/*
* The function tries to scan the whole rope tree using the marking stack as
* temporary storage. If that becomes full, the unscanned ropes are added to
* the delayed marking list. When the function returns, the marking stack is
* at the same depth as it was on entry. This way we avoid using tags when
* pushing ropes to the stack as ropes never leaks to other users of the
* stack. This also assumes that a rope can only point to other ropes or
* linear strings, it cannot refer to GC things of other types.
*/
static void
ScanRope(GCMarker *gcmarker, JSRope *rope)
{
ptrdiff_t savedPos = gcmarker->stack.position();
for (;;) {
JS_ASSERT(GetGCThingTraceKind(rope) == JSTRACE_STRING);
JS_ASSERT(rope->JSString::isRope());
JS_COMPARTMENT_ASSERT_STR(gcmarker->runtime, rope);
JS_ASSERT(rope->isMarked());
JSRope *next = NULL;
JSString *right = rope->rightChild();
if (right->markIfUnmarked()) {
if (right->isLinear())
ScanLinearString(gcmarker, &right->asLinear());
else
next = &right->asRope();
}
JSString *left = rope->leftChild();
if (left->markIfUnmarked()) {
if (left->isLinear()) {
ScanLinearString(gcmarker, &left->asLinear());
} else {
/*
* When both children are ropes, set aside the right one to
* scan it later.
*/
if (next && !gcmarker->stack.push(reinterpret_cast<uintptr_t>(next)))
gcmarker->delayMarkingChildren(next);
next = &left->asRope();
}
}
if (next) {
rope = next;
} else if (savedPos != gcmarker->stack.position()) {
JS_ASSERT(savedPos < gcmarker->stack.position());
rope = reinterpret_cast<JSRope *>(gcmarker->stack.pop());
} else {
break;
}
}
JS_ASSERT(savedPos == gcmarker->stack.position());
}
