Resize control transfer buffers so users don't have to.

chrome/browser/usb/usb_device.cc

 // 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 "chrome/browser/usb/usb_device.h"
 
 #include "base/stl_util.h"
 #include "base/synchronization/lock.h"
 #include "chrome/browser/usb/usb_service.h"
 #include "third_party/libusb/libusb.h"
@@ skipping 110 matching lines @@
   libusb_free_transfer(handle);
 }
 
 void UsbDevice::ControlTransfer(const TransferDirection direction,
     const TransferRequestType request_type, const TransferRecipient recipient,
     const uint8 request, const uint16 value, const uint16 index,
     net::IOBuffer* buffer, const size_t length, const unsigned int timeout,
     const UsbTransferCallback& callback) {
   CheckDevice();
 
+  scoped_refptr<net::IOBuffer> resized_buffer(new net::IOBufferWithSize(
+      LIBUSB_CONTROL_SETUP_SIZE + length));
+  memcpy(resized_buffer->data() + LIBUSB_CONTROL_SETUP_SIZE, buffer->data(),
+         length);
+
   struct libusb_transfer* const transfer = libusb_alloc_transfer(0);
   const uint8 converted_type = CreateRequestType(direction, request_type,
                                                  recipient);
-  libusb_fill_control_setup(reinterpret_cast<uint8*>(buffer->data()),
+  libusb_fill_control_setup(reinterpret_cast<uint8*>(resized_buffer->data()),
                             converted_type, request, value, index, length);
   libusb_fill_control_transfer(transfer, handle_, reinterpret_cast<uint8*>(
-      buffer->data()), reinterpret_cast<libusb_transfer_cb_fn>(
+      resized_buffer->data()), reinterpret_cast<libusb_transfer_cb_fn>(
           &HandleTransferCompletion), this, timeout);
-  SubmitTransfer(transfer, buffer, callback);
+  SubmitTransfer(transfer, resized_buffer, callback);
 }
 
 void UsbDevice::BulkTransfer(const TransferDirection direction,
     const uint8 endpoint, net::IOBuffer* buffer, const size_t length,
     const unsigned int timeout, const UsbTransferCallback& callback) {
   CheckDevice();
 
   struct libusb_transfer* const transfer = libusb_alloc_transfer(0);
   const uint8 new_endpoint = ConvertTransferDirection(direction) | endpoint;
   libusb_fill_bulk_transfer(transfer, handle_, new_endpoint,
@@ skipping 45 matching lines @@
 
   Transfer transfer;
   transfer.buffer = buffer;
   transfer.callback = callback;
 
   {
     base::AutoLock lock(lock_);
     transfers_[handle] = transfer;
   }
 }