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/*!

    \since 4.3

    \class QDirIterator

    \brief The QDirIterator class provides an iterator for directory entrylists.

    You can use QDirIterator to navigate entries of a directory one at a time.

    It is similar to QDir::entryList() and QDir::entryInfoList(), but because

    it lists entries one at a time instead of all at once, it scales better

    and is more suitable for large directories. It also supports listing

    directory contents recursively, and following symbolic links. Unlike

    QDir::entryList(), QDirIterator does not support sorting.

    The QDirIterator constructor takes a QDir or a directory as

    argument. After construction, the iterator is located before the first

    directory entry. Here's how to iterate over all the entries sequentially:

    \snippet doc/src/snippets/code/src_corelib_io_qdiriterator.cpp 0

    The next() function returns the path to the next directory entry and

    advances the iterator. You can also call filePath() to get the current

    file path without advancing the iterator.  The fileName() function returns

    only the name of the file, similar to how QDir::entryList() works. You can

    also call fileInfo() to get a QFileInfo for the current entry.

    Unlike Qt's container iterators, QDirIterator is uni-directional (i.e.,

    you cannot iterate directories in reverse order) and does not allow random

    access.

    QDirIterator works with all supported file engines, and is implemented

    using QAbstractFileEngineIterator.

    \sa QDir, QDir::entryList(), QAbstractFileEngineIterator

*/

/*! \enum QDirIterator::IteratorFlag

    This enum describes flags that you can combine to configure the behavior

    of QDirIterator.

    \value NoIteratorFlags The default value, representing no flags. The

    iterator will return entries for the assigned path.

    \value Subdirectories List entries inside all subdirectories as well.

    \value FollowSymlinks When combined with Subdirectories, this flag

    enables iterating through all subdirectories of the assigned path,

    following all symbolic links. Symbolic link loops (e.g., "link" => "." or

    "link" => "..") are automatically detected and ignored.

*/

#include "qdiriterator.h"

#include "qabstractfileengine.h"

#include <QtCore/qset.h>

#include <QtCore/qstack.h>

#include <QtCore/qvariant.h>

QT_BEGIN_NAMESPACE

class QDirIteratorPrivate

{

public:

    QDirIteratorPrivate(const QString &path, const QStringList &nameFilters,

                        QDir::Filters filters, QDirIterator::IteratorFlags flags);

    ~QDirIteratorPrivate();

    void pushSubDirectory(const QFileInfo &fileInfo, const QStringList &nameFilters,

                          QDir::Filters filters);

    void advance();

    bool shouldFollowDirectory(const QFileInfo &);

    bool matchesFilters(const QAbstractFileEngineIterator *it) const;

    QSet<QString> visitedLinks;

    QAbstractFileEngine *engine;

    QStack<QAbstractFileEngineIterator *> fileEngineIterators;

    QString path;

    QFileInfo nextFileInfo;

    //This fileinfo is the current that we will return from the public API

    QFileInfo currentFileInfo;

    QDirIterator::IteratorFlags iteratorFlags;

    QDir::Filters filters;

    QStringList nameFilters;

    bool followNextDir;

    bool first;

    bool done;

    QDirIterator *q;

};

/*!

    \internal

*/

QDirIteratorPrivate::QDirIteratorPrivate(const QString &path, const QStringList &nameFilters,

                                         QDir::Filters filters, QDirIterator::IteratorFlags flags)

    : engine(0), path(path), iteratorFlags(flags), followNextDir(false), first(true), done(false)

{

    if (filters == QDir::NoFilter)

        filters = QDir::AllEntries;

    this->filters = filters;

    this->nameFilters = nameFilters;

    nextFileInfo.setFile(path);

    pushSubDirectory(nextFileInfo, nameFilters, filters);

}

/*!

    \internal

*/

QDirIteratorPrivate::~QDirIteratorPrivate()

{

    delete engine;

}

/*!

    \internal

*/

void QDirIteratorPrivate::pushSubDirectory(const QFileInfo &fileInfo, const QStringList &nameFilters,

                                           QDir::Filters filters)

{

    QString path = fileInfo.filePath();

#ifdef Q_OS_WIN

    if (fileInfo.isSymLink())

        path = fileInfo.canonicalFilePath();

#endif

    if (iteratorFlags & QDirIterator::FollowSymlinks)

        visitedLinks << fileInfo.canonicalFilePath();

    if (engine || (engine = QAbstractFileEngine::create(this->path))) {

        engine->setFileName(path);

        QAbstractFileEngineIterator *it = engine->beginEntryList(filters, nameFilters);

        if (it) {

            it->setPath(path);

            fileEngineIterators << it;

        } else {

            // No iterator; no entry list.

        }

    }

}

/*!

    \internal

*/

void QDirIteratorPrivate::advance()

{

    // Advance to the next entry

    if (followNextDir) {

        // Start by navigating into the current directory.

        QAbstractFileEngineIterator *it = fileEngineIterators.top();

        pushSubDirectory(it->currentFileInfo(), it->nameFilters(), it->filters());

        followNextDir = false;

    }

    while (!fileEngineIterators.isEmpty()) {

        QAbstractFileEngineIterator *it = fileEngineIterators.top();

        // Find the next valid iterator that matches the filters.

        bool foundDirectory = false;

        while (it->hasNext()) {

            it->next();

            if (matchesFilters(it)) {

                currentFileInfo = nextFileInfo;

                nextFileInfo = it->currentFileInfo();

                // Signal that we want to follow this entry.

                followNextDir = shouldFollowDirectory(nextFileInfo);

                //We found a matching entry.

                return;

            } else if (shouldFollowDirectory(it->currentFileInfo())) {

                pushSubDirectory(it->currentFileInfo(), it->nameFilters(), it->filters());

                foundDirectory = true;

                break;

            }

        }

        if (!foundDirectory)

            delete fileEngineIterators.pop();

    }

    currentFileInfo = nextFileInfo;

    done = true;

}

/*!

    \internal

 */

bool QDirIteratorPrivate::shouldFollowDirectory(const QFileInfo &fileInfo)

{

    // If we're doing flat iteration, we're done.

    if (!(iteratorFlags & QDirIterator::Subdirectories))

        return false;

    // Never follow non-directory entries

    if (!fileInfo.isDir())

        return false;

    // Never follow . and ..

    if (fileInfo.fileName() == QLatin1String(".") || fileInfo.fileName() == QLatin1String(".."))

        return false;

    // Check symlinks

    if (fileInfo.isSymLink() && !(iteratorFlags & QDirIterator::FollowSymlinks)) {

        // Follow symlinks only if FollowSymlinks was passed

        return false;

    }

    // Stop link loops

    if (visitedLinks.contains(fileInfo.canonicalFilePath()))

        return false;

    return true;

}

/*!

    \internal

    This convenience function implements the iterator's filtering logics and

    applies then to the current directory entry.

    It returns true if the current entry matches the filters (i.e., the

    current entry will be returned as part of the directory iteration);

    otherwise, false is returned.

*/

bool QDirIteratorPrivate::matchesFilters(const QAbstractFileEngineIterator *it) const

{

    const bool filterPermissions = ((filters & QDir::PermissionMask)

                                    && (filters & QDir::PermissionMask) != QDir::PermissionMask);

    const bool skipDirs     = !(filters & (QDir::Dirs | QDir::AllDirs));

    const bool skipFiles    = !(filters & QDir::Files);

    const bool skipSymlinks = (filters & QDir::NoSymLinks);

    const bool doReadable   = !filterPermissions || (filters & QDir::Readable);

    const bool doWritable   = !filterPermissions || (filters & QDir::Writable);

    const bool doExecutable = !filterPermissions || (filters & QDir::Executable);

    const bool includeHidden = (filters & QDir::Hidden);

    const bool includeSystem = (filters & QDir::System);

#ifndef QT_NO_REGEXP

    // Prepare name filters

    QList<QRegExp> regexps;

    bool hasNameFilters = !nameFilters.isEmpty() && !(nameFilters.contains(QLatin1String("*")));

    if (hasNameFilters) {

        for (int i = 0; i < nameFilters.size(); ++i) {

            regexps << QRegExp(nameFilters.at(i),

                               (filters & QDir::CaseSensitive) ? Qt::CaseSensitive : Qt::CaseInsensitive,

                               QRegExp::Wildcard);

        }

    }

#endif

    QString fileName = it->currentFileName();

    if (fileName.isEmpty()) {

        // invalid entry

        return false;

    }

    QFileInfo fi = it->currentFileInfo();

    QString filePath = it->currentFilePath();

#ifndef QT_NO_REGEXP

    // Pass all entries through name filters, except dirs if the AllDirs

    // filter is passed.

    if (hasNameFilters && !((filters & QDir::AllDirs) && fi.isDir())) {

        bool matched = false;

        for (int i = 0; i < regexps.size(); ++i) {

            if (regexps.at(i).exactMatch(fileName)) {

                matched = true;

                break;

            }

        }

        if (!matched)

            return false;

    }

#endif

    bool dotOrDotDot = (fileName == QLatin1String(".") || fileName == QLatin1String(".."));

    if ((filters & QDir::NoDotAndDotDot) && dotOrDotDot)

        return false;

    bool isHidden = !dotOrDotDot && fi.isHidden();

    if (!includeHidden && isHidden)

        return false;

    bool isSystem = (!fi.isFile() && !fi.isDir() && !fi.isSymLink())

                    || (!fi.exists() && fi.isSymLink());

    if (!includeSystem && isSystem)

        return false;

    bool alwaysShow = (filters & QDir::TypeMask) == 0

        && ((isHidden && includeHidden)

            || (includeSystem && isSystem));

    // Skip files and directories

    if ((filters & QDir::AllDirs) == 0 && skipDirs && fi.isDir()) {

        if (!alwaysShow)

            return false;

    }

    if ((skipFiles && (fi.isFile() || !fi.exists()))

        || (skipSymlinks && fi.isSymLink())) {

        if (!alwaysShow)

            return false;

    }

    if (filterPermissions

        && ((doReadable && !fi.isReadable())

            || (doWritable && !fi.isWritable())

            || (doExecutable && !fi.isExecutable()))) {

        return false;

    }

    if (!includeSystem && !dotOrDotDot && ((fi.exists() && !fi.isFile() && !fi.isDir() && !fi.isSymLink())

                                           || (!fi.exists() && fi.isSymLink()))) {

        return false;

    }

    return true;

}

/*!

    Constructs a QDirIterator that can iterate over \a dir's entrylist, using

    \a dir's name filters and regular filters. You can pass options via \a

    flags to decide how the directory should be iterated.

    By default, \a flags is NoIteratorFlags, which provides the same behavior

    as in QDir::entryList().

    The sorting in \a dir is ignored.

    \note To list symlinks that point to non existing files, QDir::System must be

     passed to the flags.

    \sa hasNext(), next(), IteratorFlags

*/

QDirIterator::QDirIterator(const QDir &dir, IteratorFlags flags)

    : d(new QDirIteratorPrivate(dir.path(), dir.nameFilters(), dir.filter(), flags))

{

    d->q = this;

}

/*!

    Constructs a QDirIterator that can iterate over \a path, with no name

    filtering and \a filters for entry filtering. You can pass options via \a

    flags to decide how the directory should be iterated.

    By default, \a filters is QDir::NoFilter, and \a flags is NoIteratorFlags,

    which provides the same behavior as in QDir::entryList().

    \note To list symlinks that point to non existing files, QDir::System must be

     passed to the flags.

    \warning This constructor expects \a flags to be left at its default value. Use

             the constructors that do not take the \a filters argument instead.

    \sa hasNext(), next(), IteratorFlags

*/

QDirIterator::QDirIterator(const QString &path, QDir::Filters filters, IteratorFlags flags)

    : d(new QDirIteratorPrivate(path, QStringList(QLatin1String("*")), filters, flags))

{

    d->q = this;

}

/*!

    Constructs a QDirIterator that can iterate over \a path. You can pass

    options via \a flags to decide how the directory should be iterated.

    By default, \a flags is NoIteratorFlags, which provides the same behavior

    as in QDir::entryList().

    \note To list symlinks that point to non existing files, QDir::System must be

     passed to the flags.

    \sa hasNext(), next(), IteratorFlags

*/

QDirIterator::QDirIterator(const QString &path, IteratorFlags flags)

    : d(new QDirIteratorPrivate(path, QStringList(QLatin1String("*")), QDir::NoFilter, flags))

{

    d->q = this;

}

/*!

    Constructs a QDirIterator that can iterate over \a path, using \a

    nameFilters and \a filters. You can pass options via \a flags to decide

    how the directory should be iterated.

    By default, \a flags is NoIteratorFlags, which provides the same behavior

    as QDir::entryList().

    \note To list symlinks that point to non existing files, QDir::System must be

     passed to the flags.

    \warning This constructor expects \c flags to be left at its default value. Use the

             constructors that do not take the \a filters argument instead.

    \sa hasNext(), next(), IteratorFlags

*/

QDirIterator::QDirIterator(const QString &path, const QStringList &nameFilters,

                           QDir::Filters filters, IteratorFlags flags)

    : d(new QDirIteratorPrivate(path, nameFilters, filters, flags))

{

    d->q = this;

}

/*!

    Destroys the QDirIterator.

*/

QDirIterator::~QDirIterator()

{

    qDeleteAll(d->fileEngineIterators);

    delete d;

}

/*!

    Advances the iterator to the next entry, and returns the file path of this

    new entry. If hasNext() returns false, this function does nothing, and

    returns a null QString.

    You can call fileName() or filePath() to get the current entry file name

    or path, or fileInfo() to get a QFileInfo for the current entry.

    \sa hasNext(), fileName(), filePath(), fileInfo()

*/

QString QDirIterator::next()

{

    if (!hasNext())

        return QString();

    d->advance();

    return filePath();

}

/*!

    Returns true if there is at least one more entry in the directory;

    otherwise, false is returned.

    \sa next(), fileName(), filePath(), fileInfo()

*/

bool QDirIterator::hasNext() const

{

    if (d->first) {

        d->first = false;

        d->advance();

    }

    return !d->done;

}

/*!

    Returns the file name for the current directory entry, without the path

    prepended.

    This function is convenient when iterating a single directory. When using

    the QDirIterator::Subdirectories flag, you can use filePath() to get the

    full path.

    \sa filePath(), fileInfo()

*/

QString QDirIterator::fileName() const

{

    return d->currentFileInfo.fileName();

}

/*!

    Returns the full file path for the current directory entry.

    \sa fileInfo(), fileName()

*/

QString QDirIterator::filePath() const

{

    return d->currentFileInfo.filePath();

}

/*!

    Returns a QFileInfo for the current directory entry.

    \sa filePath(), fileName()

*/

QFileInfo QDirIterator::fileInfo() const

{

    return d->currentFileInfo;

}

/*!

    Returns the base directory of the iterator.

*/

QString QDirIterator::path() const

{

    return d->path;

}

QT_END_NAMESPACE