feat: add `Notification` Web API binding (#34842)

* feat: add Notification Web API binding

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: update spec link

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: fix clippy

Signed-off-by: Jason Tsai <git@pews.dev>

* fix: index overflow

Signed-off-by: Jason Tsai <git@pews.dev>

* test(tidy): add notification WebIDL standard URL

Signed-off-by: Jason Tsai <git@pews.dev>

* fix: allow crown::unrooted_must_root

Signed-off-by: Jason Tsai <git@pews.dev>

* implement GetPermission

Signed-off-by: Jason Tsai <git@pews.dev>

* fix silent type

Signed-off-by: Jason Tsai <git@pews.dev>

* add all properties

Signed-off-by: Jason Tsai <git@pews.dev>

* test: add Notification to global

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: update wpt manifest and fix clippy

Signed-off-by: Jason Tsai <git@pews.dev>

* test: temp skip notifications

Signed-off-by: Jason Tsai <git@pews.dev>

* add vibration and apply suggestions

Signed-off-by: Jason Tsai <git@pews.dev>

* partially implement RequestPermission

Signed-off-by: Jason Tsai <git@pews.dev>

* call Permission request permission algorithm

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: pub crate Notification

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: fix clippy

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: crown attribute

Signed-off-by: Jason Tsai <git@pews.dev>

* fix part of suggestions

Signed-off-by: Jason Tsai <git@pews.dev>

* fix: store private `Action` structure

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: fix typo

Signed-off-by: Jason Tsai <git@pews.dev>

* fix: serialize images URL

Signed-off-by: Jason Tsai <git@pews.dev>

* fix: use globalscope as environment settings object

Signed-off-by: Jason Tsai <git@pews.dev>

* chore: add pref `dom_notification_enabled` and default to disabled

Signed-off-by: Jason Tsai <git@pews.dev>

* fix: use `descriptor_permission_state`

Signed-off-by: Jason Tsai <git@pews.dev>

* apply suggestions

Signed-off-by: Jason Tsai <git@pews.dev>
Co-authored-by: Josh Matthews <josh@joshmatthews.net>

* test: remove passed meta

Signed-off-by: Jason Tsai <git@pews.dev>

* test: enable notification prefs in mozilla tests

Signed-off-by: Jason Tsai <git@pews.dev>

---------

Signed-off-by: Jason Tsai <git@pews.dev>
Co-authored-by: Josh Matthews <josh@joshmatthews.net>

1 files changed, 562 insertions, 0 deletions

diff --git a/components/script/dom/notification.rs b/components/script/dom/notification.rs
new file mode 100644
index 00000000000..49bbd4b74d6
--- /dev/null
+++ b/components/script/dom/notification.rs
@@ -0,0 +1,562 @@
+/* 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/. */
+
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use dom_struct::dom_struct;
+use js::jsapi::Heap;
+use js::jsval::JSVal;
+use js::rust::{HandleObject, MutableHandleValue};
+use servo_url::{ImmutableOrigin, ServoUrl};
+use uuid::Uuid;
+
+use super::bindings::refcounted::TrustedPromise;
+use super::bindings::reflector::DomGlobal;
+use super::permissionstatus::PermissionStatus;
+use crate::dom::bindings::callback::ExceptionHandling;
+use crate::dom::bindings::codegen::Bindings::NotificationBinding::{
+    NotificationAction, NotificationDirection, NotificationMethods, NotificationOptions,
+    NotificationPermission, NotificationPermissionCallback,
+};
+use crate::dom::bindings::codegen::Bindings::PermissionStatusBinding::PermissionStatus_Binding::PermissionStatusMethods;
+use crate::dom::bindings::codegen::Bindings::PermissionStatusBinding::{
+    PermissionDescriptor, PermissionName, PermissionState,
+};
+use crate::dom::bindings::codegen::UnionTypes::UnsignedLongOrUnsignedLongSequence;
+use crate::dom::bindings::error::Error;
+use crate::dom::bindings::import::module::{Fallible, Rc};
+use crate::dom::bindings::inheritance::Castable;
+use crate::dom::bindings::reflector::reflect_dom_object_with_proto;
+use crate::dom::bindings::root::{Dom, DomRoot};
+use crate::dom::bindings::str::{DOMString, USVString};
+use crate::dom::bindings::trace::RootedTraceableBox;
+use crate::dom::bindings::utils::to_frozen_array;
+use crate::dom::eventtarget::EventTarget;
+use crate::dom::globalscope::GlobalScope;
+use crate::dom::permissions::{descriptor_permission_state, PermissionAlgorithm, Permissions};
+use crate::dom::promise::Promise;
+use crate::dom::serviceworkerglobalscope::ServiceWorkerGlobalScope;
+use crate::dom::serviceworkerregistration::ServiceWorkerRegistration;
+use crate::script_runtime::{CanGc, JSContext as SafeJSContext};
+
+// TODO: Service Worker API (persistent notification)
+// https://notifications.spec.whatwg.org/#service-worker-api
+
+/// <https://notifications.spec.whatwg.org/#notifications>
+#[dom_struct]
+pub(crate) struct Notification {
+    eventtarget: EventTarget,
+    /// <https://notifications.spec.whatwg.org/#service-worker-registration>
+    serviceworker_registration: Option<Dom<ServiceWorkerRegistration>>,
+    /// <https://notifications.spec.whatwg.org/#concept-title>
+    title: DOMString,
+    /// <https://notifications.spec.whatwg.org/#body>
+    body: DOMString,
+    /// <https://notifications.spec.whatwg.org/#data>
+    #[ignore_malloc_size_of = "mozjs"]
+    data: Heap<JSVal>,
+    /// <https://notifications.spec.whatwg.org/#concept-direction>
+    dir: NotificationDirection,
+    /// <https://notifications.spec.whatwg.org/#image-url>
+    image: Option<USVString>,
+    /// <https://notifications.spec.whatwg.org/#icon-url>
+    icon: Option<USVString>,
+    /// <https://notifications.spec.whatwg.org/#badge-url>
+    badge: Option<USVString>,
+    /// <https://notifications.spec.whatwg.org/#concept-language>
+    lang: DOMString,
+    /// <https://notifications.spec.whatwg.org/#silent-preference-flag>
+    silent: Option<bool>,
+    /// <https://notifications.spec.whatwg.org/#tag>
+    tag: DOMString,
+    /// <https://notifications.spec.whatwg.org/#concept-origin>
+    #[no_trace] // ImmutableOrigin is not traceable
+    origin: ImmutableOrigin,
+    /// <https://notifications.spec.whatwg.org/#vibration-pattern>
+    vibration_pattern: Vec<u32>,
+    /// <https://notifications.spec.whatwg.org/#timestamp>
+    timestamp: u64,
+    /// <https://notifications.spec.whatwg.org/#renotify-preference-flag>
+    renotify: bool,
+    /// <https://notifications.spec.whatwg.org/#require-interaction-preference-flag>
+    require_interaction: bool,
+    /// <https://notifications.spec.whatwg.org/#actions>
+    actions: Vec<Action>,
+    // TODO: image resource, icon resource, and badge resource
+}
+
+impl Notification {
+    #[allow(clippy::too_many_arguments)]
+    pub(crate) fn new(
+        global: &GlobalScope,
+        title: DOMString,
+        options: RootedTraceableBox<NotificationOptions>,
+        origin: ImmutableOrigin,
+        base_url: ServoUrl,
+        fallback_timestamp: u64,
+        proto: Option<HandleObject>,
+        can_gc: CanGc,
+    ) -> DomRoot<Self> {
+        let notification = reflect_dom_object_with_proto(
+            Box::new(Notification::new_inherited(
+                global,
+                title,
+                &options,
+                origin,
+                base_url,
+                fallback_timestamp,
+            )),
+            global,
+            proto,
+            can_gc,
+        );
+
+        notification.data.set(options.data.get());
+
+        notification
+    }
+
+    /// partial implementation of <https://notifications.spec.whatwg.org/#create-a-notification>
+    fn new_inherited(
+        global: &GlobalScope,
+        title: DOMString,
+        options: &RootedTraceableBox<NotificationOptions>,
+        origin: ImmutableOrigin,
+        base_url: ServoUrl,
+        fallback_timestamp: u64,
+    ) -> Self {
+        // TODO: missing call to https://html.spec.whatwg.org/multipage/#structuredserializeforstorage
+        // may be find in `dom/bindings/structuredclone.rs`
+        let data = Heap::default();
+
+        let title = title.clone();
+        let dir = options.dir;
+        let lang = options.lang.clone();
+        let body = options.body.clone();
+        let tag = options.tag.clone();
+
+        // If options["image"] exists, then parse it using baseURL, and if that does not return failure,
+        // set notification’s image URL to the return value. (Otherwise notification’s image URL is not set.)
+        let image = options.image.as_ref().and_then(|image_url| {
+            ServoUrl::parse_with_base(Some(&base_url), image_url.as_ref())
+                .map(|url| USVString::from(url.to_string()))
+                .ok()
+        });
+        // If options["icon"] exists, then parse it using baseURL, and if that does not return failure,
+        // set notification’s icon URL to the return value. (Otherwise notification’s icon URL is not set.)
+        let icon = options.icon.as_ref().and_then(|icon_url| {
+            ServoUrl::parse_with_base(Some(&base_url), icon_url.as_ref())
+                .map(|url| USVString::from(url.to_string()))
+                .ok()
+        });
+        // If options["badge"] exists, then parse it using baseURL, and if that does not return failure,
+        // set notification’s badge URL to the return value. (Otherwise notification’s badge URL is not set.)
+        let badge = options.badge.as_ref().and_then(|badge_url| {
+            ServoUrl::parse_with_base(Some(&base_url), badge_url.as_ref())
+                .map(|url| USVString::from(url.to_string()))
+                .ok()
+        });
+        // If options["vibrate"] exists, then validate and normalize it and
+        // set notification’s vibration pattern to the return value.
+        let vibration_pattern = match &options.vibrate {
+            Some(pattern) => validate_and_normalize_vibration_pattern(pattern),
+            None => Vec::new(),
+        };
+        // If options["timestamp"] exists, then set notification’s timestamp to the value.
+        // Otherwise, set notification’s timestamp to fallbackTimestamp.
+        let timestamp = options.timestamp.unwrap_or(fallback_timestamp);
+        let renotify = options.renotify;
+        let silent = options.silent;
+        let require_interaction = options.requireInteraction;
+
+        // For each entry in options["actions"]
+        // up to the maximum number of actions supported (skip any excess entries):
+        let mut actions: Vec<Action> = Vec::new();
+        let max_actions = Notification::MaxActions(global);
+        for action in options.actions.iter().take(max_actions as usize) {
+            actions.push(Action {
+                name: action.action.clone(),
+                title: action.title.clone(),
+                // If entry["icon"] exists, then parse it using baseURL, and if that does not return failure
+                // set action’s icon URL to the return value. (Otherwise action’s icon URL remains null.)
+                icon_url: action.icon.as_ref().and_then(|icon_url| {
+                    ServoUrl::parse_with_base(Some(&base_url), icon_url.as_ref())
+                        .map(|url| USVString::from(url.to_string()))
+                        .ok()
+                }),
+            });
+        }
+
+        Self {
+            eventtarget: EventTarget::new_inherited(),
+            // A non-persistent notification is a notification whose service worker registration is null.
+            serviceworker_registration: None,
+            title,
+            body,
+            data,
+            dir,
+            image,
+            icon,
+            badge,
+            lang,
+            silent,
+            origin,
+            vibration_pattern,
+            timestamp,
+            renotify,
+            tag,
+            require_interaction,
+            actions,
+        }
+    }
+}
+
+impl NotificationMethods<crate::DomTypeHolder> for Notification {
+    /// <https://notifications.spec.whatwg.org/#constructors>
+    fn Constructor(
+        global: &GlobalScope,
+        proto: Option<HandleObject>,
+        can_gc: CanGc,
+        title: DOMString,
+        options: RootedTraceableBox<NotificationOptions>,
+    ) -> Fallible<DomRoot<Notification>> {
+        // step 1: Check global is a ServiceWorkerGlobalScope
+        if global.is::<ServiceWorkerGlobalScope>() {
+            return Err(Error::Type(
+                "Notification constructor cannot be used in service worker.".to_string(),
+            ));
+        }
+
+        // step 2: Check options.actions must be empty
+        if !options.actions.is_empty() {
+            return Err(Error::Type(
+                "Actions are only supported for persistent notifications.".to_string(),
+            ));
+        }
+
+        // step 3: Create a notification with a settings object
+        let notification =
+            create_notification_with_settings_object(global, title, options, proto, can_gc)?;
+
+        // TODO: Run step 5.1, 5.2 in parallel
+        // step 5.1: If the result of getting the notifications permission state is not "granted",
+        //           then queue a task to fire an event named error on this, and abort these steps.
+        let permission_state = get_notifications_permission_state(global);
+        if permission_state != NotificationPermission::Granted {
+            global
+                .task_manager()
+                .dom_manipulation_task_source()
+                .queue_simple_event(notification.upcast(), atom!("error"));
+            // TODO: abort steps
+        }
+        // TODO: step 5.2: Run the notification show steps for notification
+        // https://notifications.spec.whatwg.org/#notification-show-steps
+
+        Ok(notification)
+    }
+
+    /// <https://notifications.spec.whatwg.org/#dom-notification-permission>
+    fn GetPermission(global: &GlobalScope) -> Fallible<NotificationPermission> {
+        Ok(get_notifications_permission_state(global))
+    }
+
+    /// <https://notifications.spec.whatwg.org/#dom-notification-requestpermission>
+    fn RequestPermission(
+        global: &GlobalScope,
+        permission_callback: Option<Rc<NotificationPermissionCallback>>,
+        can_gc: CanGc,
+    ) -> Rc<Promise> {
+        // Step 2: Let promise be a new promise in this’s relevant Realm.
+        let promise = Promise::new(global, can_gc);
+
+        // TODO: Step 3: Run these steps in parallel:
+        // Step 3.1: Let permissionState be the result of requesting permission to use "notifications".
+        let notification_permission = request_notification_permission(global);
+
+        // Step 3.2: Queue a global task on the DOM manipulation task source given global to run these steps:
+        let trusted_promise = TrustedPromise::new(promise.clone());
+        let uuid = Uuid::new_v4().simple().to_string();
+        let uuid_ = uuid.clone();
+
+        if let Some(callback) = permission_callback {
+            global.add_notification_permission_request_callback(uuid.clone(), callback.clone());
+        }
+
+        global.task_manager().dom_manipulation_task_source().queue(
+            task!(request_permission: move || {
+                let promise = trusted_promise.root();
+                let global = promise.global();
+
+                // Step 3.2.1: If deprecatedCallback is given,
+                //             then invoke deprecatedCallback with « permissionState » and "report".
+                if let Some(callback) = global.remove_notification_permission_request_callback(uuid_) {
+                    let _ = callback.Call__(notification_permission, ExceptionHandling::Report);
+                }
+
+                // Step 3.2.2: Resolve promise with permissionState.
+                promise.resolve_native(&notification_permission);
+            }),
+        );
+
+        promise
+    }
+
+    // <https://notifications.spec.whatwg.org/#dom-notification-onclick>
+    event_handler!(click, GetOnclick, SetOnclick);
+    // <https://notifications.spec.whatwg.org/#dom-notification-onshow>
+    event_handler!(show, GetOnshow, SetOnshow);
+    // <https://notifications.spec.whatwg.org/#dom-notification-onerror>
+    event_handler!(error, GetOnerror, SetOnerror);
+    // <https://notifications.spec.whatwg.org/#dom-notification-onclose>
+    event_handler!(close, GetOnclose, SetOnclose);
+
+    /// <https://notifications.spec.whatwg.org/#maximum-number-of-actions>
+    fn MaxActions(_global: &GlobalScope) -> u32 {
+        // TODO: determine the maximum number of actions
+        2
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-title>
+    fn Title(&self) -> DOMString {
+        self.title.clone()
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-dir>
+    fn Dir(&self) -> NotificationDirection {
+        self.dir
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-lang>
+    fn Lang(&self) -> DOMString {
+        self.lang.clone()
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-body>
+    fn Body(&self) -> DOMString {
+        self.body.clone()
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-tag>
+    fn Tag(&self) -> DOMString {
+        self.tag.clone()
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-image>
+    fn Image(&self) -> USVString {
+        // step 1: If there is no this’s notification’s image URL, then return the empty string.
+        // step 2: Return this’s notification’s image URL, serialized.
+        self.image.clone().unwrap_or_default()
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-icon>
+    fn Icon(&self) -> USVString {
+        // step 1: If there is no this’s notification’s icon URL, then return the empty string.
+        // step 2: Return this’s notification’s icon URL, serialized.
+        self.icon.clone().unwrap_or_default()
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-badge>
+    fn Badge(&self) -> USVString {
+        // step 1: If there is no this’s notification’s badge URL, then return the empty string.
+        // step 2: Return this’s notification’s badge URL, serialized.
+        self.badge.clone().unwrap_or_default()
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-renotify>
+    fn Renotify(&self) -> bool {
+        self.renotify
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-silent>
+    fn GetSilent(&self) -> Option<bool> {
+        self.silent
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-requireinteraction>
+    fn RequireInteraction(&self) -> bool {
+        self.require_interaction
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-data>
+    fn Data(&self, _cx: SafeJSContext, mut retval: MutableHandleValue) {
+        retval.set(self.data.get());
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-actions>
+    fn Actions(&self, cx: SafeJSContext, retval: MutableHandleValue) {
+        // step 1: Let frozenActions be an empty list of type NotificationAction.
+        let mut frozen_actions: Vec<NotificationAction> = Vec::new();
+
+        // step 2: For each entry of this’s notification’s actions
+        for action in self.actions.iter() {
+            let action = NotificationAction {
+                action: action.name.clone(),
+                title: action.title.clone(),
+                // If entry’s icon URL is non-null,
+                // then set action["icon"] to entry’s icon URL, icon_url, serialized.
+                icon: action.icon_url.clone(),
+            };
+
+            // TODO: step 2.5: Call Object.freeze on action, to prevent accidental mutation by scripts.
+            // step 2.6: Append action to frozenActions.
+            frozen_actions.push(action);
+        }
+
+        // step 3: Return the result of create a frozen array from frozenActions.
+        to_frozen_array(frozen_actions.as_slice(), cx, retval);
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-vibrate>
+    fn Vibrate(&self, cx: SafeJSContext, retval: MutableHandleValue) {
+        to_frozen_array(self.vibration_pattern.as_slice(), cx, retval);
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-timestamp>
+    fn Timestamp(&self) -> u64 {
+        self.timestamp
+    }
+    /// <https://notifications.spec.whatwg.org/#dom-notification-close>
+    fn Close(&self) {
+        // TODO: If notification is a persistent notification and notification was closed by the end user
+        // then fire a service worker notification event named "notificationclose" given notification.
+
+        // If notification is a non-persistent notification
+        // then queue a task to fire an event named close on the Notification object representing notification.
+        self.global()
+            .task_manager()
+            .dom_manipulation_task_source()
+            .queue_simple_event(self.upcast(), atom!("close"));
+    }
+}
+
+/// <https://notifications.spec.whatwg.org/#actions>
+#[derive(JSTraceable, MallocSizeOf)]
+struct Action {
+    /// <https://notifications.spec.whatwg.org/#action-name>
+    name: DOMString,
+    /// <https://notifications.spec.whatwg.org/#action-title>
+    title: DOMString,
+    /// <https://notifications.spec.whatwg.org/#action-icon-url>
+    icon_url: Option<USVString>,
+    // TODO: icon_resource <https://notifications.spec.whatwg.org/#action-icon-resource>
+}
+
+/// <https://notifications.spec.whatwg.org/#create-a-notification-with-a-settings-object>
+fn create_notification_with_settings_object(
+    global: &GlobalScope,
+    title: DOMString,
+    options: RootedTraceableBox<NotificationOptions>,
+    proto: Option<HandleObject>,
+    can_gc: CanGc,
+) -> Fallible<DomRoot<Notification>> {
+    // step 1: Let origin be settings’s origin.
+    let origin = global.origin().immutable().clone();
+    // step 2: Let baseURL be settings’s API base URL.
+    let base_url = global.api_base_url();
+    // step 3: Let fallbackTimestamp be the number of milliseconds from
+    //         the Unix epoch to settings’s current wall time, rounded to the nearest integer.
+    let fallback_timestamp = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_millis() as u64;
+    // step 4: Return the result of creating a notification given title, options, origin,
+    //         baseURL, and fallbackTimestamp.
+    create_notification(
+        global,
+        title,
+        options,
+        origin,
+        base_url,
+        fallback_timestamp,
+        proto,
+        can_gc,
+    )
+}
+
+/// <https://notifications.spec.whatwg.org/#create-a-notification
+#[allow(clippy::too_many_arguments)]
+fn create_notification(
+    global: &GlobalScope,
+    title: DOMString,
+    options: RootedTraceableBox<NotificationOptions>,
+    origin: ImmutableOrigin,
+    base_url: ServoUrl,
+    fallback_timestamp: u64,
+    proto: Option<HandleObject>,
+    can_gc: CanGc,
+) -> Fallible<DomRoot<Notification>> {
+    // If options["silent"] is true and options["vibrate"] exists, then throw a TypeError.
+    if options.silent.is_some() && options.vibrate.is_some() {
+        return Err(Error::Type(
+            "Can't specify vibration patterns when setting notification to silent.".to_string(),
+        ));
+    }
+    // If options["renotify"] is true and options["tag"] is the empty string, then throw a TypeError.
+    if options.renotify && options.tag.is_empty() {
+        return Err(Error::Type(
+            "tag must be set to renotify as an existing notification.".to_string(),
+        ));
+    }
+
+    Ok(Notification::new(
+        global,
+        title,
+        options,
+        origin,
+        base_url,
+        fallback_timestamp,
+        proto,
+        can_gc,
+    ))
+}
+
+/// <https://w3c.github.io/vibration/#dfn-validate-and-normalize>
+fn validate_and_normalize_vibration_pattern(
+    pattern: &UnsignedLongOrUnsignedLongSequence,
+) -> Vec<u32> {
+    // Step 1: If pattern is a list, proceed to the next step. Otherwise run the following substeps:
+    let mut pattern: Vec<u32> = match pattern {
+        UnsignedLongOrUnsignedLongSequence::UnsignedLong(value) => {
+            // Step 1.1: Let list be an initially empty list, and add pattern to list.
+            // Step 1.2: Set pattern to list.
+            vec![*value]
+        },
+        UnsignedLongOrUnsignedLongSequence::UnsignedLongSequence(values) => values.clone(),
+    };
+
+    // Step 2: Let max length have the value 10.
+    // Step 3: If the length of pattern is greater than max length, truncate pattern,
+    //         leaving only the first max length entries.
+    pattern.truncate(10);
+
+    // If the length of the pattern is even and not zero then the last entry in the pattern will
+    // have no effect so an implementation can remove it from the pattern at this point.
+    if pattern.len() % 2 == 0 && !pattern.is_empty() {
+        pattern.pop();
+    }
+
+    // Step 4: Let max duration have the value 10000.
+    // Step 5: For each entry in pattern whose value is greater than max duration,
+    //         set the entry's value to max duration.
+    pattern.iter_mut().for_each(|entry| {
+        *entry = 10000.min(*entry);
+    });
+
+    // Step 6: Return pattern.
+    pattern
+}
+
+/// <https://notifications.spec.whatwg.org/#get-the-notifications-permission-state>
+fn get_notifications_permission_state(global: &GlobalScope) -> NotificationPermission {
+    let permission_state = descriptor_permission_state(PermissionName::Notifications, Some(global));
+    match permission_state {
+        PermissionState::Granted => NotificationPermission::Granted,
+        PermissionState::Denied => NotificationPermission::Denied,
+        PermissionState::Prompt => NotificationPermission::Default,
+    }
+}
+
+fn request_notification_permission(global: &GlobalScope) -> NotificationPermission {
+    let cx = GlobalScope::get_cx();
+    let promise = &Promise::new(global, CanGc::note());
+    let descriptor = PermissionDescriptor {
+        name: PermissionName::Notifications,
+    };
+    let status = PermissionStatus::new(global, &descriptor);
+
+    // The implementation of `request_notification_permission` seemed to be synchronous
+    Permissions::permission_request(cx, promise, &descriptor, &status);
+
+    match status.State() {
+        PermissionState::Granted => NotificationPermission::Granted,
+        PermissionState::Denied => NotificationPermission::Denied,
+        // Should only receive "Granted" or "Denied" from the permission request
+        PermissionState::Prompt => NotificationPermission::Default,
+    }
+}