// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qplatformdefs.h"
#include "qfileinfo.h"
#include "qglobal.h"
#include "qdir.h"
#include "qfileinfo_p.h"
#include "qdebug.h"

QT_BEGIN_NAMESPACE

using namespace Qt::StringLiterals;

QT_IMPL_METATYPE_EXTERN(QFileInfo)

QString QFileInfoPrivate::getFileName(QAbstractFileEngine::FileName name) const
{
    if (cache_enabled && !fileNames[(int)name].isNull())
        return fileNames[(int)name];

    QString ret;
    if (fileEngine == nullptr) { // local file; use the QFileSystemEngine directly
        switch (name) {
            case QAbstractFileEngine::CanonicalName:
            case QAbstractFileEngine::CanonicalPathName: {
                QFileSystemEntry entry = QFileSystemEngine::canonicalName(fileEntry, metaData);
                if (cache_enabled) { // be smart and store both
                    fileNames[QAbstractFileEngine::CanonicalName] = entry.filePath();
                    fileNames[QAbstractFileEngine::CanonicalPathName] = entry.path();
                }
                if (name == QAbstractFileEngine::CanonicalName)
                    ret = entry.filePath();
                else
                    ret = entry.path();
                break;
            }
            case QAbstractFileEngine::AbsoluteLinkTarget:
                ret = QFileSystemEngine::getLinkTarget(fileEntry, metaData).filePath();
                break;
            case QAbstractFileEngine::JunctionName:
                ret = QFileSystemEngine::getJunctionTarget(fileEntry, metaData).filePath();
                break;
            case QAbstractFileEngine::BundleName:
                ret = QFileSystemEngine::bundleName(fileEntry);
                break;
            case QAbstractFileEngine::AbsoluteName:
            case QAbstractFileEngine::AbsolutePathName: {
                QFileSystemEntry entry = QFileSystemEngine::absoluteName(fileEntry);
                if (cache_enabled) { // be smart and store both
                    fileNames[QAbstractFileEngine::AbsoluteName] = entry.filePath();
                    fileNames[QAbstractFileEngine::AbsolutePathName] = entry.path();
                }
                if (name == QAbstractFileEngine::AbsoluteName)
                    ret = entry.filePath();
                else
                    ret = entry.path();
                break;
            }
            default: break;
        }
    } else {
        ret = fileEngine->fileName(name);
    }
    if (ret.isNull())
        ret = ""_L1;
    if (cache_enabled)
        fileNames[(int)name] = ret;
    return ret;
}

QString QFileInfoPrivate::getFileOwner(QAbstractFileEngine::FileOwner own) const
{
    if (cache_enabled && !fileOwners[(int)own].isNull())
        return fileOwners[(int)own];
    QString ret;
    if (fileEngine == nullptr) {
        switch (own) {
        case QAbstractFileEngine::OwnerUser:
            ret = QFileSystemEngine::resolveUserName(fileEntry, metaData);
            break;
        case QAbstractFileEngine::OwnerGroup:
            ret = QFileSystemEngine::resolveGroupName(fileEntry, metaData);
            break;
        }
     } else {
        ret = fileEngine->owner(own);
    }
    if (ret.isNull())
        ret = ""_L1;
    if (cache_enabled)
        fileOwners[(int)own] = ret;
    return ret;
}

uint QFileInfoPrivate::getFileFlags(QAbstractFileEngine::FileFlags request) const
{
    Q_ASSERT(fileEngine); // should never be called when using the native FS
    // We split the testing into tests for for LinkType, BundleType, PermsMask
    // and the rest.
    // Tests for file permissions on Windows can be slow, especially on network
    // paths and NTFS drives.
    // In order to determine if a file is a symlink or not, we have to lstat().
    // If we're not interested in that information, we might as well avoid one
    // extra syscall. Bundle detecton on Mac can be slow, especially on network
    // paths, so we separate out that as well.

    QAbstractFileEngine::FileFlags req;
    uint cachedFlags = 0;

    if (request & (QAbstractFileEngine::FlagsMask | QAbstractFileEngine::TypesMask)) {
        if (!getCachedFlag(CachedFileFlags)) {
            req |= QAbstractFileEngine::FlagsMask;
            req |= QAbstractFileEngine::TypesMask;
            req &= (~QAbstractFileEngine::LinkType);
            req &= (~QAbstractFileEngine::BundleType);

            cachedFlags |= CachedFileFlags;
        }

        if (request & QAbstractFileEngine::LinkType) {
            if (!getCachedFlag(CachedLinkTypeFlag)) {
                req |= QAbstractFileEngine::LinkType;
                cachedFlags |= CachedLinkTypeFlag;
            }
        }

        if (request & QAbstractFileEngine::BundleType) {
            if (!getCachedFlag(CachedBundleTypeFlag)) {
                req |= QAbstractFileEngine::BundleType;
                cachedFlags |= CachedBundleTypeFlag;
            }
        }
    }

    if (request & QAbstractFileEngine::PermsMask) {
        if (!getCachedFlag(CachedPerms)) {
            req |= QAbstractFileEngine::PermsMask;
            cachedFlags |= CachedPerms;
        }
    }

    if (req) {
        if (cache_enabled)
            req &= (~QAbstractFileEngine::Refresh);
        else
            req |= QAbstractFileEngine::Refresh;

        QAbstractFileEngine::FileFlags flags = fileEngine->fileFlags(req);
        fileFlags |= uint(flags.toInt());
        setCachedFlag(cachedFlags);
    }

    return fileFlags & request.toInt();
}

QDateTime &QFileInfoPrivate::getFileTime(QAbstractFileEngine::FileTime request) const
{
    Q_ASSERT(fileEngine); // should never be called when using the native FS
    if (!cache_enabled)
        clearFlags();

    uint cf = 0;
    switch (request) {
    case QAbstractFileEngine::AccessTime:
        cf = CachedATime;
        break;
    case QAbstractFileEngine::BirthTime:
        cf = CachedBTime;
        break;
    case QAbstractFileEngine::MetadataChangeTime:
        cf = CachedMCTime;
        break;
    case QAbstractFileEngine::ModificationTime:
        cf = CachedMTime;
        break;
    }

    if (!getCachedFlag(cf)) {
        fileTimes[request] = fileEngine->fileTime(request);
        setCachedFlag(cf);
    }
    return fileTimes[request];
}

//************* QFileInfo

/*!
    \class QFileInfo
    \inmodule QtCore
    \reentrant
    \brief The QFileInfo class provides system-independent file information.

    \ingroup io
    \ingroup shared

    QFileInfo provides information about a file's name and position
    (path) in the file system, its access rights and whether it is a
    directory or symbolic link, etc. The file's size and last
    modified/read times are also available. QFileInfo can also be
    used to obtain information about a Qt \l{resource
    system}{resource}.

    A QFileInfo can point to a file with either a relative or an
    absolute file path. Absolute file paths begin with the directory
    separator "/" (or with a drive specification on Windows). Relative
    file names begin with a directory name or a file name and specify
    a path relative to the current working directory. An example of an
    absolute path is the string "/tmp/quartz". A relative path might
    look like "src/fatlib". You can use the function isRelative() to
    check whether a QFileInfo is using a relative or an absolute file
    path. You can call the function makeAbsolute() to convert a
    relative QFileInfo's path to an absolute path.

    \note Paths starting with a colon (\e{:}) are always considered
    absolute, as they denote a QResource.

    The file that the QFileInfo works on is set in the constructor or
    later with setFile(). Use exists() to see if the file exists and
    size() to get its size.

    The file's type is obtained with isFile(), isDir() and
    isSymLink(). The symLinkTarget() function provides the name of the file
    the symlink points to.

    On Unix (including \macos and iOS), the property getter functions in this
    class return the properties such as times and size of the target file, not
    the symlink, because Unix handles symlinks transparently. Opening a symlink
    using QFile effectively opens the link's target. For example:

    \snippet code/src_corelib_io_qfileinfo.cpp 0

    On Windows, shortcuts (\c .lnk files) are currently treated as symlinks. As
    on Unix systems, the property getters return the size of the targeted file,
    not the \c .lnk file itself.  This behavior is deprecated and will likely be
    removed in a future version of Qt, after which \c .lnk files will be treated
    as regular files.

    \snippet code/src_corelib_io_qfileinfo.cpp 1

    Elements of the file's name can be extracted with path() and
    fileName(). The fileName()'s parts can be extracted with
    baseName(), suffix() or completeSuffix(). QFileInfo objects to
    directories created by Qt classes will not have a trailing file
    separator. If you wish to use trailing separators in your own file
    info objects, just append one to the file name given to the constructors
    or setFile().

    The file's dates are returned by birthTime(), lastModified(), lastRead() and
    fileTime(). Information about the file's access permissions is
    obtained with isReadable(), isWritable() and isExecutable(). The
    file's ownership is available from owner(), ownerId(), group() and
    groupId(). You can examine a file's permissions and ownership in a
    single statement using the permission() function.

    \target NTFS permissions
    \note On NTFS file systems, ownership and permissions checking is
    disabled by default for performance reasons. To enable it,
    include the following line:

    \snippet ntfsp.cpp 0

    Permission checking is then turned on and off by incrementing and
    decrementing \c qt_ntfs_permission_lookup by 1.

    \snippet ntfsp.cpp 1

    \section1 Performance Issues

    Some of QFileInfo's functions query the file system, but for
    performance reasons, some functions only operate on the
    file name itself. For example: To return the absolute path of
    a relative file name, absolutePath() has to query the file system.
    The path() function, however, can work on the file name directly,
    and so it is faster.

    \note To speed up performance, QFileInfo caches information about
    the file.

    Because files can be changed by other users or programs, or
    even by other parts of the same program, there is a function that
    refreshes the file information: refresh(). If you want to switch
    off a QFileInfo's caching and force it to access the file system
    every time you request information from it call setCaching(false).
    If you want to make sure that all information is read from the
    file system, use stat().

    \sa QDir, QFile
*/

/*!
    \fn QFileInfo &QFileInfo::operator=(QFileInfo &&other)

    Move-assigns \a other to this QFileInfo instance.

    \since 5.2
*/

/*!
    \internal
*/
QFileInfo::QFileInfo(QFileInfoPrivate *p) : d_ptr(p)
{
}

/*!
    Constructs an empty QFileInfo object.

    Note that an empty QFileInfo object contain no file reference.

    \sa setFile()
*/
QFileInfo::QFileInfo() : d_ptr(new QFileInfoPrivate())
{
}

/*!
    Constructs a new QFileInfo that gives information about the given
    file. The \a file can also include an absolute or relative path.

    \sa setFile(), isRelative(), QDir::setCurrent(), QDir::isRelativePath()
*/
QFileInfo::QFileInfo(const QString &file) : d_ptr(new QFileInfoPrivate(file))
{
}

/*!
    Constructs a new QFileInfo that gives information about file \a
    file.

    If the \a file has a relative path, the QFileInfo will also have a
    relative path.

    \sa isRelative()
*/
QFileInfo::QFileInfo(const QFileDevice &file) : d_ptr(new QFileInfoPrivate(file.fileName()))
{
}

/*!
    Constructs a new QFileInfo that gives information about the given
    \a file relative to the directory \a dir.

    If \a dir has a relative path, the QFileInfo will also have a
    relative path.

    If \a file is an absolute path, then the directory specified
    by \a dir will be disregarded.

    \sa isRelative()
*/
QFileInfo::QFileInfo(const QDir &dir, const QString &file)
    : d_ptr(new QFileInfoPrivate(dir.filePath(file)))
{
}

/*!
    Constructs a new QFileInfo that is a copy of the given \a fileinfo.
*/
QFileInfo::QFileInfo(const QFileInfo &fileinfo)
    : d_ptr(fileinfo.d_ptr)
{

}

/*!
    Destroys the QFileInfo and frees its resources.
*/

QFileInfo::~QFileInfo()
{
}

/*!
    \fn bool QFileInfo::operator!=(const QFileInfo &fileinfo) const

    Returns \c true if this QFileInfo object refers to a different file
    than the one specified by \a fileinfo; otherwise returns \c false.

    \sa operator==()
*/

/*!
    Returns \c true if this QFileInfo object refers to a file in the same
    location as \a fileinfo; otherwise returns \c false.

    Note that the result of comparing two empty QFileInfo objects,
    containing no file references (file paths that do not exist or
    are empty), is undefined.

    \warning This will not compare two different symbolic links
    pointing to the same file.

    \warning Long and short file names that refer to the same file on Windows
    are treated as if they referred to different files.

    \sa operator!=()
*/
bool QFileInfo::operator==(const QFileInfo &fileinfo) const
{
    Q_D(const QFileInfo);
    // ### Qt 5: understand long and short file names on Windows
    // ### (GetFullPathName()).
    if (fileinfo.d_ptr == d_ptr)
        return true;
    if (d->isDefaultConstructed || fileinfo.d_ptr->isDefaultConstructed)
        return false;

    // Assume files are the same if path is the same
    if (d->fileEntry.filePath() == fileinfo.d_ptr->fileEntry.filePath())
        return true;

    Qt::CaseSensitivity sensitive;
    if (d->fileEngine == nullptr || fileinfo.d_ptr->fileEngine == nullptr) {
        if (d->fileEngine != fileinfo.d_ptr->fileEngine) // one is native, the other is a custom file-engine
            return false;

        sensitive = QFileSystemEngine::isCaseSensitive() ? Qt::CaseSensitive : Qt::CaseInsensitive;
    } else {
        if (d->fileEngine->caseSensitive() != fileinfo.d_ptr->fileEngine->caseSensitive())
            return false;
        sensitive = d->fileEngine->caseSensitive() ? Qt::CaseSensitive : Qt::CaseInsensitive;
    }

   // Fallback to expensive canonical path computation
   return canonicalFilePath().compare(fileinfo.canonicalFilePath(), sensitive) == 0;
}

/*!
    Makes a copy of the given \a fileinfo and assigns it to this QFileInfo.
*/
QFileInfo &QFileInfo::operator=(const QFileInfo &fileinfo)
{
    d_ptr = fileinfo.d_ptr;
    return *this;
}

/*!
    \fn void QFileInfo::swap(QFileInfo &other)
    \since 5.0

    Swaps this file info with \a other. This function is very fast and
    never fails.
*/

/*!
    Sets the file that the QFileInfo provides information about to \a
    file.

    The \a file can also include an absolute or relative file path.
    Absolute paths begin with the directory separator (e.g. "/" under
    Unix) or a drive specification (under Windows). Relative file
    names begin with a directory name or a file name and specify a
    path relative to the current directory.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 2

    \sa isRelative(), QDir::setCurrent(), QDir::isRelativePath()
*/
void QFileInfo::setFile(const QString &file)
{
    bool caching = d_ptr.constData()->cache_enabled;
    *this = QFileInfo(file);
    d_ptr->cache_enabled = caching;
}

/*!
    \overload

    Sets the file that the QFileInfo provides information about to \a
    file.

    If \a file includes a relative path, the QFileInfo will also have
    a relative path.

    \sa isRelative()
*/
void QFileInfo::setFile(const QFileDevice &file)
{
    setFile(file.fileName());
}

/*!
    \overload

    Sets the file that the QFileInfo provides information about to \a
    file in directory \a dir.

    If \a file includes a relative path, the QFileInfo will also
    have a relative path.

    \sa isRelative()
*/
void QFileInfo::setFile(const QDir &dir, const QString &file)
{
    setFile(dir.filePath(file));
}

/*!
    Returns an absolute path including the file name.

    The absolute path name consists of the full path and the file
    name. On Unix this will always begin with the root, '/',
    directory. On Windows this will always begin 'D:/' where D is a
    drive letter, except for network shares that are not mapped to a
    drive letter, in which case the path will begin '//sharename/'.
    QFileInfo will uppercase drive letters. Note that QDir does not do
    this. The code snippet below shows this.

    \snippet code/src_corelib_io_qfileinfo.cpp newstuff

    This function returns the same as filePath(), unless isRelative()
    is true. In contrast to canonicalFilePath(), symbolic links or
    redundant "." or ".." elements are not necessarily removed.

    \warning If filePath() is empty the behavior of this function
            is undefined.

    \sa filePath(), canonicalFilePath(), isRelative()
*/
QString QFileInfo::absoluteFilePath() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileName(QAbstractFileEngine::AbsoluteName);
}

/*!
    Returns the canonical path including the file name, i.e. an absolute
    path without symbolic links or redundant "." or ".." elements.

    If the file does not exist, canonicalFilePath() returns an empty
    string.

    \sa filePath(), absoluteFilePath(), dir()
*/
QString QFileInfo::canonicalFilePath() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileName(QAbstractFileEngine::CanonicalName);
}


/*!
    Returns a file's path absolute path. This doesn't include the
    file name.

    On Unix the absolute path will always begin with the root, '/',
    directory. On Windows this will always begin 'D:/' where D is a
    drive letter, except for network shares that are not mapped to a
    drive letter, in which case the path will begin '//sharename/'.

    In contrast to canonicalPath() symbolic links or redundant "." or
    ".." elements are not necessarily removed.

    \warning If filePath() is empty the behavior of this function
             is undefined.

    \sa absoluteFilePath(), path(), canonicalPath(), fileName(), isRelative()
*/
QString QFileInfo::absolutePath() const
{
    Q_D(const QFileInfo);

    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileName(QAbstractFileEngine::AbsolutePathName);
}

/*!
    Returns the file's path canonical path (excluding the file name),
    i.e. an absolute path without symbolic links or redundant "." or ".." elements.

    If the file does not exist, canonicalPath() returns an empty string.

    \sa path(), absolutePath()
*/
QString QFileInfo::canonicalPath() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileName(QAbstractFileEngine::CanonicalPathName);
}

/*!
    Returns the file's path. This doesn't include the file name.

    Note that, if this QFileInfo object is given a path ending in a
    slash, the name of the file is considered empty and this function
    will return the entire path.

    \sa filePath(), absolutePath(), canonicalPath(), dir(), fileName(), isRelative()
*/
QString QFileInfo::path() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->fileEntry.path();
}

/*!
    \fn bool QFileInfo::isAbsolute() const

    Returns \c true if the file path is absolute, otherwise returns \c false (i.e.
    the path is relative).

    \note Paths starting with a colon (\e{:}) are always considered absolute, as
    they denote a QResource.

    \sa isRelative()
*/

/*!
    Returns \c true if the file path is relative, otherwise returns \c
    false (i.e. the path is absolute). (E.g. under Unix a path is absolute
    if it begins with a "/").

    \note Paths starting with a colon (\e{:}) are always considered absolute,
    as they denote a QResource.

    \sa isAbsolute()
*/
bool QFileInfo::isRelative() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return true;
    if (d->fileEngine == nullptr)
        return d->fileEntry.isRelative();
    return d->fileEngine->isRelativePath();
}

/*!
    Converts the file's path to an absolute path if it is not already in that form.
    Returns \c true to indicate that the path was converted; otherwise returns \c false
    to indicate that the path was already absolute.

    \sa filePath(), isRelative()
*/
bool QFileInfo::makeAbsolute()
{
    if (d_ptr.constData()->isDefaultConstructed
            || !d_ptr.constData()->fileEntry.isRelative())
        return false;

    setFile(absoluteFilePath());
    return true;
}

/*!
    Returns \c true if the file exists; otherwise returns \c false.

    \note If the file is a symlink that points to a non-existing
    file, false is returned.
*/
bool QFileInfo::exists() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return false;
    if (d->fileEngine == nullptr) {
        if (!d->cache_enabled || !d->metaData.hasFlags(QFileSystemMetaData::ExistsAttribute))
            QFileSystemEngine::fillMetaData(d->fileEntry, d->metaData, QFileSystemMetaData::ExistsAttribute);
        return d->metaData.exists();
    }
    return d->getFileFlags(QAbstractFileEngine::ExistsFlag);
}

/*!
    \since 5.2

    Returns \c true if the \a file exists; otherwise returns \c false.

    \note If \a file is a symlink that points to a non-existing
    file, false is returned.

    \note Using this function is faster than using
    \c QFileInfo(file).exists() for file system access.
*/
bool QFileInfo::exists(const QString &file)
{
    if (file.isEmpty())
        return false;
    QFileSystemEntry entry(file);
    QFileSystemMetaData data;
    std::unique_ptr<QAbstractFileEngine> engine
        {QFileSystemEngine::resolveEntryAndCreateLegacyEngine(entry, data)};
    // Expensive fallback to non-QFileSystemEngine implementation
    if (engine)
        return QFileInfo(new QFileInfoPrivate(entry, data, std::move(engine))).exists();

    QFileSystemEngine::fillMetaData(entry, data, QFileSystemMetaData::ExistsAttribute);
    return data.exists();
}

/*!
    Refreshes the information about the file, i.e. reads in information
    from the file system the next time a cached property is fetched.
*/
void QFileInfo::refresh()
{
    Q_D(QFileInfo);
    d->clear();
}

/*!
    Returns the file name, including the path (which may be absolute
    or relative).

    \sa absoluteFilePath(), canonicalFilePath(), isRelative()
*/
QString QFileInfo::filePath() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->fileEntry.filePath();
}

/*!
    Returns the name of the file, excluding the path.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 3

    Note that, if this QFileInfo object is given a path ending in a
    slash, the name of the file is considered empty.

    \sa isRelative(), filePath(), baseName(), suffix()
*/
QString QFileInfo::fileName() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->fileEntry.fileName();
}

/*!
    \since 4.3
    Returns the name of the bundle.

    On \macos and iOS this returns the proper localized name for a bundle if the
    path isBundle(). On all other platforms an empty QString is returned.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 4

    \sa isBundle(), filePath(), baseName(), suffix()
*/
QString QFileInfo::bundleName() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileName(QAbstractFileEngine::BundleName);
}

/*!
    Returns the base name of the file without the path.

    The base name consists of all characters in the file up to (but
    not including) the \e first '.' character.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 5


    The base name of a file is computed equally on all platforms, independent
    of file naming conventions (e.g., ".bashrc" on Unix has an empty base
    name, and the suffix is "bashrc").

    \sa fileName(), suffix(), completeSuffix(), completeBaseName()
*/
QString QFileInfo::baseName() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->fileEntry.baseName();
}

/*!
    Returns the complete base name of the file without the path.

    The complete base name consists of all characters in the file up
    to (but not including) the \e last '.' character.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 6

    \sa fileName(), suffix(), completeSuffix(), baseName()
*/
QString QFileInfo::completeBaseName() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->fileEntry.completeBaseName();
}

/*!
    Returns the complete suffix (extension) of the file.

    The complete suffix consists of all characters in the file after
    (but not including) the first '.'.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 7

    \sa fileName(), suffix(), baseName(), completeBaseName()
*/
QString QFileInfo::completeSuffix() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->fileEntry.completeSuffix();
}

/*!
    Returns the suffix (extension) of the file.

    The suffix consists of all characters in the file after (but not
    including) the last '.'.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 8

    The suffix of a file is computed equally on all platforms, independent of
    file naming conventions (e.g., ".bashrc" on Unix has an empty base name,
    and the suffix is "bashrc").

    \sa fileName(), completeSuffix(), baseName(), completeBaseName()
*/
QString QFileInfo::suffix() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->fileEntry.suffix();
}


/*!
    Returns the path of the object's parent directory as a QDir object.

    \b{Note:} The QDir returned always corresponds to the object's
    parent directory, even if the QFileInfo represents a directory.

    For each of the following, dir() returns the QDir
    \c{"~/examples/191697"}.

    \snippet fileinfo/main.cpp 0

    For each of the following, dir() returns the QDir
    \c{"."}.

    \snippet fileinfo/main.cpp 1

    \sa absolutePath(), filePath(), fileName(), isRelative(), absoluteDir()
*/
QDir QFileInfo::dir() const
{
    Q_D(const QFileInfo);
    return QDir(d->fileEntry.path());
}

/*!
    Returns the file's absolute path as a QDir object.

    \sa dir(), filePath(), fileName(), isRelative()
*/
QDir QFileInfo::absoluteDir() const
{
    return QDir(absolutePath());
}

/*!
    Returns \c true if the user can read the file; otherwise returns \c false.

    If the file is a symlink, this function returns true if the target is
    readable (not the symlink).

    \note If the \l{NTFS permissions} check has not been enabled, the result
    on Windows will merely reflect whether the file exists.

    \sa isWritable(), isExecutable(), permission()
*/
bool QFileInfo::isReadable() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::UserReadPermission,
                [d]() { return (d->metaData.permissions() & QFile::ReadUser) != 0; },
                [d]() { return d->getFileFlags(QAbstractFileEngine::ReadUserPerm); });
}

/*!
    Returns \c true if the user can write to the file; otherwise returns \c false.

    If the file is a symlink, this function returns true if the target is
    writeable (not the symlink).

    \note If the \l{NTFS permissions} check has not been enabled, the result on
    Windows will merely reflect whether the file is marked as Read Only.

    \sa isReadable(), isExecutable(), permission()
*/
bool QFileInfo::isWritable() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::UserWritePermission,
                [d]() { return (d->metaData.permissions() & QFile::WriteUser) != 0; },
                [d]() { return d->getFileFlags(QAbstractFileEngine::WriteUserPerm); });
}

/*!
    Returns \c true if the file is executable; otherwise returns \c false.

    If the file is a symlink, this function returns true if the target is
    executable (not the symlink).

    \sa isReadable(), isWritable(), permission()
*/
bool QFileInfo::isExecutable() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::UserExecutePermission,
                [d]() { return (d->metaData.permissions() & QFile::ExeUser) != 0; },
                [d]() { return d->getFileFlags(QAbstractFileEngine::ExeUserPerm); });
}

/*!
    Returns \c true if this is a `hidden' file; otherwise returns \c false.

    \b{Note:} This function returns \c true for the special entries "." and
    ".." on Unix, even though QDir::entryList threats them as shown. And note
    that, since this function inspects the file name, on Unix it will inspect
    the name of the symlink, if this file is a symlink, not the target's name.

    On Windows, this function returns \c true if the target file is hidden (not
    the symlink).
*/
bool QFileInfo::isHidden() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::HiddenAttribute,
                [d]() { return d->metaData.isHidden(); },
                [d]() { return d->getFileFlags(QAbstractFileEngine::HiddenFlag); });
}

/*!
    \since 5.0
    Returns \c true if the file path can be used directly with native APIs.
    Returns \c false if the file is otherwise supported by a virtual file system
    inside Qt, such as \l{the Qt Resource System}.

    \b{Note:} Native paths may still require conversion of path separators
    and character encoding, depending on platform and input requirements of the
    native API.

    \sa QDir::toNativeSeparators(), QFile::encodeName(), filePath(),
    absoluteFilePath(), canonicalFilePath()
*/
bool QFileInfo::isNativePath() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return false;
    if (d->fileEngine == nullptr)
        return true;
    return d->getFileFlags(QAbstractFileEngine::LocalDiskFlag);
}

/*!
    Returns \c true if this object points to a file or to a symbolic
    link to a file. Returns \c false if the
    object points to something which isn't a file, such as a directory.

    If the file is a symlink, this function returns true if the target is a
    regular file (not the symlink).

    \sa isDir(), isSymLink(), isBundle()
*/
bool QFileInfo::isFile() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::FileType,
                [d]() { return d->metaData.isFile(); },
                [d]() { return d->getFileFlags(QAbstractFileEngine::FileType); });
}

/*!
    Returns \c true if this object points to a directory or to a symbolic
    link to a directory; otherwise returns \c false.

    If the file is a symlink, this function returns true if the target is a
    directory (not the symlink).

    \sa isFile(), isSymLink(), isBundle()
*/
bool QFileInfo::isDir() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::DirectoryType,
                [d]() { return d->metaData.isDirectory(); },
                [d]() { return d->getFileFlags(QAbstractFileEngine::DirectoryType); });
}


/*!
    \since 4.3
    Returns \c true if this object points to a bundle or to a symbolic
    link to a bundle on \macos and iOS; otherwise returns \c false.

    If the file is a symlink, this function returns true if the target is a
    bundle (not the symlink).

    \sa isDir(), isSymLink(), isFile()
*/
bool QFileInfo::isBundle() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::BundleType,
                [d]() { return d->metaData.isBundle(); },
                [d]() { return d->getFileFlags(QAbstractFileEngine::BundleType); });
}

/*!
    Returns \c true if this object points to a symbolic link, shortcut,
    or alias; otherwise returns \c false.

    Symbolic links exist on Unix (including \macos and iOS) and Windows
    and are typically created by the \c{ln -s} or \c{mklink} commands,
    respectively. Opening a symbolic link effectively opens
    the \l{symLinkTarget()}{link's target}.

    In addition, true will be returned for shortcuts (\c *.lnk files) on
    Windows, and aliases on \macos. This behavior is deprecated and will
    likely change in a future version of Qt. Opening a shortcut or alias
    will open the \c .lnk or alias file itself.

    Example:

    \snippet code/src_corelib_io_qfileinfo.cpp 9

    \note If the symlink points to a non existing file, exists() returns
     false.

    \sa isFile(), isDir(), symLinkTarget()
*/
bool QFileInfo::isSymLink() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::LegacyLinkType,
                [d]() { return d->metaData.isLegacyLink(); },
                [d]() { return d->getFileFlags(QAbstractFileEngine::LinkType); });
}

/*!
    Returns \c true if this object points to a symbolic link;
    otherwise returns \c false.

    Symbolic links exist on Unix (including \macos and iOS) and Windows
    (NTFS-symlink) and are typically created by the \c{ln -s} or \c{mklink}
    commands, respectively.

    Unix handles symlinks transparently. Opening a symbolic link effectively
    opens the \l{symLinkTarget()}{link's target}.

    In contrast to isSymLink(), false will be returned for shortcuts
    (\c *.lnk files) on Windows and aliases on \macos. Use QFileInfo::isShortcut()
    and QFileInfo::isAlias() instead.

    \note If the symlink points to a non existing file, exists() returns
    false.

    \sa isFile(), isDir(), isShortcut(), symLinkTarget()
*/

bool QFileInfo::isSymbolicLink() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
                QFileSystemMetaData::LegacyLinkType,
                [d]() { return d->metaData.isLink(); },
                [d]() { return d->getFileFlags(QAbstractFileEngine::LinkType); });
}

/*!
    Returns \c true if this object points to a shortcut;
    otherwise returns \c false.

    Shortcuts only exist on Windows and are typically \c .lnk files.
    For instance, true will be returned for shortcuts (\c *.lnk files) on
    Windows, but false will be returned on Unix (including \macos and iOS).

    The shortcut (.lnk) files are treated as regular files. Opening those will
    open the \c .lnk file itself. In order to open the file a shortcut
    references to, it must uses symLinkTarget() on a shortcut.

    \note Even if a shortcut (broken shortcut) points to a non existing file,
    isShortcut() returns true.

    \sa isFile(), isDir(), isSymbolicLink(), symLinkTarget()
*/
bool QFileInfo::isShortcut() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
            QFileSystemMetaData::LegacyLinkType,
            [d]() { return d->metaData.isLnkFile(); },
            [d]() { return d->getFileFlags(QAbstractFileEngine::LinkType); });
}

/*!
    Returns \c true if this object points to an alias;
    otherwise returns \c false.

    \since 6.4

    Aliases only exist on \macos. They are treated as regular files, so
    opening an alias will open the file itself. In order to open the file
    or directory an alias references use symLinkTarget().

    \note Even if an alias points to a non existing file,
    isAlias() returns true.

    \sa isFile(), isDir(), isSymLink(), symLinkTarget()
*/
bool QFileInfo::isAlias() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
            QFileSystemMetaData::LegacyLinkType,
            [d]() { return d->metaData.isAlias(); },
            [d]() { return d->getFileFlags(QAbstractFileEngine::LinkType); });
}

/*!
    \since 5.15

    Returns \c true if the object points to a junction;
    otherwise returns \c false.

    Junctions only exist on Windows' NTFS file system, and are typically
    created by the \c{mklink} command. They can be thought of as symlinks for
    directories, and can only be created for absolute paths on the local
    volume.
*/
bool QFileInfo::isJunction() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<bool>(
            QFileSystemMetaData::LegacyLinkType,
            [d]() { return d->metaData.isJunction(); },
            [d]() { return d->getFileFlags(QAbstractFileEngine::LinkType); });
}

/*!
    Returns \c true if the object points to a directory or to a symbolic
    link to a directory, and that directory is the root directory; otherwise
    returns \c false.
*/
bool QFileInfo::isRoot() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return false;
    if (d->fileEngine == nullptr) {
        if (d->fileEntry.isRoot()) {
#if defined(Q_OS_WIN)
            //the path is a drive root, but the drive may not exist
            //for backward compatibility, return true only if the drive exists
            if (!d->cache_enabled || !d->metaData.hasFlags(QFileSystemMetaData::ExistsAttribute))
                QFileSystemEngine::fillMetaData(d->fileEntry, d->metaData, QFileSystemMetaData::ExistsAttribute);
            return d->metaData.exists();
#else
            return true;
#endif
        }
        return false;
    }
    return d->getFileFlags(QAbstractFileEngine::RootFlag);
}

/*!
    \since 4.2

    Returns the absolute path to the file or directory a symbolic link
    points to, or an empty string if the object isn't a symbolic
    link.

    This name may not represent an existing file; it is only a string.
    QFileInfo::exists() returns \c true if the symlink points to an
    existing file.

    \sa exists(), isSymLink(), isDir(), isFile()
*/
QString QFileInfo::symLinkTarget() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileName(QAbstractFileEngine::AbsoluteLinkTarget);
}

/*!
    \since 6.2

    Resolves an NTFS junction to the path it references.

    Returns the absolute path to the directory an NTFS junction points to, or
    an empty string if the object is not an NTFS junction.

    There is no guarantee that the directory named by the NTFS junction actually
    exists.

    \sa isJunction(), isFile(), isDir(), isSymLink(), isSymbolicLink(),
        isShortcut()
*/
QString QFileInfo::junctionTarget() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileName(QAbstractFileEngine::JunctionName);
}

/*!
    Returns the owner of the file. On systems where files
    do not have owners, or if an error occurs, an empty string is
    returned.

    This function can be time consuming under Unix (in the order of
    milliseconds). On Windows, it will return an empty string unless
    the \l{NTFS permissions} check has been enabled.

    If the file is a symlink, this function returns the owner of the target
    (not the symlink).

    \sa ownerId(), group(), groupId()
*/
QString QFileInfo::owner() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileOwner(QAbstractFileEngine::OwnerUser);
}

/*!
    Returns the id of the owner of the file.

    On Windows and on systems where files do not have owners this
    function returns ((uint) -2).

    If the file is a symlink, this function returns the id of the owner of the target
    (not the symlink).

    \sa owner(), group(), groupId()
*/
uint QFileInfo::ownerId() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute(uint(-2),
                QFileSystemMetaData::UserId,
                [d]() { return d->metaData.userId(); },
                [d]() { return d->fileEngine->ownerId(QAbstractFileEngine::OwnerUser); });
}

/*!
    Returns the group of the file. On Windows, on systems where files
    do not have groups, or if an error occurs, an empty string is
    returned.

    This function can be time consuming under Unix (in the order of
    milliseconds).

    If the file is a symlink, this function returns the owning group of the
    target (not the symlink).

    \sa groupId(), owner(), ownerId()
*/
QString QFileInfo::group() const
{
    Q_D(const QFileInfo);
    if (d->isDefaultConstructed)
        return ""_L1;
    return d->getFileOwner(QAbstractFileEngine::OwnerGroup);
}

/*!
    Returns the id of the group the file belongs to.

    On Windows and on systems where files do not have groups this
    function always returns (uint) -2.

    If the file is a symlink, this function returns the id of the group owning the
    target (not the symlink).

    \sa group(), owner(), ownerId()
*/
uint QFileInfo::groupId() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute(uint(-2),
                QFileSystemMetaData::GroupId,
                [d]() { return d->metaData.groupId(); },
                [d]() { return d->fileEngine->ownerId(QAbstractFileEngine::OwnerGroup); });
}

/*!
    Tests for file permissions. The \a permissions argument can be
    several flags of type QFile::Permissions OR-ed together to check
    for permission combinations.

    On systems where files do not have permissions this function
    always returns \c true.

    \note The result might be inaccurate on Windows if the
    \l{NTFS permissions} check has not been enabled.

    Example:
    \snippet code/src_corelib_io_qfileinfo.cpp 10

    If the file is a symlink, this function checks the permissions of the
    target (not the symlink).

    \sa isReadable(), isWritable(), isExecutable()
*/
bool QFileInfo::permission(QFile::Permissions permissions) const
{
    Q_D(const QFileInfo);
    // the QFileSystemMetaData::MetaDataFlag and QFile::Permissions overlap, so just cast.
    auto fseFlags = QFileSystemMetaData::MetaDataFlags::fromInt(permissions.toInt());
    auto feFlags = QAbstractFileEngine::FileFlags::fromInt(permissions.toInt());
    return d->checkAttribute<bool>(
                fseFlags,
                [=]() { return (d->metaData.permissions() & permissions) == permissions; },
        [=]() {
            return d->getFileFlags(feFlags) == uint(permissions.toInt());
        });
}

/*!
    Returns the complete OR-ed together combination of
    QFile::Permissions for the file.

    \note The result might be inaccurate on Windows if the
    \l{NTFS permissions} check has not been enabled.

    If the file is a symlink, this function returns the permissions of the
    target (not the symlink).
*/
QFile::Permissions QFileInfo::permissions() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<QFile::Permissions>(
                QFileSystemMetaData::Permissions,
                [d]() { return d->metaData.permissions(); },
        [d]() {
            return QFile::Permissions(d->getFileFlags(QAbstractFileEngine::PermsMask) & QAbstractFileEngine::PermsMask);
        });
}


/*!
    Returns the file size in bytes. If the file does not exist or cannot be
    fetched, 0 is returned.

    If the file is a symlink, the size of the target file is returned
    (not the symlink).

    \sa exists()
*/
qint64 QFileInfo::size() const
{
    Q_D(const QFileInfo);
    return d->checkAttribute<qint64>(
                QFileSystemMetaData::SizeAttribute,
                [d]() { return d->metaData.size(); },
        [d]() {
            if (!d->getCachedFlag(QFileInfoPrivate::CachedSize)) {
                d->setCachedFlag(QFileInfoPrivate::CachedSize);
                d->fileSize = d->fileEngine->size();
            }
            return d->fileSize;
        });
}

/*!
    \fn QDateTime QFileInfo::birthTime() const
    \since 5.10
    Returns the date and time when the file was created / born.

    If the file birth time is not available, this function returns an invalid
    QDateTime.

    If the file is a symlink, the time of the target file is returned
    (not the symlink).

    \sa lastModified(), lastRead(), metadataChangeTime()
*/

/*!
    \fn QDateTime QFileInfo::metadataChangeTime() const
    \since 5.10
    Returns the date and time when the file metadata was changed. A metadata
    change occurs when the file is created, but it also occurs whenever the
    user writes or sets inode information (for example, changing the file
    permissions).

    If the file is a symlink, the time of the target file is returned
    (not the symlink).

    \sa lastModified(), lastRead()
*/

/*!
    \fn QDateTime QFileInfo::lastModified() const

    Returns the date and local time when the file was last modified.

    If the file is a symlink, the time of the target file is returned
    (not the symlink).

    \sa birthTime(), lastRead(), metadataChangeTime(), fileTime()
*/

/*!
    \fn QDateTime QFileInfo::lastRead() const

    Returns the date and local time when the file was last read (accessed).

    On platforms where this information is not available, returns the
    same as lastModified().

    If the file is a symlink, the time of the target file is returned
    (not the symlink).

    \sa birthTime(), lastModified(), metadataChangeTime(), fileTime()
*/

/*!
    \since 5.10

    Returns the file time specified by \a time. If the time cannot be
    determined, an invalid date time is returned.

    If the file is a symlink, the time of the target file is returned
    (not the symlink).

    \sa QFile::FileTime, QDateTime::isValid()
*/
QDateTime QFileInfo::fileTime(QFile::FileTime time) const
{
    static_assert(int(QFile::FileAccessTime) == int(QAbstractFileEngine::AccessTime));
    static_assert(int(QFile::FileBirthTime) == int(QAbstractFileEngine::BirthTime));
    static_assert(int(QFile::FileMetadataChangeTime) == int(QAbstractFileEngine::MetadataChangeTime));
    static_assert(int(QFile::FileModificationTime) == int(QAbstractFileEngine::ModificationTime));

    Q_D(const QFileInfo);
    auto fetime = QAbstractFileEngine::FileTime(time);
    QFileSystemMetaData::MetaDataFlags flag;
    switch (time) {
    case QFile::FileAccessTime:
        flag = QFileSystemMetaData::AccessTime;
        break;
    case QFile::FileBirthTime:
        flag = QFileSystemMetaData::BirthTime;
        break;
    case QFile::FileMetadataChangeTime:
        flag = QFileSystemMetaData::MetadataChangeTime;
        break;
    case QFile::FileModificationTime:
        flag = QFileSystemMetaData::ModificationTime;
        break;
    }

    return d->checkAttribute<QDateTime>(
                flag,
                [=]() { return d->metaData.fileTime(fetime).toLocalTime(); },
                [=]() { return d->getFileTime(fetime).toLocalTime(); });
}

/*!
    \internal
*/
QFileInfoPrivate* QFileInfo::d_func()
{
    return d_ptr.data();
}

/*!
    Returns \c true if caching is enabled; otherwise returns \c false.

    \sa setCaching(), refresh()
*/
bool QFileInfo::caching() const
{
    Q_D(const QFileInfo);
    return d->cache_enabled;
}

/*!
    If \a enable is true, enables caching of file information. If \a
    enable is false caching is disabled.

    When caching is enabled, QFileInfo reads the file information from
    the file system the first time it's needed, but generally not
    later.

    Caching is enabled by default.

    \sa refresh(), caching()
*/
void QFileInfo::setCaching(bool enable)
{
    Q_D(QFileInfo);
    d->cache_enabled = enable;
}

/*!
    Reads all attributes from the file system.
    \since 6.0

    This is useful when information about the file system is collected in a
    worker thread, and then passed to the UI in the form of caching QFileInfo
    instances.

    \sa setCaching(), refresh()
*/
void QFileInfo::stat()
{
    Q_D(QFileInfo);
    QFileSystemEngine::fillMetaData(d->fileEntry, d->metaData, QFileSystemMetaData::AllMetaDataFlags);
}

/*!
    \typedef QFileInfoList
    \relates QFileInfo

    Synonym for QList<QFileInfo>.
*/

#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug dbg, const QFileInfo &fi)
{
    QDebugStateSaver saver(dbg);
    dbg.nospace();
    dbg.noquote();
    dbg << "QFileInfo(" << QDir::toNativeSeparators(fi.filePath()) << ')';
    return dbg;
}
#endif

/*!
    \fn QFileInfo::QFileInfo(const std::filesystem::path &file)
    \since 6.0

    Constructs a new QFileInfo that gives information about the given
    \a file.

    \sa setFile(), isRelative(), QDir::setCurrent(), QDir::isRelativePath()
*/
/*!
    \fn QFileInfo::QFileInfo(const QDir &dir, const std::filesystem::path &file)
    \since 6.0

    Constructs a new QFileInfo that gives information about the given
    \a file relative to the directory \a dir.

    If \a dir has a relative path, the QFileInfo will also have a
    relative path.

    If \a file is an absolute path, then the directory specified
    by \a dir will be disregarded.
*/
/*!
    \fn void QFileInfo::setFile(const std::filesystem::path &file)
    \since 6.0

    Sets the file that the QFileInfo provides information about to \a
    file.
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemFilePath() const
    \since 6.0

    Returns filePath() as a \c{std::filesystem::path}.
    \sa filePath()
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemAbsoluteFilePath() const
    \since 6.0

    Returns absoluteFilePath() as a \c{std::filesystem::path}.
    \sa absoluteFilePath()
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemCanonicalFilePath() const
    \since 6.0

    Returns canonicalFilePath() as a \c{std::filesystem::path}.
    \sa canonicalFilePath()
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemPath() const
    \since 6.0

    Returns path() as a \c{std::filesystem::path}.
    \sa path()
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemAbsolutePath() const
    \since 6.0

    Returns absolutePath() as a \c{std::filesystem::path}.
    \sa absolutePath()
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemCanonicalPath() const
    \since 6.0

    Returns canonicalPath() as a \c{std::filesystem::path}.
    \sa canonicalPath()
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemSymLinkTarget() const
    \since 6.0

    Returns symLinkTarget() as a \c{std::filesystem::path}.
    \sa symLinkTarget()
*/
/*!
    \fn std::filesystem::path QFileInfo::filesystemJunctionTarget() const
    \since 6.2

    Returns junctionTarget() as a \c{std::filesystem::path}.
    \sa junctionTarget()
*/
/*!
    \macro QT_IMPLICIT_QFILEINFO_CONSTRUCTION
    \since 6.0
    \relates QFileInfo

    Defining this macro makes most QFileInfo constructors implicit
    instead of explicit. Since construction of QFileInfo objects is
    expensive, one should avoid accidentally creating them, especially
    if cheaper alternatives exist. For instance:

    \badcode

    QDirIterator it(dir);
    while (it.hasNext()) {
        // Implicit conversion from QString (returned by it.next()):
        // may create unnecessary data structures and cause additional
        // accesses to the file system. Unless this macro is defined,
        // this line does not compile.

        QFileInfo fi = it.next();

        ~~~
    }

    \endcode

    Instead, use the right API:

    \code

    QDirIterator it(dir);
    while (it.hasNext()) {
        // Extract the QFileInfo from the iterator directly:
        QFileInfo fi = it.nextFileInfo();

        ~~~
    }

    \endcode

    Construction from QString, QFile, and so on is always possible by
    using direct initialization instead of copy initialization:

    \code

    QFileInfo fi1 = some_string; // Does not compile unless this macro is defined
    QFileInfo fi2(some_string);  // OK
    QFileInfo fi3{some_string};  // Possibly better, avoids the risk of the Most Vexing Parse
    auto fi4 = QFileInfo(some_string); // OK

    \endcode

    This macro is provided for compatibility reason. Its usage is not
    recommended in new code.
*/

QT_END_NAMESPACE
