Implement MSC3664

matrix-org/matrix-spec-proposals#3664

Author: tulir

pushrules/condition.go

@@ -7,13 +7,17 @@
 package pushrules
 
 import (
+	"encoding/json"
 	"fmt"
 	"regexp"
 	"strconv"
 	"strings"
 	"unicode"
 
+	"github.com/tidwall/gjson"
+
 	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
 	"maunium.net/go/mautrix/pushrules/glob"
 )
 
@@ -23,6 +27,12 @@ type Room interface {
 	GetMemberCount() int
 }
 
+// EventfulRoom is an extension of Room to support MSC3664.
+type EventfulRoom interface {
+	Room
+	GetEvent(id.EventID) *event.Event
+}
+
 // PushCondKind is the type of a push condition.
 type PushCondKind string
 
@@ -31,6 +41,11 @@ const (
 	KindEventMatch          PushCondKind = "event_match"
 	KindContainsDisplayName PushCondKind = "contains_display_name"
 	KindRoomMemberCount     PushCondKind = "room_member_count"
+
+	// MSC3664: https://github.com/matrix-org/matrix-spec-proposals/pull/3664
+
+	KindRelatedEventMatch         PushCondKind = "related_event_match"
+	KindUnstableRelatedEventMatch PushCondKind = "im.nheko.msc3664.related_event_match"
 )
 
 // PushCondition wraps a condition that is required for a specific PushRule to be used.
@@ -44,6 +59,9 @@ type PushCondition struct {
 	// The condition that needs to be fulfilled for RoomMemberCount-type conditions.
 	// A decimal integer optionally prefixed by ==, <, >, >= or <=. Prefix "==" is assumed if no prefix found.
 	MemberCountCondition string `json:"is,omitempty"`
+
+	// The relation type for related_event_match from MSC3664
+	RelType event.RelationType `json:"rel_type,omitempty"`
 }
 
 // MemberCountFilterRegex is the regular expression to parse the MemberCountCondition of PushConditions.
@@ -54,6 +72,8 @@ func (cond *PushCondition) Match(room Room, evt *event.Event) bool {
 	switch cond.Kind {
 	case KindEventMatch:
 		return cond.matchValue(room, evt)
+	case KindRelatedEventMatch, KindUnstableRelatedEventMatch:
+		return cond.matchRelatedEvent(room, evt)
 	case KindContainsDisplayName:
 		return cond.matchDisplayName(room, evt)
 	case KindRoomMemberCount:
@@ -148,6 +168,47 @@ func (cond *PushCondition) matchValue(room Room, evt *event.Event) bool {
 	}
 }
 
+func (cond *PushCondition) getRelationEventID(relatesTo *event.RelatesTo) id.EventID {
+	if relatesTo == nil {
+		return ""
+	}
+	switch cond.RelType {
+	case "":
+		return relatesTo.EventID
+	case "m.in_reply_to":
+		if relatesTo.IsFallingBack || relatesTo.InReplyTo == nil {
+			return ""
+		}
+		return relatesTo.InReplyTo.EventID
+	default:
+		if relatesTo.Type != cond.RelType {
+			return ""
+		}
+		return relatesTo.EventID
+	}
+}
+
+func (cond *PushCondition) matchRelatedEvent(room Room, evt *event.Event) bool {
+	var relatesTo *event.RelatesTo
+	if relatable, ok := evt.Content.Parsed.(event.Relatable); ok {
+		relatesTo = relatable.OptionalGetRelatesTo()
+	} else {
+		res := gjson.GetBytes(evt.Content.VeryRaw, `m\.relates_to`)
+		if res.Exists() && res.IsObject() {
+			_ = json.Unmarshal([]byte(res.Str), &relatesTo)
+		}
+	}
+	if evtID := cond.getRelationEventID(relatesTo); evtID == "" {
+		return false
+	} else if eventfulRoom, ok := room.(EventfulRoom); !ok {
+		return false
+	} else if evt = eventfulRoom.GetEvent(relatesTo.EventID); evt == nil {
+		return false
+	} else {
+		return cond.matchValue(room, evt)
+	}
+}
+
 func (cond *PushCondition) matchDisplayName(room Room, evt *event.Event) bool {
 	displayname := room.GetOwnDisplayname()
 	if len(displayname) == 0 {

pushrules/condition_test.go

@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/assert"
 
 	"maunium.net/go/mautrix/event"
+	"maunium.net/go/mautrix/id"
 	"maunium.net/go/mautrix/pushrules"
 )
 
@@ -104,12 +105,15 @@ func TestPushCondition_Match_InvalidKind(t *testing.T) {
 type FakeRoom struct {
 	members map[string]*event.MemberEventContent
 	owner   string
+
+	events map[id.EventID]*event.Event
 }
 
 func newFakeRoom(memberCount int) *FakeRoom {
 	room := &FakeRoom{
 		owner:   "@tulir:maunium.net",
 		members: make(map[string]*event.MemberEventContent),
+		events:  make(map[id.EventID]*event.Event),
 	}
 
 	if memberCount >= 1 {
@@ -141,3 +145,7 @@ func (fr *FakeRoom) GetOwnDisplayname() string {
 	}
 	return ""
 }
+
+func (fr *FakeRoom) GetEvent(evtID id.EventID) *event.Event {
+	return fr.events[evtID]
+}

pushrules/rule_test.go

@@ -64,7 +64,7 @@ func TestPushRule_Match_Conditions_NestedKey_Boolean(t *testing.T) {
 		Conditions: []*pushrules.PushCondition{cond1},
 	}
 
-	evt := newFakeEvent(event.EventMessage, &event.MemberEventContent{
+	evt := newFakeEvent(event.StateMember, &event.MemberEventContent{
 		Membership: "invite",
 	})
 	assert.False(t, rule.Match(blankTestRoom, evt))
@@ -86,7 +86,7 @@ func TestPushRule_Match_Conditions_EscapedKey(t *testing.T) {
 		Conditions: []*pushrules.PushCondition{cond1},
 	}
 
-	evt := newFakeEvent(event.EventMessage, &event.MemberEventContent{
+	evt := newFakeEvent(event.StateMember, &event.MemberEventContent{
 		Membership: "invite",
 	})
 	assert.False(t, rule.Match(blankTestRoom, evt))
@@ -102,7 +102,7 @@ func TestPushRule_Match_Conditions_EscapedKey_NoNesting(t *testing.T) {
 		Conditions: []*pushrules.PushCondition{cond1},
 	}
 
-	evt := newFakeEvent(event.EventMessage, &event.MemberEventContent{
+	evt := newFakeEvent(event.StateMember, &event.MemberEventContent{
 		Membership: "invite",
 	})
 	assert.False(t, rule.Match(blankTestRoom, evt))
@@ -112,6 +112,34 @@ func TestPushRule_Match_Conditions_EscapedKey_NoNesting(t *testing.T) {
 	assert.False(t, rule.Match(blankTestRoom, evt))
 }
 
+func TestPushRule_Match_Conditions_RelatedEvent(t *testing.T) {
+	cond1 := &pushrules.PushCondition{
+		Kind:    pushrules.KindRelatedEventMatch,
+		Key:     "sender",
+		Pattern: "@tulir:maunium.net",
+	}
+	rule := &pushrules.PushRule{
+		Type:       pushrules.OverrideRule,
+		Enabled:    true,
+		Conditions: []*pushrules.PushCondition{cond1},
+	}
+
+	evt := newFakeEvent(event.EventReaction, &event.ReactionEventContent{
+		RelatesTo: event.RelatesTo{
+			Type:    event.RelAnnotation,
+			EventID: "$meow",
+			Key:     "🐈️",
+		},
+	})
+	roomWithEvent := newFakeRoom(1)
+	assert.False(t, rule.Match(roomWithEvent, evt))
+	roomWithEvent.events["$meow"] = newFakeEvent(event.EventMessage, &event.MessageEventContent{
+		MsgType: event.MsgEmote,
+		Body:    "is testing pushrules",
+	})
+	assert.True(t, rule.Match(roomWithEvent, evt))
+}
+
 func TestPushRule_Match_Conditions_Disabled(t *testing.T) {
 	cond1 := newMatchPushCondition("content.msgtype", "m.emote")
 	cond2 := newMatchPushCondition("content.body", "*pushrules")