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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). Any task that is scheduled
115 * without an explicit priority being specified
116 * will run with this priority.
118 GNUNET_SCHEDULER_PRIORITY_DEFAULT = 3,
121 * Run with high priority (important requests).
122 * Higher than DEFAULT.
124 GNUNET_SCHEDULER_PRIORITY_HIGH = 4,
127 * Run with priority for interactive tasks.
128 * Higher than "HIGH".
130 GNUNET_SCHEDULER_PRIORITY_UI = 5,
133 * Run with priority for urgent tasks. Use
134 * for things like aborts and shutdowns that
135 * need to preempt "UI"-level tasks.
138 GNUNET_SCHEDULER_PRIORITY_URGENT = 6,
141 * This is an internal priority level that is only used for tasks
142 * that are being triggered due to shutdown (they have automatically
143 * highest priority). User code must not use this priority level
144 * directly. Tasks run with this priority level that internally
145 * schedule other tasks will see their original priority level
146 * be inherited (unless otherwise specified).
148 GNUNET_SCHEDULER_PRIORITY_SHUTDOWN = 7,
151 * Number of priorities (must be the last priority).
152 * This priority must not be used by clients.
154 GNUNET_SCHEDULER_PRIORITY_COUNT = 8
157 #include "gnunet_time_lib.h"
158 #include "gnunet_network_lib.h"
162 * Context information passed to each scheduler task.
164 struct GNUNET_SCHEDULER_TaskContext
167 * Reason why the task is run now
169 enum GNUNET_SCHEDULER_Reason reason;
172 * Set of file descriptors ready for reading;
173 * note that additional bits may be set
174 * that were not in the original request
176 const struct GNUNET_NETWORK_FDSet *read_ready;
179 * Set of file descriptors ready for writing;
180 * note that additional bits may be set
181 * that were not in the original request.
183 const struct GNUNET_NETWORK_FDSet *write_ready;
189 * Signature of the main function of a task.
192 * @param tc context information (why was this task triggered now)
194 typedef void (*GNUNET_SCHEDULER_Task) (void *cls,
195 const struct GNUNET_SCHEDULER_TaskContext
200 * Signature of the select function used by the scheduler.
201 * GNUNET_NETWORK_socket_select matches it.
204 * @param rfds set of sockets to be checked for readability
205 * @param wfds set of sockets to be checked for writability
206 * @param efds set of sockets to be checked for exceptions
207 * @param timeout relative value when to return
208 * @return number of selected sockets, GNUNET_SYSERR on error
210 typedef int (*GNUNET_SCHEDULER_select) (void *cls,
211 struct GNUNET_NETWORK_FDSet * rfds,
212 struct GNUNET_NETWORK_FDSet * wfds,
213 struct GNUNET_NETWORK_FDSet * efds,
214 struct GNUNET_TIME_Relative timeout);
216 * Initialize and run scheduler. This function will return when all
217 * tasks have completed. On systems with signals, receiving a SIGTERM
218 * (and other similar signals) will cause "GNUNET_SCHEDULER_shutdown"
219 * to be run after the active task is complete. As a result, SIGTERM
220 * causes all active tasks to be scheduled with reason
221 * "GNUNET_SCHEDULER_REASON_SHUTDOWN". (However, tasks added
222 * afterwards will execute normally!). Note that any particular
223 * signal will only shut down one scheduler; applications should
224 * always only create a single scheduler.
226 * @param task task to run first (and immediately)
227 * @param task_cls closure of task
230 GNUNET_SCHEDULER_run (GNUNET_SCHEDULER_Task task, void *task_cls);
234 * Request the shutdown of a scheduler. Marks all currently
235 * pending tasks as ready because of shutdown. This will
236 * cause all tasks to run (as soon as possible, respecting
237 * priorities and prerequisite tasks). Note that tasks
238 * scheduled AFTER this call may still be delayed arbitrarily.
241 GNUNET_SCHEDULER_shutdown ();
245 * Get information about the current load of this scheduler. Use this
246 * function to determine if an elective task should be added or simply
247 * dropped (if the decision should be made based on the number of
248 * tasks ready to run).
250 * * @param p priority-level to query, use KEEP to query the level
251 * of the current task, use COUNT to get the sum over
252 * all priority levels
253 * @return number of tasks pending right now
256 GNUNET_SCHEDULER_get_load (enum GNUNET_SCHEDULER_Priority p);
260 * Obtain the reason code for why the current task was
261 * started. Will return the same value as
262 * the GNUNET_SCHEDULER_TaskContext's reason field.
264 * * @return reason(s) why the current task is run
266 enum GNUNET_SCHEDULER_Reason
267 GNUNET_SCHEDULER_get_reason (void);
271 * Cancel the task with the specified identifier.
272 * The task must not yet have run.
274 * * @param task id of the task to cancel
275 * @return the closure of the callback of the cancelled task
278 GNUNET_SCHEDULER_cancel (GNUNET_SCHEDULER_TaskIdentifier task);
282 * Continue the current execution with the given function. This is
283 * similar to the other "add" functions except that there is no delay
284 * and the reason code can be specified.
286 * * @param task main function of the task
287 * @param task_cls closure of task
288 * @param reason reason for task invocation
291 GNUNET_SCHEDULER_add_continuation (GNUNET_SCHEDULER_Task task, void *task_cls,
292 enum GNUNET_SCHEDULER_Reason reason);
296 * Continue the current execution with the given function. This is
297 * similar to the other "add" functions except that there is no delay
298 * and the reason code can be specified.
300 * @param task main function of the task
301 * @param task_cls closure for 'main'
302 * @param reason reason for task invocation
303 * @param priority priority to use for the task
306 GNUNET_SCHEDULER_add_continuation_with_priority (GNUNET_SCHEDULER_Task task, void *task_cls,
307 enum GNUNET_SCHEDULER_Reason reason,
308 enum GNUNET_SCHEDULER_Priority priority);
312 * Schedule a new task to be run with a specified priority.
314 * * @param prio how important is the new task?
315 * @param task main function of the task
316 * @param task_cls closure of task
317 * @return unique task identifier for the job
318 * only valid until "task" is started!
320 GNUNET_SCHEDULER_TaskIdentifier
321 GNUNET_SCHEDULER_add_with_priority (enum GNUNET_SCHEDULER_Priority prio,
322 GNUNET_SCHEDULER_Task task, void *task_cls);
326 * Schedule a new task to be run as soon as possible. The task
327 * will be run with the DEFAULT priority.
329 * * @param task main function of the task
330 * @param task_cls closure of task
331 * @return unique task identifier for the job
332 * only valid until "task" is started!
334 GNUNET_SCHEDULER_TaskIdentifier
335 GNUNET_SCHEDULER_add_now (GNUNET_SCHEDULER_Task task, void *task_cls);
339 * Schedule a new task to be run as soon as possible with the
340 * (transitive) ignore-shutdown flag either explicitly set or
341 * explicitly enabled. This task (and all tasks created from it,
342 * other than by another call to this function) will either count or
343 * not count for the 'lifeness' of the process. This API is only
344 * useful in a few special cases.
346 * @param lifeness GNUNET_YES if the task counts for lifeness, GNUNET_NO if not.
347 * @param task main function of the task
348 * @param task_cls closure of task
349 * @return unique task identifier for the job
350 * only valid until "task" is started!
352 GNUNET_SCHEDULER_TaskIdentifier
353 GNUNET_SCHEDULER_add_now_with_lifeness (int lifeness,
354 GNUNET_SCHEDULER_Task task,
359 * Schedule a new task to be run with a specified delay. The task
360 * will be scheduled for execution once the delay has expired. It
361 * will be run with the DEFAULT priority.
363 * * @param delay when should this operation time out? Use
364 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
365 * @param task main function of the task
366 * @param task_cls closure of task
367 * @return unique task identifier for the job
368 * only valid until "task" is started!
370 GNUNET_SCHEDULER_TaskIdentifier
371 GNUNET_SCHEDULER_add_delayed (struct GNUNET_TIME_Relative delay,
372 GNUNET_SCHEDULER_Task task, void *task_cls);
376 * Schedule a new task to be run with a specified delay. The task
377 * will be scheduled for execution once the delay has expired.
379 * @param delay when should this operation time out? Use
380 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
381 * @param priority priority to use for the task
382 * @param task main function of the task
383 * @param task_cls closure of task
384 * @return unique task identifier for the job
385 * only valid until "task" is started!
387 GNUNET_SCHEDULER_TaskIdentifier
388 GNUNET_SCHEDULER_add_delayed_with_priority (struct GNUNET_TIME_Relative delay,
389 enum GNUNET_SCHEDULER_Priority priority,
390 GNUNET_SCHEDULER_Task task, void *task_cls);
394 * Schedule a new task to be run with a specified delay or when the
395 * specified file descriptor is ready for reading. The delay can be
396 * used as a timeout on the socket being ready. The task will be
397 * scheduled for execution once either the delay has expired or the
398 * socket operation is ready. It will be run with the DEFAULT priority.
400 * * @param delay when should this operation time out? Use
401 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
402 * @param rfd read file-descriptor
403 * @param task main function of the task
404 * @param task_cls closure of task
405 * @return unique task identifier for the job
406 * only valid until "task" is started!
408 GNUNET_SCHEDULER_TaskIdentifier
409 GNUNET_SCHEDULER_add_read_net (struct GNUNET_TIME_Relative delay,
410 struct GNUNET_NETWORK_Handle *rfd,
411 GNUNET_SCHEDULER_Task task, void *task_cls);
415 * Schedule a new task to be run with a specified delay or when the
416 * specified file descriptor is ready for writing. The delay can be
417 * used as a timeout on the socket being ready. The task will be
418 * scheduled for execution once either the delay has expired or the
419 * socket operation is ready. It will be run with the DEFAULT priority.
421 * * @param delay when should this operation time out? Use
422 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
423 * @param wfd write file-descriptor
424 * @param task main function of the task
425 * @param task_cls closure of task
426 * @return unique task identifier for the job
427 * only valid until "task" is started!
429 GNUNET_SCHEDULER_TaskIdentifier
430 GNUNET_SCHEDULER_add_write_net (struct GNUNET_TIME_Relative delay,
431 struct GNUNET_NETWORK_Handle *wfd,
432 GNUNET_SCHEDULER_Task task, void *task_cls);
436 * Schedule a new task to be run with a specified delay or when the
437 * specified file descriptor is ready for reading. The delay can be
438 * used as a timeout on the socket being ready. The task will be
439 * scheduled for execution once either the delay has expired or the
440 * socket operation is ready. It will be run with the DEFAULT priority.
442 * * @param delay when should this operation time out? Use
443 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
444 * @param rfd read file-descriptor
445 * @param task main function of the task
446 * @param task_cls closure of task
447 * @return unique task identifier for the job
448 * only valid until "task" is started!
450 GNUNET_SCHEDULER_TaskIdentifier
451 GNUNET_SCHEDULER_add_read_file (struct GNUNET_TIME_Relative delay,
452 const struct GNUNET_DISK_FileHandle *rfd,
453 GNUNET_SCHEDULER_Task task, void *task_cls);
457 * Schedule a new task to be run with a specified delay or when the
458 * specified file descriptor is ready for writing. The delay can be
459 * used as a timeout on the socket being ready. The task will be
460 * scheduled for execution once either the delay has expired or the
461 * socket operation is ready. It will be run with the DEFAULT priority.
463 * * @param delay when should this operation time out? Use
464 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
465 * @param wfd write file-descriptor
466 * @param task main function of the task
467 * @param task_cls closure of task
468 * @return unique task identifier for the job
469 * only valid until "task" is started!
471 GNUNET_SCHEDULER_TaskIdentifier
472 GNUNET_SCHEDULER_add_write_file (struct GNUNET_TIME_Relative delay,
473 const struct GNUNET_DISK_FileHandle *wfd,
474 GNUNET_SCHEDULER_Task task, void *task_cls);
478 * Schedule a new task to be run with a specified delay or when any of
479 * the specified file descriptor sets is ready. The delay can be used
480 * as a timeout on the socket(s) being ready. The task will be
481 * scheduled for execution once either the delay has expired or any of
482 * the socket operations is ready. This is the most general
483 * function of the "add" family. Note that the "prerequisite_task"
484 * must be satisfied in addition to any of the other conditions. In
485 * other words, the task will be started when
491 * || shutdown-active)
494 * @param prio how important is this task?
495 * @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
496 * which means that the task will only be run after we receive SIGTERM
497 * @param rs set of file descriptors we want to read (can be NULL)
498 * @param ws set of file descriptors we want to write (can be NULL)
499 * @param task main function of the task
500 * @param task_cls closure of task
501 * @return unique task identifier for the job
502 * only valid until "task" is started!
504 GNUNET_SCHEDULER_TaskIdentifier
505 GNUNET_SCHEDULER_add_select (enum GNUNET_SCHEDULER_Priority prio,
506 struct GNUNET_TIME_Relative delay,
507 const struct GNUNET_NETWORK_FDSet *rs,
508 const struct GNUNET_NETWORK_FDSet *ws,
509 GNUNET_SCHEDULER_Task task, void *task_cls);
512 * Sets the select function to use in the scheduler (scheduler_select).
514 * @param new_select new select function to use (NULL to reset to default)
515 * @param new_select_cls closure for 'new_select'
518 GNUNET_SCHEDULER_set_select (GNUNET_SCHEDULER_select new_select,
519 void *new_select_cls);
522 #if 0 /* keep Emacsens' auto-indent happy */