#ifndef TRANSPORT_INTERNAL_H
#define TRANSPORT_INTERNAL_H

/**
 * @file
 *
 * The internal interface for transport implementations.
 */ 
#include "transport.h"

/**
 * Method table for implementation stuff
 */
struct transport_methods {
    /** For transport_read() */
    err_t (*read) (transport_t *transport, void *buf, size_t *len, error_t *err);

    /** For transport_write() */
    err_t (*write) (transport_t *transport, const void *buf, size_t *len, error_t *err);

    /** Release the transport's state, but not the transport itself */
    void (*destroy) (transport_t *transport);
};

/**
 * The definition of a transport type
 */
struct transport_type {
    /** Method table */
    struct transport_methods methods;
};

/**
 * The base transport type
 */
struct transport {
    /** The type info, or NULL if not yet bound */
    const struct transport_type *type;

    /** User info */
    struct transport_info info;
};

/**
 * Bind the given transport to the given type with the given user info.
 *
 * It is a bug to call this with a transport that is already bound.
 */
void transport_bind (transport_t *transport, const struct transport_type *type, const struct transport_info *info);

/**
 * Check the type of the transport, and return the transport as a void* suitable for casting to the appropriate struct
 * for the type.
 *
 * It is a bug to call this with a transport of a different type.
 */
void* transport_check (transport_t *transport, const struct transport_type *type);


#endif /* TRANSPORT_INTERNAL_H */