Code like this:
```
var body: ?*ElementHTML = undefined;
const err = documentHTMLVtable(doc_html).get_body.?(doc_html, &body);
try DOMErr(err);
if (body == null) return null;
return @as(*Body, @ptrCast(body.?));
```
Isn't safe. It assumes that libdom will either return an error, or set body
to null or a value. However, there are cases (specifically for this API) where
libdom returns DOM_NO_ERR without ever setting body. In such cases, we return
a `body` initialized to a random (invalid) value.
This PR replaces the initial value of optional types from undefined to null
(within the libdom wrapper).
Rather than stack-allocating MAX_MESSAGE_SIZE upfront, we now allocate 32KB
and grow the buffer as needed for larger messages, up to MAX_MESSAGE_SIZE.
This will reduce memory usage for drivers that don't send huge payloads (like
playwright does).
While not implemented, this would also enable us to set the MAX_MESSAGE_SIZE
at runtime (e.g. via a command line option).
Removes optional platform, which only existed for tests.
There is now a global `@import("testing.zig").test_app` available. This is setup
when the test runner starts, and cleaned up at the end of tests. Individual
tests don't have to worry about creating app, which I assume was the reason I
Platform optional, since that woul dhave been something else that needed to be
setup.
This should load the "src.js":
```
const s = document.createElement('script');
document.getElementsByTagName('body')[0].appendChild(s);
s.src = "src.js"
```
Notice that src is set AFTER the element is added to the DOM. This PR enables
the above, by
1 - skipping dynamically added scripts which don't have a src
2 - trying to load a script whenever `set_src` is called.
(2) is safe because the ScriptManager already prevents scripts from being
processed multiple times.
Additionally, not only can the src be set after the script is added to the DOM,
but onload and onerror can be set after the src:
```
s.src = "src.js"
s.onload = ...;
s.onerror = ...;
```
This PR also delays reading the onload/onerror callbacks until the script is
done loading.
This behavior is seen on reddit.
