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     2 **

     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

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     5 ** Contact: Nokia Corporation (qt-info@nokia.com)

     6 **

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    14 ** this package.

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    41 

    42 #include "qplatformdefs.h"

    43 #include "qdebug.h"

    44 #include "qfile.h"

    45 #include "qfsfileengine.h"

    46 #include "qtemporaryfile.h"

    47 #include "qlist.h"

    48 #include "qfileinfo.h"

    49 #include "private/qiodevice_p.h"

    50 #include "private/qfile_p.h"

    51 #if defined(QT_BUILD_CORE_LIB)

    52 # include "qcoreapplication.h"

    53 #endif

    54 

    55 #ifdef QT_NO_QOBJECT

    56 #define tr(X) QString::fromLatin1(X)

    57 #endif

    58 

    59 QT_BEGIN_NAMESPACE

    60 

    61 static const int QFILE_WRITEBUFFER_SIZE = 16384;

    62 

    63 static QByteArray locale_encode(const QString &f)

    64 {

    65 #ifndef Q_OS_DARWIN

    66     return f.toLocal8Bit();

    67 #else

    68     // Mac always expects UTF-8... and decomposed...

    69     return f.normalized(QString::NormalizationForm_D).toUtf8();

    70 #endif

    71 }

    72 

    73 static QString locale_decode(const QByteArray &f)

    74 {

    75 #ifndef Q_OS_DARWIN

    76     return QString::fromLocal8Bit(f);

    77 #else

    78     // Mac always gives us UTF-8 and decomposed, we want that composed...

    79     return QString::fromUtf8(f).normalized(QString::NormalizationForm_C);

    80 #endif

    81 }

    82 

    83 //************* QFilePrivate

    84 QFile::EncoderFn QFilePrivate::encoder = locale_encode;

    85 QFile::DecoderFn QFilePrivate::decoder = locale_decode;

    86 

    87 QFilePrivate::QFilePrivate()

    88     : fileEngine(0), lastWasWrite(false),

    89       writeBuffer(QFILE_WRITEBUFFER_SIZE), error(QFile::NoError)

    90 {

    91 }

    92 

    93 QFilePrivate::~QFilePrivate()

    94 {

    95     delete fileEngine;

    96     fileEngine = 0;

    97 }

    98 

    99 bool

   100 QFilePrivate::openExternalFile(int flags, int fd)

   101 {

   102 #ifdef QT_NO_FSFILEENGINE

   103     Q_UNUSED(flags);

   104     Q_UNUSED(fd);

   105     return false;

   106 #else

   107     delete fileEngine;

   108     fileEngine = 0;

   109     QFSFileEngine *fe = new QFSFileEngine;

   110     fe->setFileName(fileName);

   111     fileEngine = fe;

   112     return fe->open(QIODevice::OpenMode(flags), fd);

   113 #endif

   114 }

   115 

   116 bool

   117 QFilePrivate::openExternalFile(int flags, FILE *fh)

   118 {

   119 #ifdef QT_NO_FSFILEENGINE

   120     Q_UNUSED(flags);

   121     Q_UNUSED(fh);

   122     return false;

   123 #else

   124     delete fileEngine;

   125     fileEngine = 0;

   126     QFSFileEngine *fe = new QFSFileEngine;

   127     fe->setFileName(fileName);

   128     fileEngine = fe;

   129     return fe->open(QIODevice::OpenMode(flags), fh);

   130 #endif

   131 }

   132 

   133 inline bool QFilePrivate::ensureFlushed() const

   134 {

   135     // This function ensures that the write buffer has been flushed (const

   136     // because certain const functions need to call it.

   137     if (lastWasWrite) {

   138         const_cast<QFilePrivate *>(this)->lastWasWrite = false;

   139         if (!const_cast<QFile *>(q_func())->flush())

   140             return false;

   141     }

   142     return true;

   143 }

   144 

   145 void

   146 QFilePrivate::setError(QFile::FileError err)

   147 {

   148     error = err;

   149     errorString.clear();

   150 }

   151 

   152 void

   153 QFilePrivate::setError(QFile::FileError err, const QString &errStr)

   154 {

   155     error = err;

   156     errorString = errStr;

   157 }

   158 

   159 void

   160 QFilePrivate::setError(QFile::FileError err, int errNum)

   161 {

   162     error = err;

   163     errorString = qt_error_string(errNum);

   164 }

   165 

   166 //************* QFile

   167 

   168 /*!

   169     \class QFile

   170     \brief The QFile class provides an interface for reading from and writing to files.

   171 

   172     \ingroup io

   173 

   174     \reentrant

   175 

   176     QFile is an I/O device for reading and writing text and binary

   177     files and \l{The Qt Resource System}{resources}. A QFile may be

   178     used by itself or, more conveniently, with a QTextStream or

   179     QDataStream.

   180 

   181     The file name is usually passed in the constructor, but it can be

   182     set at any time using setFileName(). QFile expects the file

   183     separator to be '/' regardless of operating system. The use of

   184     other separators (e.g., '\\') is not supported.

   185 

   186     You can check for a file's existence using exists(), and remove a

   187     file using remove(). (More advanced file system related operations

   188     are provided by QFileInfo and QDir.)

   189 

   190     The file is opened with open(), closed with close(), and flushed

   191     with flush(). Data is usually read and written using QDataStream

   192     or QTextStream, but you can also call the QIODevice-inherited

   193     functions read(), readLine(), readAll(), write(). QFile also

   194     inherits getChar(), putChar(), and ungetChar(), which work one

   195     character at a time.

   196 

   197     The size of the file is returned by size(). You can get the

   198     current file position using pos(), or move to a new file position

   199     using seek(). If you've reached the end of the file, atEnd()

   200     returns true.

   201 

   202     \section1 Reading Files Directly

   203 

   204     The following example reads a text file line by line:

   205 

   206     \snippet doc/src/snippets/file/file.cpp 0

   207 

   208     The QIODevice::Text flag passed to open() tells Qt to convert

   209     Windows-style line terminators ("\\r\\n") into C++-style

   210     terminators ("\\n"). By default, QFile assumes binary, i.e. it

   211     doesn't perform any conversion on the bytes stored in the file.

   212 

   213     \section1 Using Streams to Read Files

   214 

   215     The next example uses QTextStream to read a text file

   216     line by line:

   217 

   218     \snippet doc/src/snippets/file/file.cpp 1

   219 

   220     QTextStream takes care of converting the 8-bit data stored on

   221     disk into a 16-bit Unicode QString. By default, it assumes that

   222     the user system's local 8-bit encoding is used (e.g., ISO 8859-1

   223     for most of Europe; see QTextCodec::codecForLocale() for

   224     details). This can be changed using setCodec().

   225 

   226     To write text, we can use operator<<(), which is overloaded to

   227     take a QTextStream on the left and various data types (including

   228     QString) on the right:

   229 

   230     \snippet doc/src/snippets/file/file.cpp 2

   231 

   232     QDataStream is similar, in that you can use operator<<() to write

   233     data and operator>>() to read it back. See the class

   234     documentation for details.

   235 

   236     When you use QFile, QFileInfo, and QDir to access the file system

   237     with Qt, you can use Unicode file names. On Unix, these file

   238     names are converted to an 8-bit encoding. If you want to use

   239     standard C++ APIs (\c <cstdio> or \c <iostream>) or

   240     platform-specific APIs to access files instead of QFile, you can

   241     use the encodeName() and decodeName() functions to convert

   242     between Unicode file names and 8-bit file names.

   243 

   244     On Unix, there are some special system files (e.g. in \c /proc) for which

   245     size() will always return 0, yet you may still be able to read more data

   246     from such a file; the data is generated in direct response to you calling

   247     read(). In this case, however, you cannot use atEnd() to determine if

   248     there is more data to read (since atEnd() will return true for a file that

   249     claims to have size 0). Instead, you should either call readAll(), or call

   250     read() or readLine() repeatedly until no more data can be read. The next

   251     example uses QTextStream to read \c /proc/modules line by line:

   252 

   253     \snippet doc/src/snippets/file/file.cpp 3

   254 

   255     \section1 Signals

   256 

   257     Unlike other QIODevice implementations, such as QTcpSocket, QFile does not

   258     emit the aboutToClose(), bytesWritten(), or readyRead() signals. This

   259     implementation detail means that QFile is not suitable for reading and

   260     writing certain types of files, such as device files on Unix platforms.

   261 

   262     \section1 Platform Specific Issues

   263 

   264     File permissions are handled differently on Linux/Mac OS X and

   265     Windows.  In a non \l{QIODevice::isWritable()}{writable}

   266     directory on Linux, files cannot be created. This is not always

   267     the case on Windows, where, for instance, the 'My Documents'

   268     directory usually is not writable, but it is still possible to

   269     create files in it.

   270 

   271     \sa QTextStream, QDataStream, QFileInfo, QDir, {The Qt Resource System}

   272 */

   273 

   274 /*!

   275     \enum QFile::FileError

   276 

   277     This enum describes the errors that may be returned by the error()

   278     function.

   279 

   280     \value NoError          No error occurred.

   281     \value ReadError        An error occurred when reading from the file.

   282     \value WriteError       An error occurred when writing to the file.

   283     \value FatalError       A fatal error occurred.

   284     \value ResourceError

   285     \value OpenError        The file could not be opened.

   286     \value AbortError       The operation was aborted.

   287     \value TimeOutError     A timeout occurred.

   288     \value UnspecifiedError An unspecified error occurred.

   289     \value RemoveError      The file could not be removed.

   290     \value RenameError      The file could not be renamed.

   291     \value PositionError    The position in the file could not be changed.

   292     \value ResizeError      The file could not be resized.

   293     \value PermissionsError The file could not be accessed.

   294     \value CopyError        The file could not be copied.

   295 

   296     \omitvalue ConnectError

   297 */

   298 

   299 /*!

   300     \enum QFile::Permission

   301 

   302     This enum is used by the permission() function to report the

   303     permissions and ownership of a file. The values may be OR-ed

   304     together to test multiple permissions and ownership values.

   305 

   306     \value ReadOwner The file is readable by the owner of the file.

   307     \value WriteOwner The file is writable by the owner of the file.

   308     \value ExeOwner The file is executable by the owner of the file.

   309     \value ReadUser The file is readable by the user.

   310     \value WriteUser The file is writable by the user.

   311     \value ExeUser The file is executable by the user.

   312     \value ReadGroup The file is readable by the group.

   313     \value WriteGroup The file is writable by the group.

   314     \value ExeGroup The file is executable by the group.

   315     \value ReadOther The file is readable by anyone.

   316     \value WriteOther The file is writable by anyone.

   317     \value ExeOther The file is executable by anyone.

   318 

   319     \warning Because of differences in the platforms supported by Qt,

   320     the semantics of ReadUser, WriteUser and ExeUser are

   321     platform-dependent: On Unix, the rights of the owner of the file

   322     are returned and on Windows the rights of the current user are

   323     returned. This behavior might change in a future Qt version.

   324 

   325     Note that Qt does not by default check for permissions on NTFS

   326     file systems, as this may decrease the performance of file

   327     handling considerably. It is possible to force permission checking

   328     on NTFS by including the following code in your source:

   329 

   330     \snippet doc/src/snippets/ntfsp.cpp 0

   331 

   332     Permission checking is then turned on and off by incrementing and

   333     decrementing \c qt_ntfs_permission_lookup by 1.

   334 

   335     \snippet doc/src/snippets/ntfsp.cpp 1

   336 */

   337 

   338 #ifdef QT3_SUPPORT

   339 /*!

   340     \typedef QFile::PermissionSpec

   341 

   342     Use QFile::Permission instead.

   343 */

   344 #endif

   345 

   346 #ifdef QT_NO_QOBJECT

   347 QFile::QFile()

   348     : QIODevice(*new QFilePrivate)

   349 {

   350 }

   351 QFile::QFile(const QString &name)

   352     : QIODevice(*new QFilePrivate)

   353 {

   354     d_func()->fileName = name;

   355 }

   356 QFile::QFile(QFilePrivate &dd)

   357     : QIODevice(dd)

   358 {

   359 }

   360 #else

   361 /*!

   362     \internal

   363 */

   364 QFile::QFile()

   365     : QIODevice(*new QFilePrivate, 0)

   366 {

   367 }

   368 /*!

   369     Constructs a new file object with the given \a parent.

   370 */

   371 QFile::QFile(QObject *parent)

   372     : QIODevice(*new QFilePrivate, parent)

   373 {

   374 }

   375 /*!

   376     Constructs a new file object to represent the file with the given \a name.

   377 */

   378 QFile::QFile(const QString &name)

   379     : QIODevice(*new QFilePrivate, 0)

   380 {

   381     Q_D(QFile);

   382     d->fileName = name;

   383 }

   384 /*!

   385     Constructs a new file object with the given \a parent to represent the

   386     file with the specified \a name.

   387 */

   388 QFile::QFile(const QString &name, QObject *parent)

   389     : QIODevice(*new QFilePrivate, parent)

   390 {

   391     Q_D(QFile);

   392     d->fileName = name;

   393 }

   394 /*!

   395     \internal

   396 */

   397 QFile::QFile(QFilePrivate &dd, QObject *parent)

   398     : QIODevice(dd, parent)

   399 {

   400 }

   401 #endif

   402 

   403 /*!

   404     Destroys the file object, closing it if necessary.

   405 */

   406 QFile::~QFile()

   407 {

   408     close();

   409 }

   410 

   411 /*!

   412     Returns the name set by setFileName() or to the QFile

   413     constructors.

   414 

   415     \sa setFileName(), QFileInfo::fileName()

   416 */

   417 QString QFile::fileName() const

   418 {

   419     return fileEngine()->fileName(QAbstractFileEngine::DefaultName);

   420 }

   421 

   422 /*!

   423     Sets the \a name of the file. The name can have no path, a

   424     relative path, or an absolute path.

   425 

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

   427 

   428     If the file name has no path or a relative path, the path used

   429     will be the application's current directory path

   430     \e{at the time of the open()} call.

   431 

   432     Example:

   433     \snippet doc/src/snippets/code/src_corelib_io_qfile.cpp 0

   434 

   435     Note that the directory separator "/" works for all operating

   436     systems supported by Qt.

   437 

   438     \sa fileName(), QFileInfo, QDir

   439 */

   440 void

   441 QFile::setFileName(const QString &name)

   442 {

   443     Q_D(QFile);

   444     if (isOpen()) {

   445         qWarning("QFile::setFileName: File (%s) is already opened",

   446                  qPrintable(fileName()));

   447         close();

   448     }

   449     if(d->fileEngine) { //get a new file engine later

   450         delete d->fileEngine;

   451         d->fileEngine = 0;

   452     }

   453     d->fileName = name;

   454 }

   455 

   456 /*!

   457     \fn QString QFile::decodeName(const char *localFileName)

   458 

   459     \overload

   460 

   461     Returns the Unicode version of the given \a localFileName. See

   462     encodeName() for details.

   463 */

   464 

   465 /*!

   466     By default, this function converts \a fileName to the local 8-bit

   467     encoding determined by the user's locale. This is sufficient for

   468     file names that the user chooses. File names hard-coded into the

   469     application should only use 7-bit ASCII filename characters.

   470 

   471     \sa decodeName() setEncodingFunction()

   472 */

   473 

   474 QByteArray

   475 QFile::encodeName(const QString &fileName)

   476 {

   477     return (*QFilePrivate::encoder)(fileName);

   478 }

   479 

   480 /*!

   481     \typedef QFile::EncoderFn

   482 

   483     This is a typedef for a pointer to a function with the following

   484     signature:

   485 

   486     \snippet doc/src/snippets/code/src_corelib_io_qfile.cpp 1

   487 

   488     \sa setEncodingFunction(), encodeName()

   489 */

   490 

   491 /*!

   492     This does the reverse of QFile::encodeName() using \a localFileName.

   493 

   494     \sa setDecodingFunction(), encodeName()

   495 */

   496 

   497 QString

   498 QFile::decodeName(const QByteArray &localFileName)

   499 {

   500     return (*QFilePrivate::decoder)(localFileName);

   501 }

   502 

   503 /*!

   504     \fn void QFile::setEncodingFunction(EncoderFn function)

   505 

   506     \nonreentrant

   507 

   508     Sets the \a function for encoding Unicode file names. The

   509     default encodes in the locale-specific 8-bit encoding.

   510 

   511     \sa encodeName(), setDecodingFunction()

   512 */

   513 

   514 void

   515 QFile::setEncodingFunction(EncoderFn f)

   516 {

   517     if (!f)

   518         f = locale_encode;

   519     QFilePrivate::encoder = f;

   520 }

   521 

   522 /*!

   523     \typedef QFile::DecoderFn

   524 

   525     This is a typedef for a pointer to a function with the following

   526     signature:

   527 

   528     \snippet doc/src/snippets/code/src_corelib_io_qfile.cpp 2

   529 

   530     \sa setDecodingFunction()

   531 */

   532 

   533 /*!

   534     \fn void QFile::setDecodingFunction(DecoderFn function)

   535 

   536     \nonreentrant

   537 

   538     Sets the \a function for decoding 8-bit file names. The

   539     default uses the locale-specific 8-bit encoding.

   540 

   541     \sa setEncodingFunction(), decodeName()

   542 */

   543 

   544 void

   545 QFile::setDecodingFunction(DecoderFn f)

   546 {

   547     if (!f)

   548         f = locale_decode;

   549     QFilePrivate::decoder = f;

   550 }

   551 

   552 /*!

   553     \overload

   554 

   555     Returns true if the file specified by fileName() exists; otherwise

   556     returns false.

   557 

   558     \sa fileName(), setFileName()

   559 */

   560 

   561 bool

   562 QFile::exists() const

   563 {

   564     // 0x1000000 = QAbstractFileEngine::Refresh, forcing an update

   565     return (fileEngine()->fileFlags(QAbstractFileEngine::FlagsMask

   566                                     | QAbstractFileEngine::FileFlag(0x1000000)) & QAbstractFileEngine::ExistsFlag);

   567 }

   568 

   569 /*!

   570     Returns true if the file specified by \a fileName exists; otherwise

   571     returns false.

   572 */

   573 

   574 bool

   575 QFile::exists(const QString &fileName)

   576 {

   577     return QFileInfo(fileName).exists();

   578 }

   579 

   580 /*!

   581     \fn QString QFile::symLinkTarget() const

   582     \since 4.2

   583     \overload

   584 

   585     Returns the absolute path of the file or directory a symlink (or shortcut

   586     on Windows) points to, or a an empty string if the object isn't a symbolic

   587     link.

   588 

   589     This name may not represent an existing file; it is only a string.

   590     QFile::exists() returns true if the symlink points to an existing file.

   591 

   592     \sa fileName() setFileName()

   593 */

   594 

   595 /*!

   596     \obsolete

   597 

   598     Use symLinkTarget() instead.

   599 */

   600 QString

   601 QFile::readLink() const

   602 {

   603     return fileEngine()->fileName(QAbstractFileEngine::LinkName);

   604 }

   605 

   606 /*!

   607     \fn static QString QFile::symLinkTarget(const QString &fileName)

   608     \since 4.2

   609 

   610     Returns the absolute path of the file or directory referred to by the

   611     symlink (or shortcut on Windows) specified by \a fileName, or returns an

   612     empty string if the \a fileName does not correspond to a symbolic link.

   613 

   614     This name may not represent an existing file; it is only a string.

   615     QFile::exists() returns true if the symlink points to an existing file.

   616 */

   617 

   618 /*!

   619     \obsolete

   620 

   621     Use symLinkTarget() instead.

   622 */

   623 QString

   624 QFile::readLink(const QString &fileName)

   625 {

   626     return QFileInfo(fileName).readLink();

   627 }

   628 

   629 /*!

   630     Removes the file specified by fileName(). Returns true if successful;

   631     otherwise returns false.

   632 

   633     The file is closed before it is removed.

   634 

   635     \sa setFileName()

   636 */

   637 

   638 bool

   639 QFile::remove()

   640 {

   641     Q_D(QFile);

   642     if (d->fileName.isEmpty()) {

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

   644         return false;

   645     }

   646     close();

   647     if(error() == QFile::NoError) {

   648         if(fileEngine()->remove()) {

   649             unsetError();

   650             return true;

   651         }

   652         d->setError(QFile::RemoveError, fileEngine()->errorString());

   653     }

   654     return false;

   655 }

   656 

   657 /*!

   658     \overload

   659 

   660     Removes the file specified by the \a fileName given.

   661 

   662     Returns true if successful; otherwise returns false.

   663 

   664     \sa remove()

   665 */

   666 

   667 bool

   668 QFile::remove(const QString &fileName)

   669 {

   670     return QFile(fileName).remove();

   671 }

   672 

   673 /*!

   674     Renames the file currently specified by fileName() to \a newName.

   675     Returns true if successful; otherwise returns false.

   676 

   677     If a file with the name \a newName already exists, rename() returns false

   678     (i.e., QFile will not overwrite it).

   679 

   680     The file is closed before it is renamed.

   681 

   682     \sa setFileName()

   683 */

   684 

   685 bool

   686 QFile::rename(const QString &newName)

   687 {

   688     Q_D(QFile);

   689     if (d->fileName.isEmpty()) {

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

   691         return false;

   692     }

   693     if (QFile(newName).exists()) {

   694         // ### Race condition. If a file is moved in after this, it /will/ be

   695         // overwritten. On Unix, the proper solution is to use hardlinks:

   696         // return ::link(old, new) && ::remove(old);

   697         d->setError(QFile::RenameError, tr("Destination file exists"));

   698         return false;

   699     }

   700     unsetError();

   701     close();

   702     if(error() == QFile::NoError) {

   703         if (fileEngine()->rename(newName)) {

   704             unsetError();

   705             // engine was able to handle the new name so we just reset it

   706             fileEngine()->setFileName(newName);

   707             d->fileName = newName;

   708             return true;

   709         }

   710 

   711         if (isSequential()) {

   712             d->setError(QFile::RenameError, tr("Will not rename sequential file using block copy"));

   713             return false;

   714         }

   715 

   716         QFile out(newName);

   717         if (open(QIODevice::ReadOnly)) {

   718             if (out.open(QIODevice::WriteOnly | QIODevice::Truncate)) {

   719                 bool error = false;

   720                 char block[4096];

   721                 qint64 bytes;

   722                 while ((bytes = read(block, sizeof(block))) > 0) {

   723                     if (bytes != out.write(block, bytes)) {

   724                         d->setError(QFile::RenameError, out.errorString());

   725                         error = true;

   726                         break;

   727                     }

   728                 }

   729                 if (bytes == -1) {

   730                     d->setError(QFile::RenameError, errorString());

   731                     error = true;

   732                 }

   733                 if(!error) {

   734                     if (!remove()) {

   735                         d->setError(QFile::RenameError, tr("Cannot remove source file"));

   736                         error = true;

   737                     }

   738                 }

   739                 if (error) {

   740                     out.remove();

   741                 } else {

   742                     fileEngine()->setFileName(newName);

   743                     setPermissions(permissions());

   744                     unsetError();

   745                     setFileName(newName);

   746                 }

   747                 close();

   748                 return !error;

   749             }

   750             close();

   751         }

   752         d->setError(QFile::RenameError, out.isOpen() ? errorString() : out.errorString());

   753     }

   754     return false;

   755 }

   756 

   757 /*!

   758     \overload

   759 

   760     Renames the file \a oldName to \a newName. Returns true if

   761     successful; otherwise returns false.

   762 

   763     If a file with the name \a newName already exists, rename() returns false

   764     (i.e., QFile will not overwrite it).

   765 

   766     \sa rename()

   767 */

   768 

   769 bool

   770 QFile::rename(const QString &oldName, const QString &newName)

   771 {

   772     return QFile(oldName).rename(newName);

   773 }

   774 

   775 /*!

   776 

   777     Creates a link named \a linkName that points to the file currently specified by

   778     fileName().  What a link is depends on the underlying filesystem (be it a

   779     shortcut on Windows or a symbolic link on Unix). Returns true if successful;

   780     otherwise returns false.

   781 

   782     This function will not overwrite an already existing entity in the file system;

   783     in this case, \c link() will return false and set \l{QFile::}{error()} to

   784     return \l{QFile::}{RenameError}.

   785 

   786     \note To create a valid link on Windows, \a linkName must have a \c{.lnk} file extension.

   787 

   788     \note On Symbian, no link is created and false is returned if fileName()

   789     currently specifies a directory.

   790 

   791     \sa setFileName()

   792 */

   793 

   794 bool

   795 QFile::link(const QString &linkName)

   796 {

   797     Q_D(QFile);

   798     if (d->fileName.isEmpty()) {

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

   800         return false;

   801     }

   802     QFileInfo fi(linkName);

   803     if(fileEngine()->link(fi.absoluteFilePath())) {

   804         unsetError();

   805         return true;

   806     }

   807     d->setError(QFile::RenameError, fileEngine()->errorString());

   808     return false;

   809 }

   810 

   811 /*!

   812     \overload

   813 

   814     Creates a link named \a linkName that points to the file \a fileName. What a link is

   815     depends on the underlying filesystem (be it a shortcut on Windows

   816     or a symbolic link on Unix). Returns true if successful; otherwise

   817     returns false.

   818 

   819     \sa link()

   820 */

   821 

   822 bool

   823 QFile::link(const QString &fileName, const QString &linkName)

   824 {

   825     return QFile(fileName).link(linkName);

   826 }

   827 

   828 /*!

   829     Copies the file currently specified by fileName() to a file called

   830     \a newName.  Returns true if successful; otherwise returns false.

   831 

   832     Note that if a file with the name \a newName already exists,

   833     copy() returns false (i.e. QFile will not overwrite it).

   834 

   835     The source file is closed before it is copied.

   836 

   837     \sa setFileName()

   838 */

   839 

   840 bool

   841 QFile::copy(const QString &newName)

   842 {

   843     Q_D(QFile);

   844     if (d->fileName.isEmpty()) {

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

   846         return false;

   847     }

   848     if (QFile(newName).exists()) {

   849         // ### Race condition. If a file is moved in after this, it /will/ be

   850         // overwritten. On Unix, the proper solution is to use hardlinks:

   851         // return ::link(old, new) && ::remove(old); See also rename().

   852         d->setError(QFile::CopyError, tr("Destination file exists"));

   853         return false;

   854     }

   855     unsetError();

   856     close();

   857     if(error() == QFile::NoError) {

   858         if(fileEngine()->copy(newName)) {

   859             unsetError();

   860             return true;

   861         } else {

   862             bool error = false;

   863             if(!open(QFile::ReadOnly)) {

   864                 error = true;

   865                 d->setError(QFile::CopyError, tr("Cannot open %1 for input").arg(d->fileName));

   866             } else {

   867                 QString fileTemplate = QLatin1String("%1/qt_temp.XXXXXX");

   868 #ifdef QT_NO_TEMPORARYFILE

   869                 QFile out(fileTemplate.arg(QFileInfo(newName).path()));

   870                 if (!out.open(QIODevice::ReadWrite))

   871                     error = true;

   872 #else

   873                 QTemporaryFile out(fileTemplate.arg(QFileInfo(newName).path()));

   874                 if (!out.open()) {

   875                     out.setFileTemplate(fileTemplate.arg(QDir::tempPath()));

   876                     if (!out.open())

   877                         error = true;

   878                 }

   879 #endif

   880                 if (error) {

   881                     out.close();

   882                     d->setError(QFile::CopyError, tr("Cannot open for output"));

   883                 } else {

   884                     char block[4096];

   885                     qint64 totalRead = 0;

   886                     while(!atEnd()) {

   887                         qint64 in = read(block, sizeof(block));

   888                         if (in <= 0)

   889                             break;

   890                         totalRead += in;

   891                         if(in != out.write(block, in)) {

   892                             d->setError(QFile::CopyError, tr("Failure to write block"));

   893                             error = true;

   894                             break;

   895                         }

   896                     }

   897 

   898                     if (totalRead != size()) {

   899                         // Unable to read from the source. The error string is

   900                         // already set from read().

   901                         error = true;

   902                     }

   903                     if (!error && !out.rename(newName)) {

   904                         error = true;

   905                         d->setError(QFile::CopyError, tr("Cannot create %1 for output").arg(newName));

   906                     }

   907 #ifdef QT_NO_TEMPORARYFILE

   908                     if (error)

   909                         out.remove();

   910 #else

   911                     if (!error)

   912                         out.setAutoRemove(false);

   913 #endif

   914                 }

   915                 close();

   916             }

   917             if(!error) {

   918                 QFile::setPermissions(newName, permissions());

   919                 unsetError();

   920                 return true;

   921             }

   922         }

   923     }

   924     return false;

   925 }

   926 

   927 /*!

   928     \overload

   929 

   930     Copies the file \a fileName to \a newName. Returns true if successful;

   931     otherwise returns false.

   932 

   933     If a file with the name \a newName already exists, copy() returns false

   934     (i.e., QFile will not overwrite it).

   935 

   936     \sa rename()

   937 */

   938 

   939 bool

   940 QFile::copy(const QString &fileName, const QString &newName)

   941 {

   942     return QFile(fileName).copy(newName);

   943 }

   944 

   945 /*!

   946     Returns true if the file can only be manipulated sequentially;

   947     otherwise returns false.

   948 

   949     Most files support random-access, but some special files may not.

   950 

   951     \sa QIODevice::isSequential()

   952 */

   953 bool QFile::isSequential() const

   954 {

   955     Q_D(const QFile);

   956     return d->fileEngine && d->fileEngine->isSequential();

   957 }

   958 

   959 /*!

   960     Opens the file using OpenMode \a mode, returning true if successful;

   961     otherwise false.

   962 

   963     The \a mode must be QIODevice::ReadOnly, QIODevice::WriteOnly, or

   964     QIODevice::ReadWrite. It may also have additional flags, such as

   965     QIODevice::Text and QIODevice::Unbuffered.

   966 

   967     \note In \l{QIODevice::}{WriteOnly} or \l{QIODevice::}{ReadWrite}

   968     mode, if the relevant file does not already exist, this function

   969     will try to create a new file before opening it.

   970 

   971     \note Because of limitations in the native API, QFile ignores the

   972     Unbuffered flag on Windows.

   973 

   974     \sa QIODevice::OpenMode, setFileName()

   975 */

   976 bool QFile::open(OpenMode mode)

   977 {

   978     Q_D(QFile);

   979     if (isOpen()) {

   980         qWarning("QFile::open: File (%s) already open", qPrintable(fileName()));

   981         return false;

   982     }

   983     if (mode & Append)

   984         mode |= WriteOnly;

   985 

   986     unsetError();

   987     if ((mode & (ReadOnly | WriteOnly)) == 0) {

   988         qWarning("QIODevice::open: File access not specified");

   989         return false;

   990     }

   991     if (fileEngine()->open(mode)) {

   992         QIODevice::open(mode);

   993         if (mode & Append)

   994             seek(size());

   995         return true;

   996     }

   997     QFile::FileError err = fileEngine()->error();

   998     if(err == QFile::UnspecifiedError)

   999         err = QFile::OpenError;

  1000     d->setError(err, fileEngine()->errorString());

  1001     return false;

  1002 }

  1003 

  1004 /*! \fn QFile::open(OpenMode, FILE*)

  1005 

  1006     Use open(FILE *, OpenMode) instead.

  1007 */

  1008 

  1009 /*!

  1010     \overload

  1011 

  1012     Opens the existing file handle \a fh in the given \a mode.

  1013     Returns true if successful; otherwise returns false.

  1014 

  1015     Example:

  1016     \snippet doc/src/snippets/code/src_corelib_io_qfile.cpp 3

  1017 

  1018     When a QFile is opened using this function, close() does not actually

  1019     close the file, but only flushes it.

  1020 

  1021     \bold{Warning:}

  1022     \list 1

  1023         \o If \a fh is \c stdin, \c stdout, or \c stderr, you may not be able

  1024            to seek(). See QIODevice::isSequential() for more information.

  1025         \o Since this function opens the file without specifying the file name,

  1026            you cannot use this QFile with a QFileInfo.

  1027     \endlist

  1028 

  1029     \note For Windows CE you may not be able to call seek() and resize().

  1030     Also, size() is set to \c 0.

  1031 

  1032     \sa close(), {qmake Variable Reference#CONFIG}{qmake Variable Reference}

  1033 

  1034     \bold{Note for the Windows Platform}

  1035 

  1036     \a fh must be opened in binary mode (i.e., the mode string must contain

  1037     'b', as in "rb" or "wb") when accessing files and other random-access

  1038     devices. Qt will translate the end-of-line characters if you pass

  1039     QIODevice::Text to \a mode. Sequential devices, such as stdin and stdout,

  1040     are unaffected by this limitation.

  1041 

  1042     You need to enable support for console applications in order to use the

  1043     stdin, stdout and stderr streams at the console. To do this, add the

  1044     following declaration to your application's project file:

  1045 

  1046     \snippet doc/src/snippets/code/src_corelib_io_qfile.cpp 4

  1047 */

  1048 bool QFile::open(FILE *fh, OpenMode mode)

  1049 {

  1050     Q_D(QFile);

  1051     if (isOpen()) {

  1052         qWarning("QFile::open: File (%s) already open", qPrintable(fileName()));

  1053         return false;

  1054     }

  1055     if (mode & Append)

  1056         mode |= WriteOnly;

  1057     unsetError();

  1058     if ((mode & (ReadOnly | WriteOnly)) == 0) {

  1059         qWarning("QFile::open: File access not specified");

  1060         return false;

  1061     }

  1062     if(d->openExternalFile(mode, fh)) {

  1063         QIODevice::open(mode);

  1064         if (mode & Append) {

  1065             seek(size());

  1066         } else {

  1067             long pos = ftell(fh);

  1068             if (pos != -1)

  1069                 seek(pos);

  1070         }

  1071         return true;

  1072     }

  1073     return false;

  1074 }

  1075 

  1076 /*! \fn QFile::open(OpenMode, int)

  1077 

  1078     Use open(int, OpenMode) instead.

  1079 */

  1080 

  1081 /*!

  1082     \overload

  1083 

  1084     Opens the existing file descripter \a fd in the given \a mode.

  1085     Returns true if successful; otherwise returns false.

  1086 

  1087     When a QFile is opened using this function, close() does not

  1088     actually close the file.

  1089 

  1090     The QFile that is opened using this function is automatically set

  1091     to be in raw mode; this means that the file input/output functions

  1092     are slow. If you run into performance issues, you should try to

  1093     use one of the other open functions.

  1094 

  1095     \warning If \a fd is 0 (\c stdin), 1 (\c stdout), or 2 (\c

  1096     stderr), you may not be able to seek(). size() is set to \c

  1097     LLONG_MAX (in \c <climits>).

  1098 

  1099     \warning For Windows CE you may not be able to call seek(), setSize(),

  1100     fileTime(). size() is set to \c 0.

  1101 

  1102     \warning Since this function opens the file without specifying the file name,

  1103              you cannot use this QFile with a QFileInfo.

  1104 

  1105     \sa close()

  1106 */

  1107 bool QFile::open(int fd, OpenMode mode)

  1108 {

  1109     Q_D(QFile);

  1110     if (isOpen()) {

  1111         qWarning("QFile::open: File (%s) already open", qPrintable(fileName()));

  1112         return false;

  1113     }

  1114     if (mode & Append)

  1115         mode |= WriteOnly;

  1116     unsetError();

  1117     if ((mode & (ReadOnly | WriteOnly)) == 0) {

  1118         qWarning("QFile::open: File access not specified");

  1119         return false;

  1120     }

  1121     if(d->openExternalFile(mode, fd)) {

  1122         QIODevice::open(mode);

  1123         if (mode & Append)

  1124             seek(size());

  1125         return true;

  1126     }

  1127     return false;

  1128 }

  1129 

  1130 /*!

  1131   Returns the file handle of the file.

  1132 

  1133   This is a small positive integer, suitable for use with C library

  1134   functions such as fdopen() and fcntl(). On systems that use file