/****************************************************************************
** $Id: qfile.cpp,v 1.1 2002/03/18 13:37:11 thiagocorrea Exp $
**
** Implementation of QFile class
**
** Created : 930812
**
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** LICENSE.QPL included in the packaging of this file.
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** This file may be distributed and/or modified under the terms of the
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** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
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** licenses may use this file in accordance with the Qt Commercial License
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**********************************************************************/

#include "qplatformdefs.h"

#include "qfile.h"


extern bool qt_file_access( const QString& fn, int t );

/*!
  \class QFile qfile.h
  \brief The QFile class is an I/O device that operates on files.

  \ingroup io
  \mainclass

  QFile is an I/O device for reading and writing binary and text files.	A
  QFile may be used by itself or more conveniently with a QDataStream or
  QTextStream.

  The file name is usually passed in the constructor but can be changed with
  setName(). You can check for a file's existence with exists() and remove a
  file with remove().

  The file is opened with open(), closed with close() and flushed with
  flush(). Data is usually read and written using QDataStream or QTextStream,
  but you can read with readBlock() and readLine() and write with
  writeBlock(). QFile also supports getch(), ungetch() and putch().

  The size of the file is returned by size(). You can get the current file
  position or move to a new file position using the at() functions. If you've
  reached the end of the file, atEnd() returns TRUE. The file handle is
  returned by handle().

  Here is a code fragment that uses QTextStream to read a text
  file line by line. It prints each line with a line number.
  \code
    QFile f("file.txt");
    if ( f.open(IO_ReadOnly) ) {    // file opened successfully
	QTextStream t( &f );	    // use a text stream
	QString s;
	int n = 1;
	while ( !t.eof() ) {	    // until end of file...
	    s = t.readLine();	    // line of text excluding '\n'
	    printf( "%3d: %s\n", n++, s.latin1() );
	}
	f.close();
    }
  \endcode

  The QFileInfo class holds detailed information about a file, such as
  access permissions, file dates and file types.

  The QDir class manages directories and lists of file names.

  Qt uses Unicode file names. If you want to do your own I/O on Unix systems
  you may want to use encodeName() (and decodeName()) to convert the file name
  into the local encoding.

  \important readAll(), writeBlock()

  \sa QDataStream, QTextStream
*/


/*!
  Constructs a QFile with no name.
*/

QFile::QFile()
{
    init();
}

/*!
  Constructs a QFile with a file name \a name.
  \sa setName()
*/

QFile::QFile( const QString &name )
    : fn(name)
{
    init();
}


/*!
  Destroys a QFile.  Calls close().
*/

QFile::~QFile()
{
    close();
}


/*!
  \internal
  Initialize internal data.
*/

void QFile::init()
{
    setFlags( IO_Direct );
    setStatus( IO_Ok );
    fh	   = 0;
    fd	   = 0;
    length = 0;
    ioIndex = 0;
    ext_f  = FALSE;				// not an external file handle
}


/*!
  \fn QString QFile::name() const
  Returns the name set by setName().
  \sa setName(), QFileInfo::fileName()
*/

/*!
  Sets the name of the file to \a name. The name may have no path, a
  relative path or an absolute absolute directory path.

  Do not call this function if the file has already been opened.

  If the file name has no path or a relative path, the path used will be
  whatever the application's current directory path is <em>at the time of the open()</em>
  call.

  Example:
  \code
     QFile f;
     QDir::setCurrent( "/tmp" );
     f.setName( "readme.txt" );
     QDir::setCurrent( "/home" );
     f.open( IO_ReadOnly );	   // opens "/home/readme.txt" under Unix
  \endcode

  Note that the directory separator "/" works for all operating
  systems supported by Qt.

  \sa name(), QFileInfo, QDir
*/

void QFile::setName( const QString &name )
{
    if ( isOpen() ) {
#if defined(QT_CHECK_STATE)
	qWarning( "QFile::setName: File is open" );
#endif
	close();
    }
    fn = name;
}

/*!
    \overload
  Returns TRUE if this file exists; otherwise returns FALSE.
  \sa name()
*/

bool QFile::exists() const
{
    return qt_file_access( fn, F_OK );
}

/*!
  Returns TRUE if the file given by \a fileName exists; otherwise returns
  FALSE.
*/

bool QFile::exists( const QString &fileName )
{
    return qt_file_access( fileName, F_OK );
}


/*!
  Removes the file specified by the file name currently set.
  Returns TRUE if successful; otherwise returns FALSE.

  The file is closed before it is removed.
*/

bool QFile::remove()
{
    close();
    return remove( fn );
}

#if defined(Q_OS_MAC) || defined(Q_OS_MSDOS) || defined(Q_OS_WIN32) || defined(Q_OS_OS2)
# define HAS_TEXT_FILEMODE			// has translate/text filemode
#endif
#if defined(O_NONBLOCK)
# define HAS_ASYNC_FILEMODE
# define OPEN_ASYNC O_NONBLOCK
#elif defined(O_NDELAY)
# define HAS_ASYNC_FILEMODE
# define OPEN_ASYNC O_NDELAY
#endif

/*!
  Flushes the file buffer to the disk.

  close() also flushes the file buffer.
*/

void QFile::flush()
{
    if ( isOpen() && fh )			// can only flush open/buffered
	fflush( fh );				//   file
}

/*!
    \overload QIODevice::Offset QFile::at() const
    Returns the position in the file.
  \sa size()
*/

/*!
  Returns TRUE if the end of file has been reached; otherwise returns FALSE.
  \sa size()
*/

bool QFile::atEnd() const
{
    if ( !isOpen() ) {
#if defined(QT_CHECK_STATE)
	qWarning( "QFile::atEnd: File is not open" );
#endif
	return FALSE;
    }
    if ( isDirectAccess() && !isTranslated() ) {
	if ( at() < length )
	    return FALSE;
    }
    return QIODevice::atEnd();
}

/*!
  Reads a line of text.

  Reads bytes from the file into the char* \a p, until end-of-line or
  \a maxlen bytes have been read, whichever occurs first. Returns the
  number of bytes read, or -1 if there was an error.  The terminating
  newline is not stripped.

  This function is efficient only for buffered files.  Avoid
  readLine() for files that have been opened with the \c IO_Raw
  flag.

  \sa readBlock(), QTextStream::readLine()
*/

Q_LONG QFile::readLine( char *p, Q_ULONG maxlen )
{
    if ( maxlen == 0 )				// application bug?
	return 0;
#if defined(QT_CHECK_STATE)
    Q_CHECK_PTR( p );
    if ( !isOpen() ) {				// file not open
	qWarning( "QFile::readLine: File not open" );
	return -1;
    }
    if ( !isReadable() ) {			// reading not permitted
	qWarning( "QFile::readLine: Read operation not permitted" );
	return -1;
    }
#endif
    Q_LONG nread;				// number of bytes read
    if ( isRaw() ) {				// raw file
	nread = QIODevice::readLine( p, maxlen );
    } else {					// buffered file
	p = fgets( p, maxlen, fh );
	if ( p ) {
	    nread = qstrlen( p );
	    if ( !isSequentialAccess() )
		ioIndex += nread;
	} else {
	    nread = -1;
	    setStatus(IO_ReadError);
	}
    }
    return nread;
}


/*!
    \overload
  Reads a line of text.

  Reads bytes from the file into string \a s, until end-of-line or \a
  maxlen bytes have been read, whichever occurs first. Returns the
  number of bytes read, or -1 if there was an error.g. end of file.
  The terminating newline is not stripped.

  This function is efficient only for buffered files.  Avoid
  readLine() for files that have been opened with the \c IO_Raw
  flag.

  Note that the string is read as plain Latin1 bytes, not Unicode.

  \sa readBlock(), QTextStream::readLine()
*/

Q_LONG QFile::readLine( QString& s, Q_ULONG maxlen )
{
    QByteArray ba(maxlen);
    Q_LONG l = readLine(ba.data(),maxlen);
    if ( l >= 0 ) {
	ba.truncate(l);
	s = QString(ba);
    }
    return l;
}


/*!
  Reads a single byte/character from the file.

  Returns the byte/character read, or -1 if the end of the file has been
  reached.

  \sa putch(), ungetch()
*/

int QFile::getch()
{
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {				// file not open
	qWarning( "QFile::getch: File not open" );
	return EOF;
    }
    if ( !isReadable() ) {			// reading not permitted
	qWarning( "QFile::getch: Read operation not permitted" );
	return EOF;
    }
#endif

    int ch;

    if ( !ungetchBuffer.isEmpty() ) {
	int len = ungetchBuffer.length();
	ch = ungetchBuffer[ len-1 ];
	ungetchBuffer.truncate( len - 1 );
	return ch;
    }

    if ( isRaw() ) {				// raw file (inefficient)
	char buf[1];
	ch = readBlock( buf, 1 ) == 1 ? buf[0] : EOF;
    } else {					// buffered file
	if ( (ch = getc( fh )) != EOF )
	    if ( !isSequentialAccess() )
		ioIndex++;
	else
	    setStatus(IO_ReadError);
    }
    return ch;
}

/*!
  Writes the character \a ch to the file.

  Returns \a ch, or -1 if some error occurred.

  \sa getch(), ungetch()
*/

int QFile::putch( int ch )
{
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {				// file not open
	qWarning( "QFile::putch: File not open" );
	return EOF;
    }
    if ( !isWritable() ) {			// writing not permitted
	qWarning( "QFile::putch: Write operation not permitted" );
	return EOF;
    }
#endif
    if ( isRaw() ) {				// raw file (inefficient)
	char buf[1];
	buf[0] = ch;
	ch = writeBlock( buf, 1 ) == 1 ? ch : EOF;
    } else {					// buffered file
	if ( (ch = putc( ch, fh )) != EOF ) {
	    if ( !isSequentialAccess() )
		ioIndex++;
	    if ( ioIndex > length )		// update file length
		length = ioIndex;
	} else {
	    setStatus(IO_WriteError);
	}
    }
    return ch;
}

/*!
  Puts the character \a ch back into the file and decrements the index if it
  is not zero.

  This function is normally called to "undo" a getch() operation.

  Returns \a ch, or -1 if some error occurred.

  \sa getch(), putch()
*/

int QFile::ungetch( int ch )
{
#if defined(QT_CHECK_STATE)
    if ( !isOpen() ) {				// file not open
	qWarning( "QFile::ungetch: File not open" );
	return EOF;
    }
    if ( !isReadable() ) {			// reading not permitted
	qWarning( "QFile::ungetch: Read operation not permitted" );
	return EOF;
    }
#endif
    if ( ch == EOF )				// cannot unget EOF
	return ch;

    if ( isSequentialAccess() && !fh) {
	// pipe or similar => we cannot ungetch, so do it manually
	ungetchBuffer +=ch;
	return ch;
    }

    if ( isRaw() ) {				// raw file (very inefficient)
	char buf[1];
	at( ioIndex-1 );
	buf[0] = ch;
	if ( writeBlock(buf, 1) == 1 )
	    at ( ioIndex-1 );
	else
	    ch = EOF;
    } else {					// buffered file
	if ( (ch = ungetc(ch, fh)) != EOF )
	    if ( !isSequentialAccess() )
		ioIndex--;
	else
	    setStatus( IO_ReadError );
    }
    return ch;
}


static QCString locale_encoder( const QString &fileName )
{
    return fileName.local8Bit();
}


static QFile::EncoderFn encoder = locale_encoder;

/*!
  When you use QFile, QFileInfo, and QDir to access the file system
  with Qt, you can use Unicode file names.  On Unix, these file names
  are converted to an 8-bit encoding.  If you want to do your own
  file I/O on Unix, you should convert the file name using this
  function.  On Windows NT, Unicode file names are supported directly
  in the file system and this function should be avoided. On Windows 95,
  non-Latin1 locales are not supported at this time.

  By default, this function converts \a fileName to the local 8-bit
  encoding determined by the user's locale.  This is sufficient for
  file names that the user chooses.  File names hard-coded into the
  application should only use 7-bit ASCII filename characters.

  The conversion scheme can be changed using setEncodingFunction().
  This might be useful if you wish to give the user an option to
  store file names in utf-8, etc., but be ware that such file names
  would probably then be unrecognizable when seen by other programs.

  \sa decodeName()
*/

QCString QFile::encodeName( const QString &fileName )
{
    return (*encoder)(fileName);
}

/*!
  \enum QFile::EncoderFn

  This is used by QFile::setEncodingFunction().
*/

/*!
  Sets the function for encoding Unicode file names to \a f.
  The default encodes in the locale-specific 8-bit encoding.

  \sa encodeName()
*/
void QFile::setEncodingFunction( EncoderFn f )
{
    encoder = f;
}

static
QString locale_decoder( const QCString &localFileName )
{
    return QString::fromLocal8Bit(localFileName);
}

static QFile::DecoderFn decoder = locale_decoder;

/*!
  This does the reverse of QFile::encodeName() using \a localFileName.

  \sa setDecodingFunction()
*/
QString QFile::decodeName( const QCString &localFileName )
{
    return (*decoder)(localFileName);
}

/*!
  \enum QFile::DecoderFn

  This is used by QFile::setDecodingFunction().
*/

/*!
  Sets the function for decoding 8-bit file names to \a f.
  The default uses the locale-specific 8-bit encoding.

  \sa encodeName(), decodeName()
*/

void QFile::setDecodingFunction( DecoderFn f )
{
    decoder = f;
}

