/****************************************************************************

**

** Copyright (C) 2016 The Qt Company Ltd.

** Copyright (C) 2018 Intel Corporation.

** 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.

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** $QT_END_LICENSE$

**

****************************************************************************/

#include "qplatformdefs.h"

#include "qlibrary.h"

#include "qfactoryloader_p.h"

#include "qlibrary_p.h"

#include <qstringlist.h>

#include <qfile.h>

#include <qfileinfo.h>

#include <qmutex.h>

#include <qmap.h>

#include <private/qcoreapplication_p.h>

#include <private/qsystemerror_p.h>

#ifdef Q_OS_MAC

#  include <private/qcore_mac_p.h>

#endif

#ifndef NO_ERRNO_H

#include <errno.h>

#endif // NO_ERROR_H

#include <qdebug.h>

#include <qvector.h>

#include <qdir.h>

#include <qendian.h>

#include <qjsondocument.h>

#include <qjsonvalue.h>

#include "qelfparser_p.h"

#include "qmachparser_p.h"

#include <qtcore_tracepoints_p.h>

QT_BEGIN_NAMESPACE

#ifdef QT_NO_DEBUG

#  define QLIBRARY_AS_DEBUG false

#else

#  define QLIBRARY_AS_DEBUG true

#endif

#if defined(Q_OS_UNIX) || (defined(Q_CC_MINGW) && !QT_CONFIG(debug_and_release))

// We don't use separate debug and release libs on UNIX, so we want

// to allow loading plugins, regardless of how they were built.

#  define QT_NO_DEBUG_PLUGIN_CHECK

#endif

/*!

    \class QLibrary

    \inmodule QtCore

    \reentrant

    \brief The QLibrary class loads shared libraries at runtime.

    \ingroup plugins

    An instance of a QLibrary object operates on a single shared

    object file (which we call a "library", but is also known as a

    "DLL"). A QLibrary provides access to the functionality in the

    library in a platform independent way. You can either pass a file

    name in the constructor, or set it explicitly with setFileName().

    When loading the library, QLibrary searches in all the

    system-specific library locations (e.g. \c LD_LIBRARY_PATH on

    Unix), unless the file name has an absolute path.

    If the file name is an absolute path then an attempt is made to

    load this path first. If the file cannot be found, QLibrary tries

    the name with different platform-specific file prefixes, like

    "lib" on Unix and Mac, and suffixes, like ".so" on Unix, ".dylib"

    on the Mac, or ".dll" on Windows.

    If the file path is not absolute then QLibrary modifies the search

    order to try the system-specific prefixes and suffixes first,

    followed by the file path specified.

    This makes it possible to specify shared libraries that are only

    identified by their basename (i.e. without their suffix), so the

    same code will work on different operating systems yet still

    minimise the number of attempts to find the library.

    The most important functions are load() to dynamically load the

    library file, isLoaded() to check whether loading was successful,

    and resolve() to resolve a symbol in the library. The resolve()

    function implicitly tries to load the library if it has not been

    loaded yet. Multiple instances of QLibrary can be used to access

    the same physical library. Once loaded, libraries remain in memory

    until the application terminates. You can attempt to unload a

    library using unload(), but if other instances of QLibrary are

    using the same library, the call will fail, and unloading will

    only happen when every instance has called unload().

    A typical use of QLibrary is to resolve an exported symbol in a

    library, and to call the C function that this symbol represents.

    This is called "explicit linking" in contrast to "implicit

    linking", which is done by the link step in the build process when

    linking an executable against a library.

    The following code snippet loads a library, resolves the symbol

    "mysymbol", and calls the function if everything succeeded. If

    something goes wrong, e.g. the library file does not exist or the

    symbol is not defined, the function pointer will be \nullptr and

    won't be called.

    \snippet code/src_corelib_plugin_qlibrary.cpp 0

    The symbol must be exported as a C function from the library for

    resolve() to work. This means that the function must be wrapped in

    an \c{extern "C"} block if the library is compiled with a C++

    compiler. On Windows, this also requires the use of a \c dllexport

    macro; see resolve() for the details of how this is done. For

    convenience, there is a static resolve() function which you can

    use if you just want to call a function in a library without

    explicitly loading the library first:

    \snippet code/src_corelib_plugin_qlibrary.cpp 1

    \sa QPluginLoader

*/

/*!

    \enum QLibrary::LoadHint

    This enum describes the possible hints that can be used to change the way

    libraries are handled when they are loaded. These values indicate how

    symbols are resolved when libraries are loaded, and are specified using

    the setLoadHints() function.

    \value ResolveAllSymbolsHint

    Causes all symbols in a library to be resolved when it is loaded, not

    simply when resolve() is called.

    \value ExportExternalSymbolsHint

    Exports unresolved and external symbols in the library so that they can be

    resolved in other dynamically-loaded libraries loaded later.

    \value LoadArchiveMemberHint

    Allows the file name of the library to specify a particular object file

    within an archive file.

    If this hint is given, the filename of the library consists of

    a path, which is a reference to an archive file, followed by

    a reference to the archive member.

    \value PreventUnloadHint

    Prevents the library from being unloaded from the address space if close()

    is called. The library's static variables are not reinitialized if open()

    is called at a later time.

    \value DeepBindHint

    Instructs the linker to prefer definitions in the loaded library

    over exported definitions in the loading application when resolving

    external symbols in the loaded library. This option is only supported

    on Linux.

    \sa loadHints

*/

static qsizetype qt_find_pattern(const char *s, qsizetype s_len,

                             const char *pattern, ulong p_len)

{

    /*

      we search from the end of the file because on the supported

      systems, the read-only data/text segments are placed at the end

      of the file.  HOWEVER, when building with debugging enabled, all

      the debug symbols are placed AFTER the data/text segments.

      what does this mean?  when building in release mode, the search

      is fast because the data we are looking for is at the end of the

      file... when building in debug mode, the search is slower

      because we have to skip over all the debugging symbols first

    */

    if (!s || !pattern || qsizetype(p_len) > s_len)

        return -1;

    size_t i, hs = 0, hp = 0, delta = s_len - p_len;

    for (i = 0; i < p_len; ++i) {

        hs += s[delta + i];

        hp += pattern[i];

    }

    i = delta;

    for (;;) {

        if (hs == hp && qstrncmp(s + i, pattern, p_len) == 0)

            return i;   // can't overflow, by construction

        if (i == 0)

            break;

        --i;

        hs -= s[i + p_len];

        hs += s[i];

    }

    return -1;

}

/*

  This opens the specified library, mmaps it into memory, and searches

  for the QT_PLUGIN_VERIFICATION_DATA.  The advantage of this approach is that

  we can get the verification data without have to actually load the library.

  This lets us detect mismatches more safely.

  Returns \c false if version information is not present, or if the

                information could not be read.

  Returns  true if version information is present and successfully read.

*/

static bool findPatternUnloaded(const QString &library, QLibraryPrivate *lib)

{

    QFile file(library);

    if (!file.open(QIODevice::ReadOnly)) {

        if (lib)

            lib->errorString = file.errorString();

        if (qt_debug_component()) {

            qWarning("%s: %ls", QFile::encodeName(library).constData(),

                     qUtf16Printable(QSystemError::stdString()));

        }

        return false;

    }

    // Files can be bigger than the virtual memory size on 32-bit systems, so

    // we limit to 512 MB there. For 64-bit, we allow up to 2^40 bytes.

    constexpr qint64 MaxMemoryMapSize =

            Q_INT64_C(1) << (sizeof(qsizetype) > 4 ? 40 : 29);

    QByteArray data;

    qsizetype fdlen = qMin(file.size(), MaxMemoryMapSize);

    const char *filedata = reinterpret_cast<char *>(file.map(0, fdlen));

    if (filedata == nullptr) {

        // Try reading the data into memory instead (up to 64 MB).

        data = file.read(64 * 1024 * 1024);

        filedata = data.constData();

        fdlen = data.size();

    }

    /*

       ELF and Mach-O binaries with GCC have .qplugin sections.

    */

    bool hasMetaData = false;

    qsizetype pos = 0;

    char pattern[] = "qTMETADATA ";

    pattern[0] = 'Q'; // Ensure the pattern "QTMETADATA" is not found in this library should QPluginLoader ever encounter it.

    const ulong plen = qstrlen(pattern);

#if defined (Q_OF_ELF) && defined(Q_CC_GNU)

    int r = QElfParser().parse(filedata, fdlen, library, lib, &pos, &fdlen);

    if (r == QElfParser::Corrupt || r == QElfParser::NotElf) {

            if (lib && qt_debug_component()) {

                qWarning("QElfParser: %ls", qUtf16Printable(lib->errorString));

            }

            return false;

    } else if (r == QElfParser::QtMetaDataSection) {

        qsizetype rel = qt_find_pattern(filedata + pos, fdlen, pattern, plen);

        if (rel < 0)

            pos = -1;

        else

            pos += rel;

        hasMetaData = true;

    }

#elif defined (Q_OF_MACH_O)

    {

        QString errorString;

        int r = QMachOParser::parse(filedata, fdlen, library, &errorString, &pos, &fdlen);

        if (r == QMachOParser::NotSuitable) {

            if (qt_debug_component())

                qWarning("QMachOParser: %ls", qUtf16Printable(errorString));

            if (lib)

                lib->errorString = errorString;

            return false;

        }

        // even if the metadata section was not found, the Mach-O parser will

        // at least return the boundaries of the right architecture

        qsizetype rel = qt_find_pattern(filedata + pos, fdlen, pattern, plen);

        if (rel < 0)

            pos = -1;

        else

            pos += rel;

        hasMetaData = true;

    }

#else

    pos = qt_find_pattern(filedata, fdlen, pattern, plen);

    if (pos > 0)

        hasMetaData = true;

#endif // defined(Q_OF_ELF) && defined(Q_CC_GNU)

    bool ret = false;

    if (pos >= 0 && hasMetaData) {

        const char *data = filedata + pos;

        QString errMsg;

        QJsonDocument doc = qJsonFromRawLibraryMetaData(data, fdlen, &errMsg);

        if (doc.isNull()) {

            qWarning("Found invalid metadata in lib %ls: %ls",

                     qUtf16Printable(library), qUtf16Printable(errMsg));

        } else {

            lib->metaData = doc.object();

            if (qt_debug_component())

                qWarning("Found metadata in lib %s, metadata=\n%s\n",

                         library.toLocal8Bit().constData(), doc.toJson().constData());

            ret = !doc.isNull();

        }

    }

    if (!ret && lib)

        lib->errorString = QLibrary::tr("Failed to extract plugin meta data from '%1'").arg(library);

    file.close();

    return ret;

}

static void installCoverageTool(QLibraryPrivate *libPrivate)

{

#ifdef __COVERAGESCANNER__

    /*

      __COVERAGESCANNER__ is defined when Qt has been instrumented for code

      coverage by TestCocoon. CoverageScanner is the name of the tool that

      generates the code instrumentation.

      This code is required here when code coverage analysis with TestCocoon

      is enabled in order to allow the loading application to register the plugin

      and then store its execution report. The execution report gathers information

      about each part of the plugin's code that has been used when

      the plugin was loaded by the launching application.

      The execution report for the plugin will go to the same execution report

      as the one defined for the application loading it.

    */

    int ret = __coveragescanner_register_library(libPrivate->fileName.toLocal8Bit());

    if (qt_debug_component()) {

        if (ret >= 0) {

            qDebug("coverage data for %ls registered",

                   qUtf16Printable(libPrivate->fileName));

        } else {

            qWarning("could not register %ls: error %d; coverage data may be incomplete",

                     qUtf16Printable(libPrivate->fileName),

                     ret);

        }

    }

#else

    Q_UNUSED(libPrivate);

#endif

}

class QLibraryStore

{

public:

    inline ~QLibraryStore();

    static inline QLibraryPrivate *findOrCreate(const QString &fileName, const QString &version, QLibrary::LoadHints loadHints);

    static inline void releaseLibrary(QLibraryPrivate *lib);

    static inline void cleanup();

private:

    static inline QLibraryStore *instance();

    // all members and instance() are protected by qt_library_mutex

    typedef QMap<QString, QLibraryPrivate*> LibraryMap;

    LibraryMap libraryMap;

};

static QBasicMutex qt_library_mutex;

static QLibraryStore *qt_library_data = nullptr;

static bool qt_library_data_once;

QLibraryStore::~QLibraryStore()

{

    qt_library_data = nullptr;

}

inline void QLibraryStore::cleanup()

{

    QLibraryStore *data = qt_library_data;

    if (!data)

        return;

    // find any libraries that are still loaded but have a no one attached to them

    LibraryMap::Iterator it = data->libraryMap.begin();

    for (; it != data->libraryMap.end(); ++it) {

        QLibraryPrivate *lib = it.value();

        if (lib->libraryRefCount.loadRelaxed() == 1) {

            if (lib->libraryUnloadCount.loadRelaxed() > 0) {

                Q_ASSERT(lib->pHnd.loadRelaxed());

                lib->libraryUnloadCount.storeRelaxed(1);

#ifdef __GLIBC__

                // glibc has a bug in unloading from global destructors

                // see https://bugzilla.novell.com/show_bug.cgi?id=622977

                // and http://sourceware.org/bugzilla/show_bug.cgi?id=11941

                lib->unload(QLibraryPrivate::NoUnloadSys);

#elif defined(Q_OS_DARWIN)

                // We cannot fully unload libraries, as we don't know if there are

                // lingering references (in system threads e.g.) to Objective-C classes

                // defined in the library.

                lib->unload(QLibraryPrivate::NoUnloadSys);

#else

                lib->unload();

#endif

            }

            delete lib;

            it.value() = 0;

        }

    }

    if (qt_debug_component()) {

        // dump all objects that remain

        for (QLibraryPrivate *lib : qAsConst(data->libraryMap)) {

            if (lib)

                qDebug() << "On QtCore unload," << lib->fileName << "was leaked, with"

                         << lib->libraryRefCount.loadRelaxed() << "users";

        }

    }

    delete data;

}

static void qlibraryCleanup()

{

    QLibraryStore::cleanup();

}

Q_DESTRUCTOR_FUNCTION(qlibraryCleanup)

// must be called with a locked mutex

QLibraryStore *QLibraryStore::instance()

{

    if (Q_UNLIKELY(!qt_library_data_once && !qt_library_data)) {

        // only create once per process lifetime

        qt_library_data = new QLibraryStore;

        qt_library_data_once = true;

    }

    return qt_library_data;

}

inline QLibraryPrivate *QLibraryStore::findOrCreate(const QString &fileName, const QString &version,

                                                    QLibrary::LoadHints loadHints)

{

    QMutexLocker locker(&qt_library_mutex);

    QLibraryStore *data = instance();

    // check if this library is already loaded

    QLibraryPrivate *lib = nullptr;

    if (Q_LIKELY(data)) {

        lib = data->libraryMap.value(fileName);

        if (lib)

            lib->mergeLoadHints(loadHints);

    }

    if (!lib)

        lib = new QLibraryPrivate(fileName, version, loadHints);

    // track this library

    if (Q_LIKELY(data) && !fileName.isEmpty())

        data->libraryMap.insert(fileName, lib);

    lib->libraryRefCount.ref();

    return lib;

}

inline void QLibraryStore::releaseLibrary(QLibraryPrivate *lib)

{

    QMutexLocker locker(&qt_library_mutex);

    QLibraryStore *data = instance();

    if (lib->libraryRefCount.deref()) {

        // still in use

        return;

    }

    // no one else is using

    Q_ASSERT(lib->libraryUnloadCount.loadRelaxed() == 0);

    if (Q_LIKELY(data) && !lib->fileName.isEmpty()) {

        QLibraryPrivate *that = data->libraryMap.take(lib->fileName);

        Q_ASSERT(lib == that);

        Q_UNUSED(that);

    }

    delete lib;

}

QLibraryPrivate::QLibraryPrivate(const QString &canonicalFileName, const QString &version, QLibrary::LoadHints loadHints)

    : fileName(canonicalFileName), fullVersion(version), pluginState(MightBeAPlugin)

{

    loadHintsInt.storeRelaxed(loadHints);

    if (canonicalFileName.isEmpty())

        errorString = QLibrary::tr("The shared library was not found.");

}

QLibraryPrivate *QLibraryPrivate::findOrCreate(const QString &fileName, const QString &version,

                                               QLibrary::LoadHints loadHints)

{

    return QLibraryStore::findOrCreate(fileName, version, loadHints);

}

QLibraryPrivate::~QLibraryPrivate()

{

}

void QLibraryPrivate::mergeLoadHints(QLibrary::LoadHints lh)

{

    // if the library is already loaded, we can't change the load hints

    if (pHnd.loadRelaxed())

        return;

    loadHintsInt.storeRelaxed(lh);

}

QFunctionPointer QLibraryPrivate::resolve(const char *symbol)

{

    if (!pHnd.loadRelaxed())

        return nullptr;

    return resolve_sys(symbol);

}

void QLibraryPrivate::setLoadHints(QLibrary::LoadHints lh)

{

    // this locks a global mutex

    QMutexLocker lock(&qt_library_mutex);

    mergeLoadHints(lh);

}

QObject *QLibraryPrivate::pluginInstance()

{

    // first, check if the instance is cached and hasn't been deleted

    QObject *obj = (QMutexLocker(&mutex), inst.data());

    if (obj)

        return obj;

    // We need to call the plugin's factory function. Is that cached?

    // skip increasing the reference count (why? -Thiago)

    QtPluginInstanceFunction factory = instanceFactory.loadAcquire();

    if (!factory)

        factory = loadPlugin();

    if (!factory)

        return nullptr;

    obj = factory();

    // cache again

    QMutexLocker locker(&mutex);

    if (inst)

        obj = inst;

    else

        inst = obj;

    return obj;

}

bool QLibraryPrivate::load()

{

    if (pHnd.loadRelaxed()) {

        libraryUnloadCount.ref();

        return true;

    }

    if (fileName.isEmpty())

        return false;

    Q_TRACE(QLibraryPrivate_load_entry, fileName);

    bool ret = load_sys();

    if (qt_debug_component()) {

        if (ret) {

            qDebug() << "loaded library" << fileName;

        } else {

            qDebug() << qUtf8Printable(errorString);

        }

    }

    if (ret) {

        //when loading a library we add a reference to it so that the QLibraryPrivate won't get deleted

        //this allows to unload the library at a later time

        libraryUnloadCount.ref();

        libraryRefCount.ref();

        installCoverageTool(this);

    }

    Q_TRACE(QLibraryPrivate_load_exit, ret);

    return ret;

}

bool QLibraryPrivate::unload(UnloadFlag flag)

{

    if (!pHnd.loadRelaxed())

        return false;

    if (libraryUnloadCount.loadRelaxed() > 0 && !libraryUnloadCount.deref()) { // only unload if ALL QLibrary instance wanted to

        QMutexLocker locker(&mutex);

        delete inst.data();

        if (flag == NoUnloadSys || unload_sys()) {

            if (qt_debug_component())

                qWarning() << "QLibraryPrivate::unload succeeded on" << fileName

                           << (flag == NoUnloadSys ? "(faked)" : "");

            //when the library is unloaded, we release the reference on it so that 'this'

            //can get deleted

            libraryRefCount.deref();

            pHnd.storeRelaxed(nullptr);

            instanceFactory.storeRelaxed(nullptr);

            return true;

        }

    }

    return false;

}

void QLibraryPrivate::release()

{

    QLibraryStore::releaseLibrary(this);

}

QtPluginInstanceFunction QLibraryPrivate::loadPlugin()

{

    if (auto ptr = instanceFactory.loadAcquire()) {

        libraryUnloadCount.ref();

        return ptr;

    }

    if (pluginState == IsNotAPlugin)

        return nullptr;

    if (load()) {

        auto ptr = reinterpret_cast<QtPluginInstanceFunction>(resolve("qt_plugin_instance"));

        instanceFactory.storeRelease(ptr); // two threads may store the same value

        return ptr;

    }

    if (qt_debug_component())

        qWarning() << "QLibraryPrivate::loadPlugin failed on" << fileName << ":" << errorString;

    pluginState = IsNotAPlugin;

    return nullptr;

}

/*!

    Returns \c true if \a fileName has a valid suffix for a loadable

    library; otherwise returns \c false.

    \table

    \header \li Platform \li Valid suffixes

    \row \li Windows     \li \c .dll, \c .DLL

    \row \li Unix/Linux  \li \c .so

    \row \li AIX  \li \c .a

    \row \li HP-UX       \li \c .sl, \c .so (HP-UXi)

    \row \li \macos and iOS   \li \c .dylib, \c .bundle, \c .so

    \endtable

    Trailing versioning numbers on Unix are ignored.

 */

bool QLibrary::isLibrary(const QString &fileName)

{

#if defined(Q_OS_WIN)

    return fileName.endsWith(QLatin1String(".dll"), Qt::CaseInsensitive);

#else // Generic Unix

    QString completeSuffix = QFileInfo(fileName).completeSuffix();

    if (completeSuffix.isEmpty())

        return false;

    const QVector<QStringRef> suffixes = completeSuffix.splitRef(QLatin1Char('.'));

    QStringList validSuffixList;

# if defined(Q_OS_HPUX)

/*

    See "HP-UX Linker and Libraries User's Guide", section "Link-time Differences between PA-RISC and IPF":

    "In PA-RISC (PA-32 and PA-64) shared libraries are suffixed with .sl. In IPF (32-bit and 64-bit),

    the shared libraries are suffixed with .so. For compatibility, the IPF linker also supports the .sl suffix."

 */

    validSuffixList << QLatin1String("sl");

#  if defined __ia64

    validSuffixList << QLatin1String("so");

#  endif

# elif defined(Q_OS_AIX)

    validSuffixList << QLatin1String("a") << QLatin1String("so");

# elif defined(Q_OS_DARWIN)

    // On Apple platforms, dylib look like libmylib.1.0.0.dylib

    if (suffixes.last() == QLatin1String("dylib"))

        return true;

    validSuffixList << QLatin1String("so") << QLatin1String("bundle");

# elif defined(Q_OS_UNIX)

    validSuffixList << QLatin1String("so");

# endif

    // Examples of valid library names:

    //  libfoo.so

    //  libfoo.so.0

    //  libfoo.so.0.3

    //  libfoo-0.3.so

    //  libfoo-0.3.so.0.3.0

    int suffix;

    int suffixPos = -1;

    for (suffix = 0; suffix < validSuffixList.count() && suffixPos == -1; ++suffix)

        suffixPos = suffixes.indexOf(QStringRef(&validSuffixList.at(suffix)));

    bool valid = suffixPos != -1;

    for (int i = suffixPos + 1; i < suffixes.count() && valid; ++i)

        if (i != suffixPos)

            suffixes.at(i).toInt(&valid);

    return valid;

#endif

}

static bool qt_get_metadata(QLibraryPrivate *priv, QString *errMsg)

{

#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)

    auto getMetaData = [](QFunctionPointer fptr) {

        auto f = reinterpret_cast<const char * (*)()>(fptr);

        return qMakePair<const char *, size_t>(f(), INT_MAX);

    };

#else

    auto getMetaData = [](QFunctionPointer fptr) {

        auto f = reinterpret_cast<QPair<const char *, size_t> (*)()>(fptr);

        return f();

    };

#endif

    QFunctionPointer pfn = priv->resolve("qt_plugin_query_metadata");

    if (!pfn)

        return false;

    auto metaData = getMetaData(pfn);

    QJsonDocument doc = qJsonFromRawLibraryMetaData(metaData.first, metaData.second, errMsg);

    if (doc.isNull())

        return false;

    priv->metaData = doc.object();

    return true;

}

bool QLibraryPrivate::isPlugin()

{

    if (pluginState == MightBeAPlugin)

        updatePluginState();

    return pluginState == IsAPlugin;

}

void QLibraryPrivate::updatePluginState()

{

    QMutexLocker locker(&mutex);

    errorString.clear();

    if (pluginState != MightBeAPlugin)

        return;

    bool success = false;

#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)

    if (fileName.endsWith(QLatin1String(".debug"))) {

        // refuse to load a file that ends in .debug

        // these are the debug symbols from the libraries

        // the problem is that they are valid shared library files

        // and dlopen is known to crash while opening them

        // pretend we didn't see the file

        errorString = QLibrary::tr("The shared library was not found.");

        pluginState = IsNotAPlugin;

        return;

    }

#endif

    if (!pHnd.loadRelaxed()) {

        // scan for the plugin metadata without loading

        success = findPatternUnloaded(fileName, this);

    } else {

        // library is already loaded (probably via QLibrary)

        // simply get the target function and call it.

        success = qt_get_metadata(this, &errorString);

    }

    if (!success) {

        if (errorString.isEmpty()){

            if (fileName.isEmpty())

                errorString = QLibrary::tr("The shared library was not found.");

            else

                errorString = QLibrary::tr("The file '%1' is not a valid Qt plugin.").arg(fileName);

        }

        pluginState = IsNotAPlugin;

        return;

    }

    pluginState = IsNotAPlugin; // be pessimistic

    uint qt_version = (uint)metaData.value(QLatin1String("version")).toDouble();

    bool debug = metaData.value(QLatin1String("debug")).toBool();

    if ((qt_version & 0x00ff00) > (QT_VERSION & 0x00ff00) || (qt_version & 0xff0000) != (QT_VERSION & 0xff0000)) {

        if (qt_debug_component()) {

            qWarning("In %s:\n"

                 "  Plugin uses incompatible Qt library (%d.%d.%d) [%s]",

                 QFile::encodeName(fileName).constData(),

                 (qt_version&0xff0000) >> 16, (qt_version&0xff00) >> 8, qt_version&0xff,

                 debug ? "debug" : "release");

        }

        errorString = QLibrary::tr("The plugin '%1' uses incompatible Qt library. (%2.%3.%4) [%5]")

            .arg(fileName,

                 QString::number((qt_version & 0xff0000) >> 16),

                 QString::number((qt_version & 0xff00) >> 8),

                 QString::number(qt_version & 0xff),

                 debug ? QLatin1String("debug") : QLatin1String("release"));

#ifndef QT_NO_DEBUG_PLUGIN_CHECK

    } else if(debug != QLIBRARY_AS_DEBUG) {

        //don't issue a qWarning since we will hopefully find a non-debug? --Sam

        errorString = QLibrary::tr("The plugin '%1' uses incompatible Qt library."

                 " (Cannot mix debug and release libraries.)").arg(fileName);

#endif

    } else {

        pluginState = IsAPlugin;

    }

}

/*!

    Loads the library and returns \c true if the library was loaded

    successfully; otherwise returns \c false. Since resolve() always

    calls this function before resolving any symbols it is not

    necessary to call it explicitly. In some situations you might want

    the library loaded in advance, in which case you would use this

    function.

    \sa unload()

*/

bool QLibrary::load()

{

    if (!d)

        return false;

    if (did_load)

        return d->pHnd.loadRelaxed();

    did_load = true;

    return d->load();

}

/*!

    Unloads the library and returns \c true if the library could be

    unloaded; otherwise returns \c false.

    This happens automatically on application termination, so you

    shouldn't normally need to call this function.

    If other instances of QLibrary are using the same library, the

    call will fail, and unloading will only happen when every instance

    has called unload().

    Note that on Mac OS X 10.3 (Panther), dynamic libraries cannot be unloaded.

    \sa resolve(), load()

*/

bool QLibrary::unload()

{

    if (did_load) {

        did_load = false;

        return d->unload();

    }

    return false;

}

/*!

    Returns \c true if the library is loaded; otherwise returns \c false.

    \sa load()

 */

bool QLibrary::isLoaded() const

{

    return d && d->pHnd.loadRelaxed();

}

/*!

    Constructs a library with the given \a parent.

 */

QLibrary::QLibrary(QObject *parent)

    :QObject(parent), d(nullptr), did_load(false)

{

}

/*!

    Constructs a library object with the given \a parent that will

    load the library specified by \a fileName.

    We recommend omitting the file's suffix in \a fileName, since

    QLibrary will automatically look for the file with the appropriate

    suffix in accordance with the platform, e.g. ".so" on Unix,

    ".dylib" on \macos and iOS, and ".dll" on Windows. (See \l{fileName}.)

 */

QLibrary::QLibrary(const QString& fileName, QObject *parent)

    :QObject(parent), d(nullptr), did_load(false)

{

    setFileName(fileName);

}

/*!

    Constructs a library object with the given \a parent that will

    load the library specified by \a fileName and major version number \a verNum.

    Currently, the version number is ignored on Windows.

    We recommend omitting the file's suffix in \a fileName, since

    QLibrary will automatically look for the file with the appropriate

    suffix in accordance with the platform, e.g. ".so" on Unix,

    ".dylib" on \macos and iOS, and ".dll" on Windows. (See \l{fileName}.)

*/

QLibrary::QLibrary(const QString& fileName, int verNum, QObject *parent)

    :QObject(parent), d(nullptr), did_load(false)

{

    setFileNameAndVersion(fileName, verNum);

}

/*!

    Constructs a library object with the given \a parent that will

    load the library specified by \a fileName and full version number \a version.

    Currently, the version number is ignored on Windows.

    We recommend omitting the file's suffix in \a fileName, since

    QLibrary will automatically look for the file with the appropriate

    suffix in accordance with the platform, e.g. ".so" on Unix,

    ".dylib" on \macos and iOS, and ".dll" on Windows. (See \l{fileName}.)

 */

QLibrary::QLibrary(const QString& fileName, const QString &version, QObject *parent)

    :QObject(parent), d(nullptr), did_load(false)

{

    setFileNameAndVersion(fileName, version);

}

/*!

    Destroys the QLibrary object.

    Unless unload() was called explicitly, the library stays in memory

    until the application terminates.

    \sa isLoaded(), unload()

*/

QLibrary::~QLibrary()

{

    if (d)

        d->release();

}

/*!

    \property QLibrary::fileName

    \brief the file name of the library

    We recommend omitting the file's suffix in the file name, since

    QLibrary will automatically look for the file with the appropriate

    suffix (see isLibrary()).

    When loading the library, QLibrary searches in all system-specific

    library locations (for example, \c LD_LIBRARY_PATH on Unix), unless the

    file name has an absolute path. After loading the library

    successfully, fileName() returns the fully-qualified file name of

    the library, including the full path to the library if one was given

    in the constructor or passed to setFileName().

    For example, after successfully loading the "GL" library on Unix

    platforms, fileName() will return "libGL.so". If the file name was

    originally passed as "/usr/lib/libGL", fileName() will return

    "/usr/lib/libGL.so".