From fb7bb2ee352cf83a7596a7ed7ba2913a2257e540 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Wed, 13 Apr 2016 18:30:56 +0200
Subject: New Semaphore method wait with timeout.

---
 drumgizmo/output/jackaudio.cc |  1 -
 src/drumkitloader.cc          |  3 +-
 src/semaphore.cc              | 96 +++++++++++++++++++++++++------------------
 src/semaphore.h               | 24 ++++++-----
 4 files changed, 70 insertions(+), 54 deletions(-)

diff --git a/drumgizmo/output/jackaudio.cc b/drumgizmo/output/jackaudio.cc
index 7710e14..abd7d4f 100644
--- a/drumgizmo/output/jackaudio.cc
+++ b/drumgizmo/output/jackaudio.cc
@@ -33,7 +33,6 @@ JackAudioOutputEngine::JackAudioOutputEngine(JackClient& client)
 	: AudioOutputEngine{}
 	, client(client)
 	, channels{}
-	, sema{"jackaudio"}
 {
 	client.add(*this);
 }
diff --git a/src/drumkitloader.cc b/src/drumkitloader.cc
index f9e45db..d785bc4 100644
--- a/src/drumkitloader.cc
+++ b/src/drumkitloader.cc
@@ -32,8 +32,7 @@
 #include "drumgizmo.h"
 
 DrumKitLoader::DrumKitLoader(Settings& settings)
-	: semaphore("drumkitloader")
-	, framesize(0)
+	: framesize(0)
 	, settings(settings)
 {
 	run();
diff --git a/src/semaphore.cc b/src/semaphore.cc
index cd29bbf..3a4f6c9 100644
--- a/src/semaphore.cc
+++ b/src/semaphore.cc
@@ -27,87 +27,101 @@
 #include "semaphore.h"
 
 #include <hugin.hpp>
-
 #include <limits>
+#include <assert.h>
 
 #ifdef WIN32
 #include <windows.h>
 #else
-// Make sure we don't include /this/ file...
+// Make sure we don't include /this/ files header...
 #include <../include/semaphore.h>
+#include <errno.h>
+#include <stdio.h>
 #endif
 
 struct semaphore_private_t {
 #ifdef WIN32
-  HANDLE semaphore; 
+	HANDLE semaphore;
 #else
-  sem_t semaphore;
+	sem_t semaphore;
 #endif
 };
 
-Semaphore::Semaphore(const char *name)
+Semaphore::Semaphore(std::size_t initial_count)
 {
-  this->name = name;
-  //  DEBUG(semaphore, "Create [%s]\n", name);
-
-  prv = new struct semaphore_private_t();
+	prv = new struct semaphore_private_t();
 
 #ifdef WIN32
-  prv->semaphore = CreateSemaphore(NULL,  // default security attributes
-                                   0, // initial count
-                                   std::numeric_limits<LONG>::max(),
-                                   NULL); // unnamed semaphore
+	prv->semaphore = CreateSemaphore(nullptr,  // default security attributes
+	                                 initial_count,
+	                                 std::numeric_limits<LONG>::max(),
+	                                 nullptr); // unnamed semaphore
 #else
-  sem_init(&prv->semaphore, 0, 0);
+	const int pshared = 0;
+	sem_init(&prv->semaphore, pshared, initial_count);
 #endif
 }
 
 Semaphore::~Semaphore()
 {
-  //  DEBUG(semaphore, "Delete [%s]\n", name);
-
 #ifdef WIN32
-  CloseHandle(prv->semaphore);
+	CloseHandle(prv->semaphore);
 #else
-  sem_destroy(&prv->semaphore);
+	sem_destroy(&prv->semaphore);
 #endif
 
-  delete prv;
+	delete prv;
 }
 
 void Semaphore::post()
 {
-  //  DEBUG(semaphore, "Post [%s]\n", name);
+#ifdef WIN32
+	ReleaseSemaphore(prv->semaphore, 1, NULL);
+#else
+	sem_post(&prv->semaphore);
+#endif
+}
 
+bool Semaphore::wait(const std::chrono::milliseconds& timeout)
+{
 #ifdef WIN32
-  ReleaseSemaphore(prv->semaphore, 1, NULL);
+	DWORD ret = WaitForSingleObject(prv->semaphore, timeout.count());
+	if(ret == WAIT_TIMEOUT)
+	{
+		return false;
+	}
+
+	assert(ret == WAIT_OBJECT_0);
 #else
-  sem_post(&prv->semaphore);
+	struct timespec t = {
+		// Whole seconds:
+		(time_t)(timeout.count() % 1000),
+
+		// Remainder as nanoseconds:
+		(long)((timeout.count() - (t.tv_sec * timeout.count())) * 1000000)
+	};
+
+	int ret = sem_timedwait(&prv->semaphore, &t);
+	if(ret < 0)
+	{
+		if(errno == ETIMEDOUT)
+		{
+			return false;
+		}
+
+		perror("sem_timedwait()");
+		assert(false);
+	}
 #endif
+
+	return true;
 }
 
 void Semaphore::wait()
 {
-  //  DEBUG(semaphore, "Wait [%s]\n", name);
-
 #ifdef WIN32
-  WaitForSingleObject(prv->semaphore, INFINITE);
+	WaitForSingleObject(prv->semaphore, INFINITE);
 #else
-  sem_wait(&prv->semaphore);
+	sem_wait(&prv->semaphore);
 #endif
 }
-
-#ifdef TEST_SEMAPHORE
-//deps:
-//cflags: -I.. $(PTHREAD_CFLAGS)
-//libs: $(PTHREAD_LIBS)
-#include <test.h>
-
-TEST_BEGIN;
-
-// TODO: Put some testcode here (see test.h for usable macros).
-TEST_TRUE(false, "No tests yet!");
-
-TEST_END;
-
-#endif/*TEST_SEMAPHORE*/
diff --git a/src/semaphore.h b/src/semaphore.h
index 4464898..d5995cb 100644
--- a/src/semaphore.h
+++ b/src/semaphore.h
@@ -24,22 +24,26 @@
  *  along with DrumGizmo; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
  */
-#ifndef __PRACRO_SEMAPHORE_H__
-#define __PRACRO_SEMAPHORE_H__
+#pragma once
+
+#include <chrono>
 
 struct semaphore_private_t;
 
-class Semaphore {
+class Semaphore
+{
 public:
-  Semaphore(const char *name = "");
-  ~Semaphore();
+	Semaphore(std::size_t initial_count = 0);
+	~Semaphore();
+
+	void post();
 
-  void post();
-  void wait();
+	//! Lock semaphore with timeout.
+	//! \returns true if the semaphore was locked, false on timeout.
+	bool wait(const std::chrono::milliseconds& timeout);
+
+	void wait();
 
 private:
 	struct semaphore_private_t *prv{nullptr};
-	const char *name{nullptr};
 };
-
-#endif/*__PRACRO_SEMAPHORE_H__*/
-- 
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