Description:
Adding support for size to Set and Map

Section 15.14.5.10 and 15.16.5.7 in the October 26, 2012 ES6 draft,
http://wiki.ecmascript.org/doku.php?id=harmony:specification_drafts

This adds a getter for "size" to Set.prototype and Map.prototype which  
reflects
the number of elements in the Set and Map respectively.

BUG=2395

Please review this at https://codereview.chromium.org/11360089/

SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge

Affected files:
   M src/collection.js
   M src/runtime.h
   M src/runtime.cc
   M test/mjsunit/harmony/collections.js

Index: src/collection.js
diff --git a/src/collection.js b/src/collection.js
index  
d36fe18fa00dcd5fdae1210e5f9470c53cbc41f3..f8e3594bb67a8623d8ce63a97f0441271 0f43a8d  
100644
--- a/src/collection.js
+++ b/src/collection.js
@@ -88,6 +88,15 @@ function SetDelete(key) {
  }

+function SetSize() {
+  if (!IS_SET(this)) {
+    throw MakeTypeError('incompatible_method_receiver',
+                        ['Set.prototype.size', this]);
+  }
+  return %SetSize(this);
+}
+
+
  function MapConstructor() {
    if (%_IsConstructCall()) {
      %MapInitialize(this);
@@ -145,6 +154,15 @@ function MapDelete(key) {
  }

+function MapSize() {
+  if (!IS_MAP(this)) {
+    throw MakeTypeError('incompatible_method_receiver',
+                        ['Map.prototype.size', this]);
+  }
+  return %MapSize(this);
+}
+
+
  function WeakMapConstructor() {
    if (%_IsConstructCall()) {
      %WeakMapInitialize(this);
@@ -214,7 +232,16 @@ function WeakMapDelete(key) {
    %SetProperty($Set.prototype, "constructor", $Set, DONT_ENUM);
    %SetProperty($Map.prototype, "constructor", $Map, DONT_ENUM);

+  function DefineGetter(object, name, fun) {
+    %FunctionSetName(fun, name);
+    var desc = new PropertyDescriptor();
+    desc.setGet(fun);
+    desc.setConfigurable(true);
+    DefineObjectProperty(object, name, desc, false);
+  }
+
    // Set up the non-enumerable functions on the Set prototype object.
+  DefineGetter($Set.prototype, "size", SetSize);
    InstallFunctions($Set.prototype, DONT_ENUM, $Array(
      "add", SetAdd,
      "has", SetHas,
@@ -222,6 +249,7 @@ function WeakMapDelete(key) {
    ));

    // Set up the non-enumerable functions on the Map prototype object.
+  DefineGetter($Map.prototype, "size", MapSize);
    InstallFunctions($Map.prototype, DONT_ENUM, $Array(
      "get", MapGet,
      "set", MapSet,
Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index  
b0a6b5e81427e1588a89f1c269a2b1e90c78f98b..861d79f630be5b43f5f122396b2afb025 0c2bc1a  
100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -783,6 +783,15 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_SetDelete) {
  }

+RUNTIME_FUNCTION(MaybeObject*, Runtime_SetSize) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(JSSet, holder, 0);
+  Handle<ObjectHashSet> table(ObjectHashSet::cast(holder->table()));
+  return Smi::FromInt(table->NumberOfElements());
+}
+
+
  RUNTIME_FUNCTION(MaybeObject*, Runtime_MapInitialize) {
    HandleScope scope(isolate);
    ASSERT(args.length() == 1);
@@ -842,6 +851,15 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_MapSet) {
  }

+RUNTIME_FUNCTION(MaybeObject*, Runtime_MapSize) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(JSMap, holder, 0);
+  Handle<ObjectHashTable> table(ObjectHashTable::cast(holder->table()));
+  return Smi::FromInt(table->NumberOfElements());
+}
+
+
  RUNTIME_FUNCTION(MaybeObject*, Runtime_WeakMapInitialize) {
    HandleScope scope(isolate);
    ASSERT(args.length() == 1);
Index: src/runtime.h
diff --git a/src/runtime.h b/src/runtime.h
index  
c8029065f6908ce9f5d04c695dea00ffb098d687..d2126c108a7b2884ad5fd106525b424d7 79d2196  
100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -302,6 +302,7 @@ namespace internal {
    F(SetAdd, 2, 1) \
    F(SetHas, 2, 1) \
    F(SetDelete, 2, 1) \
+  F(SetSize, 1, 1) \
    \
    /* Harmony maps */ \
    F(MapInitialize, 1, 1) \
@@ -309,6 +310,7 @@ namespace internal {
    F(MapHas, 2, 1) \
    F(MapDelete, 2, 1) \
    F(MapSet, 3, 1) \
+  F(MapSize, 1, 1) \
    \
    /* Harmony weakmaps */ \
    F(WeakMapInitialize, 1, 1) \
Index: test/mjsunit/harmony/collections.js
diff --git a/test/mjsunit/harmony/collections.js  
b/test/mjsunit/harmony/collections.js
index  
f3db7ea2b70a9670fa7e63082b2022bbd57f2576..2b9fe3e6f094e088d412b9b93603c5987 f52e717  
100644
--- a/test/mjsunit/harmony/collections.js
+++ b/test/mjsunit/harmony/collections.js
@@ -313,4 +313,43 @@ TestBogusReceivers(bogusReceiversTestSet);
  // Stress Test
  // There is a proposed stress-test available at the es-discuss mailing list
  // which cannot be reasonably automated.  Check it out by hand if you like:
-// https://mail.mozilla.org/pipermail/es-discuss/2011-May/014096.html
\ No newline at end of file
+// https://mail.mozilla.org/pipermail/es-discuss/2011-May/014096.html
+
+
+// Set and Map Set size
+var setSizeDescriptor =  
Object.getOwnPropertyDescriptor(Set.prototype, 'size');
+assertEquals(undefined, setSizeDescriptor.value);
+assertEquals(undefined, setSizeDescriptor.set);
+assertTrue(setSizeDescriptor.get instanceof Function);
+assertFalse(setSizeDescriptor.enumerable);
+assertTrue(setSizeDescriptor.configurable);
+
+var s = new Set();
+assertFalse(s.hasOwnProperty('size'));
+for (var i = 0; i < 10; i++) {
+  assertEquals(i, s.size);
+  s.add(i);
+}
+for (var i = 9; i >= 0; i--) {
+  s.delete(i);
+  assertEquals(i, s.size);
+}
+
+
+var mapSizeDescriptor =  
Object.getOwnPropertyDescriptor(Map.prototype, 'size');
+assertEquals(undefined, mapSizeDescriptor.value);
+assertEquals(undefined, mapSizeDescriptor.set);
+assertTrue(mapSizeDescriptor.get instanceof Function);
+assertFalse(mapSizeDescriptor.enumerable);
+assertTrue(mapSizeDescriptor.configurable);
+
+var m = new Map();
+assertFalse(m.hasOwnProperty('size'));
+for (var i = 0; i < 10; i++) {
+  assertEquals(i, m.size);
+  m.set(i, i);
+}
+for (var i = 9; i >= 0; i--) {
+  m.delete(i);
+  assertEquals(i, m.size);
+}