mmapdatf.cpp

linux下的一款播放器

	/*
	 * File may be mapped and we are trying to truncate it.
	 * It will only let us do that if we unmap the file NOW.
	 *
	if (uOpenMode & HX_FILE_WRITE && dwCreate == CREATE_ALWAYS)
	{
	    _AttemptUnmap();

	    /*
	     * We are now going to open the file, so make
	     * sure there is always a read mixed this this write.
	     *
	    dwFlags |= GENERIC_READ;
	    dwShare |= FILE_SHARE_READ;
	}

	/*
	 * Try and re-open the file.  This will either be read only
	 * if we failed reading, in case it is a readonly file,
	 * of it could be another attempt at "w" after unampping
	 * the file.  All vars are set up for either case.
	 *
	m_hFile = CreateFile(m_pFilename,
	    dwFlags,
	    dwShare,
	    NULL,
	    dwCreate,
	    FILE_ATTRIBUTE_NORMAL,
	    NULL);

	if (m_hFile == INVALID_HANDLE_VALUE)
	{
	    return HXR_FAIL;
	}
    }
    m_ulPos = 0;

    if (MmapHandle)
    {
	m_zpMMM->CloseMap(MmapHandle);
	MmapHandle = 0;
    }
    MmapHandle = m_zpMMM->OpenMap(m_hFile, m_pContext);

    return HXR_OK;
}
*/

/* Delete File */
STDMETHODIMP
MemoryMapDataFile::Delete()
{
    Close();
    if (!m_pFilename)
    {
	return HXR_UNEXPECTED;
    }
    if (DeleteFile(OS_STRING(m_pFilename)))
    {
	return HXR_OK;
    }
    else if (_AttemptUnmap())
    {
        if (DeleteFile(OS_STRING(m_pFilename)))
	{
	    return HXR_OK;
	}
    }
    return HXR_FAIL;
}


/* Close closes a file 
 * If the reference count on the IHXDataFile object is greater than 1, 
 * then the underlying file cannot be safely closed, so Close() becomes 
 * a noop in that case. Close it only when the object is destroyed. 
 * This would be safe, but could lead to a file descriptor leak.
 */
STDMETHODIMP
MemoryMapDataFile::Close()
{
    m_ulLastError = HXR_OK;

    if (m_hFile != INVALID_HANDLE_VALUE)
    {
	CloseHandle(m_hFile);
	m_hFile = INVALID_HANDLE_VALUE;
    }
    m_ulPos = -1;

    if (MmapHandle)
    {
	m_zpMMM->CloseMap(MmapHandle);
	MmapHandle = 0;
    }

    return HXR_OK;
}

/* Name returns the currently bound file name in FileName.
 * and returns TRUE, if the a name has been bound.  Otherwise
 * FALSE is returned.
 */
STDMETHODIMP_(BOOL)
MemoryMapDataFile::Name(REF(IHXBuffer*) pFileName)
{
    if (!m_pFilename)
    {
	return FALSE;
    }
    pFileName = new CHXBuffer();
    pFileName->AddRef();
    pFileName->Set((const unsigned char*)m_pFilename,
	strlen(m_pFilename) + 1);

    return TRUE;
}

/*
 * IsOpen returns TRUE if file is open.  Otherwise FALSE.
 */
STDMETHODIMP_(BOOL)
MemoryMapDataFile::IsOpen()
{
    if (m_hFile != INVALID_HANDLE_VALUE)
    {
	return TRUE;
    }
    return FALSE;
}

/* Seek moves the current file position to the offset from the
 * fromWhere specifier returns current position of file or -1 on
 * error.
 */
STDMETHODIMP
MemoryMapDataFile::Seek(ULONG32 offset, UINT16 fromWhere)
{
    LONG32 lHighOffset = 0;
    m_ulLastError = HXR_OK;

    DWORD fw = 0;
    switch (fromWhere)
    {
	case SEEK_CUR:
	    fw = FILE_CURRENT;
	    m_ulPos += offset;
	    if (((LONG32) offset) < 0)
	    {
		lHighOffset = -1;
	    }
	    break;

	case SEEK_END:
	    fw = FILE_END;
	    if (offset > m_ulPos)
	    {
		m_ulPos = 0;
	    }
	    else
	    {
		m_ulPos -= offset;
	    }
	    break;

	case SEEK_SET:
	    fw = FILE_BEGIN;
	    m_ulPos = offset;
	    break;
    }

    DWORD dwRet = SetFilePointer(m_hFile, offset, &lHighOffset, fw);
    if (dwRet == -1)
    {
	if (GetLastError() != NO_ERROR)
	{
	    m_ulPos = -1;
	    m_ulLastError = HXR_FAIL;
	    return HXR_FAIL;
	}
    }
    
    return 0;
}

/* Tell returns the current file position in the file */
STDMETHODIMP_(ULONG32)
MemoryMapDataFile::Tell()
{
    m_ulLastError = HXR_OK;
    return m_ulPos;
}

void MemoryMapDataFile::StopMmap()
{
    if (MmapHandle == NULL)
	return;
    m_zpMMM->CloseMap(MmapHandle);
    MmapHandle = 0;
    Seek(m_ulPos, SEEK_SET);
}

/* Read reads up to count bytes of data into buf.
 * returns the number of bytes read, EOF, or -1 if the read failed 
 */
STDMETHODIMP_(ULONG32)
MemoryMapDataFile::Read(REF(IHXBuffer*) pBuf, 
		ULONG32 count)
{
    m_ulLastError = HXR_OK;

    if (!(m_uOpenMode & HX_FILE_READ))
    {
	return 0;
    }
    UINT32 ulRead = 0;

    if (MmapHandle)
    {
	ulRead = m_zpMMM->GetBlock(pBuf, MmapHandle, m_ulPos, count);
	if (ulRead >= MMAP_EXCEPTION)
	{
	    if (ulRead != MMAP_EOF_EXCEPTION)
	    {
		StopMmap();
	    }
	    else
	    {
		Seek(m_ulPos, SEEK_SET);
	    }

	    goto normal_read;
	}
	if (ulRead > 0)
	{
	    m_ulPos += ulRead;
	}
	return ulRead;
    }

normal_read:

    if (m_hFile == INVALID_HANDLE_VALUE)
    {
	pBuf = NULL;
	return 0;
    }
    pBuf = new CHXBuffer;
    pBuf->AddRef();
    pBuf->SetSize(count);
    if (!ReadFile(m_hFile, (void*)pBuf->GetBuffer(), count, &ulRead, NULL))
    {
        m_ulLastError = HXR_FAIL;
    }

    m_ulPos += ulRead;

    if (ulRead < count)
    {
        pBuf->SetSize(ulRead);
    }

    return ulRead;
}


/* Write writes up to count bytes of data from buf.
 * returns the number of bytes written, or -1 if the write failed 
 */
STDMETHODIMP_(ULONG32)
MemoryMapDataFile::Write(REF(IHXBuffer*) pBuf)
{
    m_ulLastError = HXR_OK;

    if (!(m_uOpenMode & HX_FILE_WRITE))
    {
	return 0;
    }
    StopMmap();

    UINT32 ulWritten = 0;
    if (m_hFile == INVALID_HANDLE_VALUE)
    {
	return 0;
    }
    if (!WriteFile(m_hFile, (void*)pBuf->GetBuffer(), pBuf->GetSize(),
                   &ulWritten, NULL))
    {
        m_ulLastError = HXR_FAIL;
    }

    return ulWritten;
}

/* Flush out the data in case of unbuffered I/O
 */
STDMETHODIMP
MemoryMapDataFile::Flush()
{
    StopMmap();

    return HXR_NOTIMPL;
}

/*
 * Return info about the data file such as permissions, time of creation
 * size in bytes, etc.
 */

STDMETHODIMP
MemoryMapDataFile::Stat(struct stat* buffer)
{
    if (!m_pFilename)
    {
	return HXR_UNEXPECTED;
    }
    BOOL bClose = FALSE;
    HANDLE hUse = m_hFile;
    if (hUse == INVALID_HANDLE_VALUE)
    {
	bClose = TRUE;
	hUse = CreateFile(OS_STRING(m_pFilename),
		0, //query
		FILE_SHARE_READ,
		NULL,
		OPEN_EXISTING,
		FILE_ATTRIBUTE_NORMAL,
		NULL);
    }

    if (hUse == INVALID_HANDLE_VALUE)
    {
	return HXR_FAIL;
    }

    BY_HANDLE_FILE_INFORMATION mss;
    memset(buffer, 0, sizeof(*buffer));

    buffer->st_nlink = 1;
    
    HX_RESULT res;
    if (GetFileInformationByHandle(hUse,
	    &mss))
    {
	buffer->st_atime = FileTimeTotime_t(&mss.ftLastAccessTime);
	buffer->st_ctime = FileTimeTotime_t(&mss.ftCreationTime);
	buffer->st_mtime = FileTimeTotime_t(&mss.ftLastWriteTime);
	buffer->st_size  = mss.nFileSizeLow;
	res = HXR_OK;
    }
    else
    {
	res = HXR_FAIL;
    }

    if (bClose)
    {
	CloseHandle(hUse);
    }

    return res;

}

/* Return the file descriptor */
STDMETHODIMP_(INT16)
MemoryMapDataFile::GetFd()
{
    if (m_hFile != INVALID_HANDLE_VALUE)
    {
	return 1;
    }
    return -1;
}

/* GetLastError returns the platform specific file error */
STDMETHODIMP
MemoryMapDataFile::GetLastError()
{
    return m_ulLastError;
}

/* GetLastError returns the platform specific file error in
 * string form.
 */
STDMETHODIMP_(void)
MemoryMapDataFile::GetLastError(REF(IHXBuffer*) err)
{
    err = 0;
    return;
}

BOOL
MemoryMapDataFile::_AttemptUnmap()
{
    HANDLE hFile;
    hFile = CreateFile(OS_STRING(m_pFilename),
	    GENERIC_READ,
	    FILE_SHARE_READ |
		(g_NT ? FILE_SHARE_DELETE : 0),
	    NULL,
	    OPEN_EXISTING,
	    FILE_ATTRIBUTE_NORMAL,
	    NULL);
    if (hFile == INVALID_HANDLE_VALUE)
    {
	return FALSE;
    }
    void* pHandle = m_zpMMM->GetMMHandle(hFile);
    CloseHandle(hFile);
    if (!pHandle)
    {
	return FALSE;
    }
    m_zpMMM->AttemptCloseMapNow(pHandle);
    return TRUE;
}