1 files changed, 266 insertions, 0 deletions
diff --git a/vendor/maunium.net/go/mautrix/pushrules/condition.go b/vendor/maunium.net/go/mautrix/pushrules/condition.go
new file mode 100644
index 00000000..f809f8e7
--- /dev/null
+++ b/vendor/maunium.net/go/mautrix/pushrules/condition.go
@@ -0,0 +1,266 @@
+// Copyright (c) 2022 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+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"
+)
+
+// Room is an interface with the functions that are needed for processing room-specific push conditions
+type Room interface {
+	GetOwnDisplayname() string
+	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
+
+// The allowed push condition kinds as specified in https://spec.matrix.org/v1.2/client-server-api/#conditions-1
+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.
+type PushCondition struct {
+	// The type of the condition.
+	Kind PushCondKind `json:"kind"`
+	// The dot-separated field of the event to match. Only applicable if kind is EventMatch.
+	Key string `json:"key,omitempty"`
+	// The glob-style pattern to match the field against. Only applicable if kind is EventMatch.
+	Pattern string `json:"pattern,omitempty"`
+	// 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.
+var MemberCountFilterRegex = regexp.MustCompile("^(==|[<>]=?)?([0-9]+)$")
+
+// Match checks if this condition is fulfilled for the given event in the given room.
+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:
+		return cond.matchMemberCount(room)
+	default:
+		return false
+	}
+}
+
+func splitWithEscaping(s string, separator, escape byte) []string {
+	var token []byte
+	var tokens []string
+	for i := 0; i < len(s); i++ {
+		if s[i] == separator {
+			tokens = append(tokens, string(token))
+			token = token[:0]
+		} else if s[i] == escape && i+1 < len(s) {
+			i++
+			token = append(token, s[i])
+		} else {
+			token = append(token, s[i])
+		}
+	}
+	tokens = append(tokens, string(token))
+	return tokens
+}
+
+func hackyNestedGet(data map[string]interface{}, path []string) (interface{}, bool) {
+	val, ok := data[path[0]]
+	if len(path) == 1 {
+		// We don't have any more path parts, return the value regardless of whether it exists or not.
+		return val, ok
+	} else if ok {
+		if mapVal, ok := val.(map[string]interface{}); ok {
+			val, ok = hackyNestedGet(mapVal, path[1:])
+			if ok {
+				return val, true
+			}
+		}
+	}
+	// If we don't find the key, try to combine the first two parts.
+	// e.g. if the key is content.m.relates_to.rel_type, we'll first try data["m"], which will fail,
+	//      then combine m and relates_to to get data["m.relates_to"], which should succeed.
+	path[1] = path[0] + "." + path[1]
+	return hackyNestedGet(data, path[1:])
+}
+
+func stringifyForPushCondition(val interface{}) string {
+	// Implement MSC3862 to allow matching any type of field
+	// https://github.com/matrix-org/matrix-spec-proposals/pull/3862
+	switch typedVal := val.(type) {
+	case string:
+		return typedVal
+	case nil:
+		return "null"
+	case float64:
+		// Floats aren't allowed in Matrix events, but the JSON parser always stores numbers as floats,
+		// so just handle that and convert to int
+		return strconv.FormatInt(int64(typedVal), 10)
+	default:
+		return fmt.Sprint(val)
+	}
+}
+
+func (cond *PushCondition) matchValue(room Room, evt *event.Event) bool {
+	key, subkey, _ := strings.Cut(cond.Key, ".")
+
+	pattern, err := glob.Compile(cond.Pattern)
+	if err != nil {
+		return false
+	}
+
+	switch key {
+	case "type":
+		return pattern.MatchString(evt.Type.String())
+	case "sender":
+		return pattern.MatchString(string(evt.Sender))
+	case "room_id":
+		return pattern.MatchString(string(evt.RoomID))
+	case "state_key":
+		if evt.StateKey == nil {
+			return false
+		}
+		return pattern.MatchString(*evt.StateKey)
+	case "content":
+		// Split the match key with escaping to implement https://github.com/matrix-org/matrix-spec-proposals/pull/3873
+		splitKey := splitWithEscaping(subkey, '.', '\\')
+		// Then do a hacky nested get that supports combining parts for the backwards-compat part of MSC3873
+		val, ok := hackyNestedGet(evt.Content.Raw, splitKey)
+		if !ok {
+			return cond.Pattern == ""
+		}
+		return pattern.MatchString(stringifyForPushCondition(val))
+	default:
+		return false
+	}
+}
+
+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.Raw), &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 {
+		return false
+	}
+
+	msg, ok := evt.Content.Raw["body"].(string)
+	if !ok {
+		return false
+	}
+
+	isAcceptable := func(r uint8) bool {
+		return unicode.IsSpace(rune(r)) || unicode.IsPunct(rune(r))
+	}
+	length := len(displayname)
+	for index := strings.Index(msg, displayname); index != -1; index = strings.Index(msg, displayname) {
+		if (index <= 0 || isAcceptable(msg[index-1])) && (index+length >= len(msg) || isAcceptable(msg[index+length])) {
+			return true
+		}
+		msg = msg[index+len(displayname):]
+	}
+	return false
+}
+
+func (cond *PushCondition) matchMemberCount(room Room) bool {
+	group := MemberCountFilterRegex.FindStringSubmatch(cond.MemberCountCondition)
+	if len(group) != 3 {
+		return false
+	}
+
+	operator := group[1]
+	wantedMemberCount, _ := strconv.Atoi(group[2])
+
+	memberCount := room.GetMemberCount()
+
+	switch operator {
+	case "==", "":
+		return memberCount == wantedMemberCount
+	case ">":
+		return memberCount > wantedMemberCount
+	case ">=":
+		return memberCount >= wantedMemberCount
+	case "<":
+		return memberCount < wantedMemberCount
+	case "<=":
+		return memberCount <= wantedMemberCount
+	default:
+		// Should be impossible due to regex.
+		return false
+	}
+}