Long live Qt 4.5!

1 files changed, 1130 insertions, 0 deletions

diff --git a/src/corelib/plugin/qlibrary.cpp b/src/corelib/plugin/qlibrary.cpp
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+++ b/src/corelib/plugin/qlibrary.cpp
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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qplatformdefs.h"
+#include "qlibrary.h"
+
+#ifndef QT_NO_LIBRARY
+
+#include "qlibrary_p.h"
+#include <qstringlist.h>
+#include <qfile.h>
+#include <qfileinfo.h>
+#include <qmutex.h>
+#include <qmap.h>
+#include <qsettings.h>
+#include <qdatetime.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>
+
+QT_BEGIN_NAMESPACE
+
+//#define QT_DEBUG_COMPONENT
+
+#ifdef QT_NO_DEBUG
+#  define QLIBRARY_AS_DEBUG false
+#else
+#  define QLIBRARY_AS_DEBUG true
+#endif
+
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+// 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
+
+Q_GLOBAL_STATIC(QMutex, qt_library_mutex)
+
+/*!
+    \class QLibrary
+    \reentrant
+    \brief The QLibrary class loads shared libraries at runtime.
+
+    \mainclass
+    \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
+    cannot be found, QLibrary tries the name with different
+    platform-specific file suffixes, like ".so" on Unix, ".dylib" on
+    the Mac, or ".dll" on Windows. 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.
+
+    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 0 and won't be
+    called.
+
+    \snippet doc/src/snippets/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 doc/src/snippets/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.
+
+    \sa loadHints
+*/
+
+
+#ifndef QT_NO_PLUGIN_CHECK
+struct qt_token_info
+{
+    qt_token_info(const char *f, const ulong fc)
+        : fields(f), field_count(fc), results(fc), lengths(fc)
+    {
+        results.fill(0);
+        lengths.fill(0);
+    }
+
+    const char *fields;
+    const ulong field_count;
+
+    QVector<const char *> results;
+    QVector<ulong> lengths;
+};
+
+/*
+  return values:
+       1 parse ok
+       0 eos
+      -1 parse error
+*/
+static int qt_tokenize(const char *s, ulong s_len, ulong *advance,
+                        qt_token_info &token_info)
+{
+    ulong pos = 0, field = 0, fieldlen = 0;
+    char current;
+    int ret = -1;
+    *advance = 0;
+    for (;;) {
+        current = s[pos];
+
+        // next char
+        ++pos;
+        ++fieldlen;
+        ++*advance;
+
+        if (! current || pos == s_len + 1) {
+            // save result
+            token_info.results[(int)field] = s;
+            token_info.lengths[(int)field] = fieldlen - 1;
+
+            // end of string
+            ret = 0;
+            break;
+        }
+
+        if (current == token_info.fields[field]) {
+            // save result
+            token_info.results[(int)field] = s;
+            token_info.lengths[(int)field] = fieldlen - 1;
+
+            // end of field
+            fieldlen = 0;
+            ++field;
+            if (field == token_info.field_count - 1) {
+                // parse ok
+                ret = 1;
+            }
+            if (field == token_info.field_count) {
+                // done parsing
+                break;
+            }
+
+            // reset string and its length
+            s = s + pos;
+            s_len -= pos;
+            pos = 0;
+        }
+    }
+
+    return ret;
+}
+
+/*
+  returns true if the string s was correctly parsed, false otherwise.
+*/
+static bool qt_parse_pattern(const char *s, uint *version, bool *debug, QByteArray *key)
+{
+    bool ret = true;
+
+    qt_token_info pinfo("=\n", 2);
+    int parse;
+    ulong at = 0, advance, parselen = qstrlen(s);
+    do {
+        parse = qt_tokenize(s + at, parselen, &advance, pinfo);
+        if (parse == -1) {
+            ret = false;
+            break;
+        }
+
+        at += advance;
+        parselen -= advance;
+
+        if (qstrncmp("version", pinfo.results[0], pinfo.lengths[0]) == 0) {
+            // parse version string
+            qt_token_info pinfo2("..-", 3);
+            if (qt_tokenize(pinfo.results[1], pinfo.lengths[1],
+                              &advance, pinfo2) != -1) {
+                QByteArray m(pinfo2.results[0], pinfo2.lengths[0]);
+                QByteArray n(pinfo2.results[1], pinfo2.lengths[1]);
+                QByteArray p(pinfo2.results[2], pinfo2.lengths[2]);
+                *version  = (m.toUInt() << 16) | (n.toUInt() << 8) | p.toUInt();
+            } else {
+                ret = false;
+                break;
+            }
+        } else if (qstrncmp("debug", pinfo.results[0], pinfo.lengths[0]) == 0) {
+            *debug = qstrncmp("true", pinfo.results[1], pinfo.lengths[1]) == 0;
+        } else if (qstrncmp("buildkey", pinfo.results[0],
+                              pinfo.lengths[0]) == 0){
+            // save buildkey
+            *key = QByteArray(pinfo.results[1], pinfo.lengths[1]);
+        }
+    } while (parse == 1 && parselen > 0);
+
+    return ret;
+}
+#endif // QT_NO_PLUGIN_CHECK
+
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC) && !defined(QT_NO_PLUGIN_CHECK)
+
+#if defined(Q_OS_FREEBSD) || defined(Q_OS_LINUX)
+#  define USE_MMAP
+QT_BEGIN_INCLUDE_NAMESPACE
+#  include <sys/types.h>
+#  include <sys/mman.h>
+QT_END_INCLUDE_NAMESPACE
+#endif // Q_OS_FREEBSD || Q_OS_LINUX
+
+static long qt_find_pattern(const char *s, ulong 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 || p_len > s_len) return -1;
+    ulong 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;
+        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 false if version/key information is not present, or if the
+                information could not be read.
+  Returns  true if version/key information is present and successfully read.
+*/
+static bool qt_unix_query(const QString &library, uint *version, bool *debug, QByteArray *key, QLibraryPrivate *lib = 0)
+{
+    QFile file(library);
+    if (!file.open(QIODevice::ReadOnly)) {
+        if (lib)
+            lib->errorString = file.errorString();
+        if (qt_debug_component()) {
+            qWarning("%s: %s", (const char*) QFile::encodeName(library),
+                qPrintable(qt_error_string(errno)));
+        }
+        return false;
+    }
+
+    QByteArray data;
+    char *filedata = 0;
+    ulong fdlen = 0;
+
+#ifdef USE_MMAP
+    char *mapaddr = 0;
+    size_t maplen = file.size();
+    mapaddr = (char *) mmap(mapaddr, maplen, PROT_READ, MAP_PRIVATE, file.handle(), 0);
+    if (mapaddr != MAP_FAILED) {
+        // mmap succeeded
+        filedata = mapaddr;
+        fdlen = maplen;
+    } else {
+        // mmap failed
+        if (qt_debug_component()) {
+            qWarning("mmap: %s", qPrintable(qt_error_string(errno)));
+        }
+        if (lib)
+            lib->errorString = QLibrary::tr("Could not mmap '%1': %2")
+                .arg(library)
+                .arg(qt_error_string());
+#endif // USE_MMAP
+        // try reading the data into memory instead
+        data = file.readAll();
+        filedata = data.data();
+        fdlen = data.size();
+#ifdef USE_MMAP
+    }
+#endif // USE_MMAP
+
+    // verify that the pattern is present in the plugin
+    const char pattern[] = "pattern=QT_PLUGIN_VERIFICATION_DATA";
+    const ulong plen = qstrlen(pattern);
+    long pos = qt_find_pattern(filedata, fdlen, pattern, plen);
+
+    bool ret = false;
+    if (pos >= 0)
+        ret = qt_parse_pattern(filedata + pos, version, debug, key);
+
+    if (!ret && lib)
+        lib->errorString = QLibrary::tr("Plugin verification data mismatch in '%1'").arg(library);
+#ifdef USE_MMAP
+    if (mapaddr != MAP_FAILED && munmap(mapaddr, maplen) != 0) {
+        if (qt_debug_component())
+            qWarning("munmap: %s", qPrintable(qt_error_string(errno)));
+        if (lib)
+            lib->errorString = QLibrary::tr("Could not unmap '%1': %2")
+                .arg(library)
+                .arg( qt_error_string() );
+    }
+#endif // USE_MMAP
+
+    file.close();
+    return ret;
+}
+
+#endif // Q_OS_UNIX && !Q_OS_MAC && !defined(QT_NO_PLUGIN_CHECK)
+
+typedef QMap<QString, QLibraryPrivate*> LibraryMap;
+Q_GLOBAL_STATIC(LibraryMap, libraryMap)
+
+QLibraryPrivate::QLibraryPrivate(const QString &canonicalFileName, const QString &version)
+    :pHnd(0), fileName(canonicalFileName), fullVersion(version), instance(0), qt_version(0),
+     libraryRefCount(1), libraryUnloadCount(0), pluginState(MightBeAPlugin)
+{ libraryMap()->insert(canonicalFileName, this); }
+
+QLibraryPrivate *QLibraryPrivate::findOrCreate(const QString &fileName, const QString &version)
+{
+    QMutexLocker locker(qt_library_mutex());
+    if (QLibraryPrivate *lib = libraryMap()->value(fileName)) {
+        lib->libraryRefCount.ref();
+        return lib;
+    }
+
+    return new QLibraryPrivate(fileName, version);
+}
+
+QLibraryPrivate::~QLibraryPrivate()
+{
+    LibraryMap * const map = libraryMap();
+    if (map) {
+        QLibraryPrivate *that = map->take(fileName);
+        Q_ASSERT(this == that);
+	Q_UNUSED(that);
+    }
+}
+
+void *QLibraryPrivate::resolve(const char *symbol)
+{
+    if (!pHnd)
+        return 0;
+    return resolve_sys(symbol);
+}
+
+
+bool QLibraryPrivate::load()
+{
+    libraryUnloadCount.ref();
+    if (pHnd)
+        return true;
+    if (fileName.isEmpty())
+        return false;
+    return load_sys();
+}
+
+bool QLibraryPrivate::unload()
+{
+    if (!pHnd)
+        return false;
+    if (!libraryUnloadCount.deref()) { // only unload if ALL QLibrary instance wanted to
+        if (instance)
+            delete instance();
+        if  (unload_sys()) {
+            instance = 0;
+            pHnd = 0;
+        }
+    }
+
+    return (pHnd == 0);
+}
+
+void QLibraryPrivate::release()
+{
+    QMutexLocker locker(qt_library_mutex());
+    if (!libraryRefCount.deref())
+        delete this;
+}
+
+bool QLibraryPrivate::loadPlugin()
+{
+    if (instance) {
+        libraryUnloadCount.ref();
+        return true;
+    }
+    if (load()) {
+        instance = (QtPluginInstanceFunction)resolve("qt_plugin_instance");
+        return instance;
+    }
+    return false;
+}
+
+/*!
+    Returns true if \a fileName has a valid suffix for a loadable
+    library; otherwise returns false.
+
+    \table
+    \header \i Platform \i Valid suffixes
+    \row \i Windows     \i \c .dll
+    \row \i Unix/Linux  \i \c .so
+    \row \i AIX  \i \c .a
+    \row \i HP-UX       \i \c .sl, \c .so (HP-UXi)
+    \row \i Mac OS X    \i \c .dylib, \c .bundle, \c .so
+    \endtable
+
+    Trailing versioning numbers on Unix are ignored.
+ */
+bool QLibrary::isLibrary(const QString &fileName)
+{
+#if defined(Q_OS_WIN32) || defined(Q_OS_WINCE)
+    return fileName.endsWith(QLatin1String(".dll"));
+#else
+    QString completeSuffix = QFileInfo(fileName).completeSuffix();
+    if (completeSuffix.isEmpty())
+        return false;
+    QStringList suffixes = completeSuffix.split(QLatin1Char('.'));
+# if defined(Q_OS_DARWIN)
+
+    // On Mac, libs look like libmylib.1.0.0.dylib
+    const QString lastSuffix = suffixes.at(suffixes.count() - 1);
+    const QString firstSuffix = suffixes.at(0);
+
+    bool valid = (lastSuffix == QLatin1String("dylib")
+            || firstSuffix == QLatin1String("so")
+            || firstSuffix == QLatin1String("bundle"));
+
+    return valid;
+# else  // Generic Unix
+    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_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(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
+#endif
+
+}
+
+bool QLibraryPrivate::isPlugin(QSettings *settings)
+{
+    errorString.clear();
+    if (pluginState != MightBeAPlugin)
+        return pluginState == IsAPlugin;
+
+#ifndef QT_NO_PLUGIN_CHECK
+    bool debug = !QLIBRARY_AS_DEBUG;
+    QByteArray key;
+    bool success = false;
+
+    QFileInfo fileinfo(fileName);
+
+#ifndef QT_NO_DATESTRING
+    lastModified  = fileinfo.lastModified().toString(Qt::ISODate);
+#endif
+    QString regkey = QString::fromLatin1("Qt Plugin Cache %1.%2.%3/%4")
+                     .arg((QT_VERSION & 0xff0000) >> 16)
+                     .arg((QT_VERSION & 0xff00) >> 8)
+                     .arg(QLIBRARY_AS_DEBUG ? QLatin1String("debug") : QLatin1String("false"))
+                     .arg(fileName);
+    QStringList reg;
+#ifndef QT_NO_SETTINGS
+    bool madeSettings = false;
+    if (!settings) {
+        settings = new QSettings(QSettings::UserScope, QLatin1String("Trolltech"));
+        madeSettings = true;
+    }
+    reg = settings->value(regkey).toStringList();
+#endif
+    if (reg.count() == 4 && lastModified == reg.at(3)) {
+        qt_version = reg.at(0).toUInt(0, 16);
+        debug = bool(reg.at(1).toInt());
+        key = reg.at(2).toLatin1();
+        success = qt_version != 0;
+    } else {
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+        if (!pHnd) {
+            // use unix shortcut to avoid loading the library
+            success = qt_unix_query(fileName, &qt_version, &debug, &key, this);
+        } else
+#endif
+        {
+            bool temporary_load = false;
+#ifdef Q_OS_WIN
+            HMODULE hTempModule = 0;
+#endif
+            if (!pHnd) {
+#ifdef Q_OS_WIN
+                QT_WA({
+                    hTempModule = ::LoadLibraryExW((wchar_t*)QDir::toNativeSeparators(fileName).utf16(), 0, DONT_RESOLVE_DLL_REFERENCES);
+                } , {
+                    temporary_load = load_sys();
+                });
+#else
+                temporary_load =  load_sys();
+#endif
+            }
+#  ifdef Q_CC_BOR
+            typedef const char * __stdcall (*QtPluginQueryVerificationDataFunction)();
+#  else
+            typedef const char * (*QtPluginQueryVerificationDataFunction)();
+#  endif
+#ifdef Q_OS_WIN
+            QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction = hTempModule
+                ? (QtPluginQueryVerificationDataFunction)
+#ifdef Q_OS_WINCE
+                    ::GetProcAddressW(hTempModule, L"qt_plugin_query_verification_data")
+#else
+                    ::GetProcAddress(hTempModule, "qt_plugin_query_verification_data")
+#endif
+                : (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
+#else
+            QtPluginQueryVerificationDataFunction qtPluginQueryVerificationDataFunction =
+                (QtPluginQueryVerificationDataFunction) resolve("qt_plugin_query_verification_data");
+#endif
+
+            if (!qtPluginQueryVerificationDataFunction
+                || !qt_parse_pattern(qtPluginQueryVerificationDataFunction(), &qt_version, &debug, &key)) {
+                qt_version = 0;
+                key = "unknown";
+                if (temporary_load)
+                    unload_sys();
+            } else {
+                success = true;
+            }
+#ifdef Q_OS_WIN
+            if (hTempModule) {
+                BOOL ok = ::FreeLibrary(hTempModule);
+                if (ok) {
+                    hTempModule = 0;
+                }
+
+            }
+#endif
+        }
+
+        QStringList queried;
+        queried << QString::number(qt_version,16)
+                << QString::number((int)debug)
+                << QLatin1String(key)
+                << lastModified;
+#ifndef QT_NO_SETTINGS
+        settings->setValue(regkey, queried);
+#endif
+    }
+#ifndef QT_NO_SETTINGS
+    if (madeSettings)
+        delete settings;
+#endif
+
+    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);
+        }
+        return false;
+    }
+
+    pluginState = IsNotAPlugin; // be pessimistic
+
+    if ((qt_version > QT_VERSION) || ((QT_VERSION & 0xff0000) > (qt_version & 0xff0000))) {
+        if (qt_debug_component()) {
+            qWarning("In %s:\n"
+                 "  Plugin uses incompatible Qt library (%d.%d.%d) [%s]",
+                 (const char*) QFile::encodeName(fileName),
+                 (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)
+            .arg((qt_version&0xff0000) >> 16)
+            .arg((qt_version&0xff00) >> 8)
+            .arg(qt_version&0xff)
+            .arg(debug ? QLatin1String("debug") : QLatin1String("release"));
+    } else if (key != QT_BUILD_KEY
+#ifdef QT_BUILD_KEY_COMPAT
+               // be sure to load plugins using an older but compatible build key
+               && key != QT_BUILD_KEY_COMPAT
+#endif
+               ) {
+        if (qt_debug_component()) {
+            qWarning("In %s:\n"
+                 "  Plugin uses incompatible Qt library\n"
+                 "  expected build key \"%s\", got \"%s\"",
+                 (const char*) QFile::encodeName(fileName),
+                 QT_BUILD_KEY,
+                 key.isEmpty() ? "<null>" : (const char *) key);
+        }
+        errorString = QLibrary::tr("The plugin '%1' uses incompatible Qt library."
+                 " Expected build key \"%2\", got \"%3\"")
+                 .arg(fileName)
+                 .arg(QLatin1String(QT_BUILD_KEY))
+                 .arg(key.isEmpty() ? QLatin1String("<null>") : QLatin1String((const char *) key));
+#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;
+    }
+
+    return pluginState == IsAPlugin;
+#else
+    Q_UNUSED(settings);
+    return pluginState == MightBeAPlugin;
+#endif
+}
+
+/*!
+    Loads the library and returns true if the library was loaded
+    successfully; otherwise returns 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;
+    did_load = true;
+    return d->load();
+}
+
+/*!
+    Unloads the library and returns true if the library could be
+    unloaded; otherwise returns 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 true if the library is loaded; otherwise returns false.
+
+    \sa load()
+ */
+bool QLibrary::isLoaded() const
+{
+    return d && d->pHnd;
+}
+
+
+/*!
+    Constructs a library with the given \a parent.
+ */
+QLibrary::QLibrary(QObject *parent)
+    :QObject(parent), d(0), 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 Mac OS X, and ".dll" on Windows. (See \l{fileName}.)
+ */
+QLibrary::QLibrary(const QString& fileName, QObject *parent)
+    :QObject(parent), d(0), 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 Mac OS X, and ".dll" on Windows. (See \l{fileName}.)
+ */
+QLibrary::QLibrary(const QString& fileName, int verNum, QObject *parent)
+    :QObject(parent), d(0), 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 Mac OS X, and ".dll" on Windows. (See \l{fileName}.)
+ */
+QLibrary::QLibrary(const QString& fileName, const QString &version, QObject *parent)
+    :QObject(parent), d(0), 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 (e.g. \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".
+*/
+
+void QLibrary::setFileName(const QString &fileName)
+{
+    QLibrary::LoadHints lh;
+    if (d) {
+        lh = d->loadHints;
+        d->release();
+        d = 0;
+        did_load = false;
+    }
+    d = QLibraryPrivate::findOrCreate(fileName);
+    d->loadHints = lh;
+}
+
+QString QLibrary::fileName() const
+{
+    if (d)
+        return d->qualifiedFileName.isEmpty() ? d->fileName : d->qualifiedFileName;
+    return QString();
+}
+
+/*!
+    \fn void QLibrary::setFileNameAndVersion(const QString &fileName, int versionNumber)
+
+    Sets the fileName property and major version number to \a fileName
+    and \a versionNumber respectively.
+    The \a versionNumber is ignored on Windows.
+    \sa setFileName()
+*/
+void QLibrary::setFileNameAndVersion(const QString &fileName, int verNum)
+{
+    QLibrary::LoadHints lh;
+    if (d) {
+        lh = d->loadHints;
+        d->release();
+        d = 0;
+        did_load = false;
+    }
+    d = QLibraryPrivate::findOrCreate(fileName, verNum >= 0 ? QString::number(verNum) : QString());
+    d->loadHints = lh;
+}
+
+/*!
+    \since 4.4
+
+    Sets the fileName property and full version number to \a fileName
+    and \a version respectively.
+    The \a version parameter is ignored on Windows.
+    \sa setFileName()
+*/
+void QLibrary::setFileNameAndVersion(const QString &fileName, const QString &version)
+{
+    QLibrary::LoadHints lh;
+    if (d) {
+        lh = d->loadHints;
+        d->release();
+        d = 0;
+        did_load = false;
+    }
+    d = QLibraryPrivate::findOrCreate(fileName, version);
+    d->loadHints = lh;
+}
+
+/*!
+    Returns the address of the exported symbol \a symbol. The library is
+    loaded if necessary. The function returns 0 if the symbol could
+    not be resolved or if the library could not be loaded.
+
+    Example:
+    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 2
+
+    The symbol must be exported as a C function from the library. This
+    means that the function must be wrapped in an \c{extern "C"} if
+    the library is compiled with a C++ compiler. On Windows you must
+    also explicitly export the function from the DLL using the
+    \c{__declspec(dllexport)} compiler directive, for example:
+
+    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 3
+
+    with \c MY_EXPORT defined as
+
+    \snippet doc/src/snippets/code/src_corelib_plugin_qlibrary.cpp 4
+
+*/
+void *QLibrary::resolve(const char *symbol)
+{
+    if (!load())
+        return 0;
+    return d->resolve(symbol);
+}
+
+/*!
+    \overload
+
+    Loads the library \a fileName and returns the address of the
+    exported symbol \a symbol. Note that \a fileName should not
+    include the platform-specific file suffix; (see \l{fileName}). The
+    library remains loaded until the application exits.
+
+    The function returns 0 if the symbol could not be resolved or if
+    the library could not be loaded.
+
+    \sa resolve()
+*/
+void *QLibrary::resolve(const QString &fileName, const char *symbol)
+{
+    QLibrary library(fileName);
+    return library.resolve(symbol);
+}
+
+/*!
+    \overload
+
+    Loads the library \a fileName with major version number \a verNum and
+    returns the address of the exported symbol \a symbol.
+    Note that \a fileName should not include the platform-specific file suffix;
+    (see \l{fileName}). The library remains loaded until the application exits.
+    \a verNum is ignored on Windows.
+
+    The function returns 0 if the symbol could not be resolved or if
+    the library could not be loaded.
+
+    \sa resolve()
+*/
+void *QLibrary::resolve(const QString &fileName, int verNum, const char *symbol)
+{
+    QLibrary library(fileName, verNum);
+    return library.resolve(symbol);
+}
+
+/*!
+    \overload
+    \since 4.4
+
+    Loads the library \a fileName with full version number \a version and
+    returns the address of the exported symbol \a symbol.
+    Note that \a fileName should not include the platform-specific file suffix;
+    (see \l{fileName}). The library remains loaded until the application exits.
+    \a version is ignored on Windows.
+
+    The function returns 0 if the symbol could not be resolved or if
+    the library could not be loaded.
+
+    \sa resolve()
+*/
+void *QLibrary::resolve(const QString &fileName, const QString &version, const char *symbol)
+{
+    QLibrary library(fileName, version);
+    return library.resolve(symbol);
+}
+
+/*!
+    \fn QString QLibrary::library() const
+
+    Use fileName() instead.
+*/
+
+/*!
+    \fn void QLibrary::setAutoUnload( bool b )
+
+    Use load(), isLoaded(), and unload() as necessary instead.
+*/
+
+/*!
+    \since 4.2
+
+    Returns a text string with the description of the last error that occurred.
+    Currently, errorString will only be set if load(), unload() or resolve() for some reason fails.
+*/
+QString QLibrary::errorString() const
+{
+    return (!d || d->errorString.isEmpty()) ? tr("Unknown error") : d->errorString;
+}
+
+/*!
+    \property QLibrary::loadHints
+    \brief Give the load() function some hints on how it should behave.
+
+    You can give some hints on how the symbols are resolved. Usually,
+    the symbols are not resolved at load time, but resolved lazily,
+    (that is, when resolve() is called). If you set the loadHint to
+    ResolveAllSymbolsHint, then all symbols will be resolved at load time
+    if the platform supports it.
+
+    Setting ExportExternalSymbolsHint will make the external symbols in the
+    library available for resolution in subsequent loaded libraries.
+
+    If LoadArchiveMemberHint is set, the file name
+    is composed of two components: A path which is a reference to an
+    archive file followed by the second component which is the reference to
+    the archive member. For instance, the fileName \c libGL.a(shr_64.o) will refer
+    to the library \c shr_64.o in the archive file named \c libGL.a. This
+    is only supported on the AIX platform.
+
+    The interpretation of the load hints is platform dependent, and if
+    you use it you are probably making some assumptions on which platform
+    you are compiling for, so use them only if you understand the consequences
+    of them.
+
+    By default, none of these flags are set, so libraries will be loaded with
+    lazy symbol resolution, and will not export external symbols for resolution
+    in other dynamically-loaded libraries.
+*/
+void QLibrary::setLoadHints(LoadHints hints)
+{
+    if (!d) {
+        d = QLibraryPrivate::findOrCreate(QString());   // ugly, but we need a d-ptr
+        d->errorString.clear();
+    }
+    d->loadHints = hints;
+}
+
+QLibrary::LoadHints QLibrary::loadHints() const
+{
+    return d ? d->loadHints : (QLibrary::LoadHints)0;
+}
+
+/* Internal, for debugging */
+bool qt_debug_component()
+{
+#if defined(QT_DEBUG_COMPONENT)
+    return true;    //compatibility?
+#else
+    static int debug_env = -1;
+    if (debug_env == -1)
+       debug_env = QT_PREPEND_NAMESPACE(qgetenv)("QT_DEBUG_PLUGINS").toInt();
+
+    return debug_env != 0;
+#endif
+}
+
+QT_END_NAMESPACE
+
+#endif // QT_NO_LIBRARY