pjs/xpcom/ds/nsBufferHandle.h

182 строки
5.5 KiB
C++
Executable File

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is Mozilla strings.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
* Scott Collins <scc@mozilla.org> (original author)
*
*/
#ifndef nsBufferHandle_h___
#define nsBufferHandle_h___
#include <stddef.h>
// for |ptrdiff_t|
#include "prtypes.h"
// for |PRBool|
#include "nsDebug.h"
// for |NS_ASSERTION|
#include "nsMemory.h"
// for |nsMemory::Free|
/**
*
*/
template <class CharT>
class nsBufferHandle
{
public:
nsBufferHandle( CharT* aDataStart, CharT* aDataEnd ) : mDataStart(aDataStart), mDataEnd(aDataEnd) { }
void DataStart( CharT* aNewDataStart ) { mDataStart = aNewDataStart; }
CharT* DataStart() { return mDataStart; }
const CharT* DataStart() const { return mDataStart; }
void DataEnd( CharT* aNewDataEnd ) { mDataEnd = aNewDataEnd; }
CharT* DataEnd() { return mDataEnd; }
const CharT* DataEnd() const { return mDataEnd; }
// void DataLength( ptrdiff_t aNewDataLength ) { mDataEnd = mDataStart+aNewDataLength; }
ptrdiff_t DataLength() const { return mDataEnd - mDataStart; }
protected:
CharT* mDataStart;
CharT* mDataEnd;
};
/**
*
*/
template <class CharT>
class nsSharedBufferHandle
: public nsBufferHandle<CharT>
{
protected:
enum
{
kIsShared = 1<<31,
kIsSingleAllocationWithBuffer = 1<<30,
kIsStorageDefinedSeparately = 1<<29,
kFlagsMask = kIsShared | kIsSingleAllocationWithBuffer | kIsStorageDefinedSeparately,
kRefCountMask = ~kFlagsMask
};
public:
nsSharedBufferHandle( CharT* aDataStart, CharT* aDataEnd )
: nsBufferHandle<CharT>(aDataStart, aDataEnd)
{
mFlags |= kIsShared;
}
~nsSharedBufferHandle();
void
AcquireReference() const
{
nsSharedBufferHandle<CharT>* mutable_this = NS_CONST_CAST(nsSharedBufferHandle<CharT>*, this);
mutable_this->set_refcount( get_refcount()+1 );
}
void
ReleaseReference() const
{
nsSharedBufferHandle<CharT>* mutable_this = NS_CONST_CAST(nsSharedBufferHandle<CharT>*, this);
if ( !mutable_this->set_refcount( get_refcount()-1 ) )
delete mutable_this;
}
PRBool
IsReferenced() const
{
return get_refcount() != 0;
}
protected:
PRUint32 mFlags;
PRUint32
get_refcount() const
{
return mFlags & kRefCountMask;
}
PRUint32
set_refcount( PRUint32 aNewRefCount )
{
NS_ASSERTION(aNewRefCount <= kRefCountMask, "aNewRefCount <= kRefCountMask");
mFlags = (mFlags & kFlagsMask) | aNewRefCount;
return aNewRefCount;
}
};
// need a name for this
template <class CharT>
class nsFlexBufferHandle
: public nsSharedBufferHandle<CharT>
{
public:
nsFlexBufferHandle( CharT* aDataStart, CharT* aDataEnd, CharT* aStorageStart, CharT* aStorageEnd )
: nsSharedBufferHandle<CharT>(aDataStart, aDataEnd),
mStorageStart(aStorageStart),
mStorageEnd(aStorageEnd)
{
this->mFlags |= this->kIsStorageDefinedSeparately;
}
void StorageStart( CharT* aNewStorageStart ) { mStorageStart = aNewStorageStart; }
CharT* StorageStart() { return mStorageStart; }
const CharT* StorageStart() const { return mStorageStart; }
void StorageEnd( CharT* aNewStorageEnd ) { mStorageEnd = aNewStorageEnd; }
CharT* StorageEnd() { return mStorageEnd; }
const CharT* StorageEnd() const { return mStorageEnd; }
// void StorageLength( ptrdiff_t aNewStorageLength ) { mStorageEnd = mStorageStart+aNewStorageLength; }
ptrdiff_t StorageLength() const { return mStorageEnd - mStorageStart; }
protected:
CharT* mStorageStart;
CharT* mStorageEnd;
};
template <class CharT>
nsSharedBufferHandle<CharT>::~nsSharedBufferHandle()
// really don't want this to be |inline|
{
NS_ASSERTION(!IsReferenced(), "!IsReferenced()");
if ( !(mFlags & kIsSingleAllocationWithBuffer) )
{
CharT* string_storage = this->mDataStart;
if ( mFlags & kIsStorageDefinedSeparately )
string_storage = NS_REINTERPRET_CAST(nsFlexBufferHandle<CharT>*, this)->StorageStart();
nsMemory::Free(string_storage);
}
}
#endif // !defined(nsBufferHandle_h___)