From abd3808574f791af606cdbdf6477b3f6cdebcd95 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Sun, 29 Apr 2012 19:30:12 +0200
Subject: [PATCH] Read KWin Script from file moved into thread

The I/O intensive reading of the complete KWin Script
file into a QByteArray is moved into a thread.

Evaluating and setting up the script engine is still
performed in the main thread.

REVIEW: 104782
---
 scripting/scripting.cpp | 61 +++++++++++++++++++++++++++++++----------
 scripting/scripting.h   | 10 +++++++
 2 files changed, 56 insertions(+), 15 deletions(-)

diff --git a/scripting/scripting.cpp b/scripting/scripting.cpp
index 5aad56327a..3405a410bf 100644
--- a/scripting/scripting.cpp
+++ b/scripting/scripting.cpp
@@ -156,6 +156,7 @@ void KWin::AbstractScript::installScriptFunctions(QScriptEngine* engine)
 KWin::Script::Script(int id, QString scriptName, QString pluginName, QObject* parent)
     : AbstractScript(id, scriptName, pluginName, parent)
     , m_engine(new QScriptEngine(this))
+    , m_starting(false)
 {
     QDBusConnection::sessionBus().registerObject('/' + QString::number(scriptId()), this, QDBusConnection::ExportScriptableContents | QDBusConnection::ExportScriptableInvokables);
 }
@@ -167,26 +168,56 @@ KWin::Script::~Script()
 
 void KWin::Script::run()
 {
-    if (running()) {
+    if (running() || m_starting) {
         return;
     }
-    if (scriptFile().open(QIODevice::ReadOnly)) {
-        QScriptValue optionsValue = m_engine->newQObject(options, QScriptEngine::QtOwnership,
-                                QScriptEngine::ExcludeSuperClassContents | QScriptEngine::ExcludeDeleteLater);
-        m_engine->globalObject().setProperty("options", optionsValue, QScriptValue::Undeletable);
-        m_engine->globalObject().setProperty("QTimer", constructTimerClass(m_engine));
-        QObject::connect(m_engine, SIGNAL(signalHandlerException(QScriptValue)), this, SLOT(sigException(QScriptValue)));
-        KWin::MetaScripting::supplyConfig(m_engine);
-        installScriptFunctions(m_engine);
+    m_starting = true;
+    QFutureWatcher<QByteArray> *watcher = new QFutureWatcher<QByteArray>(this);
+    connect(watcher, SIGNAL(finished()), SLOT(slotScriptLoadedFromFile()));
+    watcher->setFuture(QtConcurrent::run(this, &KWin::Script::loadScriptFromFile));
+}
 
-        QScriptValue ret = m_engine->evaluate(scriptFile().readAll());
-
-        if (ret.isError()) {
-            sigException(ret);
-            deleteLater();
-        }
+QByteArray KWin::Script::loadScriptFromFile()
+{
+    if (!scriptFile().open(QIODevice::ReadOnly)) {
+        return QByteArray();
     }
+    QByteArray result(scriptFile().readAll());
+    scriptFile().close();
+    return result;
+}
+
+void KWin::Script::slotScriptLoadedFromFile()
+{
+    QFutureWatcher<QByteArray> *watcher = dynamic_cast< QFutureWatcher< QByteArray>* >(sender());
+    if (!watcher) {
+        // not invoked from a QFutureWatcher
+        return;
+    }
+    if (watcher->result().isNull()) {
+        // do not load empty script
+        deleteLater();
+        watcher->deleteLater();
+        return;
+    }
+    QScriptValue optionsValue = m_engine->newQObject(options, QScriptEngine::QtOwnership,
+                            QScriptEngine::ExcludeSuperClassContents | QScriptEngine::ExcludeDeleteLater);
+    m_engine->globalObject().setProperty("options", optionsValue, QScriptValue::Undeletable);
+    m_engine->globalObject().setProperty("QTimer", constructTimerClass(m_engine));
+    QObject::connect(m_engine, SIGNAL(signalHandlerException(QScriptValue)), this, SLOT(sigException(QScriptValue)));
+    KWin::MetaScripting::supplyConfig(m_engine);
+    installScriptFunctions(m_engine);
+
+    QScriptValue ret = m_engine->evaluate(watcher->result());
+
+    if (ret.isError()) {
+        sigException(ret);
+        deleteLater();
+    }
+
+    watcher->deleteLater();
     setRunning(true);
+    m_starting = false;
 }
 
 void KWin::Script::sigException(const QScriptValue& exception)
diff --git a/scripting/scripting.h b/scripting/scripting.h
index 6907cbd794..d445635251 100644
--- a/scripting/scripting.h
+++ b/scripting/scripting.h
@@ -121,9 +121,19 @@ private slots:
       * TODO: Log to file, show from notifier..
       */
     void sigException(const QScriptValue &exception);
+    /**
+     * Callback for when loadScriptFromFile has finished.
+     **/
+    void slotScriptLoadedFromFile();
 
 private:
+    /**
+     * Read the script from file into a byte array.
+     * If file cannot be read an empty byte array is returned.
+     **/
+    QByteArray loadScriptFromFile();
     QScriptEngine *m_engine;
+    bool m_starting;
 };
 
 class DeclarativeScript : public AbstractScript