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3 (C) 2009, 2011 Christian Grothoff (and other contributing authors)
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22 * @file include/gnunet_scheduler_lib.h
23 * @brief API to schedule computations using continuation passing style
24 * @author Christian Grothoff
27 #ifndef GNUNET_SCHEDULER_LIB_H
28 #define GNUNET_SCHEDULER_LIB_H
33 #if 0 /* keep Emacsens' auto-indent happy */
39 * Opaque reference to a task.
41 typedef unsigned long long GNUNET_SCHEDULER_TaskIdentifier;
45 * Constant used to indicate that the scheduled
46 * task has no others as prerequisites.
48 #define GNUNET_SCHEDULER_NO_TASK ((GNUNET_SCHEDULER_TaskIdentifier) 0)
51 * Reasons why the schedule may have triggered
54 enum GNUNET_SCHEDULER_Reason
57 * This is the very first task run during startup.
59 GNUNET_SCHEDULER_REASON_STARTUP = 0,
62 * We are shutting down and are running all shutdown-related tasks
63 * (regardless of timeout, etc.).
65 GNUNET_SCHEDULER_REASON_SHUTDOWN = 1,
68 * The specified timeout has expired.
69 * (also set if the delay given was 0).
71 GNUNET_SCHEDULER_REASON_TIMEOUT = 2,
74 * The reading socket is ready.
76 GNUNET_SCHEDULER_REASON_READ_READY = 4,
79 * The writing socket is ready.
81 GNUNET_SCHEDULER_REASON_WRITE_READY = 8,
84 * The prerequisite task is done.
86 GNUNET_SCHEDULER_REASON_PREREQ_DONE = 16
91 * Valid task priorities. Use these, do not
92 * pass random integers!
94 enum GNUNET_SCHEDULER_Priority
97 * Run with the same priority as the current job.
99 GNUNET_SCHEDULER_PRIORITY_KEEP = 0,
102 * Run when otherwise idle.
104 GNUNET_SCHEDULER_PRIORITY_IDLE = 1,
107 * Run as background job (higher than idle,
108 * lower than default).
110 GNUNET_SCHEDULER_PRIORITY_BACKGROUND = 2,
113 * Run with the default priority (normal
114 * P2P operations). Higher than BACKGROUND.
116 GNUNET_SCHEDULER_PRIORITY_DEFAULT = 3,
119 * Run with high priority (important requests).
120 * Higher than DEFAULT.
122 GNUNET_SCHEDULER_PRIORITY_HIGH = 4,
125 * Run with priority for interactive tasks.
126 * Higher than "HIGH".
128 GNUNET_SCHEDULER_PRIORITY_UI = 5,
131 * Run with priority for urgent tasks. Use
132 * for things like aborts and shutdowns that
133 * need to preempt "UI"-level tasks.
136 GNUNET_SCHEDULER_PRIORITY_URGENT = 6,
139 * This is an internal priority level that is only used for tasks
140 * that are being triggered due to shutdown (they have automatically
141 * highest priority). User code must not use this priority level
142 * directly. Tasks run with this priority level that internally
143 * schedule other tasks will see their original priority level
144 * be inherited (unless otherwise specified).
146 GNUNET_SCHEDULER_PRIORITY_SHUTDOWN = 7,
149 * Number of priorities (must be the last priority).
150 * This priority must not be used by clients.
152 GNUNET_SCHEDULER_PRIORITY_COUNT = 8
155 #include "gnunet_time_lib.h"
156 #include "gnunet_network_lib.h"
160 * Context information passed to each scheduler task.
162 struct GNUNET_SCHEDULER_TaskContext
165 * Reason why the task is run now
167 enum GNUNET_SCHEDULER_Reason reason;
170 * Set of file descriptors ready for reading;
171 * note that additional bits may be set
172 * that were not in the original request
174 const struct GNUNET_NETWORK_FDSet *read_ready;
177 * Set of file descriptors ready for writing;
178 * note that additional bits may be set
179 * that were not in the original request.
181 const struct GNUNET_NETWORK_FDSet *write_ready;
187 * Signature of the main function of a task.
190 * @param tc context information (why was this task triggered now)
192 typedef void (*GNUNET_SCHEDULER_Task) (void *cls,
193 const struct GNUNET_SCHEDULER_TaskContext
198 * Signature of the select function used by the scheduler.
199 * GNUNET_NETWORK_socket_select matches it.
202 * @param rfds set of sockets to be checked for readability
203 * @param wfds set of sockets to be checked for writability
204 * @param efds set of sockets to be checked for exceptions
205 * @param timeout relative value when to return
206 * @return number of selected sockets, GNUNET_SYSERR on error
208 typedef int (*GNUNET_SCHEDULER_select) (void *cls,
209 struct GNUNET_NETWORK_FDSet * rfds,
210 struct GNUNET_NETWORK_FDSet * wfds,
211 struct GNUNET_NETWORK_FDSet * efds,
212 struct GNUNET_TIME_Relative timeout);
214 * Initialize and run scheduler. This function will return when all
215 * tasks have completed. On systems with signals, receiving a SIGTERM
216 * (and other similar signals) will cause "GNUNET_SCHEDULER_shutdown"
217 * to be run after the active task is complete. As a result, SIGTERM
218 * causes all active tasks to be scheduled with reason
219 * "GNUNET_SCHEDULER_REASON_SHUTDOWN". (However, tasks added
220 * afterwards will execute normally!). Note that any particular
221 * signal will only shut down one scheduler; applications should
222 * always only create a single scheduler.
224 * @param task task to run first (and immediately)
225 * @param task_cls closure of task
228 GNUNET_SCHEDULER_run (GNUNET_SCHEDULER_Task task, void *task_cls);
232 * Request the shutdown of a scheduler. Marks all currently
233 * pending tasks as ready because of shutdown. This will
234 * cause all tasks to run (as soon as possible, respecting
235 * priorities and prerequisite tasks). Note that tasks
236 * scheduled AFTER this call may still be delayed arbitrarily.
239 GNUNET_SCHEDULER_shutdown ();
243 * Get information about the current load of this scheduler. Use this
244 * function to determine if an elective task should be added or simply
245 * dropped (if the decision should be made based on the number of
246 * tasks ready to run).
248 * * @param p priority-level to query, use KEEP to query the level
249 * of the current task, use COUNT to get the sum over
250 * all priority levels
251 * @return number of tasks pending right now
254 GNUNET_SCHEDULER_get_load (enum GNUNET_SCHEDULER_Priority p);
258 * Obtain the reason code for why the current task was
259 * started. Will return the same value as
260 * the GNUNET_SCHEDULER_TaskContext's reason field.
262 * * @return reason(s) why the current task is run
264 enum GNUNET_SCHEDULER_Reason
265 GNUNET_SCHEDULER_get_reason ();
269 * Cancel the task with the specified identifier.
270 * The task must not yet have run.
272 * * @param task id of the task to cancel
273 * @return the closure of the callback of the cancelled task
276 GNUNET_SCHEDULER_cancel (GNUNET_SCHEDULER_TaskIdentifier task);
280 * Continue the current execution with the given function. This is
281 * similar to the other "add" functions except that there is no delay
282 * and the reason code can be specified.
284 * * @param task main function of the task
285 * @param task_cls closure of task
286 * @param reason reason for task invocation
289 GNUNET_SCHEDULER_add_continuation (GNUNET_SCHEDULER_Task task, void *task_cls,
290 enum GNUNET_SCHEDULER_Reason reason);
294 * Schedule a new task to be run after the specified prerequisite task
295 * has completed. It will be run with the priority of the calling
298 * * @param prerequisite_task run this task after the task with the given
299 * task identifier completes (and any of our other
300 * conditions, such as delay, read or write-readiness
301 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
302 * on completion of other tasks (this will cause the task to run as
304 * @param task main function of the task
305 * @param task_cls closure of task
306 * @return unique task identifier for the job
307 * only valid until "task" is started!
309 GNUNET_SCHEDULER_TaskIdentifier
310 GNUNET_SCHEDULER_add_after (GNUNET_SCHEDULER_TaskIdentifier prerequisite_task,
311 GNUNET_SCHEDULER_Task task, void *task_cls);
315 * Schedule a new task to be run with a specified priority.
317 * * @param prio how important is the new task?
318 * @param task main function of the task
319 * @param task_cls closure of task
320 * @return unique task identifier for the job
321 * only valid until "task" is started!
323 GNUNET_SCHEDULER_TaskIdentifier
324 GNUNET_SCHEDULER_add_with_priority (enum GNUNET_SCHEDULER_Priority prio,
325 GNUNET_SCHEDULER_Task task, void *task_cls);
329 * Schedule a new task to be run as soon as possible. The task
330 * will be run with the priority of the calling task.
332 * * @param task main function of the task
333 * @param task_cls closure of task
334 * @return unique task identifier for the job
335 * only valid until "task" is started!
337 GNUNET_SCHEDULER_TaskIdentifier
338 GNUNET_SCHEDULER_add_now (GNUNET_SCHEDULER_Task task, void *task_cls);
342 * Schedule a new task to be run as soon as possible with the
343 * (transitive) ignore-shutdown flag either explicitly set or
344 * explicitly enabled. This task (and all tasks created from it,
345 * other than by another call to this function) will either count or
346 * not count for the 'lifeness' of the process. This API is only
347 * useful in a few special cases.
349 * @param lifeness GNUNET_YES if the task counts for lifeness, GNUNET_NO if not.
350 * @param task main function of the task
351 * @param task_cls closure of task
352 * @return unique task identifier for the job
353 * only valid until "task" is started!
355 GNUNET_SCHEDULER_TaskIdentifier
356 GNUNET_SCHEDULER_add_now_with_lifeness (int lifeness,
357 GNUNET_SCHEDULER_Task task,
362 * Schedule a new task to be run with a specified delay. The task
363 * will be scheduled for execution once the delay has expired. It
364 * will be run with the priority of the calling task.
366 * * @param delay when should this operation time out? Use
367 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
368 * @param task main function of the task
369 * @param task_cls closure of task
370 * @return unique task identifier for the job
371 * only valid until "task" is started!
373 GNUNET_SCHEDULER_TaskIdentifier
374 GNUNET_SCHEDULER_add_delayed (struct GNUNET_TIME_Relative delay,
375 GNUNET_SCHEDULER_Task task, void *task_cls);
379 * Schedule a new task to be run with a specified delay or when the
380 * specified file descriptor is ready for reading. The delay can be
381 * used as a timeout on the socket being ready. The task will be
382 * scheduled for execution once either the delay has expired or the
383 * socket operation is ready. It will be run with the priority of
386 * * @param delay when should this operation time out? Use
387 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
388 * @param rfd read file-descriptor
389 * @param task main function of the task
390 * @param task_cls closure of task
391 * @return unique task identifier for the job
392 * only valid until "task" is started!
394 GNUNET_SCHEDULER_TaskIdentifier
395 GNUNET_SCHEDULER_add_read_net (struct GNUNET_TIME_Relative delay,
396 struct GNUNET_NETWORK_Handle *rfd,
397 GNUNET_SCHEDULER_Task task, void *task_cls);
401 * Schedule a new task to be run with a specified delay or when the
402 * specified file descriptor is ready for writing. The delay can be
403 * used as a timeout on the socket being ready. The task will be
404 * scheduled for execution once either the delay has expired or the
405 * socket operation is ready. It will be run with the priority of
408 * * @param delay when should this operation time out? Use
409 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
410 * @param wfd write file-descriptor
411 * @param task main function of the task
412 * @param task_cls closure of task
413 * @return unique task identifier for the job
414 * only valid until "task" is started!
416 GNUNET_SCHEDULER_TaskIdentifier
417 GNUNET_SCHEDULER_add_write_net (struct GNUNET_TIME_Relative delay,
418 struct GNUNET_NETWORK_Handle *wfd,
419 GNUNET_SCHEDULER_Task task, void *task_cls);
423 * Schedule a new task to be run with a specified delay or when the
424 * specified file descriptor is ready for reading. The delay can be
425 * used as a timeout on the socket being ready. The task will be
426 * scheduled for execution once either the delay has expired or the
427 * socket operation is ready. It will be run with the priority of
430 * * @param delay when should this operation time out? Use
431 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
432 * @param rfd read file-descriptor
433 * @param task main function of the task
434 * @param task_cls closure of task
435 * @return unique task identifier for the job
436 * only valid until "task" is started!
438 GNUNET_SCHEDULER_TaskIdentifier
439 GNUNET_SCHEDULER_add_read_file (struct GNUNET_TIME_Relative delay,
440 const struct GNUNET_DISK_FileHandle *rfd,
441 GNUNET_SCHEDULER_Task task, void *task_cls);
445 * Schedule a new task to be run with a specified delay or when the
446 * specified file descriptor is ready for writing. The delay can be
447 * used as a timeout on the socket being ready. The task will be
448 * scheduled for execution once either the delay has expired or the
449 * socket operation is ready. It will be run with the priority of
452 * * @param delay when should this operation time out? Use
453 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
454 * @param wfd write file-descriptor
455 * @param task main function of the task
456 * @param task_cls closure of task
457 * @return unique task identifier for the job
458 * only valid until "task" is started!
460 GNUNET_SCHEDULER_TaskIdentifier
461 GNUNET_SCHEDULER_add_write_file (struct GNUNET_TIME_Relative delay,
462 const struct GNUNET_DISK_FileHandle *wfd,
463 GNUNET_SCHEDULER_Task task, void *task_cls);
467 * Schedule a new task to be run with a specified delay or when any of
468 * the specified file descriptor sets is ready. The delay can be used
469 * as a timeout on the socket(s) being ready. The task will be
470 * scheduled for execution once either the delay has expired or any of
471 * the socket operations is ready. This is the most general
472 * function of the "add" family. Note that the "prerequisite_task"
473 * must be satisfied in addition to any of the other conditions. In
474 * other words, the task will be started when
480 * || shutdown-active)
483 * * @param prio how important is this task?
484 * @param prerequisite_task run this task after the task with the given
485 * task identifier completes (and any of our other
486 * conditions, such as delay, read or write-readiness
487 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
488 * on completion of other tasks.
489 * @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
490 * which means that the task will only be run after we receive SIGTERM
491 * @param rs set of file descriptors we want to read (can be NULL)
492 * @param ws set of file descriptors we want to write (can be NULL)
493 * @param task main function of the task
494 * @param task_cls closure of task
495 * @return unique task identifier for the job
496 * only valid until "task" is started!
498 GNUNET_SCHEDULER_TaskIdentifier
499 GNUNET_SCHEDULER_add_select (enum GNUNET_SCHEDULER_Priority prio,
500 GNUNET_SCHEDULER_TaskIdentifier prerequisite_task,
501 struct GNUNET_TIME_Relative delay,
502 const struct GNUNET_NETWORK_FDSet *rs,
503 const struct GNUNET_NETWORK_FDSet *ws,
504 GNUNET_SCHEDULER_Task task, void *task_cls);
507 * Sets the select function to use in the scheduler (scheduler_select).
509 * @param new_select new select function to use (NULL to reset to default)
510 * @param new_select_cls closure for 'new_select'
513 GNUNET_SCHEDULER_set_select (GNUNET_SCHEDULER_select new_select,
514 void *new_select_cls);
517 #if 0 /* keep Emacsens' auto-indent happy */