#ifndef UC_IOMUX_WAKE_H_
#define UC_IOMUX_WAKE_H_

#include <pthread.h>
#include "iomux.h"

#ifdef __cplusplus
extern "C" {
#endif
struct IOMuxWaker;
typedef void (*uc_waker_cb)(struct IOMuxWaker *wk);

/** These are primitives to wake up an IOMux.
 * An IOMux event loop can be woken up from e.g. an unix signal handler
 * or another thread. The IOMuxWaker itself is not thread safe, it's members
 * must not be accessed from anything other than the loop it's connected to.
 * Only uc_iomux_waker_signal() can be called from another thread/signal handler
 * than the IOMux it's connected to.
 * 
 * Note that several signals to wake up a loop can get merged, the callback
 * handler can be called only once for several signals.
 */
struct IOMuxWaker {
    //private fields
    int fds[2];
    struct IOMuxFD read_fd;
    uc_waker_cb wake_cb;

    //public fields
    struct IOMux *mux;
    void *cookie;
};

/** Initialize an IOMuxWaker.
 * Must be called from the thread running the IOMux.
 *
 * @mux the IOMux to be woken up.
 * @wk the waker to initialize
 * @cb callback to invoke in the mux when signalled
 * @return 0 on success, errno value if initializing fails
 */
int uc_iomux_waker_init(struct IOMux *mux, struct IOMuxWaker *wk, uc_waker_cb cb);

/** Destroy an IOMuxWaker.
 *  Must previously been successfully initialized.
 *  Must be called from the thread running the IOMux.
 *  Care must be taken so the IOMuxWaker is destroyed
 *  without race conditions with a thread that wants to _signal the
 *  waker.
 * 
 * @param wk
 * @return 0 on success, errno on failure (Things are seriously
 *         wrong if this fails)
 */
int uc_iomux_waker_destroy(struct IOMuxWaker *wk);

/** Signal an IOMux to wake up and run its callback handler.
 * Is async signal safe.
 * Several signals in a short time may result in the callback
 * being run only once.
 * 
 * @param wk 
 * @return 0 on success, errno on failure (Things are seriously
 *         wrong if this fails)
 */
int uc_iomux_waker_signal(struct IOMuxWaker *wk);

#ifdef __cplusplus
}
#endif

#endif