From 1c406294fc426a2d083e7d5f30f7e4e97ef4a794 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 14 Mar 2020 13:15:11 +0100
Subject: [PATCH] LibWeb: Start implementing basic JavaScript DOM bindings

This patch introduces the Wrapper and Wrappable classes.

Node now inherits from Wrappable, and can be wrapped in a GC-allocated
Bindings::NodeWrapper object. The only property we expose right now is
the very simple nodeName property.

When a Document's JS::Interpreter is first instantiated, we add a
"document" property with a DocumentWrapper object to the global object.

This is pretty cool! :^)
---
 Base/home/anon/www/dom.html                   | 12 +++++++
 Base/home/anon/www/welcome.html               |  1 +
 Libraries/LibWeb/Bindings/DocumentWrapper.cpp | 29 +++++++++++++++++
 Libraries/LibWeb/Bindings/DocumentWrapper.h   | 21 +++++++++++++
 Libraries/LibWeb/Bindings/NodeWrapper.cpp     | 20 ++++++++++++
 Libraries/LibWeb/Bindings/NodeWrapper.h       | 23 ++++++++++++++
 Libraries/LibWeb/Bindings/Wrappable.cpp       | 18 +++++++++++
 Libraries/LibWeb/Bindings/Wrappable.h         | 31 +++++++++++++++++++
 Libraries/LibWeb/Bindings/Wrapper.h           | 19 ++++++++++++
 Libraries/LibWeb/DOM/Document.cpp             |  3 ++
 Libraries/LibWeb/DOM/Document.h               |  2 ++
 Libraries/LibWeb/DOM/Node.h                   |  5 ++-
 Libraries/LibWeb/Forward.h                    | 10 ++++++
 Libraries/LibWeb/Makefile                     |  3 ++
 14 files changed, 196 insertions(+), 1 deletion(-)
 create mode 100644 Base/home/anon/www/dom.html
 create mode 100644 Libraries/LibWeb/Bindings/DocumentWrapper.cpp
 create mode 100644 Libraries/LibWeb/Bindings/DocumentWrapper.h
 create mode 100644 Libraries/LibWeb/Bindings/NodeWrapper.cpp
 create mode 100644 Libraries/LibWeb/Bindings/NodeWrapper.h
 create mode 100644 Libraries/LibWeb/Bindings/Wrappable.cpp
 create mode 100644 Libraries/LibWeb/Bindings/Wrappable.h
 create mode 100644 Libraries/LibWeb/Bindings/Wrapper.h
diff --git a/Base/home/anon/www/dom.html b/Base/home/anon/www/dom.html
new file mode 100644
index 0000000000..0c6a15dfad
--- /dev/null
+++ b/Base/home/anon/www/dom.html
@@ -0,0 +1,12 @@
+<!DOCTYPE>
+<html>
+    <head></head>
+    <body>
+        <div id="foo"></div>
+    <script>
+        alert(document.nodeName);
+        //var e = document.getElementById("foo");
+        //alert(e.nodeName);
+    </script>
+    </body>
+</html>
diff --git a/Base/home/anon/www/welcome.html b/Base/home/anon/www/welcome.html
index 6f7f3a3a78..4f2d30a013 100644
--- a/Base/home/anon/www/welcome.html
+++ b/Base/home/anon/www/welcome.html
@@ -23,6 +23,7 @@ h1 {
     <p>This is a very simple browser built on the LibWeb engine.</p>
     <p>Some small test pages:</p>
     <ul>
+        <li><a href="dom.html">simple DOM JS test</a></li>
         <li><a href="alert.html">alert() test</a></li>
         <li><a href="small.html">small</a></li>
         <li><a href="first-child.html">:first-child</a></li>
diff --git a/Libraries/LibWeb/Bindings/DocumentWrapper.cpp b/Libraries/LibWeb/Bindings/DocumentWrapper.cpp
new file mode 100644
index 0000000000..91836d7c8e
--- /dev/null
+++ b/Libraries/LibWeb/Bindings/DocumentWrapper.cpp
@@ -0,0 +1,29 @@
+#include <LibJS/PrimitiveString.h>
+#include <LibJS/Value.h>
+#include <LibWeb/Bindings/DocumentWrapper.h>
+#include <LibWeb/DOM/Document.h>
+
+namespace Web {
+namespace Bindings {
+
+DocumentWrapper::DocumentWrapper(Document& document)
+    : NodeWrapper(document)
+{
+}
+
+DocumentWrapper::~DocumentWrapper()
+{
+}
+
+Document& DocumentWrapper::node()
+{
+    return static_cast<Document&>(NodeWrapper::node());
+}
+
+const Document& DocumentWrapper::node() const
+{
+    return static_cast<const Document&>(NodeWrapper::node());
+}
+
+}
+}
diff --git a/Libraries/LibWeb/Bindings/DocumentWrapper.h b/Libraries/LibWeb/Bindings/DocumentWrapper.h
new file mode 100644
index 0000000000..931720c696
--- /dev/null
+++ b/Libraries/LibWeb/Bindings/DocumentWrapper.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <LibWeb/Bindings/NodeWrapper.h>
+
+namespace Web {
+namespace Bindings {
+
+class DocumentWrapper : public NodeWrapper {
+public:
+    explicit DocumentWrapper(Document&);
+    virtual ~DocumentWrapper() override;
+
+    Document& node();
+    const Document& node() const;
+
+private:
+    virtual const char* class_name() const override { return "Document"; }
+};
+
+}
+}
diff --git a/Libraries/LibWeb/Bindings/NodeWrapper.cpp b/Libraries/LibWeb/Bindings/NodeWrapper.cpp
new file mode 100644
index 0000000000..9aaa9b21a4
--- /dev/null
+++ b/Libraries/LibWeb/Bindings/NodeWrapper.cpp
@@ -0,0 +1,20 @@
+#include <LibJS/PrimitiveString.h>
+#include <LibJS/Value.h>
+#include <LibWeb/Bindings/NodeWrapper.h>
+#include <LibWeb/DOM/Node.h>
+
+namespace Web {
+namespace Bindings {
+
+NodeWrapper::NodeWrapper(Node& node)
+    : m_node(node)
+{
+    put("nodeName", JS::js_string(heap(), node.tag_name()));
+}
+
+NodeWrapper::~NodeWrapper()
+{
+}
+
+}
+}
diff --git a/Libraries/LibWeb/Bindings/NodeWrapper.h b/Libraries/LibWeb/Bindings/NodeWrapper.h
new file mode 100644
index 0000000000..b7a24b94b7
--- /dev/null
+++ b/Libraries/LibWeb/Bindings/NodeWrapper.h
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <LibWeb/Bindings/Wrapper.h>
+
+namespace Web {
+namespace Bindings {
+
+class NodeWrapper : public Wrapper {
+public:
+    explicit NodeWrapper(Node&);
+    virtual ~NodeWrapper() override;
+
+    Node& node() { return *m_node; }
+    const Node& node() const { return *m_node; }
+
+private:
+    virtual const char* class_name() const override { return "Node"; }
+
+    NonnullRefPtr<Node> m_node;
+};
+
+}
+}
diff --git a/Libraries/LibWeb/Bindings/Wrappable.cpp b/Libraries/LibWeb/Bindings/Wrappable.cpp
new file mode 100644
index 0000000000..2245e14723
--- /dev/null
+++ b/Libraries/LibWeb/Bindings/Wrappable.cpp
@@ -0,0 +1,18 @@
+#include <LibWeb/Bindings/Wrappable.h>
+#include <LibWeb/Bindings/Wrapper.h>
+
+namespace Web {
+namespace Bindings {
+
+Wrappable::~Wrappable()
+{
+}
+
+void Wrappable::set_wrapper(Wrapper& wrapper)
+{
+    ASSERT(!m_wrapper);
+    m_wrapper = wrapper.make_weak_ptr();
+}
+
+}
+}
diff --git a/Libraries/LibWeb/Bindings/Wrappable.h b/Libraries/LibWeb/Bindings/Wrappable.h
new file mode 100644
index 0000000000..4531f63935
--- /dev/null
+++ b/Libraries/LibWeb/Bindings/Wrappable.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <AK/WeakPtr.h>
+#include <LibJS/Heap.h>
+#include <LibWeb/Forward.h>
+
+namespace Web {
+namespace Bindings {
+
+class Wrappable {
+public:
+    virtual ~Wrappable();
+
+    void set_wrapper(Wrapper&);
+    Wrapper* wrapper() { return m_wrapper; }
+    const Wrapper* wrapper() const { return m_wrapper; }
+
+private:
+    WeakPtr<Wrapper> m_wrapper;
+};
+
+template<class NativeObject>
+inline Wrapper* wrap(JS::Heap& heap, NativeObject& native_object)
+{
+    if (!native_object.wrapper())
+        native_object.set_wrapper(*heap.allocate<typename NativeObject::WrapperType>(native_object));
+    return native_object.wrapper();
+}
+
+}
+}
diff --git a/Libraries/LibWeb/Bindings/Wrapper.h b/Libraries/LibWeb/Bindings/Wrapper.h
new file mode 100644
index 0000000000..680200eaab
--- /dev/null
+++ b/Libraries/LibWeb/Bindings/Wrapper.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <AK/NonnullRefPtr.h>
+#include <AK/Weakable.h>
+#include <LibJS/Object.h>
+#include <LibWeb/Forward.h>
+
+namespace Web {
+namespace Bindings {
+
+class Wrapper
+    : public JS::Object
+    , public Weakable<Wrapper> {
+protected:
+    explicit Wrapper() {}
+};
+
+}
+}
diff --git a/Libraries/LibWeb/DOM/Document.cpp b/Libraries/LibWeb/DOM/Document.cpp
index 8e25cbf64d..669f399047 100644
--- a/Libraries/LibWeb/DOM/Document.cpp
+++ b/Libraries/LibWeb/DOM/Document.cpp
@@ -31,6 +31,7 @@
 #include <LibGUI/MessageBox.h>
 #include <LibJS/GlobalObject.h>
 #include <LibJS/Interpreter.h>
+#include <LibWeb/Bindings/DocumentWrapper.h>
 #include <LibWeb/CSS/StyleResolver.h>
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/DOM/DocumentType.h>
@@ -346,6 +347,8 @@ JS::Interpreter& Document::interpreter()
             GUI::MessageBox::show(arguments[0].to_string(), "Alert", GUI::MessageBox::Type::Information);
             return JS::js_undefined();
         });
+
+        m_interpreter->global_object().put("document", wrap(m_interpreter->heap(), *this));
     }
     return *m_interpreter;
 }
diff --git a/Libraries/LibWeb/DOM/Document.h b/Libraries/LibWeb/DOM/Document.h
index bdfe6e6cb9..b4fef21bb2 100644
--- a/Libraries/LibWeb/DOM/Document.h
+++ b/Libraries/LibWeb/DOM/Document.h
@@ -51,6 +51,8 @@ class StyleSheet;
 
 class Document : public ParentNode {
 public:
+    using WrapperType = Bindings::DocumentWrapper;
+
     Document();
     virtual ~Document() override;
 
diff --git a/Libraries/LibWeb/DOM/Node.h b/Libraries/LibWeb/DOM/Node.h
index 51a48bdffd..3cf67681a3 100644
--- a/Libraries/LibWeb/DOM/Node.h
+++ b/Libraries/LibWeb/DOM/Node.h
@@ -30,6 +30,7 @@
 #include <AK/RefPtr.h>
 #include <AK/String.h>
 #include <AK/Vector.h>
+#include <LibWeb/Bindings/Wrappable.h>
 #include <LibWeb/TreeNode.h>
 
 namespace Web {
@@ -53,7 +54,9 @@ class LayoutNode;
 class StyleResolver;
 class StyleProperties;
 
-class Node : public TreeNode<Node> {
+class Node
+    : public TreeNode<Node>
+    , public Bindings::Wrappable {
 public:
     virtual ~Node();
 
diff --git a/Libraries/LibWeb/Forward.h b/Libraries/LibWeb/Forward.h
index d700b317c3..8c87919e5b 100644
--- a/Libraries/LibWeb/Forward.h
+++ b/Libraries/LibWeb/Forward.h
@@ -34,4 +34,14 @@ class Frame;
 class HtmlView;
 class Node;
 
+namespace Bindings {
+
+class DocumentWrapper;
+class NodeWrapper;
+class Wrappable;
+class Wrapper;
+
+}
+
+
 }
diff --git a/Libraries/LibWeb/Makefile b/Libraries/LibWeb/Makefile
index 96acd12078..2a4601ae0b 100644
--- a/Libraries/LibWeb/Makefile
+++ b/Libraries/LibWeb/Makefile
@@ -1,4 +1,7 @@
 LIBWEB_OBJS = \
+    Bindings/Wrappable.o \
+    Bindings/NodeWrapper.o \
+    Bindings/DocumentWrapper.o \
     CSS/DefaultStyleSheetSource.o \
     CSS/PropertyID.o \
     CSS/Selector.o \
