/*
 * Copyright 2005-2008 Stephan Aßmus <superstippi@gmx.de>. All rights reserved.
 * Distributed under the terms of the MIT license.
 */
#ifndef USB_DEVICE_MONITOR_H
#define USB_DEVICE_MONITOR_H


// This class is designed to work with the generic USB input device driver
// the driver creates an entry in /dev/input/???
// clients can open and read from the device file, the driver will than
// block on waiting for an interrupt transfer (timeout is 500 ms) and write
// the received data to the supplied buffer. In front of the buffer, it will
// write vendorID, productID and maxPacketSize, so you can read from the file
// with a buffer of just enough size to contain these fields, in this case, no
// interrupt transfer will be triggered, and the client can then configure itself
// with a more appropriate setup.

#include <SupportDefs.h>

class BFile;
class BString;

class DeviceReader {
 public:
                                                                DeviceReader();
        virtual                                         ~DeviceReader();

                                                                // initializes the object
                                                                // by trying to read from the supplied device file
                                                                // on success (B_OK), all member variables will be set
                                                                // and the object is ready for operation
                                                                // on failure, a hopefully meaningful error is returned
        virtual status_t                        SetTo(const char* path);

        virtual status_t                        InitCheck() const;
        
                        const char*                     DevicePath() const;
                        BFile*                          DeviceFile() const;

                        // query the device for information
                        uint16                          VendorID() const;
                        uint16                          ProductID() const;

                        size_t                          MaxPacketSize() const;

                        // trigger an interrupt transfer and write the data in the buffer
                        // it should be save to call this function with
                        // size != MaxPacketSize, remaining bytes will be zero'd out
                        ssize_t                         ReadData(uint8* data,
                                                                        const size_t size) const;

 protected:
                        void                            _Unset();

                        char*                           fDevicePath;
                        BFile*                          fDeviceFile;

                        uint16                          fVendorID;
                        uint16                          fProductID;
                        size_t                          fMaxPacketSize;
};
#endif // USB_DEVICE_MONITOR_H