ES6 Map/Set iterators/forEach improvements

test/mjsunit/harmony/collections.js

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@@ skipping 834 matching lines @@
 
   var accumulated = 0;
   map.forEach(function(v) {
     accumulated += v;
     if (v % 10 === 0) {
       gc();
     }
   });
   assertEquals(4950, accumulated);
 })();
+
+
+(function TestMapForEachAllRemovedTransition() {
+  var map = new Map;
+  map.set(0, 0);
+
+  var buffer = [];
+  map.forEach(function(v) {
+    buffer.push(v);
+    if (v === 0) {
+      for (var i = 1; i < 4; i++) {
+        map.set(i, i);
+      }
+    }
+
+    if (v === 3) {
+      for (var i = 0; i < 4; i++) {
+        map.delete(i);
+      }
+      for (var i = 4; i < 8; i++) {
+        map.set(i, i);
+      }
+    }
+  });
+
+  assertArrayEquals([0, 1, 2, 3, 4, 5, 6, 7], buffer);
+})();
+
+
+(function TestMapForEachClearTransition() {
+  var map = new Map;
+  map.set(0, 0);
+
+  var i = 0;
+  var buffer = [];
+  map.forEach(function(v) {
+    buffer.push(v);
+    if (++i < 5) {
+      for (var j = 0; j < 5; j++) {
+        map.clear();
+        map.set(i, i);
+      }
+    }
+  });
+
+  assertArrayEquals([0, 1, 2, 3, 4], buffer);
+})();
+
+
+(function TestMapForEachNestedNonTrivialTransition() {
+  var map = new Map;
+  map.set(0, 0);
+
+  var i = 0;
+  var buffer = [];
+  map.forEach(function(v) {
+    buffer.push(v);
+
+    if (++i > 16) return;
+
+    if (v % 8 == 0) {
+      for (var j = 1; j <= 8; j++) {
+        map.set(v + j, v + j);
+      }
+    }
+
+    if (v % 2 == 0) {
+      map.delete(v + 1);

[rossberg, 2014/05/16 16:10:18]

If I read this correctly, this only ever deletes to the right of the iterator,
which means that it never needs to adjust to a different index. Can you tweak
the test such that the iterator actually has to change, preferably at each step
of the multi-transition?

[arv (Not doing code reviews), 2014/05/20 00:29:58]

Changed this test. It now has a 4 iteration transition where it has to update
the index in 3 of those 4 transitions.

+      map.delete(v + 3);
+    }
+  });
+
+  for (var i = 0; i <= 16; i++) {
+    assertEquals(buffer[i], i * 2);
+  }
+})();
+
+
+(function TestMapForEachAllRemovedTransitionNoClear() {
+  var map = new Map;
+  map.set(0, 0);
+
+  var buffer = [];
+  map.forEach(function(v) {
+    buffer.push(v);
+    if (v === 0) {
+      for (var i = 1; i < 8; i++) {
+        map.set(i, i);
+      }
+    }
+
+    if (v === 4) {
+      for (var i = 0; i < 8; i++) {
+        map.delete(i);
+      }
+    }
+  });
+
+  assertArrayEquals([0, 1, 2, 3, 4], buffer);
+})();
+
+
+(function TestMapForEachNoMoreElementsAfterTransition() {
+  var map = new Map;
+  map.set(0, 0);
+
+  var buffer = [];
+  map.forEach(function(v) {
+    buffer.push(v);
+    if (v === 0) {
+      for (var i = 1; i < 16; i++) {
+        map.set(i, i);
+      }
+    }
+
+    if (v === 4) {
+      for (var i = 5; i < 16; i++) {
+        map.delete(i);
+      }
+    }
+  });
+
+  assertArrayEquals([0, 1, 2, 3, 4], buffer);
+})();