1 files changed, 97 insertions, 2 deletions

diff --git a/rust/src/push/evaluator.rs b/rust/src/push/evaluator.rs
index 0365dd01dc..cedd42c54d 100644
--- a/rust/src/push/evaluator.rs
+++ b/rust/src/push/evaluator.rs
@@ -23,6 +23,7 @@ use regex::Regex;
 use super::{
     utils::{get_glob_matcher, get_localpart_from_id, GlobMatchType},
     Action, Condition, EventMatchCondition, FilteredPushRules, KnownCondition,
+    RelatedEventMatchCondition,
 };
 
 lazy_static! {
@@ -49,6 +50,13 @@ pub struct PushRuleEvaluator {
     /// The power level of the sender of the event, or None if event is an
     /// outlier.
     sender_power_level: Option<i64>,
+
+    /// The related events, indexed by relation type. Flattened in the same manner as
+    /// `flattened_keys`.
+    related_events_flattened: BTreeMap<String, BTreeMap<String, String>>,
+
+    /// If msc3664, push rules for related events, is enabled.
+    related_event_match_enabled: bool,
 }
 
 #[pymethods]
@@ -60,6 +68,8 @@ impl PushRuleEvaluator {
         room_member_count: u64,
         sender_power_level: Option<i64>,
         notification_power_levels: BTreeMap<String, i64>,
+        related_events_flattened: BTreeMap<String, BTreeMap<String, String>>,
+        related_event_match_enabled: bool,
     ) -> Result<Self, Error> {
         let body = flattened_keys
             .get("content.body")
@@ -72,6 +82,8 @@ impl PushRuleEvaluator {
             room_member_count,
             notification_power_levels,
             sender_power_level,
+            related_events_flattened,
+            related_event_match_enabled,
         })
     }
 
@@ -156,6 +168,9 @@ impl PushRuleEvaluator {
             KnownCondition::EventMatch(event_match) => {
                 self.match_event_match(event_match, user_id)?
             }
+            KnownCondition::RelatedEventMatch(event_match) => {
+                self.match_related_event_match(event_match, user_id)?
+            }
             KnownCondition::ContainsDisplayName => {
                 if let Some(dn) = display_name {
                     if !dn.is_empty() {
@@ -239,6 +254,79 @@ impl PushRuleEvaluator {
         compiled_pattern.is_match(haystack)
     }
 
+    /// Evaluates a `related_event_match` condition. (MSC3664)
+    fn match_related_event_match(
+        &self,
+        event_match: &RelatedEventMatchCondition,
+        user_id: Option<&str>,
+    ) -> Result<bool, Error> {
+        // First check if related event matching is enabled...
+        if !self.related_event_match_enabled {
+            return Ok(false);
+        }
+
+        // get the related event, fail if there is none.
+        let event = if let Some(event) = self.related_events_flattened.get(&*event_match.rel_type) {
+            event
+        } else {
+            return Ok(false);
+        };
+
+        // If we are not matching fallbacks, don't match if our special key indicating this is a
+        // fallback relation is not present.
+        if !event_match.include_fallbacks.unwrap_or(false)
+            && event.contains_key("im.vector.is_falling_back")
+        {
+            return Ok(false);
+        }
+
+        // if we have no key, accept the event as matching, if it existed without matching any
+        // fields.
+        let key = if let Some(key) = &event_match.key {
+            key
+        } else {
+            return Ok(true);
+        };
+
+        let pattern = if let Some(pattern) = &event_match.pattern {
+            pattern
+        } else if let Some(pattern_type) = &event_match.pattern_type {
+            // The `pattern_type` can either be "user_id" or "user_localpart",
+            // either way if we don't have a `user_id` then the condition can't
+            // match.
+            let user_id = if let Some(user_id) = user_id {
+                user_id
+            } else {
+                return Ok(false);
+            };
+
+            match &**pattern_type {
+                "user_id" => user_id,
+                "user_localpart" => get_localpart_from_id(user_id)?,
+                _ => return Ok(false),
+            }
+        } else {
+            return Ok(false);
+        };
+
+        let haystack = if let Some(haystack) = event.get(&**key) {
+            haystack
+        } else {
+            return Ok(false);
+        };
+
+        // For the content.body we match against "words", but for everything
+        // else we match against the entire value.
+        let match_type = if key == "content.body" {
+            GlobMatchType::Word
+        } else {
+            GlobMatchType::Whole
+        };
+
+        let mut compiled_pattern = get_glob_matcher(pattern, match_type)?;
+        compiled_pattern.is_match(haystack)
+    }
+
     /// Match the member count against an 'is' condition
     /// The `is` condition can be things like '>2', '==3' or even just '4'.
     fn match_member_count(&self, is: &str) -> Result<bool, Error> {
@@ -267,8 +355,15 @@ impl PushRuleEvaluator {
 fn push_rule_evaluator() {
     let mut flattened_keys = BTreeMap::new();
     flattened_keys.insert("content.body".to_string(), "foo bar bob hello".to_string());
-    let evaluator =
-        PushRuleEvaluator::py_new(flattened_keys, 10, Some(0), BTreeMap::new()).unwrap();
+    let evaluator = PushRuleEvaluator::py_new(
+        flattened_keys,
+        10,
+        Some(0),
+        BTreeMap::new(),
+        BTreeMap::new(),
+        true,
+    )
+    .unwrap();
 
     let result = evaluator.run(&FilteredPushRules::default(), None, Some("bob"));
     assert_eq!(result.len(), 3);