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 UserInputMonitorMac : public UserInputMonitor {
+ public:
+  explicit UserInputMonitorMac(
+      scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
+  virtual ~UserInputMonitorMac();
+
+ private:
+  static CGEventRef MouseMoved(CGEventTapProxy proxy,
+                               CGEventType type,
+                               CGEventRef event,
+                               void* context);
+
+  virtual void StartMouseMonitoring() OVERRIDE;
+  virtual void StopMouseMonitoring() OVERRIDE;
+  virtual void StartKeyboardMonitoring() OVERRIDE;
+  virtual void StopKeyboardMonitoring() OVERRIDE;
+
+  void PollKeyState();
+
+  // Task runner on which input events are received.
+  scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
+
+  // These members should only be accessed on the UI thread.
+  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];
+
+  DISALLOW_COPY_AND_ASSIGN(UserInputMonitorMac);
+};
+
+UserInputMonitorMac::UserInputMonitorMac(
+    scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner)
+    : ui_task_runner_(ui_task_runner),
+      polling_timer_(false, true) {}
+
+UserInputMonitorMac::~UserInputMonitorMac() {
+  DCHECK(!input_mach_port_);
+  DCHECK(!input_run_loop_source_);
+  DCHECK(!polling_timer_.IsRunning());
+}
+
+CGEventRef UserInputMonitorMac::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<UserInputMonitorMac*>(context)->OnMouseEvent(mouse_pos);
+  }
+  return NULL;
+}
+
+void UserInputMonitorMac::StartMouseMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMac::StartMouseMonitoring,
+                   base::Unretained(this)));

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

This code will now crash if the calling thread e.g. calls
StartMouseMonitoring(), then deletes the UserInputMonitor, since tasks will be
executed against it on the UI thread after it has been deleted.  You need the
wrapper/core separation.

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

UserInputMonitor should always outlive the UI/IO threads due to their
declaration order in BrowserMainLoop. This is also documented in the comment in
user_input_monitor.h. So there is no crash.
The wrapper/core separation does not help actually because the core previously
called into the wrapper's callback with the wrapper "Unretained".

[Wez, 2013/08/21 23:43:54]

That's specific to the BrowserMainLoop caller - I thought we intended this to be
re-usable for Chromoting as well?
You'd use a WeakPtr back to the wrapper in that case.

+    return;
+  }
+  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 UserInputMonitorMac::StopMouseMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMac::StopMouseMonitoring,
+                   base::Unretained(this)));
+    return;
+  }
+  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 UserInputMonitorMac::StartKeyboardMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMac::StartKeyboardMonitoring,
+                   base::Unretained(this)));
+    return;
+  }
+  polling_timer_.Start(
+      FROM_HERE,
+      base::TimeDelta::FromMilliseconds(30),
+      base::Bind(&UserInputMonitorMac::PollKeyState, base::Unretained(this)));
+}
+
+void UserInputMonitorMac::StopKeyboardMonitoring() {
+  if (!ui_task_runner_->BelongsToCurrentThread()) {
+    ui_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&UserInputMonitorMac::StopKeyboardMonitoring,
+                   base::Unretained(this)));
+    return;
+  }
+  polling_timer_.Stop();
+}
+
+void UserInputMonitorMac::PollKeyState() {
+  DCHECK(ui_task_runner_->BelongsToCurrentThread());
+
+  bool key_pressed = false;
+  for (CGKeyCode key_index = 0; key_index < arraysize(prev_key_state_);
+       ++key_index) {
+    bool key_state =
+        CGEventSourceKeyState(kCGEventSourceStateHIDSystemState, key_index);
+    // 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)
+    OnKeyboardEvent(ui::ET_KEY_PRESSED, ui::VKEY_UNKNOWN);
+}
+
+}  // 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