blob: aee539167230b8198a97eeda534556a7fdd0868d [file] [log] [blame]
// Copyright (c) 2012 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 "base/files/file_path.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/lock.h"
#include "ipc/ipc_channel_proxy.h"
#include "ipc/ipc_sync_message_filter.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 {
// The |frame_routing_id| is the ID of the render_frame so that this class can
// send messages to the browser via that frame's route. The |plugin_child_id|
// is the ID in the browser process of the pepper plugin process host. We use
// this to identify the proper plugin process to terminate.
PepperHungPluginFilter(const base::FilePath& plugin_path,
int frame_routing_id,
int plugin_child_id);
// SyncMessageStatusReceiver implementation.
void BeginBlockOnSyncMessage() override;
void EndBlockOnSyncMessage() override;
// MessageFilter implementation.
void OnFilterRemoved() override;
void OnChannelError() override;
bool OnMessageReceived(const IPC::Message& message) override;
~PepperHungPluginFilter() override;
// 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_;
base::FilePath plugin_path_;
int frame_routing_id_;
int plugin_child_id_;
// Used to post messages to the renderer <-> browser message channel from
// other threads without having to worry about the lifetime of that object.
// We don't actually use the "sync" feature of this filter.
scoped_refptr<IPC::SyncMessageFilter> filter_;
scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
// 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_;
// 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_;
bool timer_task_pending_;
} // namespace content