| // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| library barback.graph.node_streams; |
| |
| import 'dart:async'; |
| |
| import '../asset/asset_node.dart'; |
| import '../log.dart'; |
| import '../utils/stream_pool.dart'; |
| import 'node_status.dart'; |
| |
| /// A collection of streams that are common to nodes in barback's package graph. |
| class NodeStreams { |
| /// A stream that emits an event every time the node's status changes. |
| /// |
| /// This will emit the new status. It's guaranteed to emit an event only when |
| /// the status changes from the previous value. To ensure this, callers should |
| /// emit status changes using [changeStatus]. The initial status is assumed to |
| /// be [NodeStatus.RUNNING]. |
| Stream<NodeStatus> get onStatusChange => _onStatusChangeController.stream; |
| final _onStatusChangeController = |
| new StreamController<NodeStatus>.broadcast(sync: true); |
| |
| /// A stream that emits any new assets produced by the node. |
| /// |
| /// Assets are emitted synchronously to ensure that any changes are thoroughly |
| /// propagated as soon as they occur. |
| Stream<AssetNode> get onAsset => onAssetPool.stream; |
| final onAssetPool = new StreamPool<AssetNode>.broadcast(); |
| final onAssetController = |
| new StreamController<AssetNode>.broadcast(sync: true); |
| |
| /// A stream that emits an event whenever any the node logs an entry. |
| Stream<LogEntry> get onLog => onLogPool.stream; |
| final onLogPool = new StreamPool<LogEntry>.broadcast(); |
| final onLogController = new StreamController<LogEntry>.broadcast(sync: true); |
| |
| var _previousStatus = NodeStatus.RUNNING; |
| |
| /// Whether [this] has been closed. |
| bool get isClosed => onAssetController.isClosed; |
| |
| NodeStreams() { |
| onAssetPool.add(onAssetController.stream); |
| onLogPool.add(onLogController.stream); |
| } |
| |
| /// Emits a status change notification via [onStatusChange]. |
| /// |
| /// This guarantees that a change notification won't be emitted if the status |
| /// didn't actually change. |
| void changeStatus(NodeStatus status) { |
| if (_previousStatus != status) _onStatusChangeController.add(status); |
| } |
| |
| /// Closes all the streams. |
| void close() { |
| _onStatusChangeController.close(); |
| onAssetController.close(); |
| onAssetPool.close(); |
| onLogController.close(); |
| onLogPool.close(); |
| } |
| } |