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/*!

    \since 4.5

    \class QFileSystemIterator

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

    You can use QFileSystemIterator 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(), QFileSystemIterator does not support sorting.

    The QFileSystemIterator 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, QFileSystemIterator is uni-directional (i.e.,

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

    access.

    QFileSystemIterator works with all supported file engines, and is implemented

    using QAbstractFileEngineIterator.

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

*/

/*! \enum QFileSystemIterator::IteratorFlag

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

    of QFileSystemIterator.

    \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 "qfilesystemiterator.h"

#include <QDebug>

#include <QtCore/qset.h>

#include <QtCore/qstack.h>

#include <QtCore/qvariant.h>

#ifdef Q_OS_WIN

#   include <windows.h>

#   include <atlbase.h>

#else

#   include <sys/stat.h>

#   include <sys/types.h>

#   include <dirent.h>

#   include <errno.h>

#endif

QT_BEGIN_NAMESPACE

class QFileSystemIteratorPrivate

{

public:

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

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

    ~QFileSystemIteratorPrivate();

    void pushSubDirectory(const QByteArray &path);

    void advance();

    bool isAcceptable() const;

    bool shouldFollowDirectory(const QFileInfo &);

    //bool matchesFilters(const QAbstractFileEngineIterator *it) const;

    inline bool atEnd() const { return m_dirPaths.isEmpty(); }

#ifdef Q_OS_WIN

    QStack<HANDLE>   m_dirStructs;

    WIN32_FIND_DATA* m_entry;

    WIN32_FIND_DATA  m_fileSearchResult;

    bool             m_bFirstSearchResult;

#else

    QStack<DIR *> m_dirStructs;

    dirent *m_entry;

#endif

    QSet<QString> visitedLinks;

    QStack<QByteArray> m_dirPaths;

    QFileInfo fileInfo;

    QString currentFilePath;

    QFileSystemIterator::IteratorFlags iteratorFlags;

    QDir::Filters filters;

    QStringList nameFilters;

    enum { DontShowDir, ShowDotDotDir, ShowDotDir, ShowDir }

        m_currentDirShown, m_nextDirShown;

    QFileSystemIterator *q;

private:

    bool advanceHelper();  // returns true if we know we have something suitable

};

/*!

    \internal

*/

QFileSystemIteratorPrivate::QFileSystemIteratorPrivate(const QString &path,

    const QStringList &nameFilters, QDir::Filters filters,

    QFileSystemIterator::IteratorFlags flags)

  : iteratorFlags(flags)

{

    if (filters == QDir::NoFilter)

        filters = QDir::AllEntries;

    this->filters = filters;

    this->nameFilters = nameFilters;

    fileInfo.setFile(path);

    QString dir = fileInfo.isSymLink() ? fileInfo.canonicalFilePath() : path;

    pushSubDirectory(dir.toLocal8Bit());

    // skip to acceptable entry

    while (true) {

        if (atEnd())

            return;

        if (isAcceptable())

            return;

        if (advanceHelper())

            return;

    }

}

/*!

    \internal

*/

QFileSystemIteratorPrivate::~QFileSystemIteratorPrivate()

{

#ifdef Q_OS_WIN

    while (!m_dirStructs.isEmpty())

        ::FindClose(m_dirStructs.pop());

#else

    while (!m_dirStructs.isEmpty())

        ::closedir(m_dirStructs.pop());

#endif

}

#ifdef Q_OS_WIN

static bool isDotOrDotDot(const wchar_t* name)

{

    if (name[0] == L'.' && name[1] == 0)

        return true;

    if (name[0] == L'.' && name[1] == L'.' && name[2] == 0)

        return true;

    return false;

}

#else

static bool isDotOrDotDot(const char *name)

{

    if (name[0] == '.' && name[1] == 0)

        return true;

    if (name[0] == '.' && name[1] == '.' && name[2] == 0)

        return true;

    return false;

}

#endif

/*!

    \internal

*/

void QFileSystemIteratorPrivate::pushSubDirectory(const QByteArray &path)

{

/*

    if (iteratorFlags & QFileSystemIterator::FollowSymlinks) {

        if (fileInfo.filePath() != path)

            fileInfo.setFile(path);

        if (fileInfo.isSymLink()) {

            visitedLinks << fileInfo.canonicalFilePath();

        } else {

            visitedLinks << fileInfo.absoluteFilePath();

        }

    }

*/

#ifdef Q_OS_WIN

    wchar_t szSearchPath[MAX_PATH];

    wcscpy(szSearchPath, QString(path).utf16());

    wcscat(szSearchPath, L"\\*");

    HANDLE dir = FindFirstFile(szSearchPath, &m_fileSearchResult);

    m_bFirstSearchResult = true;

#else

    DIR *dir = ::opendir(path.constData());

    //m_entry = ::readdir(dir);

    //while (m_entry && isDotOrDotDot(m_entry->d_name))

    //    m_entry = ::readdir(m_dirStructs.top());

#endif

    m_dirStructs.append(dir);

    m_dirPaths.append(path);

    m_entry = 0;

    if (filters & QDir::Dirs)

        m_nextDirShown = ShowDir;

    else

        m_nextDirShown = DontShowDir;

    m_currentDirShown = DontShowDir;

}

/*!

    \internal

*/

bool QFileSystemIteratorPrivate::isAcceptable() const

{

    if (!m_entry)

        return false;

    return true;

}

/*!

    \internal

*/

void QFileSystemIteratorPrivate::advance()

{

    while (true) {

        if (advanceHelper())

            return;

        if (atEnd())

            return;

        if (isAcceptable())

            return;

    }

}

bool QFileSystemIteratorPrivate::advanceHelper()

{

    if (m_dirStructs.isEmpty())

        return true;

    //printf("ADV %d %d\n", int(m_currentDirShown), int(m_nextDirShown));

    if ((filters & QDir::Dirs)) {

        m_currentDirShown = m_nextDirShown;

        if (m_nextDirShown == ShowDir) {

            //printf("RESTING ON DIR %s %x\n", m_dirPaths.top().constData(), int(filters));

            m_nextDirShown = (filters & QDir::NoDotAndDotDot) ? DontShowDir : ShowDotDir;

            // skip start directory itself

            if (m_dirStructs.size() == 1 && m_currentDirShown == ShowDir)

                return advanceHelper();

            return true;

        }

        if (m_nextDirShown == ShowDotDir) {

            //printf("RESTING ON DOT %s %x\n", m_dirPaths.top().constData(), int(filters));

            m_nextDirShown = ShowDotDotDir;

            return true;

        }

        if (m_nextDirShown == ShowDotDotDir) {

            //printf("RESTING ON DOTDOT %s %x\n", m_dirPaths.top().constData(), int(filters));

            m_nextDirShown = DontShowDir;

            return true;

        }

        m_currentDirShown = DontShowDir;

    }

#ifdef Q_OS_WIN

    m_entry = &m_fileSearchResult;

    if (m_bFirstSearchResult) {

        m_bFirstSearchResult = false;

    } else {

        if (!FindNextFile(m_dirStructs.top(), m_entry))

            m_entry = 0;

    }

    while (m_entry && isDotOrDotDot(m_entry->cFileName))

        if (!FindNextFile(m_dirStructs.top(), m_entry))

            m_entry = 0;

    if (!m_entry) {

        m_dirPaths.pop();

        FindClose(m_dirStructs.pop());

        return false;

    }

    if (m_entry->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {

        QByteArray ba = m_dirPaths.top();

        ba += '\\';

        ba += QString::fromWCharArray(m_entry->cFileName);

        pushSubDirectory(ba);

    }

#else

    m_entry = ::readdir(m_dirStructs.top());

    while (m_entry && isDotOrDotDot(m_entry->d_name))

        m_entry = ::readdir(m_dirStructs.top());

        //return false; // further iteration possibly needed

    //printf("READ %p %s\n", m_entry, m_entry ? m_entry->d_name : "");

    if (!m_entry) {

        m_dirPaths.pop();

        DIR *dir = m_dirStructs.pop();

        ::closedir(dir);

        return false; // further iteration possibly needed

    }

    const char *name = m_entry->d_name;

    QByteArray ba = m_dirPaths.top();

    ba += '/';

    ba += name;

    struct stat st;

    lstat(ba.constData(), &st);

    if (S_ISDIR(st.st_mode)) {

        pushSubDirectory(ba);

        return false; // further iteration possibly needed

    }

#endif

    return false; // further iteration possiblye needed

}

/*!

    \internal

 */

bool QFileSystemIteratorPrivate::shouldFollowDirectory(const QFileInfo &fileInfo)

{

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

    if (!(iteratorFlags & QFileSystemIterator::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 & QFileSystemIterator::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.

*/

#if 0

bool QFileSystemIteratorPrivate::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;

}

#endif

/*!

    Constructs a QFileSystemIterator 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.

    \sa atEnd(), next(), IteratorFlags

*/

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

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

{

    d->q = this;

}

/*!

    Constructs a QFileSystemIterator 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().