From 767fcceaeb456f5e281a6bd1b3f51713e4989293 Mon Sep 17 00:00:00 2001
From: Nikias Bassen
Date: Fri, 11 Oct 2019 23:08:48 +0200
Subject: Use condition variable instead of active waiting for device event
 handling

With some devices and USB hardware the reconnect of a device might actually
be faster than the check interval of the active waiting loop. With mutexes
and a condition variable we will not miss the moment of reconnect anymore,
even if it is really quick (like 7ms, right DanyL?)
---
 src/thread.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

(limited to 'src/thread.c')

diff --git a/src/thread.c b/src/thread.c
index b84ee66..8ccdd7f 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -115,3 +115,63 @@ void thread_once(thread_once_t *once_control, void (*init_routine)(void))
 	pthread_once(once_control, init_routine);
 #endif
 }
+
+void cond_init(cond_t* cond)
+{
+#ifdef WIN32
+	cond->sem = CreateSemaphore(NULL, 0, 32767, NULL);
+#else
+	pthread_cond_init(cond, NULL);
+#endif
+}
+
+void cond_destroy(cond_t* cond)
+{
+#ifdef WIN32
+	CloseHandle(cond->sem);
+#else
+	pthread_cond_destroy(cond);
+#endif
+}
+
+int cond_signal(cond_t* cond)
+{
+#ifdef WIN32
+	int result = 0;
+	if (!ReleaseSemaphore(cond->sem, 1, NULL)) {
+		result = -1;
+	}
+	return result;
+#else
+	return pthread_cond_signal(cond);
+#endif
+}
+
+int cond_wait(cond_t* cond, mutex_t* mutex)
+{
+#ifdef WIN32
+	mutex_unlock(mutex);
+	WaitForSingleObject(cond->sem, INFINITE);
+#else
+	return pthread_cond_wait(cond, mutex);
+#endif
+}
+
+int cond_wait_timeout(cond_t* cond, mutex_t* mutex, unsigned int timeout_ms)
+{
+#ifdef WIN32
+	mutex_unlock(mutex);
+	WaitForSingleObject(cond->sem, timeout_ms);
+#else
+	struct timespec ts;
+	struct timeval now;
+	gettimeofday(&now, NULL);
+
+	ts.tv_sec = now.tv_sec + timeout_ms / 1000;
+	ts.tv_nsec = now.tv_usec * 1000 + 1000 * 1000 * (timeout_ms % 1000);
+	ts.tv_sec += ts.tv_nsec / (1000 * 1000 * 1000);
+	ts.tv_nsec %= (1000 * 1000 * 1000);
+
+	return pthread_cond_timedwait(cond, mutex, &ts);
+#endif
+}
-- 
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