number of nested sync messages that we're blocked on.
   int pending_sync_message_count_ = 0;

   // True when we've sent the "plugin is hung" message to the browser. We track
   // this so we know to look for it becoming unhung and send the corresponding
   // message to the browser.
   bool hung_plugin_showing_ = false;

   bool timer_task_pending_ = false;
 };

 }  // namespace content

 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_
	// Copyright 2012 The Chromium Authors
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#ifndef CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_
	#define CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_

	#include "base/memory/ref_counted.h"
	#include "base/synchronization/lock.h"
	#include "base/task/single_thread_task_runner.h"
	#include "base/time/time.h"
	#include "content/common/pepper_plugin.mojom.h"
	#include "ipc/ipc_channel_proxy.h"
	#include "ipc/ipc_sync_message_filter.h"
	#include "mojo/public/cpp/bindings/pending_remote.h"
	#include "mojo/public/cpp/bindings/remote.h"
	#include "ppapi/proxy/host_dispatcher.h"

	namespace content {

	// This class monitors a renderer <-> pepper plugin channel on the I/O thread
	// of the renderer for a hung plugin.
	//
	// If the plugin is not responding to sync messages, it will notify the browser
	// process and give the user the option to kill the hung plugin.
	//
	// Note that this class must be threadsafe since it will get the begin/end
	// block notifications on the main thread, but the filter is run on the I/O
	// thread. This is important since when we're blocked on a sync message to a
	// hung plugin, the main thread is frozen.
	//
	// NOTE: This class is refcounted (via IPC::MessageFilter).
	class PepperHungPluginFilter
	: public ppapi::proxy::HostDispatcher::SyncMessageStatusObserver,
	public IPC::MessageFilter {
	public:
	PepperHungPluginFilter();

	PepperHungPluginFilter(const PepperHungPluginFilter&) = delete;
	PepperHungPluginFilter& operator=(const PepperHungPluginFilter&) = delete;

	// The \|hung_host\| is the mojo channel to inform the browser about the new
	// hung status.
	void BindHungDetectorHost(
	mojo::PendingRemote<mojom::PepperHungDetectorHost> hung_host);

	// SyncMessageStatusReceiver implementation.
	void BeginBlockOnSyncMessage() override;
	void EndBlockOnSyncMessage() override;

	// MessageFilter implementation.
	void OnFilterRemoved() override;
	void OnChannelError() override;
	bool OnMessageReceived(const IPC::Message& message) override;

	// Notification the HostDispatcher on the main thread has been destroyed.
	void HostDispatcherDestroyed();

	protected:
	~PepperHungPluginFilter() override;

	private:
	// Binds the mojo channel on the IO thread (where it will be used).
	void BindHungDetectorHostOnIOThread(
	mojo::PendingRemote<mojom::PepperHungDetectorHost> hung_host);

	// Unbinds the mojo channel on the IO thread.
	void UnbindHungDetectorHostOnIOThread();

	// Makes sure that the hung timer is scheduled.
	void EnsureTimerScheduled();

	// Checks whether the plugin could have transitioned from hung to unhung and
	// notifies the browser if so.
	void MayHaveBecomeUnhung();

	// Calculate the point at which the plugin could next be considered hung.
	base::TimeTicks GetHungTime() const;

	// Checks if the plugin is considered hung based on whether it has been
	// blocked for long enough.
	bool IsHung() const;

	// Timer handler that checks for a hang after a timeout.
	void OnHangTimer();

	// Sends the hung/unhung message to the browser process.
	void SendHungMessage(bool is_hung);

	base::Lock lock_;

	scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;

	// The channel back to the browser for informing it of the new status.
	// This remote is bound and used on the IO thread.
	mojo::Remote<mojom::PepperHungDetectorHost> hung_host_;

	// The time when we start being blocked on a sync message. If there are
	// nested ones, this is the time of the outermost one.
	//
	// This will be is_null() if we've never blocked.
	base::TimeTicks began_blocking_time_;

	// Time that the last message was received from the plugin.
	//
	// This will be is_null() if we've never received any messages.
	base::TimeTicks last_message_received_;

	// Number of nested sync messages that we're blocked on.
	int pending_sync_message_count_ = 0;

	// True when we've sent the "plugin is hung" message to the browser. We track
	// this so we know to look for it becoming unhung and send the corresponding
	// message to the browser.
	bool hung_plugin_showing_ = false;

	bool timer_task_pending_ = false;
	};

	} // namespace content

	#endif // CONTENT_RENDERER_PEPPER_PEPPER_HUNG_PLUGIN_FILTER_H_