thread/{Mutex,Cond}: new backend for WIN32

Use CRITICAL_SECTION and CONDITION_VARIABLE.  This requires Windows
Vista or newer.  It fixes problems with GLib threading objects that
were implicitly created by static constructors before g_thread_init().

src/thread/CriticalSection.hxx

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2009-2013 Max Kellermann <max@duempel.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef MPD_THREAD_CRITICAL_SECTION_HXX
+#define MPD_THREAD_CRITICAL_SECTION_HXX
+
+#include <windows.h>
+
+/**
+ * Wrapper for a CRITICAL_SECTION, backend for the Mutex class.
+ */
+class CriticalSection {
+	friend class WindowsCond;
+
+	CRITICAL_SECTION critical_section;
+
+public:
+	CriticalSection() {
+		::InitializeCriticalSection(&critical_section);
+	}
+
+	~CriticalSection() {
+		::DeleteCriticalSection(&critical_section);
+	}
+
+	CriticalSection(const CriticalSection &other) = delete;
+	CriticalSection &operator=(const CriticalSection &other) = delete;
+
+	void lock() {
+		::EnterCriticalSection(&critical_section);
+	};
+
+	bool try_lock() {
+		return ::TryEnterCriticalSection(&critical_section) != 0;
+	};
+
+	void unlock() {
+		::LeaveCriticalSection(&critical_section);
+	}
+};
+
+#endif