Function Call Tracing in JScript

/***************************************************************************
*
*	File            : MemoryMappedFile.h
*	Author          : K. Skilling
*	Description     : Memory mapped file wrapper class.
*
*	Change History
*	---------------
*	KS	7/16/99	CREATED
*   KS  6/05/04 dwBytesToMap - if this is zero the entire file is mapped, 
*               otherwise just maps a portion
*	KS  8/11/05 m_szFilePath as LPCTSTR
*****************************************************************************/
#include "MemoryMappedFile.h"

CMemoryMappedFile::CMemoryMappedFile(void)
{
	_Init();
}

// KS/06/05/04 dwBytesToMap
CMemoryMappedFile::CMemoryMappedFile(LPCTSTR pszFileName,BOOL boModifiable /*=FALSE*/,DWORD dwBytesToMap /*=0*/)
{
   // Given a filename, the constructor opens a file handle, creates a file
    // mapping, and maps the entire file into memory.
 
	_Init();
	_OpenFile(pszFileName,boModifiable,dwBytesToMap);
}

CMemoryMappedFile::~CMemoryMappedFile(void)
{
	if (eFILEOPEN != m_errCode)
		_Close();
}

void CMemoryMappedFile::_Close()
{
    // Clean up everything that was created by the constructor
    if ( m_pMemoryMappedFileBase )
        UnmapViewOfFile( m_pMemoryMappedFileBase );

    if ( m_hFileMapping )
        CloseHandle( m_hFileMapping );

    if ( m_hFile != INVALID_HANDLE_VALUE )
        CloseHandle( m_hFile ); 

    m_errCode = eFILEOPEN;
}

BOOL CMemoryMappedFile::Close()
{
	return eFILEOPEN == m_errCode ? FALSE : _Close(),TRUE;
}

// KS/06/05/04 dwBytesToMap
BOOL CMemoryMappedFile::OpenFile(LPCTSTR lpszFileName,BOOL boModifiable /*=FALSE*/,DWORD dwBytesToMap /*=0*/)
{
	_OpenFile(lpszFileName,boModifiable,dwBytesToMap);
	return eNOERROR == m_errCode ? TRUE : FALSE;
}

// Create a file from the null-terminated string. 
BOOL CMemoryMappedFile::CreateFile(LPCTSTR pszFileName,PVOID pData,DWORD dwLen,BOOL boOverwrite /*=TRUE*/)
{
	BOOL boOK = FALSE;
	__try
	{
		SetLastError(0);

		// First get a file handle      
		DWORD dwAccess = GENERIC_READ | GENERIC_WRITE;

		DWORD dwCreate = boOverwrite ? CREATE_ALWAYS : CREATE_NEW;
		m_hFile = ::CreateFile(pszFileName, dwAccess, FILE_SHARE_READ, NULL,
								dwCreate, FILE_ATTRIBUTE_NORMAL,NULL);
                    
		if ( m_hFile == INVALID_HANDLE_VALUE )
		{
			m_errCode = eFILEOPEN;
			__leave;
		}

		// Now, create a file mapping 
		// KS/10/02/2004 Allow for 0 len file - just creates it
		if (dwLen > 0)
		{
			m_hFileMapping = ::CreateFileMapping(m_hFile,NULL,PAGE_READWRITE,0,dwLen,NULL);
			if ( m_hFileMapping == 0 )
			{
				m_errCode = eFILEMAPPING;
				__leave;
			}

			// Should have been 'grown' to size required so get the byte size now
			m_cbFile = ::GetFileSize(m_hFile,0);

			m_pMemoryMappedFileBase = (PCHAR)MapViewOfFile( m_hFileMapping,
															FILE_MAP_ALL_ACCESS, 0, 0, 0);

			if ( m_pMemoryMappedFileBase == 0 )
			{
				m_errCode = eMAPVIEW;
				__leave;
			}

			// KS/07/05/04 - Don't necessarily have data to copy in at this point
			if (pData)
				::memcpy(m_pMemoryMappedFileBase,pData,dwLen);
		}

		m_errCode = eNOERROR;
	}
	__finally
	{
		// If any error then cleanup
		if (m_errCode != eNOERROR)
		{
			m_dwLastError = GetLastError();   
			// KS/10/02/03 This is the proper test
			if (INVALID_HANDLE_VALUE != m_hFile)
			{
				CloseHandle(m_hFile);
				m_hFile = INVALID_HANDLE_VALUE;
			}
			m_hFileMapping = 0;
		}
	}

	return eNOERROR == m_errCode ? TRUE : FALSE;
}

void CMemoryMappedFile::_OpenFile(LPCTSTR pszFileName,BOOL boModifiable,DWORD dwBytesToMap /*=0*/)
{
	BOOL boOK = FALSE;
	__try
	{                    
		// KS/10/02/03 Don't want any previous error reported
		SetLastError(0);

		// First get a file handle      
		DWORD dwAccess = GENERIC_READ;
		if (boModifiable) dwAccess |= GENERIC_WRITE;

		m_hFile = ::CreateFile(pszFileName, dwAccess, FILE_SHARE_READ, NULL,
								OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,NULL);
                    
		if ( m_hFile == INVALID_HANDLE_VALUE )
		{
			m_errCode = eFILEOPEN;
			__leave;
		}

		// Now, create a file mapping   
		DWORD dwProtect = boModifiable ? PAGE_READWRITE : PAGE_READONLY;
		m_hFileMapping = ::CreateFileMapping(m_hFile,NULL,dwProtect, 0, 0,NULL);
		if ( m_hFileMapping == 0 )
		{
			m_errCode = eFILEMAPPING;
			__leave;
		}

		DWORD dwMapAccess = boModifiable ? FILE_MAP_ALL_ACCESS : FILE_MAP_READ;
		m_pMemoryMappedFileBase = (PCHAR)MapViewOfFile( m_hFileMapping,
														dwMapAccess, 0, 0, dwBytesToMap);

		if ( m_pMemoryMappedFileBase == 0 )
		{
			m_errCode = eMAPVIEW;
			__leave;
		}

		m_cbFile = ::GetFileSize( m_hFile, 0 );
		m_cbMappedSize = dwBytesToMap;
		_tcscpy(m_szFilePath,pszFileName);

		m_errCode = eNOERROR;
	}
	__finally
	{
		// If any error then cleanup
		if (m_errCode != eNOERROR)
		{
			m_dwLastError = GetLastError();
			if (INVALID_HANDLE_VALUE != m_hFile)
			{
				CloseHandle(m_hFile);
				m_hFile = INVALID_HANDLE_VALUE;
			}
			m_hFileMapping = 0;
		}
	}
}

void CMemoryMappedFile::_Init()
{
    m_hFile = INVALID_HANDLE_VALUE;
    m_hFileMapping = 0;
    m_pMemoryMappedFileBase = 0;
    m_cbFile = 0;
	m_cbMappedSize = 0;
    m_errCode = eFILEOPEN;			 // Initial error code: not found
	m_dwLastError = ERROR_SUCCESS;
	m_szFilePath[0] =  NULL;
}