5 Author: Pekka Riikonen <priikone@silcnet.org>
7 Copyright (C) 2005, 2006 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; version 2 of the License.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
20 /****h* silcutil/SILC Finite State Machine
24 * SILC FSM Interface implements a finite state machine. The FSM can be
25 * used to implement all kinds of machines and protocols. The FSM supports
26 * also threads and can be synchronized by using FSM semaphores. The FSM
27 * also supports real system threads. It is possible to create new FSM
28 * thread and then execute in real system thread, if platform supports
31 * The FSM provides semaphores because of their versatility. The FSM
32 * semaphores can be used as mutual exclusion locks to protect critical
33 * sections, and as conditional variables and signallers. The FSM
34 * semaphores can safely be used to synchronize also FSM threads that are
35 * executed in real system threads. This makes SILC FSM very effective
36 * tool to implement complex machines whether they are executed in single
37 * thread or in multiple threads.
44 /****s* silcutil/SilcFSMAPI/SilcFSM
48 * typedef struct SilcFSMObject *SilcFSM;
52 * The actual FSM context and is allocated with silc_fsm_alloc and
53 * given as argument to all silc_fsm_* functions. It is freed by
54 * silc_fsm_free function. It is also possible to use pre-allocated
55 * FSM context by using SilcFSMStruct instead of SilcFSM.
58 typedef struct SilcFSMObject *SilcFSM;
60 /****s* silcutil/SilcFSMAPI/SilcFSMStruct
64 * typedef struct SilcFSMObject SilcFSMStruct;
68 * The actual FSM context and can be used as pre-allocated FSM context,
69 * instead of SilcFSM context. This context is initialized with the
70 * silc_fsm_init function. It need not be uninitialized.
73 typedef struct SilcFSMObject SilcFSMStruct;
75 /****s* silcutil/SilcFSMAPI/SilcFSMThread
79 * typedef struct SilcFSMObject *SilcFSMThread;
83 * FSM thread context. The SILC FSM supports threads, virtual machine
84 * threads (inside FSM) and actual real system threads if platorm
85 * supports them. In a complex machine certain complex operations may
86 * be desired to execute in a thread. The SilcFSMThread is allocated
87 * by silc_fsm_thread_alloc and feed by silc_fsm_free. It is also
88 * possible to use pre-allocated thread by using SilcFSMThreadStruct
89 * instead of SilcFSMThread.
92 typedef struct SilcFSMObject *SilcFSMThread;
94 /****s* silcutil/SilcFSMAPI/SilcFSM
98 * typedef struct SilcFSMObject SilcFSMThreadStruct;
102 * FSM thread context and can be used as a pre-allocated FSM thread context,
103 * instead of SilcFSMThread context. This context is initialized with the
104 * silc_fsm_thread_init function. It need not be uninitialized.
107 typedef struct SilcFSMObject SilcFSMThreadStruct;
109 /****d* silcutil/SilcFSMAPI/SilcFSMStatus
113 * typedef enum { ... } SilcFSMStatus;
117 * Status values that the FSM state functions return. They dicatate
118 * how the machine will behave after returning from the state function.
123 SILC_FSM_CONTINUE, /* Continue immediately to next state */
124 SILC_FSM_YIELD, /* Continue to next state through scheduler */
125 SILC_FSM_WAIT, /* Wait for some async call or timeout */
126 SILC_FSM_FINISH, /* Finish state machine and call destructor
131 /****f* silcutil/SilcFSMAPI/SilcFSMDestructor
135 * typedef void (*SilcFSMDestructor)(SilcFSM fsm, void *fsm_context,
136 * void *destructor_context);
140 * The destructor callback that was set in silc_fsm_alloc or in
141 * silc_fsm_init function. It will be called when a state function
142 * returns SILC_FSM_FINISH. This function will be called through
143 * the scheduler; it will not be called immediately after the state
144 * function returns SILC_FSM_FINISH, but will be called later.
145 * The `fsm' may be freed in this function.
148 typedef void (*SilcFSMDestructor)(SilcFSM fsm, void *fsm_context,
149 void *destructor_context);
151 /****f* silcutil/SilcFSMAPI/SilcFSMThreadDestructor
155 * typedef void (*SilcFSMThreadDestructor)(SilcFSMThread thread,
156 * void *thread_context,
157 * void *destructor_context);
161 * The destructor callback that was set in silc_fsm_thread_alloc or in
162 * silc_fsm_thread_init function. It will be called when a state function
163 * returns SILC_FSM_FINISH. This function will be called through
164 * the scheduler; it will not be called immediately after the state
165 * function returns SILC_FSM_FINISH, but will be called later. The
166 * `thread' may be freed in this function.
170 * Even if the `thread' was executed in real system thread, this callback
171 * is always received in the main machine thread, not in the created
175 typedef void (*SilcFSMThreadDestructor)(SilcFSMThread thread,
176 void *thread_context,
177 void *destructor_context);
179 /****d* silcutil/SilcFSMAPI/SILC_FSM_STATE
183 * #define SILC_FSM_STATE(name)
187 * This macro is used to declare a FSM state function. The `fsm' is
188 * the SilcFSM or SilcFSMThread context, the `fsm_context' is the context
189 * given as argument to silc_fsm_alloc, silc_fsm_init, silc_fsm_thread_init,
190 * or silc_fsm_thread_alloc function. The `state_context' is the optional
191 * state specific context set with silc_fsm_set_state_context function.
195 #define SILC_FSM_STATE(name) \
196 SilcFSMStatus name(struct SilcFSMObject *fsm, void *fsm_context, \
200 /* State function callback */
201 typedef SilcFSMStatus (*SilcFSMStateCallback)(struct SilcFSMObject *fsm,
203 void *state_context);
205 /****d* silcutil/SilcFSMAPI/SILC_FSM_CALL
209 * SILC_FSM_CALL(function)
213 * Macro used to call asynchronous calls from state function. If the
214 * call is not really asynchronous then this will cause the machine to
215 * directly proceed to next state. If the call is truly asynchronous
216 * then this will set the machine to wait state. The silc_fsm_next
217 * must be called before this macro, so that the next state is set.
221 * The state function returns in this macro.
226 * silc_fsm_next(fsm, some_next_state);
227 * SILC_FSM_CALL(silc_some_async_call(server, some_callback, context));
229 * // More complex example
230 * silc_fsm_next(fsm, some_next_state);
231 * SILC_FSM_CALL((some_context->operation =
232 * silc_some_async_call(server, some_callback, context)));
235 #define SILC_FSM_CALL(function) \
237 assert(!silc_fsm_set_call(fsm, TRUE)); \
239 if (!silc_fsm_set_call(fsm, FALSE)) \
240 return SILC_FSM_CONTINUE; \
241 return SILC_FSM_WAIT; \
244 /****d* silcutil/SilcFSMAPI/SILC_FSM_CALL_CONTINUE
248 * SILC_FSM_CALL_CONTINUE(fsm)
252 * Macro used to proceed after asynchornous call. This is called in the
253 * callback of the asynchronous call to continue in the state machine.
257 * void some_callback(void *context) {
258 * SilcFSM fsm = context;
260 * // Continue to the next state
261 * SILC_FSM_CALL_CONTINUE(fsm);
265 #define SILC_FSM_CALL_CONTINUE(fsm) \
267 if (!silc_fsm_set_call(fsm, FALSE)) \
268 silc_fsm_continue(fsm); \
271 /****d* silcutil/SilcFSMAPI/SILC_FSM_CALL_CONTINUE_SYNC
275 * SILC_FSM_CALL_CONTINUE_SYNC(fsm)
279 * Macro used to proceed after asynchornous call. This is called in the
280 * callback of the asynchronous call to continue in the state machine.
281 * This continues to the next state synchronously, not through the
286 * void some_callback(void *context) {
287 * SilcFSM fsm = context;
289 * // Continue to the next state immediately
290 * SILC_FSM_CALL_CONTINUE_SYNC(fsm);
294 #define SILC_FSM_CALL_CONTINUE_SYNC(fsm) \
296 if (!silc_fsm_set_call(fsm, FALSE)) \
297 silc_fsm_continue_sync(fsm); \
300 /****d* silcutil/SilcFSMAPI/SILC_FSM_THREAD_WAIT
304 * SILC_FSM_THREAD_WAIT(thread)
308 * Macro used to wait for the `thread' to terminate. The machine or
309 * thread will be suspended while it is waiting for the thread to
314 * The state function returns in this macro.
316 * This macro is the only way to safely make sure that the thread has
317 * terminated by the time FSM continues from the waiting state. Using
318 * semaphores to signal from the thread before SILC_FSM_FINISH is returned
319 * works with normal FSM threads, but especially with real system threads
320 * it does not guarantee that the FSM won't continue before the thread has
321 * actually terminated. Usually this is not a problem, but it can be a
322 * problem if the FSM is waiting to be freed. In this case using this
323 * macro is strongly recommended.
326 #define SILC_FSM_THREAD_WAIT(thread) \
328 silc_fsm_thread_wait(fsm, thread); \
329 return SILC_FSM_WAIT; \
332 /****f* silcutil/SilcFSMAPI/silc_fsm_alloc
336 * SilcFSM silc_fsm_alloc(void *fsm_context,
337 * SilcFSMDestructor destructor,
338 * void *destructor_context,
339 * SilcSchedule schedule);
343 * Allocates SILC Finite State Machine context. The `destructor' with
344 * `destructor_context' will be called when the machines finishes. The
345 * caller must free the returned context with silc_fsm_free. The
346 * `fsm_context' is delivered to every FSM state function. The `schedule'
347 * is the caller's scheduler and the FSM will be run in the scheduler.
351 * SilcAsyncOperation silc_async_call(Callback callback, void *cb_context)
353 * SilcAsyncOperation op;
357 * // Allocate async operation so that caller can control us, like abort
358 * op = silc_async_alloc(silc_async_call_abort, NULL, ourcontext);
361 * fsm = silc_fsm_alloc(ourcontext, fsm_destructor, ourcontext,
363 * silc_fsm_start(fsm, first_state);
366 * // Return async operation for upper layer
371 SilcFSM silc_fsm_alloc(void *fsm_context,
372 SilcFSMDestructor destructor,
373 void *destructor_context,
374 SilcSchedule schedule);
376 /****f* silcutil/SilcFSMAPI/silc_fsm_init
380 * SilcBool silc_fsm_init(SilcFSM fsm,
382 * SilcFSMDestructor destructor,
383 * void *destructor_context,
384 * SilcSchedule schedule);
388 * Initializes a pre-allocated SilcFSM context. This call is equivalent
389 * to silc_fsm_alloc except that this takes the pre-allocated context
390 * as argument. The silc_fsm_free must not be called if this was called.
391 * Returns TRUE if the initialization is Ok or FALSE if error occurred.
392 * This function does not allocate any memory. The `schedule' is the
393 * caller's scheduler and the FSM will be run in the scheduler.
399 * silc_fsm_init(&fsm, application, fsm_destructor, application, schedule);
400 * silc_fsm_start(&fsm, first_state);
403 SilcBool silc_fsm_init(SilcFSM fsm,
405 SilcFSMDestructor destructor,
406 void *destructor_context,
407 SilcSchedule schedule);
409 /****f* silcutil/SilcFSMAPI/silc_fsm_thread_alloc
413 * SilcFSMThread silc_fsm_thread_alloc(SilcFSM fsm,
414 * void *thread_context,
415 * SilcFSMThreadDestructor destructor,
416 * void *destructor_context,
417 * SilcBool real_thread);
421 * Allocates FSM thread context. The thread will be executed in the
422 * FSM machine indicated by `fsm'. The caller must free the returned
423 * thread context with silc_fsm_free. If the 'real_thread' is TRUE
424 * then the thread will actually be executed in real thread, if platform
425 * supports them. The `thread_context' is delivered to every state
426 * function in the thread.
430 * Note the limitations on using `real_thread' boolean to indicate running
431 * the FSM thread in a real system thread:
433 * If the system does not support threads, then this function will revert
434 * back to normal FSM threads.
436 * If the `real_thread' is TRUE then FSM will allocate new SilcSchedule
437 * for the FSM thread. This is done because the SilcSchedule that the
438 * `fsm' use cannot be used in the thread. This is limitation in the
439 * SilcSchedule implementation. If you need scheduler in the real thread
440 * it is strongly recommended that you use the SilcSchedule that is
441 * allocated for the thread. You can retrieve the SilcSchedule from the
442 * thread using silc_fsm_get_schedule function. Note that, the allocated
443 * SilcSchedule will become invalid after the thread finishes.
445 * You may still however use the original SilcSchedule if you wish. In
446 * this case note its limitation: you may only add and/or remove tasks,
447 * tasks cannot be executed in the thread. You will need to deliver the
448 * original SilcSchedule to the thread in the `thread_context' if you wish
451 * If `real_thread' is FALSE then no limitations on what can be run in
452 * the thread exist. In this case silc_fsm_get_schedule will return
453 * the SilcSchedule that was originally given to silc_fsm_alloc or
458 * SILC_FSM_STATE(silc_foo_state)
460 * SilcFSMThread thread;
463 * // Execute the route lookup in thread
464 * thread = silc_fsm_thread_alloc(fsm, fsm_context, NULL, NULL, FALSE);
465 * silc_fsm_start(thread, silc_route_lookup_start);
467 * // Wait here for the thread to terminate. Set the state where to go
468 * // after the thread has terminated.
469 * silc_fsm_next(fsm, silc_foo_route_lookup_finished);
470 * SILC_FSM_THREAD_WAIT(thread);
474 SilcFSMThread silc_fsm_thread_alloc(SilcFSM fsm,
475 void *thread_context,
476 SilcFSMThreadDestructor destructor,
477 void *destructor_context,
478 SilcBool real_thread);
480 /****f* silcutil/SilcFSMAPI/silc_fsm_thread_init
484 * void silc_fsm_thread_init(SilcFSMThread thread,
486 * void *thread_context,
487 * SilcFSMThreadDestructor destructor,
488 * void *destructor_context,
489 * SilcBool real_thread);
493 * Initializes a pre-allocated SilcFSMThread context. This call is
494 * equivalent to silc_fsm_thread_alloc except that this takes the
495 * pre-allocated context as argument. The silc_fsm_free must not be
496 * called if this was called. If the `real_thread' is TRUE then the
497 * thread will actually be executed in real thread, if platform supports
502 * See the notes from the silc_fsm_thread_alloc.
506 * SilcFSMThreadStruct thread;
508 * silc_fsm_thread_init(&thread, fsm, application, NULL, NULL, FALSE);
509 * silc_fsm_start(&thread, first_state);
512 void silc_fsm_thread_init(SilcFSMThread thread,
514 void *thread_context,
515 SilcFSMThreadDestructor destructor,
516 void *destructor_context,
517 SilcBool real_thread);
519 /****f* silcutil/SilcFSMAPI/silc_fsm_free
523 * void silc_fsm_free(void *fsm);
527 * Free the SILC FSM context that was allocated with silc_fsm_alloc,
528 * or free the SILC FSM thread context that was allocated with
529 * silc_fsm_thread_alloc. This function is used with both SilcFSM
530 * and SilcFSMThread contexts.
534 * When freeing FSM, it must not have any active threads.
537 void silc_fsm_free(void *fsm);
539 /****f* silcutil/SilcFSMAPI/silc_fsm_start
543 * void silc_fsm_start(void *fsm, SilcFSMStateCallback start_state);
547 * This function must be called after the SILC FSM context was created.
548 * This actually starts the state machine. Note that, the machine is
549 * started later after this function returns. The `start_state' is the
550 * state where the machine or thread is started. This function is used
551 * with both SilcFSM and SilcFSMThread contexts.
557 * fsm = silc_fsm_alloc(context, destructor, context, schedule);
558 * silc_fsm_start(fsm, first_state);
561 void silc_fsm_start(void *fsm, SilcFSMStateCallback start_state);
563 /****f* silcutil/SilcFSMAPI/silc_fsm_start_sync
567 * void silc_fsm_start_sync(void *fsm, SilcFSMStateCallback start_state);
571 * This function is same as silc_fsm_start, except that the FSM will
572 * be started immediately inside this function. After this function
573 * returns the `start_state' has already been executed. If the machine
574 * is completely synchronous (no waiting used in the machine) then
575 * the machine will have finished once this function returns. Also
576 * note that if the machine is completely synchronous the destructor
577 * will also be called from inside this function. This function is used
578 * with both SilcFSM and SilcFSMThread contexts.
581 void silc_fsm_start_sync(void *fsm, SilcFSMStateCallback start_state);
583 /****f* silcutil/SilcFSMAPI/silc_fsm_next
587 * void silc_fsm_next(void *fsm, SilcFSMStateCallback next_state);
591 * Set the next state to be executed. If the state function that
592 * call this function returns SILC_FSM_CONTINUE, the `next_state'
593 * will be executed immediately. If it returns SILC_FSM_YIELD it
594 * yields the thread and the `next_state' will be run after other
595 * threads have run first. This function must always be used to set
596 * the next state in the machine or thread. This function is used
597 * with both SilcFSM and SilcFSMThread contexts.
601 * // Move to next state
602 * silc_fsm_next(fsm, next_state);
603 * return SILC_FSM_CONTINUE;
606 void silc_fsm_next(void *fsm, SilcFSMStateCallback next_state);
608 /****f* silcutil/SilcFSMAPI/silc_fsm_next_later
612 * void silc_fsm_next_later(void *fsm, SilcFSMStateCallback next_state,
613 * SilcUInt32 seconds, SilcUInt32 useconds);
617 * Set the next state to be executed later, at the specified time.
618 * The SILC_FSM_WAIT must be returned in the state function if this
619 * function is called. If any other state is returned machine operation
620 * is undefined. The machine or thread will move to `next_state' after
621 * the specified timeout. This function is used with both SilcFSM and
622 * SilcFSMThread contexts.
626 * If both `seconds' and `useconds' are 0, the effect is same as calling
627 * silc_fsm_next function, and SILC_FSM_CONTINUE must be returned.
631 * // Move to next state after 10 seconds
632 * silc_fsm_next_later(fsm, next_state, 10, 0);
633 * return SILC_FSM_WAIT;
636 void silc_fsm_next_later(void *fsm, SilcFSMStateCallback next_state,
637 SilcUInt32 seconds, SilcUInt32 useconds);
639 /****f* silcutil/SilcFSMAPI/silc_fsm_continue
643 * void silc_fsm_continue(void *fsm);
647 * Continues in the state machine from a SILC_FSM_WAIT state. This can
648 * be called from outside waiting FSM to continue to the next state.
649 * This function can be used instead of SILC_FSM_CALL_CONTINUE macro
650 * in case the SILC_FSM_CALL was not used. This must not be used if
651 * SILC_FSM_CALL was used. This function is used with both SilcFSM and
652 * SilcFSMThread contexts.
655 void silc_fsm_continue(void *fsm);
657 /****f* silcutil/SilcFSMAPI/silc_fsm_continue_sync
661 * void silc_fsm_continue_sync(void *fsm);
665 * Continues immediately in the state machine from a SILC_FSM_WAIT state.
666 * This can be called from outside waiting FSM to immediately continue to
667 * the next state. This function can be used instead of the
668 * SILC_FSM_CALL_CONTINUE_SYNC macro in case the SILC_FSM_CALL was not used.
669 * This must not be used if SILC_FSM_CALL was used. This function is used
670 * with both SilcFSM and SilcFSMThread contexts.
673 void silc_fsm_continue_sync(void *fsm);
675 /****f* silcutil/SilcFSMAPI/silc_fsm_set_context
679 * void silc_fsm_set_context(void *fsm, void *fsm_context);
683 * Set new context for the `fsm'. This function can be used to change
684 * the context inside the `fsm', if needed. This function is used with
685 * both SilcFSM and SilcFSMThread contexts. The context is the
686 * `fsm_context' in the state function (SILC_FSM_STATE).
689 void silc_fsm_set_context(void *fsm, void *fsm_context);
691 /****f* silcutil/SilcFSMAPI/silc_fsm_get_context
695 * void *silc_fsm_get_context(void *fsm);
699 * Returns the context associated with the `fsm'. It is the context that
700 * was given to silc_fsm_alloc, silc_fsm_init, silc_fsm_thread_alloc or
701 * silc_fsm_thread_init. This function is used with both SilcFSM and
702 * SilcFSMThread contexts.
705 void *silc_fsm_get_context(void *fsm);
707 /****f* silcutil/SilcFSMAPI/silc_fsm_set_state_context
711 * void silc_fsm_set_state_context(void *fsm, void *state_context);
715 * Set's a state specific context for the `fsm'. This function can be
716 * used to change the state context inside the `fsm', if needed. This
717 * function is used with both SilcFSM and SilcFSMThread contexts. The
718 * context is the `state_context' in the state function (SILC_FSM_STATE).
721 void silc_fsm_set_state_context(void *fsm, void *state_context);
723 /****f* silcutil/SilcFSMAPI/silc_fsm_get_state_context
727 * void *silc_fsm_get_state_context(void *fsm);
731 * Returns the state context associated with the `fsm'. It is the context
732 * that was set with silc_fsm_set_state_context function. This function
733 * is used with both SilcFSM and SilcFSMThread contexts.
736 void *silc_fsm_get_state_context(void *fsm);
738 /****f* silcutil/SilcFSMAPI/silc_fsm_get_schedule
742 * SilcSchedule silc_fsm_get_schedule(void *fsm);
746 * Returns the SilcSchedule that has been associated with the `fsm'.
747 * If caller needs scheduler it may retrieve it with this function. This
748 * function is used with both SilcFSM and SilcFSMThread contexts.
750 * If the `fsm' is thread and real system threads are being used, and this
751 * is called from the thread, it will return the SilcSchedule that was
752 * allocated by the FSM for the thread. It is strongly recommended to
753 * use this SilcSchedule if you are using real threads, and you need
754 * scheduler in the thread. Note that, once the thread finishes the
755 * returned SilcSchedule becomes invalid.
757 * In other times this returns the SilcSchedule pointer that was given
758 * to silc_fsm_alloc or silc_fsm_init.
761 SilcSchedule silc_fsm_get_schedule(void *fsm);
763 /****f* silcutil/SilcFSMAPI/silc_fsm_get_machine
767 * SilcFSM silc_fsm_get_machine(SilcFSMThread thread);
771 * Returns the machine from the FSM thread indicated by `thread'.
774 SilcFSM silc_fsm_get_machine(SilcFSMThread thread);
779 /****s* silcutil/SilcFSMAPI/SilcFSMSema
783 * typedef struct SilcFSMSemaObject *SilcFSMSema;
787 * The FSM semaphore context allocated with silc_fsm_sema_alloc. The
788 * caller must free it with silc_fsm_sema_free. It is also possible
789 * to use pre-allocated SilcFSMSemaStruct instead of SilcFSMSema context.
792 typedef struct SilcFSMSemaObject *SilcFSMSema;
794 /****s* silcutil/SilcFSMAPI/SilcFSMSemaStruct
798 * typedef struct SilcFSMSemaObject SilcFSMSemaStruct;
802 * The FSM semaphore context that can be used as pre-allocated context.
803 * It is initialized with silc_fsm_sema_init. It need not be
807 typedef struct SilcFSMSemaObject SilcFSMSemaStruct;
809 /****f* silcutil/SilcFSMAPI/silc_fsm_sema_alloc
813 * SilcFSMSema silc_fsm_sema_alloc(SilcFSM fsm, SilcUInt32 value);
817 * Allocates FSM semaphore with initial value of `value'. Semaphores are
818 * counters for resources shared between machine and threads. Semaphores
819 * can be waited until the semaphore value is non-zero. The FSM will be
820 * suspended when waiting for semaphore. When the semaphore is incremented
821 * all that are waiting for the semaphore will be signalled and awaken.
823 * Semaphores can be used to wait for example when thread terminates, or
824 * when thread moves into a specific state, or to protect critical
825 * sections. The FSM semaphores can be used also in FSM threads that are
826 * executed in real system threads.
828 * Use the macros SILC_FSM_SEMA_WAIT and SILC_FSM_SEMA_TIMEDWAIT to wait
829 * for semaphore. Use the SILC_FSM_SEMA_POST macro to increment the
830 * counter and wake up all waiters.
833 SilcFSMSema silc_fsm_sema_alloc(SilcFSM fsm, SilcUInt32 value);
835 /****f* silcutil/SilcFSMAPI/silc_fsm_sema_init
839 * void silc_fsm_sema_init(SilcFSMSema sema, SilcFSM fsm, SilcUInt32 value);
843 * Initializes a pre-allocates semaphore context. This call is
844 * equivalent to silc_fsm_sema_alloc except this use the pre-allocated
845 * context. This fuction does not allocate any memory.
848 void silc_fsm_sema_init(SilcFSMSema sema, SilcFSM fsm, SilcUInt32 value);
850 /****f* silcutil/SilcFSMAPI/silc_fsm_sema_free
854 * void silc_fsm_sema_free(SilcFSMSema sema);
858 * Free the semaphore allocated by silc_fsm_sema_alloc function.
861 void silc_fsm_sema_free(SilcFSMSema sema);
863 /****d* silcutil/SilcFSMAPI/SILC_FSM_SEMA_WAIT
867 * SILC_FSM_SEMA_WAIT(semaphore)
871 * Macro used to wait for the `semaphore' to become non-zero. The
872 * machine will be suspended while it is waiting for the semaphore.
873 * This macro can only be used in FSM state functions. When the
874 * semaphore is signalled the FSM will re-enter the current state (or
875 * state that was set with silc_fsm_next before waiting).
879 * // Signalling example
880 * ctx->async_sema = silc_fsm_sema_alloc(fsm, 0);
883 * SILC_FSM_STATE(silc_foo_state)
887 * // Wait here for async call to complete
888 * SILC_FSM_SEMA_WAIT(ctx->async_sema);
890 * // Async call completed
891 * if (ctx->async_success == FALSE)
896 * // Mutual exclusion example
897 * ctx->lock = silc_fsm_sema_alloc(fsm, 1);
900 * SILC_FSM_STATE(silc_foo_state)
903 * SILC_FSM_SEMA_WAIT(ctx->lock);
904 * very critical stuff...
905 * SILC_FSM_SEMA_POST(ctx->lock);
910 #define SILC_FSM_SEMA_WAIT(sema) \
912 if (silc_fsm_sema_wait(sema, fsm) == 0) \
913 return SILC_FSM_WAIT; \
916 /****d* silcutil/SilcFSMAPI/SILC_FSM_SEMA_TIMEDWAIT
920 * SILC_FSM_SEMA_TIMEDWAIT(semaphore, seconds, useconds, timedout)
924 * Macro used to wait for the `semaphore' to become non-zero, or until
925 * the timeout specified by `seconds' and `useconds' has elapsed. If
926 * the timeout occurs before the semaphore becomes non-zero, the machine
927 * will wakeup. The `timedout' is SilcBool pointer and if it is
928 * non-NULL indication of whether timeout occurred or not is saved to
929 * the pointer. This macro can only be used in FSM state functions.
930 * When the semaphore is signalled or timedout the FSM will re-enter
931 * the current state (or state that was set with silc_fsm_next before
936 * SILC_FSM_STATE(silc_foo_state)
941 * // Wait here for async call to complete, or 10 seconds for timeout
942 * SILC_FSM_SEMA_TIMEDWAIT(ctx->async_sema, 10, 0, &timedout);
944 * // See if timeout occurred
945 * if (timedout == TRUE)
948 * // Async call completed
949 * if (ctx->async_success == FALSE)
955 #define SILC_FSM_SEMA_TIMEDWAIT(sema, seconds, useconds, ret_to) \
957 if (silc_fsm_sema_timedwait(sema, fsm, seconds, useconds, ret_to) == 0) \
958 return SILC_FSM_WAIT; \
961 /****f* silcutil/SilcFSMAPI/SILC_FSM_SEMA_POST
965 * SILC_FSM_SEMA_POST(semaphore)
969 * Increases the semaphore counter and awakens everybody that are
970 * waiting for this semaphore. This macro never blocks. It can be
971 * safely called at any place in state function and in asynchronous
972 * callbacks or other functions.
976 * SILC_FSM_STATE(silc_foo_async_completion)
980 * // Notify all waiters
981 * ctx->async_success = TRUE;
982 * SILC_FSM_SEMA_POST(ctx->async_sema);
987 #define SILC_FSM_SEMA_POST(sema) \
989 silc_fsm_sema_post(sema); \
992 #include "silcfsm_i.h"
994 #endif /* SILCFSM_H */