HID backend

device/hid/hid_connection_win.h

+// Copyright (c) 2014 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 DEVICE_HID_HID_CONNECTION_WIN_H_
+#define DEVICE_HID_HID_CONNECTION_WIN_H_
+
+#include <windows.h>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/win/object_watcher.h"
+#include "device/hid/hid_connection.h"
+#include "device/hid/hid_device_info.h"
+
+namespace device {
+
+class AsyncTransfer : public base::RefCountedThreadSafe<AsyncTransfer>,
+                      public base::win::ObjectWatcher::Delegate {
+ public:

[Ken Rockot(use gerrit already), 2014/01/21 23:03:39]

base::MessageLoopForIO::IOHandler essentially provides the same abstraction as
your AsyncTransfer.

See c/b/e/api/serial_io_handler_win.{h,cc} for an example usage

[Bei Zhang, 2014/01/24 12:48:47]

As I tested, it only works on IO thread, were IO is not allowed...
The current approach works on any thread. I moved it into the HidServiceWin
class.

+  AsyncTransfer(HANDLE file,
+                scoped_refptr<net::IOBuffer> buffer,
+                const HidIOCallback& callback,
+                bool is_read);
+
+  OVERLAPPED* GetOverlappedPtr();
+  DWORD* GetActualSizePtr();
+
+  void StartWatching(BOOL result_from_winapi);
+
+ private:
+  friend class base::RefCountedThreadSafe<AsyncTransfer>;
+
+  virtual ~AsyncTransfer();
+
+  // base::win::ObjectWatcher::Delegate:
+  virtual void OnObjectSignaled(HANDLE object) OVERRIDE;
+
+  HANDLE file_;
+  OVERLAPPED overlapped_;
+  scoped_refptr<net::IOBuffer> buffer_;
+  base::win::ScopedHandle event_;
+  HidIOCallback callback_;
+  base::win::ObjectWatcher watcher_;
+  DWORD actual_size_;
+
+  // For input transfer, if the first byte is zero, we need to remove it.
+  bool is_read_;
+
+  DISALLOW_COPY_AND_ASSIGN(AsyncTransfer);
+};
+
+class HidConnectionWin : public HidConnection {
+ public:
+  HidConnectionWin(HidDeviceInfo device_info);
+
+  virtual void Read(const HidIOCallback& callback) OVERRIDE;
+  virtual void Write(scoped_refptr<net::IOBuffer> buffer,
+                     size_t size,
+                     const HidIOCallback& callback) OVERRIDE;
+  virtual void GetFeatureReport(const HidIOCallback& callback) OVERRIDE;
+  virtual void SendFeatureReport(scoped_refptr<net::IOBuffer> buffer,
+                                 size_t size,
+                                 const HidIOCallback& callback) OVERRIDE;
+
+  bool available() const { return available_; }
+
+ private:
+  ~HidConnectionWin();
+
+  base::win::ScopedHandle file_;
+
+  DISALLOW_COPY_AND_ASSIGN(HidConnectionWin);
+
+  bool available_;
+};
+
+}  // namespace device
+
+#endif  // DEVICE_HID_HID_CONNECTION_WIN_H_