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1 /*
2  * Copyright (C) 2017 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 #pragma once
17 
18 #include <functional>
19 #include <memory>
20 
21 #include <stdint.h>
22 #include <libusb/libusb.h>
23 #include "common/libs/usbforward/protocol.h"
24 
25 namespace usb_forward {
26 
27 // TransportRequest represents a libusb asynchronous transport request.
28 // This class encapsulates everything that is necessary to complete
29 // transfer.
30 class TransportRequest final {
31  public:
32   // CallbackType describes what kind of function can receive call when this
33   // asynchronous call is complete.
34   // Parameters passed to callback, in order:
35   // - success indicator (true = success),
36   // - buffer with data (in or out),
37   // - actual length transferred.
38   using CallbackType = std::function<void(bool, const uint8_t*, int32_t)>;
39 
40   TransportRequest(std::shared_ptr<libusb_device_handle> device,
41                    CallbackType callback, const ControlTransfer& transfer);
42   TransportRequest(std::shared_ptr<libusb_device_handle> device,
43                    CallbackType callback, const DataTransfer& transfer);
44   ~TransportRequest() = default;
45 
46   uint8_t* Buffer();
47 
48   // Submit sends an asynchronous data exchange requests.
49   // Returns true only if operation was successful. At this point
50   // ownership of this structure is passed to libusb and user
51   // must not release the underlying structure.
52   bool Submit();
53 
54   // Executes corresponding callback with execution results.
55   // This is a static call to ensure that the callback being invoked
56   // can dispose of this instance.
57   static void OnTransferComplete(libusb_transfer* req);
58 
59  private:
60   std::shared_ptr<libusb_device_handle> handle_;
61   CallbackType callback_;
62   bool is_control_;
63   std::unique_ptr<libusb_transfer, void (*)(libusb_transfer*)> transfer_;
64   std::unique_ptr<uint8_t[]> buffer_;
65 
66   TransportRequest(const TransportRequest& other) = delete;
67   TransportRequest& operator=(const TransportRequest& other) = delete;
68 };
69 
70 }  // namespace usb_forward
71