bool
SavedStacks::insertFrames(JSContext *cx, ScriptFrameIter &iter, MutableHandle<SavedFrame*> frame)
{
if (iter.done()) {
frame.set(nullptr);
return true;
}
ScriptFrameIter thisFrame(iter);
Rooted<SavedFrame*> parentFrame(cx);
if (!insertFrames(cx, ++iter, &parentFrame))
return false;
RootedScript script(cx, thisFrame.script());
RootedFunction callee(cx, thisFrame.maybeCallee());
const char *filename = script->filename();
RootedAtom source(cx, Atomize(cx, filename, strlen(filename)));
if (!source)
return false;
uint32_t column;
uint32_t line = PCToLineNumber(script, thisFrame.pc(), &column);
SavedFrame::Lookup lookup(source,
line,
column,
callee ? callee->displayAtom() : nullptr,
parentFrame,
thisFrame.compartment()->principals);
frame.set(getOrCreateSavedFrame(cx, lookup));
return frame.address() != nullptr;
}
bool
SavedStacks::insertFrames(JSContext *cx, FrameIter &iter, MutableHandleSavedFrame frame,
unsigned maxFrameCount)
{
// In order to lookup a cached SavedFrame object, we need to have its parent
// SavedFrame, which means we need to walk the stack from oldest frame to
// youngest. However, FrameIter walks the stack from youngest frame to
// oldest. The solution is to append stack frames to a vector as we walk the
// stack with FrameIter, and then do a second pass through that vector in
// reverse order after the traversal has completed and get or create the
// SavedFrame objects at that time.
//
// To avoid making many copies of FrameIter (whose copy constructor is
// relatively slow), we save the subset of FrameIter's data that is relevant
// to our needs in a FrameState object, and maintain a vector of FrameState
// objects instead of a vector of FrameIter objects.
// Accumulate the vector of FrameState objects in |stackState|.
AutoFrameStateVector stackState(cx);
while (!iter.done()) {
AutoLocationValueRooter location(cx);
{
AutoCompartment ac(cx, iter.compartment());
if (!cx->compartment()->savedStacks().getLocation(cx, iter, &location))
return false;
}
{
FrameState frameState(iter);
frameState.location = location.get();
if (!stackState->append(frameState))
return false;
}
++iter;
if (maxFrameCount == 0) {
// If maxFrameCount is zero, then there's no limit on the number of
// frames.
continue;
} else if (maxFrameCount == 1) {
// Since we were only asked to save one frame, do not continue
// walking the stack and saving frame state.
break;
} else {
maxFrameCount--;
}
}
// Iterate through |stackState| in reverse order and get or create the
// actual SavedFrame instances.
RootedSavedFrame parentFrame(cx, nullptr);
for (size_t i = stackState->length(); i != 0; i--) {
SavedFrame::AutoLookupRooter lookup(cx,
stackState[i-1].location.source,
stackState[i-1].location.line,
stackState[i-1].location.column,
stackState[i-1].name,
parentFrame,
stackState[i-1].principals);
parentFrame.set(getOrCreateSavedFrame(cx, lookup));
if (!parentFrame)
return false;
}
frame.set(parentFrame);
return true;
}
