plasma-framework/dataenginemanager.cpp

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/*
* Copyright 2006-2007 Aaron Seigo <aseigo@kde.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details
*
* You should have received a copy of the GNU Library General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "dataenginemanager.h"
#include "scripting/scriptengine.h"
#include <KDebug>
#include <KServiceTypeTrader>
namespace Plasma
{
class NullEngine : public DataEngine
{
public:
NullEngine(QObject* parent = 0)
: DataEngine(parent)
{
setObjectName(i18n("Null Engine"));
setValid(false);
// ref() ourselves to ensure we never get deleted
ref();
}
};
class DataEngineManager::Private
{
public:
Private()
: nullEng(0)
{}
~Private()
{
foreach (Plasma::DataEngine* engine, engines) {
delete engine;
}
engines.clear();
delete nullEng;
}
DataEngine* nullEngine()
{
if (!nullEng) {
nullEng = new NullEngine;
}
return nullEng;
}
DataEngine::Dict engines;
DataEngine* nullEng;
};
class DataEngineManagerSingleton
{
public:
DataEngineManager self;
};
K_GLOBAL_STATIC(DataEngineManagerSingleton, privateDataEngineManagerSelf)
DataEngineManager* DataEngineManager::self()
{
return &privateDataEngineManagerSelf->self;
}
DataEngineManager::DataEngineManager()
: d(new Private())
{
}
DataEngineManager::~DataEngineManager()
{
delete d;
}
Plasma::DataEngine* DataEngineManager::get(const QString& name) const
{
Plasma::DataEngine::Dict::const_iterator it = d->engines.find(name);
if (it != d->engines.end()) {
// ref and return the engine
//Plasma::DataEngine *engine = *it;
return *it;
}
return d->nullEngine();
}
Plasma::DataEngine* DataEngineManager::load(const QString& name)
{
Plasma::DataEngine* engine = 0;
Plasma::DataEngine::Dict::const_iterator it = d->engines.find(name);
if (it != d->engines.end()) {
engine = *it;
engine->ref();
return engine;
}
// load the engine, add it to the engines
QString constraint = QString("[X-Plasma-EngineName] == '%1'").arg(name);
KService::List offers = KServiceTypeTrader::self()->query("Plasma/DataEngine",
constraint);
QString error;
if (offers.isEmpty()) {
kDebug() << "offers are empty for " << name << " with constraint " << constraint;
} else {
QVariantList allArgs;
allArgs << offers.first()->storageId();
QString language = offers.first()->property("X-Plasma-Language").toString();
if (language.isEmpty()) {
engine = offers.first()->createInstance<Plasma::DataEngine>(0, allArgs, &error);
} else {
engine = new DataEngine(0, offers.first());
}
}
if (!engine) {
kDebug() << "Couldn't load engine \"" << name << "\". Error given: " << error;
return d->nullEngine();
}
d->engines[name] = engine;
return engine;
}
void DataEngineManager::unload(const QString& name)
{
Plasma::DataEngine::Dict::iterator it = d->engines.find(name);
if (it != d->engines.end()) {
Plasma::DataEngine* engine = *it;
engine->deref();
if (!engine->isUsed()) {
d->engines.erase(it);
delete engine;
}
}
}
QStringList DataEngineManager::knownEngines()
{
QStringList engines;
KService::List offers = KServiceTypeTrader::self()->query("Plasma/DataEngine");
foreach (KService::Ptr service, offers) {
engines.append(service->property("X-Plasma-EngineName").toString());
}
return engines;
}
} // namespace Plasma
#include "dataenginemanager.moc"