import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

media/libcubeb/src/cubeb_utils_win.h

@@ -0,0 +1,71 @@
+/*
+ * Copyright © 2016 Mozilla Foundation
+ *
+ * This program is made available under an ISC-style license.  See the
+ * accompanying file LICENSE for details.
+ */
+
+#if !defined(CUBEB_UTILS_WIN)
+#define CUBEB_UTILS_WIN
+
+#include <windows.h>
+#include "cubeb-internal.h"
+
+/* This wraps a critical section to track the owner in debug mode, adapted from
+   NSPR and http://blogs.msdn.com/b/oldnewthing/archive/2013/07/12/10433554.aspx */
+class owned_critical_section
+{
+public:
+  owned_critical_section()
+#ifndef NDEBUG
+    : owner(0)
+#endif
+  {
+    InitializeCriticalSection(&critical_section);
+  }
+
+  ~owned_critical_section()
+  {
+    DeleteCriticalSection(&critical_section);
+  }
+
+  void enter()
+  {
+    EnterCriticalSection(&critical_section);
+#ifndef NDEBUG
+    XASSERT(owner != GetCurrentThreadId() && "recursive locking");
+    owner = GetCurrentThreadId();
+#endif
+  }
+
+  void leave()
+  {
+#ifndef NDEBUG
+    /* GetCurrentThreadId cannot return 0: it is not a the valid thread id */
+    owner = 0;
+#endif
+    LeaveCriticalSection(&critical_section);
+  }
+
+  /* This is guaranteed to have the good behaviour if it succeeds. The behaviour
+     is undefined otherwise. */
+  void assert_current_thread_owns()
+  {
+#ifndef NDEBUG
+    /* This implies owner != 0, because GetCurrentThreadId cannot return 0. */
+    XASSERT(owner == GetCurrentThreadId());
+#endif
+  }
+
+private:
+  CRITICAL_SECTION critical_section;
+#ifndef NDEBUG
+  DWORD owner;
+#endif
+
+  // Disallow copy and assignment because CRICICAL_SECTION cannot be copied.
+  owned_critical_section(const owned_critical_section&);
+  owned_critical_section& operator=(const owned_critical_section&);
+};
+
+#endif /* CUBEB_UTILS_WIN */