device/usb/usb_service_impl.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "device/usb/usb_service.h"
   6
   7 #include <map>
   8 #include <set>
   9
  10 #include "base/lazy_instance.h"
  11 #include "base/message_loop/message_loop.h"
  12 #include "base/single_thread_task_runner.h"
  13 #include "base/stl_util.h"
  14 #include "device/usb/usb_context.h"
  15 #include "device/usb/usb_device_impl.h"
  16 #include "device/usb/usb_error.h"
  17 #include "third_party/libusb/src/libusb/libusb.h"
  18
  19 namespace device {
  20
  21 namespace {
  22
  23 base::LazyInstance<scoped_ptr<UsbService> >::Leaky g_usb_service_instance =
  24     LAZY_INSTANCE_INITIALIZER;
  25
  26 }  // namespace
  27
  28 typedef struct libusb_device* PlatformUsbDevice;
  29 typedef struct libusb_context* PlatformUsbContext;
  30
  31 class UsbServiceImpl : public UsbService,
  32                        private base::MessageLoop::DestructionObserver {
  33  public:
  34   explicit UsbServiceImpl(
  35       PlatformUsbContext context,
  36       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner);
  37   ~UsbServiceImpl() override;
  38
  39  private:
  40   // device::UsbService implementation
  41   scoped_refptr<UsbDevice> GetDeviceById(uint32 unique_id) override;
  42   void GetDevices(std::vector<scoped_refptr<UsbDevice>>* devices) override;
  43
  44   // base::MessageLoop::DestructionObserver implementation.
  45   void WillDestroyCurrentMessageLoop() override;
  46
  47   // Enumerate USB devices from OS and update devices_ map.
  48   void RefreshDevices();
  49
  50   scoped_refptr<UsbContext> context_;
  51   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  52   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
  53
  54   // TODO(reillyg): Figure out a better solution.
  55   uint32 next_unique_id_;
  56
  57   // The map from unique IDs to UsbDevices.
  58   typedef std::map<uint32, scoped_refptr<UsbDeviceImpl> > DeviceMap;
  59   DeviceMap devices_;
  60
  61   // The map from PlatformUsbDevices to UsbDevices.
  62   typedef std::map<PlatformUsbDevice, scoped_refptr<UsbDeviceImpl> >
  63       PlatformDeviceMap;
  64   PlatformDeviceMap platform_devices_;
  65
  66   DISALLOW_COPY_AND_ASSIGN(UsbServiceImpl);
  67 };
  68
  69 scoped_refptr<UsbDevice> UsbServiceImpl::GetDeviceById(uint32 unique_id) {
  70   DCHECK(CalledOnValidThread());
  71   RefreshDevices();
  72   DeviceMap::iterator it = devices_.find(unique_id);
  73   if (it != devices_.end()) {
  74     return it->second;
  75   }
  76   return NULL;
  77 }
  78
  79 void UsbServiceImpl::GetDevices(
  80     std::vector<scoped_refptr<UsbDevice> >* devices) {
  81   DCHECK(CalledOnValidThread());
  82   STLClearObject(devices);
  83   RefreshDevices();
  84
  85   for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
  86     devices->push_back(it->second);
  87   }
  88 }
  89
  90 void UsbServiceImpl::WillDestroyCurrentMessageLoop() {
  91   DCHECK(CalledOnValidThread());
  92   g_usb_service_instance.Get().reset(NULL);
  93 }
  94
  95 UsbServiceImpl::UsbServiceImpl(
  96     PlatformUsbContext context,
  97     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner)
  98     : context_(new UsbContext(context)),
  99       ui_task_runner_(ui_task_runner),
 100       next_unique_id_(0) {
 101   base::MessageLoop::current()->AddDestructionObserver(this);
 102 }
 103
 104 UsbServiceImpl::~UsbServiceImpl() {
 105   base::MessageLoop::current()->RemoveDestructionObserver(this);
 106   for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
 107     it->second->OnDisconnect();
 108   }
 109 }
 110
 111 void UsbServiceImpl::RefreshDevices() {
 112   DCHECK(CalledOnValidThread());
 113
 114   libusb_device** platform_devices = NULL;
 115   const ssize_t device_count =
 116       libusb_get_device_list(context_->context(), &platform_devices);
 117   if (device_count < 0) {
 118     VLOG(1) << "Failed to get device list: "
 119             << ConvertPlatformUsbErrorToString(device_count);
 120   }
 121
 122   std::set<UsbDevice*> connected_devices;
 123   std::vector<PlatformUsbDevice> disconnected_devices;
 124
 125   // Populates new devices.
 126   for (ssize_t i = 0; i < device_count; ++i) {
 127     if (!ContainsKey(platform_devices_, platform_devices[i])) {
 128       libusb_device_descriptor descriptor;
 129       const int rv =
 130           libusb_get_device_descriptor(platform_devices[i], &descriptor);
 131       // This test is needed. A valid vendor/produce pair is required.
 132       if (rv != LIBUSB_SUCCESS) {
 133         VLOG(1) << "Failed to get device descriptor: "
 134                 << ConvertPlatformUsbErrorToString(rv);
 135         continue;
 136       }
 137
 138       uint32 unique_id;
 139       do {
 140         unique_id = ++next_unique_id_;
 141       } while (devices_.find(unique_id) != devices_.end());
 142
 143       scoped_refptr<UsbDeviceImpl> new_device(
 144           new UsbDeviceImpl(context_,
 145                             ui_task_runner_,
 146                             platform_devices[i],
 147                             descriptor.idVendor,
 148                             descriptor.idProduct,
 149                             unique_id));
 150       platform_devices_[platform_devices[i]] = new_device;
 151       devices_[unique_id] = new_device;
 152       connected_devices.insert(new_device.get());
 153     } else {
 154       connected_devices.insert(platform_devices_[platform_devices[i]].get());
 155     }
 156   }
 157
 158   // Find disconnected devices.
 159   for (PlatformDeviceMap::iterator it = platform_devices_.begin();
 160        it != platform_devices_.end();
 161        ++it) {
 162     if (!ContainsKey(connected_devices, it->second.get())) {
 163       disconnected_devices.push_back(it->first);
 164       devices_.erase(it->second->unique_id());
 165       it->second->OnDisconnect();
 166     }
 167   }
 168
 169   // Remove disconnected devices from platform_devices_.
 170   for (size_t i = 0; i < disconnected_devices.size(); ++i) {
 171     // UsbDevice will be destroyed after this. The corresponding
 172     // PlatformUsbDevice will be unref'ed during this process.
 173     platform_devices_.erase(disconnected_devices[i]);
 174   }
 175
 176   libusb_free_device_list(platform_devices, true);
 177 }
 178
 179 // static
 180 UsbService* UsbService::GetInstance(
 181     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
 182   UsbService* instance = g_usb_service_instance.Get().get();
 183   if (!instance) {
 184     PlatformUsbContext context = NULL;
 185
 186     const int rv = libusb_init(&context);
 187     if (rv != LIBUSB_SUCCESS) {
 188       VLOG(1) << "Failed to initialize libusb: "
 189               << ConvertPlatformUsbErrorToString(rv);
 190       return NULL;
 191     }
 192     if (!context)
 193       return NULL;
 194
 195     instance = new UsbServiceImpl(context, ui_task_runner);
 196     g_usb_service_instance.Get().reset(instance);
 197   }
 198   return instance;
 199 }
 200
 201 // static
 202 void UsbService::SetInstanceForTest(UsbService* instance) {
 203   g_usb_service_instance.Get().reset(instance);
 204 }
 205
 206 }  // namespace device