qsettings.cpp

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// Copyright (C) 2022 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 <qdebug.h>
#include "qplatformdefs.h"
#include "qsettings.h"
 
#include "qsettings_p.h"
#include "qcache.h"
#include "qfile.h"
#include "qdir.h"
#include "qfileinfo.h"
#include "qmutex.h"
#include "private/qlocking_p.h"
#include "private/qtools_p.h"
#include "qlibraryinfo.h"
#include "qtemporaryfile.h"
#include "qstandardpaths.h"
#include <qdatastream.h>
#include "private/qstringconverter_p.h"
 
#ifndef QT_NO_GEOM_VARIANT
#include "qsize.h"
#include "qpoint.h"
#include "qrect.h"
#endif // !QT_NO_GEOM_VARIANT
 
#include "qcoreapplication.h"
 
#ifndef QT_BOOTSTRAPPED
#include "qsavefile.h"
#include "qlockfile.h"
#endif
 
#ifdef Q_OS_VXWORKS
#  include <ioLib.h>
#endif
 
#include <algorithm>
#include <stdlib.h>
 
#ifdef Q_OS_WIN // for homedirpath reading from registry
#  include <qt_windows.h>
#  include <shlobj.h>
#endif
 
#if defined(Q_OS_UNIX) && !defined(Q_OS_DARWIN) && !defined(Q_OS_ANDROID)
#define Q_XDG_PLATFORM
#endif
 
#if !defined(QT_NO_STANDARDPATHS)                                                                  \
        && (defined(Q_XDG_PLATFORM) || defined(QT_PLATFORM_UIKIT) || defined(Q_OS_ANDROID))
#    define QSETTINGS_USE_QSTANDARDPATHS
#endif
 
// ************************************************************************
// QConfFile
 
/*
    QConfFile objects are explicitly shared within the application.
    This ensures that modification to the settings done through one
    QSettings object are immediately reflected in other setting
    objects of the same application.
*/
 
QT_BEGIN_NAMESPACE
 
using namespace Qt::StringLiterals;
using namespace QtMiscUtils;
 
struct QConfFileCustomFormat
{
    QString extension;
    QSettings::ReadFunc readFunc;
    QSettings::WriteFunc writeFunc;
    Qt::CaseSensitivity caseSensitivity;
};
Q_DECLARE_TYPEINFO(QConfFileCustomFormat, Q_RELOCATABLE_TYPE);
 
typedef QHash<QString, QConfFile *> ConfFileHash;
typedef QCache<QString, QConfFile> ConfFileCache;
namespace {
    struct Path
    {
        // Note: Defining constructors explicitly because of buggy C++11
        // implementation in MSVC (uniform initialization).
        Path() {}
        Path(const QString & p, bool ud) : path(p), userDefined(ud) {}
        QString path;
        bool userDefined = false; 
    };
}
typedef QHash<int, Path> PathHash;
typedef QList<QConfFileCustomFormat> CustomFormatVector;
 
Q_GLOBAL_STATIC(ConfFileHash, usedHashFunc)
Q_GLOBAL_STATIC(ConfFileCache, unusedCacheFunc)
Q_GLOBAL_STATIC(PathHash, pathHashFunc)
Q_GLOBAL_STATIC(CustomFormatVector, customFormatVectorFunc)
 
Q_CONSTINIT static QBasicMutex settingsGlobalMutex;
 
Q_CONSTINIT static QSettings::Format globalDefaultFormat = QSettings::NativeFormat;
 
QConfFile::QConfFile(const QString &fileName, bool _userPerms)
    : name(fileName), size(0), ref(1), userPerms(_userPerms)
{
    usedHashFunc()->insert(name, this);
}
 
QConfFile::~QConfFile()
{
    if (usedHashFunc())
        usedHashFunc()->remove(name);
}
 
ParsedSettingsMap QConfFile::mergedKeyMap() const
{
    ParsedSettingsMap result = originalKeys;
 
    for (auto i = removedKeys.begin(); i != removedKeys.end(); ++i)
        result.remove(i.key());
    for (auto i = addedKeys.begin(); i != addedKeys.end(); ++i)
        result.insert(i.key(), i.value());
    return result;
}
 
bool QConfFile::isWritable() const
{
    QFileInfo fileInfo(name);
 
#ifndef QT_NO_TEMPORARYFILE
    if (fileInfo.exists()) {
#endif
        QFile file(name);
        return file.open(QFile::ReadWrite);
#ifndef QT_NO_TEMPORARYFILE
    } else {
        // Create the directories to the file.
        QDir dir(fileInfo.absolutePath());
        if (!dir.exists()) {
            if (!dir.mkpath(dir.absolutePath()))
                return false;
        }
 
        // we use a temporary file to avoid race conditions
        QTemporaryFile file(name);
        return file.open();
    }
#endif
}
 
QConfFile *QConfFile::fromName(const QString &fileName, bool _userPerms)
{
    QString absPath = QFileInfo(fileName).absoluteFilePath();
 
    ConfFileHash *usedHash = usedHashFunc();
    ConfFileCache *unusedCache = unusedCacheFunc();
 
    QConfFile *confFile = nullptr;
    const auto locker = qt_scoped_lock(settingsGlobalMutex);
 
    if (!(confFile = usedHash->value(absPath))) {
        if ((confFile = unusedCache->take(absPath)))
            usedHash->insert(absPath, confFile);
    }
    if (confFile) {
        confFile->ref.ref();
        return confFile;
    }
    return new QConfFile(absPath, _userPerms);
}
 
void QConfFile::clearCache()
{
    const auto locker = qt_scoped_lock(settingsGlobalMutex);
    unusedCacheFunc()->clear();
}
 
// ************************************************************************
// QSettingsPrivate
 
QSettingsPrivate::QSettingsPrivate(QSettings::Format format)
    : format(format), scope(QSettings::UserScope /* nothing better to put */), fallbacks(true),
      pendingChanges(false), status(QSettings::NoError)
{
}
 
QSettingsPrivate::QSettingsPrivate(QSettings::Format format, QSettings::Scope scope,
                                   const QString &organization, const QString &application)
    : format(format), scope(scope), organizationName(organization), applicationName(application),
      fallbacks(true), pendingChanges(false), status(QSettings::NoError)
{
}
 
QSettingsPrivate::~QSettingsPrivate()
{
}
 
QString QSettingsPrivate::actualKey(QAnyStringView key) const
{
    auto n = normalizedKey(key);
    Q_ASSERT_X(!n.isEmpty(), "QSettings", "empty key");
    return groupPrefix + n;
}
 
namespace {
    // ### this needs some public API (QStringConverter?)
    QChar *write(QChar *out, QUtf8StringView v)
    {
        return QUtf8::convertToUnicode(out, QByteArrayView(v));
    }
    QChar *write(QChar *out, QLatin1StringView v)
    {
        return QLatin1::convertToUnicode(out, v);
    }
    QChar *write(QChar *out, QStringView v)
    {
        memcpy(out, v.data(), v.size() * sizeof(QChar));
        return out + v.size();
    }
}
 
/*
    Returns a string that never starts nor ends with a slash (or an
    empty string). Examples:
 
            "foo"            becomes   "foo"
            "/foo//bar///"   becomes   "foo/bar"
            "///"            becomes   ""
*/
QString QSettingsPrivate::normalizedKey(QAnyStringView key)
{
    QString result(key.size(), Qt::Uninitialized);
    auto out = const_cast<QChar*>(result.constData()); // don't detach
 
    const bool maybeEndsInSlash = key.visit([&out](auto key) {
        using View = decltype(key);
 
        auto it = key.begin();
        const auto end = key.end();
 
        while (it != end) {
            while (*it == u'/') {
                ++it;
                if (it == end)
                    return true;
            }
            auto mark = it;
            while (*it != u'/') {
                ++it;
                if (it == end)
                    break;
            }
            out = write(out, View{mark, it});
            if (it == end)
                return false;
            Q_ASSERT(*it == u'/');
            *out++ = u'/';
            ++it;
        }
        return true;
    });
 
    if (maybeEndsInSlash && out != result.constData())
        --out; // remove the trailing slash
    result.truncate(out - result.constData());
    return result;
}
 
// see also qsettings_win.cpp and qsettings_mac.cpp
 
#if !defined(Q_OS_WIN) && !defined(Q_OS_DARWIN) && !defined(Q_OS_WASM)
QSettingsPrivate *QSettingsPrivate::create(QSettings::Format format, QSettings::Scope scope,
                                           const QString &organization, const QString &application)
{
    return new QConfFileSettingsPrivate(format, scope, organization, application);
}
#endif
 
#if !defined(Q_OS_WIN)
QSettingsPrivate *QSettingsPrivate::create(const QString &fileName, QSettings::Format format)
{
    return new QConfFileSettingsPrivate(fileName, format);
}
#endif
 
void QSettingsPrivate::processChild(QStringView key, ChildSpec spec, QStringList &result)
{
    if (spec != AllKeys) {
        qsizetype slashPos = key.indexOf(u'/');
        if (slashPos == -1) {
            if (spec != ChildKeys)
                return;
        } else {
            if (spec != ChildGroups)
                return;
            key.truncate(slashPos);
        }
    }
    result.append(key.toString());
}
 
void QSettingsPrivate::beginGroupOrArray(const QSettingsGroup &group)
{
    groupStack.push(group);
    const QString name = group.name();
    if (!name.isEmpty())
        groupPrefix += name + u'/';
}
 
/*
    We only set an error if there isn't one set already. This way the user always gets the
    first error that occurred. We always allow clearing errors.
*/
 
void QSettingsPrivate::setStatus(QSettings::Status status) const
{
    if (status == QSettings::NoError || this->status == QSettings::NoError)
        this->status = status;
}
 
void QSettingsPrivate::update()
{
    flush();
    pendingChanges = false;
}
 
void QSettingsPrivate::requestUpdate()
{
    if (!pendingChanges) {
        pendingChanges = true;
#ifndef QT_NO_QOBJECT
        Q_Q(QSettings);
        QCoreApplication::postEvent(q, new QEvent(QEvent::UpdateRequest));
#else
        update();
#endif
    }
}
 
QStringList QSettingsPrivate::variantListToStringList(const QVariantList &l)
{
    QStringList result;
    result.reserve(l.size());
    for (auto v : l)
        result.append(variantToString(v));
    return result;
}
 
QVariant QSettingsPrivate::stringListToVariantList(const QStringList &l)
{
    QStringList outStringList = l;
    for (qsizetype i = 0; i < outStringList.size(); ++i) {
        const QString &str = outStringList.at(i);
 
        if (str.startsWith(u'@')) {
            if (str.size() < 2 || str.at(1) != u'@') {
                QVariantList variantList;
                variantList.reserve(l.size());
                for (const auto &s : l)
                    variantList.append(stringToVariant(s));
                return variantList;
            }
            outStringList[i].remove(0, 1);
        }
    }
    return outStringList;
}
 
QString QSettingsPrivate::variantToString(const QVariant &v)
{
    QString result;
 
    switch (v.metaType().id()) {
        case QMetaType::UnknownType:
            result = "@Invalid()"_L1;
            break;
 
        case QMetaType::QByteArray: {
            QByteArray a = v.toByteArray();
            result = "@ByteArray("_L1 + QLatin1StringView(a) + u')';
            break;
        }
 
#if QT_CONFIG(shortcut)
        case QMetaType::QKeySequence:
#endif
        case QMetaType::QString:
        case QMetaType::LongLong:
        case QMetaType::ULongLong:
        case QMetaType::Int:
        case QMetaType::UInt:
        case QMetaType::Bool:
        case QMetaType::Float:
        case QMetaType::Double: {
            result = v.toString();
            if (result.contains(QChar::Null))
                result = "@String("_L1 + result + u')';
            else if (result.startsWith(u'@'))
                result.prepend(u'@');
            break;
        }
#ifndef QT_NO_GEOM_VARIANT
        case QMetaType::QRect: {
            QRect r = qvariant_cast<QRect>(v);
            result = QString::asprintf("@Rect(%d %d %d %d)", r.x(), r.y(), r.width(), r.height());
            break;
        }
        case QMetaType::QSize: {
            QSize s = qvariant_cast<QSize>(v);
            result = QString::asprintf("@Size(%d %d)", s.width(), s.height());
            break;
        }
        case QMetaType::QPoint: {
            QPoint p = qvariant_cast<QPoint>(v);
            result = QString::asprintf("@Point(%d %d)", p.x(), p.y());
            break;
        }
#endif // !QT_NO_GEOM_VARIANT
 
        default: {
#ifndef QT_NO_DATASTREAM
            QDataStream::Version version;
            const char *typeSpec;
            if (v.userType() == QMetaType::QDateTime) {
                version = QDataStream::Qt_5_6;
                typeSpec = "@DateTime(";
            } else {
                version = QDataStream::Qt_4_0;
                typeSpec = "@Variant(";
            }
            QByteArray a;
            {
                QDataStream s(&a, QIODevice::WriteOnly);
                s.setVersion(version);
                s << v;
            }
 
            result = QLatin1StringView(typeSpec)
                     + QLatin1StringView(a.constData(), a.size())
                     + u')';
#else
            Q_ASSERT(!"QSettings: Cannot save custom types without QDataStream support");
#endif
            break;
        }
    }
 
    return result;
}
 
 
QVariant QSettingsPrivate::stringToVariant(const QString &s)
{
    if (s.startsWith(u'@')) {
        if (s.endsWith(u')')) {
            if (s.startsWith("@ByteArray("_L1)) {
                return QVariant(QStringView{s}.sliced(11).chopped(1).toLatin1());
            } else if (s.startsWith("@String("_L1)) {
                return QVariant(QStringView{s}.sliced(8).chopped(1).toString());
            } else if (s.startsWith("@Variant("_L1)
                       || s.startsWith("@DateTime("_L1)) {
#ifndef QT_NO_DATASTREAM
                QDataStream::Version version;
                int offset;
                if (s.at(1) == u'D') {
                    version = QDataStream::Qt_5_6;
                    offset = 10;
                } else {
                    version = QDataStream::Qt_4_0;
                    offset = 9;
                }
                QByteArray a = QStringView{s}.sliced(offset).toLatin1();
                QDataStream stream(&a, QIODevice::ReadOnly);
                stream.setVersion(version);
                QVariant result;
                stream >> result;
                return result;
#else
                Q_ASSERT(!"QSettings: Cannot load custom types without QDataStream support");
#endif
#ifndef QT_NO_GEOM_VARIANT
            } else if (s.startsWith("@Rect("_L1)) {
                QStringList args = QSettingsPrivate::splitArgs(s, 5);
                if (args.size() == 4)
                    return QVariant(QRect(args[0].toInt(), args[1].toInt(), args[2].toInt(), args[3].toInt()));
            } else if (s.startsWith("@Size("_L1)) {
                QStringList args = QSettingsPrivate::splitArgs(s, 5);
                if (args.size() == 2)
                    return QVariant(QSize(args[0].toInt(), args[1].toInt()));
            } else if (s.startsWith("@Point("_L1)) {
                QStringList args = QSettingsPrivate::splitArgs(s, 6);
                if (args.size() == 2)
                    return QVariant(QPoint(args[0].toInt(), args[1].toInt()));
#endif
            } else if (s == "@Invalid()"_L1) {
                return QVariant();
            }
 
        }
        if (s.startsWith("@@"_L1))
            return QVariant(s.sliced(1));
    }
 
    return QVariant(s);
}
 
void QSettingsPrivate::iniEscapedKey(const QString &key, QByteArray &result)
{
    result.reserve(result.size() + key.size() * 3 / 2);
    for (qsizetype i = 0; i < key.size(); ++i) {
        uint ch = key.at(i).unicode();
 
        if (ch == '/') {
            result += '\\';
        } else if (isAsciiLetterOrNumber(ch) || ch == '_' || ch == '-' || ch == '.') {
            result += (char)ch;
        } else if (ch <= 0xFF) {
            result += '%';
            result += QtMiscUtils::toHexUpper(ch / 16);
            result += QtMiscUtils::toHexUpper(ch % 16);
        } else {
            result += "%U";
            QByteArray hexCode;
            for (int j = 0; j < 4; ++j) {
                hexCode.prepend(QtMiscUtils::toHexUpper(ch % 16));
                ch >>= 4;
            }
            result += hexCode;
        }
    }
}
 
bool QSettingsPrivate::iniUnescapedKey(QByteArrayView key, QString &result)
{
    const QString decoded = QString::fromUtf8(key);
    const qsizetype size = decoded.size();
    result.reserve(result.size() + size);
    qsizetype i = 0;
    bool lowercaseOnly = true;
    while (i < size) {
        char16_t ch = decoded.at(i).unicode();
 
        if (ch == '\\') {
            result += u'/';
            ++i;
            continue;
        }
 
        if (ch != '%' || i == size - 1) {
            QChar qch(ch);
            if (qch.isUpper())
                lowercaseOnly = false;
            result += qch;
            ++i;
            continue;
        }
 
        int numDigits = 2;
        qsizetype firstDigitPos = i + 1;
 
        ch = decoded.at(i + 1).unicode();
        if (ch == 'U') {
            ++firstDigitPos;
            numDigits = 4;
        }
 
        if (firstDigitPos + numDigits > size) {
            result += u'%';
            ++i;
            continue;
        }
 
        bool ok;
        ch = QStringView(decoded).sliced(firstDigitPos, numDigits).toUShort(&ok, 16);
        if (!ok) {
            result += u'%';
            ++i;
            continue;
        }
 
        QChar qch(ch);
        if (qch.isUpper())
            lowercaseOnly = false;
        result += qch;
        i = firstDigitPos + numDigits;
    }
    return lowercaseOnly;
}
 
void QSettingsPrivate::iniEscapedString(const QString &str, QByteArray &result)
{
    bool needsQuotes = false;
    bool escapeNextIfDigit = false;
    const bool useCodec = !(str.startsWith("@ByteArray("_L1)
                            || str.startsWith("@Variant("_L1)
                            || str.startsWith("@DateTime("_L1));
    const qsizetype startPos = result.size();
 
    QStringEncoder toUtf8(QStringEncoder::Utf8);
 
    result.reserve(startPos + str.size() * 3 / 2);
    for (QChar qch : str) {
        uint ch = qch.unicode();
        if (ch == ';' || ch == ',' || ch == '=')
            needsQuotes = true;
 
        if (escapeNextIfDigit && isHexDigit(ch)) {
            result += "\\x" + QByteArray::number(ch, 16);
            continue;
        }
 
        escapeNextIfDigit = false;
 
        switch (ch) {
        case '\0':
            result += "\\0";
            escapeNextIfDigit = true;
            break;
        case '\a':
            result += "\\a";
            break;
        case '\b':
            result += "\\b";
            break;
        case '\f':
            result += "\\f";
            break;
        case '\n':
            result += "\\n";
            break;
        case '\r':
            result += "\\r";
            break;
        case '\t':
            result += "\\t";
            break;
        case '\v':
            result += "\\v";
            break;
        case '"':
        case '\\':
            result += '\\';
            result += (char)ch;
            break;
        default:
            if (ch <= 0x1F || (ch >= 0x7F && !useCodec)) {
                result += "\\x" + QByteArray::number(ch, 16);
                escapeNextIfDigit = true;
            } else if (useCodec) {
                // slow
                result += toUtf8(qch);
            } else {
                result += (char)ch;
            }
        }
    }
 
    if (needsQuotes
            || (startPos < result.size() && (result.at(startPos) == ' '
                                                || result.at(result.size() - 1) == ' '))) {
        result.insert(startPos, '"');
        result += '"';
    }
}
 
inline static void iniChopTrailingSpaces(QString &str, qsizetype limit)
{
    qsizetype n = str.size() - 1;
    QChar ch;
    while (n >= limit && ((ch = str.at(n)) == u' ' || ch == u'\t'))
        str.truncate(n--);
}
 
void QSettingsPrivate::iniEscapedStringList(const QStringList &strs, QByteArray &result)
{
    if (strs.isEmpty()) {
        /*
            We need to distinguish between empty lists and one-item
            lists that contain an empty string. Ideally, we'd have a
            @EmptyList() symbol but that would break compatibility
            with Qt 4.0. @Invalid() stands for QVariant(), and
            QVariant().toStringList() returns an empty QStringList,
            so we're in good shape.
        */
        result += "@Invalid()";
    } else {
        for (qsizetype i = 0; i < strs.size(); ++i) {
            if (i != 0)
                result += ", ";
            iniEscapedString(strs.at(i), result);
        }
    }
}
 
bool QSettingsPrivate::iniUnescapedStringList(QByteArrayView str,
                                              QString &stringResult, QStringList &stringListResult)
{
    static const char escapeCodes[][2] =
    {
        { 'a', '\a' },
        { 'b', '\b' },
        { 'f', '\f' },
        { 'n', '\n' },
        { 'r', '\r' },
        { 't', '\t' },
        { 'v', '\v' },
        { '"', '"' },
        { '?', '?' },
        { '\'', '\'' },
        { '\\', '\\' }
    };
 
    bool isStringList = false;
    bool inQuotedString = false;
    bool currentValueIsQuoted = false;
    char16_t escapeVal = 0;
    qsizetype i = 0;
    char ch;
    QStringDecoder fromUtf8(QStringDecoder::Utf8);
 
StSkipSpaces:
    while (i < str.size() && ((ch = str.at(i)) == ' ' || ch == '\t'))
        ++i;
    // fallthrough
 
StNormal:
    qsizetype chopLimit = stringResult.size();
    while (i < str.size()) {
        switch (str.at(i)) {
        case '\\':
            ++i;
            if (i >= str.size())
                goto end;
 
            ch = str.at(i++);
            for (const auto &escapeCode : escapeCodes) {
                if (ch == escapeCode[0]) {
                    stringResult += QLatin1Char(escapeCode[1]);
                    goto StNormal;
                }
            }
 
            if (ch == 'x') {
                escapeVal = 0;
 
                if (i >= str.size())
                    goto end;
 
                ch = str.at(i);
                if (isHexDigit(ch))
                    goto StHexEscape;
            } else if (const int o = fromOct(ch); o != -1) {
                escapeVal = o;
                goto StOctEscape;
            } else if (ch == '\n' || ch == '\r') {
                if (i < str.size()) {
                    char ch2 = str.at(i);
                    // \n, \r, \r\n, and \n\r are legitimate line terminators in INI files
                    if ((ch2 == '\n' || ch2 == '\r') && ch2 != ch)
                        ++i;
                }
            } else {
                // the character is skipped
            }
            chopLimit = stringResult.size();
            break;
        case '"':
            ++i;
            currentValueIsQuoted = true;
            inQuotedString = !inQuotedString;
            if (!inQuotedString)
                goto StSkipSpaces;
            break;
        case ',':
            if (!inQuotedString) {
                if (!currentValueIsQuoted)
                    iniChopTrailingSpaces(stringResult, chopLimit);
                if (!isStringList) {
                    isStringList = true;
                    stringListResult.clear();
                    stringResult.squeeze();
                }
                stringListResult.append(stringResult);
                stringResult.clear();
                currentValueIsQuoted = false;
                ++i;
                goto StSkipSpaces;
            }
            Q_FALLTHROUGH();
        default: {
            qsizetype j = i + 1;
            while (j < str.size()) {
                ch = str.at(j);
                if (ch == '\\' || ch == '"' || ch == ',')
                    break;
                ++j;
            }
 
            stringResult += fromUtf8(str.first(j).sliced(i));
            i = j;
        }
        }
    }
    if (!currentValueIsQuoted)
        iniChopTrailingSpaces(stringResult, chopLimit);
    goto end;
 
StHexEscape:
    if (i >= str.size()) {
        stringResult += escapeVal;
        goto end;
    }
 
    ch = str.at(i);
    if (const int h = fromHex(ch); h != -1) {
        escapeVal <<= 4;
        escapeVal += h;
        ++i;
        goto StHexEscape;
    } else {
        stringResult += escapeVal;
        goto StNormal;
    }
 
StOctEscape:
    if (i >= str.size()) {
        stringResult += escapeVal;
        goto end;
    }
 
    ch = str.at(i);
    if (const int o = fromOct(ch); o != -1) {
        escapeVal <<= 3;
        escapeVal += o;
        ++i;
        goto StOctEscape;
    } else {
        stringResult += escapeVal;
        goto StNormal;
    }
 
end:
    if (isStringList)
        stringListResult.append(stringResult);
    return isStringList;
}
 
QStringList QSettingsPrivate::splitArgs(const QString &s, qsizetype idx)
{
    qsizetype l = s.size();
    Q_ASSERT(l > 0);
    Q_ASSERT(s.at(idx) == u'(');
    Q_ASSERT(s.at(l - 1) == u')');
 
    QStringList result;
    QString item;
 
    for (++idx; idx < l; ++idx) {
        QChar c = s.at(idx);
        if (c == u')') {
            Q_ASSERT(idx == l - 1);
            result.append(item);
        } else if (c == u' ') {
            result.append(item);
            item.clear();
        } else {
            item.append(c);
        }
    }
 
    return result;
}
 
// ************************************************************************
// QConfFileSettingsPrivate
 
void QConfFileSettingsPrivate::initFormat()
{
    extension = (format == QSettings::NativeFormat) ? ".conf"_L1 : ".ini"_L1;
    readFunc = nullptr;
    writeFunc = nullptr;
#if defined(Q_OS_DARWIN)
    caseSensitivity = (format == QSettings::NativeFormat) ? Qt::CaseSensitive : IniCaseSensitivity;
#else
    caseSensitivity = IniCaseSensitivity;
#endif
 
    if (format > QSettings::IniFormat) {
        const auto locker = qt_scoped_lock(settingsGlobalMutex);
        const CustomFormatVector *customFormatVector = customFormatVectorFunc();
 
        qsizetype i = qsizetype(format) - qsizetype(QSettings::CustomFormat1);
        if (i >= 0 && i < customFormatVector->size()) {
            QConfFileCustomFormat info = customFormatVector->at(i);
            extension = info.extension;
            readFunc = info.readFunc;
            writeFunc = info.writeFunc;
            caseSensitivity = info.caseSensitivity;
        }
    }
}
 
void QConfFileSettingsPrivate::initAccess()
{
    if (!confFiles.isEmpty()) {
        if (format > QSettings::IniFormat) {
            if (!readFunc)
                setStatus(QSettings::AccessError);
        }
    }
 
    sync();       // loads the files the first time
}
 
#if defined(Q_OS_WIN)
static QString windowsConfigPath(const KNOWNFOLDERID &type)
{
    QString result;
 
    PWSTR path = nullptr;
    if (SHGetKnownFolderPath(type, KF_FLAG_DONT_VERIFY, NULL, &path) == S_OK) {
        result = QString::fromWCharArray(path);
        CoTaskMemFree(path);
    }
 
    if (result.isEmpty()) {
        if (type == FOLDERID_ProgramData) {
            result = "C:\\temp\\qt-common"_L1;
        } else if (type == FOLDERID_RoamingAppData) {
            result = "C:\\temp\\qt-user"_L1;
        }
    }
 
    return result;
}
#endif // Q_OS_WIN
 
static inline int pathHashKey(QSettings::Format format, QSettings::Scope scope)
{
    return int((uint(format) << 1) | uint(scope == QSettings::SystemScope));
}
 
#ifndef Q_OS_WIN
static constexpr QChar sep = u'/';
 
#if !defined(QSETTINGS_USE_QSTANDARDPATHS) || defined(Q_OS_ANDROID)
static QString make_user_path_without_qstandard_paths()
{
    QByteArray env = qgetenv("XDG_CONFIG_HOME");
    if (env.isEmpty()) {
        return QDir::homePath() + "/.config/"_L1;
    } else if (env.startsWith('/')) {
        return QFile::decodeName(env) + sep;
    }
 
    return QDir::homePath() + sep + QFile::decodeName(env) + sep;
}
#endif // !QSETTINGS_USE_QSTANDARDPATHS || Q_OS_ANDROID
 
static QString make_user_path()
{
#ifndef QSETTINGS_USE_QSTANDARDPATHS
    // Non XDG platforms (OS X, iOS, Android...) have used this code path erroneously
    // for some time now. Moving away from that would require migrating existing settings.
    // The migration has already been done for Android.
    return make_user_path_without_qstandard_paths();
#else
 
#ifdef Q_OS_ANDROID
    // If an old settings path exists, use it instead of creating a new one
    QString ret = make_user_path_without_qstandard_paths();
    if (QFile(ret).exists())
        return ret;
#endif // Q_OS_ANDROID
 
    // When using a proper XDG platform or Android platform, use QStandardPaths rather than the
    // above hand-written code. It makes the use of test mode from unit tests possible.
    // Ideally all platforms should use this, but see above for the migration issue.
    return QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + sep;
#endif // !QSETTINGS_USE_QSTANDARDPATHS
}
#endif // !Q_OS_WIN
 
static std::unique_lock<QBasicMutex> initDefaultPaths(std::unique_lock<QBasicMutex> locker)
{
    PathHash *pathHash = pathHashFunc();
 
    locker.unlock();
 
    /*
       QLibraryInfo::path() uses QSettings, so in order to
       avoid a dead-lock, we can't hold the global mutex while
       calling it.
    */
    QString systemPath = QLibraryInfo::path(QLibraryInfo::SettingsPath) + u'/';
 
    locker.lock();
    if (pathHash->isEmpty()) {
        /*
           Lazy initialization of pathHash. We initialize the
           IniFormat paths and (on Unix) the NativeFormat paths.
           (The NativeFormat paths are not configurable for the
           Windows registry and the Mac CFPreferences.)
       */
#ifdef Q_OS_WIN
        const QString roamingAppDataFolder = windowsConfigPath(FOLDERID_RoamingAppData);
        const QString programDataFolder = windowsConfigPath(FOLDERID_ProgramData);
        pathHash->insert(pathHashKey(QSettings::IniFormat, QSettings::UserScope),
                         Path(roamingAppDataFolder + QDir::separator(), false));
        pathHash->insert(pathHashKey(QSettings::IniFormat, QSettings::SystemScope),
                         Path(programDataFolder + QDir::separator(), false));
#else
        const QString userPath = make_user_path();
        pathHash->insert(pathHashKey(QSettings::IniFormat, QSettings::UserScope), Path(userPath, false));
        pathHash->insert(pathHashKey(QSettings::IniFormat, QSettings::SystemScope), Path(systemPath, false));
#ifndef Q_OS_DARWIN
        pathHash->insert(pathHashKey(QSettings::NativeFormat, QSettings::UserScope), Path(userPath, false));
        pathHash->insert(pathHashKey(QSettings::NativeFormat, QSettings::SystemScope), Path(systemPath, false));
#endif
#endif // Q_OS_WIN
    }
 
    return locker;
}
 
static Path getPath(QSettings::Format format, QSettings::Scope scope)
{
    Q_ASSERT(int(QSettings::NativeFormat) == 0);
    Q_ASSERT(int(QSettings::IniFormat) == 1);
 
    auto locker = qt_unique_lock(settingsGlobalMutex);
    PathHash *pathHash = pathHashFunc();
    if (pathHash->isEmpty())
        locker = initDefaultPaths(std::move(locker));
 
    Path result = pathHash->value(pathHashKey(format, scope));
    if (!result.path.isEmpty())
        return result;
 
    // fall back on INI path
    return pathHash->value(pathHashKey(QSettings::IniFormat, scope));
}
 
#if defined(QT_BUILD_INTERNAL) && defined(Q_XDG_PLATFORM) && !defined(QT_NO_STANDARDPATHS)
// Note: Suitable only for autotests.
void Q_AUTOTEST_EXPORT clearDefaultPaths()
{
    const auto locker = qt_scoped_lock(settingsGlobalMutex);
    pathHashFunc()->clear();
}
#endif // QT_BUILD_INTERNAL && Q_XDG_PLATFORM && !QT_NO_STANDARDPATHS
 
QConfFileSettingsPrivate::QConfFileSettingsPrivate(QSettings::Format format,
                                                   QSettings::Scope scope,
                                                   const QString &organization,
                                                   const QString &application)
    : QSettingsPrivate(format, scope, organization, application),
      nextPosition(0x40000000) // big positive number
{
    initFormat();
 
    QString org = organization;
    if (org.isEmpty()) {
        setStatus(QSettings::AccessError);
        org = "Unknown Organization"_L1;
    }
 
    QString appFile = org + QDir::separator() + application + extension;
    QString orgFile = org + extension;
 
    if (scope == QSettings::UserScope) {
        Path userPath = getPath(format, QSettings::UserScope);
        if (!application.isEmpty())
            confFiles.append(QConfFile::fromName(userPath.path + appFile, true));
        confFiles.append(QConfFile::fromName(userPath.path + orgFile, true));
    }
 
    Path systemPath = getPath(format, QSettings::SystemScope);
#if defined(Q_XDG_PLATFORM) && !defined(QT_NO_STANDARDPATHS)
    // check if the systemPath wasn't overridden by QSettings::setPath()
    if (!systemPath.userDefined) {
        // Note: We can't use QStandardPaths::locateAll() as we need all the
        // possible files (not just the existing ones) and there is no way
        // to exclude user specific (XDG_CONFIG_HOME) directory from the search.
        QStringList dirs = QStandardPaths::standardLocations(QStandardPaths::GenericConfigLocation);
        // remove the QStandardLocation::writableLocation() (XDG_CONFIG_HOME)
        if (!dirs.isEmpty())
            dirs.takeFirst();
        QStringList paths;
        if (!application.isEmpty()) {
            paths.reserve(dirs.size() * 2);
            for (const auto &dir : std::as_const(dirs))
                paths.append(dir + u'/' + appFile);
        } else {
            paths.reserve(dirs.size());
        }
        for (const auto &dir : std::as_const(dirs))
            paths.append(dir + u'/' + orgFile);
 
        // Note: No check for existence of files is done intentionally.
        for (const auto &path : std::as_const(paths))
            confFiles.append(QConfFile::fromName(path, false));
    } else
#endif // Q_XDG_PLATFORM && !QT_NO_STANDARDPATHS
    {
        if (!application.isEmpty())
            confFiles.append(QConfFile::fromName(systemPath.path + appFile, false));
        confFiles.append(QConfFile::fromName(systemPath.path + orgFile, false));
    }
 
#ifndef Q_OS_WASM // wasm needs to delay access until after file sync
    initAccess();
#endif
}
 
QConfFileSettingsPrivate::QConfFileSettingsPrivate(const QString &fileName,
                                                   QSettings::Format format)
    : QSettingsPrivate(format),
      nextPosition(0x40000000) // big positive number
{
    initFormat();
 
    confFiles.append(QConfFile::fromName(fileName, true));
 
    initAccess();
}
 
QConfFileSettingsPrivate::~QConfFileSettingsPrivate()
{
    const auto locker = qt_scoped_lock(settingsGlobalMutex);
    ConfFileHash *usedHash = usedHashFunc();
    ConfFileCache *unusedCache = unusedCacheFunc();
 
    for (auto conf_file : std::as_const(confFiles)) {
        if (!conf_file->ref.deref()) {
            if (conf_file->size == 0) {
                delete conf_file;
            } else {
                if (usedHash)
                    usedHash->remove(conf_file->name);
                if (unusedCache) {
                    QT_TRY {
                        // compute a better size?
                        unusedCache->insert(conf_file->name, conf_file,
                                            10 + (conf_file->originalKeys.size() / 4));
                    } QT_CATCH(...) {
                        // out of memory. Do not cache the file.
                        delete conf_file;
                    }
                } else {
                    // unusedCache is gone - delete the entry to prevent a memory leak
                    delete conf_file;
                }
            }
        }
    }
}
 
void QConfFileSettingsPrivate::remove(const QString &key)
{
    if (confFiles.isEmpty())
        return;
 
    // Note: First config file is always the most specific.
    QConfFile *confFile = confFiles.at(0);
 
    QSettingsKey theKey(key, caseSensitivity);
    QSettingsKey prefix(key + u'/', caseSensitivity);
    const auto locker = qt_scoped_lock(confFile->mutex);
 
    ensureSectionParsed(confFile, theKey);
    ensureSectionParsed(confFile, prefix);
 
    auto i = confFile->addedKeys.lowerBound(prefix);
    while (i != confFile->addedKeys.end() && i.key().startsWith(prefix))
        i = confFile->addedKeys.erase(i);
    confFile->addedKeys.remove(theKey);
 
    auto j = const_cast<const ParsedSettingsMap *>(&confFile->originalKeys)->lowerBound(prefix);
    while (j != confFile->originalKeys.constEnd() && j.key().startsWith(prefix)) {
        confFile->removedKeys.insert(j.key(), QVariant());
        ++j;
    }
    if (confFile->originalKeys.contains(theKey))
        confFile->removedKeys.insert(theKey, QVariant());
}
 
void QConfFileSettingsPrivate::set(const QString &key, const QVariant &value)
{
    if (confFiles.isEmpty())
        return;
 
    // Note: First config file is always the most specific.
    QConfFile *confFile = confFiles.at(0);
 
    QSettingsKey theKey(key, caseSensitivity, nextPosition++);
    const auto locker = qt_scoped_lock(confFile->mutex);
    confFile->removedKeys.remove(theKey);
    confFile->addedKeys.insert(theKey, value);
}
 
std::optional<QVariant> QConfFileSettingsPrivate::get(const QString &key) const
{
    QSettingsKey theKey(key, caseSensitivity);
    ParsedSettingsMap::const_iterator j;
    bool found = false;
 
    for (auto confFile : std::as_const(confFiles)) {
        const auto locker = qt_scoped_lock(confFile->mutex);
 
        if (!confFile->addedKeys.isEmpty()) {
            j = confFile->addedKeys.constFind(theKey);
            found = (j != confFile->addedKeys.constEnd());
        }
        if (!found) {
            ensureSectionParsed(confFile, theKey);
            j = confFile->originalKeys.constFind(theKey);
            found = (j != confFile->originalKeys.constEnd()
                     && !confFile->removedKeys.contains(theKey));
        }
 
        if (found)
            return *j;
        if (!fallbacks)
            break;
    }
    return std::nullopt;
}
 
QStringList QConfFileSettingsPrivate::children(const QString &prefix, ChildSpec spec) const
{
    QStringList result;
 
    QSettingsKey thePrefix(prefix, caseSensitivity);
    qsizetype startPos = prefix.size();
 
    for (auto confFile : std::as_const(confFiles)) {
        const auto locker = qt_scoped_lock(confFile->mutex);
 
        if (thePrefix.isEmpty())
            ensureAllSectionsParsed(confFile);
        else
            ensureSectionParsed(confFile, thePrefix);
 
        auto j = const_cast<const ParsedSettingsMap *>(
                &confFile->originalKeys)->lowerBound( thePrefix);
        while (j != confFile->originalKeys.constEnd() && j.key().startsWith(thePrefix)) {
            if (!confFile->removedKeys.contains(j.key()))
                processChild(QStringView{j.key().originalCaseKey()}.sliced(startPos), spec, result);
            ++j;
        }
 
        j = const_cast<const ParsedSettingsMap *>(
                &confFile->addedKeys)->lowerBound(thePrefix);
        while (j != confFile->addedKeys.constEnd() && j.key().startsWith(thePrefix)) {
            processChild(QStringView{j.key().originalCaseKey()}.sliced(startPos), spec, result);
            ++j;
        }
 
        if (!fallbacks)
            break;
    }
    std::sort(result.begin(), result.end());
    result.erase(std::unique(result.begin(), result.end()),
                 result.end());
    return result;
}
 
void QConfFileSettingsPrivate::clear()
{
    if (confFiles.isEmpty())
        return;
 
    // Note: First config file is always the most specific.
    QConfFile *confFile = confFiles.at(0);
 
    const auto locker = qt_scoped_lock(confFile->mutex);
    ensureAllSectionsParsed(confFile);
    confFile->addedKeys.clear();
    confFile->removedKeys = confFile->originalKeys;
}
 
void QConfFileSettingsPrivate::sync()
{
    // people probably won't be checking the status a whole lot, so in case of
    // error we just try to go on and make the best of it
 
    for (auto confFile : std::as_const(confFiles)) {
        const auto locker = qt_scoped_lock(confFile->mutex);
        syncConfFile(confFile);
    }
}
 
void QConfFileSettingsPrivate::flush()
{
    sync();
}
 
QString QConfFileSettingsPrivate::fileName() const
{
    if (confFiles.isEmpty())
        return QString();
 
    // Note: First config file is always the most specific.
    return confFiles.at(0)->name;
}
 
bool QConfFileSettingsPrivate::isWritable() const
{
    if (format > QSettings::IniFormat && !writeFunc)
        return false;
 
    if (confFiles.isEmpty())
        return false;
 
    return confFiles.at(0)->isWritable();
}
 
void QConfFileSettingsPrivate::syncConfFile(QConfFile *confFile)
{
    bool readOnly = confFile->addedKeys.isEmpty() && confFile->removedKeys.isEmpty();
 
    QFileInfo fileInfo(confFile->name);
    /*
        We can often optimize the read-only case, if the file on disk
        hasn't changed.
    */
    if (readOnly && confFile->size > 0) {
        if (confFile->size == fileInfo.size() && confFile->timeStamp == fileInfo.lastModified(QTimeZone::UTC))
            return;
    }
 
    if (!readOnly && !confFile->isWritable()) {
        setStatus(QSettings::AccessError);
        return;
    }
 
#ifndef QT_BOOTSTRAPPED
    QString lockFileName = confFile->name + ".lock"_L1;
 
#    if defined(Q_OS_ANDROID) && defined(QSETTINGS_USE_QSTANDARDPATHS)
    // On android and if it is a content URL put the lock file in a
    // writable location to prevent permissions issues and invalid paths.
    if (confFile->name.startsWith("content:"_L1))
        lockFileName = make_user_path() + QFileInfo(lockFileName).fileName();
#    endif
    /*
        Use a lockfile in order to protect us against other QSettings instances
        trying to write the same settings at the same time.
 
        We only need to lock if we are actually writing as only concurrent writes are a problem.
        Concurrent read and write are not a problem because the writing operation is atomic.
    */
    QLockFile lockFile(lockFileName);
    if (!readOnly && !lockFile.lock() && atomicSyncOnly) {
        setStatus(QSettings::AccessError);
        return;
    }
#endif
 
    /*
        We hold the lock. Let's reread the file if it has changed
        since last time we read it.
    */
    fileInfo.refresh();
    bool mustReadFile = true;
    bool createFile = !fileInfo.exists();
 
    if (!readOnly)
        mustReadFile = (confFile->size != fileInfo.size()
                        || (confFile->size != 0 && confFile->timeStamp != fileInfo.lastModified(QTimeZone::UTC)));
 
    if (mustReadFile) {
        confFile->unparsedIniSections.clear();
        confFile->originalKeys.clear();
 
        QFile file(confFile->name);
        if (!createFile && !file.open(QFile::ReadOnly)) {
            setStatus(QSettings::AccessError);
            return;
        }
 
        /*
            Files that we can't read (because of permissions or
            because they don't exist) are treated as empty files.
        */
        if (file.isReadable() && file.size() != 0) {
            bool ok = false;
#ifdef Q_OS_DARWIN
            if (format == QSettings::NativeFormat) {
                QByteArray data = file.readAll();
                ok = readPlistFile(data, &confFile->originalKeys);
            } else
#endif
            if (format <= QSettings::IniFormat) {
                QByteArray data = file.readAll();
                ok = readIniFile(data, &confFile->unparsedIniSections);
            } else if (readFunc) {
                QSettings::SettingsMap tempNewKeys;
                ok = readFunc(file, tempNewKeys);
 
                if (ok) {
                    auto i = tempNewKeys.constBegin();
                    while (i != tempNewKeys.constEnd()) {
                        confFile->originalKeys.insert(QSettingsKey(i.key(), caseSensitivity),
                                                      i.value());
                        ++i;
                    }
                }
            }
 
            if (!ok)
                setStatus(QSettings::FormatError);
        }
 
        confFile->size = fileInfo.size();
        confFile->timeStamp = fileInfo.lastModified(QTimeZone::UTC);
    }
 
    /*
        We also need to save the file. We still hold the file lock,
        so everything is under control.
    */
    if (!readOnly) {
        bool ok = false;
        ensureAllSectionsParsed(confFile);
        ParsedSettingsMap mergedKeys = confFile->mergedKeyMap();
 
#if !defined(QT_BOOTSTRAPPED) && QT_CONFIG(temporaryfile)
        QSaveFile sf(confFile->name);
        sf.setDirectWriteFallback(!atomicSyncOnly);
#    ifdef Q_OS_ANDROID
        // QSaveFile requires direct write when using content scheme URL in Android
        if (confFile->name.startsWith("content:"_L1))
            sf.setDirectWriteFallback(true);
#    endif
#else
        QFile sf(confFile->name);
#endif
        if (!sf.open(QIODevice::WriteOnly)) {
            setStatus(QSettings::AccessError);
            return;
        }
 
#ifdef Q_OS_DARWIN
        if (format == QSettings::NativeFormat) {
            ok = writePlistFile(sf, mergedKeys);
        } else
#endif
        if (format <= QSettings::IniFormat) {
            ok = writeIniFile(sf, mergedKeys);
        } else if (writeFunc) {
            QSettings::SettingsMap tempOriginalKeys;
 
            auto i = mergedKeys.constBegin();
            while (i != mergedKeys.constEnd()) {
                tempOriginalKeys.insert(i.key(), i.value());
                ++i;
            }
            ok = writeFunc(sf, tempOriginalKeys);
        }
 
#if !defined(QT_BOOTSTRAPPED) && QT_CONFIG(temporaryfile)
        if (ok)
            ok = sf.commit();
#endif
 
        if (ok) {
            confFile->unparsedIniSections.clear();
            confFile->originalKeys = mergedKeys;
            confFile->addedKeys.clear();
            confFile->removedKeys.clear();
 
            fileInfo.refresh();
            confFile->size = fileInfo.size();
            confFile->timeStamp = fileInfo.lastModified(QTimeZone::UTC);
 
            // If we have created the file, apply the file perms
            if (createFile) {
                QFile::Permissions perms = fileInfo.permissions() | QFile::ReadOwner | QFile::WriteOwner;
                if (!confFile->userPerms)
                    perms |= QFile::ReadGroup | QFile::ReadOther;
                QFile(confFile->name).setPermissions(perms);
            }
        } else {
            setStatus(QSettings::AccessError);
        }
    }
}
 
enum { Space = 0x1, Special = 0x2 };
 
static const char charTraits[256] =
{
    // Space: '\t', '\n', '\r', ' '
    // Special: '\n', '\r', '"', ';', '=', '\\'
 
    0, 0, 0, 0, 0, 0, 0, 0, 0, Space, Space | Special, 0, 0, Space | Special, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    Space, 0, Special, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, Special, 0, Special, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, Special, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
 
bool QConfFileSettingsPrivate::readIniLine(QByteArrayView data, qsizetype &dataPos,
                                           qsizetype &lineStart, qsizetype &lineLen,
                                           qsizetype &equalsPos)
{
    qsizetype dataLen = data.size();
    bool inQuotes = false;
 
    equalsPos = -1;
 
    lineStart = dataPos;
    while (lineStart < dataLen && (charTraits[uint(uchar(data.at(lineStart)))] & Space))
        ++lineStart;
 
    qsizetype i = lineStart;
    while (i < dataLen) {
        char ch = data.at(i);
        while (!(charTraits[uchar(ch)] & Special)) {
            if (++i == dataLen)
                goto break_out_of_outer_loop;
            ch = data.at(i);
        }
 
        ++i;
        if (ch == '=') {
            if (!inQuotes && equalsPos == -1)
                equalsPos = i - 1;
        } else if (ch == '\n' || ch == '\r') {
            if (i == lineStart + 1) {
                ++lineStart;
            } else if (!inQuotes) {
                --i;
                goto break_out_of_outer_loop;
            }
        } else if (ch == '\\') {
            if (i < dataLen) {
                char ch = data.at(i++);
                if (i < dataLen) {
                    char ch2 = data.at(i);
                    // \n, \r, \r\n, and \n\r are legitimate line terminators in INI files
                    if ((ch == '\n' && ch2 == '\r') || (ch == '\r' && ch2 == '\n'))
                        ++i;
                }
            }
        } else if (ch == '"') {
            inQuotes = !inQuotes;
        } else {
            Q_ASSERT(ch == ';');
 
            if (i == lineStart + 1) {
                while (i < dataLen && (((ch = data.at(i)) != '\n') && ch != '\r'))
                    ++i;
                while (i < dataLen && charTraits[uchar(data.at(i))] & Space)
                    ++i;
                lineStart = i;
            } else if (!inQuotes) {
                --i;
                goto break_out_of_outer_loop;
            }
        }
    }
 
break_out_of_outer_loop:
    dataPos = i;
    lineLen = i - lineStart;
    return lineLen > 0;
}
 
/*
    Returns \c false on parse error. However, as many keys are read as
    possible, so if the user doesn't check the status he will get the
    most out of the file anyway.
*/
bool QConfFileSettingsPrivate::readIniFile(QByteArrayView data,
                                           UnparsedSettingsMap *unparsedIniSections)
{
#define FLUSH_CURRENT_SECTION() \
    { \
        QByteArray &sectionData = (*unparsedIniSections)[QSettingsKey(currentSection, \
                                                                      IniCaseSensitivity, \
                                                                      sectionPosition)]; \
        if (!sectionData.isEmpty()) \
            sectionData.append('\n'); \
        sectionData += data.first(lineStart).sliced(currentSectionStart); \
        sectionPosition = ++position; \
    }
 
    QString currentSection;
    qsizetype currentSectionStart = 0;
    qsizetype dataPos = 0;
    qsizetype lineStart;
    qsizetype lineLen;
    qsizetype equalsPos;
    qsizetype position = 0;
    qsizetype sectionPosition = 0;
    bool ok = true;
 
    // Skip possible UTF-8 BOM:
    if (data.startsWith("\xef\xbb\xbf"))
        data = data.sliced(3);
 
    while (readIniLine(data, dataPos, lineStart, lineLen, equalsPos)) {
        QByteArrayView line = data.sliced(lineStart, lineLen);
        if (line.startsWith('[')) {
            FLUSH_CURRENT_SECTION();
 
            // This starts a new section.
            qsizetype idx = line.indexOf(']');
            Q_ASSERT(idx == -1 || idx > 0); // line[0] is '[', not ']'.
            Q_ASSERT(idx < lineLen); // (including -1 < lineLen, if no ']' present.)
            if (idx < 0) {
                ok = false;
                idx = lineLen; // so line.first(idx) is just line
            }
            QByteArrayView iniSection = line.first(idx).sliced(1).trimmed();
 
            if (iniSection.compare("general", Qt::CaseInsensitive) == 0) {
                currentSection.clear();
            } else {
                if (iniSection.compare("%general", Qt::CaseInsensitive) == 0) {
                    currentSection = QLatin1StringView(iniSection.constData() + 1, iniSection.size() - 1);
                } else {
                    currentSection.clear();
                    iniUnescapedKey(iniSection, currentSection);
                }
                currentSection += u'/';
            }
            currentSectionStart = dataPos;
        }
        ++position;
    }
 
    Q_ASSERT(lineStart == data.size());
    FLUSH_CURRENT_SECTION();
 
    return ok;
 
#undef FLUSH_CURRENT_SECTION
}
 
bool QConfFileSettingsPrivate::readIniSection(const QSettingsKey &section, QByteArrayView data,
                                              ParsedSettingsMap *settingsMap)
{
    QStringList strListValue;
    bool sectionIsLowercase = (section == section.originalCaseKey());
    qsizetype equalsPos;
 
    bool ok = true;
    qsizetype dataPos = 0;
    qsizetype lineStart;
    qsizetype lineLen;
    qsizetype position = section.originalKeyPosition();
 
    while (readIniLine(data, dataPos, lineStart, lineLen, equalsPos)) {
        QByteArrayView line = data.sliced(lineStart, lineLen);
        Q_ASSERT(!line.startsWith('['));
 
        if (equalsPos == -1) {
            if (!line.startsWith(';'))
                ok = false;
            continue;
        }
        // Shift equalPos indexing to be within line, rather than data:
        equalsPos -= lineStart;
        // Assured by readIniLine:
        Q_ASSERT(equalsPos >= 0 && equalsPos < lineLen);
 
        QByteArrayView key = line.first(equalsPos).trimmed();
        QByteArrayView value = line.sliced(equalsPos + 1);
 
        QString strKey = section.originalCaseKey();
        const Qt::CaseSensitivity casing = iniUnescapedKey(key, strKey) && sectionIsLowercase
                                           ? Qt::CaseSensitive
                                           : IniCaseSensitivity;
 
        QString strValue;
        strValue.reserve(value.size());
        QVariant variant = iniUnescapedStringList(value, strValue, strListValue)
                           ? stringListToVariantList(strListValue)
                           : stringToVariant(strValue);
 
        /*
            We try to avoid the expensive toLower() call in
            QSettingsKey by passing Qt::CaseSensitive when the
            key is already in lowercase.
        */
        settingsMap->insert(QSettingsKey(strKey, casing, position), std::move(variant));
        ++position;
    }
 
    return ok;
}
 
class QSettingsIniKey : public QString
{
public:
    inline QSettingsIniKey() : position(-1) {}
    inline QSettingsIniKey(const QString &str, qsizetype pos = -1) : QString(str), position(pos) {}
 
    qsizetype position;
};
Q_DECLARE_TYPEINFO(QSettingsIniKey, Q_RELOCATABLE_TYPE);
 
static bool operator<(const QSettingsIniKey &k1, const QSettingsIniKey &k2)
{
    if (k1.position != k2.position)
        return k1.position < k2.position;
    return static_cast<const QString &>(k1) < static_cast<const QString &>(k2);
}
 
typedef QMap<QSettingsIniKey, QVariant> IniKeyMap;
 
struct QSettingsIniSection
{
    qsizetype position;
    IniKeyMap keyMap;
 
    inline QSettingsIniSection() : position(-1) {}
};
 
Q_DECLARE_TYPEINFO(QSettingsIniSection, Q_RELOCATABLE_TYPE);
 
typedef QMap<QString, QSettingsIniSection> IniMap;
 
/*
    This would be more straightforward if we didn't try to remember the original
    key order in the .ini file, but we do.
*/
bool QConfFileSettingsPrivate::writeIniFile(QIODevice &device, const ParsedSettingsMap &map)
{
    IniMap iniMap;
 
#ifdef Q_OS_WIN
    const char * const eol = "\r\n";
#else
    const char eol = '\n';
#endif
 
    for (auto j = map.constBegin(); j != map.constEnd(); ++j) {
        QString section;
        QSettingsIniKey key(j.key().originalCaseKey(), j.key().originalKeyPosition());
        qsizetype slashPos;
 
        if ((slashPos = key.indexOf(u'/')) != -1) {
            section = key.left(slashPos);
            key.remove(0, slashPos + 1);
        }
 
        QSettingsIniSection &iniSection = iniMap[section];
 
        // -1 means infinity
        if (size_t(key.position) < size_t(iniSection.position))
            iniSection.position = key.position;
        iniSection.keyMap[key] = j.value();
    }
 
    const qsizetype sectionCount = iniMap.size();
    QList<QSettingsIniKey> sections;
    sections.reserve(sectionCount);
    for (auto i = iniMap.constBegin(); i != iniMap.constEnd(); ++i)
        sections.append(QSettingsIniKey(i.key(), i.value().position));
    std::sort(sections.begin(), sections.end());
 
    bool writeError = false;
    for (qsizetype j = 0; !writeError && j < sectionCount; ++j) {
        auto i = iniMap.constFind(sections.at(j));
        Q_ASSERT(i != iniMap.constEnd());
 
        QByteArray realSection;
 
        iniEscapedKey(i.key(), realSection);
 
        if (realSection.isEmpty()) {
            realSection = "[General]";
        } else if (realSection.compare("general", Qt::CaseInsensitive) == 0) {
            realSection = "[%General]";
        } else {
            realSection.prepend('[');
            realSection.append(']');
        }
 
        if (j != 0)
            realSection.prepend(eol);
        realSection += eol;
 
        device.write(realSection);
 
        const IniKeyMap &ents = i.value().keyMap;
        for (auto j = ents.constBegin(); j != ents.constEnd(); ++j) {
            QByteArray block;
            iniEscapedKey(j.key(), block);
            block += '=';
 
            const QVariant &value = j.value();
 
            /*
                The size() != 1 trick is necessary because
                QVariant(QString("foo")).toList() returns an empty
                list, not a list containing "foo".
            */
            if (value.metaType().id() == QMetaType::QStringList
                    || (value.metaType().id() == QMetaType::QVariantList && value.toList().size() != 1)) {
                iniEscapedStringList(variantListToStringList(value.toList()), block);
            } else {
                iniEscapedString(variantToString(value), block);
            }
            block += eol;
            if (device.write(block) == -1) {
                writeError = true;
                break;
            }
        }
    }
    return !writeError;
}
 
void QConfFileSettingsPrivate::ensureAllSectionsParsed(QConfFile *confFile) const
{
    auto i = confFile->unparsedIniSections.constBegin();
    const auto end = confFile->unparsedIniSections.constEnd();
 
    for (; i != end; ++i) {
        if (!QConfFileSettingsPrivate::readIniSection(i.key(), i.value(), &confFile->originalKeys))
            setStatus(QSettings::FormatError);
    }
    confFile->unparsedIniSections.clear();
}
 
void QConfFileSettingsPrivate::ensureSectionParsed(QConfFile *confFile,
                                                   const QSettingsKey &key) const
{
    if (confFile->unparsedIniSections.isEmpty())
        return;
 
    UnparsedSettingsMap::iterator i;
 
    qsizetype indexOfSlash = key.indexOf(u'/');
    if (indexOfSlash != -1) {
        i = confFile->unparsedIniSections.upperBound(key);
        if (i == confFile->unparsedIniSections.begin())
            return;
        --i;
        if (i.key().isEmpty() || !key.startsWith(i.key()))
            return;
    } else {
        i = confFile->unparsedIniSections.begin();
        if (i == confFile->unparsedIniSections.end() || !i.key().isEmpty())
            return;
    }
 
    if (!QConfFileSettingsPrivate::readIniSection(i.key(), i.value(), &confFile->originalKeys))
        setStatus(QSettings::FormatError);
    confFile->unparsedIniSections.erase(i);
}
 
#ifndef QT_NO_QOBJECT
QSettings::QSettings(const QString &organization, const QString &application, QObject *parent)
    : QObject(*QSettingsPrivate::create(NativeFormat, UserScope, organization, application),
              parent)
{
}
 
QSettings::QSettings(Scope scope, const QString &organization, const QString &application,
                     QObject *parent)
    : QObject(*QSettingsPrivate::create(NativeFormat, scope, organization, application), parent)
{
}
 
QSettings::QSettings(Format format, Scope scope, const QString &organization,
                     const QString &application, QObject *parent)
    : QObject(*QSettingsPrivate::create(format, scope, organization, application), parent)
{
}
 
QSettings::QSettings(const QString &fileName, Format format, QObject *parent)
    : QObject(*QSettingsPrivate::create(fileName, format), parent)
{
}
 
QSettings::QSettings(QObject *parent)
    : QSettings(UserScope, parent)
{
}
 
QSettings::QSettings(Scope scope, QObject *parent)
    : QObject(*QSettingsPrivate::create(globalDefaultFormat, scope,
#ifdef Q_OS_DARWIN
                                        QCoreApplication::organizationDomain().isEmpty()
                                            ? QCoreApplication::organizationName()
                                            : QCoreApplication::organizationDomain()
#else
                                        QCoreApplication::organizationName().isEmpty()
                                            ? QCoreApplication::organizationDomain()
                                            : QCoreApplication::organizationName()
#endif
                                        , QCoreApplication::applicationName()),
              parent)
{
}
 
#else
QSettings::QSettings(const QString &organization, const QString &application)
    : d_ptr(QSettingsPrivate::create(globalDefaultFormat, QSettings::UserScope, organization, application))
{
    d_ptr->q_ptr = this;
}
 
QSettings::QSettings(Scope scope, const QString &organization, const QString &application)
    : d_ptr(QSettingsPrivate::create(globalDefaultFormat, scope, organization, application))
{
    d_ptr->q_ptr = this;
}
 
QSettings::QSettings(Format format, Scope scope, const QString &organization,
                     const QString &application)
    : d_ptr(QSettingsPrivate::create(format, scope, organization, application))
{
    d_ptr->q_ptr = this;
}
 
QSettings::QSettings(const QString &fileName, Format format)
    : d_ptr(QSettingsPrivate::create(fileName, format))
{
    d_ptr->q_ptr = this;
}
 
QSettings::QSettings(Scope scope)
    : d_ptr(QSettingsPrivate::create(globalDefaultFormat, scope,
#  ifdef Q_OS_DARWIN
                                     QCoreApplication::organizationDomain().isEmpty()
                                         ? QCoreApplication::organizationName()
                                         : QCoreApplication::organizationDomain()
#  else
                                     QCoreApplication::organizationName().isEmpty()
                                         ? QCoreApplication::organizationDomain()
                                         : QCoreApplication::organizationName()
#  endif
                                     , QCoreApplication::applicationName())
              )
{
    d_ptr->q_ptr = this;
}
#endif
 
QSettings::~QSettings()
{
    Q_D(QSettings);
    if (d->pendingChanges) {
        // Don't cause a failing flush() to std::terminate() the whole
        // application - dtors are implicitly noexcept!
        QT_TRY {
            d->flush();
        } QT_CATCH(...) {
        }
    }
}
 
void QSettings::clear()
{
    Q_D(QSettings);
    d->clear();
    d->requestUpdate();
}
 
void QSettings::sync()
{
    Q_D(QSettings);
    d->sync();
    d->pendingChanges = false;
}
 
QString QSettings::fileName() const
{
    Q_D(const QSettings);
    return d->fileName();
}
 
QSettings::Format QSettings::format() const
{
    Q_D(const QSettings);
    return d->format;
}
 
QSettings::Scope QSettings::scope() const
{
    Q_D(const QSettings);
    return d->scope;
}
 
QString QSettings::organizationName() const
{
    Q_D(const QSettings);
    return d->organizationName;
}
 
QString QSettings::applicationName() const
{
    Q_D(const QSettings);
    return d->applicationName;
}
 
QSettings::Status QSettings::status() const
{
    Q_D(const QSettings);
    return d->status;
}
 
bool QSettings::isAtomicSyncRequired() const
{
    Q_D(const QSettings);
    return d->atomicSyncOnly;
}
 
void QSettings::setAtomicSyncRequired(bool enable)
{
    Q_D(QSettings);
    d->atomicSyncOnly = enable;
}
 
void QSettings::beginGroup(QAnyStringView prefix)
{
    Q_D(QSettings);
    d->beginGroupOrArray(QSettingsGroup(d->normalizedKey(prefix)));
}
 
void QSettings::endGroup()
{
    Q_D(QSettings);
    if (d->groupStack.isEmpty()) {
        qWarning("QSettings::endGroup: No matching beginGroup()");
        return;
    }
 
    QSettingsGroup group = d->groupStack.pop();
    qsizetype len = group.toString().size();
    if (len > 0)
        d->groupPrefix.truncate(d->groupPrefix.size() - (len + 1));
 
    if (group.isArray())
        qWarning("QSettings::endGroup: Expected endArray() instead");
}
 
QString QSettings::group() const
{
    Q_D(const QSettings);
    return d->groupPrefix.left(d->groupPrefix.size() - 1);
}
 
int QSettings::beginReadArray(QAnyStringView prefix)
{
    Q_D(QSettings);
    d->beginGroupOrArray(QSettingsGroup(d->normalizedKey(prefix), false));
    return value("size"_L1).toInt();
}
 
void QSettings::beginWriteArray(QAnyStringView prefix, int size)
{
    Q_D(QSettings);
    d->beginGroupOrArray(QSettingsGroup(d->normalizedKey(prefix), size < 0));
 
    if (size < 0)
        remove("size"_L1);
    else
        setValue("size"_L1, size);
}
 
void QSettings::endArray()
{
    Q_D(QSettings);
    if (d->groupStack.isEmpty()) {
        qWarning("QSettings::endArray: No matching beginArray()");
        return;
    }
 
    QSettingsGroup group = d->groupStack.top();
    qsizetype len = group.toString().size();
    d->groupStack.pop();
    if (len > 0)
        d->groupPrefix.truncate(d->groupPrefix.size() - (len + 1));
 
    if (group.arraySizeGuess() != -1)
        setValue(group.name() + "/size"_L1, group.arraySizeGuess());
 
    if (!group.isArray())
        qWarning("QSettings::endArray: Expected endGroup() instead");
}
 
void QSettings::setArrayIndex(int i)
{
    Q_D(QSettings);
    if (d->groupStack.isEmpty() || !d->groupStack.top().isArray()) {
        qWarning("QSettings::setArrayIndex: Missing beginArray()");
        return;
    }
 
    QSettingsGroup &top = d->groupStack.top();
    qsizetype len = top.toString().size();
    top.setArrayIndex(qMax(i, 0));
    d->groupPrefix.replace(d->groupPrefix.size() - len - 1, len, top.toString());
}
 
QStringList QSettings::allKeys() const
{
    Q_D(const QSettings);
    return d->children(d->groupPrefix, QSettingsPrivate::AllKeys);
}
 
QStringList QSettings::childKeys() const
{
    Q_D(const QSettings);
    return d->children(d->groupPrefix, QSettingsPrivate::ChildKeys);
}
 
QStringList QSettings::childGroups() const
{
    Q_D(const QSettings);
    return d->children(d->groupPrefix, QSettingsPrivate::ChildGroups);
}
 
bool QSettings::isWritable() const
{
    Q_D(const QSettings);
    return d->isWritable();
}
 
void QSettings::setValue(QAnyStringView key, const QVariant &value)
{
    Q_D(QSettings);
    if (key.isEmpty()) {
        qWarning("QSettings::setValue: Empty key passed");
        return;
    }
    d->set(d->actualKey(key), value);
    d->requestUpdate();
}
 
void QSettings::remove(QAnyStringView key)
{
    Q_D(QSettings);
    /*
        We cannot use actualKey(), because remove() supports empty
        keys. The code is also tricky because of slash handling.
    */
    QString theKey = d->normalizedKey(key);
    if (theKey.isEmpty())
        theKey = group();
    else
        theKey.prepend(d->groupPrefix);
 
    if (theKey.isEmpty()) {
        d->clear();
    } else {
        d->remove(theKey);
    }
    d->requestUpdate();
}
 
bool QSettings::contains(QAnyStringView key) const
{
    Q_D(const QSettings);
    return d->get(d->actualKey(key)) != std::nullopt;
}
 
void QSettings::setFallbacksEnabled(bool b)
{
    Q_D(QSettings);
    d->fallbacks = !!b;
}
 
bool QSettings::fallbacksEnabled() const
{
    Q_D(const QSettings);
    return d->fallbacks;
}
 
#ifndef QT_NO_QOBJECT
bool QSettings::event(QEvent *event)
{
    Q_D(QSettings);
    if (event->type() == QEvent::UpdateRequest) {
        d->update();
        return true;
    }
    return QObject::event(event);
}
#endif
 
QVariant QSettings::value(QAnyStringView key) const
{
    Q_D(const QSettings);
    return d->value(key, nullptr);
}
 
QVariant QSettings::value(QAnyStringView key, const QVariant &defaultValue) const
{
    Q_D(const QSettings);
    return d->value(key, &defaultValue);
}
 
QVariant QSettingsPrivate::value(QAnyStringView key, const QVariant *defaultValue) const
{
    if (key.isEmpty()) {
        qWarning("QSettings::value: Empty key passed");
        return QVariant();
    }
    if (std::optional r = get(actualKey(key)))
        return std::move(*r);
    if (defaultValue)
        return *defaultValue;
    return QVariant();
}
 
void QSettings::setDefaultFormat(Format format)
{
    globalDefaultFormat = format;
}
 
QSettings::Format QSettings::defaultFormat()
{
    return globalDefaultFormat;
}
 
void QSettings::setPath(Format format, Scope scope, const QString &path)
{
    auto locker = qt_unique_lock(settingsGlobalMutex);
    PathHash *pathHash = pathHashFunc();
    if (pathHash->isEmpty())
        locker = initDefaultPaths(std::move(locker));
    pathHash->insert(pathHashKey(format, scope), Path(path + QDir::separator(), true));
}
 
QSettings::Format QSettings::registerFormat(const QString &extension, ReadFunc readFunc,
                                            WriteFunc writeFunc,
                                            Qt::CaseSensitivity caseSensitivity)
{
#ifdef QT_QSETTINGS_ALWAYS_CASE_SENSITIVE_AND_FORGET_ORIGINAL_KEY_ORDER
    Q_ASSERT(caseSensitivity == Qt::CaseSensitive);
#endif
 
    const auto locker = qt_scoped_lock(settingsGlobalMutex);
    CustomFormatVector *customFormatVector = customFormatVectorFunc();
    qsizetype index = customFormatVector->size();
    if (index == 16) // the QSettings::Format enum has room for 16 custom formats
        return QSettings::InvalidFormat;
 
    QConfFileCustomFormat info;
    info.extension = u'.' + extension;
    info.readFunc = readFunc;
    info.writeFunc = writeFunc;
    info.caseSensitivity = caseSensitivity;
    customFormatVector->append(info);
 
    return QSettings::Format(int(QSettings::CustomFormat1) + index);
}
 
QT_END_NAMESPACE
 
#ifndef QT_BOOTSTRAPPED
#include "moc_qsettings.cpp"
#endif