gyro_board/src/libusb-driver/libusb_wrap.h

#ifndef LIBUSB_H_
#define LIBUSB_H_

#include <libusb-1.0/libusb.h>

#include "aos/common/macros.h"
#include "aos/common/time.h"

class LibUSBDeviceHandle;
namespace libusb {
class Transfer;
class IsochronousTransfer;
}

class LibUSB {
 public:
  explicit LibUSB();
  ~LibUSB();

  // Return a device handle or NULL with the correct VID and PID.
  LibUSBDeviceHandle *FindDeviceWithVIDPID(
      int vid, int pid);

  void HandleEvents();

 private:
  libusb_context *ctx_;

  DISALLOW_COPY_AND_ASSIGN(LibUSB);
};

class LibUSBDeviceHandle {
 public:
  virtual ~LibUSBDeviceHandle();
  // Transfers data using an interrupt transfer.
  int interrupt_transfer(unsigned char endpoint, unsigned char *data,
                         int length, int *transferred, unsigned int timeout);

  // Transfers data using a bulk transfer.
  int bulk_transfer(unsigned char endpoint, unsigned char *data,
                    int length, int *transferred, unsigned int timeout);

 private:
  friend class LibUSB; // For constructor
  friend class libusb::Transfer;  // for access to dev_handle_
  friend class libusb::IsochronousTransfer;  // for access to dev_handle_
  // Takes ownership of the device handle and frees it when destructed.
  explicit LibUSBDeviceHandle(libusb_device_handle *dev_handle);
  libusb_device_handle *dev_handle_;

 DISALLOW_COPY_AND_ASSIGN(LibUSBDeviceHandle);
};

// TODO(brians): move everything in here
namespace libusb {

// Wraps a libusb_transfer*.
// Represents an asynchronous transfer.
// Only designed to support interrupt and bulk transfers because they are very
// similar and simple.
class Transfer {
 public:
  Transfer(size_t data_length,
           void (*callback)(Transfer *, void *),
           void *user_data,
           int num_iso_packets = 0);
  ~Transfer();

  void FillInterrupt(LibUSBDeviceHandle *device,
                     unsigned char endpoint,
                     unsigned int timeout);

  void Submit();
  void Cancel();

  libusb_transfer_status status() { return transfer_->status; }
  virtual int read_bytes() { return transfer_->actual_length; }

  const uint8_t *data() { return data_; }

 protected:
  static void StaticTransferCallback(libusb_transfer *self) {
    static_cast<Transfer *>(self->user_data)->TransferCallback();
  }

 protected:
  libusb_transfer *const transfer_;

  uint8_t *const data_;
  size_t data_length_;

 private:
  void TransferCallback();

  void (*const callback_)(Transfer *, void *);
  void *const user_data_;

  DISALLOW_COPY_AND_ASSIGN(Transfer);
};

// TODO(brians): Make this actually work for num_packets != 1.
class IsochronousTransfer : public Transfer {
 public:
  IsochronousTransfer(size_t packet_length,
                      int num_packets,
                      void (*callback)(Transfer *, void *),
                      void *user_data);

  void FillIsochronous(LibUSBDeviceHandle *device,
                       unsigned char endpoint,
                       const ::aos::time::Time &timeout);

  virtual int read_bytes() {
    return transfer_->iso_packet_desc[0].actual_length;
  }

 private:
  const int num_packets_;
};

}  // namespace libusb

#endif  // LIBUSB_H_