From e70db68fac1adbb5c9823231aa800658c4d7cc12 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Thu, 11 Jul 2013 12:46:05 -0400
Subject: [PATCH] Add implementation for ProcessSemaphore on windows

---
 libs/pbd/pbd/semutils.h | 16 +++++++++++++++-
 libs/pbd/semutils.cc    | 30 ++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/libs/pbd/pbd/semutils.h b/libs/pbd/pbd/semutils.h
index 6f5f0e9331..0e8bed0512 100644
--- a/libs/pbd/pbd/semutils.h
+++ b/libs/pbd/pbd/semutils.h
@@ -19,13 +19,20 @@
 #ifndef __pbd_semutils_h__
 #define __pbd_semutils_h__
 
+#ifdef WIN32
+#include <windows.h>
+#else
 #include <semaphore.h>
+#endif
 
 namespace PBD {
 
 class ProcessSemaphore {
   private:
-#ifdef __APPLE__
+#ifdef WIN32
+	HANDLE _sem;
+
+#elif __APPLE__
 	sem_t* _sem;
 	sem_t* ptr_to_sem() const { return _sem; }
 #else
@@ -37,8 +44,15 @@ class ProcessSemaphore {
 	ProcessSemaphore (const char* name, int val);
 	~ProcessSemaphore ();
 
+#ifdef WIN32
+
+	int signal ();
+	int wait ();
+
+#else
 	int signal () { return sem_post (ptr_to_sem()); }
 	int wait () { return sem_wait (ptr_to_sem()); }
+#endif
 };
 
 }
diff --git a/libs/pbd/semutils.cc b/libs/pbd/semutils.cc
index 9ac5f60d35..e5df2e5c44 100644
--- a/libs/pbd/semutils.cc
+++ b/libs/pbd/semutils.cc
@@ -23,7 +23,12 @@ using namespace PBD;
 
 ProcessSemaphore::ProcessSemaphore (const char* name, int val)
 {
-#ifdef __APPLE__
+#ifdef WIN32
+	if ((_sem = CreateSemaphore(NULL, val, 32767, name)) == NULL) {
+		throw failed_constructor ();
+	}
+
+#elif __APPLE__
 	if ((_sem = sem_open (name, O_CREAT, 0600, val)) == (sem_t*) SEM_FAILED) {
 		throw failed_constructor ();
 	}
@@ -43,7 +48,28 @@ ProcessSemaphore::ProcessSemaphore (const char* name, int val)
 
 ProcessSemaphore::~ProcessSemaphore ()
 {
-#ifdef __APPLE__
+#ifdef WIN32
+	CloseHandle(_sem);
+#elif __APPLE__
 	sem_close (ptr_to_sem());
 #endif
 }
+
+#ifdef WIN32
+
+int
+ProcessSemaphore::signal ()
+{
+	// non-zero on success, opposite to posix
+	return !ReleaseSemaphore(_sem, 1, NULL);
+}
+
+int
+ProcessSemaphore::wait ()
+{
+	DWORD result = 0;
+	result = WaitForSingleObject(_sem, INFINITE);
+	return (result == WAIT_OBJECT_0);
+}
+
+#endif