X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=sched.h;h=f89b89ffc012551e17febc9de463882eb5c678b6;hb=742c8b3f79a59278ced71e1855da1846b157b494;hp=ada1cc106c068706fc175cc883450c17a237f4b7;hpb=68630d8b55d688a7c7ce116951c310150aa9c166;p=paraslash.git

diff --git a/sched.h b/sched.h
index ada1cc10..f89b89ff 100644
--- a/sched.h
+++ b/sched.h
@@ -1,8 +1,4 @@
-/*
- * Copyright (C) 2006 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. */
 
@@ -15,12 +11,14 @@
  * 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.
+ *
+ * \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;
+	/** Initial value (in milliseconds) before any pre_select call. */
+	int default_timeout;
+	/** The timeout (also in milliseconds) for the next select call. */
+	int timeout;
 	/** fds that should be watched for readability. */
 	fd_set rfds;
 	/** fds that should be watched for writability. */
@@ -28,7 +26,7 @@ struct sched {
 	/** 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 *);
+	int (*select_function)(int, fd_set *, fd_set *, int timeout);
 	/** Tasks which have been registered to the scheduler. */
 	struct list_head task_list;
 };
@@ -40,18 +38,27 @@ 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.
+	 *
+	 * 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.
 	 *
-	 * Its purpose is to add file descriptors to the fd sets of the
-	 * scheduler and to decrease the select timeout if necessary.
+	 * \sa \ref time.c.
 	 */
 	void (*pre_select)(struct sched *s, void *context);
 	/**
-	 * The mandatory post select method.
+	 * Perform I/O on file descriptors which are ready for I/O.
 	 *
-	 * 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.
+	 * 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.
+	 *
+	 * If this function returns a negative value, the scheduler unregisters
+	 * the task.
 	 */
 	int (*post_select)(struct sched *s, void *context);
 	/**
@@ -84,3 +91,15 @@ 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);
+
+static inline bool sched_read_ok(int fd, const struct sched *s)
+{
+	return FD_ISSET(fd, &s->rfds);
+}
+
+static inline bool sched_write_ok(int fd, const struct sched *s)
+{
+	return FD_ISSET(fd, &s->wfds);
+}