Implement support for SharedArrayBuffer

We'll still need to hook this up with Worker threads to become
useful.

Change-Id: Iedae7307edd76368aeba163731856ebe9b32c6b6
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

7 files changed, 164 insertions, 43 deletions

diff --git a/src/qml/jsruntime/qv4arraybuffer.cpp b/src/qml/jsruntime/qv4arraybuffer.cpp
index dc8bce12a0..9b5a983fdf 100644
--- a/src/qml/jsruntime/qv4arraybuffer.cpp
+++ b/src/qml/jsruntime/qv4arraybuffer.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtQml module of the Qt Toolkit.
@@ -45,14 +45,46 @@
 
 using namespace QV4;
 
+DEFINE_OBJECT_VTABLE(SharedArrayBufferCtor);
 DEFINE_OBJECT_VTABLE(ArrayBufferCtor);
+DEFINE_OBJECT_VTABLE(SharedArrayBuffer);
 DEFINE_OBJECT_VTABLE(ArrayBuffer);
 
+void Heap::SharedArrayBufferCtor::init(QV4::ExecutionContext *scope)
+{
+    Heap::FunctionObject::init(scope, QStringLiteral("SharedArrayBuffer"));
+}
+
 void Heap::ArrayBufferCtor::init(QV4::ExecutionContext *scope)
 {
     Heap::FunctionObject::init(scope, QStringLiteral("ArrayBuffer"));
 }
 
+ReturnedValue SharedArrayBufferCtor::virtualCallAsConstructor(const FunctionObject *f, const Value *argv, int argc, const Value *newTarget)
+{
+    Scope scope(f);
+    if (newTarget->isUndefined())
+        return scope.engine->throwTypeError();
+
+    qint64 len = argc ? argv[0].toIndex() : 0;
+    if (scope.engine->hasException)
+        return Encode::undefined();
+    if (len < 0 || len >= INT_MAX)
+        return scope.engine->throwRangeError(QStringLiteral("SharedArrayBuffer: Invalid length."));
+
+    Scoped<SharedArrayBuffer> a(scope, scope.engine->memoryManager->allocate<SharedArrayBuffer>(len));
+    if (scope.engine->hasException)
+        return Encode::undefined();
+
+    return a->asReturnedValue();
+}
+
+ReturnedValue SharedArrayBufferCtor::virtualCall(const FunctionObject *f, const Value *, const Value *, int)
+{
+    return f->engine()->throwTypeError();
+}
+
+
 ReturnedValue ArrayBufferCtor::virtualCallAsConstructor(const FunctionObject *f, const Value *argv, int argc, const Value *)
 {
     ExecutionEngine *v4 = f->engine();
@@ -73,12 +105,6 @@ ReturnedValue ArrayBufferCtor::virtualCallAsConstructor(const FunctionObject *f,
     return a->asReturnedValue();
 }
 
-
-ReturnedValue ArrayBufferCtor::virtualCall(const FunctionObject *f, const Value *, const Value *, int)
-{
-    return f->engine()->throwTypeError();
-}
-
 ReturnedValue ArrayBufferCtor::method_isView(const FunctionObject *, const Value *, const Value *argv, int argc)
 {
     if (argc < 1)
@@ -92,7 +118,7 @@ ReturnedValue ArrayBufferCtor::method_isView(const FunctionObject *, const Value
 }
 
 
-void Heap::ArrayBuffer::init(size_t length)
+void Heap::SharedArrayBuffer::init(size_t length)
 {
     Object::init();
     if (length < UINT_MAX)
@@ -103,16 +129,18 @@ void Heap::ArrayBuffer::init(size_t length)
     }
     data->size = int(length);
     memset(data->data(), 0, length + 1);
+    isShared = true;
 }
 
-void Heap::ArrayBuffer::init(const QByteArray& array)
+void Heap::SharedArrayBuffer::init(const QByteArray& array)
 {
     Object::init();
     data = const_cast<QByteArray&>(array).data_ptr();
     data->ref.ref();
+    isShared = true;
 }
 
-void Heap::ArrayBuffer::destroy()
+void Heap::SharedArrayBuffer::destroy()
 {
     if (data && !data->ref.deref())
         QTypedArrayData<char>::deallocate(data);
@@ -145,66 +173,100 @@ void ArrayBuffer::detach() {
 }
 
 
-void ArrayBufferPrototype::init(ExecutionEngine *engine, Object *ctor)
+void SharedArrayBufferPrototype::init(ExecutionEngine *engine, Object *ctor)
 {
     Scope scope(engine);
     ScopedObject o(scope);
     ctor->defineReadonlyConfigurableProperty(engine->id_length(), Primitive::fromInt32(1));
     ctor->defineReadonlyProperty(engine->id_prototype(), (o = this));
-    ctor->defineDefaultProperty(QStringLiteral("isView"), ArrayBufferCtor::method_isView, 1);
     ctor->addSymbolSpecies();
 
     defineDefaultProperty(engine->id_constructor(), (o = ctor));
     defineAccessorProperty(QStringLiteral("byteLength"), method_get_byteLength, nullptr);
     defineDefaultProperty(QStringLiteral("slice"), method_slice, 2);
-    defineDefaultProperty(QStringLiteral("toString"), method_toString, 0);
-    ScopedString name(scope, engine->newString(QStringLiteral("ArrayBuffer")));
+    ScopedString name(scope, engine->newString(QStringLiteral("SharedArrayBuffer")));
     defineReadonlyConfigurableProperty(scope.engine->symbol_toStringTag(), name);
 }
 
-ReturnedValue ArrayBufferPrototype::method_get_byteLength(const FunctionObject *b, const Value *thisObject, const Value *, int)
+ReturnedValue SharedArrayBufferPrototype::method_get_byteLength(const FunctionObject *b, const Value *thisObject, const Value *, int)
 {
-    const ArrayBuffer *a = thisObject->as<ArrayBuffer>();
-    if (!a || a->isDetachedBuffer() || a->isSharedArrayBuffer())
+    const SharedArrayBuffer *a = thisObject->as<SharedArrayBuffer>();
+    if (!a || a->isDetachedBuffer() || !a->isSharedArrayBuffer())
         return b->engine()->throwTypeError();
 
     return Encode(a->d()->data->size);
 }
 
-ReturnedValue ArrayBufferPrototype::method_slice(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc)
+ReturnedValue SharedArrayBufferPrototype::method_slice(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc)
 {
-    ExecutionEngine *v4 = b->engine();
-    const ArrayBuffer *a = thisObject->as<ArrayBuffer>();
-    if (!a || a->isDetachedBuffer() || a->isSharedArrayBuffer())
-        return v4->throwTypeError();
+    return slice(b, thisObject, argv, argc, true);
+}
+
+ReturnedValue SharedArrayBufferPrototype::slice(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc, bool shared)
+{
+    Scope scope(b);
+    const SharedArrayBuffer *a = thisObject->as<SharedArrayBuffer>();
+    if (!a || a->isDetachedBuffer() || (a->isSharedArrayBuffer() != shared))
+        return scope.engine->throwTypeError();
 
     double start = argc > 0 ? argv[0].toInteger() : 0;
     double end = (argc < 2 || argv[1].isUndefined()) ?
                 a->d()->data->size : argv[1].toInteger();
-    if (v4->hasException)
+    if (scope.hasException())
         return QV4::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);
 
-    Scope scope(v4);
-    const FunctionObject *constructor = a->speciesConstructor(scope, scope.engine->arrayBufferCtor());
+    const FunctionObject *constructor = a->speciesConstructor(scope, shared ? scope.engine->sharedArrayBufferCtor() : scope.engine->arrayBufferCtor());
     if (!constructor)
-        return v4->throwTypeError();
+        return scope.engine->throwTypeError();
 
     double newLen = qMax(final - first, 0.);
     ScopedValue argument(scope, QV4::Encode(newLen));
-    QV4::Scoped<ArrayBuffer> newBuffer(scope, constructor->callAsConstructor(argument, 1));
+    QV4::Scoped<SharedArrayBuffer> newBuffer(scope, constructor->callAsConstructor(argument, 1));
     if (!newBuffer || newBuffer->d()->data->size < (int)newLen ||
-        newBuffer->isDetachedBuffer() || newBuffer->isSharedArrayBuffer() ||
+        newBuffer->isDetachedBuffer() || (newBuffer->isSharedArrayBuffer() != shared) ||
         newBuffer->sameValue(*a) ||
         a->isDetachedBuffer())
-        return v4->throwTypeError();
+        return scope.engine->throwTypeError();
 
     memcpy(newBuffer->d()->data->data(), a->d()->data->data() + (uint)first, newLen);
     return newBuffer->asReturnedValue();
 }
 
+
+void ArrayBufferPrototype::init(ExecutionEngine *engine, Object *ctor)
+{
+    Scope scope(engine);
+    ScopedObject o(scope);
+    ctor->defineReadonlyConfigurableProperty(engine->id_length(), Primitive::fromInt32(1));
+    ctor->defineReadonlyProperty(engine->id_prototype(), (o = this));
+    ctor->defineDefaultProperty(QStringLiteral("isView"), ArrayBufferCtor::method_isView, 1);
+    ctor->addSymbolSpecies();
+
+    defineDefaultProperty(engine->id_constructor(), (o = ctor));
+    defineAccessorProperty(QStringLiteral("byteLength"), method_get_byteLength, nullptr);
+    defineDefaultProperty(QStringLiteral("slice"), method_slice, 2);
+    defineDefaultProperty(QStringLiteral("toString"), method_toString, 0);
+    ScopedString name(scope, engine->newString(QStringLiteral("ArrayBuffer")));
+    defineReadonlyConfigurableProperty(scope.engine->symbol_toStringTag(), name);
+}
+
+ReturnedValue ArrayBufferPrototype::method_get_byteLength(const FunctionObject *f, const Value *thisObject, const Value *, int)
+{
+    const ArrayBuffer *a = thisObject->as<ArrayBuffer>();
+    if (!a || a->isDetachedBuffer() || a->isSharedArrayBuffer())
+        return f->engine()->throwTypeError();
+
+    return Encode(a->d()->data->size);
+}
+
+ReturnedValue ArrayBufferPrototype::method_slice(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc)
+{
+    return slice(b, thisObject, argv, argc, false);
+}
+
 ReturnedValue ArrayBufferPrototype::method_toString(const FunctionObject *b, const Value *thisObject, const Value *, int)
 {
     ExecutionEngine *v4 = b->engine();
diff --git a/src/qml/jsruntime/qv4arraybuffer_p.h b/src/qml/jsruntime/qv4arraybuffer_p.h
index 036d141c2f..8344fa2554 100644
--- a/src/qml/jsruntime/qv4arraybuffer_p.h
+++ b/src/qml/jsruntime/qv4arraybuffer_p.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2018 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtQml module of the Qt Toolkit.
@@ -59,59 +59,107 @@ namespace QV4 {
 
 namespace Heap {
 
-struct ArrayBufferCtor : FunctionObject {
+struct SharedArrayBufferCtor : FunctionObject {
     void init(QV4::ExecutionContext *scope);
 };
 
-struct Q_QML_PRIVATE_EXPORT ArrayBuffer : Object {
+struct ArrayBufferCtor : SharedArrayBufferCtor {
+    void init(QV4::ExecutionContext *scope);
+};
+
+struct Q_QML_PRIVATE_EXPORT SharedArrayBuffer : Object {
     void init(size_t length);
     void init(const QByteArray& array);
     void destroy();
     QTypedArrayData<char> *data;
+    bool isShared;
 
     uint byteLength() const { return data ? data->size : 0; }
 
+    bool isDetachedBuffer() const { return !data; }
+    bool isSharedArrayBuffer() const { return isShared; }
+};
+
+struct Q_QML_PRIVATE_EXPORT ArrayBuffer : SharedArrayBuffer {
+    void init(size_t length) {
+        SharedArrayBuffer::init(length);
+        isShared = false;
+    }
+    void init(const QByteArray& array) {
+        SharedArrayBuffer::init(array);
+        isShared = false;
+    }
     void detachArrayBuffer() {
         if (data && !data->ref.deref())
             QTypedArrayData<char>::deallocate(data);
         data = nullptr;
     }
-    bool isDetachedBuffer() const { return !data; }
-    bool isSharedArrayBuffer() const { return false; }
 };
 
+
 }
 
-struct ArrayBufferCtor: FunctionObject
+struct SharedArrayBufferCtor : FunctionObject
 {
-    V4_OBJECT2(ArrayBufferCtor, FunctionObject)
+    V4_OBJECT2(SharedArrayBufferCtor, FunctionObject)
 
     static ReturnedValue virtualCallAsConstructor(const FunctionObject *f, const Value *argv, int argc, const Value *);
     static ReturnedValue virtualCall(const FunctionObject *f, const Value *thisObject, const Value *argv, int argc);
+};
+
+struct ArrayBufferCtor : SharedArrayBufferCtor
+{
+    V4_OBJECT2(ArrayBufferCtor, SharedArrayBufferCtor)
+
+    static ReturnedValue virtualCallAsConstructor(const FunctionObject *f, const Value *argv, int argc, const Value *);
 
     static ReturnedValue method_isView(const FunctionObject *, const Value *thisObject, const Value *argv, int argc);
+};
 
+struct Q_QML_PRIVATE_EXPORT SharedArrayBuffer : Object
+{
+    V4_OBJECT2(SharedArrayBuffer, Object)
+    V4_NEEDS_DESTROY
+    V4_PROTOTYPE(sharedArrayBufferPrototype)
+
+    QByteArray asByteArray() const;
+    uint byteLength() const { return d()->byteLength(); }
+    char *data() { Q_ASSERT(d()->data); return d()->data->data(); }
+    const char *constData() { Q_ASSERT(d()->data); return d()->data->data(); }
+
+    bool isShared() { return d()->data->ref.isShared(); }
+    bool isDetachedBuffer() const { return !d()->data; }
+    bool isSharedArrayBuffer() const { return d()->isShared; }
 };
 
-struct Q_QML_PRIVATE_EXPORT ArrayBuffer : Object
+struct Q_QML_PRIVATE_EXPORT ArrayBuffer : SharedArrayBuffer
 {
-    V4_OBJECT2(ArrayBuffer, Object)
+    V4_OBJECT2(ArrayBuffer, SharedArrayBuffer)
     V4_NEEDS_DESTROY
     V4_PROTOTYPE(arrayBufferPrototype)
 
     QByteArray asByteArray() const;
     uint byteLength() const { return d()->byteLength(); }
     char *data() { detach(); return d()->data ? d()->data->data() : nullptr; }
+    // ### is that detach needed?
     const char *constData() { detach(); return d()->data ? d()->data->data() : nullptr; }
 
     bool isShared() { return d()->data && d()->data->ref.isShared(); }
-    bool isDetachedBuffer() const { return !d()->data; }
-    bool isSharedArrayBuffer() const { return false; }
     void detach();
     void detachArrayBuffer() { d()->detachArrayBuffer(); }
 };
 
-struct ArrayBufferPrototype: Object
+struct SharedArrayBufferPrototype : Object
+{
+    void init(ExecutionEngine *engine, Object *ctor);
+
+    static ReturnedValue method_get_byteLength(const FunctionObject *, const Value *thisObject, const Value *argv, int argc);
+    static ReturnedValue method_slice(const FunctionObject *, const Value *thisObject, const Value *argv, int argc);
+
+    static ReturnedValue slice(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc, bool shared);
+};
+
+struct ArrayBufferPrototype : SharedArrayBufferPrototype
 {
     void init(ExecutionEngine *engine, Object *ctor);
 
diff --git a/src/qml/jsruntime/qv4dataview.cpp b/src/qml/jsruntime/qv4dataview.cpp
index 3f0e2fd1a7..d52b9488ac 100644
--- a/src/qml/jsruntime/qv4dataview.cpp
+++ b/src/qml/jsruntime/qv4dataview.cpp
@@ -75,7 +75,7 @@ static uint toIndex(ExecutionEngine *e, const Value &v)
 ReturnedValue DataViewCtor::virtualCallAsConstructor(const FunctionObject *f, const Value *argv, int argc, const Value *newTarget)
 {
     Scope scope(f->engine());
-    Scoped<ArrayBuffer> buffer(scope, argc ? argv[0] : Primitive::undefinedValue());
+    Scoped<SharedArrayBuffer> buffer(scope, argc ? argv[0] : Primitive::undefinedValue());
     if (!newTarget || !buffer)
         return scope.engine->throwTypeError();
 
diff --git a/src/qml/jsruntime/qv4dataview_p.h b/src/qml/jsruntime/qv4dataview_p.h
index 6a9f865c0f..199a6f9f80 100644
--- a/src/qml/jsruntime/qv4dataview_p.h
+++ b/src/qml/jsruntime/qv4dataview_p.h
@@ -64,7 +64,7 @@ struct DataViewCtor : FunctionObject {
 };
 
 #define DataViewMembers(class, Member) \
-    Member(class, Pointer, ArrayBuffer *, buffer) \
+    Member(class, Pointer, SharedArrayBuffer *, buffer) \
     Member(class, NoMark, uint, byteLength) \
     Member(class, NoMark, uint, byteOffset)
 
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 5ccf3d4f6e..c1a4b67d60 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -494,6 +494,10 @@ ExecutionEngine::ExecutionEngine(QJSEngine *jsEngine)
 
     // typed arrays
 
+    jsObjects[SharedArrayBuffer_Ctor] = memoryManager->allocate<SharedArrayBufferCtor>(global);
+    jsObjects[SharedArrayBufferProto] = memoryManager->allocate<SharedArrayBufferPrototype>();
+    static_cast<SharedArrayBufferPrototype *>(sharedArrayBufferPrototype())->init(this, sharedArrayBufferCtor());
+
     jsObjects[ArrayBuffer_Ctor] = memoryManager->allocate<ArrayBufferCtor>(global);
     jsObjects[ArrayBufferProto] = memoryManager->allocate<ArrayBufferPrototype>();
     static_cast<ArrayBufferPrototype *>(arrayBufferPrototype())->init(this, arrayBufferCtor());
@@ -539,6 +543,7 @@ ExecutionEngine::ExecutionEngine(QJSEngine *jsEngine)
     globalObject->defineDefaultProperty(QStringLiteral("TypeError"), *typeErrorCtor());
     globalObject->defineDefaultProperty(QStringLiteral("URIError"), *uRIErrorCtor());
 
+    globalObject->defineDefaultProperty(QStringLiteral("SharedArrayBuffer"), *sharedArrayBufferCtor());
     globalObject->defineDefaultProperty(QStringLiteral("ArrayBuffer"), *arrayBufferCtor());
     globalObject->defineDefaultProperty(QStringLiteral("DataView"), *dataViewCtor());
     globalObject->defineDefaultProperty(QStringLiteral("Set"), *setCtor());
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index e11e607bd1..0f4a4a75a2 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -162,6 +162,7 @@ public:
 #if QT_CONFIG(qml_sequence_object)
         SequenceProto,
 #endif
+        SharedArrayBufferProto,
         ArrayBufferProto,
         DataViewProto,
         SetProto,
@@ -193,6 +194,7 @@ public:
         SyntaxError_Ctor,
         TypeError_Ctor,
         URIError_Ctor,
+        SharedArrayBuffer_Ctor,
         ArrayBuffer_Ctor,
         DataView_Ctor,
         Set_Ctor,
@@ -229,6 +231,7 @@ public:
     FunctionObject *syntaxErrorCtor() const { return reinterpret_cast<FunctionObject *>(jsObjects + SyntaxError_Ctor); }
     FunctionObject *typeErrorCtor() const { return reinterpret_cast<FunctionObject *>(jsObjects + TypeError_Ctor); }
     FunctionObject *uRIErrorCtor() const { return reinterpret_cast<FunctionObject *>(jsObjects + URIError_Ctor); }
+    FunctionObject *sharedArrayBufferCtor() const { return reinterpret_cast<FunctionObject *>(jsObjects + SharedArrayBuffer_Ctor); }
     FunctionObject *arrayBufferCtor() const { return reinterpret_cast<FunctionObject *>(jsObjects + ArrayBuffer_Ctor); }
     FunctionObject *dataViewCtor() const { return reinterpret_cast<FunctionObject *>(jsObjects + DataView_Ctor); }
     FunctionObject *setCtor() const { return reinterpret_cast<FunctionObject *>(jsObjects + Set_Ctor); }
@@ -262,6 +265,7 @@ public:
     Object *sequencePrototype() const { return reinterpret_cast<Object *>(jsObjects + SequenceProto); }
 #endif
 
+    Object *sharedArrayBufferPrototype() const { return reinterpret_cast<Object *>(jsObjects + SharedArrayBufferProto); }
     Object *arrayBufferPrototype() const { return reinterpret_cast<Object *>(jsObjects + ArrayBufferProto); }
     Object *dataViewPrototype() const { return reinterpret_cast<Object *>(jsObjects + DataViewProto); }
     Object *setPrototype() const { return reinterpret_cast<Object *>(jsObjects + SetProto); }
diff --git a/src/qml/jsruntime/qv4global_p.h b/src/qml/jsruntime/qv4global_p.h
index e3b3423a9d..b4dac505cd 100644
--- a/src/qml/jsruntime/qv4global_p.h
+++ b/src/qml/jsruntime/qv4global_p.h
@@ -190,6 +190,7 @@ namespace Heap {
     struct RegExp;
     struct EvalFunction;
 
+    struct SharedArrayBuffer;
     struct ArrayBuffer;
     struct DataView;
     struct TypedArray;
@@ -236,6 +237,7 @@ struct RegExpObject;
 struct RegExp;
 struct EvalFunction;
 
+struct SharedArrayBuffer;
 struct ArrayBuffer;
 struct DataView;
 struct TypedArray;