LibWeb: Implement "browsing context group" concept from the HTML spec

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/8ead228202

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -144,6 +144,7 @@ set(SOURCES
     HTML/AttributeNames.cpp
     HTML/BrowsingContext.cpp
     HTML/BrowsingContextContainer.cpp
+    HTML/BrowsingContextGroup.cpp
     HTML/Canvas/CanvasDrawImage.cpp
     HTML/Canvas/CanvasPath.cpp
     HTML/Canvas/CanvasState.cpp

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -98,7 +98,7 @@ static NonnullRefPtr<HTML::BrowsingContext> obtain_a_browsing_context_to_use_for
 
     // 3. Let newBrowsingContext be the result of creating a new top-level browsing context.
     VERIFY(browsing_context.page());
-    auto new_browsing_context = HTML::BrowsingContext::create_a_new_browsing_context(*browsing_context.page(), nullptr, nullptr);
+    auto new_browsing_context = HTML::BrowsingContext::create_a_new_top_level_browsing_context(*browsing_context.page());
 
     // FIXME: 4. If navigationCOOP's value is "same-origin-plurs-COEP", then set newBrowsingContext's group's
     //           cross-origin isolation mode to either "logical" or "concrete". The choice of which is implementation-defined.

Userland/Libraries/LibWeb/Forward.h

@@ -211,6 +211,7 @@ class DOMRectReadOnly;
 namespace Web::HTML {
 class BrowsingContext;
 class BrowsingContextContainer;
+class BrowsingContextGroup;
 class CanvasRenderingContext2D;
 class ClassicScript;
 class CloseEvent;

Userland/Libraries/LibWeb/HTML/BrowsingContext.cpp

@@ -9,6 +9,7 @@
 #include <LibWeb/DOM/HTMLCollection.h>
 #include <LibWeb/HTML/BrowsingContext.h>
 #include <LibWeb/HTML/BrowsingContextContainer.h>
+#include <LibWeb/HTML/BrowsingContextGroup.h>
 #include <LibWeb/HTML/CrossOrigin/CrossOriginOpenerPolicy.h>
 #include <LibWeb/HTML/EventLoop/EventLoop.h>
 #include <LibWeb/HTML/HTMLAnchorElement.h>
@@ -86,8 +87,18 @@ HTML::Origin determine_the_origin(BrowsingContext const& browsing_context, Optio
     return url_origin(*url);
 }
 
+// https://html.spec.whatwg.org/multipage/browsers.html#creating-a-new-top-level-browsing-context
+NonnullRefPtr<BrowsingContext> BrowsingContext::create_a_new_top_level_browsing_context(Web::Page& page)
+{
+    // 1. Let group be the result of creating a new browsing context group.
+    auto group = BrowsingContextGroup::create_a_new_browsing_context_group(page);
+
+    // 2. Return group's browsing context set[0].
+    return *group->browsing_context_set().begin();
+}
+
 // https://html.spec.whatwg.org/multipage/browsers.html#creating-a-new-browsing-context
-NonnullRefPtr<BrowsingContext> BrowsingContext::create_a_new_browsing_context(Page& page, JS::GCPtr<DOM::Document> creator, JS::GCPtr<DOM::Element> embedder)
+NonnullRefPtr<BrowsingContext> BrowsingContext::create_a_new_browsing_context(Page& page, JS::GCPtr<DOM::Document> creator, JS::GCPtr<DOM::Element> embedder, BrowsingContextGroup&)
 {
     // 1. Let browsingContext be a new browsing context.
     BrowsingContextContainer* container = (embedder && is<BrowsingContextContainer>(*embedder)) ? static_cast<BrowsingContextContainer*>(embedder.ptr()) : nullptr;
@@ -805,4 +816,33 @@ void BrowsingContext::scroll_offset_did_change()
     doc->pending_scroll_event_targets().append(*doc);
 }
 
+BrowsingContextGroup* BrowsingContext::group()
+{
+    return m_group;
+}
+
+void BrowsingContext::set_group(BrowsingContextGroup* group)
+{
+    m_group = group;
+}
+
+// https://html.spec.whatwg.org/multipage/browsers.html#bcg-remove
+void BrowsingContext::remove()
+{
+    // 1. Assert: browsingContext's group is non-null, because a browsing context only gets discarded once.
+    VERIFY(group());
+
+    // 2. Let group be browsingContext's group.
+    NonnullRefPtr<BrowsingContextGroup> group = *this->group();
+
+    // 3. Set browsingContext's group to null.
+    set_group(nullptr);
+
+    // 4. Remove browsingContext from group's browsing context set.
+    group->browsing_context_set().remove(*this);
+
+    // 5. If group's browsing context set is empty, then remove group from the user agent's browsing context group set.
+    // NOTE: This is done by ~BrowsingContextGroup() when the refcount reaches 0.
+}
+
 }

Userland/Libraries/LibWeb/HTML/BrowsingContext.h

@@ -26,7 +26,8 @@ namespace Web::HTML {
 
 class BrowsingContext : public TreeNode<BrowsingContext> {
 public:
-    static NonnullRefPtr<BrowsingContext> create_a_new_browsing_context(Page&, JS::GCPtr<DOM::Document> creator, JS::GCPtr<DOM::Element> embedder);
+    static NonnullRefPtr<BrowsingContext> create_a_new_browsing_context(Page&, JS::GCPtr<DOM::Document> creator, JS::GCPtr<DOM::Element> embedder, BrowsingContextGroup&);
+    static NonnullRefPtr<BrowsingContext> create_a_new_top_level_browsing_context(Page&);
 
     ~BrowsingContext();
 
@@ -124,6 +125,12 @@ public:
     // https://html.spec.whatwg.org/multipage/dom.html#still-on-its-initial-about:blank-document
     bool still_on_its_initial_about_blank_document() const;
 
+    BrowsingContextGroup* group();
+    void set_group(BrowsingContextGroup*);
+
+    // https://html.spec.whatwg.org/multipage/browsers.html#bcg-remove
+    void remove();
+
 private:
     explicit BrowsingContext(Page&, HTML::BrowsingContextContainer*);
 
@@ -161,6 +168,9 @@ private:
 
     HashMap<AK::URL, size_t> m_frame_nesting_levels;
     String m_name;
+
+    // https://html.spec.whatwg.org/multipage/browsers.html#tlbc-group
+    RefPtr<BrowsingContextGroup> m_group;
 };
 
 HTML::Origin determine_the_origin(BrowsingContext const& browsing_context, Optional<AK::URL> url, SandboxingFlagSet sandbox_flags, Optional<HTML::Origin> invocation_origin);

Userland/Libraries/LibWeb/HTML/BrowsingContextContainer.cpp

@@ -9,6 +9,7 @@
 #include <LibWeb/DOM/Event.h>
 #include <LibWeb/HTML/BrowsingContext.h>
 #include <LibWeb/HTML/BrowsingContextContainer.h>
+#include <LibWeb/HTML/BrowsingContextGroup.h>
 #include <LibWeb/HTML/Origin.h>
 #include <LibWeb/Page/Page.h>
 
@@ -25,18 +26,19 @@ BrowsingContextContainer::~BrowsingContextContainer() = default;
 void BrowsingContextContainer::create_new_nested_browsing_context()
 {
     // 1. Let group be element's node document's browsing context's top-level browsing context's group.
-    // FIXME: We do not have a concept of "browsing context groups" yet.
-    auto* group = document().browsing_context();
-    if (!group)
-        return;
+    VERIFY(document().browsing_context());
+    auto* group = document().browsing_context()->top_level_browsing_context().group();
 
+    // NOTE: The spec assumes that `group` is non-null here.
+    VERIFY(group);
     VERIFY(group->page());
 
     // 2. Let browsingContext be the result of creating a new browsing context with element's node document, element, and group.
     // 3. Set element's nested browsing context to browsingContext.
-    m_nested_browsing_context = BrowsingContext::create_a_new_browsing_context(*group->page(), document(), *this);
-    group->append_child(*m_nested_browsing_context);
-    m_nested_browsing_context->set_frame_nesting_levels(group->frame_nesting_levels());
+    m_nested_browsing_context = BrowsingContext::create_a_new_browsing_context(*group->page(), document(), *this, *group);
+
+    document().browsing_context()->append_child(*m_nested_browsing_context);
+    m_nested_browsing_context->set_frame_nesting_levels(document().browsing_context()->frame_nesting_levels());
     m_nested_browsing_context->register_frame_nesting(document().url());
 
     // 4. If element has a name attribute, then set browsingContext's name to the value of this attribute.

Userland/Libraries/LibWeb/HTML/BrowsingContextGroup.cpp

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/HTML/BrowsingContext.h>
+#include <LibWeb/HTML/BrowsingContextGroup.h>
+
+namespace Web::HTML {
+
+// https://html.spec.whatwg.org/multipage/browsers.html#browsing-context-group-set
+static HashTable<BrowsingContextGroup*>& user_agent_browsing_context_group_set()
+{
+    static HashTable<BrowsingContextGroup*> set;
+    return set;
+}
+
+BrowsingContextGroup::BrowsingContextGroup(Web::Page& page)
+    : m_page(page)
+{
+    user_agent_browsing_context_group_set().set(this);
+}
+
+BrowsingContextGroup::~BrowsingContextGroup()
+{
+    user_agent_browsing_context_group_set().remove(this);
+}
+
+// https://html.spec.whatwg.org/multipage/browsers.html#creating-a-new-browsing-context-group
+NonnullRefPtr<BrowsingContextGroup> BrowsingContextGroup::create_a_new_browsing_context_group(Web::Page& page)
+{
+    // 1. Let group be a new browsing context group.
+    // 2. Append group to the user agent's browsing context group set.
+    auto group = adopt_ref(*new BrowsingContextGroup(page));
+
+    // 3. Let browsingContext be the result of creating a new browsing context with null, null, and group.
+    auto browsing_context = BrowsingContext::create_a_new_browsing_context(page, nullptr, nullptr, group);
+
+    // 4. Append browsingContext to group.
+    group->append(move(browsing_context));
+
+    // 5. Return group.
+    return group;
+}
+
+// https://html.spec.whatwg.org/multipage/browsers.html#bcg-append
+void BrowsingContextGroup::append(BrowsingContext& browsing_context)
+{
+    VERIFY(browsing_context.is_top_level());
+
+    // 1. Append browsingContext to group's browsing context set.
+    m_browsing_context_set.set(browsing_context);
+
+    // 2. Set browsingContext's group to group.
+    browsing_context.set_group(this);
+}
+
+}

Userland/Libraries/LibWeb/HTML/BrowsingContextGroup.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/HashMap.h>
+#include <AK/NonnullRefPtr.h>
+#include <AK/RefCounted.h>
+#include <LibWeb/Forward.h>
+
+namespace Web::HTML {
+
+class BrowsingContextGroup : public RefCounted<BrowsingContextGroup> {
+public:
+    static NonnullRefPtr<BrowsingContextGroup> create_a_new_browsing_context_group(Page&);
+    ~BrowsingContextGroup();
+
+    Page* page() { return m_page; }
+    Page const* page() const { return m_page; }
+
+    auto& browsing_context_set() { return m_browsing_context_set; }
+    auto const& browsing_context_set() const { return m_browsing_context_set; }
+
+    void append(BrowsingContext&);
+    void remove(BrowsingContext&);
+
+private:
+    explicit BrowsingContextGroup(Web::Page&);
+
+    // https://html.spec.whatwg.org/multipage/browsers.html#browsing-context-group-set
+    OrderedHashTable<NonnullRefPtr<BrowsingContext>> m_browsing_context_set;
+
+    WeakPtr<Page> m_page;
+};
+
+}

Userland/Libraries/LibWeb/Page/Page.cpp

@@ -13,7 +13,7 @@ namespace Web {
 Page::Page(PageClient& client)
     : m_client(client)
 {
-    m_top_level_browsing_context = HTML::BrowsingContext::create_a_new_browsing_context(*this, nullptr, nullptr);
+    m_top_level_browsing_context = HTML::BrowsingContext::create_a_new_top_level_browsing_context(*this);
 }
 
 Page::~Page() = default;