qskinny/examples/iot-dashboard/src/delegaterecycler.cpp

400 lines
12 KiB
C++

/*
* SPDX-FileCopyrightText: 2011 Marco Martin <mart@kde.org>
* SPDX-FileCopyrightText: 2014 Aleix Pol Gonzalez <aleixpol@blue-systems.com>
*
* SPDX-License-Identifier: LGPL-2.0-or-later
*/
#include "delegaterecycler.h"
#include <QQmlComponent>
#include <QQmlContext>
#include <QQmlEngine>
#include <QDebug>
DelegateRecyclerAttached::DelegateRecyclerAttached(QObject *parent)
: QObject(parent)
{
}
DelegateRecyclerAttached::~DelegateRecyclerAttached()
{}
/*
void setRecycler(DelegateRecycler *recycler)
{
m_recycler = recycler;
}
DelegateRecycler *recycler() const
{
return m_recycler;
}
*/
class DelegateCache
{
public:
DelegateCache();
~DelegateCache();
void ref(QQmlComponent *);
void deref(QQmlComponent *);
void insert(QQmlComponent *, QQuickItem *);
QQuickItem *take(QQmlComponent *);
private:
static const int s_cacheSize = 40;
QHash<QQmlComponent *, int> m_refs;
QHash<QQmlComponent *, QList<QQuickItem *> > m_unusedItems;
};
Q_GLOBAL_STATIC(DelegateCache, s_delegateCache)
DelegateCache::DelegateCache()
{
}
DelegateCache::~DelegateCache()
{
for (auto& item : qAsConst(m_unusedItems)) {
qDeleteAll(item);
}
}
void DelegateCache::ref(QQmlComponent *component)
{
m_refs[component]++;
}
void DelegateCache::deref(QQmlComponent *component)
{
auto itRef = m_refs.find(component);
if (itRef == m_refs.end()) {
return;
}
(*itRef)--;
if (*itRef <= 0) {
m_refs.erase(itRef);
qDeleteAll(m_unusedItems.take(component));
}
}
void DelegateCache::insert(QQmlComponent *component, QQuickItem *item)
{
auto& items = m_unusedItems[component];
if (items.length() >= s_cacheSize) {
item->deleteLater();
return;
}
DelegateRecyclerAttached *attached = qobject_cast<DelegateRecyclerAttached *>(qmlAttachedPropertiesObject<DelegateRecycler>(item, false));
if (attached) {
emit attached->pooled();
}
item->setParentItem(nullptr);
items.append(item);
}
QQuickItem *DelegateCache::take(QQmlComponent *component)
{
auto it = m_unusedItems.find(component);
if (it != m_unusedItems.end() && !it->isEmpty()) {
return it->takeFirst();
}
return nullptr;
}
DelegateRecycler::DelegateRecycler(QQuickItem *parent)
: QQuickItem(parent)
{
setFlags(QQuickItem::ItemIsFocusScope);
}
DelegateRecycler::~DelegateRecycler()
{
if (m_sourceComponent) {
s_delegateCache->insert(m_sourceComponent, m_item);
s_delegateCache->deref(m_sourceComponent);
}
}
void DelegateRecycler::syncIndex()
{
const QVariant newIndex = m_propertiesTracker->property("trackedIndex");
if (!newIndex.isValid()) {
return;
}
QQmlContext *ctx = QQmlEngine::contextForObject(m_item)->parentContext();
ctx->setContextProperty(QStringLiteral("index"), newIndex);
}
void DelegateRecycler::syncModel()
{
const QVariant newModel = m_propertiesTracker->property("trackedModel");
if (!newModel.isValid()) {
return;
}
QQmlContext *ctx = QQmlEngine::contextForObject(m_item)->parentContext();
ctx->setContextProperty(QStringLiteral("model"), newModel);
//try to bind all properties
QObject *modelObj = newModel.value<QObject *>();
if (modelObj) {
const QMetaObject *metaObj = modelObj->metaObject();
for (int i = metaObj->propertyOffset(); i < metaObj->propertyCount(); ++i) {
ctx->setContextProperty(QString::fromUtf8(metaObj->property(i).name()), metaObj->property(i).read(modelObj));
}
}
}
void DelegateRecycler::syncModelProperties()
{
const QVariant model = m_propertiesTracker->property("trackedModel");
if (!model.isValid()) {
return;
}
QQmlContext *ctx = QQmlEngine::contextForObject(m_item)->parentContext();
//try to bind all properties
QObject *modelObj = model.value<QObject *>();
if (modelObj) {
const QMetaObject *metaObj = modelObj->metaObject();
for (int i = metaObj->propertyOffset(); i < metaObj->propertyCount(); ++i) {
ctx->setContextProperty(QString::fromUtf8(metaObj->property(i).name()), metaObj->property(i).read(modelObj));
}
}
}
void DelegateRecycler::syncModelData()
{
const QVariant newModelData = m_propertiesTracker->property("trackedModelData");
if (!newModelData.isValid()) {
return;
}
QQmlContext *ctx = QQmlEngine::contextForObject(m_item)->parentContext();
ctx->setContextProperty(QStringLiteral("modelData"), newModelData);
}
QQmlComponent *DelegateRecycler::sourceComponent() const
{
return m_sourceComponent;
}
void DelegateRecycler::setSourceComponent(QQmlComponent *component)
{
if (component && component->parent() == this) {
qWarning() << "Error: source components cannot be declared inside DelegateRecycler";
return;
}
if (m_sourceComponent == component) {
return;
}
if (!m_propertiesTracker) {
static QHash<QQmlEngine*, QQmlComponent*> propertiesTrackerComponent;
auto engine = qmlEngine(this);
auto it = propertiesTrackerComponent.find(engine);
if (it == propertiesTrackerComponent.end()) {
connect(engine, &QObject::destroyed, engine, [engine] { propertiesTrackerComponent.remove(engine); });
it = propertiesTrackerComponent.insert(engine, new QQmlComponent(engine, engine));
(*it)->setData(QByteArrayLiteral("import QtQuick 2.3\nQtObject{property int trackedIndex: index; property var trackedModel: typeof model != 'undefined' ? model : null; property var trackedModelData: typeof modelData != 'undefined' ? modelData : null}"), QUrl(QStringLiteral("delegaterecycler.cpp")));
}
m_propertiesTracker = (*it)->create(QQmlEngine::contextForObject(this));
connect(m_propertiesTracker, SIGNAL(trackedIndexChanged()), this, SLOT(syncIndex()));
connect(m_propertiesTracker, SIGNAL(trackedModelChanged()), this, SLOT(syncModel()));
connect(m_propertiesTracker, SIGNAL(trackedModelDataChanged()), this, SLOT(syncModelData()));
}
if (m_sourceComponent) {
if (m_item) {
disconnect(m_item.data(), &QQuickItem::implicitWidthChanged, this, &DelegateRecycler::updateHints);
disconnect(m_item.data(), &QQuickItem::implicitHeightChanged, this, &DelegateRecycler::updateHints);
s_delegateCache->insert(component, m_item);
}
s_delegateCache->deref(component);
}
m_sourceComponent = component;
s_delegateCache->ref(component);
m_item = s_delegateCache->take(component);
if (!m_item) {
QQuickItem *candidate = parentItem();
QQmlContext *ctx = nullptr;
while (candidate) {
QQmlContext *parentCtx = QQmlEngine::contextForObject(candidate);
if (parentCtx) {
ctx = new QQmlContext(parentCtx, candidate);
break;
} else {
candidate = candidate->parentItem();
}
}
Q_ASSERT(ctx);
QObject *contextObjectToSet = nullptr;
{
// Find the first parent that has a context object with a valid translationDomain property, i.e. is a KLocalizedContext
QQmlContext *auxCtx = ctx;
while (auxCtx != nullptr) {
QObject *auxCtxObj = auxCtx->contextObject();
if (auxCtxObj && auxCtxObj->property("translationDomain").isValid()) {
contextObjectToSet = auxCtxObj;
break;
}
auxCtx = auxCtx->parentContext();
}
}
if (contextObjectToSet) {
ctx->setContextObject(contextObjectToSet);
}
QObject *modelObj = m_propertiesTracker->property("trackedModel").value<QObject *>();
if (modelObj) {
const QMetaObject *metaObj = modelObj->metaObject();
for (int i = metaObj->propertyOffset(); i < metaObj->propertyCount(); ++i) {
QMetaProperty prop = metaObj->property(i);
ctx->setContextProperty(QString::fromUtf8(prop.name()), prop.read(modelObj));
if (prop.hasNotifySignal()) {
QMetaMethod updateSlot = metaObject()->method(
metaObject()->indexOfSlot("syncModelProperties()"));
connect(modelObj, prop.notifySignal(), this, updateSlot);
}
}
}
ctx->setContextProperty(QStringLiteral("model"), m_propertiesTracker->property("trackedModel"));
ctx->setContextProperty(QStringLiteral("modelData"), m_propertiesTracker->property("trackedModelData"));
ctx->setContextProperty(QStringLiteral("index"), m_propertiesTracker->property("trackedIndex"));
ctx->setContextProperty(QStringLiteral("delegateRecycler"), this);
QObject * obj = component->create(ctx);
m_item = qobject_cast<QQuickItem *>(obj);
if (!m_item) {
obj->deleteLater();
} else {
connect(m_item.data(), &QObject::destroyed, ctx, &QObject::deleteLater);
//if the user binded an explicit width, consider it, otherwise base upon implicit
m_widthFromItem = m_item->width() > 0 && m_item->width() != m_item->implicitWidth();
m_heightFromItem = m_item->height() > 0 && m_item->height() != m_item->implicitHeight();
if (m_widthFromItem && m_heightFromItem) {
connect(m_item.data(), &QQuickItem::heightChanged, this, [this]() {
updateSize(false);
});
}
}
} else {
syncModel();
QQmlContext *ctx = QQmlEngine::contextForObject(m_item)->parentContext();
ctx->setContextProperties({ QQmlContext::PropertyPair{ QStringLiteral("modelData"), m_propertiesTracker->property("trackedModelData") },
QQmlContext::PropertyPair{ QStringLiteral("index"), m_propertiesTracker->property("trackedIndex")},
QQmlContext::PropertyPair{ QStringLiteral("delegateRecycler"), QVariant::fromValue<QObject*>(this) }
});
DelegateRecyclerAttached *attached = qobject_cast<DelegateRecyclerAttached *>(qmlAttachedPropertiesObject<DelegateRecycler>(m_item, false));
if (attached) {
emit attached->reused();
}
}
if (m_item) {
m_item->setParentItem(this);
connect(m_item.data(), &QQuickItem::implicitWidthChanged, this, &DelegateRecycler::updateHints);
connect(m_item.data(), &QQuickItem::implicitHeightChanged, this, &DelegateRecycler::updateHints);
updateSize(true);
}
emit sourceComponentChanged();
}
void DelegateRecycler::resetSourceComponent()
{
s_delegateCache->deref(m_sourceComponent);
m_sourceComponent = nullptr;
}
DelegateRecyclerAttached *DelegateRecycler::qmlAttachedProperties(QObject *object)
{
return new DelegateRecyclerAttached(object);
}
void DelegateRecycler::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry)
{
if (m_item && newGeometry.size() != oldGeometry.size()) {
updateSize(true);
}
QQuickItem::geometryChanged(newGeometry, oldGeometry);
}
void DelegateRecycler::focusInEvent(QFocusEvent *event)
{
QQuickItem::focusInEvent(event);
if (!m_item) {
return;
}
m_item->setFocus(event->reason());
}
void DelegateRecycler::updateHints()
{
updateSize(false);
}
void DelegateRecycler::updateSize(bool parentResized)
{
if (!m_item) {
return;
}
const bool needToUpdateWidth = !m_widthFromItem && parentResized && widthValid();
const bool needToUpdateHeight = !m_heightFromItem && parentResized && heightValid();
if (parentResized) {
m_item->setPosition(QPoint(0,0));
}
if (needToUpdateWidth && needToUpdateHeight) {
m_item->setSize(QSizeF(width(), height()));
} else if (needToUpdateWidth) {
m_item->setWidth(width());
} else if (needToUpdateHeight) {
m_item->setHeight(height());
}
if (m_updatingSize) {
return;
}
m_updatingSize = true;
if (m_heightFromItem) {
setHeight(m_item->height());
}
if (m_widthFromItem) {
setWidth(m_item->width());
}
setImplicitSize(m_item->implicitWidth() >= 0 ? m_item->implicitWidth() : m_item->width(),
m_item->implicitHeight() >= 0 ? m_item->implicitHeight() : m_item->height());
m_updatingSize = false;
}