- Revert r24564 and r24563 due to unexplained malloc corruption.

runtime/lib/expando_patch.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.
 
 patch class Expando<T> {
-  /* patch */ Expando([this.name])
-      : _data = new List(_minSize),
-        _used = 0;
-
-  static const _minSize = 8;
-  static final _deletedEntry = new _WeakProperty(null, null);
+  /* patch */ Expando([this.name]) : _data = new List();
 
   /* patch */ T operator[](Object object) {
     _checkType(object);
-
-    var mask = _size - 1;
-    var idx = object.hashCode & mask;
-    var wp = _data[idx];
-
-    while (wp != null) {
-      if (identical(wp.key, object)) {
-        return wp.value;
-      } else if (wp.key == null) {
-        // This entry has been cleared by the GC.
-        _data[idx] = _deletedEntry;
+    var doCompact = false;
+    var result = null;
+    for (int i = 0; i < _data.length; ++i) {
+      var key = _data[i].key;
+      if (identical(key, object)) {
+        result = _data[i].value;
+        break;
       }
-      idx = (idx + 1) & mask;
-      wp = _data[idx];
+      if (key == null) {
+        doCompact = true;
+        _data[i] = null;
+      }
     }
-
-    return null;
+    if (doCompact) {
+      _data = _data.where((e) => (e != null)).toList();
+    }
+    return result;
   }
 
   /* patch */ void operator[]=(Object object, T value) {
     _checkType(object);
-
-    var mask = _size - 1;
-    var idx = object.hashCode & mask;
-    var empty_idx = -1;
-    var wp = _data[idx];
-
-    while (wp != null) {
-      if (identical(wp.key, object)) {
-        if (value != null) {
-          // Update the associated value.
-          wp.value = value;
-        } else {
-          // Mark the entry as deleted.
-          _data[idx] = _deletedEntry;
-        }
-        return;
-      } else if ((empty_idx < 0) && identical(wp, _deletedEntry)) {
-        empty_idx = idx;  // Insert at this location if not found.
-      } else if (wp.key == null) {
-        // This entry has been cleared by the GC.
-        _data[idx] = _deletedEntry;
-        if (empty_idx < 0) {
-          empty_idx = idx;  // Insert at this location if not found.
-        }
+    var doCompact = false;
+    int i = 0;
+    for (; i < _data.length; ++i) {
+      var key = _data[i].key;
+      if (identical(key, object)) {
+        break;
       }
-      idx = (idx + 1) & mask;
-      wp = _data[idx];
-    }
-
-    if (value == null) {
-      // Not entering a null value. We just needed to make sure to clear an
-      // existing value if it existed. 
-      return;
-    }
-
-    if (empty_idx >= 0) {
-      // We will be reusing the empty slot below.
-      _used--;
-      idx = empty_idx;
-    }
-
-    if (_used < _limit) {
-      _data[idx] = new _WeakProperty(object, value);
-      _used++;
-      return;
-    }
-
-    // Grow/reallocate if too many slots have been used.
-    _rehash();
-    this[object] = value;  // Recursively add the value.
-  }
-
-  _rehash() {
-    // Determine the population count of the map to allocate an appropriately
-    // sized map below.
-    var count = 0;
-    var old_data = _data;
-    var len = old_data.length;
-    for (var i = 0; i < len; i++) {
-      var entry = old_data[i];
-      if ((entry != null) && (entry.key != null)) {
-        // Only count non-cleared entries.
-        count++;
+      if (key == null) {
+        doCompact = true;
+        _data[i] = null;
       }
     }
-
-    var new_size = _size;
-    if (count <= (new_size >> 2)) {
-      new_size = new_size >> 1;
-    } else if (count > (new_size >> 1)) {
-      new_size = new_size << 1;
+    if (i != _data.length && value == null) {
+      doCompact = true;
+      _data[i] = null;
+    } else if (i != _data.length) {
+      _data[i].value = value;
+    } else {
+      _data.add(new _WeakProperty(object, value));
     }
-    new_size = (new_size < _minSize) ? _minSize : new_size;
-
-    // Reset the mappings to empty so that we can just add the existing
-    // valid entries.
-    _data = new List(new_size);
-    _used = 0;
-
-    for (var i = 0; i < old_data.length; i++) {
-      var entry = old_data[i];
-      if ((entry != null) && (entry.key != null)) {
-        this[entry.key] = entry.value;
-      }
+    if (doCompact) {
+      _data = _data.where((e) => (e != null)).toList();
     }
   }
 
   static _checkType(object) {
-    if ((object == null) ||
-         (object is bool) ||
-         (object is num) ||
-         (object is String)) {
+    if (object == null || object is bool || object is num || object is String) {
       throw new ArgumentError(object);
     }
   }
 
-  get _size => _data.length;
-  get _limit => (3 * (_size ~/ 4));
-
   List _data;
-  int _used;  // Number of used (active and deleted) slots.
 }