Reviewers: rossberg,
Description:
Object.observe: notify when element addition causes array growth
Please review this at https://codereview.chromium.org/11369135/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/objects.cc
M test/mjsunit/harmony/object-observe.js
Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index
570f6fbae4f7c0269db737c7e03ac6a33c0865df..244b732ed85a46aed029026d6a47b1268280450b
100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10307,6 +10307,7 @@ MaybeObject* JSObject::SetElement(uint32_t index,
// From here on, everything has to be handlified.
Handle<String> name;
Handle<Object> old_value(isolate->heap()->the_hole_value());
+ Handle<Object> old_array_length;
PropertyAttributes old_attributes = ABSENT;
bool preexists = false;
if (FLAG_harmony_observation && map()->is_observed()) {
@@ -10317,6 +10318,9 @@ MaybeObject* JSObject::SetElement(uint32_t index,
// TODO(observe): only read & set old_value if we have a data
property
old_value = Object::GetElement(self, index);
}
+ // Store the old array length in case adding an element will grow the
array.
+ if (!preexists && self->IsJSArray())
+ old_array_length = handle(Handle<JSArray>::cast(self)->length());
}
// Check for lookup interceptor
@@ -10332,6 +10336,12 @@ MaybeObject* JSObject::SetElement(uint32_t index,
if (FLAG_harmony_observation && map()->is_observed()) {
PropertyAttributes new_attributes =
self->GetLocalPropertyAttribute(*name);
if (!preexists) {
+ if (self->IsJSArray() &&
+ !old_array_length->SameValue(Handle<JSArray>::cast(self)->length()))
{
+ EnqueueChangeRecord(self, "updated",
+ isolate->factory()->length_symbol(),
+ old_array_length);
+ }
EnqueueChangeRecord(self, "new", name, old_value);
} else if (new_attributes != old_attributes || old_value->IsTheHole())
{
EnqueueChangeRecord(self, "reconfigured", name, old_value);
Index: test/mjsunit/harmony/object-observe.js
diff --git a/test/mjsunit/harmony/object-observe.js
b/test/mjsunit/harmony/object-observe.js
index
231fe91e18594797c5519eec6fbc9f2b839998ef..d4fb48bfe7904618846105e39d85d6c4d35c4b3c
100644
--- a/test/mjsunit/harmony/object-observe.js
+++ b/test/mjsunit/harmony/object-observe.js
@@ -399,3 +399,19 @@ observer.assertCallbackRecords([
{ object: obj, name: "3", type: "new" },
{ object: obj, name: "4", type: "new" },
]);
+
+// Adding elements past the end of an array should notify on length
+reset();
+var arr = [1, 2, 3];
+Object.observe(arr, observer.callback);
+arr[3] = 10;
+arr[100] = 20;
+arr[50] = 30; // no length change expected
+Object.deliverChangeRecords(observer.callback);
+observer.assertCallbackRecords([
+ { object: arr, name: 'length', type: 'updated', oldValue: 3 },
+ { object: arr, name: '3', type: 'new' },
+ { object: arr, name: 'length', type: 'updated', oldValue: 4 },
+ { object: arr, name: '100', type: 'new' },
+ { object: arr, name: '50', type: 'new' },
+]);
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