/*
- * Copyright (c) 2008 Nicira Networks.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
/* High-level wrapper around the "poll" system call.
*
- * Intended usage is for the program's main loop to go about its business
+ * The intended usage is for each thread's main loop to go about its business
* servicing whatever events it needs to. Then, when it runs out of immediate
* tasks, it calls each subordinate module's "wait" function, which in turn
* calls one (or more) of the functions poll_fd_wait(), poll_immediate_wake(),
* occurs. Then the main loop calls poll_block(), which blocks until one of
* the registered events happens.
*
- * There is also some support for autonomous subroutines that are executed by
- * poll_block() when a file descriptor becomes ready. To prevent these
- * routines from starving if events are continuously ready, the application
- * should bound the amount of work it does between poll_block() calls. */
-
+ *
+ * Thread-safety
+ * =============
+ *
+ * The poll set is per-thread, so all functions in this module are thread-safe.
+ */
#ifndef POLL_LOOP_H
#define POLL_LOOP_H 1
#include <poll.h>
+#include "util.h"
-struct poll_waiter;
+#ifdef __cplusplus
+extern "C" {
+#endif
-/* Schedule events to wake up the following poll_block(). */
-struct poll_waiter *poll_fd_wait(int fd, short int events);
-void poll_timer_wait(int msec);
-void poll_immediate_wake(void);
+
+/* Schedule events to wake up the following poll_block().
+ *
+ * The poll_loop logs the 'where' argument to each function at "debug" level
+ * when an event causes a wakeup. Ordinarily, it is automatically filled in
+ * with the location in the source of the call, and the caller should therefore
+ * omit it. But, if the function you are implementing is very generic, so that
+ * its location in the source would not be very helpful for debugging, you can
+ * avoid the macro expansion and pass a different argument, e.g.:
+ * (poll_fd_wait)(fd, events, where);
+ * See timer_wait() for an example.
+ */
+void poll_fd_wait(int fd, short int events, const char *where);
+#define poll_fd_wait(fd, events) poll_fd_wait(fd, events, SOURCE_LOCATOR)
+
+void poll_timer_wait(long long int msec, const char *where);
+#define poll_timer_wait(msec) poll_timer_wait(msec, SOURCE_LOCATOR)
+
+void poll_timer_wait_until(long long int msec, const char *where);
+#define poll_timer_wait_until(msec) poll_timer_wait_until(msec, SOURCE_LOCATOR)
+
+void poll_immediate_wake(const char *where);
+#define poll_immediate_wake() poll_immediate_wake(SOURCE_LOCATOR)
/* Wait until an event occurs. */
void poll_block(void);
-/* Autonomous function callbacks. */
-typedef void poll_fd_func(int fd, short int revents, void *aux);
-struct poll_waiter *poll_fd_callback(int fd, short int events,
- poll_fd_func *, void *aux);
-
-/* Cancel a file descriptor callback or event. */
-void poll_cancel(struct poll_waiter *);
+#ifdef __cplusplus
+}
+#endif
#endif /* poll-loop.h */