[PATCH weston 2/8] shared: Add helpers to convert between protocol data and timespec

Alexandros Frantzis alexandros.frantzis at collabora.com
Mon Dec 4 13:34:02 UTC 2017


Add helpers to safely convert between struct timespec values and
tv_sec_hi, tv_sec_lo, tv_nsec triplets used for sending high-resolution
timestamp data over the wayland protocol. Replace existing conversion
code with the helper functions.

Signed-off-by: Alexandros Frantzis <alexandros.frantzis at collabora.com>
---
 clients/presentation-shm.c |  9 +------
 libweston/compositor.c     |  9 ++++---
 shared/timespec-util.h     | 39 +++++++++++++++++++++++++++
 tests/presentation-test.c  |  9 +------
 tests/timespec-test.c      | 66 ++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 112 insertions(+), 20 deletions(-)

diff --git a/clients/presentation-shm.c b/clients/presentation-shm.c
index c9fb66cc..d6a939e5 100644
--- a/clients/presentation-shm.c
+++ b/clients/presentation-shm.c
@@ -39,6 +39,7 @@
 #include <wayland-client.h>
 #include "shared/helpers.h"
 #include "shared/zalloc.h"
+#include "shared/timespec-util.h"
 #include "shared/os-compatibility.h"
 #include "presentation-time-client-protocol.h"
 
@@ -383,14 +384,6 @@ timespec_to_ms(const struct timespec *ts)
 	return (uint32_t)ts->tv_sec * 1000 + ts->tv_nsec / 1000000;
 }
 
-static void
-timespec_from_proto(struct timespec *tm, uint32_t tv_sec_hi,
-		    uint32_t tv_sec_lo, uint32_t tv_nsec)
-{
-	tm->tv_sec = ((uint64_t)tv_sec_hi << 32) + tv_sec_lo;
-	tm->tv_nsec = tv_nsec;
-}
-
 static int
 timespec_diff_to_usec(const struct timespec *a, const struct timespec *b)
 {
diff --git a/libweston/compositor.c b/libweston/compositor.c
index 7d7a17ed..083664fd 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -341,7 +341,9 @@ weston_presentation_feedback_present(
 {
 	struct wl_client *client = wl_resource_get_client(feedback->resource);
 	struct wl_resource *o;
-	uint64_t secs;
+	uint32_t tv_sec_hi;
+	uint32_t tv_sec_lo;
+	uint32_t tv_nsec;
 
 	wl_resource_for_each(o, &output->resource_list) {
 		if (wl_resource_get_client(o) != client)
@@ -350,10 +352,9 @@ weston_presentation_feedback_present(
 		wp_presentation_feedback_send_sync_output(feedback->resource, o);
 	}
 
-	secs = ts->tv_sec;
+	timespec_to_proto(ts, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
 	wp_presentation_feedback_send_presented(feedback->resource,
-						secs >> 32, secs & 0xffffffff,
-						ts->tv_nsec,
+						tv_sec_hi, tv_sec_lo, tv_nsec,
 						refresh_nsec,
 						seq >> 32, seq & 0xffffffff,
 						flags | feedback->psf_flags);
diff --git a/shared/timespec-util.h b/shared/timespec-util.h
index a10edf5b..c734accd 100644
--- a/shared/timespec-util.h
+++ b/shared/timespec-util.h
@@ -175,6 +175,30 @@ timespec_to_usec(const struct timespec *a)
 	return (int64_t)a->tv_sec * 1000000 + a->tv_nsec / 1000;
 }
 
+/* Convert timespec to protocol data
+ *
+ * \param a timespec
+ * \param tv_sec_hi[out] the high bytes of the seconds part
+ * \param tv_sec_lo[out] the low bytes of the seconds part
+ * \param tv_nsec[out] the nanoseconds part
+ *
+ * The timespec is normalized before being converted to protocol data.
+ */
+static inline void
+timespec_to_proto(const struct timespec *a, uint32_t *tv_sec_hi,
+                  uint32_t *tv_sec_lo, uint32_t *tv_nsec)
+{
+	struct timespec r;
+
+	timespec_normalize(&r, a);
+
+	/* We check the size of tv_sec, so that we shift only if the size
+	 * is 64-bits, in order to avoid sign extension on 32-bit systems. */
+	*tv_sec_hi = sizeof(r.tv_sec) == 8 ? (int64_t)r.tv_sec >> 32 : 0;
+	*tv_sec_lo = r.tv_sec;
+	*tv_nsec = r.tv_nsec;
+}
+
 /* Convert nanoseconds to timespec
  *
  * \param a timespec
@@ -209,6 +233,21 @@ timespec_from_msec(struct timespec *a, int64_t b)
 	timespec_from_nsec(a, b * 1000000);
 }
 
+/* Convert protocol data to timespec
+ *
+ * \param a[out] timespec
+ * \param tv_sec_hi the high bytes of seconds part
+ * \param tv_sec_lo the low bytes of seconds part
+ * \param tv_nsec the nanoseconds part
+ */
+static inline void
+timespec_from_proto(struct timespec *a, uint32_t tv_sec_hi,
+                    uint32_t tv_sec_lo, uint32_t tv_nsec)
+{
+	a->tv_sec = ((uint64_t)tv_sec_hi << 32) + tv_sec_lo;
+	a->tv_nsec = tv_nsec;
+}
+
 /* Check if a timespec is zero
  *
  * \param a timespec
diff --git a/tests/presentation-test.c b/tests/presentation-test.c
index f12f8eef..f6ffe480 100644
--- a/tests/presentation-test.c
+++ b/tests/presentation-test.c
@@ -34,6 +34,7 @@
 
 #include "shared/helpers.h"
 #include "shared/xalloc.h"
+#include "shared/timespec-util.h"
 #include "weston-test-client-helper.h"
 #include "presentation-time-client-protocol.h"
 
@@ -85,14 +86,6 @@ struct feedback {
 	uint32_t flags;
 };
 
-static void
-timespec_from_proto(struct timespec *tm, uint32_t tv_sec_hi,
-		    uint32_t tv_sec_lo, uint32_t tv_nsec)
-{
-	tm->tv_sec = ((uint64_t)tv_sec_hi << 32) + tv_sec_lo;
-	tm->tv_nsec = tv_nsec;
-}
-
 static void
 feedback_sync_output(void *data,
 		     struct wp_presentation_feedback *presentation_feedback,
diff --git a/tests/timespec-test.c b/tests/timespec-test.c
index 8c2296d1..9000295a 100644
--- a/tests/timespec-test.c
+++ b/tests/timespec-test.c
@@ -38,6 +38,12 @@
 #include "shared/helpers.h"
 #include "zunitc/zunitc.h"
 
+static uint32_t
+get_tv_sec_hi(const struct timespec *ts)
+{
+	return sizeof(ts->tv_sec) == 8 ? (int64_t)ts->tv_sec >> 32 : 0;
+}
+
 ZUC_TEST(timespec_test, timespec_normalize)
 {
 	struct timespec a, r;
@@ -143,6 +149,49 @@ ZUC_TEST(timespec_test, timespec_to_msec)
 	ZUC_ASSERT_EQ(timespec_to_msec(&a), (4000ULL) + 4);
 }
 
+ZUC_TEST(timespec_test, timespec_to_proto)
+{
+	struct timespec a;
+	uint32_t tv_sec_hi;
+	uint32_t tv_sec_lo;
+	uint32_t tv_nsec;
+
+	a.tv_sec = 0;
+	a.tv_nsec = 0;
+	timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+	ZUC_ASSERT_EQ(0, tv_sec_hi);
+	ZUC_ASSERT_EQ(0, tv_sec_lo);
+	ZUC_ASSERT_EQ(0, tv_nsec);
+
+	a.tv_sec = 1234;
+	a.tv_nsec = NSEC_PER_SEC - 1;
+	timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+	ZUC_ASSERT_EQ(0, tv_sec_hi);
+	ZUC_ASSERT_EQ(1234, tv_sec_lo);
+	ZUC_ASSERT_EQ(NSEC_PER_SEC - 1, tv_nsec);
+
+	a.tv_sec = 1234;
+	a.tv_nsec = NSEC_PER_SEC + 1;
+	timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+	ZUC_ASSERT_EQ(0, tv_sec_hi);
+	ZUC_ASSERT_EQ(1235, tv_sec_lo);
+	ZUC_ASSERT_EQ(1, tv_nsec);
+
+	a.tv_sec = (time_t)0x7000123470005678LL;
+	a.tv_nsec = 1;
+	timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+	ZUC_ASSERT_EQ(get_tv_sec_hi(&a), tv_sec_hi);
+	ZUC_ASSERT_EQ(0x70005678, tv_sec_lo);
+	ZUC_ASSERT_EQ(1, tv_nsec);
+
+	a.tv_sec = (time_t)0x8000123480005678LL;
+	a.tv_nsec = -1;
+	timespec_to_proto(&a, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
+	ZUC_ASSERT_EQ(get_tv_sec_hi(&a), tv_sec_hi);
+	ZUC_ASSERT_EQ(0x80005678, tv_sec_lo);
+	ZUC_ASSERT_EQ((uint32_t)-1, tv_nsec);
+}
+
 ZUC_TEST(timespec_test, millihz_to_nsec)
 {
 	ZUC_ASSERT_EQ(millihz_to_nsec(60000), 16666666);
@@ -302,6 +351,23 @@ ZUC_TEST(timespec_test, timespec_from_msec)
 	ZUC_ASSERT_EQ(1000000, a.tv_nsec);
 }
 
+ZUC_TEST(timespec_test, timespec_from_proto)
+{
+	struct timespec a;
+
+	timespec_from_proto(&a, 0, 0, 0);
+	ZUC_ASSERT_EQ(0, a.tv_sec);
+	ZUC_ASSERT_EQ(0, a.tv_nsec);
+
+	timespec_from_proto(&a, 0, 1234, 9999);
+	ZUC_ASSERT_EQ(1234, a.tv_sec);
+	ZUC_ASSERT_EQ(9999, a.tv_nsec);
+
+	timespec_from_proto(&a, 0x1234, 0x5678, 1);
+	ZUC_ASSERT_EQ(0x0000123400005678LL, a.tv_sec);
+	ZUC_ASSERT_EQ(1, a.tv_nsec);
+}
+
 ZUC_TEST(timespec_test, timespec_is_zero)
 {
 	struct timespec zero = { 0 };
-- 
2.14.1



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