ladybird/Libraries/LibWeb/HTML/HTMLLinkElement.h
Andreas Kling 0c0650e60a LibWeb: Implement more of the "script-blocking style sheet" mechanism
The basic idea is that style sheets can block script execution under
some circumstances. With this commit, we now handle the simplest cases
where a parser-inserted link element gets to download its style sheet
before script execution continues.

This improves performance on Speedometer 3 where JavaScript APIs that
depend on layout results (like Element.scrollIntoView()) would get
called too early (before the relevant CSS was downloaded), and so we'd
perform premature layout work. This work then had to be redone after
downloading the CSS anyway, wasting time.

Note that our Text/input/link-re-enable-crash.html test had to be
tweaked after these changes, since it relied on the old, incorrect,
behavior where scripts would run before downloading CSS.
2025-04-20 14:54:21 +02:00

169 lines
6.6 KiB
C++

/*
* Copyright (c) 2018-2025, Andreas Kling <andreas@ladybird.org>
* Copyright (c) 2021, the SerenityOS developers.
* Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2023, Srikavin Ramkumar <me@srikavin.me>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibWeb/DOM/DocumentLoadEventDelayer.h>
#include <LibWeb/Fetch/Infrastructure/FetchAlgorithms.h>
#include <LibWeb/Fetch/Infrastructure/HTTP/Requests.h>
#include <LibWeb/HTML/CORSSettingAttribute.h>
#include <LibWeb/HTML/HTMLElement.h>
#include <LibWeb/Loader/Resource.h>
namespace Web::HTML {
class HTMLLinkElement final
: public HTMLElement
, public ResourceClient {
WEB_PLATFORM_OBJECT(HTMLLinkElement, HTMLElement);
GC_DECLARE_ALLOCATOR(HTMLLinkElement);
public:
virtual ~HTMLLinkElement() override;
virtual void inserted() override;
virtual void removed_from(Node* old_parent, Node& old_root) override;
String rel() const { return get_attribute_value(HTML::AttributeNames::rel); }
String type() const { return get_attribute_value(HTML::AttributeNames::type); }
String href() const { return get_attribute_value(HTML::AttributeNames::href); }
WebIDL::ExceptionOr<void> set_as(String const&);
GC::Ref<DOM::DOMTokenList> rel_list();
GC::Ref<DOM::DOMTokenList> sizes();
bool has_loaded_icon() const;
bool load_favicon_and_use_if_window_is_active();
static WebIDL::ExceptionOr<void> load_fallback_favicon_if_needed(GC::Ref<DOM::Document>);
void set_parser_document(Badge<HTMLParser>, GC::Ref<DOM::Document>);
void set_media(String);
String media() const;
GC::Ptr<CSS::CSSStyleSheet> sheet() const;
virtual bool contributes_a_script_blocking_style_sheet() const final;
private:
HTMLLinkElement(DOM::Document&, DOM::QualifiedName);
virtual void initialize(JS::Realm&) override;
virtual void attribute_changed(FlyString const& name, Optional<String> const& old_value, Optional<String> const& value, Optional<FlyString> const& namespace_) override;
// ^ResourceClient
virtual void resource_did_fail() override;
virtual void resource_did_load() override;
// ^DOM::Node
virtual bool is_html_link_element() const override { return true; }
// ^HTMLElement
virtual void visit_edges(Cell::Visitor&) override;
virtual bool is_implicitly_potentially_render_blocking() const override;
struct LinkProcessingOptions {
// href (default the empty string)
String href {};
// destination (default the empty string)
Optional<Fetch::Infrastructure::Request::Destination> destination {};
// initiator (default "link")
Optional<Fetch::Infrastructure::Request::InitiatorType> initiator { Fetch::Infrastructure::Request::InitiatorType::Link };
// integrity (default the empty string)
String integrity {};
// type (default the empty string)
String type {};
// cryptographic nonce metadata (default the empty string)
// A string
String cryptographic_nonce_metadata {};
// crossorigin (default No CORS)
// A CORS settings attribute state
CORSSettingAttribute crossorigin { CORSSettingAttribute::NoCORS };
// referrer policy (default the empty string)
// A referrer policy
ReferrerPolicy::ReferrerPolicy referrer_policy { ReferrerPolicy::ReferrerPolicy::EmptyString };
// FIXME: source set (default null)
// Null or a source set
// base URL
// A URL
URL::URL base_url;
// origin
// An origin
URL::Origin origin;
// environment
// An environment
GC::Ptr<HTML::EnvironmentSettingsObject> environment;
// policy container
// A policy container
GC::Ptr<HTML::PolicyContainer> policy_container;
// document (default null)
// Null or a Document
GC::Ptr<Web::DOM::Document> document;
// FIXME: on document ready (default null)
// Null or an algorithm accepting a Document
// fetch priority (default auto)
// A fetch priority attribute state
Fetch::Infrastructure::Request::Priority fetch_priority { Fetch::Infrastructure::Request::Priority::Auto };
};
// https://html.spec.whatwg.org/multipage/semantics.html#create-link-options-from-element
LinkProcessingOptions create_link_options();
// https://html.spec.whatwg.org/multipage/semantics.html#create-a-link-request
GC::Ptr<Fetch::Infrastructure::Request> create_link_request(LinkProcessingOptions const&);
// https://html.spec.whatwg.org/multipage/semantics.html#linked-resource-fetch-setup-steps
bool linked_resource_fetch_setup_steps(Fetch::Infrastructure::Request&);
// https://html.spec.whatwg.org/multipage/links.html#link-type-stylesheet:linked-resource-fetch-setup-steps
bool stylesheet_linked_resource_fetch_setup_steps(Fetch::Infrastructure::Request&);
// https://html.spec.whatwg.org/multipage/semantics.html#fetch-and-process-the-linked-resource
void fetch_and_process_linked_resource();
// https://html.spec.whatwg.org/multipage/semantics.html#process-the-linked-resource
void process_linked_resource(bool success, Fetch::Infrastructure::Response const&, Variant<Empty, Fetch::Infrastructure::FetchAlgorithms::ConsumeBodyFailureTag, ByteBuffer>);
// https://html.spec.whatwg.org/multipage/links.html#link-type-stylesheet:process-the-linked-resource
void process_stylesheet_resource(bool success, Fetch::Infrastructure::Response const&, Variant<Empty, Fetch::Infrastructure::FetchAlgorithms::ConsumeBodyFailureTag, ByteBuffer>);
// https://html.spec.whatwg.org/multipage/semantics.html#default-fetch-and-process-the-linked-resource
void default_fetch_and_process_linked_resource();
void resource_did_load_favicon();
struct Relationship {
enum {
Alternate = 1 << 0,
Stylesheet = 1 << 1,
Preload = 1 << 2,
DNSPrefetch = 1 << 3,
Preconnect = 1 << 4,
Icon = 1 << 5,
};
};
GC::Ptr<Fetch::Infrastructure::FetchController> m_fetch_controller;
GC::Ptr<CSS::CSSStyleSheet> m_loaded_style_sheet;
Optional<DOM::DocumentLoadEventDelayer> m_document_load_event_delayer;
GC::Ptr<DOM::DOMTokenList> m_rel_list;
GC::Ptr<DOM::DOMTokenList> m_sizes;
unsigned m_relationship { 0 };
// https://html.spec.whatwg.org/multipage/semantics.html#explicitly-enabled
bool m_explicitly_enabled { false };
Optional<String> m_mime_type;
WeakPtr<DOM::Document> m_parser_document;
};
}