Move usersWithRole() function to a dedicated file and make it a documented extension of MatrixRoom.

features/roomdetails/impl/src/main/kotlin/io/element/android/features/roomdetails/impl/rolesandpermissions/changeroles/ChangeRolesPresenter.kt

@@ -42,6 +42,7 @@ import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.room.MatrixRoom
 import io.element.android.libraries.matrix.api.room.RoomMember
 import io.element.android.libraries.matrix.api.room.powerlevels.UserRoleChange
+import io.element.android.libraries.matrix.api.room.powerlevels.usersWithRole
 import io.element.android.libraries.matrix.api.room.toMatrixUser
 import io.element.android.libraries.matrix.api.user.MatrixUser
 import io.element.android.services.analytics.api.AnalyticsService

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/MatrixRoom.kt

@@ -35,13 +35,8 @@ import io.element.android.libraries.matrix.api.timeline.MatrixTimeline
 import io.element.android.libraries.matrix.api.timeline.ReceiptType
 import io.element.android.libraries.matrix.api.widget.MatrixWidgetDriver
 import io.element.android.libraries.matrix.api.widget.MatrixWidgetSettings
-import kotlinx.collections.immutable.ImmutableList
-import kotlinx.collections.immutable.toPersistentList
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.distinctUntilChanged
-import kotlinx.coroutines.flow.map
 import java.io.Closeable
 import java.io.File
 
@@ -183,17 +178,6 @@ interface MatrixRoom : Closeable {
     suspend fun canUserJoinCall(userId: UserId): Result<Boolean> =
         canUserSendState(userId, StateEventType.CALL_MEMBER)
 
-    fun usersWithRole(role: RoomMember.Role): Flow<ImmutableList<RoomMember>> {
-        return roomInfoFlow
-            .map { it.userPowerLevels.filter { (_, powerLevel) -> RoomMember.Role.forPowerLevel(powerLevel) == role } }
-            .combine(membersStateFlow) { powerLevels, membersState ->
-                membersState.joinedRoomMembers()
-                    .filter { powerLevels.containsKey(it.userId) }
-                    .toPersistentList()
-            }
-            .distinctUntilChanged()
-    }
-
     suspend fun updateAvatar(mimeType: String, data: ByteArray): Result<Unit>
 
     suspend fun removeAvatar(): Result<Unit>

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/powerlevels/MatrixRoomMembersWithRole.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2024 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.libraries.matrix.api.room.powerlevels
+
+import io.element.android.libraries.matrix.api.room.MatrixRoom
+import io.element.android.libraries.matrix.api.room.RoomMember
+import io.element.android.libraries.matrix.api.room.joinedRoomMembers
+import kotlinx.collections.immutable.ImmutableList
+import kotlinx.collections.immutable.toPersistentList
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.map
+
+/**
+ * Return a flow of the list of room members who are still in the room (with membership == RoomMembershipState.JOIN)
+ * and who have the given role.
+ */
+fun MatrixRoom.usersWithRole(role: RoomMember.Role): Flow<ImmutableList<RoomMember>> {
+    return roomInfoFlow
+        .map { it.userPowerLevels.filter { (_, powerLevel) -> RoomMember.Role.forPowerLevel(powerLevel) == role } }
+        .combine(membersStateFlow) { powerLevels, membersState ->
+            membersState.joinedRoomMembers()
+                .filter { powerLevels.containsKey(it.userId) }
+                .toPersistentList()
+        }
+        .distinctUntilChanged()
+}