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// Copyright (c) 2018, 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.
import 'dart:collection';
import '../path.dart' as p;
/// A map whose keys are paths, compared using [p.equals] and [p.hash].
class PathMap<V> extends MapView<String?, V> {
/// Creates an empty [PathMap] whose keys are compared using `context.equals`
/// and `context.hash`.
///
/// The [context] defaults to the current path context.
PathMap({p.Context? context}) : super(_create(context));
/// Creates a [PathMap] with the same keys and values as [other] whose keys
/// are compared using `context.equals` and `context.hash`.
///
/// The [context] defaults to the current path context. If multiple keys in
/// [other] represent the same logical path, the last key's value will be
/// used.
PathMap.of(Map<String, V> other, {p.Context? context})
: super(_create(context)..addAll(other));
/// Creates a map that uses [context] for equality and hashing.
static Map<String?, V> _create<V>(p.Context? context) {
context ??= p.context;
return LinkedHashMap(
equals: (path1, path2) {
if (path1 == null) return path2 == null;
if (path2 == null) return false;
return context!.equals(path1, path2);
},
hashCode: (path) => path == null ? 0 : context!.hash(path),
isValidKey: (path) => path is String || path == null);
}
}