1 files changed, 77 insertions, 0 deletions
diff --git a/src/port/pthread_barrier_wait.c b/src/port/pthread_barrier_wait.c
new file mode 100644
index 0000000..9e59b3f
--- /dev/null
+++ b/src/port/pthread_barrier_wait.c
@@ -0,0 +1,77 @@
+/*-------------------------------------------------------------------------
+ *
+ * pthread_barrier_wait.c
+ *    Implementation of pthread_barrier_t support for platforms lacking it.
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *    src/port/pthread_barrier_wait.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "c.h"
+
+#include "port/pg_pthread.h"
+
+int
+pthread_barrier_init(pthread_barrier_t *barrier, const void *attr, int count)
+{
+	int			error;
+
+	barrier->sense = false;
+	barrier->count = count;
+	barrier->arrived = 0;
+	if ((error = pthread_cond_init(&barrier->cond, NULL)) != 0)
+		return error;
+	if ((error = pthread_mutex_init(&barrier->mutex, NULL)) != 0)
+	{
+		pthread_cond_destroy(&barrier->cond);
+		return error;
+	}
+
+	return 0;
+}
+
+int
+pthread_barrier_wait(pthread_barrier_t *barrier)
+{
+	bool		initial_sense;
+
+	pthread_mutex_lock(&barrier->mutex);
+
+	/* We have arrived at the barrier. */
+	barrier->arrived++;
+	Assert(barrier->arrived <= barrier->count);
+
+	/* If we were the last to arrive, release the others and return. */
+	if (barrier->arrived == barrier->count)
+	{
+		barrier->arrived = 0;
+		barrier->sense = !barrier->sense;
+		pthread_mutex_unlock(&barrier->mutex);
+		pthread_cond_broadcast(&barrier->cond);
+
+		return PTHREAD_BARRIER_SERIAL_THREAD;
+	}
+
+	/* Wait for someone else to flip the sense. */
+	initial_sense = barrier->sense;
+	do
+	{
+		pthread_cond_wait(&barrier->cond, &barrier->mutex);
+	} while (barrier->sense == initial_sense);
+
+	pthread_mutex_unlock(&barrier->mutex);
+
+	return 0;
+}
+
+int
+pthread_barrier_destroy(pthread_barrier_t *barrier)
+{
+	pthread_cond_destroy(&barrier->cond);
+	pthread_mutex_destroy(&barrier->mutex);
+	return 0;
+}