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tqt3/src/tools/qfile_unix.cpp

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19 KiB

/****************************************************************************
**
** Implementation of TQFile class
**
** Created : 950628
**
** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the tools module of the TQt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free TQt Foundation.
**
** Please review the following information to ensure GNU General
** Public Licensing retquirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/.
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** This file may be used under the terms of the Q Public License as
** defined by Trolltech ASA and appearing in the file LICENSE.TQPL
** included in the packaging of this file. Licensees holding valid TQt
** Commercial licenses may use this file in accordance with the TQt
** Commercial License Agreement provided with the Software.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
** herein.
**
**********************************************************************/
#include "qplatformdefs.h"
// POSIX Large File Support redefines open -> open64
static inline int qt_open(const char *pathname, int flags, mode_t mode)
{ return ::open(pathname, flags, mode); }
#if defined(open)
# undef open
#endif
// POSIX Large File Support redefines truncate -> truncate64
#if defined(truncate)
# undef truncate
#endif
#include "qfile.h"
#include <errno.h>
#include <limits.h>
extern const char* qt_fileerr_read;
bool qt_file_access( const TQString& fn, int t )
{
if ( fn.isEmpty() )
return FALSE;
return ::access( TQFile::encodeName(fn), t ) == 0;
}
/*!
\overload
Removes the file \a fileName.
Returns TRUE if successful, otherwise FALSE.
*/
bool TQFile::remove( const TQString &fileName )
{
if ( fileName.isEmpty() ) {
#if defined(QT_CHECK_NULL)
qWarning( "TQFile::remove: Empty or null file name" );
#endif
return FALSE;
}
return unlink( TQFile::encodeName(fileName) ) == 0;
}
#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 \a m. Returns TRUE if successful, otherwise FALSE.
\keyword IO_Raw
\keyword IO_ReadOnly
\keyword IO_WriteOnly
\keyword IO_ReadWrite
\keyword IO_Append
\keyword IO_Truncate
\keyword IO_Translate
The mode parameter \a m must be a combination of the following flags:
\table
\header \i Flag \i Meaning
\row \i IO_Raw
\i Raw (non-buffered) file access.
\row \i IO_ReadOnly
\i Opens the file in read-only mode.
\row \i IO_WriteOnly
\i Opens the file in write-only mode. If this flag is used
with another flag, e.g. \c IO_ReadOnly or \c IO_Raw or \c
IO_Append, the file is \e not truncated; but if used on
its own (or with \c IO_Truncate), the file is truncated.
\row \i IO_ReadWrite
\i Opens the file in read/write mode, equivalent to \c
(IO_ReadOnly | IO_WriteOnly).
\row \i IO_Append
\i Opens the file in append mode. (You must actually use \c
(IO_WriteOnly | IO_Append) to make the file writable and
to go into 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.
\row \i IO_Truncate
\i Truncates the file.
\row \i IO_Translate
\i Enables carriage returns and linefeed translation for text
files under Windows.
\endtable
The raw access mode is best when I/O is block-operated using a 4KB
block size or greater. Buffered access works better when reading
small portions of data at a time.
\warning When working with buffered files, data may not be written
to the file at once. Call flush() to make sure that the data is
really written.
\warning If you have a buffered file opened for both reading and
writing you must not perform an input operation immediately after
an output operation or vice versa. You should always call flush()
or a file positioning operation, e.g. at(), between input and
output operations, otherwise the buffer may contain garbage.
If the file does not exist and \c IO_WriteOnly or \c IO_ReadWrite
is specified, it is created.
Example:
\code
TQFile f1( "/tmp/data.bin" );
f1.open( IO_Raw | IO_ReadWrite );
TQFile f2( "readme.txt" );
f2.open( IO_ReadOnly | IO_Translate );
TQFile f3( "audit.log" );
f3.open( IO_WriteOnly | IO_Append );
\endcode
\sa name(), close(), isOpen(), flush()
*/
bool TQFile::open( int m )
{
if ( isOpen() ) { // file already open
#if defined(QT_CHECK_STATE)
qWarning( "TQFile::open: File already open" );
#endif
return FALSE;
}
if ( fn.isEmpty() ) { // no file name defined
#if defined(QT_CHECK_NULL)
qWarning( "TQFile::open: No file name specified" );
#endif
return FALSE;
}
init(); // reset params
setMode( m );
if ( !(isReadable() || isWritable()) ) {
#if defined(QT_CHECK_RANGE)
qWarning( "TQFile::open: File access not specified" );
#endif
return FALSE;
}
bool ok = TRUE;
struct stat st;
if ( isRaw() ) {
int oflags = O_RDONLY;
if ( isReadable() && isWritable() )
oflags = O_RDWR;
else if ( isWritable() )
oflags = O_WRONLY;
if ( flags() & IO_Append ) { // append to end of file?
if ( flags() & IO_Truncate )
oflags |= (O_CREAT | O_TRUNC);
else
oflags |= (O_APPEND | O_CREAT);
setFlags( flags() | IO_WriteOnly ); // append implies write
} else if ( isWritable() ) { // create/trunc if writable
if ( flags() & IO_Truncate )
oflags |= (O_CREAT | O_TRUNC);
else
oflags |= O_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 = qt_open( TQFile::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
TQCString 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 defined(HAS_TEXT_FILEMODE)
if ( isTranslated() )
strcat( perm2, "t" );
else
strcat( perm2, "b" );
#endif
for (;;) { // At most twice
fh = fopen( TQFile::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 & S_IFMT) != S_IFREG ) {
// non-seekable
setType( IO_Sequential );
length = INT_MAX;
ioIndex = 0;
} else {
#if defined(QT_LARGEFILE_SUPPORT) && !defined(QT_ABI_QT4)
length = st.st_size > UINT_MAX ? UINT_MAX : (Offset)st.st_size;
#else
length = (Offset)st.st_size;
#endif
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;
ioIndex = 0;
}
resetStatus();
}
}
} else {
init();
if ( errno == EMFILE ) // no more file handles/descrs
setStatus( IO_ResourceError );
else
setStatus( IO_OpenError );
setErrorStringErrno( errno );
}
return ok;
}
/*!
\overload
Opens a file in the mode \a m using an existing file handle \a f.
Returns TRUE if successful, otherwise FALSE.
Example:
\code
#include <stdio.h>
void printError( const char* msg )
{
TQFile f;
f.open( IO_WriteOnly, stderr );
f.writeBlock( msg, qstrlen(msg) ); // write to stderr
f.close();
}
\endcode
When a TQFile is opened using this function, close() does not actually
close the file, only flushes it.
\warning If \a f is \c stdin, \c stdout, \c stderr, you may not
be able to seek. See TQIODevice::isSequentialAccess() for more
information.
\sa close()
*/
bool TQFile::open( int m, FILE *f )
{
if ( isOpen() ) {
#if defined(QT_CHECK_RANGE)
qWarning( "TQFile::open: File already open" );
#endif
return FALSE;
}
init();
setMode( m &~IO_Raw );
setState( IO_Open );
fh = f;
ext_f = TRUE;
struct stat st;
::fstat( fileno(fh), &st );
#if defined(QT_LARGEFILE_SUPPORT)
#if !defined(QT_ABI_QT4)
off_t tmp = ftello( fh );
ioIndex = tmp > UINT_MAX ? UINT_MAX : (Offset)tmp;
#else
ioIndex = (Offset)ftello( fh );
#endif
#else
ioIndex = (Offset)ftell( fh );
#endif
if ( (st.st_mode & S_IFMT) != S_IFREG || f == stdin ) { //stdin is non seekable
// non-seekable
setType( IO_Sequential );
length = INT_MAX;
ioIndex = 0;
} else {
#if defined(QT_LARGEFILE_SUPPORT) && !defined(QT_ABI_QT4)
length = st.st_size > UINT_MAX ? UINT_MAX : (Offset)st.st_size;
#else
length = (Offset)st.st_size;
#endif
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;
ioIndex = 0;
}
resetStatus();
}
}
return TRUE;
}
/*!
\overload
Opens a file in the mode \a m using an existing file descriptor \a f.
Returns TRUE if successful, otherwise FALSE.
When a TQFile is opened using this function, close() does not actually
close the file.
The TQFile that is opened using this function, is automatically set to be in
raw mode; this means that the file input/output functions are slow. If you
run into performance issues, you should try to use one of the other open
functions.
\warning If \a 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 TQFile::open( int m, int f )
{
if ( isOpen() ) {
#if defined(QT_CHECK_RANGE)
qWarning( "TQFile::open: File already open" );
#endif
return FALSE;
}
init();
setMode( m |IO_Raw );
setState( IO_Open );
fd = f;
ext_f = TRUE;
struct stat st;
::fstat( fd, &st );
#if defined(QT_LARGEFILE_SUPPORT) && !defined(QT_ABI_QT4)
off_t tmp = ::lseek(fd, 0, SEEK_CUR);
ioIndex = tmp > UINT_MAX ? UINT_MAX : (Offset)tmp;
#else
ioIndex = (Offset)::lseek(fd, 0, SEEK_CUR);
#endif
if ( (st.st_mode & S_IFMT) != S_IFREG || f == 0 ) { // stdin is not seekable...
// non-seekable
setType( IO_Sequential );
length = INT_MAX;
ioIndex = 0;
} else {
#if defined(QT_LARGEFILE_SUPPORT) && !defined(QT_ABI_QT4)
length = st.st_size > UINT_MAX ? UINT_MAX : (Offset)st.st_size;
#else
length = (Offset)st.st_size;
#endif
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;
ioIndex = 0;
}
resetStatus();
}
}
return TRUE;
}
/*!
Returns the file size.
\sa at()
*/
TQIODevice::Offset TQFile::size() const
{
struct stat st;
int ret = 0;
if ( isOpen() ) {
ret = ::fstat( fh ? fileno(fh) : fd, &st );
} else {
ret = ::stat( TQFile::encodeName(fn), &st );
}
if ( ret == -1 )
return 0;
#if defined(QT_LARGEFILE_SUPPORT) && !defined(QT_ABI_QT4)
return (uint)st.st_size > UINT_MAX ? UINT_MAX : (Offset)st.st_size;
#else
return st.st_size;
#endif
}
/*!
\overload
Sets the file index to \a pos. Returns TRUE if successful;
otherwise returns FALSE.
Example:
\code
TQFile 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
Use \c at() without arguments to retrieve the file offset.
\warning The result is undefined if the file was open()'ed using
the \c IO_Append specifier.
\sa size(), open()
*/
bool TQFile::at( Offset pos )
{
if ( !isOpen() ) {
#if defined(QT_CHECK_STATE)
qWarning( "TQFile::at: File is not open" );
#endif
return FALSE;
}
if ( isSequentialAccess() )
return FALSE;
bool ok;
if ( isRaw() ) {
off_t l = ::lseek( fd, pos, SEEK_SET );
ok = ( l != -1 );
pos = (Offset)l;
} else { // buffered file
#if defined(QT_LARGEFILE_SUPPORT)
ok = ( ::fseeko(fh, pos, SEEK_SET) == 0 );
#else
ok = ( ::fseek(fh, pos, SEEK_SET) == 0 );
#endif
}
if ( ok )
#if defined(QT_LARGEFILE_SUPPORT) && !defined(QT_ABI_QT4)
ioIndex = pos > UINT_MAX ? UINT_MAX : (Offset)pos;
#else
ioIndex = (Offset)pos;
#endif
#if defined(QT_CHECK_RANGE)
else
#if defined(QT_ABI_QT4)
qWarning( "TQFile::at: Cannot set file position %lld", pos );
#else
qWarning( "TQFile::at: Cannot set file position %lu", pos );
#endif
#endif
return ok;
}
/*!
\reimp
\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.
*/
Q_LONG TQFile::readBlock( char *p, Q_ULONG len )
{
if ( !len ) // nothing to do
return 0;
#if defined(QT_CHECK_NULL)
if ( !p )
qWarning( "TQFile::readBlock: Null pointer error" );
#endif
#if defined(QT_CHECK_STATE)
if ( !isOpen() ) {
qWarning( "TQFile::readBlock: File not open" );
return -1;
}
if ( !isReadable() ) {
qWarning( "TQFile::readBlock: Read operation not permitted" );
return -1;
}
#endif
Q_ULONG nread = 0; // number of bytes read
if ( !ungetchBuffer.isEmpty() ) {
// need to add these to the returned string.
uint l = ungetchBuffer.length();
while( nread < l ) {
*p = ungetchBuffer.at( l - nread - 1 );
p++;
nread++;
}
ungetchBuffer.truncate( l - nread );
}
if ( nread < len ) {
if ( isRaw() ) { // raw file
nread += ::read( fd, p, len-nread );
if ( len && nread <= 0 ) {
nread = 0;
setStatus(IO_ReadError);
setErrorStringErrno( errno );
}
} else { // buffered file
nread += fread( p, 1, len-nread, fh );
if ( (uint)nread != len ) {
if ( ferror( fh ) || nread==0 ) {
setStatus(IO_ReadError);
setErrorString( qt_fileerr_read );
}
}
}
}
if ( !isSequentialAccess() )
ioIndex += nread;
return nread;
}
/*! \reimp
Writes \a len bytes from \a 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()
*/
Q_LONG TQFile::writeBlock( const char *p, Q_ULONG len )
{
if ( !len ) // nothing to do
return 0;
#if defined(QT_CHECK_NULL)
if ( p == 0 && len != 0 )
qWarning( "TQFile::writeBlock: Null pointer error" );
#endif
#if defined(QT_CHECK_STATE)
if ( !isOpen() ) { // file not open
qWarning( "TQFile::writeBlock: File not open" );
return -1;
}
if ( !isWritable() ) { // writing not permitted
qWarning( "TQFile::writeBlock: Write operation not permitted" );
return -1;
}
#endif
Q_ULONG nwritten; // number of bytes written
if ( isRaw() ) // raw file
nwritten = ::write( fd, (void *)p, len );
else // buffered file
nwritten = fwrite( p, 1, len, fh );
if ( nwritten != len ) { // write error
if ( errno == ENOSPC ) // disk is full
setStatus( IO_ResourceError );
else
setStatus( IO_WriteError );
setErrorStringErrno( errno );
if ( !isSequentialAccess() ) {
if ( isRaw() ) { // recalc file position
#if defined(QT_LARGEFILE_SUPPORT) && !defined(QT_ABI_QT4)
off_t tmp = ::lseek( fd, 0, SEEK_CUR );
ioIndex = tmp > UINT_MAX ? UINT_MAX : (Offset)tmp;
#else
ioIndex = (Offset)::lseek( fd, 0, SEEK_CUR );
#endif
} else {
#if defined(QT_LARGEFILE_SUPPORT)
#if !defined(QT_ABI_QT4)
off_t tmp = (Offset)::fseeko( fh, 0, SEEK_CUR );
ioIndex = tmp > UINT_MAX ? UINT_MAX : (Offset)tmp;
#else
ioIndex = (Offset)::fseeko( fh, 0, SEEK_CUR );
#endif
#else
ioIndex = (Offset)::fseek( fh, 0, SEEK_CUR );
#endif
}
}
} else {
if ( !isSequentialAccess() )
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(). On systems that use file
descriptors for sockets (ie. Unix systems, but not Windows) the handle
can be used with TQSocketNotifier as well.
If the file is not open or there is an error, handle() returns -1.
\sa TQSocketNotifier
*/
int TQFile::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 TQFile::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 );
setErrorStringErrno( errno );
}
}