/****************************************************************************** * * $Id$ * * 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" 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: 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. Important: 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 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; } if ( ioIndex > length ) // update file length length = ioIndex; return nwritten; } /*! Returns the file handle of the file. This is a small positive integer, suitable for use with C library functions such as fdopen() and fcntl(), as well as with QSocketNotifier. If the file is not open or there is an error, handle() returns -1. \sa QSocketNotifier */ int QFile::handle() const { if ( !isOpen() ) return -1; else if ( fh ) return FILENO( fh ); else return fd; } /*! Closes an open file. The file is not closed if it was opened with an existing file handle. If the existing file handle is a \c FILE*, the file is flushed. If the existing file handle is an \c int file descriptor, nothing is done to the file. Some "write-behind" filesystems may report an unspecified error on closing the file. These errors only indicate that something may have gone wrong since the previous open(). In such a case status() reports IO_UnspecifiedError after close(), otherwise IO_Ok. \sa open(), flush() */ void QFile::close() { bool ok = FALSE; if ( isOpen() ) { // file is not open if ( fh ) { // buffered file if ( ext_f ) ok = fflush( fh ) != -1; // flush instead of closing else ok = fclose( fh ) != -1; } else { // raw file if ( ext_f ) ok = TRUE; // cannot close else ok = CLOSE( fd ) != -1; } init(); // restore internal state } if (!ok) setStatus (IO_UnspecifiedError); return; }