From 3d48d7565cf7e2836f2a67b25d595efa4508ebed Mon Sep 17 00:00:00 2001
From: Thomas Hartmann <thomas.hartmann@qt.io>
Date: Tue, 3 Jan 2017 17:28:23 +0100
Subject: [PATCH] QmlDesigner: Delay and compress text changes from editor

This is required to avoid blocking the ui while typing, because
the model is updated.
It will take 400ms without changes to the text until the model
gets updated.

Change-Id: Id428a52c15aeb8f0b802ee0448be8e6777a7402a
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
---
 .../designercore/include/rewriterview.h       |  5 ++-
 .../designercore/model/rewriterview.cpp       | 41 +++++++++++--------
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/src/plugins/qmldesigner/designercore/include/rewriterview.h b/src/plugins/qmldesigner/designercore/include/rewriterview.h
index fe7356366c1..251bbf92b85 100644
--- a/src/plugins/qmldesigner/designercore/include/rewriterview.h
+++ b/src/plugins/qmldesigner/designercore/include/rewriterview.h
@@ -31,6 +31,7 @@
 #include "rewritererror.h"
 
 #include <QScopedPointer>
+#include <QTimer>
 #include <QUrl>
 
 namespace QmlJS {
@@ -170,6 +171,7 @@ protected: // functions
     void setModificationGroupActive(bool active);
     void applyModificationGroupChanges();
     void applyChanges();
+    void amendQmlText();
 
 private: //variables
     TextModifier *m_textModifier = nullptr;
@@ -185,7 +187,8 @@ private: //variables
     QList<RewriterError> m_warnings;
     RewriterTransaction m_removeDefaultPropertyTransaction;
     QString m_rewritingErrorMessage;
-    QString lastCorrectQmlSource;
+    QString m_lastCorrectQmlSource;
+    QTimer m_amendTimer;
 };
 
 } //QmlDesigner
diff --git a/src/plugins/qmldesigner/designercore/model/rewriterview.cpp b/src/plugins/qmldesigner/designercore/model/rewriterview.cpp
index 7e9c9b273d3..8d6ba3ecc84 100644
--- a/src/plugins/qmldesigner/designercore/model/rewriterview.cpp
+++ b/src/plugins/qmldesigner/designercore/model/rewriterview.cpp
@@ -53,6 +53,8 @@ RewriterView::RewriterView(DifferenceHandling differenceHandling, QObject *paren
         m_modelToTextMerger(new Internal::ModelToTextMerger(this)),
         m_textToModelMerger(new Internal::TextToModelMerger(this))
 {
+    m_amendTimer.setSingleShot(true);
+    connect(&m_amendTimer, &QTimer::timeout, this, &RewriterView::amendQmlText);
 }
 
 RewriterView::~RewriterView()
@@ -79,7 +81,7 @@ void RewriterView::modelAttached(Model *model)
     ModelAmender differenceHandler(m_textToModelMerger.data());
     const QString qmlSource = m_textModifier->text();
     if (m_textToModelMerger->load(qmlSource, differenceHandler))
-        lastCorrectQmlSource = qmlSource;
+        m_lastCorrectQmlSource = qmlSource;
 }
 
 void RewriterView::modelAboutToBeDetached(Model * /*model*/)
@@ -411,6 +413,18 @@ void RewriterView::applyChanges()
     }
 }
 
+void RewriterView::amendQmlText()
+{
+    emitCustomNotification(StartRewriterAmend);
+
+    const QString newQmlText = m_textModifier->text();
+
+    ModelAmender differenceHandler(m_textToModelMerger.data());
+    if (m_textToModelMerger->load(newQmlText, differenceHandler))
+        m_lastCorrectQmlSource = newQmlText;
+    emitCustomNotification(EndRewriterAmend);
+}
+
 Internal::ModelNodePositionStorage *RewriterView::positionStorage() const
 {
     return m_positionStorage.data();
@@ -714,22 +728,17 @@ void RewriterView::qmlTextChanged()
 #endif
 
         switch (m_differenceHandling) {
-            case Validate: {
-                ModelValidator differenceHandler(m_textToModelMerger.data());
-                if (m_textToModelMerger->load(newQmlText, differenceHandler))
-                    lastCorrectQmlSource = newQmlText;
-                break;
-            }
+        case Validate: {
+            ModelValidator differenceHandler(m_textToModelMerger.data());
+            if (m_textToModelMerger->load(newQmlText, differenceHandler))
+                m_lastCorrectQmlSource = newQmlText;
+            break;
+        }
 
-            case Amend:
-            default: {
-                emitCustomNotification(StartRewriterAmend);
-                ModelAmender differenceHandler(m_textToModelMerger.data());
-                if (m_textToModelMerger->load(newQmlText, differenceHandler))
-                    lastCorrectQmlSource = newQmlText;
-                emitCustomNotification(EndRewriterAmend);
-                break;
-            }
+        case Amend: {
+            m_amendTimer.start(400);
+            break;
+        }
         }
     }
 }