Adds the UserInputMonitor implementation for Mac.

media/base/user_input_monitor_mac.cc

+// Copyright 2013 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 "media/base/user_input_monitor.h"
+
+#include <ApplicationServices/ApplicationServices.h>
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/mac/scoped_cftyperef.h"
+#include "base/message_loop/message_loop.h"
+#include "base/single_thread_task_runner.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "third_party/skia/include/core/SkPoint.h"
+
+namespace media {
+namespace {
+
+class UserInputMonitorMacCore;
+
+class UserInputMonitorMac : public UserInputMonitor {
+ public:
+  typedef const base::Callback<void(const SkIPoint&)> MouseCallback;
+
+  UserInputMonitorMac(
+      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
+
+  virtual ~UserInputMonitorMac();
+
+ private:
+  virtual void StartMouseMonitoring() OVERRIDE;
+  virtual void StopMouseMonitoring() OVERRIDE;
+  virtual void StartKeyboardMonitoring() OVERRIDE;
+  virtual void StopKeyboardMonitoring() OVERRIDE;
+
+  void OnMouseMoved(const SkIPoint& position);
+  void OnKeyStroke();
+
+  // Task runner on which input events are received.
+  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
+
+  scoped_ptr<UserInputMonitorMacCore> core_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserInputMonitorMac);
+};
+
+// The class implements the event listening. Must be called on the UI thread.
+class UserInputMonitorMacCore {
+ public:
+  UserInputMonitorMacCore(
+      const UserInputMonitorMac::MouseCallback& mouse_callback,
+      const base::Closure& key_stroke_callback);
+  ~UserInputMonitorMacCore();
+
+  void StartMonitoringMouse();
+  void StopMonitoringMouse();
+  void StartPollingKeyState();
+  void StopPollingKeyState();
+
+  void OnMouseMoved(const SkIPoint& position);
+
+  base::WeakPtr<UserInputMonitorMacCore> GetAsWeakPtr();
+
+ private:
+  static CGEventRef MouseMoved(CGEventTapProxy proxy,
+                               CGEventType type,
+                               CGEventRef event,
+                               void* context);
+  void PollKeyState();
+
+  UserInputMonitorMac::MouseCallback mouse_callback_;
+  base::Closure key_stroke_callback_;
+
+  base::ScopedCFTypeRef<CFRunLoopSourceRef> input_run_loop_source_;
+  base::ScopedCFTypeRef<CFMachPortRef> input_mach_port_;
+
+  base::Timer polling_timer_;
+  // 0x5c is key "9", after that comes function keys.
+  bool prev_key_state_[0x5d];
+
+  base::WeakPtrFactory<UserInputMonitorMacCore> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserInputMonitorMacCore);
+};
+
+UserInputMonitorMac::UserInputMonitorMac(
+    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner)
+    : ui_task_runner_(ui_task_runner),
+      core_(new UserInputMonitorMacCore(
+          base::Bind(&UserInputMonitorMac::OnMouseMoved,
+                     base::Unretained(this)),
+          base::Bind(&UserInputMonitorMac::OnKeyStroke,
+                     base::Unretained(this)))) {}
+
+UserInputMonitorMac::~UserInputMonitorMac() {
+  ui_task_runner_->DeleteSoon(FROM_HERE, core_.release());
+}
+
+void UserInputMonitorMac::StartMouseMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMacCore::StartMonitoringMouse,
+                   core_->GetAsWeakPtr()));
+    return;
+  }
+  core_->StartMonitoringMouse();
+}
+
+void UserInputMonitorMac::StopMouseMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMacCore::StopMonitoringMouse,
+                   core_->GetAsWeakPtr()));
+    return;
+  }
+  core_->StopMonitoringMouse();
+}
+
+void UserInputMonitorMac::StartKeyboardMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMacCore::StartPollingKeyState,
+                   core_->GetAsWeakPtr()));
+    return;
+  }
+  core_->StartPollingKeyState();
+}
+
+void UserInputMonitorMac::StopKeyboardMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMacCore::StopPollingKeyState,
+                   core_->GetAsWeakPtr()));
+    return;
+  }
+  core_->StopPollingKeyState();
+}
+
+void UserInputMonitorMac::OnMouseMoved(const SkIPoint& position) {
+  UserInputMonitor::OnMouseEvent(position);
+}
+
+void UserInputMonitorMac::OnKeyStroke() {
+  UserInputMonitor::OnKeyboardEvent(ui::ET_KEY_PRESSED, ui::VKEY_UNKNOWN);
+}
+
+UserInputMonitorMacCore::UserInputMonitorMacCore(
+    const UserInputMonitorMac::MouseCallback& mouse_callback,
+    const base::Closure& key_stroke_callback)
+    : mouse_callback_(mouse_callback),
+      key_stroke_callback_(key_stroke_callback),
+      polling_timer_(false, true),
+      weak_factory_(this) {}
+
+UserInputMonitorMacCore::~UserInputMonitorMacCore() {
+  DCHECK(!input_mach_port_);
+  DCHECK(!input_run_loop_source_);
+  DCHECK(!polling_timer_.IsRunning());
+}
+
+void UserInputMonitorMacCore::StartMonitoringMouse() {
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
+
+  input_mach_port_.reset(CGEventTapCreate(kCGSessionEventTap,
+                                          kCGHeadInsertEventTap,
+                                          kCGEventTapOptionListenOnly,
+                                          CGEventMaskBit(kCGEventMouseMoved),
+                                          MouseMoved,
+                                          this));
+  if (input_mach_port_) {
+    input_run_loop_source_.reset(
+        CFMachPortCreateRunLoopSource(NULL, input_mach_port_, 0));
+    CFRunLoopAddSource(
+        CFRunLoopGetMain(), input_run_loop_source_, kCFRunLoopCommonModes);
+  } else {
+    LOG(ERROR) << "CGEventTapCreate failed.";
+  }
+}
+
+void UserInputMonitorMacCore::StopMonitoringMouse() {
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
+
+  if (input_run_loop_source_) {
+    CFMachPortInvalidate(input_mach_port_);
+    CFRunLoopRemoveSource(
+        CFRunLoopGetMain(), input_run_loop_source_, kCFRunLoopCommonModes);
+    input_run_loop_source_.reset();
+    input_mach_port_.reset();
+  }
+}
+
+void UserInputMonitorMacCore::StartPollingKeyState() {
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
+
+  polling_timer_.Start(
+      FROM_HERE,
+      base::TimeDelta::FromMilliseconds(30),
+      base::Bind(&UserInputMonitorMacCore::PollKeyState, GetAsWeakPtr()));
+}
+
+void UserInputMonitorMacCore::StopPollingKeyState() {
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
+
+  polling_timer_.Stop();
+}
+
+base::WeakPtr<UserInputMonitorMacCore> UserInputMonitorMacCore::GetAsWeakPtr() {
+  return weak_factory_.GetWeakPtr();
+}
+
+void UserInputMonitorMacCore::OnMouseMoved(const SkIPoint& position) {
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
+
+  mouse_callback_.Run(position);
+}
+
+CGEventRef UserInputMonitorMacCore::MouseMoved(CGEventTapProxy proxy,
+                                               CGEventType type,
+                                               CGEventRef event,
+                                               void* context) {
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
+
+  int64_t pid = CGEventGetIntegerValueField(event, kCGEventSourceUnixProcessID);
+  // |pid| 0 means the event is generated by hardware.
+  if (pid == 0) {
+    DCHECK_EQ(kCGEventMouseMoved, type);
+    CGPoint cg_mouse_pos = CGEventGetLocation(event);
+    SkIPoint mouse_pos = SkIPoint::Make(cg_mouse_pos.x, cg_mouse_pos.y);
+    static_cast<UserInputMonitorMacCore*>(context)->OnMouseMoved(mouse_pos);
+  }
+  return NULL;
+}
+
+void UserInputMonitorMacCore::PollKeyState() {
+  DCHECK_EQ(base::MessageLoop::TYPE_UI, base::MessageLoop::current()->type());
+
+  bool key_pressed = false;
+  for (CGKeyCode key_index = 0; key_index < arraysize(prev_key_state_);
+       ++key_index) {
+    bool key_state =
+        CGEventSourceKeyState(kCGEventSourceStateHIDSystemState, key_index);

[Wez, 2013/08/21 22:41:57]

This should be *SessionState, not *SystemState, I think.

[jiayl, 2013/08/21 22:58:23]

The webrtc impl uses *SystemState:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/webrtc...

We should only care about hardware events.

[Wez, 2013/08/21 23:19:53]

Monitoring session events is correct in terms of scope - if the user session is
switched out then you don't want to be monitoring the console keyboard for
events - and non-hardware keyboard events are probably not common enough for
capturing them as well to be a problem, surely?

[jiayl, 2013/08/21 23:32:59]

I'm not sure. What's the state of audio capturing when a user session is
switched out? If it's still capturing, we should keep monitoring the keyboard. 
I tried locking my workstation while in a video call and audio/video was still
being recorded.

+    // A false -> true change in keymap means a key is pressed.
+    key_pressed |= (key_state && !prev_key_state_[key_index]);
+    // Save current state.
+    prev_key_state_[key_index] = key_state;
+  }
+
+  if (key_pressed)
+    key_stroke_callback_.Run();
+}
+
+}  // namespace
+
+scoped_ptr<UserInputMonitor> UserInputMonitor::Create(
+    const scoped_refptr<base::SingleThreadTaskRunner>& input_task_runner,
+    const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner) {
+  return scoped_ptr<UserInputMonitor>(new UserInputMonitorMac(ui_task_runner));
+}
+
+}  // namespace media