This allows the host of LibJS (notably LibWeb in this case) to override
certain functions such as HostEnqueuePromiseJob, so it can do it's own
thing in certain situations. Notably, LibWeb will override
HostEnqueuePromiseJob to put promise jobs on the microtask queue.
This also makes promise jobs use AK::Function instead of
JS::NativeFunction. This removes the need to go through a JavaScript
function and it more closely matches the spec's idea of "abstract
closures"
The environment settings object is effectively the context a piece of
script is running under, for example, it contains the origin,
responsible document, realm, global object and event loop for the
current context. This effectively replaces ScriptExecutionContext, but
it cannot be removed in this commit as EventTarget still depends on it.
https://html.spec.whatwg.org/multipage/webappapis.html#environment-settings-object
Since VM::exception() no longer exists this is now useless. All of these
calls to clear_exception were just to clear the VM state after some
(potentially) failed evaluation and did not use the exception itself.
This commit removes all exception related code:
Remove VM::exception(), VM::throw_exception() etc. Any leftover
throw_exception calls are moved to throw_completion.
The one method left is clear_exception() which is now a no-op. Most of
these calls are just to clear whatever exception might have been thrown
when handling a Completion. So to have a cleaner commit this will be
removed in a next commit.
It also removes the actual Exception and TemporaryClearException classes
since these are no longer used.
In any spot where the exception was actually used an attempt was made to
preserve that behavior. However since it is no longer tracked by the VM
we cannot access exceptions which were thrown in previous calls.
There are two such cases which might have different behavior:
- In Web::DOM::Document::interpreter() the on_call_stack_emptied hook
used to print any uncaught exception but this is now no longer
possible as the VM does not store uncaught exceptions.
- In js the code used to be interruptable by throwing an exception on
the VM. This is no longer possible but was already somewhat fragile
before as you could happen to throw an exception just before a VERIFY.
This removes a number of vm.exception() checks which are now caught
directly by TRY. Make use of these checks in
{Global, Eval}DeclarationInstantiation and while we're here add spec
comments.
The current implementation of step 2a sort of manually implemented GetV
with a ToObject + Get combo. But in the call to Get, the receiver wasn't
the correct object. So when invoking toJSON, the receiver was an Object
type rather than a BigInt.
This also adds spec comments to SerializeJSONProperty.
Since the spec does not fully define the entry points of modules what
this means is kind of unclear. But it does work in most cases and can
be useful. We do print out a warning just to clarify why there could be
strange things.
This feature had bitrotted somewhat and would trigger errors because
PrimitiveStrings were "destroyed" but because of this mode they were not
removed from the string cache. Even fixing that case running test-js
with the options still failed in more places.
LibRegex already implements this loop in a more performant way, so all
LibJS has to do here is to return things in the right shape, and not
loop over the input string.
Previously this was a quadratic operation on string length, which lead
to crazy execution times on failing regexps - now it's nice and fast :^)
Note that a Regex test has to be updated to remove the stateful flag as
it repeats matching on multiple strings.
This is a normative change in the ECMA-262 spec:
ca53334
Note that this also fixes a few errors where we errantly converted the
stored time value to local time.
