1 files changed, 68 insertions, 0 deletions
diff --git a/libs/pbd/glib_semaphore.cc b/libs/pbd/glib_semaphore.cc
new file mode 100644
index 0000000000..7565e0c069
--- /dev/null
+++ b/libs/pbd/glib_semaphore.cc
@@ -0,0 +1,68 @@
+/*
+    Copyright (C) 2010 Tim Mayberry
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include "pbd/glib_semaphore.h"
+
+namespace PBD {
+
+GlibSemaphore::GlibSemaphore (gint initial_val)
+	:
+		m_counter(initial_val)
+{ }
+
+void
+GlibSemaphore::wait ()
+{
+	Glib::Threads::Mutex::Lock guard (m_mutex);
+
+	while (m_counter.get() < 1) {
+		m_cond.wait(m_mutex);
+	}
+
+	// this shouldn't need to be inside the lock
+	--m_counter;
+}
+
+bool
+GlibSemaphore::try_wait ()
+{
+	if (!m_mutex.trylock())
+	{
+		return false;
+	}
+	// lock successful
+	while (m_counter.get() < 1) {
+		m_cond.wait(m_mutex);
+	}
+
+	// the order of these should not matter
+	--m_counter;
+	m_mutex.unlock();
+	return true;
+}
+
+void
+GlibSemaphore::post ()
+{
+	// atomic, no locking required
+	++m_counter;
+	m_cond.signal();
+}
+
+} // namespace PBD