plasma-framework/dataengine.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 "dataengine.h"
#include <QQueue>
#include <QTimer>
#include <QTimerEvent>
#include <QVariant>
#include <KDebug>
#include "datacontainer.h"
namespace Plasma
{
class DataEngine::Private
{
public:
Private(DataEngine* e)
: engine(e),
ref(0),
updateTimerId(0),
minUpdateFreq(-1),
limit(0),
valid(true)
{
updateTimer = new QTimer(engine);
updateTimer->setSingleShot(true);
updateTimestamp.start();
}
DataContainer* source(const QString& sourceName, bool createWhenMissing = true)
{
DataEngine::SourceDict::const_iterator it = sources.find(sourceName);
if (it != sources.constEnd()) {
DataContainer* s = it.value();
if (limit > 0) {
QQueue<DataContainer*>::iterator it = sourceQueue.begin();
while (it != sourceQueue.end()) {
if (*it == s) {
sourceQueue.erase(it);
break;
}
++it;
}
sourceQueue.enqueue(s);
}
return it.value();
}
if (!createWhenMissing) {
return 0;
}
/*kDebug() << "DataEngine " << engine->objectName()
<< ": could not find DataContainer " << sourceName
<< ", creating" << endl;*/
DataContainer* s = new DataContainer(engine);
s->setObjectName(sourceName);
sources.insert(sourceName, s);
connect(s, SIGNAL(requestUpdate(DataContainer*)), engine, SLOT(internalUpdateSource(DataContainer*)));
if (limit > 0) {
trimQueue();
sourceQueue.enqueue(s);
}
emit engine->newSource(sourceName);
return s;
}
void connectSource(DataContainer* s, QObject* visualization, uint updateInterval, Plasma::IntervalAlignment align)
{
//kDebug() << "connect source called with interval" << updateInterval;
if (updateInterval > 0) {
// never more frequently than allowed, never more than 20 times per second
uint min = qMax(50, minUpdateFreq); // for qMin below
updateInterval = qMax(min, updateInterval);
// align on the 50ms
updateInterval = updateInterval - (updateInterval % 50);
}
s->connectVisualization(visualization, updateInterval, align);
QMetaObject::invokeMethod(visualization, "updated",
Q_ARG(QString, s->objectName()),
Q_ARG(Plasma::DataEngine::Data, s->data()));
}
DataContainer* requestSource(const QString& sourceName)
{
//kDebug() << "requesting source " << sourceName;
DataContainer* s = source(sourceName, false);
if (!s) {
// we didn't find a data source, so give the engine an opportunity to make one
/*kDebug() << "DataEngine " << engine->objectName()
<< ": could not find DataContainer " << sourceName
<< " will create on request" << endl;*/
if (engine->sourceRequested(sourceName)) {
s = source(sourceName, false);
if (s) {
// now we have a source; since it was created on demand, assume
// it should be removed when not used
connect(s, SIGNAL(unused(QString)), engine, SLOT(removeSource(QString)));
}
}
}
return s;
}
void trimQueue()
{
uint queueCount = sourceQueue.count();
while (queueCount >= limit) {
DataContainer* punted = sourceQueue.dequeue();
engine->removeSource(punted->objectName());
}
}
void queueUpdate()
{
if (updateTimer->isActive()) {
return;
}
updateTimer->start(0);
}
DataEngine* engine;
int ref;
int updateTimerId;
int minUpdateFreq;
QTime updateTimestamp;
DataEngine::SourceDict sources;
QQueue<DataContainer*> sourceQueue;
QTimer* updateTimer;
QString icon;
uint limit;
bool valid;
};
DataEngine::DataEngine(QObject* parent)
: QObject(parent),
d(new Private(this))
{
connect(d->updateTimer, SIGNAL(timeout()), this, SLOT(checkForUpdates()));
//FIXME: we should delay this call; to when is the question.
//Update DataEngine::init() api docu when fixed
QTimer::singleShot(0, this, SLOT(startInit()));
}
DataEngine::~DataEngine()
{
//kDebug() << objectName() << ": bye bye birdy! ";
delete d;
}
QStringList DataEngine::sources() const
{
return d->sources.keys();
}
void DataEngine::connectSource(const QString& source, QObject* visualization,
uint updateInterval, Plasma::IntervalAlignment intervalAlignment) const
{
//kDebug() << "connectSource" << source;
DataContainer* s = d->requestSource(source);
if (s) {
d->connectSource(s, visualization, updateInterval, intervalAlignment);
//kDebug() << " ==> source connected";
}
}
void DataEngine::connectAllSources(QObject* visualization, uint updateInterval,
Plasma::IntervalAlignment intervalAlignment) const
{
foreach (DataContainer* s, d->sources) {
d->connectSource(s, visualization, updateInterval, intervalAlignment);
}
}
void DataEngine::disconnectSource(const QString& source, QObject* visualization) const
{
DataContainer* s = d->source(source, false);
if (s) {
s->disconnectVisualization(visualization);
}
}
DataContainer* DataEngine::containerForSource(const QString &source)
{
return d->requestSource(source);
}
DataEngine::Data DataEngine::query(const QString& source) const
{
DataContainer* s = d->requestSource(source);
if (!s) {
return DataEngine::Data();
}
DataEngine::Data data = s->data();
s->checkUsage();
return data;
}
void DataEngine::startInit()
{
init();
}
void DataEngine::internalUpdateSource(DataContainer* source)
{
if (d->minUpdateFreq > 0 &&
source->timeSinceLastUpdate() < d->minUpdateFreq) {
// skip updating this source; it's been too soon
//TODO: should we queue an update in this case? return to this
// once we see the results in real world usage
//kDebug() << "internal update source is delaying" << source->timeSinceLastUpdate() << d->minUpdateFreq;
return;
}
if (updateSource(source->objectName())) {
d->queueUpdate();
}
}
void DataEngine::init()
{
// kDebug() << "DataEngine::init() called ";
// default implementation does nothing. this is for engines that have to
// start things in motion external to themselves before they can work
}
bool DataEngine::sourceRequested(const QString &name)
{
Q_UNUSED(name)
return false;
}
bool DataEngine::updateSource(const QString& source)
{
Q_UNUSED(source);
//kDebug() << "updateSource source" << endl;
return false; //TODO: should this be true to trigger, even needless, updates on every tick?
}
void DataEngine::setData(const QString& source, const QVariant& value)
{
setData(source, source, value);
}
void DataEngine::setData(const QString& source, const QString& key, const QVariant& value)
{
DataContainer* s = d->source(source);
s->setData(key, value);
d->queueUpdate();
}
void DataEngine::setData(const QString &source, const Data &data)
{
DataContainer *s = d->source(source);
Data::const_iterator it = data.constBegin();
while (it != data.constEnd()) {
s->setData(it.key(), it.value());
++it;
}
d->queueUpdate();
}
void DataEngine::clearData(const QString& source)
{
DataContainer* s = d->source(source, false);
if (s) {
s->clearData();
d->queueUpdate();
}
}
void DataEngine::removeData(const QString& source, const QString& key)
{
DataContainer* s = d->source(source, false);
if (s) {
s->setData(key, QVariant());
d->queueUpdate();
}
}
void DataEngine::addSource(DataContainer* source)
{
SourceDict::const_iterator it = d->sources.find(source->objectName());
if (it != d->sources.constEnd()) {
kDebug() << "source named \"" << source->objectName() << "\" already exists.";
return;
}
d->sources.insert(source->objectName(), source);
emit newSource(source->objectName());
}
void DataEngine::setSourceLimit(uint limit)
{
if (d->limit == limit) {
return;
}
d->limit = limit;
if (d->limit > 0) {
d->trimQueue();
} else {
d->sourceQueue.clear();
}
}
void DataEngine::setMinimumUpdateInterval(int minimumMs)
{
d->minUpdateFreq = minimumMs;
}
int DataEngine::minimumUpdateInterval() const
{
return d->minUpdateFreq;
}
void DataEngine::setupdateInterval(uint frequency)
{
killTimer(d->updateTimerId);
d->updateTimerId = 0;
if (frequency > 0) {
d->updateTimerId = startTimer(frequency);
}
}
/*
NOTE: This is not implemented to prevent having to store the value internally.
When there is a good use case for needing access to this value, we can
add another member to the Private class and add this method.
void DataEngine::updateInterval()
{
return d->updateInterval;
}
*/
void DataEngine::removeSource(const QString& source)
{
//kDebug() << "removing source " << source;
SourceDict::iterator it = d->sources.find(source);
if (it != d->sources.end()) {
emit sourceRemoved(it.key());
it.value()->deleteLater();
d->sources.erase(it);
}
}
void DataEngine::clearSources()
{
QMutableHashIterator<QString, Plasma::DataContainer*> it(d->sources);
while (it.hasNext()) {
it.next();
emit sourceRemoved(it.key());
delete it.value();
it.remove();
}
}
void DataEngine::ref()
{
--d->ref;
}
void DataEngine::deref()
{
++d->ref;
}
bool DataEngine::isUsed() const
{
return d->ref != 0;
}
bool DataEngine::isValid() const
{
return d->valid;
}
void DataEngine::setValid(bool valid)
{
d->valid = valid;
}
DataEngine::SourceDict DataEngine::sourceDict() const
{
return d->sources;
}
void DataEngine::timerEvent(QTimerEvent *event)
{
if (event->timerId() != d->updateTimerId) {
return;
}
event->accept();
// if the freq update is less than 0, don't bother
if (d->minUpdateFreq < 0) {
return;
}
// minUpdateFreq
if (d->updateTimestamp.elapsed() < d->minUpdateFreq) {
return;
}
d->updateTimestamp.restart();
QHashIterator<QString, Plasma::DataContainer*> it(d->sources);
while (it.hasNext()) {
it.next();
updateSource(it.key());
}
checkForUpdates();
}
void DataEngine::setIcon(const QString& icon)
{
d->icon = icon;
}
QString DataEngine::icon() const
{
return d->icon;
}
void DataEngine::checkForUpdates()
{
QHashIterator<QString, Plasma::DataContainer*> it(d->sources);
while (it.hasNext()) {
it.next();
it.value()->checkForUpdate();
}
}
}
#include "dataengine.moc"