rippled/beast/module/core/native/win32_ComSmartPtr.h

//------------------------------------------------------------------------------
/*
    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_WIN32_COMSMARTPTR_H_INCLUDED
#define BEAST_WIN32_COMSMARTPTR_H_INCLUDED

namespace beast
{

#ifndef _MSC_VER
template<typename Type> struct UUIDGetter { static CLSID get() { bassertfalse; return CLSID(); } };
#define __uuidof(x)  UUIDGetter<x>::get()
#endif

inline GUID uuidFromString (const char* const s) noexcept
{
    unsigned long p0;
    unsigned int p1, p2, p3, p4, p5, p6, p7, p8, p9, p10;

  #ifndef _MSC_VER
    sscanf
  #else
    sscanf_s
  #endif
        (s, "%08lX-%04X-%04X-%02X%02X-%02X%02X%02X%02X%02X%02X",
              &p0, &p1, &p2, &p3, &p4, &p5, &p6, &p7, &p8, &p9, &p10);

    GUID g = { p0, (std::uint16_t) p1, (std::uint16_t) p2, { (std::uint8_t) p3, (std::uint8_t) p4, (std::uint8_t) p5, (std::uint8_t) p6,
                                               (std::uint8_t) p7, (std::uint8_t) p8, (std::uint8_t) p9, (std::uint8_t) p10 }};
    return g;
}

//==============================================================================
/** A simple COM smart pointer.
*/
template <class ComClass>
class ComSmartPtr
{
public:
    ComSmartPtr() throw() : p (0)                                  {}
    ComSmartPtr (ComClass* const obj) : p (obj)                    { if (p) p->AddRef(); }
    ComSmartPtr (const ComSmartPtr<ComClass>& other) : p (other.p) { if (p) p->AddRef(); }
    ~ComSmartPtr()                                                 { release(); }

    operator ComClass*() const throw()     { return p; }
    ComClass& operator*() const throw()    { return *p; }
    ComClass* operator->() const throw()   { return p; }

    ComSmartPtr& operator= (ComClass* const newP)
    {
        if (newP != 0)  newP->AddRef();
        release();
        p = newP;
        return *this;
    }

    ComSmartPtr& operator= (const ComSmartPtr<ComClass>& newP)  { return operator= (newP.p); }

    // Releases and nullifies this pointer and returns its address
    ComClass** resetAndGetPointerAddress()
    {
        release();
        p = 0;
        return &p;
    }

    HRESULT CoCreateInstance (REFCLSID classUUID, DWORD dwClsContext = CLSCTX_INPROC_SERVER)
    {
        HRESULT hr = ::CoCreateInstance (classUUID, 0, dwClsContext, __uuidof (ComClass), (void**) resetAndGetPointerAddress());
        bassert (hr != CO_E_NOTINITIALIZED); // You haven't called CoInitialize for the current thread!
        return hr;
    }

    template <class OtherComClass>
    HRESULT QueryInterface (REFCLSID classUUID, ComSmartPtr<OtherComClass>& destObject) const
    {
        if (p == 0)
            return E_POINTER;

        return p->QueryInterface (classUUID, (void**) destObject.resetAndGetPointerAddress());
    }

    template <class OtherComClass>
    HRESULT QueryInterface (ComSmartPtr<OtherComClass>& destObject) const
    {
        return this->QueryInterface (__uuidof (OtherComClass), destObject);
    }

private:
    ComClass* p;

    void release()  { if (p != 0) p->Release(); }

    ComClass** operator&() throw(); // private to avoid it being used accidentally
};

//==============================================================================
#define BEAST_COMRESULT  HRESULT __stdcall

//==============================================================================
template <class ComClass>
class ComBaseClassHelperBase   : public ComClass
{
public:
    ComBaseClassHelperBase (unsigned int initialRefCount)  : refCount (initialRefCount) {}
    virtual ~ComBaseClassHelperBase() {}

    ULONG __stdcall AddRef()    { return ++refCount; }
    ULONG __stdcall Release()   { const ULONG r = --refCount; if (r == 0) delete this; return r; }

protected:
    ULONG refCount;

    BEAST_COMRESULT QueryInterface (REFIID refId, void** result)
    {
        if (refId == IID_IUnknown)
            return castToType <IUnknown> (result);

        *result = 0;
        return E_NOINTERFACE;
    }

    template <class Type>
    BEAST_COMRESULT castToType (void** result)
    {
        this->AddRef(); *result = dynamic_cast <Type*> (this); return S_OK;
    }
};

/** Handy base class for writing COM objects, providing ref-counting and a basic QueryInterface method.
*/
template <class ComClass>
class ComBaseClassHelper   : public ComBaseClassHelperBase <ComClass>
{
public:
    ComBaseClassHelper (unsigned int initialRefCount = 1) : ComBaseClassHelperBase <ComClass> (initialRefCount) {}
    ~ComBaseClassHelper() {}

    BEAST_COMRESULT QueryInterface (REFIID refId, void** result)
    {
        if (refId == __uuidof (ComClass))
            return this->template castToType <ComClass> (result);

        return ComBaseClassHelperBase <ComClass>::QueryInterface (refId, result);
    }
};

} // beast

#endif   // BEAST_WIN32_COMSMARTPTR_H_INCLUDED