domstring.cpp

来自「IBM的解析xml的工具Xerces的源代码」· C++ 代码 · 共 1,182 行 · 第 1/3 页

/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * $Id: DOMString.cpp,v 1.11 2004/09/28 10:56:04 amassari Exp $
 */

#include <stdio.h>
#include <xercesc/util/PlatformUtils.hpp>
#include <xercesc/util/RuntimeException.hpp>
#include <xercesc/util/TransService.hpp>
#include <xercesc/util/XMLString.hpp>
#include <xercesc/util/XMLRegisterCleanup.hpp>
#include "DOM_DOMException.hpp"
#include "DOMString.hpp"

#ifndef XML_DEBUG
#include "DOMStringImpl.hpp"
#endif

#include <assert.h>
#include <string.h>

XERCES_CPP_NAMESPACE_BEGIN

//----------------------------------------------
//
//  Forward decls
//
//----------------------------------------------
static void reinitDomConverter();
static void reinitDomMutex();
XMLLCPTranscoder*  getDomConverter();


// ---------------------------------------------------------------------------
//  Local static functions
// ---------------------------------------------------------------------------

//  getDOMConverter - get the converter from the system default
//          codepage to Unicode that is to be used when
//          a DOMString is constructed from a char *.
//
static XMLLCPTranscoder* gDomConverter = 0;
static XMLRegisterCleanup cleanupDomConverter;

int DOMString::gLiveStringDataCount    = 0;
int DOMString::gTotalStringDataCount   = 0;
int DOMString::gLiveStringHandleCount  = 0;
int DOMString::gTotalStringHandleCount = 0;


XMLLCPTranscoder*  getDomConverter()
{
    if (!gDomConverter)
    {
        XMLLCPTranscoder* transcoder = XMLPlatformUtils::fgTransService->makeNewLCPTranscoder();
        if (!transcoder)
            XMLPlatformUtils::panic(PanicHandler::Panic_NoDefTranscoder
            );

        if (XMLPlatformUtils::compareAndSwap((void **)&gDomConverter, transcoder, 0) != 0)
            delete transcoder;
        else
            cleanupDomConverter.registerCleanup(reinitDomConverter);
    }
    return gDomConverter;
};

//
//  There is one global mutex that is used to synchronize access to the
//     allocator free list for DOMStringHandles.  This function gets that
//     mutex, and will create it on the first attempt to get it.
//
static XMLMutex* DOMStringHandleMutex = 0;   // Mutex will be deleted by ~DOMStringHandle.
static XMLRegisterCleanup cleanupDomMutex;

XMLMutex& DOMStringHandle::getMutex()
{
    if (!DOMStringHandleMutex)
    {
        XMLMutex* tmpMutex = new XMLMutex;
        if (XMLPlatformUtils::compareAndSwap((void**)&DOMStringHandleMutex, tmpMutex, 0))
        {
            // Someone beat us to it, so let's clean up ours
            delete tmpMutex;
        }
        else
            cleanupDomMutex.registerCleanup(reinitDomMutex);

    }

    return *DOMStringHandleMutex;
}



//----------------------------------------------
//
//      DOMStringData
//
//----------------------------------------------

void DOMStringData::removeRef()
{
    int result = XMLPlatformUtils::atomicDecrement(fRefCount);
    if (result==0)
    {
        fBufferLength = 0xcccc;
        fRefCount     = 0xcccc;
        XMLPlatformUtils::fgMemoryManager->deallocate(this);//delete [] this;  //  was allocated with new char[size] !
        XMLPlatformUtils::atomicDecrement(DOMString::gLiveStringDataCount);
    };
};


void DOMStringData::addRef()
{
    XMLPlatformUtils::atomicIncrement(fRefCount);
};


DOMStringData *DOMStringData::allocateBuffer(unsigned int length)
{
    unsigned int sizeToAllocate = sizeof(DOMStringData) //  buffer will contain an
        + length*sizeof(XMLCh);                //  extra elem because of stub
                                               //  array in DOMStringData struct.
    DOMStringData *buf = 0;
    buf = (DOMStringData *) XMLPlatformUtils::fgMemoryManager->allocate
        (
            sizeToAllocate * sizeof(char)
        );//new char[sizeToAllocate];
    XMLPlatformUtils::atomicIncrement(DOMString::gLiveStringDataCount);
    XMLPlatformUtils::atomicIncrement(DOMString::gTotalStringDataCount);
    buf->fBufferLength = length;
    buf->fRefCount = 1;
    buf->fData[0] = 0;
    return buf;
}




//----------------------------------------------------
//
//      DOMStringHandle
//
//-----------------------------------------------------



//
//  Specialized new and delete operators for DOMStringHandles.
//      These are used, rather than the standard system operator new,
//      for improved performance.
//
//      We allocate largish blocks of memory using the standard system
//      new function, and sub-allocate string handles from that block.
//      Un-allocated string handles within the allocated blocks are kept
//      in a singly linked list, making allocation and deallocation
//      very quick in the common case.
//
//      String handle allocation is thread safe.  A multi-threaded
//      application may have threads concurrently accessing multiple
//      DOM documents; since all string handles come from the same pool,
//      this allocator must be safe.  The compare and exchange function,
//      which is available as a single instruction in most processor
//      architectures, and typically surfaced as an OS function,
//      is used to safely update the string handle free list.
//
void *DOMStringHandle::freeListPtr = 0;   // Point to the head of the
                                          //  free list of un-allocated
                                          //  string handles, or 0 if there
                                          //  are no free string handles.

static const int allocGroupSize = 1024;   // Number of string handles to allocate
                                          //  as a chunk from the system's
                                          //  memory allocator.

DOMStringHandle *DOMStringHandle::blockListPtr = 0;  // Point to the head of the list
                                          //  of larger blocks in which DOMStringHandles
                                          //  are allocated.

//
//  Operator new for DOMStringHandles.  Called implicitly from the
//          DOMStringHandle constructor.
//
void *DOMStringHandle::operator new(size_t sizeToAlloc)
{
    assert(sizeToAlloc == sizeof(DOMStringHandle));
    void    *retPtr;
    XMLMutexLock lock(&getMutex());    // Lock the DOMStringHandle mutex for
                                       //  the duration of this function.

    if (freeListPtr == 0)
    {
        // Uncommon case.  The free list of string handles is empty
        // Allocate a new batch of them, using the system's
        // operator new to get a chunk of memory.
        //
        DOMStringHandle *dsg = (DOMStringHandle*)
            XMLPlatformUtils::fgMemoryManager->allocate
            (
                allocGroupSize * sizeof(DOMStringHandle)
            );//::new DOMStringHandle[allocGroupSize];

        // Link the block itself into the list of blocks.  The purpose of this is to
        //   let us locate and delete the blocks when shutting down.
        //
        *(DOMStringHandle **)dsg = blockListPtr;
        blockListPtr = dsg;


        // Link all of the new storage for StringHandles into the StringHandle free list
        int   i;    //   Start with index 1;  index 0 is reserved for linking the
                    //   larger allocation blocks together.
        for (i=1; i<allocGroupSize-1; i++) {
            *(void **)&dsg[i] = freeListPtr;
            freeListPtr = &dsg[i];
        }
    }

    retPtr = freeListPtr;
    freeListPtr = *(void **)freeListPtr;

    XMLPlatformUtils::atomicIncrement(DOMString::gLiveStringHandleCount);
    return retPtr;
};


//
//  Operator delete for DOMStringHandles.  Called implicitly from the
//              Destructor for DOMStringHandle.
//
void DOMStringHandle::operator delete(void *pMem)
{
    XMLMutexLock   lock(&getMutex());    // Lock the DOMStringHandle mutex for the
    //    duration of this function.
    XMLPlatformUtils::atomicDecrement(DOMString::gLiveStringHandleCount);
    *(void **)pMem = freeListPtr;
    freeListPtr = pMem;

    // If ALL of the string handles are gone, delete the storage blocks used for the
    //   handles as well.
    if (DOMString::gLiveStringHandleCount == 0)
    {
        DOMStringHandle *pThisBlock, *pNextBlock;
        for (pThisBlock = blockListPtr; pThisBlock != 0; pThisBlock = pNextBlock)
        {
            pNextBlock = *(DOMStringHandle **)pThisBlock;
            XMLPlatformUtils::fgMemoryManager->deallocate(pThisBlock);//delete [] pThisBlock;
        }
        blockListPtr = 0;
        freeListPtr  = 0;
    }


};


void DOMStringHandle::addRef()
{
    XMLPlatformUtils::atomicIncrement(fRefCount);
};


void DOMStringHandle::removeRef()
{
    int result = XMLPlatformUtils::atomicDecrement(fRefCount);
    if (result==0)
    {
        fDSData->removeRef();
//        delete this;
        DOMStringHandle* ptr = this;
        delete ptr;
    };
};


DOMStringHandle *DOMStringHandle::createNewStringHandle(unsigned int bufLength)
{
    DOMStringHandle  *h = new DOMStringHandle;
    XMLPlatformUtils::atomicIncrement(DOMString::gTotalStringHandleCount);
    h -> fLength = 0;
    h -> fRefCount = 1;
    h -> fDSData = DOMStringData::allocateBuffer(bufLength);
    return h;
};


DOMStringHandle *DOMStringHandle::cloneStringHandle()
{
    DOMStringHandle *h = new DOMStringHandle;
    h->fLength   = fLength;
    h->fRefCount = 1;
    h->fDSData   = fDSData;
    h->fDSData->addRef();
    return h;
}

//------------------------------------------------------------
//
//      DOMString
//
//------------------------------------------------------------


DOMString::DOMString()
{
    fHandle = 0;
};


DOMString::DOMString(const DOMString &other)
{
    fHandle = other.fHandle;
    if (fHandle)
        fHandle->addRef();
};


DOMString::DOMString(const XMLCh *data)
{
    fHandle = 0;
    if (data != 0)
    {
        unsigned int dataLength = 0;
        while (data[dataLength] != 0)
            ++dataLength;

        if (dataLength != 0)
        {
            fHandle = DOMStringHandle::createNewStringHandle(dataLength+1);
            fHandle->fLength = dataLength;
            XMLCh *strData = fHandle->fDSData->fData;
            unsigned int i;
            for (i=0; i<dataLength ; ++i)
                strData[i] = data[i];

            strData[dataLength] = 0;
        }
    }
}



DOMString::DOMString(const XMLCh *data, unsigned int dataLength)
{
    fHandle = 0;
    if (data != 0)
    {
        if (dataLength > 0)
        {
            fHandle = DOMStringHandle::createNewStringHandle(dataLength+1);
            fHandle->fLength = dataLength;
            XMLCh *strData = fHandle->fDSData->fData;
            unsigned int i;
            for (i=0; i<dataLength ; ++i)
                strData[i] = data[i];

            strData[dataLength] = 0;
        }
    }
}




//
//  Create a DOMString from a char * string in the default code page
//                     of the system on which we are executing.
//
//
DOMString::DOMString(const char *srcString)
{
    fHandle = 0;
    if (srcString != 0)
    {
        XMLLCPTranscoder*  uniConverter = getDomConverter();

        unsigned int srcLen = strlen(srcString);