LibJS: Add "constructor" property to constructor prototypes

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/f07f8d5a44f

Libraries/LibJS/AST.cpp

@@ -32,6 +32,7 @@
 #include <LibJS/Interpreter.h>
 #include <LibJS/Runtime/Array.h>
 #include <LibJS/Runtime/Error.h>
+#include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/NativeFunction.h>
 #include <LibJS/Runtime/PrimitiveString.h>
 #include <LibJS/Runtime/ScriptFunction.h>

Libraries/LibJS/Forward.h

@@ -29,17 +29,24 @@
 namespace JS {
 
 class ASTNode;
+class ArrayConstructor;
+class BooleanConstructor;
 class Cell;
+class DateConstructor;
 class Error;
+class ErrorConstructor;
 class Exception;
 class Expression;
 class Function;
+class FunctionConstructor;
 class GlobalObject;
 class HandleImpl;
 class Heap;
 class HeapBlock;
 class Interpreter;
+class NumberConstructor;
 class Object;
+class ObjectConstructor;
 class PrimitiveString;
 class ScopeNode;
 class Shape;

Libraries/LibJS/Interpreter.cpp

@@ -227,4 +227,14 @@ Value Interpreter::throw_exception(Exception* exception)
     return {};
 }
 
+GlobalObject& Interpreter::global_object()
+{
+    return static_cast<GlobalObject&>(*m_global_object);
+}
+
+const GlobalObject& Interpreter::global_object() const
+{
+    return static_cast<const GlobalObject&>(*m_global_object);
+}
+
 }

Libraries/LibJS/Interpreter.h

@@ -83,8 +83,8 @@ public:
 
     Value run(const Statement&, ArgumentVector = {}, ScopeType = ScopeType::Block);
 
-    Object& global_object() { return *m_global_object; }
-    const Object& global_object() const { return *m_global_object; }
+    GlobalObject& global_object();
+    const GlobalObject& global_object() const;
 
     Heap& heap() { return m_heap; }
 

Libraries/LibJS/Runtime/GlobalObject.cpp

@@ -43,6 +43,14 @@
 
 namespace JS {
 
+template<typename ConstructorType>
+void GlobalObject::add_constructor(const FlyString& property_name, ConstructorType*& constructor, Object& prototype)
+{
+    constructor = heap().allocate<ConstructorType>();
+    prototype.put("constructor", constructor);
+    put(property_name, constructor);
+}
+
 GlobalObject::GlobalObject()
 {
     put_native_function("gc", gc);
@@ -54,20 +62,34 @@ GlobalObject::GlobalObject()
     put("undefined", js_undefined());
 
     put("console", heap().allocate<ConsoleObject>());
-    put("Date", heap().allocate<DateConstructor>());
-    put("Error", heap().allocate<ErrorConstructor>());
-    put("Function", heap().allocate<FunctionConstructor>());
     put("Math", heap().allocate<MathObject>());
-    put("Object", heap().allocate<ObjectConstructor>());
-    put("Array", heap().allocate<ArrayConstructor>());
-    put("Boolean", heap().allocate<BooleanConstructor>());
-    put("Number", heap().allocate<NumberConstructor>());
+
+    add_constructor("Array", m_array_constructor, *interpreter().array_prototype());
+    add_constructor("Boolean", m_boolean_constructor, *interpreter().boolean_prototype());
+    add_constructor("Date", m_date_constructor, *interpreter().date_prototype());
+    add_constructor("Error", m_error_constructor, *interpreter().error_prototype());
+    add_constructor("Function", m_function_constructor, *interpreter().function_prototype());
+    add_constructor("Number", m_number_constructor, *interpreter().number_prototype());
+    add_constructor("Object", m_object_constructor, *interpreter().object_prototype());
 }
 
 GlobalObject::~GlobalObject()
 {
 }
 
+void GlobalObject::visit_children(Visitor& visitor)
+{
+    Object::visit_children(visitor);
+
+    visitor.visit(m_array_constructor);
+    visitor.visit(m_boolean_constructor);
+    visitor.visit(m_date_constructor);
+    visitor.visit(m_error_constructor);
+    visitor.visit(m_function_constructor);
+    visitor.visit(m_number_constructor);
+    visitor.visit(m_object_constructor);
+}
+
 Value GlobalObject::gc(Interpreter& interpreter)
 {
     dbg() << "Forced garbage collection requested!";

Libraries/LibJS/Runtime/GlobalObject.h

@@ -24,7 +24,6 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-
 #pragma once
 
 #include <LibJS/Runtime/Object.h>
@@ -36,11 +35,31 @@ public:
     explicit GlobalObject();
     virtual ~GlobalObject() override;
 
+    ArrayConstructor* array_constructor() { return m_array_constructor; }
+    BooleanConstructor* boolean_constructor() { return m_boolean_constructor; }
+    DateConstructor* date_constructor() { return m_date_constructor; }
+    ErrorConstructor* error_constructor() { return m_error_constructor; }
+    FunctionConstructor* function_constructor() { return m_function_constructor; }
+    NumberConstructor* number_constructor() { return m_number_constructor; };
+    ObjectConstructor* object_constructor() { return m_object_constructor; }
+
 private:
     virtual const char* class_name() const override { return "GlobalObject"; }
+    virtual void visit_children(Visitor&) override;
 
     static Value gc(Interpreter&);
     static Value is_nan(Interpreter&);
+
+    template<typename ConstructorType>
+    void add_constructor(const FlyString& property_name, ConstructorType*&, Object& prototype);
+
+    ArrayConstructor* m_array_constructor { nullptr };
+    BooleanConstructor* m_boolean_constructor { nullptr };
+    DateConstructor* m_date_constructor { nullptr };
+    ErrorConstructor* m_error_constructor { nullptr };
+    FunctionConstructor* m_function_constructor { nullptr };
+    NumberConstructor* m_number_constructor { nullptr };
+    ObjectConstructor* m_object_constructor { nullptr };
 };
 
 }

Libraries/LibJS/Runtime/Object.cpp

@@ -28,6 +28,7 @@
 #include <LibJS/Heap/Heap.h>
 #include <LibJS/Interpreter.h>
 #include <LibJS/Runtime/Array.h>
+#include <LibJS/Runtime/GlobalObject.h>
 #include <LibJS/Runtime/NativeFunction.h>
 #include <LibJS/Runtime/NativeProperty.h>
 #include <LibJS/Runtime/Object.h>

Libraries/LibJS/Tests/Object.prototype.constructor.js

@@ -0,0 +1,28 @@
+try {
+    assert(Array.prototype.constructor === Array)
+    assert(Boolean.prototype.constructor === Boolean)
+    assert(Date.prototype.constructor === Date)
+    assert(Error.prototype.constructor === Error)
+    assert(Function.prototype.constructor === Function)
+    assert(Number.prototype.constructor === Number)
+    assert(Object.prototype.constructor === Object)
+
+    o = {}
+    assert(o.constructor === Object)
+
+    o = new Object
+    assert(o.constructor === Object)
+
+    a = []
+    assert(a.constructor === Array)
+
+    a = new Array
+    assert(a.constructor === Array)
+
+    n = new Number(3)
+    assert(n.constructor === Number)
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}