evdev: print a human time for ratelimit tests

No point in printing an interval of e.g. 2h as milliseconds, let's convert
this to something human-readable.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

src/evdev.h

@@ -814,12 +814,17 @@ evdev_log_msg_ratelimit(struct evdev_device *device,
 	log_msg_va(evdev_libinput_context(device), priority, buf, args);
 	va_end(args);
 
-	if (state == RATELIMIT_THRESHOLD)
+	if (state == RATELIMIT_THRESHOLD) {
+		struct human_time ht = to_human_time(ratelimit->interval);
 		evdev_log_msg(device,
 			      priority,
-			      "WARNING: log rate limit exceeded (%d msgs per %dms). Discarding future messages.\n",
+			      "WARNING: log rate limit exceeded (%d msgs per %d%s). "
+			      "Discarding future messages.\n",
 			      ratelimit->burst,
-			      us2ms(ratelimit->interval));
+			      ht.value,
+			      ht.unit);
+
+	}
 }
 
 #define evdev_log_debug(d_, ...) evdev_log_msg((d_), LIBINPUT_LOG_PRIORITY_DEBUG, __VA_ARGS__)

src/util-time.h

@@ -25,11 +25,14 @@
 
 #include "config.h"
 
+#include <assert.h>
 #include <time.h>
 #include <stdint.h>
 #include <unistd.h>
 #include <linux/input.h>
 
+#include "util-macros.h"
+
 static inline void
 msleep(unsigned int ms)
 {
@@ -82,3 +85,42 @@ us2tv(uint64_t time)
 
 	return tv;
 }
+
+struct human_time {
+	unsigned int value;
+	const char *unit;
+};
+
+/**
+ * Converts a time delta in µs to a human-readable time like "2h" or "4d"
+ */
+static inline struct human_time
+to_human_time(uint64_t us)
+{
+	struct human_time t;
+	struct c {
+		const char *unit;
+		unsigned int change_from_previous;
+		uint64_t limit;
+	} conversion[] = {
+		{"us", 1, 5000},
+		{"ms", 1000, 5000},
+		{"s", 1000, 120},
+		{"min", 60, 120},
+		{"h", 60, 48},
+		{"d", 24, ~0},
+	};
+	struct c *c;
+	uint64_t value = us;
+
+	ARRAY_FOR_EACH(conversion, c) {
+		value = value/c->change_from_previous;
+		if (value < c->limit) {
+			t.unit = c->unit;
+			t.value = value;
+			return t;
+		}
+	}
+
+	assert(!"We should never get here");
+}

test/test-utils.c

@@ -633,6 +633,37 @@ START_TEST(time_conversion)
 }
 END_TEST
 
+START_TEST(human_time)
+{
+	struct ht_tests {
+		uint64_t interval;
+		unsigned int value;
+		const char *unit;
+	} tests[] = {
+		{ 0, 0, "us" },
+		{ 123, 123, "us" },
+		{ ms2us(5), 5, "ms" },
+		{ ms2us(100), 100, "ms" },
+		{ s2us(5), 5, "s" },
+		{ s2us(100), 100, "s" },
+		{ s2us(120), 2, "min" },
+		{ 5 * s2us(60), 5, "min" },
+		{ 120 * s2us(60), 2, "h" },
+		{ 5 * 60 * s2us(60), 5, "h" },
+		{ 48 * 60 * s2us(60), 2, "d" },
+		{ 1000 * 24 * 60 * s2us(60), 1000, "d" },
+		{ 0, 0, NULL },
+	};
+	for (int i = 0; tests[i].unit != NULL; i++) {
+		struct human_time ht;
+
+		ht = to_human_time(tests[i].interval);
+		ck_assert_int_eq(ht.value, tests[i].value);
+		ck_assert_str_eq(ht.unit, tests[i].unit);
+	}
+}
+END_TEST
+
 struct atoi_test {
 	char *str;
 	bool success;
@@ -1178,6 +1209,7 @@ litest_utils_suite(void)
 	tcase_add_test(tc, strjoin_test);
 	tcase_add_test(tc, strstrip_test);
 	tcase_add_test(tc, time_conversion);
+	tcase_add_test(tc, human_time);
 
 	tcase_add_test(tc, list_test_insert);
 	tcase_add_test(tc, list_test_append);