refactor(timeline): apply aggregation to TimelineItemContent [CONSIDER SQUASHING]

Author: bnjbvr

crates/matrix-sdk-ui/src/timeline/controller/aggregations.rs

@@ -16,7 +16,7 @@ use std::collections::HashMap;
 
 use ruma::{EventId, MilliSecondsSinceUnixEpoch, OwnedEventId, OwnedUserId};
 
-use crate::timeline::PollState;
+use crate::timeline::{PollState, TimelineItemContent};
 
 #[derive(Clone, Debug)]
 pub(crate) enum Aggregation {
@@ -31,13 +31,30 @@ pub(crate) enum Aggregation {
     },
 }
 
+fn poll_state_from_item(
+    content: &mut TimelineItemContent,
+) -> Result<&mut PollState, AggregationError> {
+    match content {
+        TimelineItemContent::Poll(state) => Ok(state),
+        c => Err(AggregationError::InvalidType {
+            expected: "a poll".to_owned(),
+            actual: c.debug_string().to_owned(),
+        }),
+    }
+}
+
 impl Aggregation {
-    pub fn apply_poll(&self, poll_state: &mut PollState) -> Result<(), AggregationError> {
+    pub fn apply(&self, content: &mut TimelineItemContent) -> Result<(), AggregationError> {
         match self {
             Aggregation::PollResponse { sender, timestamp, answers } => {
-                poll_state.add_response(sender.clone(), *timestamp, answers.clone());
+                poll_state_from_item(content)?.add_response(
+                    sender.clone(),
+                    *timestamp,
+                    answers.clone(),
+                );
             }
             Aggregation::PollEnd { end_date } => {
+                let poll_state = poll_state_from_item(content)?;
                 if !poll_state.end(*end_date) {
                     return Err(AggregationError::PollAlreadyEnded);
                 }
@@ -61,23 +78,26 @@ impl Aggregations {
         self.stashed.entry(event_id).or_default().push(aggregation);
     }
 
-    pub fn apply_poll(
+    pub fn apply(
         &self,
         event_id: &EventId,
-        poll_state: &mut PollState,
-    ) -> Result<(), AggregationError> {
+        content: &mut TimelineItemContent,
+    ) -> Result<bool, AggregationError> {
         let Some(aggregations) = self.stashed.get(event_id) else {
-            return Ok(());
+            return Ok(false);
         };
         for a in aggregations {
-            a.apply_poll(poll_state)?;
+            a.apply(content)?;
         }
-        Ok(())
+        Ok(true)
     }
 }
 
 #[derive(Debug, thiserror::Error)]
 pub(crate) enum AggregationError {
     #[error("trying to end a poll twice")]
     PollAlreadyEnded,
+
+    #[error("trying to apply an aggregation of one type to an invalid target: expected {expected}, actual {actual}")]
+    InvalidType { expected: String, actual: String },
 }

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

@@ -865,49 +865,53 @@ impl<'a, 'o> TimelineEventHandler<'a, 'o> {
             .or(pending_edit)
             .unzip();
 
-        let mut poll_state = PollState::new(c, edit_content);
+        let poll_state = PollState::new(c, edit_content);
+        let mut content = TimelineItemContent::Poll(poll_state);
 
         if let Some(event_id) = self.ctx.flow.event_id() {
             // Applying the cache to remote events only because local echoes
             // don't have an event ID that could be referenced by responses yet.
-            if let Err(err) = self.meta.aggregations.apply_poll(event_id, &mut poll_state) {
+            if let Err(err) = self.meta.aggregations.apply(event_id, &mut content) {
                 warn!("discarding poll aggregations: {err}");
             }
         }
 
         let edit_json = edit_json.flatten();
 
-        self.add_item(TimelineItemContent::Poll(poll_state), edit_json);
+        self.add_item(content, edit_json);
     }
 
     fn handle_poll_response(&mut self, c: UnstablePollResponseEventContent) {
         let start_event_id = c.relates_to.event_id;
 
-        self.meta.aggregations.add(
-            start_event_id.clone(),
-            Aggregation::PollResponse {
-                sender: self.ctx.sender.clone(),
-                timestamp: self.ctx.timestamp,
-                answers: c.poll_response.answers.clone(),
-            },
-        );
-
-        let Some((item_pos, item)) = rfind_event_by_id(self.items, &start_event_id) else {
-            return;
+        let aggregation = Aggregation::PollResponse {
+            sender: self.ctx.sender.clone(),
+            timestamp: self.ctx.timestamp,
+            answers: c.poll_response.answers,
         };
+        self.meta.aggregations.add(start_event_id.clone(), aggregation.clone());
 
-        let TimelineItemContent::Poll(poll_state) = item.content() else {
+        let Some((item_pos, item)) = rfind_event_by_id(self.items, &start_event_id) else {
             return;
         };
 
-        let mut new_poll = poll_state.clone();
-        new_poll.add_response(self.ctx.sender.clone(), self.ctx.timestamp, c.poll_response.answers);
-
-        let new_item = item.with_content(TimelineItemContent::Poll(new_poll), None);
-
-        trace!("Adding poll response.");
-        self.items.replace(item_pos, TimelineItem::new(new_item, item.internal_id.to_owned()));
-        self.result.items_updated += 1;
+        let mut new_content = item.content().clone();
+        match aggregation.apply(&mut new_content) {
+            Ok(()) => {
+                trace!("adding poll response.");
+                self.items.replace(
+                    item_pos,
+                    TimelineItem::new(
+                        item.with_content(new_content, None),
+                        item.internal_id.clone(),
+                    ),
+                );
+                self.result.items_updated += 1;
+            }
+            Err(err) => {
+                warn!("discarding poll response: {err}");
+            }
+        }
     }
 
     fn handle_poll_end(&mut self, c: UnstablePollEndEventContent) {
@@ -920,21 +924,15 @@ impl<'a, 'o> TimelineEventHandler<'a, 'o> {
             return;
         };
 
-        let TimelineItemContent::Poll(poll_state) = item.content() else {
-            return;
-        };
-
-        let mut poll_state = poll_state.clone();
-
-        match aggregation.apply_poll(&mut poll_state) {
+        let mut new_content = item.content().clone();
+        match aggregation.apply(&mut new_content) {
             Ok(()) => {
                 trace!("Ending poll.");
-                let new_item = item.with_content(TimelineItemContent::Poll(poll_state), None);
+                let new_item = item.with_content(new_content, None);
                 self.items
                     .replace(item_pos, TimelineItem::new(new_item, item.internal_id.to_owned()));
                 self.result.items_updated += 1;
             }
-
             Err(err) => {
                 warn!("discarding poll end: {err}");
             }