Extracted UsbService as interface.

components/usb_service/usb_service.cc

-// 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 "components/usb_service/usb_service.h"
-
-#include <set>
-#include <vector>
-
-#include "base/lazy_instance.h"
-#include "base/stl_util.h"
-#include "components/usb_service/usb_context.h"
-#include "components/usb_service/usb_device.h"
-#include "content/public/browser/browser_thread.h"
-#include "third_party/libusb/src/libusb/libusb.h"
-
-namespace usb_service {
-
-namespace {
-
-base::LazyInstance<scoped_ptr<UsbService> >::Leaky g_usb_service_instance =
-    LAZY_INSTANCE_INITIALIZER;
-
-}  // namespace
-
-// static
-UsbService* UsbService::GetInstance() {
-  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
-  UsbService* instance = g_usb_service_instance.Get().get();
-  if (!instance) {
-    PlatformUsbContext context = NULL;
-    if (libusb_init(&context) != LIBUSB_SUCCESS)
-      return NULL;
-    if (!context)
-      return NULL;
-
-    instance = new UsbService(context);
-    g_usb_service_instance.Get().reset(instance);
-  }
-  return instance;
-}
-
-scoped_refptr<UsbDevice> UsbService::GetDeviceById(uint32 unique_id) {
-  DCHECK(CalledOnValidThread());
-  RefreshDevices();
-  for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
-    if (it->second->unique_id() == unique_id)
-      return it->second;
-  }
-  return NULL;
-}
-
-void UsbService::GetDevices(std::vector<scoped_refptr<UsbDevice> >* devices) {
-  DCHECK(CalledOnValidThread());
-  STLClearObject(devices);
-  RefreshDevices();
-
-  for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
-    devices->push_back(it->second);
-  }
-}
-
-void UsbService::WillDestroyCurrentMessageLoop() {
-  DCHECK(CalledOnValidThread());
-  g_usb_service_instance.Get().reset(NULL);
-}
-
-UsbService::UsbService(PlatformUsbContext context)
-    : context_(new UsbContext(context)), next_unique_id_(0) {
-  base::MessageLoop::current()->AddDestructionObserver(this);
-}
-
-UsbService::~UsbService() {
-  base::MessageLoop::current()->RemoveDestructionObserver(this);
-  for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
-    it->second->OnDisconnect();
-  }
-}
-
-void UsbService::RefreshDevices() {
-  DCHECK(CalledOnValidThread());
-
-  libusb_device** platform_devices = NULL;
-  const ssize_t device_count =
-      libusb_get_device_list(context_->context(), &platform_devices);
-
-  std::set<UsbDevice*> connected_devices;
-  std::vector<PlatformUsbDevice> disconnected_devices;
-
-  // Populates new devices.
-  for (ssize_t i = 0; i < device_count; ++i) {
-    if (!ContainsKey(devices_, platform_devices[i])) {
-      libusb_device_descriptor descriptor;
-      // This test is needed. A valid vendor/produce pair is required.
-      if (0 != libusb_get_device_descriptor(platform_devices[i], &descriptor))
-        continue;
-      UsbDevice* new_device = new UsbDevice(context_,
-                                            platform_devices[i],
-                                            descriptor.idVendor,
-                                            descriptor.idProduct,
-                                            ++next_unique_id_);
-      devices_[platform_devices[i]] = new_device;
-      connected_devices.insert(new_device);
-    } else {
-      connected_devices.insert(devices_[platform_devices[i]].get());
-    }
-  }
-
-  // Find disconnected devices.
-  for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
-    if (!ContainsKey(connected_devices, it->second)) {
-      disconnected_devices.push_back(it->first);
-    }
-  }
-
-  // Remove disconnected devices from devices_.
-  for (size_t i = 0; i < disconnected_devices.size(); ++i) {
-    // UsbDevice will be destroyed after this. The corresponding
-    // PlatformUsbDevice will be unref'ed during this process.
-    devices_.erase(disconnected_devices[i]);
-  }
-
-  libusb_free_device_list(platform_devices, true);
-}
-
-}  // namespace usb_service