122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
/*
|
|
* Copyright (C) 2013 Martin Willi
|
|
* Copyright (C) 2013 revosec AG
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* for more details.
|
|
*/
|
|
|
|
/**
|
|
* @defgroup watcher watcher
|
|
* @{ @ingroup processor
|
|
*/
|
|
|
|
#ifndef WATCHER_H_
|
|
#define WATCHER_H_
|
|
|
|
typedef struct watcher_t watcher_t;
|
|
typedef enum watcher_event_t watcher_event_t;
|
|
typedef enum watcher_state_t watcher_state_t;
|
|
|
|
#include <library.h>
|
|
|
|
/**
|
|
* Callback function to register for file descriptor events.
|
|
*
|
|
* The callback is executed asynchronously using a thread from the pool.
|
|
* Monitoring of fd is temporarily suspended to avoid additional events while
|
|
* it is processed asynchronously. To allow concurrent events, one can quickly
|
|
* process it (using a read/write) and return from the callback. This will
|
|
* re-enable the event, while the data read can be processed in another
|
|
* asynchronous job.
|
|
*
|
|
* On Linux, even if select() marks an FD as "ready", a subsequent read/write
|
|
* can block. It is therefore highly recommended to use non-blocking I/O
|
|
* and handle EAGAIN/EWOULDBLOCK gracefully.
|
|
*
|
|
* @param data user data passed during registration
|
|
* @param fd file descriptor the event occurred on
|
|
* @param event type of event
|
|
* @return TRUE to keep watching event, FALSE to unregister fd for event
|
|
*/
|
|
typedef bool (*watcher_cb_t)(void *data, int fd, watcher_event_t event);
|
|
|
|
/**
|
|
* What events to watch for a file descriptor.
|
|
*/
|
|
enum watcher_event_t {
|
|
WATCHER_READ = (1<<0),
|
|
WATCHER_WRITE = (1<<1),
|
|
WATCHER_EXCEPT = (1<<2),
|
|
};
|
|
|
|
/**
|
|
* State the watcher currently is in
|
|
*/
|
|
enum watcher_state_t {
|
|
/** no watcher thread running or queued */
|
|
WATCHER_STOPPED = 0,
|
|
/** a job has been queued for watching, but not yet started */
|
|
WATCHER_QUEUED,
|
|
/** a watcher thread is active, dispatching socket events */
|
|
WATCHER_RUNNING,
|
|
};
|
|
|
|
/**
|
|
* Watch multiple file descriptors using select().
|
|
*/
|
|
struct watcher_t {
|
|
|
|
/**
|
|
* Start watching a new file descriptor.
|
|
*
|
|
* Multiple callbacks can be registered for the same file descriptor, and
|
|
* all of them get notified. Such callbacks are executed concurrently.
|
|
*
|
|
* @param fd file descriptor to start watching
|
|
* @param events ORed set of events to watch
|
|
* @param cb callback function to invoke on events
|
|
* @param data data to pass to cb()
|
|
*/
|
|
void (*add)(watcher_t *this, int fd, watcher_event_t events,
|
|
watcher_cb_t cb, void *data);
|
|
|
|
/**
|
|
* Stop watching a previously registered file descriptor.
|
|
*
|
|
* This call blocks until any active callback for this FD returns. All
|
|
* callbacks registered for that FD get unregistered.
|
|
*
|
|
* @param fd file descriptor to stop watching
|
|
*/
|
|
void (*remove)(watcher_t *this, int fd);
|
|
|
|
/**
|
|
* Get the current watcher state
|
|
*
|
|
* @reutrn currently active watcher state
|
|
*/
|
|
watcher_state_t (*get_state)(watcher_t *this);
|
|
|
|
/**
|
|
* Destroy a watcher_t.
|
|
*/
|
|
void (*destroy)(watcher_t *this);
|
|
};
|
|
|
|
/**
|
|
* Create a watcher instance.
|
|
*
|
|
* @return watcher
|
|
*/
|
|
watcher_t *watcher_create();
|
|
|
|
#endif /** WATCHER_H_ @}*/
|