Fail gracefully when libusb_init fails

BUG=280668

Review URL: https://chromiumcodereview.appspot.com/23571007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221508 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/api/usb/usb_api.cc

@@ -59,6 +59,8 @@ namespace {
 const char kDataKey[] = "data";
 const char kResultCodeKey[] = "resultCode";
 
+const char kErrorInitService[] = "Failed to initialize USB service.";
+
 const char kErrorOpen[] = "Failed to open device.";
 const char kErrorCancelled[] = "Transfer was cancelled.";
 const char kErrorDisconnect[] = "Device disconnected.";
@@ -412,6 +414,10 @@ UsbAsyncApiFunction::GetDeviceOrOrCompleteWithError(
   }
 
   UsbService* service = UsbService::GetInstance();
+  if (!service) {
+    CompleteWithError(kErrorInitService);
+    return NULL;
+  }
   scoped_refptr<UsbDevice> device;
 
   device = service->GetDeviceById(input_device.device);
@@ -537,6 +543,11 @@ void UsbFindDevicesFunction::AsyncWorkStart() {
   }
 
   UsbService *service = UsbService::GetInstance();
+  if (!service) {
+    CompleteWithError(kErrorInitService);
+    return;
+  }
+
   ScopedDeviceVector devices(new DeviceVector());
   service->GetDevices(devices.get());
 
@@ -624,6 +635,11 @@ void UsbGetDevicesFunction::AsyncWorkStart() {
   }
 
   UsbService* service = UsbService::GetInstance();
+  if (!service) {
+    CompleteWithError(kErrorInitService);
+    return;
+  }
+
   DeviceVector devices;
   service->GetDevices(&devices);
 

chrome/browser/usb/usb_context.cc

@@ -60,9 +60,8 @@ void UsbContext::UsbEventHandler::ThreadMain() {
   VLOG(1) << "UsbEventHandler shutting down.";
 }
 
-UsbContext::UsbContext() : context_(NULL) {
+UsbContext::UsbContext(PlatformUsbContext context) : context_(context) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  CHECK_EQ(0, libusb_init(&context_)) << "Cannot initialize libusb";
   event_handler_ = new UsbEventHandler(context_);
 }
 

chrome/browser/usb/usb_context.h

@@ -27,7 +27,7 @@ class UsbContext : public base::RefCountedThreadSafe<UsbContext> {
   friend class UsbService;
   friend class base::RefCountedThreadSafe<UsbContext>;
 
-  UsbContext();
+  explicit UsbContext(PlatformUsbContext context);
   virtual ~UsbContext();
 
  private:

chrome/browser/usb/usb_context_unittest.cc

@@ -7,6 +7,7 @@
 #include "base/threading/platform_thread.h"
 #include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/libusb/src/libusb/libusb.h"
 
 namespace {
 
@@ -14,7 +15,8 @@ class UsbContextTest : public testing::Test {
  protected:
   class UsbContextForTest : public UsbContext {
    public:
-    UsbContextForTest() : UsbContext() {}
+    explicit UsbContextForTest(PlatformUsbContext context)
+        : UsbContext(context) {}
    private:
     virtual ~UsbContextForTest() {}
     DISALLOW_COPY_AND_ASSIGN(UsbContextForTest);
@@ -36,7 +38,10 @@ class UsbContextTest : public testing::Test {
 TEST_F(UsbContextTest, MAYBE_GracefulShutdown) {
   base::TimeTicks start = base::TimeTicks::Now();
   {
-    scoped_refptr<UsbContextForTest> context(new UsbContextForTest());
+    PlatformUsbContext platform_context;
+    ASSERT_EQ(LIBUSB_SUCCESS, libusb_init(&platform_context));
+    scoped_refptr<UsbContextForTest> context(
+        new UsbContextForTest(platform_context));
   }
   base::TimeDelta elapse = base::TimeTicks::Now() - start;
   if (elapse > base::TimeDelta::FromSeconds(2)) {

chrome/browser/usb/usb_service.cc

@@ -64,8 +64,8 @@ class ExitObserver : public content::NotificationObserver {
 
 using content::BrowserThread;
 
-UsbService::UsbService()
-    : context_(new UsbContext()),
+UsbService::UsbService(PlatformUsbContext context)
+    : context_(new UsbContext(context)),
       next_unique_id_(0) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   // Will be deleted upon NOTIFICATION_APP_TERMINATING.
@@ -79,10 +79,22 @@ UsbService::~UsbService() {
   }
 }
 
+struct InitUsbContextTraits : public LeakySingletonTraits<UsbService> {
+  // LeakySingletonTraits<UsbService>
+  static UsbService* New() {
+    PlatformUsbContext context = NULL;
+    if (libusb_init(&context) != LIBUSB_SUCCESS)
+      return NULL;
+    if (!context)
+      return NULL;
+    return new UsbService(context);
+  }
+};
+
 UsbService* UsbService::GetInstance() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   // UsbService deletes itself upon APP_TERMINATING.
-  return Singleton<UsbService, LeakySingletonTraits<UsbService> >::get();
+  return Singleton<UsbService, InitUsbContextTraits>::get();
 }
 
 void UsbService::GetDevices(std::vector<scoped_refptr<UsbDevice> >* devices) {

chrome/browser/usb/usb_service.h

@@ -20,9 +20,11 @@ template <class T> class DeleteHelper;
 
 }  // namespace base
 
+struct InitUsbContextTraits;
 template <typename T> struct DefaultSingletonTraits;
 
 typedef struct libusb_device* PlatformUsbDevice;
+typedef struct libusb_context* PlatformUsbContext;
 
 class UsbContext;
 class UsbDevice;
@@ -37,6 +39,7 @@ class UsbService {
       ScopedDeviceVector;
 
   // Must be called on FILE thread.
+  // Returns NULL when failed to initialized.
   static UsbService* GetInstance();
 
   scoped_refptr<UsbDevice> GetDeviceById(uint32 unique_id);
@@ -47,10 +50,11 @@ class UsbService {
   void GetDevices(std::vector<scoped_refptr<UsbDevice> >* devices);
 
  private:
+  friend struct InitUsbContextTraits;
   friend struct DefaultSingletonTraits<UsbService>;
   friend class base::DeleteHelper<UsbService>;
 
-  UsbService();
+  explicit UsbService(PlatformUsbContext context);
   virtual ~UsbService();
 
   // Return true if |device|'s vendor and product identifiers match |vendor_id|