QML: add a memory pool to the Json* classes.

The memory pool is not too efficient, but will keep objects from
leaking.

Change-Id: I68a55bc7a6ea56463652245abeea8954b693c1d7
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>

src/libs/qmljs/qmljsbundle.cpp

@@ -250,6 +250,8 @@ QStringList QmlBundle::maybeReadTrie(Trie &trie, Utils::JsonObjectValue *config,
 
 bool QmlBundle::readFrom(QString path, QStringList *errors)
 {
+    Utils::JsonMemoryPool pool;
+
     using namespace Utils;
     QFile f(path);
     if (!f.open(QIODevice::ReadOnly | QIODevice::Text)) {
@@ -257,7 +259,7 @@ bool QmlBundle::readFrom(QString path, QStringList *errors)
             (*errors) << QString::fromLatin1("Could not open file at %1 .").arg(path);
         return false;
     }
-    JsonObjectValue *config = JsonValue::create(QString::fromUtf8(f.readAll()))->toObject();
+    JsonObjectValue *config = JsonValue::create(QString::fromUtf8(f.readAll()), &pool)->toObject();
     if (config == 0) {
         if (errors)
             (*errors) << QString::fromLatin1("Could not parse json object in file at %1 .").arg(path);

src/libs/utils/json.cpp

@@ -39,6 +39,11 @@
 
 using namespace Utils;
 
+JsonMemoryPool::~JsonMemoryPool()
+{
+    foreach (char *obj, _objs)
+        delete[] obj;
+}
 
 JsonValue::JsonValue(Kind kind)
     : m_kind(kind)
@@ -47,7 +52,7 @@ JsonValue::JsonValue(Kind kind)
 JsonValue::~JsonValue()
 {}
 
-JsonValue *JsonValue::create(const QString &s)
+JsonValue *JsonValue::create(const QString &s, JsonMemoryPool *pool)
 {
     QScriptEngine engine;
     QScriptValue jsonParser = engine.evaluate(QLatin1String("JSON.parse"));
@@ -55,9 +60,18 @@ JsonValue *JsonValue::create(const QString &s)
     if (engine.hasUncaughtException() || !value.isValid())
         return 0;
 
-    return build(value.toVariant());
+    return build(value.toVariant(), pool);
 }
 
+void *JsonValue::operator new(size_t size, JsonMemoryPool *pool)
+{ return pool->allocate(size); }
+
+void JsonValue::operator delete(void *)
+{ }
+
+void JsonValue::operator delete(void *, JsonMemoryPool *)
+{ }
+
 QString JsonValue::kindToString(JsonValue::Kind kind)
 {
     if (kind == String)
@@ -78,39 +92,39 @@ QString JsonValue::kindToString(JsonValue::Kind kind)
     return QLatin1String("unkown");
 }
 
-JsonValue *JsonValue::build(const QVariant &variant)
+JsonValue *JsonValue::build(const QVariant &variant, JsonMemoryPool *pool)
 {
     switch (variant.type()) {
 
     case QVariant::List: {
-        JsonArrayValue *newValue = new JsonArrayValue;
+        JsonArrayValue *newValue = new (pool) JsonArrayValue;
         foreach (const QVariant &element, variant.toList())
-            newValue->addElement(build(element));
+            newValue->addElement(build(element, pool));
         return newValue;
     }
 
     case QVariant::Map: {
-        JsonObjectValue *newValue = new JsonObjectValue;
+        JsonObjectValue *newValue = new (pool) JsonObjectValue;
         const QVariantMap variantMap = variant.toMap();
         for (QVariantMap::const_iterator it = variantMap.begin(); it != variantMap.end(); ++it)
-            newValue->addMember(it.key(), build(it.value()));
+            newValue->addMember(it.key(), build(it.value(), pool));
         return newValue;
     }
 
     case QVariant::String:
-        return new JsonStringValue(variant.toString());
+        return new (pool) JsonStringValue(variant.toString());
 
     case QVariant::Int:
-        return new JsonIntValue(variant.toInt());
+        return new (pool) JsonIntValue(variant.toInt());
 
     case QVariant::Double:
-        return new JsonDoubleValue(variant.toDouble());
+        return new (pool) JsonDoubleValue(variant.toDouble());
 
     case QVariant::Bool:
-        return new JsonBooleanValue(variant.toBool());
+        return new (pool) JsonBooleanValue(variant.toBool());
 
     case QVariant::Invalid:
-        return new JsonNullValue;
+        return new (pool) JsonNullValue;
 
     default:
         break;
@@ -727,7 +741,7 @@ JsonSchema *JsonSchemaManager::parseSchema(const QString &schemaFileName) const
     FileReader reader;
     if (reader.fetch(schemaFileName, QIODevice::Text)) {
         const QString &contents = QString::fromUtf8(reader.data());
-        JsonValue *json = JsonValue::create(contents);
+        JsonValue *json = JsonValue::create(contents, &m_pool);
         if (json && json->kind() == JsonValue::Object)
             return new JsonSchema(json->toObject(), this);
     }

src/libs/utils/json.h

@@ -49,6 +49,22 @@ class JsonArrayValue;
 class JsonBooleanValue;
 class JsonNullValue;
 
+class QTCREATOR_UTILS_EXPORT JsonMemoryPool
+{
+public:
+    ~JsonMemoryPool();
+
+    inline void *allocate(size_t size)
+    {
+        char *obj = new char[size];
+        _objs.append(obj);
+        return obj;
+    }
+
+private:
+    QVector<char *> _objs;
+};
+
 /*!
  * \brief The JsonValue class
  */
@@ -79,13 +95,16 @@ public:
     virtual JsonBooleanValue *toBoolean() { return 0; }
     virtual JsonNullValue *toNull() { return 0; }
 
-    static JsonValue *create(const QString &s);
+    static JsonValue *create(const QString &s, JsonMemoryPool *pool);
+    void *operator new(size_t size, JsonMemoryPool *pool);
+    void operator delete(void *);
+    void operator delete(void *, JsonMemoryPool *);
 
 protected:
     JsonValue(Kind kind);
 
 private:
-    static JsonValue *build(const QVariant &varixant);
+    static JsonValue *build(const QVariant &varixant, JsonMemoryPool *pool);
 
     Kind m_kind;
 };
@@ -398,6 +417,7 @@ private:
 
     QStringList m_searchPaths;
     mutable QHash<QString, JsonSchemaData> m_schemas;
+    mutable JsonMemoryPool m_pool;
 };
 
 } // namespace Utils