LibWeb: Make Web::Page GC-allocated

This is a first step towards removing the various Page& and Page*
we have littering the engine with "trust me bro" safety guarantees.

Co-Authored-By: Andreas Kling <kling@serenityos.org>

Userland/Libraries/LibWeb/Page/Page.cpp

@@ -23,13 +23,25 @@
 
 namespace Web {
 
-Page::Page(PageClient& client)
+JS::NonnullGCPtr<Page> Page::create(JS::VM& vm, JS::NonnullGCPtr<PageClient> page_client)
+{
+    return vm.heap().allocate_without_realm<Page>(page_client);
+}
+
+Page::Page(JS::NonnullGCPtr<PageClient> client)
     : m_client(client)
 {
 }
 
 Page::~Page() = default;
 
+void Page::visit_edges(JS::Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_top_level_traversable);
+    visitor.visit(m_client);
+}
+
 HTML::BrowsingContext& Page::focused_context()
 {
     if (m_focused_context)
@@ -56,13 +68,13 @@ void Page::load_html(StringView html)
 
 Gfx::Palette Page::palette() const
 {
-    return m_client.palette();
+    return m_client->palette();
 }
 
 // https://w3c.github.io/csswg-drafts/cssom-view-1/#web-exposed-screen-area
 CSSPixelRect Page::web_exposed_screen_area() const
 {
-    auto device_pixel_rect = m_client.screen_rect();
+    auto device_pixel_rect = m_client->screen_rect();
     auto scale = client().device_pixels_per_css_pixel();
     return {
         device_pixel_rect.x().value() / scale,
@@ -74,7 +86,7 @@ CSSPixelRect Page::web_exposed_screen_area() const
 
 CSS::PreferredColorScheme Page::preferred_color_scheme() const
 {
-    return m_client.preferred_color_scheme();
+    return m_client->preferred_color_scheme();
 }
 
 CSSPixelPoint Page::device_to_css_point(DevicePixelPoint point) const
@@ -210,12 +222,12 @@ static ResponseType spin_event_loop_until_dialog_closed(PageClient& client, Opti
 void Page::did_request_alert(String const& message)
 {
     m_pending_dialog = PendingDialog::Alert;
-    m_client.page_did_request_alert(message);
+    m_client->page_did_request_alert(message);
 
     if (!message.is_empty())
         m_pending_dialog_text = message;
 
-    spin_event_loop_until_dialog_closed(m_client, m_pending_alert_response);
+    spin_event_loop_until_dialog_closed(*m_client, m_pending_alert_response);
 }
 
 void Page::alert_closed()
@@ -230,12 +242,12 @@ void Page::alert_closed()
 bool Page::did_request_confirm(String const& message)
 {
     m_pending_dialog = PendingDialog::Confirm;
-    m_client.page_did_request_confirm(message);
+    m_client->page_did_request_confirm(message);
 
     if (!message.is_empty())
         m_pending_dialog_text = message;
 
-    return spin_event_loop_until_dialog_closed(m_client, m_pending_confirm_response);
+    return spin_event_loop_until_dialog_closed(*m_client, m_pending_confirm_response);
 }
 
 void Page::confirm_closed(bool accepted)
@@ -250,12 +262,12 @@ void Page::confirm_closed(bool accepted)
 Optional<String> Page::did_request_prompt(String const& message, String const& default_)
 {
     m_pending_dialog = PendingDialog::Prompt;
-    m_client.page_did_request_prompt(message, default_);
+    m_client->page_did_request_prompt(message, default_);
 
     if (!message.is_empty())
         m_pending_dialog_text = message;
 
-    return spin_event_loop_until_dialog_closed(m_client, m_pending_prompt_response);
+    return spin_event_loop_until_dialog_closed(*m_client, m_pending_prompt_response);
 }
 
 void Page::prompt_closed(Optional<String> response)
@@ -273,11 +285,11 @@ void Page::dismiss_dialog()
     case PendingDialog::None:
         break;
     case PendingDialog::Alert:
-        m_client.page_did_request_accept_dialog();
+        m_client->page_did_request_accept_dialog();
         break;
     case PendingDialog::Confirm:
     case PendingDialog::Prompt:
-        m_client.page_did_request_dismiss_dialog();
+        m_client->page_did_request_dismiss_dialog();
         break;
     }
 }
@@ -290,7 +302,7 @@ void Page::accept_dialog()
     case PendingDialog::Alert:
     case PendingDialog::Confirm:
     case PendingDialog::Prompt:
-        m_client.page_did_request_accept_dialog();
+        m_client->page_did_request_accept_dialog();
         break;
     }
 }
@@ -301,7 +313,7 @@ void Page::did_request_color_picker(WeakPtr<HTML::HTMLInputElement> target, Colo
         m_pending_non_blocking_dialog = PendingNonBlockingDialog::ColorPicker;
         m_pending_non_blocking_dialog_target = move(target);
 
-        m_client.page_did_request_color_picker(current_color);
+        m_client->page_did_request_color_picker(current_color);
     }
 }
 

Userland/Libraries/LibWeb/Page/Page.h

@@ -1,7 +1,8 @@
 /*
- * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2021-2022, Linus Groh <linusg@serenityos.org>
  * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2023, Shannon Booth <shannon@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -36,12 +37,14 @@ namespace Web {
 
 class PageClient;
 
-class Page : public Weakable<Page> {
+class Page final
-    AK_MAKE_NONCOPYABLE(Page);
+    : public JS::Cell
-    AK_MAKE_NONMOVABLE(Page);
+    , public Weakable<Page> {
+    JS_CELL(Page, JS::Cell);
 
 public:
-    explicit Page(PageClient&);
+    static JS::NonnullGCPtr<Page> create(JS::VM&, JS::NonnullGCPtr<PageClient>);
+
     ~Page();
 
     PageClient& client() { return m_client; }
@@ -152,13 +155,16 @@ public:
     bool pdf_viewer_supported() const { return m_pdf_viewer_supported; }
 
 private:
+    explicit Page(JS::NonnullGCPtr<PageClient>);
+    virtual void visit_edges(Visitor&) override;
+
     JS::GCPtr<HTML::HTMLMediaElement> media_context_menu_element();
 
-    PageClient& m_client;
+    JS::NonnullGCPtr<PageClient> m_client;
 
     WeakPtr<HTML::BrowsingContext> m_focused_context;
 
-    JS::Handle<HTML::TraversableNavigable> m_top_level_traversable;
+    JS::GCPtr<HTML::TraversableNavigable> m_top_level_traversable;
 
     // FIXME: Enable this by default once CORS preflight checks are supported.
     bool m_same_origin_policy_enabled { false };

Userland/Libraries/LibWeb/SVG/SVGDecodedImageData.cpp

@@ -57,7 +57,7 @@ private:
 ErrorOr<NonnullRefPtr<SVGDecodedImageData>> SVGDecodedImageData::create(Page& host_page, AK::URL const& url, ByteBuffer data)
 {
     auto page_client = SVGPageClient::create(Bindings::main_thread_vm(), host_page);
-    auto page = make<Page>(*page_client);
+    auto page = Page::create(Bindings::main_thread_vm(), *page_client);
     page_client->m_svg_page = page.ptr();
     page->set_top_level_traversable(MUST(Web::HTML::TraversableNavigable::create_a_fresh_top_level_traversable(*page, AK::URL("about:blank"))));
     JS::NonnullGCPtr<HTML::Navigable> navigable = page->top_level_traversable();
@@ -98,10 +98,10 @@ ErrorOr<NonnullRefPtr<SVGDecodedImageData>> SVGDecodedImageData::create(Page& ho
 
     MUST(document->append_child(*svg_root));
 
-    return adopt_nonnull_ref_or_enomem(new (nothrow) SVGDecodedImageData(move(page), move(page_client), move(document), move(svg_root)));
+    return adopt_nonnull_ref_or_enomem(new (nothrow) SVGDecodedImageData(page, move(page_client), move(document), move(svg_root)));
 }
 
-SVGDecodedImageData::SVGDecodedImageData(NonnullOwnPtr<Page> page, JS::Handle<SVGPageClient> page_client, JS::Handle<DOM::Document> document, JS::Handle<SVG::SVGSVGElement> root_element)
+SVGDecodedImageData::SVGDecodedImageData(JS::NonnullGCPtr<Page> page, JS::Handle<SVGPageClient> page_client, JS::Handle<DOM::Document> document, JS::Handle<SVG::SVGSVGElement> root_element)
     : m_page(move(page))
     , m_page_client(move(page_client))
     , m_document(move(document))

Userland/Libraries/LibWeb/SVG/SVGDecodedImageData.h

@@ -32,12 +32,12 @@ public:
 
 private:
     class SVGPageClient;
-    SVGDecodedImageData(NonnullOwnPtr<Page>, JS::Handle<SVGPageClient>, JS::Handle<DOM::Document>, JS::Handle<SVG::SVGSVGElement>);
+    SVGDecodedImageData(JS::NonnullGCPtr<Page>, JS::Handle<SVGPageClient>, JS::Handle<DOM::Document>, JS::Handle<SVG::SVGSVGElement>);
 
     RefPtr<Gfx::Bitmap> render(Gfx::IntSize) const;
     mutable RefPtr<Gfx::ImmutableBitmap> m_immutable_bitmap;
 
-    NonnullOwnPtr<Page> m_page;
+    JS::Handle<Page> m_page;
     JS::Handle<SVGPageClient> m_page_client;
 
     JS::Handle<DOM::Document> m_document;

Userland/Services/WebContent/PageClient.cpp

@@ -8,6 +8,7 @@
 
 #include <LibGfx/ShareableBitmap.h>
 #include <LibGfx/SystemTheme.h>
+#include <LibWeb/Bindings/MainThreadVM.h>
 #include <LibWeb/CSS/SystemColor.h>
 #include <LibWeb/Cookie/ParsedCookie.h>
 #include <LibWeb/DOM/Attr.h>
@@ -46,7 +47,7 @@ JS::NonnullGCPtr<PageClient> PageClient::create(JS::VM& vm, PageHost& page_host,
 
 PageClient::PageClient(PageHost& owner, u64 id)
     : m_owner(owner)
-    , m_page(make<Web::Page>(*this))
+    , m_page(Web::Page::create(Web::Bindings::main_thread_vm(), *this))
     , m_id(id)
 {
     setup_palette();
@@ -56,6 +57,12 @@ PageClient::PageClient(PageHost& owner, u64 id)
     });
 }
 
+void PageClient::visit_edges(JS::Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_page);
+}
+
 ConnectionFromClient& PageClient::client() const
 {
     return m_owner.client();

Userland/Services/WebContent/PageClient.h

@@ -61,6 +61,8 @@ public:
 private:
     PageClient(PageHost&, u64 id);
 
+    virtual void visit_edges(JS::Cell::Visitor&) override;
+
     // ^PageClient
     virtual bool is_connection_open() const override;
     virtual Gfx::Palette palette() const override;
@@ -131,7 +133,7 @@ private:
     ConnectionFromClient& client() const;
 
     PageHost& m_owner;
-    NonnullOwnPtr<Web::Page> m_page;
+    JS::NonnullGCPtr<Web::Page> m_page;
     RefPtr<Gfx::PaletteImpl> m_palette_impl;
     Web::DevicePixelRect m_screen_rect;
     Web::DevicePixelSize m_content_size;

Userland/Services/WebWorker/PageHost.cpp

@@ -5,6 +5,7 @@
  */
 
 #include <LibJS/Runtime/VM.h>
+#include <LibWeb/Bindings/MainThreadVM.h>
 #include <WebWorker/ConnectionFromClient.h>
 #include <WebWorker/PageHost.h>
 
@@ -75,9 +76,15 @@ void PageHost::request_file(Web::FileRequest request)
 
 PageHost::PageHost(ConnectionFromClient& client)
     : m_client(client)
-    , m_page(make<Web::Page>(*this))
+    , m_page(Web::Page::create(Web::Bindings::main_thread_vm(), *this))
 {
     setup_palette();
 }
 
+void PageHost::visit_edges(JS::Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_page);
+}
+
 }

Userland/Services/WebWorker/PageHost.h

@@ -33,11 +33,12 @@ public:
 
 private:
     explicit PageHost(ConnectionFromClient&);
+    virtual void visit_edges(JS::Cell::Visitor&) override;
 
     void setup_palette();
 
     ConnectionFromClient& m_client;
-    NonnullOwnPtr<Web::Page> m_page;
+    JS::NonnullGCPtr<Web::Page> m_page;
     RefPtr<Gfx::PaletteImpl> m_palette_impl;
 };