Return to watcher.h CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / strongswan / src / libstrongswan / processing

Annotation of embedaddon/strongswan/src/libstrongswan/processing/watcher.h, revision 1.1.1.1

1.1       misho       1: /*
                      2:  * Copyright (C) 2013 Martin Willi
                      3:  * Copyright (C) 2013 revosec AG
                      4:  *
                      5:  * This program is free software; you can redistribute it and/or modify it
                      6:  * under the terms of the GNU General Public License as published by the
                      7:  * Free Software Foundation; either version 2 of the License, or (at your
                      8:  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
                      9:  *
                     10:  * This program is distributed in the hope that it will be useful, but
                     11:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     12:  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
                     13:  * for more details.
                     14:  */
                     15: 
                     16: /**
                     17:  * @defgroup watcher watcher
                     18:  * @{ @ingroup processor
                     19:  */
                     20: 
                     21: #ifndef WATCHER_H_
                     22: #define WATCHER_H_
                     23: 
                     24: typedef struct watcher_t watcher_t;
                     25: typedef enum watcher_event_t watcher_event_t;
                     26: typedef enum watcher_state_t watcher_state_t;
                     27: 
                     28: #include <library.h>
                     29: 
                     30: /**
                     31:  * Callback function to register for file descriptor events.
                     32:  *
                     33:  * The callback is executed asynchronously using a thread from the pool.
                     34:  * Monitoring of fd is temporarily suspended to avoid additional events while
                     35:  * it is processed asynchronously. To allow concurrent events, one can quickly
                     36:  * process it (using a read/write) and return from the callback. This will
                     37:  * re-enable the event, while the data read can be processed in another
                     38:  * asynchronous job.
                     39:  *
                     40:  * On Linux, even if select() marks an FD as "ready", a subsequent read/write
                     41:  * can block. It is therefore highly recommended to use non-blocking I/O
                     42:  * and handle EAGAIN/EWOULDBLOCK gracefully.
                     43:  *
                     44:  * @param data         user data passed during registration
                     45:  * @param fd           file descriptor the event occurred on
                     46:  * @param event                type of event
                     47:  * @return                     TRUE to keep watching event, FALSE to unregister fd for event
                     48:  */
                     49: typedef bool (*watcher_cb_t)(void *data, int fd, watcher_event_t event);
                     50: 
                     51: /**
                     52:  * What events to watch for a file descriptor.
                     53:  */
                     54: enum watcher_event_t {
                     55:        WATCHER_READ = (1<<0),
                     56:        WATCHER_WRITE = (1<<1),
                     57:        WATCHER_EXCEPT = (1<<2),
                     58: };
                     59: 
                     60: /**
                     61:  * State the watcher currently is in
                     62:  */
                     63: enum watcher_state_t {
                     64:        /** no watcher thread running or queued */
                     65:        WATCHER_STOPPED = 0,
                     66:        /** a job has been queued for watching, but not yet started */
                     67:        WATCHER_QUEUED,
                     68:        /** a watcher thread is active, dispatching socket events */
                     69:        WATCHER_RUNNING,
                     70: };
                     71: 
                     72: /**
                     73:  * Watch multiple file descriptors using select().
                     74:  */
                     75: struct watcher_t {
                     76: 
                     77:        /**
                     78:         * Start watching a new file descriptor.
                     79:         *
                     80:         * Multiple callbacks can be registered for the same file descriptor, and
                     81:         * all of them get notified. Such callbacks are executed concurrently.
                     82:         *
                     83:         * @param fd            file descriptor to start watching
                     84:         * @param events        ORed set of events to watch
                     85:         * @param cb            callback function to invoke on events
                     86:         * @param data          data to pass to cb()
                     87:         */
                     88:        void (*add)(watcher_t *this, int fd, watcher_event_t events,
                     89:                                watcher_cb_t cb, void *data);
                     90: 
                     91:        /**
                     92:         * Stop watching a previously registered file descriptor.
                     93:         *
                     94:         * This call blocks until any active callback for this FD returns. All
                     95:         * callbacks registered for that FD get unregistered.
                     96:         *
                     97:         * @param fd            file descriptor to stop watching
                     98:         */
                     99:        void (*remove)(watcher_t *this, int fd);
                    100: 
                    101:        /**
                    102:         * Get the current watcher state
                    103:         *
                    104:         * @return                      currently active watcher state
                    105:         */
                    106:        watcher_state_t (*get_state)(watcher_t *this);
                    107: 
                    108:        /**
                    109:         * Destroy a watcher_t.
                    110:         */
                    111:        void (*destroy)(watcher_t *this);
                    112: };
                    113: 
                    114: /**
                    115:  * Create a watcher instance.
                    116:  *
                    117:  * @return             watcher
                    118:  */
                    119: watcher_t *watcher_create();
                    120: 
                    121: #endif /** WATCHER_H_ @}*/