components/shared/script/lib.rs - servo - Git at Google

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

 //! This module contains traits in script used generically in the rest of Servo.
 //! The traits are here instead of in script so that these modules won't have
 //! to depend on script.

 #![deny(missing_docs)]
 #![deny(unsafe_code)]

 use std::fmt;
 use std::sync::Arc;

 use background_hang_monitor_api::BackgroundHangMonitorRegister;
 use base::cross_process_instant::CrossProcessInstant;
 use base::generic_channel::{GenericReceiver, GenericSender};
 use base::id::{BrowsingContextId, HistoryStateId, PipelineId, PipelineNamespaceId, WebViewId};
 #[cfg(feature = "bluetooth")]
 use bluetooth_traits::BluetoothRequest;
 use canvas_traits::webgl::WebGLPipeline;
 use compositing_traits::CrossProcessCompositorApi;
 use constellation_traits::{
     LoadData, NavigationHistoryBehavior, ScriptToConstellationChan, StructuredSerializedData,
     WindowSizeType,
 };
 use crossbeam_channel::{RecvTimeoutError, Sender};
 use devtools_traits::ScriptToDevtoolsControlMsg;
 use embedder_traits::user_content_manager::UserContentManager;
 use embedder_traits::{
     CompositorHitTestResult, FocusSequenceNumber, InputEvent, JavaScriptEvaluationId,
     MediaSessionActionType, ScriptToEmbedderChan, Theme, ViewportDetails, WebDriverScriptCommand,
 };
 use euclid::{Rect, Scale, Size2D, UnknownUnit};
 use fnv::FnvHashMap;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use keyboard_types::Modifiers;
 use malloc_size_of_derive::MallocSizeOf;
 use media::WindowGLContext;
 use net_traits::ResourceThreads;
 use net_traits::image_cache::ImageCache;
 use net_traits::storage_thread::StorageType;
 use pixels::PixelFormat;
 use profile_traits::mem;
 use serde::{Deserialize, Serialize};
 use servo_config::prefs::PrefValue;
 use servo_url::{ImmutableOrigin, ServoUrl};
 use strum_macros::IntoStaticStr;
 use style_traits::{CSSPixel, SpeculativePainter};
 use stylo_atoms::Atom;
 #[cfg(feature = "webgpu")]
 use webgpu_traits::WebGPUMsg;
 use webrender_api::units::{DevicePixel, LayoutVector2D};
 use webrender_api::{ExternalScrollId, ImageKey};

 /// The initial data required to create a new layout attached to an existing script thread.
 #[derive(Debug, Deserialize, Serialize)]
 pub struct NewLayoutInfo {
     /// The ID of the parent pipeline and frame type, if any.
     /// If `None`, this is a root pipeline.
     pub parent_info: Option<PipelineId>,
     /// Id of the newly-created pipeline.
     pub new_pipeline_id: PipelineId,
     /// Id of the browsing context associated with this pipeline.
     pub browsing_context_id: BrowsingContextId,
     /// Id of the top-level browsing context associated with this pipeline.
     pub webview_id: WebViewId,
     /// Id of the opener, if any
     pub opener: Option<BrowsingContextId>,
     /// Network request data which will be initiated by the script thread.
     pub load_data: LoadData,
     /// Initial [`ViewportDetails`] for this layout.
     pub viewport_details: ViewportDetails,
     /// The [`Theme`] of the new layout.
     pub theme: Theme,
 }

 /// When a pipeline is closed, should its browsing context be discarded too?
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
 pub enum DiscardBrowsingContext {
     /// Discard the browsing context
     Yes,
     /// Don't discard the browsing context
     No,
 }

 /// Is a document fully active, active or inactive?
 /// A document is active if it is the current active document in its session history,
 /// it is fuly active if it is active and all of its ancestors are active,
 /// and it is inactive otherwise.
 ///
 /// * <https://html.spec.whatwg.org/multipage/#active-document>
 /// * <https://html.spec.whatwg.org/multipage/#fully-active>
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize)]
 pub enum DocumentActivity {
     /// An inactive document
     Inactive,
     /// An active but not fully active document
     Active,
     /// A fully active document
     FullyActive,
 }

 /// Type of recorded progressive web metric
 #[derive(Clone, Copy, Debug, Deserialize, Serialize)]
 pub enum ProgressiveWebMetricType {
     /// Time to first Paint
     FirstPaint,
     /// Time to first contentful paint
     FirstContentfulPaint,
     /// Time to interactive
     TimeToInteractive,
 }

 /// The reason why the pipeline id of an iframe is being updated.
 #[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize)]
 pub enum UpdatePipelineIdReason {
     /// The pipeline id is being updated due to a navigation.
     Navigation,
     /// The pipeline id is being updated due to a history traversal.
     Traversal,
 }

 /// Messages sent to the `ScriptThread` event loop from the `Constellation`, `Compositor`, and (for
 /// now) `Layout`.
 #[derive(Deserialize, IntoStaticStr, Serialize)]
 pub enum ScriptThreadMessage {
     /// Takes the associated window proxy out of "delaying-load-events-mode",
     /// used if a scheduled navigated was refused by the embedder.
     /// <https://html.spec.whatwg.org/multipage/#delaying-load-events-mode>
     StopDelayingLoadEventsMode(PipelineId),
     /// Gives a channel and ID to a layout, as well as the ID of that layout's parent
     AttachLayout(NewLayoutInfo),
     /// Window resized.  Sends a DOM event eventually, but first we combine events.
     Resize(PipelineId, ViewportDetails, WindowSizeType),
     /// Theme changed.
     ThemeChange(PipelineId, Theme),
     /// Notifies script that window has been resized but to not take immediate action.
     ResizeInactive(PipelineId, ViewportDetails),
     /// Window switched from fullscreen mode.
     ExitFullScreen(PipelineId),
     /// Notifies the script that the document associated with this pipeline should 'unload'.
     UnloadDocument(PipelineId),
     /// Notifies the script that a pipeline should be closed.
     ExitPipeline(WebViewId, PipelineId, DiscardBrowsingContext),
     /// Notifies the script that the whole thread should be closed.
     ExitScriptThread,
     /// Sends a DOM event.
     SendInputEvent(PipelineId, ConstellationInputEvent),
     /// Request that the given pipeline refresh the cursor by doing a hit test at the most
     /// recently hovered cursor position and resetting the cursor. This happens after a
     /// display list update is rendered.
     RefreshCursor(PipelineId),
     /// Notifies script of the viewport.
     Viewport(PipelineId, Rect<f32, UnknownUnit>),
     /// Requests that the script thread immediately send the constellation the title of a pipeline.
     GetTitle(PipelineId),
     /// Notifies script thread of a change to one of its document's activity
     SetDocumentActivity(PipelineId, DocumentActivity),
     /// Set whether to use less resources by running timers at a heavily limited rate.
     SetThrottled(PipelineId, bool),
     /// Notify the containing iframe (in PipelineId) that the nested browsing context (BrowsingContextId) is throttled.
     SetThrottledInContainingIframe(PipelineId, BrowsingContextId, bool),
     /// Notifies script thread that a url should be loaded in this iframe.
     /// PipelineId is for the parent, BrowsingContextId is for the nested browsing context
     NavigateIframe(
         PipelineId,
         BrowsingContextId,
         LoadData,
         NavigationHistoryBehavior,
     ),
     /// Post a message to a given window.
     PostMessage {
         /// The target of the message.
         target: PipelineId,
         /// The source of the message.
         source: PipelineId,
         /// The top level browsing context associated with the source pipeline.
         source_browsing_context: WebViewId,
         /// The expected origin of the target.
         target_origin: Option<ImmutableOrigin>,
         /// The source origin of the message.
         /// <https://html.spec.whatwg.org/multipage/#dom-messageevent-origin>
         source_origin: ImmutableOrigin,
         /// The data to be posted.
         data: Box<StructuredSerializedData>,
     },
     /// Updates the current pipeline ID of a given iframe.
     /// First PipelineId is for the parent, second is the new PipelineId for the frame.
     UpdatePipelineId(
         PipelineId,
         BrowsingContextId,
         WebViewId,
         PipelineId,
         UpdatePipelineIdReason,
     ),
     /// Updates the history state and url of a given pipeline.
     UpdateHistoryState(PipelineId, Option<HistoryStateId>, ServoUrl),
     /// Removes inaccesible history states.
     RemoveHistoryStates(PipelineId, Vec<HistoryStateId>),
     /// Set an iframe to be focused. Used when an element in an iframe gains focus.
     /// PipelineId is for the parent, BrowsingContextId is for the nested browsing context
     FocusIFrame(PipelineId, BrowsingContextId, FocusSequenceNumber),
     /// Focus the document. Used when the container gains focus.
     FocusDocument(PipelineId, FocusSequenceNumber),
     /// Notifies that the document's container (e.g., an iframe) is not included
     /// in the top-level browsing context's focus chain (not considering system
     /// focus) anymore.
     ///
     /// Obviously, this message is invalid for a top-level document.
     Unfocus(PipelineId, FocusSequenceNumber),
     /// Passes a webdriver command to the script thread for execution
     WebDriverScriptCommand(PipelineId, WebDriverScriptCommand),
     /// Notifies script thread that all animations are done
     TickAllAnimations(Vec<WebViewId>),
     /// Notifies the script thread that a new Web font has been loaded, and thus the page should be
     /// reflowed.
     WebFontLoaded(PipelineId, bool /* success */),
     /// Cause a `load` event to be dispatched at the appropriate iframe element.
     DispatchIFrameLoadEvent {
         /// The frame that has been marked as loaded.
         target: BrowsingContextId,
         /// The pipeline that contains a frame loading the target pipeline.
         parent: PipelineId,
         /// The pipeline that has completed loading.
         child: PipelineId,
     },
     /// Cause a `storage` event to be dispatched at the appropriate window.
     /// The strings are key, old value and new value.
     DispatchStorageEvent(
         PipelineId,
         StorageType,
         ServoUrl,
         Option<String>,
         Option<String>,
         Option<String>,
     ),
     /// Report an error from a CSS parser for the given pipeline
     ReportCSSError(PipelineId, String, u32, u32, String),
     /// Reload the given page.
     Reload(PipelineId),
     /// Notifies the script thread about a new recorded paint metric.
     PaintMetric(
         PipelineId,
         ProgressiveWebMetricType,
         CrossProcessInstant,
         bool, /* first_reflow */
     ),
     /// Notifies the media session about a user requested media session action.
     MediaSessionAction(PipelineId, MediaSessionActionType),
     /// Notifies script thread that WebGPU server has started
     #[cfg(feature = "webgpu")]
     SetWebGPUPort(IpcReceiver<WebGPUMsg>),
     /// The compositor scrolled and is updating the scroll states of the nodes in the given
     /// pipeline via the Constellation.
     SetScrollStates(PipelineId, FnvHashMap<ExternalScrollId, LayoutVector2D>),
     /// Evaluate the given JavaScript and return a result via a corresponding message
     /// to the Constellation.
     EvaluateJavaScript(PipelineId, JavaScriptEvaluationId, String),
     /// A new batch of keys for the image cache for the specific pipeline.
     SendImageKeysBatch(PipelineId, Vec<ImageKey>),
     /// Preferences were updated in the parent process.
     PreferencesUpdated(Vec<(String, PrefValue)>),
     /// Notify the `ScriptThread` that the Servo renderer is no longer waiting on
     /// asynchronous image uploads for the given `Pipeline`. These are mainly used
     /// by canvas to perform uploads while the display list is being built.
     NoLongerWaitingOnAsychronousImageUpdates(PipelineId),
 }

 impl fmt::Debug for ScriptThreadMessage {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         let variant_string: &'static str = self.into();
         write!(formatter, "ConstellationControlMsg::{variant_string}")
     }
 }

 /// Used to determine if a script has any pending asynchronous activity.
 #[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
 pub enum DocumentState {
     /// The document has been loaded and is idle.
     Idle,
     /// The document is either loading or waiting on an event.
     Pending,
 }

 /// Input events from the embedder that are sent via the `Constellation`` to the `ScriptThread`.
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct ConstellationInputEvent {
     /// The hit test result of this input event, if any.
     pub hit_test_result: Option<CompositorHitTestResult>,
     /// The pressed mouse button state of the constellation when this input
     /// event was triggered.
     pub pressed_mouse_buttons: u16,
     /// The currently active keyboard modifiers.
     pub active_keyboard_modifiers: Modifiers,
     /// The [`InputEvent`] itself.
     pub event: InputEvent,
 }

 /// Data needed to construct a script thread.
 ///
 /// NB: *DO NOT* add any Senders or Receivers here! pcwalton will have to rewrite your code if you
 /// do! Use IPC senders and receivers instead.
 pub struct InitialScriptState {
     /// The ID of the pipeline with which this script thread is associated.
     pub id: PipelineId,
     /// The subpage ID of this pipeline to create in its pipeline parent.
     /// If `None`, this is the root.
     pub parent_info: Option<PipelineId>,
     /// The ID of the browsing context this script is part of.
     pub browsing_context_id: BrowsingContextId,
     /// The ID of the top-level browsing context this script is part of.
     pub webview_id: WebViewId,
     /// The ID of the opener, if any.
     pub opener: Option<BrowsingContextId>,
     /// Loading into a Secure Context
     pub inherited_secure_context: Option<bool>,
     /// A channel with which messages can be sent to us (the script thread).
     pub constellation_sender: GenericSender<ScriptThreadMessage>,
     /// A port on which messages sent by the constellation to script can be received.
     pub constellation_receiver: GenericReceiver<ScriptThreadMessage>,
     /// A channel on which messages can be sent to the constellation from script.
     pub pipeline_to_constellation_sender: ScriptToConstellationChan,
     /// A channel which allows script to send messages directly to the Embedder
     /// This will pump the embedder event loop.
     pub pipeline_to_embedder_sender: ScriptToEmbedderChan,
     /// A handle to register script-(and associated layout-)threads for hang monitoring.
     pub background_hang_monitor_register: Box<dyn BackgroundHangMonitorRegister>,
     /// A channel to the resource manager thread.
     pub resource_threads: ResourceThreads,
     /// A channel to the bluetooth thread.
     #[cfg(feature = "bluetooth")]
     pub bluetooth_sender: IpcSender<BluetoothRequest>,
     /// The image cache for this script thread.
     pub image_cache: Arc<dyn ImageCache>,
     /// A channel to the time profiler thread.
     pub time_profiler_sender: profile_traits::time::ProfilerChan,
     /// A channel to the memory profiler thread.
     pub memory_profiler_sender: mem::ProfilerChan,
     /// A channel to the developer tools, if applicable.
     pub devtools_server_sender: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
     /// Initial [`ViewportDetails`] for the frame that is initiating this `ScriptThread`.
     pub viewport_details: ViewportDetails,
     /// Initial [`Theme`] for the frame that is initiating this `ScriptThread`.
     pub theme: Theme,
     /// The ID of the pipeline namespace for this script thread.
     pub pipeline_namespace_id: PipelineNamespaceId,
     /// A ping will be sent on this channel once the script thread shuts down.
     pub content_process_shutdown_sender: Sender<()>,
     /// A channel to the WebGL thread used in this pipeline.
     pub webgl_chan: Option<WebGLPipeline>,
     /// The XR device registry
     pub webxr_registry: Option<webxr_api::Registry>,
     /// Access to the compositor across a process boundary.
     pub compositor_api: CrossProcessCompositorApi,
     /// Application window's GL Context for Media player
     pub player_context: WindowGLContext,
     /// User content manager
     pub user_content_manager: UserContentManager,
     /// A list of URLs that can access privileged internal APIs.
     pub privileged_urls: Vec<ServoUrl>,
 }

 /// Errors from executing a paint worklet
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub enum PaintWorkletError {
     /// Execution timed out.
     Timeout,
     /// No such worklet.
     WorkletNotFound,
 }

 impl From<RecvTimeoutError> for PaintWorkletError {
     fn from(_: RecvTimeoutError) -> PaintWorkletError {
         PaintWorkletError::Timeout
     }
 }

 /// Execute paint code in the worklet thread pool.
 pub trait Painter: SpeculativePainter {
     /// <https://drafts.css-houdini.org/css-paint-api/#draw-a-paint-image>
     fn draw_a_paint_image(
         &self,
         size: Size2D<f32, CSSPixel>,
         zoom: Scale<f32, CSSPixel, DevicePixel>,
         properties: Vec<(Atom, String)>,
         arguments: Vec<String>,
     ) -> Result<DrawAPaintImageResult, PaintWorkletError>;
 }

 impl fmt::Debug for dyn Painter {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         fmt.debug_tuple("Painter")
             .field(&format_args!(".."))
             .finish()
     }
 }

 /// The result of executing paint code: the image together with any image URLs that need to be loaded.
 ///
 /// TODO: this should return a WR display list. <https://github.com/servo/servo/issues/17497>
 #[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
 pub struct DrawAPaintImageResult {
     /// The image height
     pub width: u32,
     /// The image width
     pub height: u32,
     /// The image format
     pub format: PixelFormat,
     /// The image drawn, or None if an invalid paint image was drawn
     pub image_key: Option<ImageKey>,
     /// Drawing the image might have requested loading some image URLs.
     pub missing_image_urls: Vec<ServoUrl>,
 }
	/* This Source Code Form is subject to the terms of the Mozilla Public
	* License, v. 2.0. If a copy of the MPL was not distributed with this
	* file, You can obtain one at https://mozilla.org/MPL/2.0/. */

	//! This module contains traits in script used generically in the rest of Servo.
	//! The traits are here instead of in script so that these modules won't have
	//! to depend on script.

	#![deny(missing_docs)]
	#![deny(unsafe_code)]

	use std::fmt;
	use std::sync::Arc;

	use background_hang_monitor_api::BackgroundHangMonitorRegister;
	use base::cross_process_instant::CrossProcessInstant;
	use base::generic_channel::{GenericReceiver, GenericSender};
	use base::id::{BrowsingContextId, HistoryStateId, PipelineId, PipelineNamespaceId, WebViewId};
	#[cfg(feature = "bluetooth")]
	use bluetooth_traits::BluetoothRequest;
	use canvas_traits::webgl::WebGLPipeline;
	use compositing_traits::CrossProcessCompositorApi;
	use constellation_traits::{
	LoadData, NavigationHistoryBehavior, ScriptToConstellationChan, StructuredSerializedData,
	WindowSizeType,
	};
	use crossbeam_channel::{RecvTimeoutError, Sender};
	use devtools_traits::ScriptToDevtoolsControlMsg;
	use embedder_traits::user_content_manager::UserContentManager;
	use embedder_traits::{
	CompositorHitTestResult, FocusSequenceNumber, InputEvent, JavaScriptEvaluationId,
	MediaSessionActionType, ScriptToEmbedderChan, Theme, ViewportDetails, WebDriverScriptCommand,
	};
	use euclid::{Rect, Scale, Size2D, UnknownUnit};
	use fnv::FnvHashMap;
	use ipc_channel::ipc::{IpcReceiver, IpcSender};
	use keyboard_types::Modifiers;
	use malloc_size_of_derive::MallocSizeOf;
	use media::WindowGLContext;
	use net_traits::ResourceThreads;
	use net_traits::image_cache::ImageCache;
	use net_traits::storage_thread::StorageType;
	use pixels::PixelFormat;
	use profile_traits::mem;
	use serde::{Deserialize, Serialize};
	use servo_config::prefs::PrefValue;
	use servo_url::{ImmutableOrigin, ServoUrl};
	use strum_macros::IntoStaticStr;
	use style_traits::{CSSPixel, SpeculativePainter};
	use stylo_atoms::Atom;
	#[cfg(feature = "webgpu")]
	use webgpu_traits::WebGPUMsg;
	use webrender_api::units::{DevicePixel, LayoutVector2D};
	use webrender_api::{ExternalScrollId, ImageKey};

	/// The initial data required to create a new layout attached to an existing script thread.
	#[derive(Debug, Deserialize, Serialize)]
	pub struct NewLayoutInfo {
	/// The ID of the parent pipeline and frame type, if any.
	/// If `None`, this is a root pipeline.
	pub parent_info: Option<PipelineId>,
	/// Id of the newly-created pipeline.
	pub new_pipeline_id: PipelineId,
	/// Id of the browsing context associated with this pipeline.
	pub browsing_context_id: BrowsingContextId,
	/// Id of the top-level browsing context associated with this pipeline.
	pub webview_id: WebViewId,
	/// Id of the opener, if any
	pub opener: Option<BrowsingContextId>,
	/// Network request data which will be initiated by the script thread.
	pub load_data: LoadData,
	/// Initial [`ViewportDetails`] for this layout.
	pub viewport_details: ViewportDetails,
	/// The [`Theme`] of the new layout.
	pub theme: Theme,
	}

	/// When a pipeline is closed, should its browsing context be discarded too?
	#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, PartialEq, Serialize)]
	pub enum DiscardBrowsingContext {
	/// Discard the browsing context
	Yes,
	/// Don't discard the browsing context
	No,
	}

	/// Is a document fully active, active or inactive?
	/// A document is active if it is the current active document in its session history,
	/// it is fuly active if it is active and all of its ancestors are active,
	/// and it is inactive otherwise.
	///
	/// * <https://html.spec.whatwg.org/multipage/#active-document>
	/// * <https://html.spec.whatwg.org/multipage/#fully-active>
	#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize)]
	pub enum DocumentActivity {
	/// An inactive document
	Inactive,
	/// An active but not fully active document
	Active,
	/// A fully active document
	FullyActive,
	}

	/// Type of recorded progressive web metric
	#[derive(Clone, Copy, Debug, Deserialize, Serialize)]
	pub enum ProgressiveWebMetricType {
	/// Time to first Paint
	FirstPaint,
	/// Time to first contentful paint
	FirstContentfulPaint,
	/// Time to interactive
	TimeToInteractive,
	}

	/// The reason why the pipeline id of an iframe is being updated.
	#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize)]
	pub enum UpdatePipelineIdReason {
	/// The pipeline id is being updated due to a navigation.
	Navigation,
	/// The pipeline id is being updated due to a history traversal.
	Traversal,
	}

	/// Messages sent to the `ScriptThread` event loop from the `Constellation`, `Compositor`, and (for
	/// now) `Layout`.
	#[derive(Deserialize, IntoStaticStr, Serialize)]
	pub enum ScriptThreadMessage {
	/// Takes the associated window proxy out of "delaying-load-events-mode",
	/// used if a scheduled navigated was refused by the embedder.
	/// <https://html.spec.whatwg.org/multipage/#delaying-load-events-mode>
	StopDelayingLoadEventsMode(PipelineId),
	/// Gives a channel and ID to a layout, as well as the ID of that layout's parent
	AttachLayout(NewLayoutInfo),
	/// Window resized. Sends a DOM event eventually, but first we combine events.
	Resize(PipelineId, ViewportDetails, WindowSizeType),
	/// Theme changed.
	ThemeChange(PipelineId, Theme),
	/// Notifies script that window has been resized but to not take immediate action.
	ResizeInactive(PipelineId, ViewportDetails),
	/// Window switched from fullscreen mode.
	ExitFullScreen(PipelineId),
	/// Notifies the script that the document associated with this pipeline should 'unload'.
	UnloadDocument(PipelineId),
	/// Notifies the script that a pipeline should be closed.
	ExitPipeline(WebViewId, PipelineId, DiscardBrowsingContext),
	/// Notifies the script that the whole thread should be closed.
	ExitScriptThread,
	/// Sends a DOM event.
	SendInputEvent(PipelineId, ConstellationInputEvent),
	/// Request that the given pipeline refresh the cursor by doing a hit test at the most
	/// recently hovered cursor position and resetting the cursor. This happens after a
	/// display list update is rendered.
	RefreshCursor(PipelineId),
	/// Notifies script of the viewport.
	Viewport(PipelineId, Rect<f32, UnknownUnit>),
	/// Requests that the script thread immediately send the constellation the title of a pipeline.
	GetTitle(PipelineId),
	/// Notifies script thread of a change to one of its document's activity
	SetDocumentActivity(PipelineId, DocumentActivity),
	/// Set whether to use less resources by running timers at a heavily limited rate.
	SetThrottled(PipelineId, bool),
	/// Notify the containing iframe (in PipelineId) that the nested browsing context (BrowsingContextId) is throttled.
	SetThrottledInContainingIframe(PipelineId, BrowsingContextId, bool),
	/// Notifies script thread that a url should be loaded in this iframe.
	/// PipelineId is for the parent, BrowsingContextId is for the nested browsing context
	NavigateIframe(
	PipelineId,
	BrowsingContextId,
	LoadData,
	NavigationHistoryBehavior,
	),
	/// Post a message to a given window.
	PostMessage {
	/// The target of the message.
	target: PipelineId,
	/// The source of the message.
	source: PipelineId,
	/// The top level browsing context associated with the source pipeline.
	source_browsing_context: WebViewId,
	/// The expected origin of the target.
	target_origin: Option<ImmutableOrigin>,
	/// The source origin of the message.
	/// <https://html.spec.whatwg.org/multipage/#dom-messageevent-origin>
	source_origin: ImmutableOrigin,
	/// The data to be posted.
	data: Box<StructuredSerializedData>,
	},
	/// Updates the current pipeline ID of a given iframe.
	/// First PipelineId is for the parent, second is the new PipelineId for the frame.
	UpdatePipelineId(
	PipelineId,
	BrowsingContextId,
	WebViewId,
	PipelineId,
	UpdatePipelineIdReason,
	),
	/// Updates the history state and url of a given pipeline.
	UpdateHistoryState(PipelineId, Option<HistoryStateId>, ServoUrl),
	/// Removes inaccesible history states.
	RemoveHistoryStates(PipelineId, Vec<HistoryStateId>),
	/// Set an iframe to be focused. Used when an element in an iframe gains focus.
	/// PipelineId is for the parent, BrowsingContextId is for the nested browsing context
	FocusIFrame(PipelineId, BrowsingContextId, FocusSequenceNumber),
	/// Focus the document. Used when the container gains focus.
	FocusDocument(PipelineId, FocusSequenceNumber),
	/// Notifies that the document's container (e.g., an iframe) is not included
	/// in the top-level browsing context's focus chain (not considering system
	/// focus) anymore.
	///
	/// Obviously, this message is invalid for a top-level document.
	Unfocus(PipelineId, FocusSequenceNumber),
	/// Passes a webdriver command to the script thread for execution
	WebDriverScriptCommand(PipelineId, WebDriverScriptCommand),
	/// Notifies script thread that all animations are done
	TickAllAnimations(Vec<WebViewId>),
	/// Notifies the script thread that a new Web font has been loaded, and thus the page should be
	/// reflowed.
	WebFontLoaded(PipelineId, bool /* success */),
	/// Cause a `load` event to be dispatched at the appropriate iframe element.
	DispatchIFrameLoadEvent {
	/// The frame that has been marked as loaded.
	target: BrowsingContextId,
	/// The pipeline that contains a frame loading the target pipeline.
	parent: PipelineId,
	/// The pipeline that has completed loading.
	child: PipelineId,
	},
	/// Cause a `storage` event to be dispatched at the appropriate window.
	/// The strings are key, old value and new value.
	DispatchStorageEvent(
	PipelineId,
	StorageType,
	ServoUrl,
	Option<String>,
	Option<String>,
	Option<String>,
	),
	/// Report an error from a CSS parser for the given pipeline
	ReportCSSError(PipelineId, String, u32, u32, String),
	/// Reload the given page.
	Reload(PipelineId),
	/// Notifies the script thread about a new recorded paint metric.
	PaintMetric(
	PipelineId,
	ProgressiveWebMetricType,
	CrossProcessInstant,
	bool, /* first_reflow */
	),
	/// Notifies the media session about a user requested media session action.
	MediaSessionAction(PipelineId, MediaSessionActionType),
	/// Notifies script thread that WebGPU server has started
	#[cfg(feature = "webgpu")]
	SetWebGPUPort(IpcReceiver<WebGPUMsg>),
	/// The compositor scrolled and is updating the scroll states of the nodes in the given
	/// pipeline via the Constellation.
	SetScrollStates(PipelineId, FnvHashMap<ExternalScrollId, LayoutVector2D>),
	/// Evaluate the given JavaScript and return a result via a corresponding message
	/// to the Constellation.
	EvaluateJavaScript(PipelineId, JavaScriptEvaluationId, String),
	/// A new batch of keys for the image cache for the specific pipeline.
	SendImageKeysBatch(PipelineId, Vec<ImageKey>),
	/// Preferences were updated in the parent process.
	PreferencesUpdated(Vec<(String, PrefValue)>),
	/// Notify the `ScriptThread` that the Servo renderer is no longer waiting on
	/// asynchronous image uploads for the given `Pipeline`. These are mainly used
	/// by canvas to perform uploads while the display list is being built.
	NoLongerWaitingOnAsychronousImageUpdates(PipelineId),
	}

	impl fmt::Debug for ScriptThreadMessage {
	fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
	let variant_string: &'static str = self.into();
	write!(formatter, "ConstellationControlMsg::{variant_string}")
	}
	}

	/// Used to determine if a script has any pending asynchronous activity.
	#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Serialize)]
	pub enum DocumentState {
	/// The document has been loaded and is idle.
	Idle,
	/// The document is either loading or waiting on an event.
	Pending,
	}

	/// Input events from the embedder that are sent via the `Constellation`` to the `ScriptThread`.
	#[derive(Clone, Debug, Deserialize, Serialize)]
	pub struct ConstellationInputEvent {
	/// The hit test result of this input event, if any.
	pub hit_test_result: Option<CompositorHitTestResult>,
	/// The pressed mouse button state of the constellation when this input
	/// event was triggered.
	pub pressed_mouse_buttons: u16,
	/// The currently active keyboard modifiers.
	pub active_keyboard_modifiers: Modifiers,
	/// The [`InputEvent`] itself.
	pub event: InputEvent,
	}

	/// Data needed to construct a script thread.
	///
	/// NB: DO NOT add any Senders or Receivers here! pcwalton will have to rewrite your code if you
	/// do! Use IPC senders and receivers instead.
	pub struct InitialScriptState {
	/// The ID of the pipeline with which this script thread is associated.
	pub id: PipelineId,
	/// The subpage ID of this pipeline to create in its pipeline parent.
	/// If `None`, this is the root.
	pub parent_info: Option<PipelineId>,
	/// The ID of the browsing context this script is part of.
	pub browsing_context_id: BrowsingContextId,
	/// The ID of the top-level browsing context this script is part of.
	pub webview_id: WebViewId,
	/// The ID of the opener, if any.
	pub opener: Option<BrowsingContextId>,
	/// Loading into a Secure Context
	pub inherited_secure_context: Option<bool>,
	/// A channel with which messages can be sent to us (the script thread).
	pub constellation_sender: GenericSender<ScriptThreadMessage>,
	/// A port on which messages sent by the constellation to script can be received.
	pub constellation_receiver: GenericReceiver<ScriptThreadMessage>,
	/// A channel on which messages can be sent to the constellation from script.
	pub pipeline_to_constellation_sender: ScriptToConstellationChan,
	/// A channel which allows script to send messages directly to the Embedder
	/// This will pump the embedder event loop.
	pub pipeline_to_embedder_sender: ScriptToEmbedderChan,
	/// A handle to register script-(and associated layout-)threads for hang monitoring.
	pub background_hang_monitor_register: Box<dyn BackgroundHangMonitorRegister>,
	/// A channel to the resource manager thread.
	pub resource_threads: ResourceThreads,
	/// A channel to the bluetooth thread.
	#[cfg(feature = "bluetooth")]
	pub bluetooth_sender: IpcSender<BluetoothRequest>,
	/// The image cache for this script thread.
	pub image_cache: Arc<dyn ImageCache>,
	/// A channel to the time profiler thread.
	pub time_profiler_sender: profile_traits::time::ProfilerChan,
	/// A channel to the memory profiler thread.
	pub memory_profiler_sender: mem::ProfilerChan,
	/// A channel to the developer tools, if applicable.
	pub devtools_server_sender: Option<IpcSender<ScriptToDevtoolsControlMsg>>,
	/// Initial [`ViewportDetails`] for the frame that is initiating this `ScriptThread`.
	pub viewport_details: ViewportDetails,
	/// Initial [`Theme`] for the frame that is initiating this `ScriptThread`.
	pub theme: Theme,
	/// The ID of the pipeline namespace for this script thread.
	pub pipeline_namespace_id: PipelineNamespaceId,
	/// A ping will be sent on this channel once the script thread shuts down.
	pub content_process_shutdown_sender: Sender<()>,
	/// A channel to the WebGL thread used in this pipeline.
	pub webgl_chan: Option<WebGLPipeline>,
	/// The XR device registry
	pub webxr_registry: Option<webxr_api::Registry>,
	/// Access to the compositor across a process boundary.
	pub compositor_api: CrossProcessCompositorApi,
	/// Application window's GL Context for Media player
	pub player_context: WindowGLContext,
	/// User content manager
	pub user_content_manager: UserContentManager,
	/// A list of URLs that can access privileged internal APIs.
	pub privileged_urls: Vec<ServoUrl>,
	}

	/// Errors from executing a paint worklet
	#[derive(Clone, Debug, Deserialize, Serialize)]
	pub enum PaintWorkletError {
	/// Execution timed out.
	Timeout,
	/// No such worklet.
	WorkletNotFound,
	}

	impl From<RecvTimeoutError> for PaintWorkletError {
	fn from(_: RecvTimeoutError) -> PaintWorkletError {
	PaintWorkletError::Timeout
	}
	}

	/// Execute paint code in the worklet thread pool.
	pub trait Painter: SpeculativePainter {
	/// <https://drafts.css-houdini.org/css-paint-api/#draw-a-paint-image>
	fn draw_a_paint_image(
	&self,
	size: Size2D<f32, CSSPixel>,
	zoom: Scale<f32, CSSPixel, DevicePixel>,
	properties: Vec<(Atom, String)>,
	arguments: Vec<String>,
	) -> Result<DrawAPaintImageResult, PaintWorkletError>;
	}

	impl fmt::Debug for dyn Painter {
	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
	fmt.debug_tuple("Painter")
	.field(&format_args!(".."))
	.finish()
	}
	}

	/// The result of executing paint code: the image together with any image URLs that need to be loaded.
	///
	/// TODO: this should return a WR display list. <https://github.com/servo/servo/issues/17497>
	#[derive(Clone, Debug, Deserialize, MallocSizeOf, Serialize)]
	pub struct DrawAPaintImageResult {
	/// The image height
	pub width: u32,
	/// The image width
	pub height: u32,
	/// The image format
	pub format: PixelFormat,
	/// The image drawn, or None if an invalid paint image was drawn
	pub image_key: Option<ImageKey>,
	/// Drawing the image might have requested loading some image URLs.
	pub missing_image_urls: Vec<ServoUrl>,
	}