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Bug 1091900 - Introduce a function to create an empty iterator, which simplifies a bunch of stuff. r=efaust

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This commit is contained in:
Tom Schuster
2014-11-19 01:44:02 +01:00
parent ae3ecfd02d
commit 2932b88f97
3 changed files with 120 additions and 107 deletions
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221
js/src/jsiter.cpp
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@@ -566,11 +566,9 @@ VectorToKeyIterator(JSContext *cx, HandleObject obj, unsigned flags, AutoIdVecto
{
MOZ_ASSERT(!(flags & JSITER_FOREACH));
if (obj) {
if (obj->hasSingletonType() && !obj->setIteratedSingleton(cx))
return false;
types::MarkTypeObjectFlags(cx, obj, types::OBJECT_FLAG_ITERATED);
}
if (obj->hasSingletonType() && !obj->setIteratedSingleton(cx))
return false;
types::MarkTypeObjectFlags(cx, obj, types::OBJECT_FLAG_ITERATED);
Rooted<PropertyIteratorObject *> iterobj(cx, NewPropertyIteratorObject(cx, flags));
if (!iterobj)
@@ -618,11 +616,9 @@ js::VectorToValueIterator(JSContext *cx, HandleObject obj, unsigned flags, AutoI
{
MOZ_ASSERT(flags & JSITER_FOREACH);
if (obj) {
if (obj->hasSingletonType() && !obj->setIteratedSingleton(cx))
return false;
types::MarkTypeObjectFlags(cx, obj, types::OBJECT_FLAG_ITERATED);
}
if (obj->hasSingletonType() && !obj->setIteratedSingleton(cx))
return false;
types::MarkTypeObjectFlags(cx, obj, types::OBJECT_FLAG_ITERATED);
Rooted<PropertyIteratorObject*> iterobj(cx, NewPropertyIteratorObject(cx, flags));
if (!iterobj)
@@ -650,6 +646,27 @@ js::EnumeratedIdVectorToIterator(JSContext *cx, HandleObject obj, unsigned flags
return VectorToValueIterator(cx, obj, flags, props, vp);
}
// Mainly used for .. in over null/undefined
bool
js::NewEmptyPropertyIterator(JSContext *cx, unsigned flags, MutableHandleValue vp)
{
Rooted<PropertyIteratorObject*> iterobj(cx, NewPropertyIteratorObject(cx, flags));
if (!iterobj)
return false;
AutoIdVector keys(cx); // Empty
NativeIterator *ni = NativeIterator::allocateIterator(cx, 0, keys);
if (!ni)
return false;
ni->init(nullptr, iterobj, flags, 0, 0);
iterobj->setNativeIterator(ni);
vp.setObject(*iterobj);
RegisterEnumerator(cx, iterobj, ni);
return true;
}
static inline void
UpdateNativeIterator(NativeIterator *ni, JSObject *obj)
{
@@ -661,113 +678,107 @@ UpdateNativeIterator(NativeIterator *ni, JSObject *obj)
bool
js::GetIterator(JSContext *cx, HandleObject obj, unsigned flags, MutableHandleValue vp)
{
if (obj->is<PropertyIteratorObject>() || obj->is<LegacyGeneratorObject>()) {
vp.setObject(*obj);
return true;
}
Vector<Shape *, 8> shapes(cx);
uint32_t key = 0;
bool keysOnly = (flags == JSITER_ENUMERATE);
if (obj) {
if (obj->is<PropertyIteratorObject>() || obj->is<LegacyGeneratorObject>()) {
vp.setObject(*obj);
return true;
}
if (keysOnly) {
/*
* Check to see if this is the same as the most recent object which
* was iterated over. We don't explicitly check for shapeless
* objects here, as they are not inserted into the cache and
* will result in a miss.
*/
PropertyIteratorObject *last = cx->runtime()->nativeIterCache.last;
if (last) {
NativeIterator *lastni = last->getNativeIterator();
if (!(lastni->flags & (JSITER_ACTIVE|JSITER_UNREUSABLE)) &&
obj->isNative() &&
obj->as<NativeObject>().hasEmptyElements() &&
obj->lastProperty() == lastni->shapes_array[0])
{
JSObject *proto = obj->getProto();
if (proto->isNative() &&
proto->as<NativeObject>().hasEmptyElements() &&
proto->lastProperty() == lastni->shapes_array[1] &&
!proto->getProto())
{
vp.setObject(*last);
UpdateNativeIterator(lastni, obj);
RegisterEnumerator(cx, last, lastni);
return true;
}
}
}
/*
* The iterator object for JSITER_ENUMERATE never escapes, so we
* don't care for the proper parent/proto to be set. This also
* allows us to re-use a previous iterator object that is not
* currently active.
*/
if (flags == JSITER_ENUMERATE) {
/*
* Check to see if this is the same as the most recent object which
* was iterated over. We don't explicitly check for shapeless
* objects here, as they are not inserted into the cache and
* will result in a miss.
*/
PropertyIteratorObject *last = cx->runtime()->nativeIterCache.last;
if (last) {
NativeIterator *lastni = last->getNativeIterator();
if (!(lastni->flags & (JSITER_ACTIVE|JSITER_UNREUSABLE)) &&
obj->isNative() &&
obj->as<NativeObject>().hasEmptyElements() &&
obj->lastProperty() == lastni->shapes_array[0])
{
JSObject *pobj = obj;
do {
if (!pobj->isNative() ||
!pobj->as<NativeObject>().hasEmptyElements() ||
IsAnyTypedArray(pobj) ||
pobj->hasUncacheableProto() ||
pobj->getOps()->enumerate ||
pobj->getClass()->enumerate != JS_EnumerateStub ||
pobj->as<NativeObject>().containsPure(cx->names().iteratorIntrinsic))
{
shapes.clear();
goto miss;
}
Shape *shape = pobj->lastProperty();
key = (key + (key << 16)) ^ (uintptr_t(shape) >> 3);
if (!shapes.append(shape))
return false;
pobj = pobj->getProto();
} while (pobj);
}
PropertyIteratorObject *iterobj = cx->runtime()->nativeIterCache.get(key);
if (iterobj) {
NativeIterator *ni = iterobj->getNativeIterator();
if (!(ni->flags & (JSITER_ACTIVE|JSITER_UNREUSABLE)) &&
ni->shapes_key == key &&
ni->shapes_length == shapes.length() &&
Compare(ni->shapes_array, shapes.begin(), ni->shapes_length)) {
vp.setObject(*iterobj);
UpdateNativeIterator(ni, obj);
RegisterEnumerator(cx, iterobj, ni);
if (shapes.length() == 2)
cx->runtime()->nativeIterCache.last = iterobj;
JSObject *proto = obj->getProto();
if (proto->isNative() &&
proto->as<NativeObject>().hasEmptyElements() &&
proto->lastProperty() == lastni->shapes_array[1] &&
!proto->getProto())
{
vp.setObject(*last);
UpdateNativeIterator(lastni, obj);
RegisterEnumerator(cx, last, lastni);
return true;
}
}
}
miss:
if (obj->is<ProxyObject>())
return Proxy::iterate(cx, obj, flags, vp);
/*
* The iterator object for JSITER_ENUMERATE never escapes, so we
* don't care for the proper parent/proto to be set. This also
* allows us to re-use a previous iterator object that is not
* currently active.
*/
{
JSObject *pobj = obj;
do {
if (!pobj->isNative() ||
!pobj->as<NativeObject>().hasEmptyElements() ||
IsAnyTypedArray(pobj) ||
pobj->hasUncacheableProto() ||
pobj->getOps()->enumerate ||
pobj->getClass()->enumerate != JS_EnumerateStub ||
pobj->as<NativeObject>().containsPure(cx->names().iteratorIntrinsic))
{
shapes.clear();
goto miss;
}
Shape *shape = pobj->lastProperty();
key = (key + (key << 16)) ^ (uintptr_t(shape) >> 3);
if (!shapes.append(shape))
return false;
pobj = pobj->getProto();
} while (pobj);
}
if (!GetCustomIterator(cx, obj, flags, vp))
return false;
if (!vp.isUndefined())
return true;
PropertyIteratorObject *iterobj = cx->runtime()->nativeIterCache.get(key);
if (iterobj) {
NativeIterator *ni = iterobj->getNativeIterator();
if (!(ni->flags & (JSITER_ACTIVE|JSITER_UNREUSABLE)) &&
ni->shapes_key == key &&
ni->shapes_length == shapes.length() &&
Compare(ni->shapes_array, shapes.begin(), ni->shapes_length)) {
vp.setObject(*iterobj);
UpdateNativeIterator(ni, obj);
RegisterEnumerator(cx, iterobj, ni);
if (shapes.length() == 2)
cx->runtime()->nativeIterCache.last = iterobj;
return true;
}
}
}
/* NB: for (var p in null) succeeds by iterating over no properties. */
miss:
if (obj->is<ProxyObject>())
return Proxy::iterate(cx, obj, flags, vp);
if (!GetCustomIterator(cx, obj, flags, vp))
return false;
if (!vp.isUndefined())
return true;
AutoIdVector keys(cx);
if (flags & JSITER_FOREACH) {
if (MOZ_LIKELY(obj != nullptr) && !Snapshot(cx, obj, flags, &keys))
return false;
MOZ_ASSERT(shapes.empty());
if (!Snapshot(cx, obj, flags, &keys))
return false;
if (!VectorToValueIterator(cx, obj, flags, keys, vp))
return false;
} else {
if (MOZ_LIKELY(obj != nullptr) && !Snapshot(cx, obj, flags, &keys))
if (!Snapshot(cx, obj, flags, &keys))
return false;
if (!VectorToKeyIterator(cx, obj, flags, keys, shapes.length(), key, vp))
return false;
@@ -1005,17 +1016,17 @@ js::ValueToIterator(JSContext *cx, unsigned flags, MutableHandleValue vp)
if (vp.isObject()) {
/* Common case. */
obj = &vp.toObject();
} else {
} else if ((flags & JSITER_ENUMERATE) && vp.isNullOrUndefined()) {
/*
* Enumerating over null and undefined gives an empty enumerator, so
* that |for (var p in <null or undefined>) <loop>;| never executes
* <loop>, per ES5 12.6.4.
*/
if (!(flags & JSITER_ENUMERATE) || !vp.isNullOrUndefined()) {
obj = ToObject(cx, vp);
if (!obj)
return false;
}
return NewEmptyPropertyIterator(cx, flags, vp);
} else {
obj = ToObject(cx, vp);
if (!obj)
return false;
}
return GetIterator(cx, obj, flags, vp);