Index: sdk/lib/_internal/lib/js_array.dart |
diff --git a/sdk/lib/_internal/lib/js_array.dart b/sdk/lib/_internal/lib/js_array.dart |
index 32c0c8cbc67f760fda7f80c2aa8d5b2fb28ffea0..bc6ae8391c253c62acf43734d85914a6408e7ea1 100644 |
--- a/sdk/lib/_internal/lib/js_array.dart |
+++ b/sdk/lib/_internal/lib/js_array.dart |
@@ -14,6 +14,66 @@ class JSArray<E> extends Interceptor implements List<E>, JSIndexable { |
const JSArray(); |
+ /** |
+ * Returns a fresh JavaScript Array, marked as fixed-length. |
+ * |
+ * [length] must be a non-negative integer. |
+ */ |
+ factory JSArray.fixed(int length) { |
+ // Explicit type test is necessary to guard against JavaScript conversions |
+ // in unchecked mode. |
+ if ((length is !int) || (length < 0)) { |
+ throw new ArgumentError("Length must be a non-negative integer: $length"); |
+ } |
+ return new JSArray<E>.markFixed(JS('', 'new Array(#)', length)); |
+ } |
+ |
+ /** |
+ * Returns a fresh growable JavaScript Array of zero length length. |
+ */ |
+ factory JSArray.emptyGrowable() => new JSArray<E>.markGrowable(JS('', '[]')); |
+ |
+ /** |
+ * Returns a fresh growable JavaScript Array with initial length. |
+ * |
+ * [validatedLength] must be a non-negative integer. |
+ */ |
+ factory JSArray.growable(int length) { |
+ // Explicit type test is necessary to guard against JavaScript conversions |
+ // in unchecked mode. |
+ if ((length is !int) || (length < 0)) { |
+ throw new ArgumentError("Length must be a non-negative integer: $length"); |
+ } |
+ return new JSArray<E>.markGrowable(JS('', 'new Array(#)', length)); |
+ } |
+ |
+ /** |
+ * Constructor for adding type parameters to an existing JavaScript Array. |
+ * The compiler specially recognizes this constructor. |
+ * |
+ * var a = new JSArray<int>.typed(JS('JSExtendableArray', '[]')); |
+ * a is List<int> --> true |
+ * a is List<String> --> false |
+ * |
+ * Usually either the [JSArray.markFixed] or [JSArray.markGrowable] |
+ * constructors is used instead. |
+ * |
+ * The input must be a JavaScript Array. The JS form is just a re-assertion |
+ * to help type analysis when the input type is sloppy. |
+ */ |
+ factory JSArray.typed(allocation) => JS('JSArray', '#', allocation); |
+ |
+ factory JSArray.markFixed(allocation) => |
+ JS('JSFixedArray', '#', markFixedList(new JSArray<E>.typed(allocation))); |
+ |
+ factory JSArray.markGrowable(allocation) => |
+ JS('JSExtendableArray', '#', new JSArray<E>.typed(allocation)); |
+ |
+ static List markFixedList(List list) { |
+ JS('void', r'#.fixed$length = #', list, true); |
+ return JS('JSFixedArray', '#', list); |
+ } |
+ |
checkMutable(reason) { |
if (this is !JSMutableArray) { |
throw new UnsupportedError(reason); |
@@ -174,9 +234,9 @@ class JSArray<E> extends Interceptor implements List<E>, JSIndexable { |
throw new RangeError.range(end, start, length); |
} |
} |
- // TODO(ngeoffray): Parameterize the return value. |
- if (start == end) return []; |
- return JS('JSExtendableArray', r'#.slice(#, #)', this, start, end); |
+ if (start == end) return <E>[]; |
+ return new JSArray<E>.markGrowable( |
+ JS('', r'#.slice(#, #)', this, start, end)); |
} |
@@ -268,8 +328,13 @@ class JSArray<E> extends Interceptor implements List<E>, JSIndexable { |
String toString() => IterableMixinWorkaround.toStringIterable(this, '[', ']'); |
- List<E> toList({ bool growable: true }) => |
- new List<E>.from(this, growable: growable); |
+ List<E> toList({ bool growable: true }) { |
+ if (growable) { |
+ return new JSArray<E>.markGrowable(JS('', '#.slice()', this)); |
+ } else { |
+ return new JSArray<E>.markFixed(JS('', '#.slice()', this)); |
+ } |
+ } |
Set<E> toSet() => new Set<E>.from(this); |
@@ -309,6 +374,6 @@ class JSArray<E> extends Interceptor implements List<E>, JSIndexable { |
* information about arrays through their type. The CPA type inference |
* relies on the fact that these classes do not override [] nor []=. |
*/ |
-class JSMutableArray extends JSArray implements JSMutableIndexable {} |
-class JSFixedArray extends JSMutableArray {} |
-class JSExtendableArray extends JSMutableArray {} |
+class JSMutableArray<E> extends JSArray<E> implements JSMutableIndexable {} |
+class JSFixedArray<E> extends JSMutableArray<E> {} |
+class JSExtendableArray<E> extends JSMutableArray<E> {} |