ES6: Add support for Map and Set Iterator

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 #include <limits>
 
 #include "v8.h"
 
 #include "accessors.h"
@@ skipping 1566 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_SetGetSize) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSSet, holder, 0);
   Handle<OrderedHashSet> table(OrderedHashSet::cast(holder->table()));
   return Smi::FromInt(table->NumberOfElements());
 }
 
 
-RUNTIME_FUNCTION(Runtime_SetCreateIterator) {
+RUNTIME_FUNCTION(Runtime_SetIteratorInitialize) {
   HandleScope scope(isolate);
-  ASSERT(args.length() == 2);
-  CONVERT_ARG_HANDLE_CHECKED(JSSet, holder, 0);
-  CONVERT_SMI_ARG_CHECKED(kind, 1)
+  ASSERT(args.length() == 3);
+  CONVERT_ARG_HANDLE_CHECKED(JSSetIterator, holder, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSSet, set, 1);
+  CONVERT_SMI_ARG_CHECKED(kind, 2)
   RUNTIME_ASSERT(kind == JSSetIterator::kKindValues ||
                  kind == JSSetIterator::kKindEntries);
-  Handle<OrderedHashSet> table(OrderedHashSet::cast(holder->table()));
-  return *JSSetIterator::Create(table, kind);
+  Handle<OrderedHashSet> table(OrderedHashSet::cast(set->table()));
+  holder->set_table(*table);
+  holder->set_index(Smi::FromInt(0));

[Michael Starzinger, 2014/06/02 11:53:36]

Remark: This gives a short window of time during which "index" and "kind" are
initialized to undefined (which is totally fine). The JSSetIteratorVerify
assumes those two fields are always Smi. In the current implementation I don't
see how anything in between the allocation of an iterator and here could cause a
heap verification to be triggered.

I just wanted to leave this comment for posterity. Should there ever be a change
that causes a GC along the way from the constructor to here, then the
verification method needs to be loosened.

[arv (Not doing code reviews), 2014/06/02 23:40:52]

I added  IsUndefined checks to the verifier.

+  holder->set_kind(Smi::FromInt(kind));
+  return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_SetIteratorNext) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSSetIterator, holder, 0);
   return *JSSetIterator::Next(holder);
 }
 
@@ skipping 70 matching lines @@
 
 RUNTIME_FUNCTION(Runtime_MapGetSize) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSMap, holder, 0);
   Handle<OrderedHashMap> table(OrderedHashMap::cast(holder->table()));
   return Smi::FromInt(table->NumberOfElements());
 }
 
 
-RUNTIME_FUNCTION(Runtime_MapCreateIterator) {
+RUNTIME_FUNCTION(Runtime_MapIteratorInitialize) {
   HandleScope scope(isolate);
-  ASSERT(args.length() == 2);
-  CONVERT_ARG_HANDLE_CHECKED(JSMap, holder, 0);
-  CONVERT_SMI_ARG_CHECKED(kind, 1)
+  ASSERT(args.length() == 3);
+  CONVERT_ARG_HANDLE_CHECKED(JSMapIterator, holder, 0);
+  CONVERT_ARG_HANDLE_CHECKED(JSMap, map, 1);
+  CONVERT_SMI_ARG_CHECKED(kind, 2)
   RUNTIME_ASSERT(kind == JSMapIterator::kKindKeys
       || kind == JSMapIterator::kKindValues
       || kind == JSMapIterator::kKindEntries);
-  Handle<OrderedHashMap> table(OrderedHashMap::cast(holder->table()));
-  return *JSMapIterator::Create(table, kind);
+  Handle<OrderedHashMap> table(OrderedHashMap::cast(map->table()));
+  holder->set_table(*table);
+  holder->set_index(Smi::FromInt(0));

[Michael Starzinger, 2014/06/02 11:53:36]

Likewise.

[arv (Not doing code reviews), 2014/06/02 23:40:52]

Done.

+  holder->set_kind(Smi::FromInt(kind));
+  return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_MapIteratorNext) {
   HandleScope scope(isolate);
   ASSERT(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSMapIterator, holder, 0);
   return *JSMapIterator::Next(holder);
 }
 
@@ skipping 13452 matching lines @@
   }
   return NULL;
 }
 
 
 const Runtime::Function* Runtime::FunctionForId(Runtime::FunctionId id) {
   return &(kIntrinsicFunctions[static_cast<int>(id)]);
 }
 
 } }  // namespace v8::internal