kdecore Library API Documentation

ksavefile.cpp

00001 /*
00002   This file is part of the KDE libraries
00003   Copyright (c) 1999 Waldo Bastian <bastian@kde.org>
00004 
00005   This library is free software; you can redistribute it and/or
00006   modify it under the terms of the GNU Library General Public
00007   License version 2 as published by the Free Software Foundation.
00008 
00009   This library is distributed in the hope that it will be useful,
00010   but WITHOUT ANY WARRANTY; without even the implied warranty of
00011   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012   Library General Public License for more details.
00013 
00014   You should have received a copy of the GNU Library General Public License
00015   along with this library; see the file COPYING.LIB.  If not, write to
00016   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
00017   Boston, MA 02111-1307, USA.
00018 */
00019 
00020 #include <config.h>
00021 
00022 #include <sys/types.h>
00023 
00024 #ifdef HAVE_SYS_STAT_H
00025 #include <sys/stat.h>
00026 #endif
00027 
00028 #include <unistd.h>
00029 #include <fcntl.h>
00030 
00031 #ifdef HAVE_TEST
00032 #include <test.h>
00033 #endif
00034 
00035 #include <qdatetime.h>
00036 #include <qdir.h>
00037 
00038 #include "kapplication.h"
00039 #include "ksavefile.h"
00040 
00041 KSaveFile::KSaveFile(const QString &filename, int mode)
00042  : mTempFile(true)
00043 {
00044 
00045    // follow symbolic link, if any
00046    QString real_filename = filename;
00047 
00048    QFileInfo file_info(real_filename);
00049    int c=0;
00050    while(file_info.isSymLink() && ++c<6) {
00051       real_filename = file_info.readLink();
00052       file_info.setFile( real_filename );
00053    }
00054 
00055    // we only check here if the directory can be written to
00056    // the actual filename isn't written to, but replaced later
00057    // with the contents of our tempfile
00058    if (!checkAccess(real_filename, W_OK))
00059    {
00060       mTempFile.setError(EACCES);
00061       return;
00062    }
00063 
00064    if (mTempFile.create(real_filename, QString::fromLatin1(".new"), mode))
00065    {
00066       mFileName = real_filename; // Set filename upon success
00067 
00068       // if we're overwriting an existing file, ensure temp file's
00069       // permissions are the same as existing file so the existing
00070       // file's permissions are preserved
00071       struct stat stat_buf;
00072       if ((stat(QFile::encodeName(real_filename), &stat_buf)==0)
00073           && (stat_buf.st_uid == getuid())
00074           && (stat_buf.st_gid == getgid()))
00075       {
00076          fchmod(mTempFile.handle() , stat_buf.st_mode);
00077       }
00078    }
00079    return;
00080 }
00081 
00082 KSaveFile::~KSaveFile()
00083 {
00084    if (mTempFile.bOpen)
00085       close(); // Close if we were still open
00086 }
00087 
00088 QString
00089 KSaveFile::name() const
00090 {
00091    return mFileName;
00092 }
00093 
00094 void
00095 KSaveFile::abort()
00096 {
00097    mTempFile.unlink();
00098    mTempFile.close();
00099 }
00100 
00101 bool
00102 KSaveFile::close()
00103 {
00104    if (mTempFile.name().isEmpty())
00105       return false; // Save was aborted already
00106    if (!mTempFile.sync())
00107    {
00108       abort();
00109       return false;
00110    }
00111    if (mTempFile.close())
00112    {
00113       QDir dir;
00114       bool result = dir.rename( mTempFile.name(), mFileName);
00115       if ( result )
00116       {
00117          return true; // Success!
00118       }
00119       mTempFile.setError(errno);
00120    }
00121 
00122    // Something went wrong, make sure to delete the interim file.
00123    mTempFile.unlink();
00124    return false;
00125 }
00126 
00127 static int
00128 write_all(int fd, const char *buf, size_t len)
00129 {
00130    while (len > 0)
00131    {
00132       int written = write(fd, buf, len);
00133       if (written < 0)
00134       {
00135           if (errno == EINTR)
00136              continue;
00137           return -1;
00138       }
00139       buf += written;
00140       len -= written;
00141    }
00142    return 0;
00143 }
00144 
00145 bool KSaveFile::backupFile( const QString& qFilename, const QString& backupDir,
00146                             const QString& backupExtension)
00147 {
00148    QCString cFilename = QFile::encodeName(qFilename);
00149    const char *filename = cFilename.data();
00150 
00151    int fd = open( filename, O_RDONLY);
00152    if (fd < 0)
00153       return false;
00154 
00155    struct stat buff;
00156    if ( fstat( fd, &buff) < 0 )
00157    {
00158       ::close( fd );
00159       return false;
00160    }
00161 
00162    QCString cBackup;
00163    if ( backupDir.isEmpty() )
00164        cBackup = cFilename;
00165    else
00166    {
00167        QCString nameOnly;
00168        int slash = cFilename.findRev('/');
00169        if (slash < 0)
00170        nameOnly = cFilename;
00171        else
00172        nameOnly = cFilename.mid(slash + 1);
00173        cBackup = QFile::encodeName(backupDir);
00174        if ( backupDir[backupDir.length()-1] != '/' )
00175            cBackup += '/';
00176        cBackup += nameOnly;
00177    }
00178    cBackup += QFile::encodeName(backupExtension);
00179    const char *backup = cBackup.data();
00180    int permissions = buff.st_mode & 07777;
00181 
00182    if ( stat( backup, &buff) == 0)
00183    {
00184       if ( unlink( backup ) != 0 )
00185       {
00186          ::close(fd);
00187          return false;
00188       }
00189    }
00190 
00191    mode_t old_umask = umask(0);
00192    int fd2 = open( backup, O_WRONLY | O_CREAT | O_EXCL, permissions | S_IWUSR);
00193    umask(old_umask);
00194 
00195    if ( fd2 < 0 )
00196    {
00197       ::close(fd);
00198       return false;
00199    }
00200 
00201     char buffer[ 32*1024 ];
00202 
00203     while( 1 )
00204     {
00205        int n = ::read( fd, buffer, 32*1024 );
00206        if (n == -1)
00207        {
00208           if (errno == EINTR)
00209               continue;
00210           ::close(fd);
00211           ::close(fd2);
00212           return false;
00213        }
00214        if (n == 0)
00215           break; // Finished
00216 
00217        if (write_all( fd2, buffer, n))
00218        {
00219           ::close(fd);
00220           ::close(fd2);
00221           return false;
00222        }
00223     }
00224 
00225     ::close( fd );
00226 
00227     if (::close(fd2))
00228         return false;
00229     return true;
00230 }
KDE Logo
This file is part of the documentation for kdecore Library Version 3.3.0.
Documentation copyright © 1996-2004 the KDE developers.
Generated on Sat Nov 27 13:41:19 2004 by doxygen 1.3.9.1 written by Dimitri van Heesch, © 1997-2003