sync code with last improvements from OpenBSD

xserver/os/ospoll.h

@@ -0,0 +1,142 @@
+/*
+ * Copyright © 2016 Keith Packard
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#ifndef _OSPOLL_H_
+#define _OSPOLL_H_
+
+/* Forward declaration */
+struct ospoll;
+
+/**
+ * ospoll_wait trigger mode
+ *
+ * @ospoll_trigger_edge
+ *      Trigger only when going from no data available
+ *      to data available.
+ *
+ * @ospoll_trigger_level
+ *      Trigger whenever there is data available
+ */
+enum ospoll_trigger {
+    ospoll_trigger_edge,
+    ospoll_trigger_level
+};
+
+/**
+ * Create a new ospoll structure
+ */
+struct ospoll *
+ospoll_create(void);
+
+/**
+ * Destroy an ospoll structure
+ *
+ * @param       ospoll          ospoll to destroy
+ */
+void
+ospoll_destroy(struct ospoll *ospoll);
+
+/**
+ * Add a file descriptor to monitor
+ *
+ * @param       ospoll          ospoll to add to
+ * @param       fd              File descriptor to monitor
+ * @param       trigger         Trigger mode for ospoll_wait
+ * @param       callback        Function to call when triggered
+ * @param       data            Extra data to pass callback
+ */
+Bool
+ospoll_add(struct ospoll *ospoll, int fd,
+           enum ospoll_trigger trigger,
+           void (*callback)(int fd, int xevents, void *data),
+           void *data);
+
+/**
+ * Remove a monitored file descriptor
+ *
+ * @param       ospoll          ospoll to remove from
+ * @param       fd              File descriptor to stop monitoring
+ */
+void
+ospoll_remove(struct ospoll *ospoll, int fd);
+
+/**
+ * Listen on additional events
+ *
+ * @param       ospoll          ospoll monitoring fd
+ * @param       fd              File descriptor to change
+ * @param       events          Additional events to trigger on
+ */
+void
+ospoll_listen(struct ospoll *ospoll, int fd, int xevents);
+
+/**
+ * Stop listening on events
+ *
+ * @param       ospoll          ospoll monitoring fd
+ * @param       fd              File descriptor to change
+ * @param       events          events to stop triggering on
+ */
+void
+ospoll_mute(struct ospoll *ospoll, int fd, int xevents);
+
+/**
+ * Wait for events
+ *
+ * @param       ospoll          ospoll to wait on
+ * @param       timeout         < 0 wait forever
+ *                              = 0 check and return
+ *                              > 0 timeout in milliseconds
+ * @return      < 0 error
+ *              = 0 timeout
+ *              > 0 number of events delivered
+ */
+int
+ospoll_wait(struct ospoll *ospoll, int timeout);
+
+/**
+ * Reset edge trigger status
+ *
+ * @param       ospoll          ospoll monitoring fd
+ * @param       fd              file descriptor
+ *
+ * ospoll_reset_events resets the state of an edge-triggered
+ * fd so that ospoll_wait calls will report events again.
+ *
+ * Call this after a read/recv operation reports no more data available.
+ */
+void
+ospoll_reset_events(struct ospoll *ospoll, int fd);
+
+/**
+ * Fetch the data associated with an fd
+ *
+ * @param       ospoll          ospoll monitoring fd
+ * @param       fd              file descriptor
+ *
+ * @return      data parameter passed to ospoll_add call on
+ *              this file descriptor
+ */
+void *
+ospoll_data(struct ospoll *ospoll, int fd);
+
+#endif /* _OSPOLL_H_ */