X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.h;h=35e2503e383be3611fc302f5a732e45cf322d506;hp=d7b90a45b7b2e10947a03ed610c649181f448b0a;hb=HEAD;hpb=bc15c3ff65eb00e04ebc303cfa9ee3d1a4675b35

diff --git a/sched.h b/sched.h
index d7b90a45..ede5e67e 100644
--- a/sched.h
+++ b/sched.h
@@ -1,8 +1,4 @@
-/*
- * Copyright (C) 2006-2014 Andre Noll <maan@tuebingen.mpg.de>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
 
 /** \file sched.h Sched and task structures and exported symbols from sched.c. */
 
@@ -11,24 +7,30 @@
  * Paraslash's scheduler.
  *
  * Designed with KISS in mind. It maintains a list of task structures which is
- * extended when a new task is registered. Each task may define a pre_select
+ * extended when a new task is registered. Each task may define a pre_monitor
  * function which is called from the scheduler main loop before it calls
- * select(). Similarly, each task must define a post_select function which is
- * called after the select call.
+ * poll(2). Similarly, each task must define a post_monitor function which is
+ * called after poll(2) returns.
+ *
+ * \sa select(2), poll(2).
  */
 struct sched {
-	/** Initial value before any pre_select call. */
-	struct timeval default_timeout;
-	/** The current timeout for the upcoming select call. */
-	struct timeval select_timeout;
-	/** fds that should be watched for readability. */
-	fd_set rfds;
-	/** fds that should be watched for writability. */
-	fd_set wfds;
-	/** Highest numbered file descriptor in any of the above fd sets. */
-	int max_fileno;
-	/** If non-NULL, use this function instead of para_select. */
-	int (*select_function)(int, fd_set *, fd_set *, struct timeval *);
+	/** Initial value (in milliseconds) before any pre_monitor call. */
+	int default_timeout;
+	/** The timeout (also in milliseconds) for the next iteration. */
+	int timeout;
+	/** Passed to poll(2). */
+	struct pollfd *pfd;
+	/** Number of elements in the above array, passed to poll(2). */
+	unsigned pfd_array_len;
+	/** Number of fds registered for montitoring so far. */
+	unsigned num_pfds;
+	/** Maps fds to indices of the pfd array. */
+	unsigned *pidx;
+	/** Mumber of elements in the above pidx array. */
+	unsigned pidx_array_len;
+	/** If non-NULL, use this function instead of \ref xpoll(). */
+	int (*poll_function)(struct pollfd *fds, nfds_t nfds, int timeout);
 	/** Tasks which have been registered to the scheduler. */
 	struct list_head task_list;
 };
@@ -40,23 +42,32 @@ struct task_info {
 	/** Used for log messages and by \ref get_task_list(). */
 	const char *name;
 	/**
-	 * The optional pre select method.
+	 * Configure watch fds and impose an upper bound on the I/O timeout.
 	 *
-	 * Its purpose is to add file descriptors to the fd sets of the
-	 * scheduler and to decrease the select timeout if necessary.
+	 * If this is not NULL, the function is called at each iteration of the
+	 * scheduler's main loop. Its purpose is to tell the scheduler that
+	 * certain file descriptors should be monitored for readiness for I/O.
+	 * The function may also lower the scheduler's timeout value (but shall
+	 * never increase it) to impose an upper bound on the waiting time in
+	 * case no file descriptors happen to be ready.
+	 *
+	 * \sa \ref time.c.
 	 */
-	void (*pre_select)(struct sched *s, void *context);
+	void (*pre_monitor)(struct sched *s, void *context);
 	/**
-	 * The mandatory post select method.
+	 * Perform I/O on file descriptors which are ready for I/O.
+	 *
+	 * This mandatory hook is called after the system call which monitors
+	 * file descriptors returns. The function should perform non-blocking
+	 * I/O on those file descriptors which are reported as being ready.
 	 *
-	 * Its purpose is to evaluate and act upon the results of the previous
-	 * select call. If this function returns a negative value, the
-	 * scheduler unregisters the task.
+	 * If this function returns a negative value, the scheduler unregisters
+	 * the task.
 	 */
-	int (*post_select)(struct sched *s, void *context);
+	int (*post_monitor)(struct sched *s, void *context);
 	/**
 	 * This pointer is saved when the task is registered. It is passed to
-	 * ->pre_select() and ->post_select(). Usually this is a pointer to the
+	 * ->pre_monitor() and ->post_monitor(). Usually this is a pointer to the
 	 * struct owned by the caller which contains the task pointer.
 	 */
 	void *context;
@@ -84,3 +95,7 @@ void sched_request_timeout(struct timeval *to, struct sched *s);
 void sched_request_timeout_ms(long unsigned ms, struct sched *s);
 int sched_request_barrier(struct timeval *barrier, struct sched *s);
 int sched_request_barrier_or_min_delay(struct timeval *barrier, struct sched *s);
+void sched_monitor_readfd(int fd, struct sched *s);
+void sched_monitor_writefd(int fd, struct sched *s);
+bool sched_read_ok(int fd, const struct sched *s);
+bool sched_write_ok(int fd, const struct sched *s);