Implement support for USB Xbox360 controllers without a driver on Mac.

content/browser/gamepad/xbox_data_fetcher_mac.h

+// 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.
+
+#ifndef CONTENT_BROWSER_GAMEPAD_XBOX_DATA_FETCHER_MAC_H_
+#define CONTENT_BROWSER_GAMEPAD_XBOX_DATA_FETCHER_MAC_H_
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <IOKit/IOKitLib.h>
+
+#include <set>
+
+#include "base/basictypes.h"
+#include "base/mac/scoped_ioobject.h"
+#include "base/mac/scoped_ioplugininterface.h"
+#include "base/memory/scoped_ptr.h"
+
+class XboxController {
+ public:
+  typedef enum {

[Mark Mentovai, 2013/04/24 16:57:20]

typedef enum is C. This is C++. Write enum StatusMessageType {. Same on line 32.

But you might not even need the type name: you never use StatusMessageType
anywhere, you only use its member constants. So you can just get away with enum
{ on this line, and the type can be anonymous.

[jeremya, 2013/04/26 03:47:40]

Done.

+    STATUS_MESSAGE_BUTTONS = 0,
+    STATUS_MESSAGE_LED = 1,
+    STATUS_MESSAGE_UNKNOWN = 2,

[Mark Mentovai, 2013/04/24 16:57:20]

Huh? If you don’t know what this message is and you don’t use it, why bother
defining it? Have you seen these status messages but just don’t know what to do
with them? If you want to keep this, a comment about what’s going on might clear
things up, like you did with the also-unused STATUS_MESSAGE_RUMBLE.

[jeremya, 2013/04/26 03:47:40]

I'll just remove it. (A lot of this code came from
https://github.com/josephg/Cocontroller)

+
+    // Apparently this message tells you if the rumble pack is disabled in the
+    // controller. If the rumble pack is disabled, vibration control messages
+    // have no effect.
+    STATUS_MESSAGE_RUMBLE = 3,
+  } StatusMessageType;

[Mark Mentovai, 2013/04/24 16:57:20]

This enum is not part of the public interface and is not used by any other
class. It can be private, or it can even be moved out of the header and into an
anonymous namespace in the .cc.

[jeremya, 2013/04/26 03:47:40]

Done.

+
+  // The LEDs are numbered top left, top right, bottom left, bottom right.

[Mark Mentovai, 2013/04/24 16:57:20]

Why is this information in a comment and not in the constant names, like
LED_FLASH_TOP_LEFT, etc.?

[jeremya, 2013/04/26 03:47:40]

Done.

+  typedef enum {
+    LED_OFF = 0,
+
+    // 2 quick flashes, then a series of slow flashes (about 1 per second).
+    LED_FLASH = 1,
+
+    // Flash three times then hold the LED on. This is the standard way to tell
+    // the player which player number they are.
+    LED_FLASH_1 = 2,
+    LED_FLASH_2 = 3,
+    LED_FLASH_3 = 4,
+    LED_FLASH_4 = 5,
+
+    // Simply turn on the numbered LED and turn all other LEDs off.
+    LED_HOLD_1 = 6,
+    LED_HOLD_2 = 7,
+    LED_HOLD_3 = 8,
+    LED_HOLD_4 = 9,
+
+    LED_ROTATE = 10,
+
+    LED_FLASH_FAST = 11,
+    LED_FLASH_SLOW = 12, // Flash about once per 3 seconds

[Mark Mentovai, 2013/04/24 16:57:20]

Style nit: two spaces between the last non-comment thing on a line and the //.

[jeremya, 2013/04/26 03:47:40]

Done.

+
+    // Flash alternating LEDs for a few seconds, then flash all LEDs about once
+    // per second
+    LED_ALTERNATE_PATTERN = 13,
+
+    // 14 is just another boring flashing speed.
+
+    // Flash all LEDs once then go black.
+    LED_FLASH_ONCE = 15,
+
+    LED_NUM_PATTERNS
+  } LEDPattern;
+
+  struct Data {
+    float buttons[17];
+    float axes[4];
+  };
+
+  class Delegate {
+   public:
+    virtual void XboxControllerGotData(XboxController* controller,
+                                       const Data& data) = 0;
+    virtual void XboxControllerError(XboxController* controller) = 0;
+  };

[Mark Mentovai, 2013/04/24 16:57:20]

The delegate shouldn’t be destroyed by “delete”ing a Delegate*, right? Declare
(but don’t define) a private destructor?

[jeremya, 2013/04/26 03:47:40]

Apparently that's an error:

../../content/browser/gamepad/gamepad_platform_data_fetcher_mac.h:31:39: error:
base class 'XboxDataFetcher::Delegate' has private destructor
                                      public XboxDataFetcher::Delegate {
                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../content/browser/gamepad/xbox_data_fetcher_mac.h:133:13: note: declared
private here
    virtual ~Delegate();
            ^

[Mark Mentovai, 2013/05/01 18:59:20]

jeremya wrote:
Oh duh, you’d need a protected destructor, not a private one. But that’d mean
you’d need an implementation. So maybe not worth doing just for a little
“delete” protection.

+
+  XboxController(Delegate* delegate_);

[Mark Mentovai, 2013/04/24 16:57:20]

explicit.

[jeremya, 2013/04/26 03:47:40]

Done.

+  virtual ~XboxController();
+
+  bool OpenDevice(io_service_t service);
+
+  void SetLEDPattern(LEDPattern pattern);
+
+  UInt32 location_id() { return location_id_; }
+  int GetVendorId() const;
+  int GetProductId() const;
+
+ private:
+  static void WriteComplete(void* context, IOReturn result, void* arg0);
+  static void GotData(void* context, IOReturn result, void* arg0);
+
+  void ProcessPacket(uint32 length);
+  void QueueRead();
+
+  void IOError();
+
+  // Handle for the USB device.
+  base::mac::ScopedIOPluginInterface<struct IOUSBDeviceStruct320> device_;
+
+  // Handle for the interface on the device which sends button and analog data.
+  // The other interfaces (for the ChatPad and headset) are ignored.
+  base::mac::ScopedIOPluginInterface<struct IOUSBInterfaceStruct300> interface_;
+
+  bool device_is_open_;
+  bool interface_is_open_;
+
+  CFRunLoopSourceRef source_;
+
+  // This will be set to the max packet size reported by the interface, which
+  // is 32 bytes. I would have expected USB to do message framing itself, but
+  // somehow we still sometimes (rarely!) get packets off the interface which
+  // aren't correctly framed. The 360 controller frames its packets with a 2
+  // byte header (type, total length) so we can reframe the packet data
+  // ourselves.
+  uint16 read_buffer_size_;
+  scoped_ptr<uint8[]> read_buffer_;
+
+  // The pattern that the LEDs on the device are currently displaying, or
+  // LED_NUM_PATTERNS if unknown.
+  LEDPattern led_pattern_;
+
+  UInt32 location_id_;
+
+  Delegate* delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(XboxController);
+};
+
+class XboxDataFetcher : public XboxController::Delegate {
+ public:
+  class Delegate {
+   public:
+    virtual void XboxDeviceAdd(XboxController* device) = 0;
+    virtual void XboxDeviceRemove(XboxController* device) = 0;
+    virtual void XboxValueChanged(XboxController* device,
+                                  const XboxController::Data& data) = 0;
+  };

[Mark Mentovai, 2013/04/24 16:57:20]

Private destructor declaration?

[jeremya, 2013/04/26 03:47:40]

Done.

[jeremya, 2013/04/26 03:47:40]

Done.

+
+  XboxDataFetcher(Delegate* delegate);

[Mark Mentovai, 2013/04/24 16:57:20]

explicit?

[jeremya, 2013/04/26 03:47:40]

Done.

+  virtual ~XboxDataFetcher();
+
+  void RegisterForNotifications();
+  void UnregisterFromNotifications();
+
+ private:
+  static void DeviceAdded(void* context, io_iterator_t iterator);
+  static void DeviceRemoved(void* context, io_iterator_t iterator);
+  void AddController(XboxController* controller);
+  void RemoveController(XboxController* controller);
+  void RemoveControllerByLocationID(uint32 id);
+  virtual void XboxControllerGotData(XboxController* controller,
+                                     const XboxController::Data& data) OVERRIDE;
+  virtual void XboxControllerError(XboxController* controller) OVERRIDE;
+
+  Delegate* delegate_;
+
+  std::set<XboxController*> controllers_;
+
+  bool listening_;
+
+  IONotificationPortRef port_;
+  CFRunLoopSourceRef source_;
+  base::mac::ScopedIOObject<io_iterator_t> device_added_iter_;
+  base::mac::ScopedIOObject<io_iterator_t> device_removed_iter_;
+
+  DISALLOW_COPY_AND_ASSIGN(XboxDataFetcher);
+};
+
+#endif  // CONTENT_BROWSER_GAMEPAD_XBOX_DATA_FETCHER_MAC_H_