ladybird/Libraries/LibWeb/HTML/HTMLLinkElement.h
Andreas Kling 043e96946f LibWeb: Block rendering until linked stylesheets are loaded
This commit implements the main "render blocking" behavior for link
elements, drastically reducing the amount of FOUC (flash of unstyled
content) we subject our users to.

The document will now block rendering until linked style sheets
referenced by parser-created link elements have loaded (or failed).

Note that we don't yet extend the blocking period until "critical
subresources" such as imported style sheets have been downloaded
as well.
2025-02-27 21:36:40 +01:00

162 lines
6.4 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>);
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;
};
}