Methods `onSetFocus` & `onKillFocus` are invoked when focus is changed
for `TextField`, `Button`, and `MovieClip`.
Multiple SWFs use these methods to listen to a focus change,
e.g. in order to implement placeholders for text fields.
This ensures that a re-entrant 'construct_frame' call (e.g. due
to a goto or AVM2 button) does not end up marking a MovieClip as
initialized too early.
This issue was causing us to run 'fire_init_and_complete_events' too
early, firing Loader events before we had actually finished (and
before the SWF had registered the relevant listeners).
An Avm2 button appears to run a 'nested frame' during construction -
the same type of 'nested frame' performed by a goto. This will
run framescripts for all objects in the display hierarchy (including
orphans), resulting in an unusual child->parent framescript execution
order that DeathVsMonstars_decrypted.swf depends on.
This allows us to hide things like `MovieClip.isPlaying` from older
SWFs, which may define an `isPlaying` method without marking it
as an override.
This has the largest impact on public namespaces. There is no longer
just one public namespace - we now have a public namespace per API
version. Most callsites should use `Avm2.find_public_namespace()`,
which determines the public namespace based on the root SWF API version.
This ensures that explicit property access in Ruffle (e.g. calling
"toString") are able to see things defined in the user SWF.
This requires several changes other:
* A new `ApiVersion` enum is introduced, storing all of the api versions
defined in avmplus
* NamespaceData::Namespace now holds an `ApiVersion`. When we read a
namespace from a user-defined ABC file, we use the `ApiVersion` from
the root movie clip. This matches Flash Player's behavior - when a
child SWF is loaded through `Loader`, its API version gets overwritten
with the parent's API version, which affects definition visibility and
'override' requirements in the child SWF. Note that 'behavior changes'
in methods like `gotoAndPlay` are unaffected.
* The `PartialEq` impl for `Namespace` has been removed - each call site must now choose
to compare namespaces either by an exact version match, or by
'compatible' versions (a `<=` check) with `Namespace::matches_ns`
* `PropertyMap` now uses `Namespace::matches_ns` to check for a
compatible version when looking up a definition.
* When compiling our playerglobal, we pass in the `-apiversioning` flag,
which causes asc.jar to convert `[API]` metadata into a special
Unicode 'version mark' suffix in namespace URLs. We parse this
when loading namespaces to determine the API version to use for
playerglobal definitions (unmarked definitions use the lowest possible
version).
Unfortunately, this makes ffdec unable to decompile our
playerglobal.swc
I've going to file an upstream issue
Normally, Flash Player will ignores frames for a movie clip with
a symbol class that doesn't extend `MovieClip` (e.g. it extends
`Sprite`). However, the root movie appears to have frame run
unconditionally, even if it only extends `Sprite`. This can
be observed by adding a Graphics child in the second frame only -
the child will flicker in and out as the player switches between
frames, but only for the root movie clip.
Seedling relies on this behavior - it has `DoAbc2` tags in the second
frame, and has a main `Preloader` class that extends `Sprite`.