Introducing chrome.usb.getDevices/openDevice API

chrome/browser/usb/usb_service.h

 // 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.
 
 #ifndef CHROME_BROWSER_USB_USB_SERVICE_H_
 #define CHROME_BROWSER_USB_USB_SERVICE_H_
 
 #include <map>
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/singleton.h"
-#include "chrome/browser/usb/usb_device.h"
 
 namespace base {
 
 template <class T> class DeleteHelper;
 
 }  // namespace base
 
 template <typename T> struct DefaultSingletonTraits;
+
+typedef struct libusb_device* PlatformUsbDevice;
+
 class UsbContext;
+class UsbDevice;
 
 // The USB service handles creating and managing an event handler thread that is
-// used to manage and dispatch USB events. It is also responsbile for device
+// used to manage and dispatch USB events. It is also responsible for device
 // discovery on the system, which allows it to re-use device handles to prevent
 // competition for the same USB device.
 class UsbService {
  public:
   typedef scoped_ptr<std::vector<scoped_refptr<UsbDevice> > >
       ScopedDeviceVector;
 
   // Must be called on FILE thread.
   static UsbService* GetInstance();
 
-  // Find all of the devices attached to the system that are identified by
-  // |vendor_id| and |product_id|, inserting them into |devices|. Clears
-  // |devices| before use. Calls |callback| once |devices| is populated.
-  // The result will be sorted by id in increasing order. Must be called on
-  // FILE thread.
-  void FindDevices(
-      const uint16 vendor_id,
-      const uint16 product_id,
-      int interface_id,
-      const base::Callback<void(ScopedDeviceVector vector)>& callback);
+  scoped_refptr<UsbDevice> GetDeviceById(uint32 unique_id);

[pfeldman, 2013/09/04 07:16:55]

What is this id? How does user obtain one? Ref-counted objects are typically
using instances for identity. It sounds like the only way to obtain this id is
to ask for it from the device. I.e. the caller has had the device reference. If
that is for client-side binding, then this mapping belongs to the client.

 
   // Get all of the devices attached to the system, inserting them into
   // |devices|. Clears |devices| before use. The result will be sorted by id
   // in increasing order. Must be called on FILE thread.
   void GetDevices(std::vector<scoped_refptr<UsbDevice> >* devices);
 
  private:
   friend struct DefaultSingletonTraits<UsbService>;
   friend class base::DeleteHelper<UsbService>;
 
   UsbService();
   virtual ~UsbService();
 
   // Return true if |device|'s vendor and product identifiers match |vendor_id|
   // and |product_id|.
   static bool DeviceMatches(scoped_refptr<UsbDevice> device,
                             const uint16 vendor_id,
                             const uint16 product_id);
 
-  // This method is called when permission broker replied our request.
-  // We will simply relay it to FILE thread.
-  void OnRequestUsbAccessReplied(
-      const uint16 vendor_id,
-      const uint16 product_id,
-      const base::Callback<void(ScopedDeviceVector vector)>& callback,
-      bool success);
-
-  // FindDevicesImpl is called by FindDevices on ChromeOS after the permission
-  // broker has signaled that permission has been granted to access the
-  // underlying device nodes. On other platforms, it is called directly by
-  // FindDevices.
-  void FindDevicesImpl(
-      const uint16 vendor_id,
-      const uint16 product_id,
-      const base::Callback<void(ScopedDeviceVector vector)>& callback,
-      bool success);
-
   // Enumerate USB devices from OS and Update devices_ map.
   void RefreshDevices();
 
   scoped_refptr<UsbContext> context_;
 
+  uint32 next_unique_id_;
+
   // The map from PlatformUsbDevices to UsbDevices.
   typedef std::map<PlatformUsbDevice, scoped_refptr<UsbDevice> > DeviceMap;
   DeviceMap devices_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbService);
 };
 
 #endif  // CHROME_BROWSER_USB_USB_SERVICE_H_