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3 (C) 2009 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 */
40 * Opaque handle for the scheduling service.
42 struct GNUNET_SCHEDULER_Handle;
45 * Opaque reference to a task.
47 typedef unsigned long long GNUNET_SCHEDULER_TaskIdentifier;
51 * Constant used to indicate that the scheduled
52 * task has no others as prerequisites.
54 #define GNUNET_SCHEDULER_NO_TASK ((GNUNET_SCHEDULER_TaskIdentifier) 0)
57 * Reasons why the schedule may have triggered
60 enum GNUNET_SCHEDULER_Reason
63 * This is the very first task run during startup.
65 GNUNET_SCHEDULER_REASON_STARTUP = 0,
68 * We are shutting down and are running all shutdown-related tasks
69 * (regardless of timeout, etc.).
71 GNUNET_SCHEDULER_REASON_SHUTDOWN = 1,
74 * The specified timeout has expired.
75 * (also set if the delay given was 0).
77 GNUNET_SCHEDULER_REASON_TIMEOUT = 2,
80 * The reading socket is ready.
82 GNUNET_SCHEDULER_REASON_READ_READY = 4,
85 * The writing socket is ready.
87 GNUNET_SCHEDULER_REASON_WRITE_READY = 8,
90 * The prerequisite task is done.
92 GNUNET_SCHEDULER_REASON_PREREQ_DONE = 16
97 * Valid task priorities. Use these, do not
98 * pass random integers!
100 enum GNUNET_SCHEDULER_Priority
103 * Run with the same priority as the current job.
105 GNUNET_SCHEDULER_PRIORITY_KEEP = 0,
108 * Run when otherwise idle.
110 GNUNET_SCHEDULER_PRIORITY_IDLE = 1,
113 * Run as background job (higher than idle,
114 * lower than default).
116 GNUNET_SCHEDULER_PRIORITY_BACKGROUND = 2,
119 * Run with the default priority (normal
120 * P2P operations). Higher than BACKGROUND.
122 GNUNET_SCHEDULER_PRIORITY_DEFAULT = 3,
125 * Run with high priority (important requests).
126 * Higher than DEFAULT.
128 GNUNET_SCHEDULER_PRIORITY_HIGH = 4,
131 * Run with priority for interactive tasks.
132 * Higher than "HIGH".
134 GNUNET_SCHEDULER_PRIORITY_UI = 5,
137 * Run with priority for urgent tasks. Use
138 * for things like aborts and shutdowns that
139 * need to preempt "UI"-level tasks.
142 GNUNET_SCHEDULER_PRIORITY_URGENT = 6,
145 * Number of priorities (must be the last priority).
146 * This priority must not be used by clients.
148 GNUNET_SCHEDULER_PRIORITY_COUNT = 7
151 #include "gnunet_time_lib.h"
152 #include "gnunet_network_lib.h"
156 * Context information passed to each scheduler task.
158 struct GNUNET_SCHEDULER_TaskContext
162 * Scheduler running the task
164 struct GNUNET_SCHEDULER_Handle *sched;
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,
196 GNUNET_SCHEDULER_TaskContext * tc);
200 * Initialize and run scheduler. This function will return when all
201 * tasks have completed. On systems with signals, receiving a SIGTERM
202 * (and other similar signals) will cause "GNUNET_SCHEDULER_shutdown"
203 * to be run after the active task is complete. As a result, SIGTERM
204 * causes all active tasks to be scheduled with reason
205 * "GNUNET_SCHEDULER_REASON_SHUTDOWN". (However, tasks added
206 * afterwards will execute normally!). Note that any particular
207 * signal will only shut down one scheduler; applications should
208 * always only create a single scheduler.
210 * @param task task to run first (and immediately)
211 * @param task_cls closure of task
213 void GNUNET_SCHEDULER_run (GNUNET_SCHEDULER_Task task, void *task_cls);
217 * Request the shutdown of a scheduler. Marks all currently
218 * pending tasks as ready because of shutdown. This will
219 * cause all tasks to run (as soon as possible, respecting
220 * priorities and prerequisite tasks). Note that tasks
221 * scheduled AFTER this call may still be delayed arbitrarily.
223 * @param sched the scheduler
225 void GNUNET_SCHEDULER_shutdown (struct GNUNET_SCHEDULER_Handle *sched);
229 * Get information about the current load of this scheduler. Use this
230 * function to determine if an elective task should be added or simply
231 * dropped (if the decision should be made based on the number of
232 * tasks ready to run).
234 * @param sched scheduler to query
235 * @param p priority-level to query, use KEEP to query the level
236 * of the current task, use COUNT to get the sum over
237 * all priority levels
238 * @return number of tasks pending right now
240 unsigned int GNUNET_SCHEDULER_get_load (struct GNUNET_SCHEDULER_Handle *sched,
241 enum GNUNET_SCHEDULER_Priority p);
245 * Obtain the reason code for why the current task was
246 * started. Will return the same value as
247 * the GNUNET_SCHEDULER_TaskContext's reason field.
249 * @param sched scheduler to query
250 * @return reason(s) why the current task is run
252 enum GNUNET_SCHEDULER_Reason
253 GNUNET_SCHEDULER_get_reason (struct GNUNET_SCHEDULER_Handle *sched);
257 * Cancel the task with the specified identifier.
258 * The task must not yet have run.
260 * @param sched scheduler to use
261 * @param task id of the task to cancel
262 * @return the closure of the callback of the cancelled task
264 void *GNUNET_SCHEDULER_cancel (struct GNUNET_SCHEDULER_Handle *sched,
265 GNUNET_SCHEDULER_TaskIdentifier task);
269 * Continue the current execution with the given function. This is
270 * similar to the other "add" functions except that there is no delay
271 * and the reason code can be specified.
273 * @param sched scheduler to use
274 * @param main main function of the task
275 * @param cls closure of task
276 * @param reason reason for task invocation
279 GNUNET_SCHEDULER_add_continuation (struct GNUNET_SCHEDULER_Handle *sched,
280 GNUNET_SCHEDULER_Task main,
282 enum GNUNET_SCHEDULER_Reason reason);
286 * Schedule a new task to be run after the specified prerequisite task
287 * has completed. It will be run with the priority of the calling
290 * @param sched scheduler to use
291 * @param prerequisite_task run this task after the task with the given
292 * task identifier completes (and any of our other
293 * conditions, such as delay, read or write-readyness
294 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
295 * on completion of other tasks (this will cause the task to run as
297 * @param task main function of the task
298 * @param task_cls closure of task
299 * @return unique task identifier for the job
300 * only valid until "task" is started!
302 GNUNET_SCHEDULER_TaskIdentifier
303 GNUNET_SCHEDULER_add_after (struct GNUNET_SCHEDULER_Handle *sched,
304 GNUNET_SCHEDULER_TaskIdentifier prerequisite_task,
305 GNUNET_SCHEDULER_Task task,
310 * Schedule a new task to be run with a specified priority.
312 * @param sched scheduler to use
313 * @param prio how important is the new task?
314 * @param task main function of the task
315 * @param task_cls closure of task
316 * @return unique task identifier for the job
317 * only valid until "task" is started!
319 GNUNET_SCHEDULER_TaskIdentifier
320 GNUNET_SCHEDULER_add_with_priority (struct GNUNET_SCHEDULER_Handle *sched,
321 enum GNUNET_SCHEDULER_Priority prio,
322 GNUNET_SCHEDULER_Task task,
327 * Schedule a new task to be run with a specified delay. The task
328 * will be scheduled for execution once the delay has expired. It
329 * will be run with the priority of the calling task.
331 * @param sched scheduler to use
332 * @param delay when should this operation time out? Use
333 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
334 * @param task main function of the task
335 * @param task_cls closure of task
336 * @return unique task identifier for the job
337 * only valid until "task" is started!
339 GNUNET_SCHEDULER_TaskIdentifier
340 GNUNET_SCHEDULER_add_delayed (struct GNUNET_SCHEDULER_Handle *sched,
341 struct GNUNET_TIME_Relative delay,
342 GNUNET_SCHEDULER_Task task,
347 * Schedule a new task to be run with a specified delay or when the
348 * specified file descriptor is ready for reading. The delay can be
349 * used as a timeout on the socket being ready. The task will be
350 * scheduled for execution once either the delay has expired or the
351 * socket operation is ready. It will be run with the priority of
354 * @param sched scheduler to use
355 * @param delay when should this operation time out? Use
356 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
357 * @param rfd read file-descriptor
358 * @param task main function of the task
359 * @param task_cls closure of task
360 * @return unique task identifier for the job
361 * only valid until "task" is started!
363 GNUNET_SCHEDULER_TaskIdentifier
364 GNUNET_SCHEDULER_add_read_net (struct GNUNET_SCHEDULER_Handle *sched,
365 struct GNUNET_TIME_Relative delay,
366 struct GNUNET_NETWORK_Handle *rfd,
367 GNUNET_SCHEDULER_Task task,
372 * Schedule a new task to be run with a specified delay or when the
373 * specified file descriptor is ready for writing. The delay can be
374 * used as a timeout on the socket being ready. The task will be
375 * scheduled for execution once either the delay has expired or the
376 * socket operation is ready. It will be run with the priority of
379 * @param sched scheduler to use
380 * @param delay when should this operation time out? Use
381 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
382 * @param wfd write file-descriptor
383 * @param task main function of the task
384 * @param task_cls closure of task
385 * @return unique task identifier for the job
386 * only valid until "task" is started!
388 GNUNET_SCHEDULER_TaskIdentifier
389 GNUNET_SCHEDULER_add_write_net (struct GNUNET_SCHEDULER_Handle *sched,
390 struct GNUNET_TIME_Relative delay,
391 struct GNUNET_NETWORK_Handle *wfd,
392 GNUNET_SCHEDULER_Task task,
397 * Schedule a new task to be run with a specified delay or when the
398 * specified file descriptor is ready for reading. The delay can be
399 * used as a timeout on the socket being ready. The task will be
400 * scheduled for execution once either the delay has expired or the
401 * socket operation is ready. It will be run with the priority of
404 * @param sched scheduler to use
405 * @param delay when should this operation time out? Use
406 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
407 * @param rfd read file-descriptor
408 * @param task main function of the task
409 * @param task_cls closure of task
410 * @return unique task identifier for the job
411 * only valid until "task" is started!
413 GNUNET_SCHEDULER_TaskIdentifier
414 GNUNET_SCHEDULER_add_read_file (struct GNUNET_SCHEDULER_Handle *sched,
415 struct GNUNET_TIME_Relative delay,
416 const struct GNUNET_DISK_FileHandle *rfd,
417 GNUNET_SCHEDULER_Task task,
422 * Schedule a new task to be run with a specified delay or when the
423 * specified file descriptor is ready for writing. The delay can be
424 * used as a timeout on the socket being ready. The task will be
425 * scheduled for execution once either the delay has expired or the
426 * socket operation is ready. It will be run with the priority of
429 * @param sched scheduler to use
430 * @param delay when should this operation time out? Use
431 * GNUNET_TIME_UNIT_FOREVER_REL for "on shutdown"
432 * @param wfd write 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_write_file (struct GNUNET_SCHEDULER_Handle *sched,
440 struct GNUNET_TIME_Relative delay,
441 const struct GNUNET_DISK_FileHandle *wfd,
442 GNUNET_SCHEDULER_Task task,
447 * Schedule a new task to be run with a specified delay or when any of
448 * the specified file descriptor sets is ready. The delay can be used
449 * as a timeout on the socket(s) being ready. The task will be
450 * scheduled for execution once either the delay has expired or any of
451 * the socket operations is ready. This is the most general
452 * function of the "add" family. Note that the "prerequisite_task"
453 * must be satisfied in addition to any of the other conditions. In
454 * other words, the task will be started when
460 * || (shutdown-active && run-on-shutdown) )
463 * @param sched scheduler to use
464 * @param prio how important is this task?
465 * @param prerequisite_task run this task after the task with the given
466 * task identifier completes (and any of our other
467 * conditions, such as delay, read or write-readyness
468 * are satisfied). Use GNUNET_SCHEDULER_NO_TASK to not have any dependency
469 * on completion of other tasks.
470 * @param delay how long should we wait? Use GNUNET_TIME_UNIT_FOREVER_REL for "forever",
471 * which means that the task will only be run after we receive SIGTERM
472 * @param rs set of file descriptors we want to read (can be NULL)
473 * @param ws set of file descriptors we want to write (can be NULL)
474 * @param task main function of the task
475 * @param task_cls closure of task
476 * @return unique task identifier for the job
477 * only valid until "task" is started!
479 GNUNET_SCHEDULER_TaskIdentifier
480 GNUNET_SCHEDULER_add_select (struct GNUNET_SCHEDULER_Handle *sched,
481 enum GNUNET_SCHEDULER_Priority prio,
482 GNUNET_SCHEDULER_TaskIdentifier
484 struct GNUNET_TIME_Relative delay,
485 const struct GNUNET_NETWORK_FDSet * rs,
486 const struct GNUNET_NETWORK_FDSet * ws,
487 GNUNET_SCHEDULER_Task task,
490 #if 0 /* keep Emacsens' auto-indent happy */