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// 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_service.h"
#include <set>
#include <vector>
#include "base/basictypes.h"
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/logging.h"
#include "base/memory/ref_counted.h"
#include "base/stl_util.h"
#include "chrome/browser/chrome_notification_types.h"
#include "chrome/browser/usb/usb_context.h"
#include "chrome/browser/usb/usb_device.h"
#include "chrome/browser/usb/usb_device_handle.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
#include "content/public/browser/notification_service.h"
#include "third_party/libusb/src/libusb/libusb.h"
namespace content {
class NotificationDetails;
class NotificationSource;
} // namespace content
using content::BrowserThread;
using std::vector;
namespace {
// This is the one and only instance of UsbService. The reason not to use
// Singleton is: 1. Singleton focuses on solving race conditions and at-exit
// deletion, none of them are needed here, and 2. Singleton does not provide
// a way to clear the pointer after the instance being destroyed.
UsbService* g_usb_service_instance = NULL;
bool g_usb_service_instance_destroyed = false;
class ExitObserver : public content::NotificationObserver {
public:
ExitObserver() {
BrowserThread::PostTask(
BrowserThread::UI, FROM_HERE,
base::Bind(&content::NotificationRegistrar::Add,
base::Unretained(®istrar_), this,
chrome::NOTIFICATION_APP_TERMINATING,
content::NotificationService::AllSources()));
}
private:
// content::NotificationObserver
virtual void Observe(int type,
const content::NotificationSource& source,
const content::NotificationDetails& details) OVERRIDE {
if (type == chrome::NOTIFICATION_APP_TERMINATING) {
BrowserThread::DeleteSoon(BrowserThread::FILE,
FROM_HERE,
g_usb_service_instance);
delete this;
}
}
content::NotificationRegistrar registrar_;
};
} // namespace
UsbService::UsbService(PlatformUsbContext context)
: context_(new UsbContext(context)),
next_unique_id_(0) {
DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
}
UsbService::~UsbService() {
DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
// Prevents creating a new UsbService.
g_usb_service_instance_destroyed = true;
g_usb_service_instance = NULL;
for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
it->second->OnDisconnect();
}
}
UsbService* UsbService::GetInstance() {
DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
if (g_usb_service_instance_destroyed)
return NULL;
if (!g_usb_service_instance) {
PlatformUsbContext context = NULL;
if (libusb_init(&context) != LIBUSB_SUCCESS)
return NULL;
if (!context)
return NULL;
g_usb_service_instance = new UsbService(context);
// Will be deleted upon NOTIFICATION_APP_TERMINATING.
new ExitObserver();
}
return g_usb_service_instance;
}
void UsbService::GetDevices(std::vector<scoped_refptr<UsbDevice> >* devices) {
DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
STLClearObject(devices);
RefreshDevices();
for (DeviceMap::iterator it = devices_.begin(); it != devices_.end(); ++it) {
devices->push_back(it->second);
}
}
scoped_refptr<UsbDevice> UsbService::GetDeviceById(uint32 unique_id) {
DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
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::RefreshDevices() {
DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
libusb_device** platform_devices = NULL;
const ssize_t device_count =
libusb_get_device_list(context_->context(), &platform_devices);
std::set<UsbDevice*> connected_devices;
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);
}
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