List.unmodifiable

tool/input_sdk/private/js_array.dart

 // Copyright (c) 2012, 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.
 
 part of dart._interceptors;
 
 /**
  * The interceptor class for [List]. The compiler recognizes this
  * class as an interceptor, and changes references to [:this:] to
  * actually use the receiver of the method, which is generated as an extra
@@ skipping 18 matching lines @@
   factory JSArray.markGrowable(allocation) = JSArray<E>.typed;
 
   static List markFixedList(List list) {
     // Functions are stored in the hidden class and not as properties in
     // the object. We never actually look at the value, but only want
     // to know if the property exists.
     JS('void', r'#.fixed$length = Array', list);
     return list;
   }
 
+  static List markUnmodifiableList(List list) {
+    // Functions are stored in the hidden class and not as properties in
+    // the object. We never actually look at the value, but only want
+    // to know if the property exists.
+    JS('void', r'#.fixed$length = Array', list);
+    JS('void', r'#.immutable$list = Array', list);
+    return JS('JSUnmodifiableArray', '#', list);
+  }
+
+  checkMutable(reason) {
+    if (JS('bool', r'#.immutable$list', this)) {
+      throw new UnsupportedError(reason);
+    }
+  }
+
   checkGrowable(reason) {
     if (JS('bool', r'#.fixed$length', this)) {
       throw new UnsupportedError(reason);
     }
   }
 
   void add(E value) {
     checkGrowable('add');
     JS('void', r'#.push(#)', this, value);
   }
@@ skipping 258 matching lines @@
     JS('void', r'#.length = #', this, newLength);
   }
 
   E operator [](int index) {
     if (index is !int) throw new ArgumentError(index);
     if (index >= length || index < 0) throw new RangeError.value(index);
     return JS('var', '#[#]', this, index);
   }
 
   void operator []=(int index, E value) {
+    checkMutable('indexed set');
     if (index is !int) throw new ArgumentError(index);
     if (index >= length || index < 0) throw new RangeError.value(index);
     JS('void', r'#[#] = #', this, index, value);
   }
 
   Map<int, E> asMap() {
     return new IterableMixinWorkaround<E>().asMapList(this);
   }
 }
 
 /**
  * Dummy subclasses that allow the backend to track more precise
  * information about arrays through their type. The CPA type inference
  * relies on the fact that these classes do not override [] nor []=.
  */
 class JSMutableArray<E> extends JSArray<E> implements JSMutableIndexable {}
 class JSFixedArray<E> extends JSMutableArray<E> {}
 class JSExtendableArray<E> extends JSMutableArray<E> {}
+class JSUnmodifiableArray<E> extends JSArray<E> {} // Already is JSIndexable.