ffi: allow creating a new detached timeline from a room

Author: bnjbvr

bindings/matrix-sdk-ffi/src/room.rs

@@ -2,10 +2,11 @@ use std::sync::Arc;
 
 use anyhow::{Context, Result};
 use matrix_sdk::{
+    event_cache::paginator::PaginatorError,
     room::{power_levels::RoomPowerLevelChanges, Room as SdkRoom, RoomMemberRole},
     RoomMemberships, RoomState,
 };
-use matrix_sdk_ui::timeline::RoomExt;
+use matrix_sdk_ui::timeline::{PaginationError, RoomExt, TimelineFocus};
 use mime::Mime;
 use ruma::{
     api::client::room::report_content,
@@ -30,7 +31,7 @@ use crate::{
     room_info::RoomInfo,
     room_member::RoomMember,
     ruma::ImageInfo,
-    timeline::{EventTimelineItem, ReceiptType, Timeline},
+    timeline::{EventTimelineItem, FocusEventError, ReceiptType, Timeline},
     utils::u64_to_uint,
     TaskHandle,
 };
@@ -167,6 +168,40 @@ impl Room {
         }
     }
 
+    /// Returns a timeline focused on the given event.
+    ///
+    /// Note: this timeline is independent from that returned with
+    /// [`Self::timeline`], and as such it is not cached.
+    pub async fn timeline_focused_on_event(
+        &self,
+        event_id: String,
+    ) -> Result<Arc<Timeline>, FocusEventError> {
+        let parsed_event_id = EventId::parse(&event_id).map_err(|err| {
+            FocusEventError::InvalidEventId { event_id: event_id.clone(), err: err.to_string() }
+        })?;
+
+        let room = &self.inner;
+
+        let timeline = match matrix_sdk_ui::timeline::Timeline::builder(room)
+            .with_focus(TimelineFocus::Event(parsed_event_id))
+            .build()
+            .await
+        {
+            Ok(t) => t,
+            Err(err) => {
+                if let matrix_sdk_ui::timeline::Error::PaginationError(
+                    PaginationError::Paginator(PaginatorError::EventNotFound(..)),
+                ) = err
+                {
+                    return Err(FocusEventError::EventNotFound { event_id: event_id.to_string() });
+                }
+                return Err(FocusEventError::Other { msg: err.to_string() });
+            }
+        };
+
+        Ok(Timeline::new(timeline))
+    }
+
     pub fn display_name(&self) -> Result<String, ClientError> {
         let r = self.inner.clone();
         RUNTIME.block_on(async move { Ok(r.display_name().await?.to_string()) })