tools/record: fix broken autorestart for timeouts >=5s

The autorestart feature used the epoll timeout for detecting when no
events happend. This conflicts with our wall clock timerfd (to print the
current time every 5s) which is hooked into the same epoll. Any
autorestart timeout >=5s would get that timerfd fired which is
interpreted as events and thus prevents the autorestart from closing the
file.

Fix this by removing the timerfd and instead print the wall clock
time whenever we get events and it's past a delta. This means we can
also drop the hacks to remember if we did have events since the last
timer to avoid spamming empty logs with "Current time: ..." lines.

Closes #1291

(cherry picked from commit 31658a34ff)

Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1482>

tools/libinput-record.c

@@ -38,7 +38,6 @@
 #include <sys/epoll.h>
 #include <sys/signalfd.h>
 #include <sys/stat.h>
-#include <sys/timerfd.h>
 #include <sys/utsname.h>
 #include <time.h>
 #include <unistd.h>
@@ -130,8 +129,7 @@ struct record_context {
 	struct list sources;
 
 	struct {
-		bool had_events_since_last_time;
+		usec_t last_wall_time;
-		bool skipped_timer_print;
 	} timestamps;
 
 	bool had_events;
@@ -2071,21 +2069,6 @@ print_wall_time(struct record_context *ctx)
 	}
 }
 
-static void
-arm_timer(int timerfd)
-{
-	time_t t = time(NULL);
-	struct tm tm;
-	struct itimerspec interval = {
-		.it_value = { 0, 0 },
-		.it_interval = { 5, 0 },
-	};
-
-	localtime_r(&t, &tm);
-	interval.it_value.tv_sec = 5 - (tm.tm_sec % 5);
-	timerfd_settime(timerfd, 0, &interval, NULL);
-}
-
 static struct source *
 add_source(struct record_context *ctx,
 	   int fd,
@@ -2131,35 +2114,12 @@ signalfd_dispatch(struct record_context *ctx, int fd, void *data)
 	ctx->stop = true;
 }
 
-static void
-timefd_dispatch(struct record_context *ctx, int fd, void *data)
-{
-	char discard[64];
-
-	(void)read(fd, discard, sizeof(discard));
-
-	if (ctx->timestamps.had_events_since_last_time) {
-		print_wall_time(ctx);
-		ctx->timestamps.had_events_since_last_time = false;
-		ctx->timestamps.skipped_timer_print = false;
-	} else {
-		ctx->timestamps.skipped_timer_print = true;
-	}
-}
-
 static void
 evdev_dispatch(struct record_context *ctx, int fd, void *data)
 {
 	struct record_device *this_device = data;
 
-	if (ctx->timestamps.skipped_timer_print) {
-		print_wall_time(ctx);
-		ctx->timestamps.skipped_timer_print = false;
-	}
-
 	ctx->had_events = true;
-	ctx->timestamps.had_events_since_last_time = true;
-	now_in_us(&ctx->timestamps.last_event_time);
 
 	handle_events(ctx, this_device);
 }
@@ -2172,7 +2132,6 @@ libinput_ctx_dispatch(struct record_context *ctx, int fd, void *data)
 	 * are already processed in handle_events */
 	libinput_dispatch(ctx->libinput);
 	handle_libinput_events(ctx, ctx->first_device, true);
-	now_in_us(&ctx->timestamps.last_event_time);
 }
 
 static void
@@ -2181,9 +2140,7 @@ hidraw_dispatch(struct record_context *ctx, int fd, void *data)
 	struct hidraw *hidraw = data;
 
 	ctx->had_events = true;
-	ctx->timestamps.had_events_since_last_time = true;
 	handle_hidraw(hidraw);
-	now_in_us(&ctx->timestamps.last_event_time);
 }
 
 static int
@@ -2201,10 +2158,20 @@ dispatch_sources(struct record_context *ctx)
 	if (count < 0)
 		return -errno;
 
+	if (count > 0) {
+		usec_t now = usec_from_now();
+		usec_t dt = usec_delta(now, ctx->timestamps.last_wall_time);
+		if (usec_cmp(dt, usec_from_seconds(5)) > 0) {
+			ctx->timestamps.last_wall_time = now;
+			print_wall_time(ctx);
+		}
+	}
+
 	for (i = 0; i < count; ++i) {
 		source = ep[i].data.ptr;
 		if (source->fd == -1)
 			continue;
+
 		source->dispatch(ctx, source->fd, source->user_data);
 	}
 
@@ -2218,7 +2185,7 @@ mainloop(struct record_context *ctx)
 	struct source *source;
 	struct record_device *d = NULL;
 	sigset_t mask;
-	int sigfd, timerfd;
+	int sigfd;
 
 	assert(!list_empty(&ctx->devices));
 
@@ -2233,10 +2200,6 @@ mainloop(struct record_context *ctx)
 	sigfd = signalfd(-1, &mask, SFD_NONBLOCK);
 	add_source(ctx, sigfd, signalfd_dispatch, NULL);
 
-	timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC | TFD_NONBLOCK);
-	add_source(ctx, timerfd, timefd_dispatch, NULL);
-	arm_timer(timerfd);
-
 	list_for_each(d, &ctx->devices, link) {
 		struct hidraw *hidraw;
 
@@ -2296,6 +2259,8 @@ mainloop(struct record_context *ctx)
 			print_device_description(d);
 			iprintf(d->fp, I_DEVICE, "events:\n");
 		}
+
+		ctx->timestamps.last_wall_time = usec_from_now();
 		print_wall_time(ctx);
 
 		if (ctx->libinput) {
@@ -2659,6 +2624,7 @@ main(int argc, char **argv)
 	struct record_context ctx = {
 		.timeout = usec_from_uint64_t(0),
 		.show_keycodes = false,
+		.timestamps.last_wall_time = usec_from_uint64_t(0),
 	};
 	struct option opts[] = {
 		{ "autorestart", required_argument, 0, OPT_AUTORESTART },