qfsfileengine.cpp

奇趣公司比较新的qt/emd版本

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#include "qfsfileengine_p.h"
#include "qfsfileengine_iterator_p.h"
#include "qdatetime.h"
#include "qdiriterator.h"

#include <errno.h>
#include <stdio.h>

#ifdef Q_OS_WIN
#  ifndef S_ISREG
#    define S_ISREG(x)   (((x) & S_IFMT) == S_IFREG)
#  endif
#  ifndef S_ISCHR
#    define S_ISCHR(x)   (((x) & S_IFMT) == S_IFCHR)
#  endif
#  ifndef S_ISFIFO
#    define S_ISFIFO(x) false
#  endif
#  ifndef S_ISSOCK
#    define S_ISSOCK(x) false
#  endif
#  ifndef INVALID_FILE_ATTRIBUTES
#    define INVALID_FILE_ATTRIBUTES (DWORD (-1))
#  endif
#endif


/*! \class QFSFileEngine
    \brief The QFSFileEngine class implements Qt's default file engine.
    \since 4.1

    This class is part of the file engine framework in Qt. If you only want to
    access files or directories, use QFile, QFileInfo or QDir instead.

    QFSFileEngine is the default file engine for accessing regular files. It
    is provided for convenience; by subclassing this class, you can alter its
    behavior slightly, without having to write a complete QAbstractFileEngine
    subclass. To install your custom file engine, you must also subclass
    QAbstractFileEngineHandler and create an instance of your handler.

    It can also be useful to create a QFSFileEngine object directly if you
    need to use the local file system inside QAbstractFileEngine::create(), in
    order to avoid recursion (as higher-level classes tend to call
    QAbstractFileEngine::create()).
*/

//**************** QFSFileEnginePrivate
QFSFileEnginePrivate::QFSFileEnginePrivate() : QAbstractFileEnginePrivate()
{
    init();
}

/*!
    \internal
*/
void QFSFileEnginePrivate::init()
{
    is_sequential = 0;
    tried_stat = 0;
#ifdef Q_OS_UNIX
    need_lstat = 1;
    is_link = 0;
#endif
    openMode = QIODevice::NotOpen;
    fd = -1;
    fh = 0;
    lastIOCommand = IOFlushCommand;
    lastFlushFailed = false;
    closeFileHandle = false;
#ifdef Q_OS_WIN
    fileAttrib = INVALID_FILE_ATTRIBUTES;
    fileHandle = INVALID_HANDLE_VALUE;
#endif
}

/*!
    Constructs a QFSFileEngine for the file name \a file.
*/
QFSFileEngine::QFSFileEngine(const QString &file) : QAbstractFileEngine(*new QFSFileEnginePrivate)
{
    Q_D(QFSFileEngine);
    d->filePath = QDir::fromNativeSeparators(file);
    d->nativeInitFileName();
}

/*!
    Constructs a QFSFileEngine.
*/
QFSFileEngine::QFSFileEngine() : QAbstractFileEngine(*new QFSFileEnginePrivate)
{
}

/*!
    \internal
*/
QFSFileEngine::QFSFileEngine(QFSFileEnginePrivate &dd)
    : QAbstractFileEngine(dd)
{
}

/*!
    Destructs the QFSFileEngine.
*/
QFSFileEngine::~QFSFileEngine()
{
    Q_D(QFSFileEngine);
    if (d->closeFileHandle) {
        if (d->fh) {
            int ret;
            do {
                ret = fclose(d->fh);
            } while (ret == EOF && errno == EINTR);
        } else if (d->fd != -1) {
            int ret;
            do {
                ret = QT_CLOSE(d->fd);
            } while (ret == -1 && errno == EINTR);
        }
    }
}

/*!
    \reimp
*/
void QFSFileEngine::setFileName(const QString &file)
{
    Q_D(QFSFileEngine);
    d->init();
    d->filePath = QDir::fromNativeSeparators(file);
    d->nativeInitFileName();
}

/*!
    \reimp
*/
bool QFSFileEngine::open(QIODevice::OpenMode openMode)
{
    Q_D(QFSFileEngine);
    if (d->filePath.isEmpty()) {
        qWarning("QFSFileEngine::open: No file name specified");
        setError(QFile::OpenError, QLatin1String("No file name specified"));
        return false;
    }

    // Append implies WriteOnly.
    if (openMode & QFile::Append)
        openMode |= QFile::WriteOnly;

    // WriteOnly implies Truncate if neither ReadOnly nor Append are sent.
    if ((openMode & QFile::WriteOnly) && !(openMode & (QFile::ReadOnly | QFile::Append)))
        openMode |= QFile::Truncate;

    d->openMode = openMode;
    d->lastFlushFailed = false;
    d->tried_stat = 0;
    d->fh = 0;
    d->fd = -1;

    return d->nativeOpen(openMode);
}

/*!
    Opens the file handle \a fh in \a openMode mode. Returns true on
    success; otherwise returns false.
*/
bool QFSFileEngine::open(QIODevice::OpenMode openMode, FILE *fh)
{
    Q_D(QFSFileEngine);

    // Append implies WriteOnly.
    if (openMode & QFile::Append)
        openMode |= QFile::WriteOnly;

    // WriteOnly implies Truncate if neither ReadOnly nor Append are sent.
    if ((openMode & QFile::WriteOnly) && !(openMode & (QFile::ReadOnly | QFile::Append)))
        openMode |= QFile::Truncate;

    d->openMode = openMode;
    d->lastFlushFailed = false;
    d->closeFileHandle = false;
    d->nativeFilePath.clear();
    d->filePath.clear();
    d->tried_stat = 0;
    d->fd = -1;

    return d->openFh(openMode, fh);
}

/*!
    Opens the file handle \a fh using the open mode \a flags.
*/
bool QFSFileEnginePrivate::openFh(QIODevice::OpenMode openMode, FILE *fh)
{
    Q_Q(QFSFileEngine);
    this->fh = fh;
    fd = -1;

    // Seek to the end when in Append mode.
    if (openMode & QIODevice::Append) {
        int ret;
        do {
            ret = QT_FSEEK(fh, 0, SEEK_END);
        } while (ret == -1 && errno == EINTR);

        if (ret == -1) {
            q->setError(errno == EMFILE ? QFile::ResourceError : QFile::OpenError,
                        qt_error_string(int(errno)));
            return false;
        }
    }

    return true;
}

/*!
    Opens the file descriptor \a fd in \a openMode mode. Returns true
    on success; otherwise returns false.
*/
bool QFSFileEngine::open(QIODevice::OpenMode openMode, int fd)
{
    Q_D(QFSFileEngine);

    // Append implies WriteOnly.
    if (openMode & QFile::Append)
        openMode |= QFile::WriteOnly;

    // WriteOnly implies Truncate if neither ReadOnly nor Append are sent.
    if ((openMode & QFile::WriteOnly) && !(openMode & (QFile::ReadOnly | QFile::Append)))
        openMode |= QFile::Truncate;

    d->lastFlushFailed = false;
    d->closeFileHandle = false;
    d->nativeFilePath.clear();
    d->filePath.clear();
    d->fh = 0;
    d->fd = -1;
    d->tried_stat = 0;

    return d->openFd(openMode, fd);
}


/*!
    Opens the file descriptor \a fd to the file engine, using the open mode \a
    flags.
*/
bool QFSFileEnginePrivate::openFd(QIODevice::OpenMode openMode, int fd)
{
    Q_Q(QFSFileEngine);
    this->fd = fd;
    fh = 0;

    // Seek to the end when in Append mode.
    if (openMode & QFile::Append) {
        int ret;
        do {
            ret = QT_LSEEK(fd, 0, SEEK_END);
        } while (ret == -1 && errno == EINTR);

        if (ret == -1) {
            q->setError(errno == EMFILE ? QFile::ResourceError : QFile::OpenError,
                        qt_error_string(int(errno)));
            return false;
        }
    }

    return true;
}

/*!
    \reimp
*/
bool QFSFileEngine::close()
{
    Q_D(QFSFileEngine);
    d->openMode = QIODevice::NotOpen;
    return d->nativeClose();
}

/*!
    \internal
*/
bool QFSFileEnginePrivate::closeFdFh()
{
    Q_Q(QFSFileEngine);
    if (fd == -1 && !fh)
        return false;

    // Flush the file if it's buffered, and if the last flush didn't fail.
    bool flushed = !fh || (!lastFlushFailed && q->flush());
    bool closed = true;
    tried_stat = 0;

    // Close the file if we created the handle.
    if (closeFileHandle) {
        int ret;
        do {
            if (fh) {
                // Close buffered file.
                ret = fclose(fh) != 0 ? -1 : 0;
            } else {
                // Close unbuffered file.
                ret = QT_CLOSE(fd);
            }
        } while (ret == -1 && errno == EINTR);

        // We must reset these guys regardless; calling close again after a
        // failed close causes crashes on some systems.
        fh = 0;
        fd = -1;
        closed = (ret == 0);
    }

    // Report errors.
    if (!flushed || !closed) {
        if (flushed) {
            // If not flushed, we want the flush error to fall through.
            q->setError(QFile::UnspecifiedError, qt_error_string(errno));
        }
        return false;
    }

    return true;
}

/*!
    \reimp
*/
bool QFSFileEngine::flush()
{
    Q_D(QFSFileEngine);
    if ((d->openMode & QIODevice::WriteOnly) == 0) {
        // Nothing in the write buffers, so flush succeeds in doing
        // nothing.
        return true;
    }
    return d->nativeFlush();
}

/*!
    \internal
*/
bool QFSFileEnginePrivate::flushFh()
{
    Q_Q(QFSFileEngine);

    // Never try to flush again if the last flush failed. Otherwise you can
    // get crashes on some systems (AIX).
    if (lastFlushFailed)
        return false;

    int ret = fflush(fh);

    lastFlushFailed = (ret != 0);
    lastIOCommand = QFSFileEnginePrivate::IOFlushCommand;

    if (ret != 0) {