We were interpreting "undefined" as a variable lookup failure in some
cases and throwing a ReferenceError exception instead of treating it
as the valid value "undefined".
This patch wraps the result of variable lookup in Optional<>, which
allows us to only throw ReferenceError when lookup actually fails.
We currently use icon paths for this because I didn't want to deal with
implementing icon bitmap sharing right now. In the future it would be
better to post a bitmap somehow instead of a path.
Since NotificationServer is a spawn-on-demand + die-when-not-used type
of service, we can't expect a singleton connection to it to remain open
and useful.
We solve this for now by making a new IPC connection for every new
notification sent. Maybe there's a better solution for this.
Getting the innerHTML property will recurse through the subtree inside
the element and serialize it into a string as it goes.
Setting it will parse the set value as an HTML fragment. It will then
remove all current children of the element and replace them with all
the children inside the parsed fragment.
Setting element.innerHTML will currently force a complete rebuild of
the document's layout tree.
This is pretty neat! :^)
This function allows you to throw away the entire layout tree if that's
something you want to do.
It's certainly not super cheap to reconstruct, but hey, who am I to
tell you what to do? :^)
You can now throw an expression to the nearest catcher! :^)
To support throwing arbitrary values, I added an Exception class that
sits as a wrapper around whatever is thrown. In the future it will be
a logical place to store a call stack.
You can now throw exceptions by calling Interpreter::throw_exception().
Anyone who calls ASTNode::execute() needs to check afterwards if the
Interpreter now has an exception(), and if so, stop what they're doing
and simply return.
When catching an exception, we'll first execute the CatchClause node
if present. After that, we'll execute the finalizer block if present.
This is unlikely to be completely correct, but it's a start! :^)
This momentarily handles the CSS property "position: absolute;" in
combination with the properties "top" and "left", so that elements can
be placed anywhere on the page independently from their parents.
Statically positioned elements ignore absolute positioned elements when
calculating their position as they don't take up space.
We can now handle scripts with if/else in LibJS. Most of the changes
are about fixing IfStatement to store the consequent and alternate node
as Statements.
Interpreter now also runs Statements, rather than running ScopeNodes.
When the Heap is going down, it's our last chance to run destructors,
so add a separate collector mode where we simply skip over the marking
phase and go directly to sweeping. This causes everything to get swept
and all live cells get destroyed.
This way, valgrind reports 0 leaks on exit. :^)
We now support rAF, driven by GUI::DisplayLink callbacks. It's a bit
strange how we keep registering new callbacks over and over.
That's something we can definitely optimize.
This allows you to update animations/whatever without doing it more
often than the browser can display.
This patch adds GUI::DisplayLink, a mechanism for registering callbacks
that will fire at the display refresh rate.
Note that we don't actually know the screen refresh rate, but this is
instead completely driven by WindowServer's compositing timer. For all
current intents and purposes it does the job well enough. :^)
