Move many Thread related classes

beast/smart_ptr/SharedObject.h

@@ -0,0 +1,205 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of Beast: https://github.com/vinniefalco/Beast
+    Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
+
+    Portions of this file are from JUCE.
+    Copyright (c) 2013 - Raw Material Software Ltd.
+    Please visit http://www.juce.com
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef BEAST_SHAREDOBJECT_H_INCLUDED
+#define BEAST_SHAREDOBJECT_H_INCLUDED
+
+#include "../Config.h"
+#include "../Atomic.h"
+#include "../Uncopyable.h"
+
+namespace beast {
+
+//==============================================================================
+/**
+    Adds reference-counting to an object.
+
+    To add reference-counting to a class, derive it from this class, and
+    use the SharedPtr class to point to it.
+
+    e.g. @code
+    class MyClass : public SharedObject
+    {
+        void foo();
+
+        // This is a neat way of declaring a typedef for a pointer class,
+        // rather than typing out the full templated name each time..
+        typedef SharedPtr<MyClass> Ptr;
+    };
+
+    MyClass::Ptr p = new MyClass();
+    MyClass::Ptr p2 = p;
+    p = nullptr;
+    p2->foo();
+    @endcode
+
+    Once a new SharedObject has been assigned to a pointer, be
+    careful not to delete the object manually.
+
+    This class uses an Atomic<int> value to hold the reference count, so that it
+    the pointers can be passed between threads safely. For a faster but non-thread-safe
+    version, use SingleThreadedSharedObject instead.
+
+    @see SharedPtr, SharedObjectArray, SingleThreadedSharedObject
+*/
+class BEAST_API SharedObject : public Uncopyable
+{
+public:
+    //==============================================================================
+    /** Increments the object's reference count.
+
+        This is done automatically by the smart pointer, but is public just
+        in case it's needed for nefarious purposes.
+    */
+    inline void incReferenceCount() const noexcept
+    {
+        ++refCount;
+    }
+
+    /** Decreases the object's reference count.
+
+        If doDelete is true the object will be deleted when the reference
+        count drops to zero. The delete is performed using the regular
+        operator and does NOT go through the ContainerDeletePolicy.
+
+        The return value indicates if the reference count dropped to zero,
+        so callers who know the derived type can use the ContainerDeletePolicy.
+    */
+    void decReferenceCount () const
+    {
+        bassert (getReferenceCount() > 0);
+        if (--refCount == 0)
+            destroy ();
+    }
+
+    /** Returns the object's current reference count. */
+    inline int getReferenceCount() const noexcept
+    {
+        return refCount.get();
+    }
+
+protected:
+    //==============================================================================
+    /** Creates the reference-counted object (with an initial ref count of zero). */
+    SharedObject()
+    {
+    }
+
+    /** Destructor. */
+    virtual ~SharedObject()
+    {
+        // it's dangerous to delete an object that's still referenced by something else!
+        bassert (getReferenceCount() == 0);
+    }
+
+    /** Destroy the object.
+        Derived classes can override this for different behaviors.
+    */
+    virtual void destroy () const
+    {
+        delete this;
+    }
+
+    /** Resets the reference count to zero without deleting the object.
+        You should probably never need to use this!
+    */
+    void resetReferenceCount() noexcept
+    {
+        refCount = 0;
+    }
+
+private:
+    //==============================================================================
+    Atomic <int> mutable refCount;
+};
+
+//==============================================================================
+/**
+    Adds reference-counting to an object.
+
+    This is effectively a version of the SharedObject class, but which
+    uses a non-atomic counter, and so is not thread-safe (but which will be more
+    efficient).
+    For more details on how to use it, see the SharedObject class notes.
+
+    @see SharedObject, SharedPtr, SharedObjectArray
+*/
+class BEAST_API SingleThreadedSharedObject : public Uncopyable
+{
+public:
+    //==============================================================================
+    /** Increments the object's reference count.
+
+        This is done automatically by the smart pointer, but is public just
+        in case it's needed for nefarious purposes.
+    */
+    inline void incReferenceCount() noexcept
+    {
+        ++refCount;
+    }
+
+    /** Decreases the object's reference count.
+
+        If doDelete is true the object will be deleted when the reference
+        count drops to zero. The delete is performed using the regular
+        operator and does NOT go through the ContainerDeletePolicy.
+
+        The return value indicates if the reference count dropped to zero,
+        so callers who know the derived type can use the ContainerDeletePolicy.
+    */
+    inline void decReferenceCount ()
+    {
+        bassert (getReferenceCount() > 0);
+        if (--refCount == 0)
+            destroy ();
+    }
+
+    /** Returns the object's current reference count. */
+    inline int getReferenceCount() const noexcept       { return refCount; }
+
+
+protected:
+    //==============================================================================
+    /** Creates the reference-counted object (with an initial ref count of zero). */
+    SingleThreadedSharedObject() : refCount (0)  {}
+
+    /** Destructor. */
+    virtual ~SingleThreadedSharedObject()
+    {
+        // it's dangerous to delete an object that's still referenced by something else!
+        bassert (getReferenceCount() == 0);
+    }
+
+    virtual void destroy () const
+    {
+        delete this;
+    }
+
+private:
+    //==============================================================================
+    int refCount;
+};
+
+}
+
+#endif