/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing
**
** This file is part of Qt Creator.
**
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
** following information to ensure the GNU Lesser General Public License
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** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, The Qt Company gives you certain additional
** rights.  These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
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****************************************************************************/

#include "pluginspec.h"

#include "pluginspec_p.h"
#include "iplugin.h"
#include "iplugin_p.h"
#include "pluginmanager.h"

#include <QCoreApplication>
#include <QDebug>
#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QJsonArray>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonValue>
#include <QPluginLoader>
#include <QRegExp>

/*!
    \class ExtensionSystem::PluginDependency
    \brief The PluginDependency class contains the name and required compatible
    version number of a plugin's dependency.

    This reflects the data of a dependency object in the plugin's meta data.
    The name and version are used to resolve the dependency. That is,
    a plugin with the given name and
    plugin \c {compatibility version <= dependency version <= plugin version} is searched for.

    See also ExtensionSystem::IPlugin for more information about plugin dependencies and
    version matching.
*/

/*!
    \variable ExtensionSystem::PluginDependency::name
    String identifier of the plugin.
*/

/*!
    \variable ExtensionSystem::PluginDependency::version
    Version string that a plugin must match to fill this dependency.
*/

/*!
    \variable ExtensionSystem::PluginDependency::type
    Defines whether the dependency is required or optional.
    \sa ExtensionSystem::PluginDependency::Type
*/

/*!
    \enum ExtensionSystem::PluginDependency::Type
    Whether the dependency is required or optional.
    \value Required
           Dependency needs to be there.
    \value Optional
           Dependency is not necessarily needed. You need to make sure that
           the plugin is able to load without this dependency installed, so
           for example you may not link to the dependency's library.
    \value Test
           Dependency needs to be force-loaded for running tests of the plugin.
*/

/*!
    \class ExtensionSystem::PluginSpec
    \brief The PluginSpec class contains the information of the plugin's embedded meta data
    and information about the plugin's current state.

    The plugin spec is also filled with more information as the plugin
    goes through its loading process (see PluginSpec::State).
    If an error occurs, the plugin spec is the place to look for the
    error details.
*/

/*!
    \enum ExtensionSystem::PluginSpec::State
    The State enum indicates the states the plugin goes through while
    it is being loaded.

    The state gives a hint on what went wrong in case of an error.

    \value  Invalid
            Starting point: Even the plugin meta data was not read.
    \value  Read
            The plugin meta data has been successfully read, and its
            information is available via the PluginSpec.
    \value  Resolved
            The dependencies given in the description file have been
            successfully found, and are available via the dependencySpecs() function.
    \value  Loaded
            The plugin's library is loaded and the plugin instance created
            (available through plugin()).
    \value  Initialized
            The plugin instance's IPlugin::initialize() function has been called
            and returned a success value.
    \value  Running
            The plugin's dependencies are successfully initialized and
            extensionsInitialized has been called. The loading process is
            complete.
    \value Stopped
            The plugin has been shut down, i.e. the plugin's IPlugin::aboutToShutdown() function has been called.
    \value Deleted
            The plugin instance has been deleted.
*/

using namespace ExtensionSystem;
using namespace ExtensionSystem::Internal;

/*!
    \internal
*/
uint ExtensionSystem::qHash(const PluginDependency &value)
{
    return qHash(value.name);
}

/*!
    \internal
*/
bool PluginDependency::operator==(const PluginDependency &other) const
{
    return name == other.name && version == other.version && type == other.type;
}

/*!
    \internal
*/
PluginSpec::PluginSpec()
    : d(new PluginSpecPrivate(this))
{
}

/*!
    \internal
*/
PluginSpec::~PluginSpec()
{
    delete d;
    d = 0;
}

/*!
    The plugin name. This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::name() const
{
    return d->name;
}

/*!
    The plugin version. This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::version() const
{
    return d->version;
}

/*!
    The plugin compatibility version. This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::compatVersion() const
{
    return d->compatVersion;
}

/*!
    The plugin vendor. This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::vendor() const
{
    return d->vendor;
}

/*!
    The plugin copyright. This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::copyright() const
{
    return d->copyright;
}

/*!
    The plugin license. This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::license() const
{
    return d->license;
}

/*!
    The plugin description. This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::description() const
{
    return d->description;
}

/*!
    The plugin URL where you can find more information about the plugin.
    This is valid after the PluginSpec::Read state is reached.
*/
QString PluginSpec::url() const
{
    return d->url;
}

/*!
    The category that the plugin belongs to. Categories are groups of plugins which allow for keeping them together in the UI.
    Returns an empty string if the plugin does not belong to a category.
*/
QString PluginSpec::category() const
{
    return d->category;
}

/*!
    A QRegExp matching the platforms this plugin works on. An empty pattern implies all platforms.
    \since 3.0
*/

QRegExp PluginSpec::platformSpecification() const
{
    return d->platformSpecification;
}

bool PluginSpec::isAvailableForHostPlatform() const
{
    return d->platformSpecification.isEmpty() || d->platformSpecification.exactMatch(PluginManager::platformName());
}

bool PluginSpec::isRequired() const
{
    return d->required;
}

/*!
    Returns whether the plugin has its experimental flag set.
*/
bool PluginSpec::isExperimental() const
{
    return d->experimental;
}

/*!
    Returns whether the plugin is disabled by default.
    This might be because the plugin is experimental, or because
    the plugin manager's settings define it as disabled by default.
*/
bool PluginSpec::isDisabledByDefault() const
{
    return d->disabledByDefault;
}

/*!
    Returns whether the plugin should be loaded at startup. True by default.

    The user can change it from the Plugin settings.

    \note This function returns true even if a plugin is disabled because its
    dependencies were not loaded, or an error occurred during loading it.
*/
bool PluginSpec::isEnabledInSettings() const
{
    return d->enabledInSettings;
}

/*!
    Returns whether the plugin is loaded at startup.
    \see PluginSpec::isEnabled
*/
bool PluginSpec::isEffectivelyEnabled() const
{
    if (d->disabledIndirectly
        || (!d->enabledInSettings && !d->forceEnabled)
        || d->forceDisabled) {
        return false;
    }
    return isAvailableForHostPlatform();
}

/*!
    Returns true if loading was not done due to user unselecting this plugin or its dependencies.
*/
bool PluginSpec::isDisabledIndirectly() const
{
    return d->disabledIndirectly;
}

/*!
    Returns whether the plugin is enabled via the -load option on the command line.
*/
bool PluginSpec::isForceEnabled() const
{
    return d->forceEnabled;
}

/*!
    Returns whether the plugin is disabled via the -noload option on the command line.
*/
bool PluginSpec::isForceDisabled() const
{
    return d->forceDisabled;
}

/*!
    The plugin dependencies. This is valid after the PluginSpec::Read state is reached.
*/
QVector<PluginDependency> PluginSpec::dependencies() const
{
    return d->dependencies;
}

/*!
    Returns a list of descriptions of command line arguments the plugin processes.
*/

PluginSpec::PluginArgumentDescriptions PluginSpec::argumentDescriptions() const
{
    return d->argumentDescriptions;
}

/*!
    The absolute path to the directory containing the plugin XML description file
    this PluginSpec corresponds to.
*/
QString PluginSpec::location() const
{
    return d->location;
}

/*!
    The absolute path to the plugin XML description file (including the file name)
    this PluginSpec corresponds to.
*/
QString PluginSpec::filePath() const
{
    return d->filePath;
}

/*!
    Command line arguments specific to the plugin. Set at startup.
*/

QStringList PluginSpec::arguments() const
{
    return d->arguments;
}

/*!
    Sets the command line arguments specific to the plugin to \a arguments.
*/

void PluginSpec::setArguments(const QStringList &arguments)
{
    d->arguments = arguments;
}

/*!
    Adds \a argument to the command line arguments specific to the plugin.
*/

void PluginSpec::addArgument(const QString &argument)
{
    d->arguments.push_back(argument);
}


/*!
    The state in which the plugin currently is.
    See the description of the PluginSpec::State enum for details.
*/
PluginSpec::State PluginSpec::state() const
{
    return d->state;
}

/*!
    Returns whether an error occurred while reading/starting the plugin.
*/
bool PluginSpec::hasError() const
{
    return d->hasError;
}

/*!
    Detailed, possibly multi-line, error description in case of an error.
*/
QString PluginSpec::errorString() const
{
    return d->errorString;
}

/*!
    Returns whether this plugin can be used to fill in a dependency of the given
    \a pluginName and \a version.

        \sa PluginSpec::dependencies()
*/
bool PluginSpec::provides(const QString &pluginName, const QString &version) const
{
    return d->provides(pluginName, version);
}

/*!
    The corresponding IPlugin instance, if the plugin library has already been successfully loaded,
    i.e. the PluginSpec::Loaded state is reached.
*/
IPlugin *PluginSpec::plugin() const
{
    return d->plugin;
}

/*!
    Returns the list of dependencies, already resolved to existing plugin specs.
    Valid if PluginSpec::Resolved state is reached.

    \sa PluginSpec::dependencies()
*/
QHash<PluginDependency, PluginSpec *> PluginSpec::dependencySpecs() const
{
    return d->dependencySpecs;
}

//==========PluginSpecPrivate==================

namespace {
    const char PLUGIN_METADATA[] = "MetaData";
    const char PLUGIN_NAME[] = "Name";
    const char PLUGIN_VERSION[] = "Version";
    const char PLUGIN_COMPATVERSION[] = "CompatVersion";
    const char PLUGIN_REQUIRED[] = "Required";
    const char PLUGIN_EXPERIMENTAL[] = "Experimental";
    const char PLUGIN_DISABLED_BY_DEFAULT[] = "DisabledByDefault";
    const char VENDOR[] = "Vendor";
    const char COPYRIGHT[] = "Copyright";
    const char LICENSE[] = "License";
    const char DESCRIPTION[] = "Description";
    const char URL[] = "Url";
    const char CATEGORY[] = "Category";
    const char PLATFORM[] = "Platform";
    const char DEPENDENCIES[] = "Dependencies";
    const char DEPENDENCY_NAME[] = "Name";
    const char DEPENDENCY_VERSION[] = "Version";
    const char DEPENDENCY_TYPE[] = "Type";
    const char DEPENDENCY_TYPE_SOFT[] = "optional";
    const char DEPENDENCY_TYPE_HARD[] = "required";
    const char DEPENDENCY_TYPE_TEST[] = "test";
    const char ARGUMENTS[] = "Arguments";
    const char ARGUMENT_NAME[] = "Name";
    const char ARGUMENT_PARAMETER[] = "Parameter";
    const char ARGUMENT_DESCRIPTION[] = "Description";
}
/*!
    \internal
*/
PluginSpecPrivate::PluginSpecPrivate(PluginSpec *spec)
    : required(false),
      experimental(false),
      disabledByDefault(false),
      enabledInSettings(true),
      disabledIndirectly(false),
      forceEnabled(false),
      forceDisabled(false),
      plugin(0),
      state(PluginSpec::Invalid),
      hasError(false),
      q(spec)
{
}

/*!
    \internal
    Returns false if the file does not represent a Qt Creator plugin.
*/
bool PluginSpecPrivate::read(const QString &fileName)
{
    qCDebug(pluginLog) << "\nReading meta data of" << fileName;
    name
        = version
        = compatVersion
        = vendor
        = copyright
        = license
        = description
        = url
        = category
        = location
        = QString();
    state = PluginSpec::Invalid;
    hasError = false;
    errorString.clear();
    dependencies.clear();
    QFileInfo fileInfo(fileName);
    location = fileInfo.absolutePath();
    filePath = fileInfo.absoluteFilePath();
    loader.setFileName(filePath);
    if (loader.fileName().isEmpty()) {
        qCDebug(pluginLog) << "Cannot open file";
        return false;
    }

    if (!readMetaData(loader.metaData()))
        return false;

    state = PluginSpec::Read;
    return true;
}

void PluginSpec::setEnabled(bool value)
{
    d->enabledInSettings = value;
}

void PluginSpec::setDisabledByDefault(bool value)
{
    d->disabledByDefault = value;
}

void PluginSpec::setForceEnabled(bool value)
{
    d->forceEnabled = value;
    if (value)
        d->forceDisabled = false;
}

void PluginSpec::setForceDisabled(bool value)
{
    if (value)
        d->forceEnabled = false;
    d->forceDisabled = value;
}

/*!
    \internal
*/
bool PluginSpecPrivate::reportError(const QString &err)
{
    errorString = err;
    hasError = true;
    return true;
}

static inline QString msgValueMissing(const char *key)
{
    return QCoreApplication::translate("PluginSpec", "\"%1\" is missing").arg(QLatin1String(key));
}

static inline QString msgValueIsNotAString(const char *key)
{
    return QCoreApplication::translate("PluginSpec", "Value for key \"%1\" is not a string")
            .arg(QLatin1String(key));
}

static inline QString msgValueIsNotABool(const char *key)
{
    return QCoreApplication::translate("PluginSpec", "Value for key \"%1\" is not a bool")
            .arg(QLatin1String(key));
}

static inline QString msgValueIsNotAObjectArray(const char *key)
{
    return QCoreApplication::translate("PluginSpec", "Value for key \"%1\" is not an array of objects")
            .arg(QLatin1String(key));
}

static inline QString msgValueIsNotAMultilineString(const char *key)
{
    return QCoreApplication::translate("PluginSpec", "Value for key \"%1\" is not a string and not an array of strings")
            .arg(QLatin1String(key));
}

static inline QString msgInvalidFormat(const char *key, const QString &content)
{
    return QCoreApplication::translate("PluginSpec", "Value \"%2\" for key \"%1\" has invalid format")
            .arg(QLatin1String(key), content);
}

static inline bool readMultiLineString(const QJsonValue &value, QString *out)
{
    if (!out) {
        qCWarning(pluginLog) << Q_FUNC_INFO << "missing output parameter";
        return false;
    }
    if (value.isString()) {
        *out = value.toString();
    } else if (value.isArray()) {
        QJsonArray array = value.toArray();
        QStringList lines;
        foreach (const QJsonValue &v, array) {
            if (!v.isString())
                return false;
            lines.append(v.toString());
        }
        *out = lines.join(QLatin1Char('\n'));
    } else {
        return false;
    }
    return true;
}

/*!
    \internal
*/
bool PluginSpecPrivate::readMetaData(const QJsonObject &metaData)
{
    qCDebug(pluginLog) << "MetaData:" << QJsonDocument(metaData).toJson();
    QJsonValue value;
    value = metaData.value(QLatin1String("IID"));
    if (!value.isString()) {
        qCDebug(pluginLog) << "Not a plugin (no string IID found)";
        return false;
    }
    if (value.toString() != PluginManager::pluginIID()) {
        qCDebug(pluginLog) << "Plugin ignored (IID does not match)";
        return false;
    }

    value = metaData.value(QLatin1String(PLUGIN_METADATA));
    if (!value.isObject())
        return reportError(tr("Plugin meta data not found"));
    QJsonObject pluginInfo = value.toObject();

    value = pluginInfo.value(QLatin1String(PLUGIN_NAME));
    if (value.isUndefined())
        return reportError(msgValueMissing(PLUGIN_NAME));
    if (!value.isString())
        return reportError(msgValueIsNotAString(PLUGIN_NAME));
    name = value.toString();

    value = pluginInfo.value(QLatin1String(PLUGIN_VERSION));
    if (value.isUndefined())
        return reportError(msgValueMissing(PLUGIN_VERSION));
    if (!value.isString())
        return reportError(msgValueIsNotAString(PLUGIN_VERSION));
    version = value.toString();
    if (!isValidVersion(version))
        return reportError(msgInvalidFormat(PLUGIN_VERSION, version));

    value = pluginInfo.value(QLatin1String(PLUGIN_COMPATVERSION));
    if (!value.isUndefined() && !value.isString())
        return reportError(msgValueIsNotAString(PLUGIN_COMPATVERSION));
    compatVersion = value.toString(version);
    if (!value.isUndefined() && !isValidVersion(compatVersion))
        return reportError(msgInvalidFormat(PLUGIN_COMPATVERSION, compatVersion));

    value = pluginInfo.value(QLatin1String(PLUGIN_REQUIRED));
    if (!value.isUndefined() && !value.isBool())
        return reportError(msgValueIsNotABool(PLUGIN_REQUIRED));
    required = value.toBool(false);
    qCDebug(pluginLog) << "required =" << required;

    value = pluginInfo.value(QLatin1String(PLUGIN_EXPERIMENTAL));
    if (!value.isUndefined() && !value.isBool())
        return reportError(msgValueIsNotABool(PLUGIN_EXPERIMENTAL));
    experimental = value.toBool(false);
    qCDebug(pluginLog) << "experimental =" << experimental;

    value = pluginInfo.value(QLatin1String(PLUGIN_DISABLED_BY_DEFAULT));
    if (!value.isUndefined() && !value.isBool())
        return reportError(msgValueIsNotABool(PLUGIN_DISABLED_BY_DEFAULT));
    disabledByDefault = value.toBool(false);
    qCDebug(pluginLog) << "disabledByDefault =" << disabledByDefault;

    if (experimental)
        disabledByDefault = true;
    enabledInSettings = !disabledByDefault;

    value = pluginInfo.value(QLatin1String(VENDOR));
    if (!value.isUndefined() && !value.isString())
        return reportError(msgValueIsNotAString(VENDOR));
    vendor = value.toString();

    value = pluginInfo.value(QLatin1String(COPYRIGHT));
    if (!value.isUndefined() && !value.isString())
        return reportError(msgValueIsNotAString(COPYRIGHT));
    copyright = value.toString();

    value = pluginInfo.value(QLatin1String(DESCRIPTION));
    if (!value.isUndefined() && !readMultiLineString(value, &description))
        return reportError(msgValueIsNotAString(DESCRIPTION));

    value = pluginInfo.value(QLatin1String(URL));
    if (!value.isUndefined() && !value.isString())
        return reportError(msgValueIsNotAString(URL));
    url = value.toString();

    value = pluginInfo.value(QLatin1String(CATEGORY));
    if (!value.isUndefined() && !value.isString())
        return reportError(msgValueIsNotAString(CATEGORY));
    category = value.toString();

    value = pluginInfo.value(QLatin1String(LICENSE));
    if (!value.isUndefined() && !readMultiLineString(value, &license))
        return reportError(msgValueIsNotAMultilineString(LICENSE));

    value = pluginInfo.value(QLatin1String(PLATFORM));
    if (!value.isUndefined() && !value.isString())
        return reportError(msgValueIsNotAString(PLATFORM));
    const QString platformSpec = value.toString().trimmed();
    if (!platformSpec.isEmpty()) {
        platformSpecification.setPattern(platformSpec);
        if (!platformSpecification.isValid())
            return reportError(tr("Invalid platform specification \"%1\": %2")
                               .arg(platformSpec, platformSpecification.errorString()));
    }

    value = pluginInfo.value(QLatin1String(DEPENDENCIES));
    if (!value.isUndefined() && !value.isArray())
        return reportError(msgValueIsNotAObjectArray(DEPENDENCIES));
    if (!value.isUndefined()) {
        QJsonArray array = value.toArray();
        foreach (const QJsonValue &v, array) {
            if (!v.isObject())
                return reportError(msgValueIsNotAObjectArray(DEPENDENCIES));
            QJsonObject dependencyObject = v.toObject();
            PluginDependency dep;
            value = dependencyObject.value(QLatin1String(DEPENDENCY_NAME));
            if (value.isUndefined())
                return reportError(tr("Dependency: %1").arg(msgValueMissing(DEPENDENCY_NAME)));
            if (!value.isString())
                return reportError(tr("Dependency: %1").arg(msgValueIsNotAString(DEPENDENCY_NAME)));
            dep.name = value.toString();
            value = dependencyObject.value(QLatin1String(DEPENDENCY_VERSION));
            if (!value.isUndefined() && !value.isString())
                return reportError(tr("Dependency: %1").arg(msgValueIsNotAString(DEPENDENCY_VERSION)));
            dep.version = value.toString();
            if (!isValidVersion(dep.version))
                return reportError(tr("Dependency: %1").arg(msgInvalidFormat(DEPENDENCY_VERSION,
                                                                             dep.version)));
            dep.type = PluginDependency::Required;
            value = dependencyObject.value(QLatin1String(DEPENDENCY_TYPE));
            if (!value.isUndefined() && !value.isString())
                return reportError(tr("Dependency: %1").arg(msgValueIsNotAString(DEPENDENCY_TYPE)));
            if (!value.isUndefined()) {
                const QString typeValue = value.toString();
                if (typeValue.toLower() == QLatin1String(DEPENDENCY_TYPE_HARD)) {
                    dep.type = PluginDependency::Required;
                } else if (typeValue.toLower() == QLatin1String(DEPENDENCY_TYPE_SOFT)) {
                    dep.type = PluginDependency::Optional;
                } else if (typeValue.toLower() == QLatin1String(DEPENDENCY_TYPE_TEST)) {
                    dep.type = PluginDependency::Test;
                } else {
                    return reportError(tr("Dependency: \"%1\" must be \"%2\" or \"%3\" (is \"%4\")")
                                       .arg(QLatin1String(DEPENDENCY_TYPE),
                                            QLatin1String(DEPENDENCY_TYPE_HARD),
                                            QLatin1String(DEPENDENCY_TYPE_SOFT),
                                            typeValue));
                }
            }
            dependencies.append(dep);
        }
    }

    value = pluginInfo.value(QLatin1String(ARGUMENTS));
    if (!value.isUndefined() && !value.isArray())
        return reportError(msgValueIsNotAObjectArray(ARGUMENTS));
    if (!value.isUndefined()) {
        QJsonArray array = value.toArray();
        foreach (const QJsonValue &v, array) {
            if (!v.isObject())
                return reportError(msgValueIsNotAObjectArray(ARGUMENTS));
            QJsonObject argumentObject = v.toObject();
            PluginArgumentDescription arg;
            value = argumentObject.value(QLatin1String(ARGUMENT_NAME));
            if (value.isUndefined())
                return reportError(tr("Argument: %1").arg(msgValueMissing(ARGUMENT_NAME)));
            if (!value.isString())
                return reportError(tr("Argument: %1").arg(msgValueIsNotAString(ARGUMENT_NAME)));
            arg.name = value.toString();
            if (arg.name.isEmpty())
                return reportError(tr("Argument: \"%1\" is empty").arg(QLatin1String(ARGUMENT_NAME)));
            value = argumentObject.value(QLatin1String(ARGUMENT_DESCRIPTION));
            if (!value.isUndefined() && !value.isString())
                return reportError(tr("Argument: %1").arg(msgValueIsNotAString(ARGUMENT_DESCRIPTION)));
            arg.description = value.toString();
            value = argumentObject.value(QLatin1String(ARGUMENT_PARAMETER));
            if (!value.isUndefined() && !value.isString())
                return reportError(tr("Argument: %1").arg(msgValueIsNotAString(ARGUMENT_PARAMETER)));
            arg.parameter = value.toString();
            argumentDescriptions.append(arg);
            qCDebug(pluginLog) << "Argument:" << arg.name << "Parameter:" << arg.parameter
                               << "Description:" << arg.description;
        }
    }

    return true;
}

/*!
    \internal
*/
bool PluginSpecPrivate::provides(const QString &pluginName, const QString &pluginVersion) const
{
    if (QString::compare(pluginName, name, Qt::CaseInsensitive) != 0)
        return false;
    return (versionCompare(version, pluginVersion) >= 0) && (versionCompare(compatVersion, pluginVersion) <= 0);
}

/*!
    \internal
*/
QRegExp &PluginSpecPrivate::versionRegExp()
{
    static QRegExp reg(QLatin1String("([0-9]+)(?:[.]([0-9]+))?(?:[.]([0-9]+))?(?:_([0-9]+))?"));
    return reg;
}
/*!
    \internal
*/
bool PluginSpecPrivate::isValidVersion(const QString &version)
{
    return versionRegExp().exactMatch(version);
}

/*!
    \internal
*/
int PluginSpecPrivate::versionCompare(const QString &version1, const QString &version2)
{
    QRegExp reg1 = versionRegExp();
    QRegExp reg2 = versionRegExp();
    if (!reg1.exactMatch(version1))
        return 0;
    if (!reg2.exactMatch(version2))
        return 0;
    int number1;
    int number2;
    for (int i = 0; i < 4; ++i) {
        number1 = reg1.cap(i+1).toInt();
        number2 = reg2.cap(i+1).toInt();
        if (number1 < number2)
            return -1;
        if (number1 > number2)
            return 1;
    }
    return 0;
}

/*!
    \internal
*/
bool PluginSpecPrivate::resolveDependencies(const QList<PluginSpec *> &specs)
{
    if (hasError)
        return false;
    if (state == PluginSpec::Resolved)
        state = PluginSpec::Read; // Go back, so we just re-resolve the dependencies.
    if (state != PluginSpec::Read) {
        errorString = QCoreApplication::translate("PluginSpec", "Resolving dependencies failed because state != Read");
        hasError = true;
        return false;
    }
    QHash<PluginDependency, PluginSpec *> resolvedDependencies;
    foreach (const PluginDependency &dependency, dependencies) {
        PluginSpec *found = 0;

        foreach (PluginSpec *spec, specs) {
            if (spec->provides(dependency.name, dependency.version)) {
                found = spec;
                break;
            }
        }
        if (!found) {
            if (dependency.type == PluginDependency::Required) {
                hasError = true;
                if (!errorString.isEmpty())
                    errorString.append(QLatin1Char('\n'));
                errorString.append(QCoreApplication::translate("PluginSpec", "Could not resolve dependency '%1(%2)'")
                    .arg(dependency.name).arg(dependency.version));
            }
            continue;
        }
        resolvedDependencies.insert(dependency, found);
    }
    if (hasError)
        return false;

    dependencySpecs = resolvedDependencies;

    state = PluginSpec::Resolved;

    return true;
}

void PluginSpecPrivate::disableIndirectlyIfDependencyDisabled()
{
    if (!enabledInSettings)
        return;

    if (disabledIndirectly)
        return;

    QHashIterator<PluginDependency, PluginSpec *> it(dependencySpecs);
    while (it.hasNext()) {
        it.next();
        if (it.key().type != PluginDependency::Required)
            continue;
        PluginSpec *dependencySpec = it.value();
        if (!dependencySpec->isEffectivelyEnabled()) {
            disabledIndirectly = true;
            break;
        }
    }
}

/*!
    \internal
*/
bool PluginSpecPrivate::loadLibrary()
{
    if (hasError)
        return false;
    if (state != PluginSpec::Resolved) {
        if (state == PluginSpec::Loaded)
            return true;
        errorString = QCoreApplication::translate("PluginSpec", "Loading the library failed because state != Resolved");
        hasError = true;
        return false;
    }
    if (!loader.load()) {
        hasError = true;
        errorString = QDir::toNativeSeparators(filePath)
            + QString::fromLatin1(": ") + loader.errorString();
        return false;
    }
    IPlugin *pluginObject = qobject_cast<IPlugin*>(loader.instance());
    if (!pluginObject) {
        hasError = true;
        errorString = QCoreApplication::translate("PluginSpec", "Plugin is not valid (does not derive from IPlugin)");
        loader.unload();
        return false;
    }
    state = PluginSpec::Loaded;
    plugin = pluginObject;
    plugin->d->pluginSpec = q;
    return true;
}

/*!
    \internal
*/
bool PluginSpecPrivate::initializePlugin()
{
    if (hasError)
        return false;
    if (state != PluginSpec::Loaded) {
        if (state == PluginSpec::Initialized)
            return true;
        errorString = QCoreApplication::translate("PluginSpec", "Initializing the plugin failed because state != Loaded");
        hasError = true;
        return false;
    }
    if (!plugin) {
        errorString = QCoreApplication::translate("PluginSpec", "Internal error: have no plugin instance to initialize");
        hasError = true;
        return false;
    }
    QString err;
    if (!plugin->initialize(arguments, &err)) {
        errorString = QCoreApplication::translate("PluginSpec", "Plugin initialization failed: %1").arg(err);
        hasError = true;
        return false;
    }
    state = PluginSpec::Initialized;
    return true;
}

/*!
    \internal
*/
bool PluginSpecPrivate::initializeExtensions()
{
    if (hasError)
        return false;
    if (state != PluginSpec::Initialized) {
        if (state == PluginSpec::Running)
            return true;
        errorString = QCoreApplication::translate("PluginSpec", "Cannot perform extensionsInitialized because state != Initialized");
        hasError = true;
        return false;
    }
    if (!plugin) {
        errorString = QCoreApplication::translate("PluginSpec", "Internal error: have no plugin instance to perform extensionsInitialized");
        hasError = true;
        return false;
    }
    plugin->extensionsInitialized();
    state = PluginSpec::Running;
    return true;
}

/*!
    \internal
*/
bool PluginSpecPrivate::delayedInitialize()
{
    if (hasError)
        return false;
    if (state != PluginSpec::Running)
        return false;
    if (!plugin) {
        errorString = QCoreApplication::translate("PluginSpec", "Internal error: have no plugin instance to perform delayedInitialize");
        hasError = true;
        return false;
    }
    return plugin->delayedInitialize();
}

/*!
    \internal
*/
IPlugin::ShutdownFlag PluginSpecPrivate::stop()
{
    if (!plugin)
        return IPlugin::SynchronousShutdown;
    state = PluginSpec::Stopped;
    return plugin->aboutToShutdown();
}

/*!
    \internal
*/
void PluginSpecPrivate::kill()
{
    if (!plugin)
        return;
    delete plugin;
    plugin = 0;
    state = PluginSpec::Deleted;
}
