/******************************************************************************

 *

 * 

 *

 * Copyright (C) 1997-2001 by Dimitri van Heesch.

 *

 * Permission to use, copy, modify, and distribute this software and its

 * documentation under the terms of the GNU General Public License is hereby 

 * granted. No representations are made about the suitability of this software 

 * for any purpose. It is provided "as is" without express or implied warranty.

 * See the GNU General Public License for more details.

 *

 * Documents produced by Doxygen are derivative works derived from the

 * input used in their production; they are not affected by this license.

 *

 * Based on qfile_unix.cpp 

 *

 * Copyright (C) 1992-2000 Trolltech AS.

 */

#include "qglobal.h"

#include "qfile.h"

#include "qfiledefs_p.h"

#if defined(_OS_MAC_) || defined(_OS_MSDOS_) || defined(_OS_WIN32_) || defined(_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

bool qt_file_access( const QString& fn, int t )

{

    if ( fn.isEmpty() )

	return FALSE;

    return ACCESS( QFile::encodeName(fn), t ) == 0;

}

/*!

  Removes the file \a fileName.

  Returns TRUE if successful, otherwise FALSE.

*/

bool QFile::remove( const QString &fileName )

{

    if ( fileName.isEmpty() ) {

#if defined(CHECK_NULL)

	qWarning( "QFile::remove: Empty or null file name" );

#endif

	return FALSE;

    }

    return ::remove( QFile::encodeName(fileName) ) == 0;	

    // unlink more common in UNIX

}

#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

/*!

  Opens the file specified by the file name currently set, using the mode \e m.

  Returns TRUE if successful, otherwise FALSE.

  The mode parameter \e m must be a combination of the following flags:

  <ul>

  <li>\c IO_Raw specified raw (non-buffered) file access.

  <li>\c IO_ReadOnly opens the file in read-only mode.

  <li>\c IO_WriteOnly opens the file in write-only mode (and truncates).

  <li>\c IO_ReadWrite opens the file in read/write mode, equivalent to

  \c (IO_ReadOnly|IO_WriteOnly).

  <li>\c IO_Append opens the file in append mode. This mode is very useful

  when you want to write something to a log file. The file index is set to

  the end of the file. Note that the result is undefined if you position the

  file index manually using at() in append mode.

  <li>\c IO_Truncate truncates the file.

  <li>\c IO_Translate enables carriage returns and linefeed translation

  for text files under MS-DOS, Windows and OS/2.

  </ul>

  The raw access mode is best when I/O is block-operated using 4kB block size

  or greater. Buffered access works better when reading small portions of

  data at a time.

  <strong>Important:</strong> When working with buffered files, data may

  not be written to the file at once. Call \link flush() flush\endlink

  to make sure the data is really written.

  \warning We have experienced problems with some C libraries when a buffered

  file is opened for both reading and writing. If a read operation takes place

  immediately after a write operation, the read buffer contains garbage data.

  Worse, the same garbage is written to the file. Calling flush() before

  readBlock() solved this problem.

  If the file does not exist and \c IO_WriteOnly or \c IO_ReadWrite is

  specified, it is created.

  Example:

  \code

    QFile f1( "/tmp/data.bin" );

    QFile f2( "readme.txt" );

    f1.open( IO_Raw | IO_ReadWrite | IO_Append );

    f2.open( IO_ReadOnly | IO_Translate );

  \endcode

  \sa name(), close(), isOpen(), flush()

*/

bool QFile::open( int m )

{

    if ( isOpen() ) {				// file already open

#if defined(CHECK_STATE)

	qWarning( "QFile::open: File already open" );

#endif

	return FALSE;

    }

    if ( fn.isNull() ) {			// no file name defined

#if defined(CHECK_NULL)

	qWarning( "QFile::open: No file name specified" );

#endif

	return FALSE;

    }

    init();					// reset params

    setMode( m );

    if ( !(isReadable() || isWritable()) ) {

#if defined(CHECK_RANGE)

	qWarning( "QFile::open: File access not specified" );

#endif

	return FALSE;

    }

    bool ok = TRUE;

    STATBUF st;

    if ( isRaw() ) {				// raw file I/O

	int oflags = OPEN_RDONLY;

	if ( isReadable() && isWritable() )

	    oflags = OPEN_RDWR;

	else if ( isWritable() )

	    oflags = OPEN_WRONLY;

	if ( flags() & IO_Append ) {		// append to end of file?

	    if ( flags() & IO_Truncate )

		oflags |= (OPEN_CREAT | OPEN_TRUNC);

	    else

		oflags |= (OPEN_APPEND | OPEN_CREAT);

	    setFlags( flags() | IO_WriteOnly ); // append implies write

	} else if ( isWritable() ) {		// create/trunc if writable

	    if ( flags() & IO_Truncate )

		oflags |= (OPEN_CREAT | OPEN_TRUNC);

	    else

		oflags |= OPEN_CREAT;

	}

#if defined(HAS_TEXT_FILEMODE)

	if ( isTranslated() )

	    oflags |= OPEN_TEXT;

	else

	    oflags |= OPEN_BINARY;

#endif

#if defined(HAS_ASYNC_FILEMODE)

	if ( isAsynchronous() )

	    oflags |= OPEN_ASYNC;

#endif

	fd = OPEN( QFile::encodeName(fn), oflags, 0666 );

	if ( fd != -1 ) {			// open successful

	    FSTAT( fd, &st ); // get the stat for later usage

	} else {

	    ok = FALSE;

	}

    } else {					// buffered file I/O

	QCString perm;

	char perm2[4];

	bool try_create = FALSE;

	if ( flags() & IO_Append ) {		// append to end of file?

	    setFlags( flags() | IO_WriteOnly ); // append implies write

	    perm = isReadable() ? "a+" : "a";

	} else {

	    if ( isReadWrite() ) {

		if ( flags() & IO_Truncate ) {

		    perm = "w+";

		} else {

		    perm = "r+";

		    try_create = TRUE;		// try to create if not exists

		}

	    } else if ( isReadable() ) {

		perm = "r";

	    } else if ( isWritable() ) {

		perm = "w";

	    }

	}

	qstrcpy( perm2, perm );

	if ( isTranslated() )

	    strcat( perm2, "t" );

	else

	    strcat( perm2, "b" );

	while (1) { // At most twice

	    fh = fopen( QFile::encodeName(fn), perm2 );

	    if ( !fh && try_create ) {

		perm2[0] = 'w';			// try "w+" instead of "r+"

		try_create = FALSE;

	    } else {

		break;

	    }

	}

	if ( fh ) {

	    FSTAT( FILENO(fh), &st ); // get the stat for later usage

	} else {

	    ok = FALSE;

	}

    }

    if ( ok ) {

	setState( IO_Open );

	// on successful open the file stat was got; now test what type

	// of file we have

	if ( (st.st_mode & STAT_MASK) != STAT_REG ) {

	    // non-seekable

	    setType( IO_Sequential );

	    length = INT_MAX;

	    ioIndex  = (flags() & IO_Append) == 0 ? 0 : length;

	} else {

	    length = (int)st.st_size;

	    ioIndex  = (flags() & IO_Append) == 0 ? 0 : length;

	    if ( (flags() & !IO_Truncate) && length == 0 && isReadable() ) {

		// try if you can read from it (if you can, it's a sequential

		// device; e.g. a file in the /proc filesystem)

		int c = getch();

		if ( c != -1 ) {

		    ungetch(c);

		    setType( IO_Sequential );

		    length = INT_MAX;

		}

	    }

	}

    } else {

	init();

	if ( errno == EMFILE )			// no more file handles/descrs

	    setStatus( IO_ResourceError );

	else

	    setStatus( IO_OpenError );

    }

    return ok;

}

/*!

  Opens a file in the mode \e m using an existing file handle \e f.

  Returns TRUE if successful, otherwise FALSE.

  Example:

  \code

    #include <stdio.h>

    void printError( const char* msg )

    {

	QFile f;

	f.open( IO_WriteOnly, stderr );

	f.writeBlock( msg, qstrlen(msg) );	// write to stderr

	f.close();

    }

  \endcode

  When a QFile is opened using this function, close() does not actually

  close the file, only flushes it.

  \warning If \e f is \c stdin, \c stdout, \c stderr, you may not

  be able to seek.  See QIODevice::isSequentialAccess() for more

  information.

  \sa close()

*/

bool QFile::open( int m, FILE *f )

{

    if ( isOpen() ) {

#if defined(CHECK_RANGE)

	qWarning( "QFile::open: File already open" );

#endif

	return FALSE;

    }

    init();

    setMode( m &~IO_Raw );

    setState( IO_Open );

    fh = f;

    ext_f = TRUE;

    STATBUF st;

    FSTAT( FILENO(fh), &st );

    ioIndex = (int)ftell( fh );

    if ( (st.st_mode & STAT_MASK) != STAT_REG ) {

	// non-seekable

	setType( IO_Sequential );

	length = INT_MAX;

    } else {

	length = (int)st.st_size;

	if ( (flags() & !IO_Truncate) && length == 0 && isReadable() ) {

	    // try if you can read from it (if you can, it's a sequential

	    // device; e.g. a file in the /proc filesystem)

	    int c = getch();

	    if ( c != -1 ) {

		ungetch(c);

		setType( IO_Sequential );

		length = INT_MAX;

	    }

	}

    }

    return TRUE;

}

/*!

  Opens a file in the mode \e m using an existing file descriptor \e f.

  Returns TRUE if successful, otherwise FALSE.

  When a QFile is opened using this function, close() does not actually

  close the file.

  \warning If \e f is one of 0 (stdin), 1 (stdout) or 2 (stderr), you may not

  be able to seek. size() is set to \c INT_MAX (in limits.h).

  \sa close()

*/

bool QFile::open( int m, int f )

{

    if ( isOpen() ) {

#if defined(CHECK_RANGE)

	qWarning( "QFile::open: File already open" );

#endif

	return FALSE;

    }

    init();

    setMode( m |IO_Raw );

    setState( IO_Open );

    fd = f;

    ext_f = TRUE;

    STATBUF st;

    FSTAT( fd, &st );

    ioIndex  = (int)LSEEK(fd, 0, SEEK_CUR);

    if ( (st.st_mode & STAT_MASK) != STAT_REG ) {

	// non-seekable

	setType( IO_Sequential );

	length = INT_MAX;

    } else {

	length = (int)st.st_size;

	if ( length == 0 && isReadable() ) {

	    // try if you can read from it (if you can, it's a sequential

	    // device; e.g. a file in the /proc filesystem)

	    int c = getch();

	    if ( c != -1 ) {

		ungetch(c);

		setType( IO_Sequential );

		length = INT_MAX;

	    }

	}

    }

    return TRUE;

}

/*!

  Returns the file size.

  \sa at()

*/

uint QFile::size() const

{

    STATBUF st;

    if ( isOpen() ) {

	FSTAT( fh ? FILENO(fh) : fd, &st );

    } else {

	STAT( QFile::encodeName(fn), &st );

    }

    return st.st_size;

}

/*!

  \fn int QFile::at() const

  Returns the file index.

  \sa size()

*/

/*!

  Sets the file index to \e pos. Returns TRUE if successful, otherwise FALSE.

  Example:

  \code

    QFile f( "data.bin" );

    f.open( IO_ReadOnly );			// index set to 0

    f.at( 100 );				// set index to 100

    f.at( f.at()+50 );				// set index to 150

    f.at( f.size()-80 );			// set index to 80 before EOF

    f.close();

  \endcode

  \warning The result is undefined if the file was \link open() opened\endlink

  using the \c IO_Append specifier.

  \sa size(), open()

*/

bool QFile::at( int pos )

{

    if ( !isOpen() ) {

#if defined(CHECK_STATE)

	qWarning( "QFile::at: File is not open" );

#endif

	return FALSE;

    }

    bool ok;

    if ( isRaw() ) {				// raw file

	pos = (int)LSEEK(fd, pos, SEEK_SET);

	ok = pos != -1;

    } else {					// buffered file

	ok = fseek(fh, pos, SEEK_SET) == 0;

    }

    if ( ok )

	ioIndex = pos;

#if defined(CHECK_RANGE)

    else

	qWarning( "QFile::at: Cannot set file position %d", pos );

#endif

    return ok;

}

/*!

  Reads at most \e len bytes from the file into \e p and returns the

  number of bytes actually read.

  Returns -1 if a serious error occurred.

  \warning We have experienced problems with some C libraries when a buffered

  file is opened for both reading and writing. If a read operation takes place

  immediately after a write operation, the read buffer contains garbage data.

  Worse, the same garbage is written to the file. Calling flush() before

  readBlock() solved this problem.

  \sa writeBlock()

*/

int QFile::readBlock( char *p, uint len )

{

#if defined(CHECK_NULL)

    if ( !p )

	qWarning( "QFile::readBlock: Null pointer error" );

#endif

#if defined(CHECK_STATE)

    if ( !isOpen() ) {				// file not open

	qWarning( "QFile::readBlock: File not open" );

	return -1;

    }

    if ( !isReadable() ) {			// reading not permitted

	qWarning( "QFile::readBlock: Read operation not permitted" );

	return -1;

    }

#endif

    int nread;					// number of bytes read

    if ( isRaw() ) {				// raw file

	nread = READ( fd, p, len );

	if ( len && nread <= 0 ) {

	    nread = 0;

	    setStatus(IO_ReadError);

	}

    } else {					// buffered file

	nread = fread( p, 1, len, fh );

	if ( (uint)nread != len ) {

	    if ( ferror( fh ) || nread==0 )

		setStatus(IO_ReadError);

	}

    }

    ioIndex += nread;

    return nread;

}

/*! \overload int writeBlock( const QByteArray& data )

*/

/*! \reimp

  Writes \e len bytes from \e p to the file and returns the number of

  bytes actually written.

  Returns -1 if a serious error occurred.

  \warning When working with buffered files, data may not be written

  to the file at once. Call flush() to make sure the data is really

  written.

  \sa readBlock()

*/

int QFile::writeBlock( const char *p, uint len )

{

#if defined(CHECK_NULL)

    if ( p == 0 && len != 0 )

	qWarning( "QFile::writeBlock: Null pointer error" );

#endif

#if defined(CHECK_STATE)

    if ( !isOpen() ) {				// file not open

	qWarning( "QFile::writeBlock: File not open" );

	return -1;

    }

    if ( !isWritable() ) {			// writing not permitted

	qWarning( "QFile::writeBlock: Write operation not permitted" );

	return -1;

    }

#endif

    int nwritten;				// number of bytes written

    if ( isRaw() )				// raw file

	nwritten = WRITE( fd, p, len );

    else					// buffered file

	nwritten = fwrite( p, 1, len, fh );

    if ( nwritten != (int)len ) {		// write error

	if ( errno == ENOSPC )			// disk is full

	    setStatus( IO_ResourceError );

	else

	    setStatus( IO_WriteError );

	if ( isRaw() )				// recalc file position

	    ioIndex = (int)LSEEK( fd, 0, SEEK_CUR );

	else

	    ioIndex = fseek( fh, 0, SEEK_CUR );

    } else {

	ioIndex += nwritten;

    }