qsystemlibrary.cpp

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// Copyright (C) 2016 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 "qsystemlibrary_p.h"
#include <QtCore/qvarlengtharray.h>
#include <QtCore/qstringlist.h>
#include <QtCore/qfileinfo.h>
 
QT_BEGIN_NAMESPACE
 
using namespace Qt::StringLiterals;
 
#if !defined(QT_BOOTSTRAPPED)
extern QString qAppFileName();
#endif
 
static QString qSystemDirectory()
{
    static const QString result = []() -> QString {
        QVarLengthArray<wchar_t, MAX_PATH> fullPath = {};
        UINT retLen = ::GetSystemDirectoryW(fullPath.data(), MAX_PATH);
        if (retLen > MAX_PATH) {
            fullPath.resize(retLen);
            retLen = ::GetSystemDirectoryW(fullPath.data(), retLen);
        }
        // in some rare cases retLen might be 0
        return QString::fromWCharArray(fullPath.constData(), int(retLen));
    }();
    return result;
}
 
HINSTANCE QSystemLibrary::load(const wchar_t *libraryName, bool onlySystemDirectory /* = true */)
{
    if (onlySystemDirectory)
        return ::LoadLibraryExW(libraryName, nullptr, LOAD_LIBRARY_SEARCH_SYSTEM32);
 
    QStringList searchOrder;
 
#if !defined(QT_BOOTSTRAPPED)
    searchOrder << QFileInfo(qAppFileName()).path();
#endif
    searchOrder << qSystemDirectory();
 
    const QString PATH(QLatin1StringView(qgetenv("PATH")));
    searchOrder << PATH.split(u';', Qt::SkipEmptyParts);
 
    const QString fileName = QString::fromWCharArray(libraryName);
 
    // Start looking in the order specified
    for (int i = 0; i < searchOrder.count(); ++i) {
        QString fullPathAttempt = searchOrder.at(i);
        if (!fullPathAttempt.endsWith(u'\\')) {
            fullPathAttempt.append(u'\\');
        }
        fullPathAttempt.append(fileName);
        HINSTANCE inst = ::LoadLibrary(reinterpret_cast<const wchar_t *>(fullPathAttempt.utf16()));
        if (inst != nullptr)
            return inst;
    }
    return nullptr;
}
 
QT_END_NAMESPACE