/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** 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
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qfilesystementry_p.h"

#include <QtCore/qdir.h>
#include <QtCore/qfile.h>
#include <QtCore/private/qfsfileengine_p.h>
#ifdef Q_OS_WIN
#include <QtCore/qstringbuilder.h>
#endif

QT_BEGIN_NAMESPACE

#ifdef Q_OS_WIN
static bool isUncRoot(const QString &server)
{
    QString localPath = QDir::toNativeSeparators(server);
    if (!localPath.startsWith(QLatin1String("\\\\")))
        return false;

    int idx = localPath.indexOf(QLatin1Char('\\'), 2);
    if (idx == -1 || idx + 1 == localPath.length())
        return true;

    return localPath.rightRef(localPath.length() - idx - 1).trimmed().isEmpty();
}

static inline QString fixIfRelativeUncPath(const QString &path)
{
    QString currentPath = QDir::currentPath();
    if (currentPath.startsWith(QLatin1String("//")))
        return currentPath % QChar(QLatin1Char('/')) % path;
    return path;
}
#endif

QFileSystemEntry::QFileSystemEntry()
    : m_lastSeparator(-1),
    m_firstDotInFileName(-1),
    m_lastDotInFileName(-1)
{
}

/*!
   \internal
   Use this constructor when the path is supplied by user code, as it may contain a mix
   of '/' and the native separator.
 */
QFileSystemEntry::QFileSystemEntry(const QString &filePath)
    : m_filePath(QDir::fromNativeSeparators(filePath)),
    m_lastSeparator(-2),
    m_firstDotInFileName(-2),
    m_lastDotInFileName(0)
{
}

/*!
   \internal
   Use this constructor when the path is guaranteed to be in internal format, i.e. all
   directory separators are '/' and not the native separator.
 */
QFileSystemEntry::QFileSystemEntry(const QString &filePath, FromInternalPath /* dummy */)
    : m_filePath(filePath),
    m_lastSeparator(-2),
    m_firstDotInFileName(-2),
    m_lastDotInFileName(0)
{
}

/*!
   \internal
   Use this constructor when the path comes from a native API
 */
QFileSystemEntry::QFileSystemEntry(const NativePath &nativeFilePath, FromNativePath /* dummy */)
    : m_nativeFilePath(nativeFilePath),
    m_lastSeparator(-2),
    m_firstDotInFileName(-2),
    m_lastDotInFileName(0)
{
}

QFileSystemEntry::QFileSystemEntry(const QString &filePath, const NativePath &nativeFilePath)
    : m_filePath(QDir::fromNativeSeparators(filePath)),
    m_nativeFilePath(nativeFilePath),
    m_lastSeparator(-2),
    m_firstDotInFileName(-2),
    m_lastDotInFileName(0)
{
}

QString QFileSystemEntry::filePath() const
{
    resolveFilePath();
    return m_filePath;
}

QFileSystemEntry::NativePath QFileSystemEntry::nativeFilePath() const
{
    resolveNativeFilePath();
    return m_nativeFilePath;
}

void QFileSystemEntry::resolveFilePath() const
{
    if (m_filePath.isEmpty() && !m_nativeFilePath.isEmpty()) {
#if defined(QFILESYSTEMENTRY_NATIVE_PATH_IS_UTF16)
        m_filePath = QDir::fromNativeSeparators(m_nativeFilePath);
#ifdef Q_OS_WIN
        if (m_filePath.startsWith(QLatin1String("//?/UNC/")))
            m_filePath = m_filePath.remove(2,6);
        if (m_filePath.startsWith(QLatin1String("//?/")))
            m_filePath = m_filePath.remove(0,4);
#endif
#else
        m_filePath = QDir::fromNativeSeparators(QFile::decodeName(m_nativeFilePath));
#endif
    }
}

void QFileSystemEntry::resolveNativeFilePath() const
{
    if (!m_filePath.isEmpty() && m_nativeFilePath.isEmpty()) {
#ifdef Q_OS_WIN
        QString filePath = m_filePath;
        if (isRelative())
            filePath = fixIfRelativeUncPath(m_filePath);
        m_nativeFilePath = QFSFileEnginePrivate::longFileName(QDir::toNativeSeparators(filePath));
#elif defined(QFILESYSTEMENTRY_NATIVE_PATH_IS_UTF16)
        m_nativeFilePath = QDir::toNativeSeparators(m_filePath);
#else
        m_nativeFilePath = QFile::encodeName(QDir::toNativeSeparators(m_filePath));
#endif
#ifdef Q_OS_WINRT
        while (m_nativeFilePath.startsWith(QLatin1Char('\\')))
            m_nativeFilePath.remove(0,1);
        if (m_nativeFilePath.isEmpty())
            m_nativeFilePath.append(QLatin1Char('.'));
        // WinRT/MSVC2015 allows a maximum of 256 characters for a filepath
        // unless //?/ is prepended which extends the rule to have a maximum
        // of 256 characters in the filename plus the preprending path
        m_nativeFilePath.prepend("\\\\?\\");
#endif
    }
}

QString QFileSystemEntry::fileName() const
{
    findLastSeparator();
#if defined(Q_OS_WIN)
    if (m_lastSeparator == -1 && m_filePath.length() >= 2 && m_filePath.at(1) == QLatin1Char(':'))
        return m_filePath.mid(2);
#endif
    return m_filePath.mid(m_lastSeparator + 1);
}

QString QFileSystemEntry::path() const
{
    findLastSeparator();
    if (m_lastSeparator == -1) {
#if defined(Q_OS_WIN)
        if (m_filePath.length() >= 2 && m_filePath.at(1) == QLatin1Char(':'))
            return m_filePath.left(2);
#endif
        return QString(QLatin1Char('.'));
    }
    if (m_lastSeparator == 0)
        return QString(QLatin1Char('/'));
#if defined(Q_OS_WIN)
    if (m_lastSeparator == 2 && m_filePath.at(1) == QLatin1Char(':'))
        return m_filePath.left(m_lastSeparator + 1);
#endif
    return m_filePath.left(m_lastSeparator);
}

QString QFileSystemEntry::baseName() const
{
    findFileNameSeparators();
    int length = -1;
    if (m_firstDotInFileName >= 0) {
        length = m_firstDotInFileName;
        if (m_lastSeparator != -1) // avoid off by one
            length--;
    }
#if defined(Q_OS_WIN)
    if (m_lastSeparator == -1 && m_filePath.length() >= 2 && m_filePath.at(1) == QLatin1Char(':'))
        return m_filePath.mid(2, length - 2);
#endif
    return m_filePath.mid(m_lastSeparator + 1, length);
}

QString QFileSystemEntry::completeBaseName() const
{
    findFileNameSeparators();
    int length = -1;
    if (m_firstDotInFileName >= 0) {
        length = m_firstDotInFileName + m_lastDotInFileName;
        if (m_lastSeparator != -1) // avoid off by one
            length--;
    }
#if defined(Q_OS_WIN)
    if (m_lastSeparator == -1 && m_filePath.length() >= 2 && m_filePath.at(1) == QLatin1Char(':'))
        return m_filePath.mid(2, length - 2);
#endif
    return m_filePath.mid(m_lastSeparator + 1, length);
}

QString QFileSystemEntry::suffix() const
{
    findFileNameSeparators();

    if (m_lastDotInFileName == -1)
        return QString();

    return m_filePath.mid(qMax((qint16)0, m_lastSeparator) + m_firstDotInFileName + m_lastDotInFileName + 1);
}

QString QFileSystemEntry::completeSuffix() const
{
    findFileNameSeparators();
    if (m_firstDotInFileName == -1)
        return QString();

    return m_filePath.mid(qMax((qint16)0, m_lastSeparator) + m_firstDotInFileName + 1);
}

#if defined(Q_OS_WIN)
bool QFileSystemEntry::isRelative() const
{
    resolveFilePath();
    return (m_filePath.isEmpty()
            || (m_filePath.at(0).unicode() != '/'
                && !(m_filePath.length() >= 2 && m_filePath.at(1).unicode() == ':')));
}

bool QFileSystemEntry::isAbsolute() const
{
    resolveFilePath();
    return ((m_filePath.length() >= 3
             && m_filePath.at(0).isLetter()
             && m_filePath.at(1).unicode() == ':'
             && m_filePath.at(2).unicode() == '/')
         || (m_filePath.length() >= 2
             && m_filePath.at(0) == QLatin1Char('/')
             && m_filePath.at(1) == QLatin1Char('/')));
}
#else
bool QFileSystemEntry::isRelative() const
{
    return !isAbsolute();
}

bool QFileSystemEntry::isAbsolute() const
{
    resolveFilePath();
    return (!m_filePath.isEmpty() && (m_filePath.at(0).unicode() == '/'));
}
#endif

#if defined(Q_OS_WIN)
bool QFileSystemEntry::isDriveRoot() const
{
    resolveFilePath();
    return QFileSystemEntry::isDriveRootPath(m_filePath);
}

bool QFileSystemEntry::isDriveRootPath(const QString &path)
{
#ifndef Q_OS_WINRT
    return (path.length() == 3
           && path.at(0).isLetter() && path.at(1) == QLatin1Char(':')
           && path.at(2) == QLatin1Char('/'));
#else // !Q_OS_WINRT
    return path == QDir::rootPath();
#endif // !Q_OS_WINRT
}
#endif // Q_OS_WIN

bool QFileSystemEntry::isRootPath(const QString &path)
{
    if (path == QLatin1String("/")
#if defined(Q_OS_WIN)
            || isDriveRootPath(path)
            || isUncRoot(path)
#endif
            )
        return true;

    return false;
}

bool QFileSystemEntry::isRoot() const
{
    resolveFilePath();
    return isRootPath(m_filePath);
}

// private methods

void QFileSystemEntry::findLastSeparator() const
{
    if (m_lastSeparator == -2) {
        resolveFilePath();
        m_lastSeparator = m_filePath.lastIndexOf(QLatin1Char('/'));
    }
}

void QFileSystemEntry::findFileNameSeparators() const
{
    if (m_firstDotInFileName == -2) {
        resolveFilePath();
        int firstDotInFileName = -1;
        int lastDotInFileName = -1;
        int lastSeparator = m_lastSeparator;

        int stop;
        if (lastSeparator < 0) {
            lastSeparator = -1;
            stop = 0;
        } else {
            stop = lastSeparator;
        }

        int i = m_filePath.size() - 1;
        for (; i >= stop; --i) {
            if (m_filePath.at(i).unicode() == '.') {
                firstDotInFileName = lastDotInFileName = i;
                break;
            } else if (m_filePath.at(i).unicode() == '/') {
                lastSeparator = i;
                break;
            }
        }

        if (lastSeparator != i) {
            for (--i; i >= stop; --i) {
                if (m_filePath.at(i).unicode() == '.')
                    firstDotInFileName = i;
                else if (m_filePath.at(i).unicode() == '/') {
                    lastSeparator = i;
                    break;
                }
            }
        }
        m_lastSeparator = lastSeparator;
        m_firstDotInFileName = firstDotInFileName == -1 ? -1 : firstDotInFileName - qMax(0, lastSeparator);
        if (lastDotInFileName == -1)
            m_lastDotInFileName = -1;
        else if (firstDotInFileName == lastDotInFileName)
            m_lastDotInFileName = 0;
        else
            m_lastDotInFileName = lastDotInFileName - firstDotInFileName;
    }
}

bool QFileSystemEntry::isClean() const
{
    resolveFilePath();
    int dots = 0;
    bool dotok = true; // checking for ".." or "." starts to relative paths
    bool slashok = true;
    for (QString::const_iterator iter = m_filePath.constBegin(); iter != m_filePath.constEnd(); ++iter) {
        if (*iter == QLatin1Char('/')) {
            if (dots == 1 || dots == 2)
                return false; // path contains "./" or "../"
            if (!slashok)
                return false; // path contains "//"
            dots = 0;
            dotok = true;
            slashok = false;
        } else if (dotok) {
            slashok = true;
            if (*iter == QLatin1Char('.')) {
                dots++;
                if (dots > 2)
                    dotok = false;
            } else {
                //path element contains a character other than '.', it's clean
                dots = 0;
                dotok = false;
            }
        }
    }
    return (dots != 1 && dots != 2); // clean if path doesn't end in . or ..
}

QT_END_NAMESPACE