[vlc-devel] [PATCH v2 2/4] compat: add clock_nanosleep for darwin

[Marvin Scholz]

---
 compat/clock_nanosleep.c | 109 +++++++++++++++++++++++++++++++++++++++
 configure.ac             |   4 +-
 include/vlc_fixups.h     |   7 +++
 3 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 compat/clock_nanosleep.c

diff --git a/compat/clock_nanosleep.c b/compat/clock_nanosleep.c
new file mode 100644
index 0000000000..aea702dfa9
--- /dev/null
+++ b/compat/clock_nanosleep.c
@@ -0,0 +1,109 @@
+/*****************************************************************************
+ * clock_nanosleep.c: POSIX clock_nanosleep() replacement
+ *****************************************************************************
+ * Copyright © 2020 VLC authors and VideoLAN
+ *
+ * Author: Marvin Scholz <epirat07 at gmail dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef __APPLE__
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <assert.h>
+#include <pthread.h>
+#include <sys/errno.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/sysctl.h>
+#include <mach/clock_types.h>
+
+#define timespecs_sub(tsa, tsb, tsr)                                \
+    do {                                                            \
+            (tsr)->tv_sec = (tsa)->tv_sec - (tsb)->tv_sec;          \
+            (tsr)->tv_nsec = (tsa)->tv_nsec - (tsb)->tv_nsec;       \
+            if ((tsr)->tv_nsec < 0) {                               \
+                    (tsr)->tv_sec--;                                \
+                    (tsr)->tv_nsec += NSEC_PER_SEC;                 \
+            }                                                       \
+    } while (0)
+
+#define timespec_zero(ts) \
+    ((ts)->tv_sec == 0 && (ts)->tv_nsec == 0)
+
+int clock_nanosleep(clockid_t clock_id, int flags,
+        const struct timespec *rqtp, struct timespec *rmtp)
+{
+    // Validate timespec
+    if (rqtp == NULL || rqtp->tv_sec < 0 ||
+            rqtp->tv_nsec < 0 || (unsigned long)rqtp->tv_nsec >= NSEC_PER_SEC) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    // Validate clock
+    switch (clock_id) {
+        case CLOCK_MONOTONIC:
+        case CLOCK_REALTIME:
+            break;
+        default:
+            errno = EINVAL;
+            return -1;
+    }
+
+    if (flags == TIMER_ABSTIME) {
+        struct timespec ts_rel;
+        struct timespec ts_now;
+
+        do {
+            // Get current time with requested clock
+            if (clock_gettime(clock_id, &ts_now) != 0)
+                return -1;
+
+            // Calculate relative timespec
+            timespecs_sub(rqtp, &ts_now, &ts_rel);
+
+            // Check if time already elapsed
+            if (ts_rel.tv_sec < 0 || timespec_zero(&ts_rel)) {
+                pthread_testcancel();
+                return 0;
+            }
+
+            // "The absolute clock_nanosleep() function has no effect on the
+            // structure referenced by rmtp", so do not pass rmtp here
+        } while (nanosleep(&ts_rel, NULL) == 0);
+
+        // If nanosleep failed or was interrupted by a signal,
+        // return so the caller can handle it appropriately
+        return -1;
+    } else if (flags == 0) {
+        return nanosleep(rqtp, rmtp);
+    } else {
+        // Invalid flags
+        errno = EINVAL;
+        return -1;
+    }
+
+    assert(0);
+    return -1;
+}
+
+#else
+# error clock_nanosleep not implemented on your platform!
+#endif
diff --git a/configure.ac b/configure.ac
index 134cae50a6..c20ab3c75c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -181,7 +181,9 @@ case "${host_os}" in
 
     dnl macOS 10.11 lacks clock_gettime, introduced with 10.12
     AC_LIBOBJ([clock_gettime])
-    AC_CHECK_FUNCS([clock_gettime])
+    dnl macOS lacks clock_nanosleep
+    AC_LIBOBJ([clock_nanosleep])
+    AC_CHECK_FUNCS([clock_gettime clock_nanosleep])
 
     AC_EGREP_CPP(yes,
             [#import <TargetConditionals.h>
diff --git a/include/vlc_fixups.h b/include/vlc_fixups.h
index 055bcf84d6..a296db0c32 100644
--- a/include/vlc_fixups.h
+++ b/include/vlc_fixups.h
@@ -660,6 +660,9 @@ FILE *vlc_win32_tmpfile(void);
 # define fdatasync fsync
 
 # include <time.h>
+# ifndef TIMER_ABSTIME
+#  define TIMER_ABSTIME 0x01
+# endif
 # ifndef CLOCK_REALTIME
 #  define CLOCK_REALTIME 0
 # endif
@@ -669,6 +672,10 @@ FILE *vlc_win32_tmpfile(void);
 # ifndef HAVE_CLOCK_GETTIME
 int clock_gettime(clockid_t clock_id, struct timespec *tp);
 # endif
+# ifndef HAVE_CLOCK_NANOSLEEP
+int clock_nanosleep(clockid_t clock_id, int flags,
+        const struct timespec *rqtp, struct timespec *rmtp);
+# endif
 #endif
 
 #ifdef __cplusplus
-- 
2.21.1 (Apple Git-122.3)