Shape *
PropertyTree::lookupChild(ThreadSafeContext *cx, Shape *parent, const StackShape &child)
{
/* Keep this in sync with the logic of getChild above. */
Shape *shape = nullptr;
JS_ASSERT(parent);
KidsPointer *kidp = &parent->kids;
if (kidp->isShape()) {
Shape *kid = kidp->toShape();
if (kid->matches(child))
shape = kid;
} else if (kidp->isHash()) {
if (KidsHash::Ptr p = kidp->toHash()->readonlyThreadsafeLookup(child))
shape = *p;
} else {
return nullptr;
}
#if defined(JSGC_INCREMENTAL) && defined(DEBUG)
if (shape) {
JS::Zone *zone = shape->arenaHeader()->zone;
JS_ASSERT(!zone->needsIncrementalBarrier());
JS_ASSERT(!(zone->isGCSweeping() && !shape->isMarked() &&
!shape->arenaHeader()->allocatedDuringIncremental));
}
#endif
return shape;
}
void
PropertyTree::removeChild(Shape *child)
{
JS_ASSERT(!child->inDictionary());
Shape *parent = child->parent;
JS_ASSERT(parent);
JS_ASSERT(!JSID_IS_VOID(parent->id));
KidsPointer *kidp = &parent->kids;
if (kidp->isShape()) {
Shape *kid = kidp->toShape();
if (kid == child)
parent->kids.setNull();
return;
}
kidp->toHash()->remove(child);
}
Shape *
PropertyTree::getChild(JSContext *cx, Shape *parent, const Shape &child)
{
Shape *shape;
JS_ASSERT(parent);
JS_ASSERT(!JSID_IS_VOID(parent->id));
/*
* The property tree has extremely low fan-out below its root in
* popular embeddings with real-world workloads. Patterns such as
* defining closures that capture a constructor's environment as
* getters or setters on the new object that is passed in as
* |this| can significantly increase fan-out below the property
* tree root -- see bug 335700 for details.
*/
KidsPointer *kidp = &parent->kids;
if (kidp->isShape()) {
shape = kidp->toShape();
if (shape->matches(&child))
return shape;
} else if (kidp->isHash()) {
shape = *kidp->toHash()->lookup(&child);
if (shape)
return shape;
} else {
/* If kidp->isNull(), we always insert. */
}
shape = newShape(cx);
if (!shape)
return NULL;
new (shape) Shape(child.id, child.rawGetter, child.rawSetter, child.slot, child.attrs,
child.flags, child.shortid, js_GenerateShape(cx));
if (!insertChild(cx, parent, shape))
return NULL;
return shape;
}
void
Shape::removeChild(Shape *child)
{
JS_ASSERT(!child->inDictionary());
JS_ASSERT(child->parent == this);
KidsPointer *kidp = &kids;
if (kidp->isShape()) {
JS_ASSERT(kidp->toShape() == child);
kidp->setNull();
child->parent = nullptr;
return;
}
KidsHash *hash = kidp->toHash();
JS_ASSERT(hash->count() >= 2); /* otherwise kidp->isShape() should be true */
hash->remove(StackShape(child));
child->parent = nullptr;
if (hash->count() == 1) {
/* Convert from HASH form back to SHAPE form. */
KidsHash::Range r = hash->all();
Shape *otherChild = r.front();
JS_ASSERT((r.popFront(), r.empty())); /* No more elements! */
kidp->setShape(otherChild);
js_delete(hash);
}
}
JS_ALWAYS_INLINE void
js::PropertyTree::orphanChildren(Shape *shape)
{
KidsPointer *kidp = &shape->kids;
JS_ASSERT(!kidp->isNull());
if (kidp->isShape()) {
Shape *kid = kidp->toShape();
if (!JSID_IS_VOID(kid->id)) {
JS_ASSERT(kid->parent == shape);
kid->parent = NULL;
}
} else {
KidsHash *hash = kidp->toHash();
for (KidsHash::Range range = hash->all(); !range.empty(); range.popFront()) {
Shape *kid = range.front();
if (!JSID_IS_VOID(kid->id)) {
JS_ASSERT(kid->parent == shape);
kid->parent = NULL;
}
}
hash->~KidsHash();
js_free(hash);
}
kidp->setNull();
}
bool
PropertyTree::insertChild(JSContext *cx, Shape *parent, Shape *child)
{
JS_ASSERT(!parent->inDictionary());
JS_ASSERT(!child->parent);
JS_ASSERT(!child->inDictionary());
JS_ASSERT(!JSID_IS_VOID(parent->id));
JS_ASSERT(!JSID_IS_VOID(child->id));
JS_ASSERT(cx->compartment == compartment);
JS_ASSERT(child->compartment == parent->compartment);
KidsPointer *kidp = &parent->kids;
if (kidp->isNull()) {
child->setParent(parent);
kidp->setShape(child);
return true;
}
if (kidp->isShape()) {
Shape *shape = kidp->toShape();
JS_ASSERT(shape != child);
JS_ASSERT(!shape->matches(child));
KidsHash *hash = HashChildren(shape, child);
if (!hash) {
JS_ReportOutOfMemory(cx);
return false;
}
kidp->setHash(hash);
child->setParent(parent);
return true;
}
KidsHash *hash = kidp->toHash();
KidsHash::AddPtr addPtr = hash->lookupForAdd(child);
JS_ASSERT(!addPtr.found());
if (!hash->add(addPtr, child)) {
JS_ReportOutOfMemory(cx);
return false;
}
child->setParent(parent);
return true;
}
bool
PropertyTree::insertChild(ExclusiveContext *cx, Shape *parent, Shape *child)
{
JS_ASSERT(!parent->inDictionary());
JS_ASSERT(!child->parent);
JS_ASSERT(!child->inDictionary());
JS_ASSERT(child->compartment() == parent->compartment());
JS_ASSERT(cx->isInsideCurrentCompartment(this));
KidsPointer *kidp = &parent->kids;
if (kidp->isNull()) {
child->setParent(parent);
kidp->setShape(child);
return true;
}
if (kidp->isShape()) {
Shape *shape = kidp->toShape();
JS_ASSERT(shape != child);
JS_ASSERT(!shape->matches(child));
KidsHash *hash = HashChildren(shape, child);
if (!hash) {
js_ReportOutOfMemory(cx);
return false;
}
kidp->setHash(hash);
child->setParent(parent);
return true;
}
if (!kidp->toHash()->putNew(StackShape(child), child)) {
js_ReportOutOfMemory(cx);
return false;
}
child->setParent(parent);
return true;
}
bool
PropertyTree::insertChild(JSContext *cx, UnrootedShape parent, UnrootedShape child)
{
JS_ASSERT(!parent->inDictionary());
JS_ASSERT(!child->parent);
JS_ASSERT(!child->inDictionary());
JS_ASSERT(cx->compartment == compartment);
JS_ASSERT(child->compartment() == parent->compartment());
KidsPointer *kidp = &parent->kids;
if (kidp->isNull()) {
child->setParent(parent);
kidp->setShape(child);
return true;
}
if (kidp->isShape()) {
UnrootedShape shape = kidp->toShape();
JS_ASSERT(shape != child);
JS_ASSERT(!shape->matches(child));
KidsHash *hash = HashChildren(shape, child);
if (!hash) {
JS_ReportOutOfMemory(cx);
return false;
}
kidp->setHash(hash);
child->setParent(parent);
return true;
}
if (!kidp->toHash()->putNew(child, child)) {
JS_ReportOutOfMemory(cx);
return false;
}
child->setParent(parent);
return true;
}
Shape *
PropertyTree::getChild(ExclusiveContext *cx, Shape *parentArg, StackShape &unrootedChild)
{
RootedShape parent(cx, parentArg);
JS_ASSERT(parent);
Shape *existingShape = nullptr;
/*
* The property tree has extremely low fan-out below its root in
* popular embeddings with real-world workloads. Patterns such as
* defining closures that capture a constructor's environment as
* getters or setters on the new object that is passed in as
* |this| can significantly increase fan-out below the property
* tree root -- see bug 335700 for details.
*/
KidsPointer *kidp = &parent->kids;
if (kidp->isShape()) {
Shape *kid = kidp->toShape();
if (kid->matches(unrootedChild))
existingShape = kid;
} else if (kidp->isHash()) {
if (KidsHash::Ptr p = kidp->toHash()->lookup(unrootedChild))
existingShape = *p;
} else {
/* If kidp->isNull(), we always insert. */
}
#ifdef JSGC_INCREMENTAL
if (existingShape) {
JS::Zone *zone = existingShape->zone();
if (zone->needsIncrementalBarrier()) {
/*
* We need a read barrier for the shape tree, since these are weak
* pointers.
*/
Shape *tmp = existingShape;
MarkShapeUnbarriered(zone->barrierTracer(), &tmp, "read barrier");
JS_ASSERT(tmp == existingShape);
} else if (zone->isGCSweeping() && !existingShape->isMarked() &&
!existingShape->arenaHeader()->allocatedDuringIncremental)
{
/*
* The shape we've found is unreachable and due to be finalized, so
* remove our weak reference to it and don't use it.
*/
JS_ASSERT(parent->isMarked());
parent->removeChild(existingShape);
existingShape = nullptr;
}
}
#endif
if (existingShape)
return existingShape;
RootedGeneric<StackShape*> child(cx, &unrootedChild);
Shape *shape = newShape(cx);
if (!shape)
return nullptr;
new (shape) Shape(*child, parent->numFixedSlots());
if (!insertChild(cx, parent, shape))
return nullptr;
return shape;
}
UnrootedShape
PropertyTree::getChild(JSContext *cx, Shape *parent_, uint32_t nfixed, const StackShape &child)
{
AssertCanGC();
{
UnrootedShape shape = NULL;
JS_ASSERT(parent_);
/*
* The property tree has extremely low fan-out below its root in
* popular embeddings with real-world workloads. Patterns such as
* defining closures that capture a constructor's environment as
* getters or setters on the new object that is passed in as
* |this| can significantly increase fan-out below the property
* tree root -- see bug 335700 for details.
*/
KidsPointer *kidp = &parent_->kids;
if (kidp->isShape()) {
UnrootedShape kid = kidp->toShape();
if (kid->matches(child))
shape = kid;
} else if (kidp->isHash()) {
if (KidsHash::Ptr p = kidp->toHash()->lookup(child))
shape = *p;
} else {
/* If kidp->isNull(), we always insert. */
}
#ifdef JSGC_INCREMENTAL
if (shape) {
JS::Zone *zone = shape->zone();
if (zone->needsBarrier()) {
/*
* We need a read barrier for the shape tree, since these are weak
* pointers.
*/
Shape *tmp = shape;
MarkShapeUnbarriered(zone->barrierTracer(), &tmp, "read barrier");
JS_ASSERT(tmp == shape);
} else if (zone->isGCSweeping() && !shape->isMarked() &&
!shape->arenaHeader()->allocatedDuringIncremental)
{
/*
* The shape we've found is unreachable and due to be finalized, so
* remove our weak reference to it and don't use it.
*/
JS_ASSERT(parent_->isMarked());
parent_->removeChild(shape);
shape = NULL;
}
}
#endif
if (shape)
return shape;
}
StackShape::AutoRooter childRoot(cx, &child);
RootedShape parent(cx, parent_);
UnrootedShape shape = newShape(cx);
if (!shape)
return UnrootedShape(NULL);
new (shape) Shape(child, nfixed);
if (!insertChild(cx, parent, shape))
return UnrootedShape(NULL);
return shape;
}
