Cache module properties.

The module properties look-up can take some time, so we only do it once.
On my Linux machine, this results in a ~30% speed-up of the build graph
creation.

Change-Id: I41e885915976cc89b321ea1863ecff967b42bf9c
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

3 files changed, 34 insertions, 2 deletions

diff --git a/src/lib/jsextensions/moduleproperties.cpp b/src/lib/jsextensions/moduleproperties.cpp
index e1c58f584..a8fcf57fd 100644
--- a/src/lib/jsextensions/moduleproperties.cpp
+++ b/src/lib/jsextensions/moduleproperties.cpp
@@ -108,8 +108,14 @@ QScriptValue ModuleProperties::moduleProperties(QScriptContext *context, QScript
         return context->throwError(QScriptContext::TypeError,
                                    QLatin1String("Internal error: invalid type"));
     }
+
+    ScriptEngine * const qbsEngine = static_cast<ScriptEngine *>(engine);
     const QString moduleName = context->argument(0).toString();
     const QString propertyName = context->argument(1).toString();
+    QScriptValue scriptValue
+            = qbsEngine->retrieveFromPropertyCache(moduleName, propertyName, properties);
+    if (scriptValue.isValid())
+        return scriptValue;
 
     QVariant value;
     if (oneValue)
@@ -117,8 +123,10 @@ QScriptValue ModuleProperties::moduleProperties(QScriptContext *context, QScript
     else
         value = PropertyFinder().propertyValues(properties->value(), moduleName, propertyName);
     const Property p(moduleName, propertyName, value);
-    static_cast<ScriptEngine *>(engine)->addProperty(p);
-    return engine->toScriptValue(value);
+    qbsEngine->addProperty(p);
+    scriptValue = engine->toScriptValue(value);
+    qbsEngine->addToPropertyCache(moduleName, propertyName, properties, scriptValue);
+    return scriptValue;
 }
 
 } // namespace Internal
diff --git a/src/lib/language/scriptengine.cpp b/src/lib/language/scriptengine.cpp
index 5498e4402..15291f1fd 100644
--- a/src/lib/language/scriptengine.cpp
+++ b/src/lib/language/scriptengine.cpp
@@ -31,6 +31,7 @@
 
 #include "item.h"
 #include "filecontext.h"
+#include "propertymapinternal.h"
 #include "scriptpropertyobserver.h"
 #include <tools/error.h>
 #include <tools/qbsassert.h>
@@ -106,6 +107,20 @@ void ScriptEngine::clearImportsCache()
     m_jsImportCache.clear();
 }
 
+void ScriptEngine::addToPropertyCache(const QString &moduleName, const QString &propertyName,
+        const PropertyMapConstPtr &propertyMap, QScriptValue value)
+{
+    m_propertyCache.insert(qMakePair(moduleName + QLatin1Char('.') + propertyName, propertyMap),
+                           value);
+}
+
+QScriptValue ScriptEngine::retrieveFromPropertyCache(const QString &moduleName,
+        const QString &propertyName, const PropertyMapConstPtr &propertyMap)
+{
+    return m_propertyCache.value(qMakePair(moduleName + QLatin1Char('.') + propertyName,
+                                           propertyMap));
+}
+
 static QScriptValue js_observedGet(QScriptContext *context, QScriptEngine *, void *arg)
 {
     ScriptPropertyObserver * const observer = static_cast<ScriptPropertyObserver *>(arg);
diff --git a/src/lib/language/scriptengine.h b/src/lib/language/scriptengine.h
index 3e5daf653..e39d46e25 100644
--- a/src/lib/language/scriptengine.h
+++ b/src/lib/language/scriptengine.h
@@ -31,10 +31,13 @@
 #define QBS_SCRIPTENGINE_H
 
 #include "jsimports.h"
+#include "forward_decls.h"
 #include <language/property.h>
 #include <logging/logger.h>
 #include <tools/qbs_export.h>
 
+#include <QHash>
+#include <QPair>
 #include <QScriptEngine>
 
 namespace qbs {
@@ -59,6 +62,11 @@ public:
     void clearProperties() { m_properties.clear(); }
     PropertyList properties() const { return m_properties; }
 
+    void addToPropertyCache(const QString &moduleName, const QString &propertyName,
+        const PropertyMapConstPtr &propertyMap, QScriptValue value);
+    QScriptValue retrieveFromPropertyCache(const QString &moduleName, const QString &propertyName,
+            const PropertyMapConstPtr &propertyMap);
+
     void setObservedProperty(QScriptValue &object, const QString &name, const QScriptValue &value,
                              ScriptPropertyObserver *observer);
 
@@ -67,6 +75,7 @@ private:
                        QScriptValue &targetObject);
 
     QHash<QString, QScriptValue> m_jsImportCache;
+    QHash<QPair<QString, PropertyMapConstPtr>, QScriptValue> m_propertyCache;
     PropertyList m_properties;
     Logger m_logger;
     QScriptValue m_definePropertyFunction;