| // Copyright 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. |
| |
| #include "device/usb/usb_context.h" |
| |
| #include "base/atomicops.h" |
| #include "base/logging.h" |
| #include "base/macros.h" |
| #include "base/threading/simple_thread.h" |
| #include "device/usb/usb_error.h" |
| #include "third_party/libusb/src/libusb/interrupt.h" |
| #include "third_party/libusb/src/libusb/libusb.h" |
| |
| namespace device { |
| |
| // The UsbEventHandler works around a design flaw in the libusb interface. There |
| // is currently no way to signal to libusb that any caller into one of the event |
| // handler calls should return without handling any events. |
| class UsbContext::UsbEventHandler : public base::SimpleThread { |
| public: |
| explicit UsbEventHandler(libusb_context* context); |
| ~UsbEventHandler() override; |
| |
| // base::SimpleThread |
| void Run() override; |
| |
| void Stop(); |
| |
| private: |
| base::subtle::Atomic32 running_; |
| libusb_context* context_; |
| DISALLOW_COPY_AND_ASSIGN(UsbEventHandler); |
| }; |
| |
| UsbContext::UsbEventHandler::UsbEventHandler(libusb_context* context) |
| : base::SimpleThread("UsbEventHandler"), context_(context) { |
| base::subtle::Release_Store(&running_, 1); |
| } |
| |
| UsbContext::UsbEventHandler::~UsbEventHandler() { |
| libusb_exit(context_); |
| } |
| |
| void UsbContext::UsbEventHandler::Run() { |
| VLOG(1) << "UsbEventHandler started."; |
| |
| while (base::subtle::Acquire_Load(&running_)) { |
| const int rv = libusb_handle_events(context_); |
| if (rv != LIBUSB_SUCCESS) { |
| VLOG(1) << "Failed to handle events: " |
| << ConvertPlatformUsbErrorToString(rv); |
| } |
| } |
| |
| VLOG(1) << "UsbEventHandler shutting down."; |
| } |
| |
| void UsbContext::UsbEventHandler::Stop() { |
| base::subtle::Release_Store(&running_, 0); |
| libusb_interrupt_handle_event(context_); |
| } |
| |
| UsbContext::UsbContext(PlatformUsbContext context) : context_(context) { |
| // Ownership of the PlatformUsbContext is passed to the event handler thread. |
| event_handler_.reset(new UsbEventHandler(context_)); |
| event_handler_->Start(); |
| } |
| |
| UsbContext::~UsbContext() { |
| event_handler_->Stop(); |
| event_handler_->Join(); |
| } |
| |
| } // namespace device |