Add PathItem.status to report async processing progress

Change-Id: I09ccdf9c542ebca56187284a0d1776b64c98bfe8
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

5 files changed, 78 insertions, 4 deletions

diff --git a/src/quick/items/qquickpathitem.cpp b/src/quick/items/qquickpathitem.cpp
index 964d997806..306e79dc1e 100644
--- a/src/quick/items/qquickpathitem.cpp
+++ b/src/quick/items/qquickpathitem.cpp
@@ -362,6 +362,7 @@ QQuickPathItemPrivate::QQuickPathItemPrivate()
       vpChanged(false),
       rendererType(QQuickPathItem::UnknownRenderer),
       async(false),
+      status(QQuickPathItem::Null),
       renderer(nullptr)
 {
 }
@@ -378,6 +379,15 @@ void QQuickPathItemPrivate::_q_visualPathChanged()
     q->polish();
 }
 
+void QQuickPathItemPrivate::setStatus(QQuickPathItem::Status newStatus)
+{
+    Q_Q(QQuickPathItem);
+    if (status != newStatus) {
+        status = newStatus;
+        emit q->statusChanged();
+    }
+}
+
 QQuickPathItem::QQuickPathItem(QQuickItem *parent)
   : QQuickItem(*(new QQuickPathItemPrivate), parent)
 {
@@ -411,6 +421,12 @@ void QQuickPathItem::setAsynchronous(bool async)
     }
 }
 
+QQuickPathItem::Status QQuickPathItem::status() const
+{
+    Q_D(const QQuickPathItem);
+    return d->status;
+}
+
 static QQuickVisualPath *vpe_at(QQmlListProperty<QQuickVisualPath> *property, int index)
 {
     QQuickPathItemPrivate *d = QQuickPathItemPrivate::get(static_cast<QQuickPathItem *>(property->object));
@@ -492,8 +508,9 @@ void QQuickPathItem::updatePolish()
         emit rendererChanged();
     }
 
-    // endSync() is where expensive calculations may happen, depending on the
-    // backend. Therefore do this only when the item is visible.
+    // endSync() is where expensive calculations may happen (or get kicked off
+    // on worker threads), depending on the backend. Therefore do this only
+    // when the item is visible.
     if (isVisible())
         d->sync();
 
@@ -593,8 +610,20 @@ QSGNode *QQuickPathItemPrivate::createNode()
     return node;
 }
 
+static void q_asyncPathItemReady(void *data)
+{
+    QQuickPathItemPrivate *self = static_cast<QQuickPathItemPrivate *>(data);
+    self->setStatus(QQuickPathItem::Ready);
+}
+
 void QQuickPathItemPrivate::sync()
 {
+    const bool useAsync = async && renderer->flags().testFlag(QQuickAbstractPathRenderer::SupportsAsync);
+    if (useAsync) {
+        setStatus(QQuickPathItem::Processing);
+        renderer->setAsyncCallback(q_asyncPathItemReady, this);
+    }
+
     const int count = vp.count();
     renderer->beginSync(count);
 
@@ -624,7 +653,10 @@ void QQuickPathItemPrivate::sync()
         dirty = 0;
     }
 
-    renderer->endSync(async);
+    renderer->endSync(useAsync);
+
+    if (!useAsync)
+        setStatus(QQuickPathItem::Ready);
 }
 
 // ***** gradient support *****
diff --git a/src/quick/items/qquickpathitem_p.h b/src/quick/items/qquickpathitem_p.h
index 7c962d01fc..1b36348cd2 100644
--- a/src/quick/items/qquickpathitem_p.h
+++ b/src/quick/items/qquickpathitem_p.h
@@ -264,6 +264,7 @@ class Q_QUICK_PRIVATE_EXPORT QQuickPathItem : public QQuickItem
     Q_OBJECT
     Q_PROPERTY(RendererType renderer READ rendererType NOTIFY rendererChanged)
     Q_PROPERTY(bool asynchronous READ asynchronous WRITE setAsynchronous NOTIFY asynchronousChanged)
+    Q_PROPERTY(Status status READ status NOTIFY statusChanged)
     Q_PROPERTY(QQmlListProperty<QQuickVisualPath> visualPaths READ visualPaths)
     Q_CLASSINFO("DefaultProperty", "visualPaths")
 
@@ -276,6 +277,13 @@ public:
     };
     Q_ENUM(RendererType)
 
+    enum Status {
+        Null,
+        Ready,
+        Processing
+    };
+    Q_ENUM(Status)
+
     QQuickPathItem(QQuickItem *parent = nullptr);
     ~QQuickPathItem();
 
@@ -284,6 +292,8 @@ public:
     bool asynchronous() const;
     void setAsynchronous(bool async);
 
+    Status status() const;
+
     QQmlListProperty<QQuickVisualPath> visualPaths();
 
 protected:
@@ -296,6 +306,7 @@ protected:
 Q_SIGNALS:
     void rendererChanged();
     void asynchronousChanged();
+    void statusChanged();
 
 private:
     Q_DISABLE_COPY(QQuickPathItem)
diff --git a/src/quick/items/qquickpathitem_p_p.h b/src/quick/items/qquickpathitem_p_p.h
index faf7b1e451..3c63ec6dc2 100644
--- a/src/quick/items/qquickpathitem_p_p.h
+++ b/src/quick/items/qquickpathitem_p_p.h
@@ -65,6 +65,11 @@ class QSGPlainTexture;
 class QQuickAbstractPathRenderer
 {
 public:
+    enum Flag {
+        SupportsAsync = 0x01
+    };
+    Q_DECLARE_FLAGS(Flags, Flag)
+
     virtual ~QQuickAbstractPathRenderer() { }
 
     // Gui thread
@@ -80,11 +85,15 @@ public:
                                 qreal dashOffset, const QVector<qreal> &dashPattern) = 0;
     virtual void setFillGradient(int index, QQuickPathGradient *gradient) = 0;
     virtual void endSync(bool async) = 0;
+    virtual void setAsyncCallback(void (*)(void *), void *) { }
+    virtual Flags flags() const { return 0; }
 
     // Render thread, with gui blocked
     virtual void updateNode() = 0;
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(QQuickAbstractPathRenderer::Flags)
+
 class QQuickVisualPathPrivate : public QObjectPrivate
 {
     Q_DECLARE_PUBLIC(QQuickVisualPath)
@@ -138,6 +147,7 @@ public:
     void sync();
 
     void _q_visualPathChanged();
+    void setStatus(QQuickPathItem::Status newStatus);
 
     static QQuickPathItemPrivate *get(QQuickPathItem *item) { return item->d_func(); }
 
@@ -145,6 +155,7 @@ public:
     bool vpChanged;
     QQuickPathItem::RendererType rendererType;
     bool async;
+    QQuickPathItem::Status status;
     QQuickAbstractPathRenderer *renderer;
     QVector<QQuickVisualPath *> vp;
 };
diff --git a/src/quick/items/qquickpathitemgenericrenderer.cpp b/src/quick/items/qquickpathitemgenericrenderer.cpp
index 6e4c89742a..59b03e0fd2 100644
--- a/src/quick/items/qquickpathitemgenericrenderer.cpp
+++ b/src/quick/items/qquickpathitemgenericrenderer.cpp
@@ -210,8 +210,16 @@ void QQuickPathItemStrokeRunnable::run()
     emit done(this);
 }
 
+void QQuickPathItemGenericRenderer::setAsyncCallback(void (*callback)(void *), void *data)
+{
+    m_asyncCallback = callback;
+    m_asyncCallbackData = data;
+}
+
 void QQuickPathItemGenericRenderer::endSync(bool async)
 {
+    bool didKickOffAsync = false;
+
     for (int i = 0; i < m_vp.count(); ++i) {
         VisualPathData &d(m_vp[i]);
         if (!d.syncDirty)
@@ -264,6 +272,7 @@ void QQuickPathItemGenericRenderer::endSync(bool async)
                         }
                         r->deleteLater();
                     });
+                    didKickOffAsync = true;
                     threadPool.start(r);
                 } else {
                     triangulateFill(d.path, d.fillColor, &d.fillVertices, &d.fillIndices);
@@ -290,6 +299,7 @@ void QQuickPathItemGenericRenderer::endSync(bool async)
                         }
                         r->deleteLater();
                     });
+                    didKickOffAsync = true;
                     threadPool.start(r);
                 } else {
                     triangulateStroke(d.path, d.pen, d.strokeColor, &d.strokeVertices,
@@ -298,6 +308,9 @@ void QQuickPathItemGenericRenderer::endSync(bool async)
             }
         }
     }
+
+    if (!didKickOffAsync && async && m_asyncCallback)
+        m_asyncCallback(m_asyncCallbackData);
 }
 
 void QQuickPathItemGenericRenderer::maybeUpdateAsyncItem()
@@ -308,6 +321,8 @@ void QQuickPathItemGenericRenderer::maybeUpdateAsyncItem()
     }
     m_accDirty |= DirtyGeom;
     m_item->update();
+    if (m_asyncCallback)
+        m_asyncCallback(m_asyncCallbackData);
 }
 
 // the stroke/fill triangulation functions may be invoked either on the gui
diff --git a/src/quick/items/qquickpathitemgenericrenderer_p.h b/src/quick/items/qquickpathitemgenericrenderer_p.h
index a4ed090004..3193c27cb3 100644
--- a/src/quick/items/qquickpathitemgenericrenderer_p.h
+++ b/src/quick/items/qquickpathitemgenericrenderer_p.h
@@ -77,7 +77,8 @@ public:
     QQuickPathItemGenericRenderer(QQuickItem *item)
         : m_item(item),
           m_rootNode(nullptr),
-          m_accDirty(0)
+          m_accDirty(0),
+          m_asyncCallback(nullptr)
     { }
 
     void beginSync(int totalCount) override;
@@ -92,6 +93,8 @@ public:
                         qreal dashOffset, const QVector<qreal> &dashPattern) override;
     void setFillGradient(int index, QQuickPathGradient *gradient) override;
     void endSync(bool async) override;
+    void setAsyncCallback(void (*)(void *), void *) override;
+    Flags flags() const override { return SupportsAsync; }
 
     void updateNode() override;
 
@@ -140,6 +143,8 @@ private:
     QQuickPathItemGenericNode *m_rootNode;
     QVector<VisualPathData> m_vp;
     int m_accDirty;
+    void (*m_asyncCallback)(void *);
+    void *m_asyncCallbackData;
 };
 
 class QQuickPathItemFillRunnable : public QObject, public QRunnable