QML Engine: Share data for ArrayBuffer created from QByteArray.

ExecutionEngine performs shallow copy of internal data for ArrayBuffer
created from QByteArray.

Change-Id: I514cd9708a7fbe9a989937fac62d00b464d7362d
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>
Reviewed-by: Valery Kotov <kotov.valery@gmail.com>
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4arraybuffer.cpp b/src/qml/jsruntime/qv4arraybuffer.cpp
index e42fcdc4fd..11664f1194 100644
--- a/src/qml/jsruntime/qv4arraybuffer.cpp
+++ b/src/qml/jsruntime/qv4arraybuffer.cpp
@@ -95,6 +95,13 @@ Heap::ArrayBuffer::ArrayBuffer(ExecutionEngine *e, size_t length)
     memset(data->data(), 0, length + 1);
 }
 
+Heap::ArrayBuffer::ArrayBuffer(ExecutionEngine *e, const QByteArray& array)
+    : Heap::Object(e->emptyClass, e->arrayBufferPrototype.asObject())
+    , data(const_cast<QByteArray&>(array).data_ptr())
+{
+    data->ref.ref();
+}
+
 Heap::ArrayBuffer::~ArrayBuffer()
 {
     if (!data->ref.deref())
@@ -108,6 +115,25 @@ QByteArray ArrayBuffer::asByteArray() const
     return QByteArray(ba);
 }
 
+void ArrayBuffer::detach() {
+    if (!d()->data->ref.isShared())
+        return;
+
+    QTypedArrayData<char> *oldData = d()->data;
+
+    d()->data = QTypedArrayData<char>::allocate(oldData->size + 1);
+    if (!d()->data) {
+        engine()->throwRangeError(QStringLiteral("ArrayBuffer: out of memory"));
+        return;
+    }
+
+    memcpy(d()->data->data(), oldData->data(), oldData->size + 1);
+
+    if (!oldData->ref.deref())
+        QTypedArrayData<char>::deallocate(oldData);
+}
+
+
 void ArrayBufferPrototype::init(ExecutionEngine *engine, Object *ctor)
 {
     Scope scope(engine);