Index: pkg/collection/lib/src/canonicalized_map.dart |
diff --git a/pkg/collection/lib/src/canonicalized_map.dart b/pkg/collection/lib/src/canonicalized_map.dart |
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+// 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 dart.pkg.collection.canonicalized_map; |
+ |
+import '../wrappers.dart'; |
+ |
+/** |
+ * A map whose keys are converted to canonical values. |
+ * |
+ * This is useful for using case-insensitive String keys, for example. It's more |
+ * efficient than a [LinkedHashMap] with a custom equality operator because it |
+ * only canonicalizes each once, rather than doing so for each comparison. |
+ */ |
+class CanonicalizedMap<K, V> extends DelegatingMap<K, V> { |
Lasse Reichstein Nielsen
2014/06/27 06:57:47
Could we allow the canonicalization of a key to no
nweiz
2014/06/30 20:37:46
Done.
|
+ final Function _canonicalize; |
+ |
+ /** |
+ * A map from the canonicalized keys to their original values. |
+ */ |
+ final _keys = new Map<K, V>(); |
Lasse Reichstein Nielsen
2014/06/27 06:57:47
Should be <K,K>.
Have you considered using a
nweiz
2014/06/30 20:37:46
Done, using the Pair class that's used elsewhere i
|
+ |
+ /** |
+ * Creates an empty canonicalized map. |
+ * |
+ * The [canonicalize] function should return the canonical value for the given |
+ * key. Keys with the same canonical value are considered identical, and the |
Lasse Reichstein Nielsen
2014/06/27 06:57:47
identical -> equivalent
Ditto below.
nweiz
2014/06/30 20:37:46
Done.
|
+ * canonical values of the keys are stored in the map. |
Lasse Reichstein Nielsen
2014/06/27 06:57:47
"stored in the map" is vague but sounds significan
nweiz
2014/06/30 20:37:46
I just removed this. It was a holdover from before
|
+ */ |
+ CanonicalizedMap(K canonicalize(K key)) |
Lasse Reichstein Nielsen
2014/06/27 06:57:47
I'd also like to have an "bool isValidKey(Object o
Lasse Reichstein Nielsen
2014/06/27 06:57:47
Please see if you can also make the map a paramete
nweiz
2014/06/30 20:37:46
I don't completely understand the purpose of this
nweiz
2014/06/30 20:37:46
I don't think it's worth complicating the API to s
Lasse Reichstein Nielsen
2014/07/01 09:18:14
ACK, if we make the type of canonical object C ins
Lasse Reichstein Nielsen
2014/07/01 09:18:14
I assume that if isValidKey(o) return false, then
nweiz
2014/07/01 21:21:44
Done.
|
+ : _canonicalize = canonicalize, |
+ super({}); |
+ |
+ /** |
+ * Creates a canonicalized map that contains all key/value pairs of [other]. |
Lasse Reichstein Nielsen
2014/06/27 06:57:47
Because of the canonicalization, it might contain
nweiz
2014/06/30 20:37:46
Good point. Done.
|
+ * |
+ * The [canonicalize] function should return the canonical value for the given |
+ * key. Keys with the same canonical value are considered identical, and the |
+ * canonical values of the keys are stored in the map. |
+ */ |
+ CanonicalizedMap.from(Map<K, V> other, K canonicalize(K key)) |
+ : _canonicalize = canonicalize, |
+ super({}) { |
+ addAll(other); |
+ } |
+ |
+ V operator [](Object key) { |
+ if (key != null && key is! K) return null; |
+ return super[_canonicalize(key)]; |
+ } |
+ |
+ void operator []=(K key, V value) { |
+ var canonical = _canonicalize(key); |
+ _keys[canonical] = key; |
+ super[canonical] = value; |
+ } |
+ |
+ void addAll(Map<K, V> other) { |
+ other.forEach((key, value) => this[key] = value); |
+ } |
+ |
+ bool containsKey(Object key) { |
+ if (key != null && key is! K) return null; |
+ return super.containsKey(_canonicalize(key)); |
+ } |
+ |
+ void forEach(void f(K key, V value)) { |
+ super.forEach((key, value) => f(_keys[key], value)); |
+ } |
+ |
+ Iterable<K> get keys => _keys.values; |
+ |
+ V putIfAbsent(K key, V ifAbsent()) { |
+ var canonical = _canonicalize(key); |
+ return super.putIfAbsent(canonical, () { |
+ _keys[canonical] = key; |
+ return ifAbsent(); |
+ }); |
+ } |
+ |
+ V remove(Object key) { |
+ if (key != null && key is! K) return null; |
+ var canonical = _canonicalize(key); |
+ _keys.remove(canonical); |
+ return super.remove(canonical); |
+ } |
+} |