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** Copyright (C) 2016 The Qt Company Ltd.
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** This file is part of the QtCore module of the Qt Toolkit.
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** ensure the GNU Lesser General Public License version 3 requirements
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
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#include "qstandardpaths.h"
#include <qdir.h>
#include <qfile.h>
#include <qhash.h>
#include <qtextstream.h>
#if QT_CONFIG(regularexpression)
#include <qregularexpression.h>
#endif
#include <private/qfilesystemengine_p.h>
#include <errno.h>
#include <stdlib.h>

#ifndef QT_BOOTSTRAPPED
#include <qcoreapplication.h>
#endif

#ifndef QT_NO_STANDARDPATHS

QT_BEGIN_NAMESPACE

static void appendOrganizationAndApp(QString &path)
{
#ifndef QT_BOOTSTRAPPED
    const QString org = QCoreApplication::organizationName();
    if (!org.isEmpty())
        path += QLatin1Char('/') + org;
    const QString appName = QCoreApplication::applicationName();
    if (!appName.isEmpty())
        path += QLatin1Char('/') + appName;
#else
    Q_UNUSED(path);
#endif
}

#if QT_CONFIG(regularexpression)
static QLatin1String xdg_key_name(QStandardPaths::StandardLocation type)
{
    switch (type) {
    case QStandardPaths::DesktopLocation:
        return QLatin1String("DESKTOP");
    case QStandardPaths::DocumentsLocation:
        return QLatin1String("DOCUMENTS");
    case QStandardPaths::PicturesLocation:
        return QLatin1String("PICTURES");
    case QStandardPaths::MusicLocation:
        return QLatin1String("MUSIC");
    case QStandardPaths::MoviesLocation:
        return QLatin1String("VIDEOS");
    case QStandardPaths::DownloadLocation:
        return QLatin1String("DOWNLOAD");
    default:
        return QLatin1String();
    }
}
#endif

QString QStandardPaths::writableLocation(StandardLocation type)
{
    switch (type) {
    case HomeLocation:
        return QDir::homePath();
    case TempLocation:
        return QDir::tempPath();
    case CacheLocation:
    case GenericCacheLocation:
    {
        // http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html
        QString xdgCacheHome = QFile::decodeName(qgetenv("XDG_CACHE_HOME"));
        if (isTestModeEnabled())
            xdgCacheHome = QDir::homePath() + QLatin1String("/.qttest/cache");
        if (xdgCacheHome.isEmpty())
            xdgCacheHome = QDir::homePath() + QLatin1String("/.cache");
        if (type == QStandardPaths::CacheLocation)
            appendOrganizationAndApp(xdgCacheHome);
        return xdgCacheHome;
    }
    case AppDataLocation:
    case AppLocalDataLocation:
    case GenericDataLocation:
    {
        QString xdgDataHome = QFile::decodeName(qgetenv("XDG_DATA_HOME"));
        if (isTestModeEnabled())
            xdgDataHome = QDir::homePath() + QLatin1String("/.qttest/share");
        if (xdgDataHome.isEmpty())
            xdgDataHome = QDir::homePath() + QLatin1String("/.local/share");
        if (type == AppDataLocation || type == AppLocalDataLocation)
            appendOrganizationAndApp(xdgDataHome);
        return xdgDataHome;
    }
    case ConfigLocation:
    case GenericConfigLocation:
    case AppConfigLocation:
    {
        // http://standards.freedesktop.org/basedir-spec/latest/
        QString xdgConfigHome = QFile::decodeName(qgetenv("XDG_CONFIG_HOME"));
        if (isTestModeEnabled())
            xdgConfigHome = QDir::homePath() + QLatin1String("/.qttest/config");
        if (xdgConfigHome.isEmpty())
            xdgConfigHome = QDir::homePath() + QLatin1String("/.config");
        if (type == AppConfigLocation)
            appendOrganizationAndApp(xdgConfigHome);
        return xdgConfigHome;
    }
    case RuntimeLocation:
    {
        // http://standards.freedesktop.org/basedir-spec/latest/
        const uint myUid = uint(geteuid());
        // since the current user is the owner, set both xxxUser and xxxOwner
        const QFile::Permissions wantedPerms = QFile::ReadUser | QFile::WriteUser | QFile::ExeUser
                                               | QFile::ReadOwner | QFile::WriteOwner | QFile::ExeOwner;
        QFileInfo fileInfo;
        QString xdgRuntimeDir = QFile::decodeName(qgetenv("XDG_RUNTIME_DIR"));
        if (xdgRuntimeDir.isEmpty()) {
            const QString userName = QFileSystemEngine::resolveUserName(myUid);
            xdgRuntimeDir = QDir::tempPath() + QLatin1String("/runtime-") + userName;
            fileInfo.setFile(xdgRuntimeDir);
#ifndef Q_OS_WASM
            qWarning("QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '%ls'", qUtf16Printable(xdgRuntimeDir));
#endif
        } else {
            fileInfo.setFile(xdgRuntimeDir);
        }
        if (fileInfo.exists()) {
            if (!fileInfo.isDir()) {
                qWarning("QStandardPaths: XDG_RUNTIME_DIR points to '%ls' which is not a directory",
                         qUtf16Printable(xdgRuntimeDir));
                return QString();
            }
        } else {
            QFileSystemEntry entry(xdgRuntimeDir);
            if (!QFileSystemEngine::createDirectory(entry, false)) {
                if (errno != EEXIST) {
                    qErrnoWarning("QStandardPaths: error creating runtime directory %ls",
                                  qUtf16Printable(xdgRuntimeDir));
                    return QString();
                }
            } else {
                QSystemError error;
                if (!QFileSystemEngine::setPermissions(entry, wantedPerms, error)) {
                    qWarning("QStandardPaths: could not set correct permissions on runtime directory %ls: %ls",
                             qUtf16Printable(xdgRuntimeDir), qUtf16Printable(error.toString()));
                    return QString();
                }
            }
        }
        // "The directory MUST be owned by the user"
        if (fileInfo.ownerId() != myUid) {
            qWarning("QStandardPaths: wrong ownership on runtime directory %ls, %d instead of %d",
                     qUtf16Printable(xdgRuntimeDir),
                     fileInfo.ownerId(), myUid);
            return QString();
        }
        // "and he MUST be the only one having read and write access to it. Its Unix access mode MUST be 0700."
        if (fileInfo.permissions() != wantedPerms) {
            qWarning("QStandardPaths: wrong permissions on runtime directory %ls, %x instead of %x",
                     qUtf16Printable(xdgRuntimeDir), uint(fileInfo.permissions()), uint(wantedPerms));
            return QString();
        }

        return xdgRuntimeDir;
    }
    default:
        break;
    }

#if QT_CONFIG(regularexpression)
    // http://www.freedesktop.org/wiki/Software/xdg-user-dirs
    QString xdgConfigHome = QFile::decodeName(qgetenv("XDG_CONFIG_HOME"));
    if (xdgConfigHome.isEmpty())
        xdgConfigHome = QDir::homePath() + QLatin1String("/.config");
    QFile file(xdgConfigHome + QLatin1String("/user-dirs.dirs"));
    const QLatin1String key = xdg_key_name(type);
    if (!key.isEmpty() && !isTestModeEnabled() && file.open(QIODevice::ReadOnly)) {
        QTextStream stream(&file);
        // Only look for lines like: XDG_DESKTOP_DIR="$HOME/Desktop"
        QRegularExpression exp(QLatin1String("^XDG_(.*)_DIR=(.*)$"));
        QString result;
        while (!stream.atEnd()) {
            const QString &line = stream.readLine();
            QRegularExpressionMatch match = exp.match(line);
            if (match.hasMatch() && match.capturedView(1) == key) {
                QStringView value = match.capturedView(2);
                if (value.length() > 2
                    && value.startsWith(QLatin1Char('\"'))
                    && value.endsWith(QLatin1Char('\"')))
                    value = value.mid(1, value.length() - 2);
                // value can start with $HOME
                if (value.startsWith(QLatin1String("$HOME")))
                    result = QDir::homePath() + value.mid(5);
                else
                    result = value.toString();
                if (result.length() > 1 && result.endsWith(QLatin1Char('/')))
                    result.chop(1);
            }
        }
        if (!result.isNull())
            return result;
    }
#endif // QT_CONFIG(regularexpression)

    QString path;
    switch (type) {
    case DesktopLocation:
        path = QDir::homePath() + QLatin1String("/Desktop");
        break;
    case DocumentsLocation:
        path = QDir::homePath() + QLatin1String("/Documents");
       break;
    case PicturesLocation:
        path = QDir::homePath() + QLatin1String("/Pictures");
        break;

    case FontsLocation:
        path = writableLocation(GenericDataLocation) + QLatin1String("/fonts");
        break;

    case MusicLocation:
        path = QDir::homePath() + QLatin1String("/Music");
        break;

    case MoviesLocation:
        path = QDir::homePath() + QLatin1String("/Videos");
        break;
    case DownloadLocation:
        path = QDir::homePath() + QLatin1String("/Downloads");
        break;
    case ApplicationsLocation:
        path = writableLocation(GenericDataLocation) + QLatin1String("/applications");
        break;

    default:
        break;
    }

    return path;
}

static QStringList xdgDataDirs()
{
    QStringList dirs;
    // http://standards.freedesktop.org/basedir-spec/latest/
    QString xdgDataDirsEnv = QFile::decodeName(qgetenv("XDG_DATA_DIRS"));
    if (xdgDataDirsEnv.isEmpty()) {
        dirs.append(QString::fromLatin1("/usr/local/share"));
        dirs.append(QString::fromLatin1("/usr/share"));
    } else {
        const auto parts = xdgDataDirsEnv.splitRef(QLatin1Char(':'), Qt::SkipEmptyParts);

        // Normalize paths, skip relative paths
        for (const QStringRef &dir : parts) {
            if (dir.startsWith(QLatin1Char('/')))
                dirs.push_back(QDir::cleanPath(dir.toString()));
        }

        // Remove duplicates from the list, there's no use for duplicated
        // paths in XDG_DATA_DIRS - if it's not found in the given
        // directory the first time, it won't be there the second time.
        // Plus duplicate paths causes problems for example for mimetypes,
        // where duplicate paths here lead to duplicated mime types returned
        // for a file, eg "text/plain,text/plain" instead of "text/plain"
        dirs.removeDuplicates();
    }
    return dirs;
}

static QStringList xdgConfigDirs()
{
    QStringList dirs;
    // http://standards.freedesktop.org/basedir-spec/latest/
    const QString xdgConfigDirs = QFile::decodeName(qgetenv("XDG_CONFIG_DIRS"));
    if (xdgConfigDirs.isEmpty())
        dirs.append(QString::fromLatin1("/etc/xdg"));
    else
        dirs = xdgConfigDirs.split(QLatin1Char(':'));
    return dirs;
}

QStringList QStandardPaths::standardLocations(StandardLocation type)
{
    QStringList dirs;
    switch (type) {
    case ConfigLocation:
    case GenericConfigLocation:
        dirs = xdgConfigDirs();
        break;
    case AppConfigLocation:
        dirs = xdgConfigDirs();
        for (int i = 0; i < dirs.count(); ++i)
            appendOrganizationAndApp(dirs[i]);
        break;
    case GenericDataLocation:
        dirs = xdgDataDirs();
        break;
    case ApplicationsLocation:
        dirs = xdgDataDirs();
        for (int i = 0; i < dirs.count(); ++i)
            dirs[i].append(QLatin1String("/applications"));
        break;
    case AppDataLocation:
    case AppLocalDataLocation:
        dirs = xdgDataDirs();
        for (int i = 0; i < dirs.count(); ++i)
            appendOrganizationAndApp(dirs[i]);
        break;
    case FontsLocation:
        dirs += QDir::homePath() + QLatin1String("/.fonts");
        dirs += xdgDataDirs();
        for (int i = 1; i < dirs.count(); ++i)
            dirs[i].append(QLatin1String("/fonts"));
        break;
    default:
        break;
    }
    const QString localDir = writableLocation(type);
    dirs.prepend(localDir);
    return dirs;
}

QT_END_NAMESPACE

#endif // QT_NO_STANDARDPATHS