Add a timer subsystem

Currently we are using DIY timers in the touchpad softbutton and tap handling
code, and at least the softbutton code gets its wrong. It uses one timer-fd
per touchpad to set a timeout per touch, which means that if a timeout is
set for 100ms from now for touch 1, and then 50 ms later touch 2 sets a timeout
for 200 ms from now, then the timeout for touch 1 will come 150 ms too late.

This commits adds a proper timer subsystem so that we've one place to deal
with timer handling, and so that we can only get it wrong (well hopefully
we get it right) in one place.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

src/Makefile.am

@@ -21,6 +21,8 @@ libinput_la_SOURCES =			\
 	path.c				\
 	udev-seat.c			\
 	udev-seat.h			\
+	timer.c				\
+	timer.h				\
 	../include/linux/input.h
 
 libinput_la_LIBADD = $(MTDEV_LIBS) \

src/libinput-private.h

@@ -28,6 +28,8 @@
 #include "libinput.h"
 #include "libinput-util.h"
 
+struct libinput_source;
+
 struct libinput_interface_backend {
 	int (*resume)(struct libinput *libinput);
 	void (*suspend)(struct libinput *libinput);
@@ -40,6 +42,12 @@ struct libinput {
 
 	struct list seat_list;
 
+	struct {
+		struct list list;
+		struct libinput_source *source;
+		int fd;
+	} timer;
+
 	struct libinput_event **events;
 	size_t events_count;
 	size_t events_len;
@@ -79,7 +87,6 @@ struct libinput_device {
 
 typedef void (*libinput_source_dispatch_t)(void *data);
 
-struct libinput_source;
 
 #define log_debug(...) log_msg(LIBINPUT_LOG_PRIORITY_DEBUG, __VA_ARGS__)
 #define log_info(...) log_msg(LIBINPUT_LOG_PRIORITY_INFO, __VA_ARGS__)

src/libinput.c

@@ -33,6 +33,7 @@
 #include "libinput.h"
 #include "libinput-private.h"
 #include "evdev.h"
+#include "timer.h"
 
 struct libinput_source {
 	libinput_source_dispatch_t dispatch;
@@ -485,6 +486,12 @@ libinput_init(struct libinput *libinput,
 	list_init(&libinput->source_destroy_list);
 	list_init(&libinput->seat_list);
 
+	if (libinput_timer_subsys_init(libinput) != 0) {
+		free(libinput->events);
+		close(libinput->epoll_fd);
+		return -1;
+	}
+
 	return 0;
 }
 
@@ -521,8 +528,6 @@ libinput_destroy(struct libinput *libinput)
 	while ((event = libinput_get_event(libinput)))
 	       libinput_event_destroy(event);
 
-	libinput_drop_destroyed_sources(libinput);
-
 	free(libinput->events);
 
 	list_for_each_safe(seat, next_seat, &libinput->seat_list, link) {
@@ -534,6 +539,8 @@ libinput_destroy(struct libinput *libinput)
 		libinput_seat_destroy(seat);
 	}
 
+	libinput_timer_subsys_destroy(libinput);
+	libinput_drop_destroyed_sources(libinput);
 	close(libinput->epoll_fd);
 	free(libinput);
 }

src/timer.c

@@ -0,0 +1,144 @@
+/*
+ * Copyright © 2014 Red Hat, Inc.
+ *
+ * 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.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/timerfd.h>
+#include <unistd.h>
+
+#include "libinput-private.h"
+#include "timer.h"
+
+void
+libinput_timer_init(struct libinput_timer *timer, struct libinput *libinput,
+		    void (*timer_func)(uint64_t now, void *timer_func_data),
+		    void *timer_func_data)
+{
+	timer->libinput = libinput;
+	timer->timer_func = timer_func;
+	timer->timer_func_data = timer_func_data;
+}
+
+static void
+libinput_timer_arm_timer_fd(struct libinput *libinput)
+{
+	int r;
+	struct libinput_timer *timer;
+	struct itimerspec its = { { 0 }, { 0 } };
+	uint64_t earliest_expire = UINT64_MAX;
+
+	list_for_each(timer, &libinput->timer.list, link) {
+		if (timer->expire < earliest_expire)
+			earliest_expire = timer->expire;
+	}
+
+	if (earliest_expire != UINT64_MAX) {
+		its.it_value.tv_sec = earliest_expire / 1000;
+		its.it_value.tv_nsec = (earliest_expire % 1000) * 1000 * 1000;
+	}
+
+	r = timerfd_settime(libinput->timer.fd, TFD_TIMER_ABSTIME, &its, NULL);
+	if (r)
+		log_error("timerfd_settime error: %s\n", strerror(errno));
+}
+
+void
+libinput_timer_set(struct libinput_timer *timer, uint64_t expire)
+{
+	assert(expire);
+
+	if (!timer->expire)
+		list_insert(&timer->libinput->timer.list, &timer->link);
+
+	timer->expire = expire;
+	libinput_timer_arm_timer_fd(timer->libinput);
+}
+
+void
+libinput_timer_cancel(struct libinput_timer *timer)
+{
+	if (!timer->expire)
+		return;
+
+	timer->expire = 0;
+	list_remove(&timer->link);
+	libinput_timer_arm_timer_fd(timer->libinput);
+}
+
+static void
+libinput_timer_handler(void *data)
+{
+	struct libinput *libinput = data;
+	struct libinput_timer *timer, *tmp;
+	struct timespec ts;
+	uint64_t now;
+	int r;
+
+	r = clock_gettime(CLOCK_MONOTONIC, &ts);
+	if (r) {
+		log_error("clock_gettime error: %s\n", strerror(errno));
+		return;
+	}
+
+	now = ts.tv_sec * 1000ULL + ts.tv_nsec / 1000000;
+
+	list_for_each_safe(timer, tmp, &libinput->timer.list, link) {
+		if (timer->expire <= now) {
+			/* Clear the timer before calling timer_func,
+			   as timer_func may re-arm it */
+			libinput_timer_cancel(timer);
+			timer->timer_func(now, timer->timer_func_data);
+		}
+	}
+}
+
+int
+libinput_timer_subsys_init(struct libinput *libinput)
+{
+	libinput->timer.fd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
+	if (libinput->timer.fd < 0)
+		return -1;
+
+	list_init(&libinput->timer.list);
+
+	libinput->timer.source = libinput_add_fd(libinput,
+						 libinput->timer.fd,
+						 libinput_timer_handler,
+						 libinput);
+	if (!libinput->timer.source) {
+		close(libinput->timer.fd);
+		return -1;
+	}
+
+	return 0;
+}
+
+void
+libinput_timer_subsys_destroy(struct libinput *libinput)
+{
+	/* All timer users should have destroyed their timers now */
+	assert(list_empty(&libinput->timer.list));
+
+	libinput_remove_source(libinput, libinput->timer.source);
+	close(libinput->timer.fd);
+}

src/timer.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright © 2014 Red Hat, Inc.
+ *
+ * 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 TIMER_H
+#define TIMER_H
+
+#include <stdint.h>
+
+struct libinput;
+
+struct libinput_timer {
+	struct libinput *libinput;
+	struct list link;
+	uint64_t expire; /* in absolute ms CLOCK_MONOTONIC */
+	void (*timer_func)(uint64_t now, void *timer_func_data);
+	void *timer_func_data;
+};
+
+void
+libinput_timer_init(struct libinput_timer *timer, struct libinput *libinput,
+		    void (*timer_func)(uint64_t now, void *timer_func_data),
+		    void *timer_func_data);
+
+/* Set timer expire time, in absolute ms CLOCK_MONOTONIC */
+void
+libinput_timer_set(struct libinput_timer *timer, uint64_t expire);
+
+void
+libinput_timer_cancel(struct libinput_timer *timer);
+
+int
+libinput_timer_subsys_init(struct libinput *libinput);
+
+void
+libinput_timer_subsys_destroy(struct libinput *libinput);
+
+#endif