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// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:xi_client/client.dart';
import 'editor.dart';
import 'line_cache.dart';
/// A notification called when the document has changed.
typedef DocumentChangeNotification = void Function(Document event);
/// Stores and manages updates to the state for a Xi document, and provides
/// access to the editing API to the [Editor], via the [XiViewProxy].
class Document extends Stream<Document> implements XiViewHandler {
final LineCache lines = LineCache(TextStyle(color: Colors.black));
final TextStyle _defaultStyle = TextStyle(color: Colors.white);
/// A connection to xi-core.
XiViewProxy _viewProxy;
final StreamController<Document> _controller;
Document() : _controller = StreamController.broadcast();
List<Completer<XiViewProxy>> _pending = [];
/// Provides access to the [XiViewProxy] via a [Future].
///
/// Because view creation is asynchronous, we cannot get a handle to the
/// [XiViewProxy] until after the document has been created. By returning
/// a [Future], we allow the [Editor] to call edit API methods before the
/// view has been resolved.
Future<XiViewProxy> get viewProxy {
if (_viewProxy != null) {
return Future.value(_viewProxy);
}
final completer = Completer();
_pending.add(completer);
return completer.future;
}
// Assigns the XiViewProxy. This should only be called once,
// by the root [XiHandler] when the 'new_view' request first resolves.
void finalizeViewProxy(XiViewProxy newViewProxy) {
assert(_viewProxy == null);
_viewProxy = newViewProxy;
for (var completer in _pending) {
completer.complete(_viewProxy);
}
_pending = null;
_notifyListeners();
}
LineCol _scrollPos = LineCol(line: 0, col: 0);
LineCol get scrollPos => _scrollPos;
double _measureWidth(String s) {
TextSpan span = TextSpan(text: s, style: _defaultStyle);
TextPainter painter =
TextPainter(text: span, textDirection: TextDirection.ltr)..layout();
return painter.width;
}
List<List<double>> measureWidths(List<Map<String, dynamic>> params) {
List<List<double>> result = <List<double>>[];
for (Map<String, dynamic> req in params) {
List<double> inner = <double>[];
List<String> strings = req['strings'];
for (String s in strings) {
inner.add(_measureWidth(s));
}
result.add(inner);
}
return result;
}
void _notifyListeners() {
_controller.add(this);
}
void close() {
_controller.close();
}
@override
void scrollTo(int line, int col) {
_scrollPos = LineCol(line: line, col: col);
_notifyListeners();
}
@override
void update(List<Map<String, dynamic>> params) {
lines.applyUpdate(params);
_notifyListeners();
}
@override
StreamSubscription<Document> listen(void Function(Document event) onData,
{Function onError, void Function() onDone, bool cancelOnError}) {
scheduleMicrotask(_notifyListeners);
return _controller.stream.listen(onData, onError: onError, onDone: onDone);
}
}