Fail gracefully when libusb_init fails

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

 // 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/extensions/api/usb/usb_api.h"
 
 #include <string>
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 41 matching lines @@
 using usb::UsageType;
 
 typedef std::vector<scoped_refptr<UsbDevice> > DeviceVector;
 typedef scoped_ptr<DeviceVector> ScopedDeviceVector;
 
 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.";
 const char kErrorGeneric[] = "Transfer failed.";
 const char kErrorNotSupported[] = "Not supported on this platform.";
 const char kErrorOverflow[] = "Inbound transfer overflow.";
 const char kErrorStalled[] = "Transfer stalled.";
 const char kErrorTimeout[] = "Transfer timed out.";
 const char kErrorTransferLength[] = "Transfer length is insufficient.";
 
@@ skipping 333 matching lines @@
   UsbDevicePermission::CheckParam param(
       vendor_id, product_id, UsbDevicePermissionData::UNSPECIFIED_INTERFACE);
   if (!PermissionsData::CheckAPIPermissionWithParam(
           GetExtension(), APIPermission::kUsbDevice, &param)) {
     LOG(WARNING) << "Insufficient permissions to access device.";
     CompleteWithError(kErrorPermissionDenied);
     return NULL;
   }
 
   UsbService* service = UsbService::GetInstance();
+  if (!service) {
+    CompleteWithError(kErrorInitService);
+    return NULL;
+  }
   scoped_refptr<UsbDevice> device;
 
   device = service->GetDeviceById(input_device.device);
 
   if (!device) {
     CompleteWithError(kErrorNoDevice);
     return NULL;
   }
 
   if (device->vendor_id() != input_device.vendor_id ||
@@ skipping 105 matching lines @@
       UsbDevicePermissionData::ANY_INTERFACE;
   UsbDevicePermission::CheckParam param(vendor_id, product_id, interface_id);
   if (!PermissionsData::CheckAPIPermissionWithParam(
           GetExtension(), APIPermission::kUsbDevice, &param)) {
     LOG(WARNING) << "Insufficient permissions to access device.";
     CompleteWithError(kErrorPermissionDenied);
     return;
   }
 
   UsbService *service = UsbService::GetInstance();
+  if (!service) {
+    CompleteWithError(kErrorInitService);
+    return;
+  }
+
   ScopedDeviceVector devices(new DeviceVector());
   service->GetDevices(devices.get());
 
   for (DeviceVector::iterator it = devices->begin();
       it != devices->end();) {
     if ((*it)->vendor_id() != vendor_id || (*it)->product_id() != product_id) {
       it = devices->erase(it);
     } else {
       ++it;
     }
@@ skipping 67 matching lines @@
   UsbDevicePermission::CheckParam param(
       vendor_id, product_id, UsbDevicePermissionData::UNSPECIFIED_INTERFACE);
   if (!PermissionsData::CheckAPIPermissionWithParam(
           GetExtension(), APIPermission::kUsbDevice, &param)) {
     LOG(WARNING) << "Insufficient permissions to access device.";
     CompleteWithError(kErrorPermissionDenied);
     return;
   }
 
   UsbService* service = UsbService::GetInstance();
+  if (!service) {
+    CompleteWithError(kErrorInitService);
+    return;
+  }
+
   DeviceVector devices;
   service->GetDevices(&devices);
 
   for (DeviceVector::iterator it = devices.begin(); it != devices.end();) {
     if ((*it)->vendor_id() != vendor_id || (*it)->product_id() != product_id) {
       it = devices.erase(it);
     } else {
       ++it;
     }
   }
@@ skipping 506 matching lines @@
     SetResult(new base::FundamentalValue(false));
     CompleteWithError(kErrorResetDevice);
     return;
   }
 
   SetResult(new base::FundamentalValue(true));
   AsyncWorkCompleted();
 }
 
 }  // namespace extensions