feat(ui): add UI crate timeline types for handling MSC3489 live location sharing

# Conflicts:
#	crates/matrix-sdk-ui/src/timeline/event_item/mod.rs
#	crates/matrix-sdk-ui/src/timeline/mod.rs

crates/matrix-sdk-ui/src/timeline/event_item/content/live_location.rs

@@ -0,0 +1,139 @@
+// Copyright 2026 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Timeline item content for live location sharing (MSC3489).
+//!
+//! Live location sharing uses two event types:
+//! - `org.matrix.msc3672.beacon_info` (state event): starts/stops a sharing
+//!   session and creates the timeline item represented by
+//!   [`LiveLocationState`].
+//! - `org.matrix.msc3672.beacon` (message-like event): periodic location
+//!   updates that are aggregated onto the parent [`LiveLocationState`] item.
+
+use ruma::{MilliSecondsSinceUnixEpoch, events::beacon_info::BeaconInfoEventContent};
+
+/// A single location update received from a beacon event.
+///
+/// Created from an `org.matrix.msc3672.beacon` message-like event and
+/// aggregated onto the parent [`LiveLocationState`] timeline item.
+#[derive(Clone, Debug)]
+pub struct BeaconInfo {
+    /// The geo URI carrying the user's coordinates (e.g.
+    /// `"geo:51.5008,0.1247;u=35"`).
+    pub(in crate::timeline) geo_uri: String,
+
+    /// Timestamp of this location update (from the beacon event's
+    /// `org.matrix.msc3488.ts` field).
+    pub(in crate::timeline) ts: MilliSecondsSinceUnixEpoch,
+
+    /// An optional human-readable description of the location.
+    pub(in crate::timeline) description: Option<String>,
+}
+
+impl BeaconInfo {
+    /// The geo URI of this location update.
+    pub fn geo_uri(&self) -> &str {
+        &self.geo_uri
+    }
+
+    /// The timestamp of this location update.
+    pub fn ts(&self) -> MilliSecondsSinceUnixEpoch {
+        self.ts
+    }
+
+    /// An optional human-readable description of this location.
+    pub fn description(&self) -> Option<&str> {
+        self.description.as_deref()
+    }
+}
+
+/// The state of a live location sharing session.
+///
+/// Created when a `org.matrix.msc3672.beacon_info` state event is received.
+/// Subsequent `org.matrix.msc3672.beacon` message-like events are aggregated
+/// onto this item, appending to [`LiveLocationState::locations`].
+///
+/// When a user stops sharing (a new `beacon_info` with `live: false` arrives)
+/// a *separate* timeline item is created for the stop event. The original
+/// item's liveness can be checked via [`LiveLocationState::is_live`], which
+/// internally checks both the `live` flag and the session timeout.
+#[derive(Clone, Debug)]
+pub struct LiveLocationState {
+    /// The content of the `beacon_info` state event that created this item.
+    pub(in crate::timeline) beacon_info: BeaconInfoEventContent,
+
+    /// All location updates aggregated onto this session, kept sorted by
+    /// timestamp.
+    pub(in crate::timeline) locations: Vec<BeaconInfo>,
+}
+
+impl LiveLocationState {
+    /// Create a new [`LiveLocationState`] from the given
+    /// [`BeaconInfoEventContent`].
+    pub fn new(beacon_info: BeaconInfoEventContent) -> Self {
+        Self { beacon_info, locations: Vec::new() }
+    }
+
+    /// Add a location update. Keeps the internal list sorted by timestamp so
+    /// that [`LiveLocationState::latest_location`] always returns the most
+    /// recent one.
+    pub(in crate::timeline) fn add_location(&mut self, location: BeaconInfo) {
+        match self.locations.binary_search_by_key(&location.ts, |l| l.ts) {
+            Ok(_) => return, // Duplicate timestamp, do nothing.
+            Err(index) => self.locations.insert(index, location),
+        }
+    }
+
+    /// Remove the location update with the given timestamp. Used when
+    /// unapplying an aggregation (e.g. event cache moves an event).
+    pub(in crate::timeline) fn remove_location(&mut self, ts: MilliSecondsSinceUnixEpoch) {
+        self.locations.retain(|l| l.ts != ts);
+    }
+
+    /// All accumulated location updates, sorted by timestamp (oldest first).
+    pub fn locations(&self) -> &[BeaconInfo] {
+        &self.locations
+    }
+
+    /// The most recent location update, if any have been received.
+    pub fn latest_location(&self) -> Option<&BeaconInfo> {
+        self.locations.last()
+    }
+
+    /// Whether this live location share is still active.
+    ///
+    /// Returns `false` once the `live` flag has been set to `false` **or**
+    /// the session's timeout has elapsed.
+    pub fn is_live(&self) -> bool {
+        self.beacon_info.is_live()
+    }
+
+    /// Update this session with a stop `beacon_info` event (one where
+    /// `live` is `false`). This replaces the stored content so that
+    /// [`LiveLocationState::is_live`] will return `false`.
+    pub(in crate::timeline) fn stop(&mut self, beacon_info: BeaconInfoEventContent) {
+        self.beacon_info = beacon_info;
+    }
+
+    /// An optional human-readable description for this sharing session
+    /// (from the originating `beacon_info` event).
+    pub fn description(&self) -> Option<&str> {
+        self.beacon_info.description.as_deref()
+    }
+
+    /// The full `beacon_info` event content that started this session.
+    pub fn beacon_info(&self) -> &BeaconInfoEventContent {
+        &self.beacon_info
+    }
+}

crates/matrix-sdk-ui/src/timeline/event_item/content/mod.rs

@@ -52,6 +52,7 @@ use ruma::{
     room_version_rules::RedactionRules,
 };
 
+mod live_location;
 mod message;
 mod msg_like;
 pub(super) mod other;
@@ -65,6 +66,7 @@ pub(in crate::timeline) use self::message::{
     extract_bundled_edit_event_json, extract_poll_edit_content, extract_room_msg_edit_content,
 };
 pub use self::{
+    live_location::{BeaconInfo, LiveLocationState},
     message::Message,
     msg_like::{MsgLikeContent, MsgLikeKind, ThreadSummary},
     other::OtherMessageLike,
@@ -114,6 +116,13 @@ pub enum TimelineItemContent {
 
     /// An `m.rtc.notification` event
     RtcNotification,
+
+    /// A live location sharing session (MSC3489).
+    ///
+    /// Created from an `org.matrix.msc3672.beacon_info` state event.
+    /// Subsequent `org.matrix.msc3672.beacon` message-like events are
+    /// aggregated onto this item.
+    LiveLocation(LiveLocationState),
 }
 
 impl TimelineItemContent {
@@ -121,6 +130,26 @@ impl TimelineItemContent {
         as_variant!(self, TimelineItemContent::MsgLike)
     }
 
+    /// If `self` is of the [`LiveLocation`][Self::LiveLocation] variant, return
+    /// the inner [`LiveLocationState`].
+    pub fn as_live_location_state(&self) -> Option<&LiveLocationState> {
+        as_variant!(self, Self::LiveLocation)
+    }
+
+    /// If `self` is of the [`LiveLocation`][Self::LiveLocation] variant, return
+    /// the inner [`LiveLocationState`] mutably.
+    pub(in crate::timeline) fn as_live_location_state_mut(
+        &mut self,
+    ) -> Option<&mut LiveLocationState> {
+        as_variant!(self, Self::LiveLocation)
+    }
+
+    /// Check whether this item's content is a live location
+    /// [`LiveLocation`][Self::LiveLocation].
+    pub fn is_live_location(&self) -> bool {
+        matches!(self, Self::LiveLocation(_))
+    }
+
     /// If `self` is of the [`MsgLike`][Self::MsgLike] variant, return the
     /// inner [`Message`].
     pub fn as_message(&self) -> Option<&Message> {
@@ -227,6 +256,7 @@ impl TimelineItemContent {
             | TimelineItemContent::FailedToParseState { .. } => "an event that couldn't be parsed",
             TimelineItemContent::CallInvite => "a call invite",
             TimelineItemContent::RtcNotification => "a call notification",
+            TimelineItemContent::LiveLocation(_) => "a live location share",
         }
     }
 
@@ -297,7 +327,7 @@ impl TimelineItemContent {
 
     pub(in crate::timeline) fn redact(&self, rules: &RedactionRules) -> Self {
         match self {
-            Self::MsgLike(_) | Self::CallInvite | Self::RtcNotification => {
+            Self::MsgLike(_) | Self::CallInvite | Self::RtcNotification | Self::LiveLocation(_) => {
                 TimelineItemContent::MsgLike(MsgLikeContent::redacted())
             }
             Self::MembershipChange(ev) => Self::MembershipChange(ev.redact(rules)),
@@ -329,7 +359,8 @@ impl TimelineItemContent {
             | TimelineItemContent::FailedToParseMessageLike { .. }
             | TimelineItemContent::FailedToParseState { .. }
             | TimelineItemContent::CallInvite
-            | TimelineItemContent::RtcNotification => {
+            | TimelineItemContent::RtcNotification
+            | TimelineItemContent::LiveLocation(..) => {
                 // No reactions for these kind of items.
                 None
             }
@@ -354,7 +385,8 @@ impl TimelineItemContent {
             | TimelineItemContent::FailedToParseMessageLike { .. }
             | TimelineItemContent::FailedToParseState { .. }
             | TimelineItemContent::CallInvite
-            | TimelineItemContent::RtcNotification => {
+            | TimelineItemContent::RtcNotification
+            | TimelineItemContent::LiveLocation(..) => {
                 // No reactions for these kind of items.
                 None
             }

crates/matrix-sdk-ui/src/timeline/event_item/mod.rs

@@ -40,10 +40,10 @@ mod remote;
 
 pub use self::{
     content::{
-        AnyOtherStateEventContentChange, EmbeddedEvent, EncryptedMessage, InReplyToDetails,
-        MemberProfileChange, MembershipChange, Message, MsgLikeContent, MsgLikeKind,
-        OtherMessageLike, OtherState, PollResult, PollState, RoomMembershipChange,
-        RoomPinnedEventsChange, Sticker, ThreadSummary, TimelineItemContent,
+        AnyOtherStateEventContentChange, BeaconInfo, EmbeddedEvent, EncryptedMessage,
+        InReplyToDetails, LiveLocationState, MemberProfileChange, MembershipChange, Message,
+        MsgLikeContent, MsgLikeKind, OtherMessageLike, OtherState, PollResult, PollState,
+        RoomMembershipChange, RoomPinnedEventsChange, Sticker, ThreadSummary, TimelineItemContent,
     },
     local::{EventSendState, MediaUploadProgress},
 };
@@ -562,7 +562,8 @@ impl EventTimelineItem {
             | TimelineItemContent::FailedToParseMessageLike { .. }
             | TimelineItemContent::FailedToParseState { .. }
             | TimelineItemContent::CallInvite
-            | TimelineItemContent::RtcNotification => None,
+            | TimelineItemContent::RtcNotification
+            | TimelineItemContent::LiveLocation(_) => None,
         };
 
         if let Some(body) = body {

crates/matrix-sdk-ui/src/timeline/mod.rs

@@ -88,12 +88,12 @@ pub use self::{
     error::*,
     event_filter::{TimelineEventCondition, TimelineEventFilter},
     event_item::{
-        AnyOtherStateEventContentChange, EmbeddedEvent, EncryptedMessage, EventItemOrigin,
-        EventSendState, EventTimelineItem, InReplyToDetails, MediaUploadProgress,
-        MemberProfileChange, MembershipChange, Message, MsgLikeContent, MsgLikeKind,
-        OtherMessageLike, OtherState, PollResult, PollState, Profile, ReactionInfo, ReactionStatus,
-        ReactionsByKeyBySender, RoomMembershipChange, RoomPinnedEventsChange, Sticker,
-        ThreadSummary, TimelineDetails, TimelineEventItemId, TimelineEventShieldState,
+        AnyOtherStateEventContentChange, BeaconInfo, EmbeddedEvent, EncryptedMessage,
+        EventItemOrigin, EventSendState, EventTimelineItem, InReplyToDetails, LiveLocationState,
+        MediaUploadProgress, MemberProfileChange, MembershipChange, Message, MsgLikeContent,
+        MsgLikeKind, OtherMessageLike, OtherState, PollResult, PollState, Profile, ReactionInfo,
+        ReactionStatus, ReactionsByKeyBySender, RoomMembershipChange, RoomPinnedEventsChange,
+        Sticker, ThreadSummary, TimelineDetails, TimelineEventItemId, TimelineEventShieldState,
         TimelineEventShieldStateCode, TimelineItemContent,
     },
     item::{TimelineItem, TimelineItemKind, TimelineUniqueId},