Add beast_basics module

modules/beast_basics/threads/beast_ConcurrentObject.h

@@ -0,0 +1,92 @@
+/*============================================================================*/
+/*
+  VFLib: https://github.com/vinniefalco/VFLib
+
+  Copyright (C) 2008 by Vinnie Falco <vinnie.falco@gmail.com>
+
+  This library contains portions of other open source products covered by
+  separate licenses. Please see the corresponding source files for specific
+  terms.
+
+  VFLib is provided under the terms of The MIT License (MIT):
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+  IN THE SOFTWARE.
+*/
+/*============================================================================*/
+
+#ifndef BEAST_CONCURRENTOBJECT_BEASTHEADER
+#define BEAST_CONCURRENTOBJECT_BEASTHEADER
+
+/*============================================================================*/
+/**
+  A reference counted object with overridable destroy behavior.
+
+  This is a reference counted object compatible with
+  ReferenceCountedObjectPtr. When the last reference is removed, the
+  object is queued for deletion on a separate, provided thread. On
+  program exit the thread will clean itself up - no other action is
+  required.
+
+  This class is useful for offloading the deletion work of "deep" objects
+  shared by multiple threads: objects containing complex members, or a
+  hierarchy of allocated structures. For example, a ValueTree. The problem
+  of performing heavyweight memory or cleanup operations from either an
+  AudioIODeviceCallback or the message thread is avoided.
+
+  The deletion behavior can be overriden by providing a replacement
+  for destroyConcurrentObject().
+
+  @ingroup beast_concurrent
+*/
+class ConcurrentObject : Uncopyable
+{
+public:
+    inline void incReferenceCount () noexcept
+    {
+        m_refs.addref ();
+    }
+
+    inline void decReferenceCount () noexcept
+    {
+        if (m_refs.release ())
+            destroyConcurrentObject ();
+    }
+
+protected:
+    ConcurrentObject ();
+
+    virtual ~ConcurrentObject ();
+
+    /** Delete the object.
+
+        This function is called when the reference count drops to zero. The
+        default implementation performs the delete on a separate, provided thread
+        that cleans up after itself on exit.
+    */
+    virtual void destroyConcurrentObject ();
+
+protected:
+    class Deleter;
+
+private:
+    AtomicCounter m_refs;
+};
+
+#endif
+