LibWeb: Make ImageData GC-allocated

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/369dd42d67
Pull-request: https://github.com/SerenityOS/serenity/pull/14816
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/Forward.h

@@ -461,7 +461,6 @@ class FileWrapper;
 class HeadersWrapper;
 class HeadersIteratorWrapper;
 class IdleDeadlineWrapper;
-class ImageDataWrapper;
 class IntersectionObserverWrapper;
 class LocationObject;
 class OptionConstructor;

Userland/Libraries/LibWeb/HTML/Canvas/CanvasImageData.h

@@ -15,8 +15,8 @@ class CanvasImageData {
 public:
     virtual ~CanvasImageData() = default;
 
-    virtual RefPtr<ImageData> create_image_data(int width, int height) const = 0;
-    virtual DOM::ExceptionOr<RefPtr<ImageData>> get_image_data(int x, int y, int width, int height) const = 0;
+    virtual JS::GCPtr<ImageData> create_image_data(int width, int height) const = 0;
+    virtual DOM::ExceptionOr<JS::GCPtr<ImageData>> get_image_data(int x, int y, int width, int height) const = 0;
     virtual void put_image_data(ImageData const&, float x, float y) = 0;
 
 protected:

Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp

@@ -317,13 +317,13 @@ void CanvasRenderingContext2D::fill(Path2D& path, String const& fill_rule)
     return fill_internal(transformed_path, fill_rule);
 }
 
-RefPtr<ImageData> CanvasRenderingContext2D::create_image_data(int width, int height) const
+JS::GCPtr<ImageData> CanvasRenderingContext2D::create_image_data(int width, int height) const
 {
-    return ImageData::create_with_size(vm(), width, height);
+    return ImageData::create_with_size(global_object(), width, height);
 }
 
 // https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-getimagedata
-DOM::ExceptionOr<RefPtr<ImageData>> CanvasRenderingContext2D::get_image_data(int x, int y, int width, int height) const
+DOM::ExceptionOr<JS::GCPtr<ImageData>> CanvasRenderingContext2D::get_image_data(int x, int y, int width, int height) const
 {
     // 1. If either the sw or sh arguments are zero, then throw an "IndexSizeError" DOMException.
     if (width == 0 || height == 0)
@@ -335,7 +335,7 @@ DOM::ExceptionOr<RefPtr<ImageData>> CanvasRenderingContext2D::get_image_data(int
 
     // 3. Let imageData be a new ImageData object.
     // 4. Initialize imageData given sw, sh, settings set to settings, and defaultColorSpace set to this's color space.
-    auto image_data = ImageData::create_with_size(vm(), width, height);
+    auto image_data = ImageData::create_with_size(global_object(), width, height);
 
     // NOTE: We don't attempt to create the underlying bitmap here; if it doesn't exist, it's like copying only transparent black pixels (which is a no-op).
     if (!canvas_element().bitmap())

Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.h

@@ -70,8 +70,8 @@ public:
     virtual void fill(String const& fill_rule) override;
     virtual void fill(Path2D& path, String const& fill_rule) override;
 
-    virtual RefPtr<ImageData> create_image_data(int width, int height) const override;
-    virtual DOM::ExceptionOr<RefPtr<ImageData>> get_image_data(int x, int y, int width, int height) const override;
+    virtual JS::GCPtr<ImageData> create_image_data(int width, int height) const override;
+    virtual DOM::ExceptionOr<JS::GCPtr<ImageData>> get_image_data(int x, int y, int width, int height) const override;
     virtual void put_image_data(ImageData const&, float x, float y) override;
 
     virtual void reset_to_default_state() override;

Userland/Libraries/LibWeb/HTML/ImageData.cpp

@@ -1,18 +1,20 @@
 /*
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <LibGfx/Bitmap.h>
 #include <LibJS/Runtime/TypedArray.h>
+#include <LibWeb/Bindings/ImageDataPrototype.h>
 #include <LibWeb/HTML/ImageData.h>
+#include <LibWeb/HTML/Window.h>
 
 namespace Web::HTML {
 
-RefPtr<ImageData> ImageData::create_with_size(JS::VM& vm, int width, int height)
+JS::GCPtr<ImageData> ImageData::create_with_size(HTML::Window& window, int width, int height)
 {
-    auto& realm = *vm.current_realm();
+    auto& realm = window.realm();
 
     if (width <= 0 || height <= 0)
         return nullptr;
@@ -23,24 +25,30 @@ RefPtr<ImageData> ImageData::create_with_size(JS::VM& vm, int width, int height)
     auto data_or_error = JS::Uint8ClampedArray::create(realm, width * height * 4);
     if (data_or_error.is_error())
         return nullptr;
-    auto* data = data_or_error.release_value();
-
-    auto data_handle = JS::make_handle(data);
+    auto data = JS::NonnullGCPtr<JS::Uint8ClampedArray>(*data_or_error.release_value());
 
     auto bitmap_or_error = Gfx::Bitmap::try_create_wrapper(Gfx::BitmapFormat::RGBA8888, Gfx::IntSize(width, height), 1, width * sizeof(u32), data->data().data());
     if (bitmap_or_error.is_error())
         return nullptr;
-    return adopt_ref(*new ImageData(bitmap_or_error.release_value(), move(data_handle)));
+    return realm.heap().allocate<ImageData>(realm, window, bitmap_or_error.release_value(), move(data));
 }
 
-ImageData::ImageData(NonnullRefPtr<Gfx::Bitmap> bitmap, JS::Handle<JS::Uint8ClampedArray> data)
-    : m_bitmap(move(bitmap))
+ImageData::ImageData(HTML::Window& window, NonnullRefPtr<Gfx::Bitmap> bitmap, JS::NonnullGCPtr<JS::Uint8ClampedArray> data)
+    : PlatformObject(window.realm())
+    , m_bitmap(move(bitmap))
     , m_data(move(data))
 {
+    set_prototype(&window.ensure_web_prototype<Bindings::ImageDataPrototype>("ImageData"));
 }
 
 ImageData::~ImageData() = default;
 
+void ImageData::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_data.ptr());
+}
+
 unsigned ImageData::width() const
 {
     return m_bitmap->width();
@@ -53,12 +61,12 @@ unsigned ImageData::height() const
 
 JS::Uint8ClampedArray* ImageData::data()
 {
-    return m_data.cell();
+    return m_data;
 }
 
 const JS::Uint8ClampedArray* ImageData::data() const
 {
-    return m_data.cell();
+    return m_data;
 }
 
 }

Userland/Libraries/LibWeb/HTML/ImageData.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -7,20 +7,17 @@
 #pragma once
 
 #include <LibGfx/Forward.h>
-#include <LibJS/Heap/Handle.h>
-#include <LibWeb/Bindings/Wrappable.h>
+#include <LibWeb/Bindings/PlatformObject.h>
 
 namespace Web::HTML {
 
-class ImageData
-    : public RefCounted<ImageData>
-    , public Bindings::Wrappable {
+class ImageData final : public Bindings::PlatformObject {
+    WEB_PLATFORM_OBJECT(ImageData, Bindings::PlatformObject);
+
 public:
-    using WrapperType = Bindings::ImageDataWrapper;
+    static JS::GCPtr<ImageData> create_with_size(HTML::Window&, int width, int height);
 
-    static RefPtr<ImageData> create_with_size(JS::VM&, int width, int height);
-
-    ~ImageData();
+    virtual ~ImageData() override;
 
     unsigned width() const;
     unsigned height() const;
@@ -32,10 +29,14 @@ public:
     const JS::Uint8ClampedArray* data() const;
 
 private:
-    explicit ImageData(NonnullRefPtr<Gfx::Bitmap>, JS::Handle<JS::Uint8ClampedArray>);
+    explicit ImageData(HTML::Window&, NonnullRefPtr<Gfx::Bitmap>, JS::NonnullGCPtr<JS::Uint8ClampedArray>);
+
+    virtual void visit_edges(Cell::Visitor&) override;
 
     NonnullRefPtr<Gfx::Bitmap> m_bitmap;
-    JS::Handle<JS::Uint8ClampedArray> m_data;
+    JS::NonnullGCPtr<JS::Uint8ClampedArray> m_data;
 };
 
 }
+
+WRAPPER_HACK(ImageData, Web::HTML)

Userland/Libraries/LibWeb/idl_files.cmake

@@ -140,7 +140,7 @@ libweb_js_wrapper(HTML/HTMLTrackElement NO_INSTANCE)
 libweb_js_wrapper(HTML/HTMLUListElement NO_INSTANCE)
 libweb_js_wrapper(HTML/HTMLUnknownElement NO_INSTANCE)
 libweb_js_wrapper(HTML/HTMLVideoElement NO_INSTANCE)
-libweb_js_wrapper(HTML/ImageData)
+libweb_js_wrapper(HTML/ImageData NO_INSTANCE)
 libweb_js_wrapper(HTML/MessageChannel NO_INSTANCE)
 libweb_js_wrapper(HTML/MessageEvent NO_INSTANCE)
 libweb_js_wrapper(HTML/MessagePort NO_INSTANCE)