Implement ArrayBuffer

This is the first class required to support typed
arrays in our JS engine.

Change-Id: I0fe1e1ca430769c171912dda207cfae772e9b9db
Reviewed-by: Simon Hausmann <[email protected]>

1 files changed, 164 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4arraybuffer.cpp b/src/qml/jsruntime/qv4arraybuffer.cpp
new file mode 100644
index 0000000000..9d24044d7c
--- /dev/null
+++ b/src/qml/jsruntime/qv4arraybuffer.cpp
@@ -0,0 +1,164 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia. For licensing terms and
+** conditions see http://qt.digia.com/licensing. For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights. These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+#include "qv4arraybuffer_p.h"
+#include "qv4typedarray_p.h"
+#include "qv4dataview_p.h"
+
+using namespace QV4;
+
+DEFINE_OBJECT_VTABLE(ArrayBufferCtor);
+DEFINE_OBJECT_VTABLE(ArrayBuffer);
+
+ArrayBufferCtor::Data::Data(ExecutionContext *scope)
+    : FunctionObject::Data(scope, QStringLiteral("ArrayBuffer"))
+{
+    setVTable(staticVTable());
+}
+
+ReturnedValue ArrayBufferCtor::construct(Managed *m, CallData *callData)
+{
+    ExecutionEngine *v4 = m->engine();
+
+    Scope scope(v4);
+    ScopedValue l(scope, callData->argument(0));
+    double dl = l->toInteger();
+    if (v4->hasException)
+        return Encode::undefined();
+    uint len = (uint)qBound(0., dl, (double)UINT_MAX);
+    if (len != dl)
+        return v4->currentContext()->throwRangeError(QLatin1String("ArrayBuffer constructor: invalid length"));
+
+    Scoped<ArrayBuffer> a(scope, v4->memoryManager->alloc<ArrayBuffer>(v4, len));
+    return a.asReturnedValue();
+}
+
+
+ReturnedValue ArrayBufferCtor::call(Managed *that, CallData *callData)
+{
+    return construct(that, callData);
+}
+
+ReturnedValue ArrayBufferCtor::method_isView(CallContext *ctx)
+{
+    QV4::Scope scope(ctx);
+    QV4::Scoped<TypedArray> a(scope, ctx->argument(0));
+    if (!!a)
+        return Encode(true);
+    QV4::Scoped<DataView> v(scope, ctx->argument(0));
+    if (!!v)
+        return Encode(true);
+    return Encode(true);
+}
+
+
+ArrayBuffer::Data::Data(ExecutionEngine *e, int length)
+    : Object::Data(e->arrayBufferClass)
+{
+    data = QTypedArrayData<char>::allocate(length + 1);
+    if (!data) {
+        data = 0;
+        e->currentContext()->throwRangeError(QStringLiteral("ArrayBuffer: out of memory"));
+        return;
+    }
+    data->size = length;
+    memset(data->data(), 0, length + 1);
+}
+
+QByteArray ArrayBuffer::asByteArray() const
+{
+    QByteArrayDataPtr ba = { d()->data };
+    ba.ptr->ref.ref();
+    return QByteArray(ba);
+}
+
+void ArrayBuffer::destroy(Managed *m)
+{
+    ArrayBuffer *b = static_cast<ArrayBuffer *>(m);
+    if (!b->d()->data->ref.deref())
+        QTypedArrayData<char>::deallocate(b->d()->data);
+}
+
+
+void ArrayBufferPrototype::init(ExecutionEngine *engine, Object *ctor)
+{
+    Scope scope(engine);
+    ScopedObject o(scope);
+    ctor->defineReadonlyProperty(engine->id_length, Primitive::fromInt32(1));
+    ctor->defineReadonlyProperty(engine->id_prototype, (o = this));
+    ctor->defineDefaultProperty(QStringLiteral("isView"), ArrayBufferCtor::method_isView, 1);
+    defineDefaultProperty(engine->id_constructor, (o = ctor));
+    defineAccessorProperty(QStringLiteral("byteLength"), method_get_byteLength, 0);
+    defineDefaultProperty(QStringLiteral("slice"), method_slice, 2);
+}
+
+ReturnedValue ArrayBufferPrototype::method_get_byteLength(CallContext *ctx)
+{
+    Scope scope(ctx);
+    Scoped<ArrayBuffer> v(scope, ctx->d()->callData->thisObject);
+    if (!v)
+        return ctx->throwTypeError();
+
+    return Encode(v->d()->data->size);
+}
+
+ReturnedValue ArrayBufferPrototype::method_slice(CallContext *ctx)
+{
+    Scope scope(ctx);
+    Scoped<ArrayBuffer> a(scope, ctx->d()->callData->thisObject);
+    if (!a)
+        return ctx->throwTypeError();
+
+    double start = ctx->d()->callData->argc > 0 ? ctx->d()->callData->args[0].toInteger() : 0;
+    double end = (ctx->d()->callData->argc < 2 || ctx->d()->callData->args[1].isUndefined()) ?
+                a->d()->data->size : ctx->d()->callData->args[1].toInteger();
+    if (scope.engine->hasException)
+        return Encode::undefined();
+
+    double first = (start < 0) ? qMax(a->d()->data->size + start, 0.) : qMin(start, (double)a->d()->data->size);
+    double final = (end < 0) ? qMax(a->d()->data->size + end, 0.) : qMin(end, (double)a->d()->data->size);
+
+    Scoped<FunctionObject> constructor(scope, a->get(scope.engine->id_constructor));
+    if (!constructor)
+        return ctx->throwTypeError();
+
+    ScopedCallData callData(scope, 1);
+    double newLen = qMax(final - first, 0.);
+    callData->args[0] = QV4::Encode(newLen);
+    QV4::Scoped<ArrayBuffer> newBuffer(scope, constructor->construct(callData));
+    if (!newBuffer || newBuffer->d()->data->size < (int)newLen)
+        return scope.engine->currentContext()->throwTypeError();
+
+    memcpy(newBuffer->d()->data->data(), a->d()->data->data() + (uint)first, newLen);
+
+    return newBuffer.asReturnedValue();
+}