Loads in Flash Player, like all web technologies, are asynchronous tasks of some kind (probably a separate thread). They appear to operate on some kind of a delay. If I `trace` each frame out, like in the previous version of `mcl_loadclip`, you get a series of events that look like this:
1. Parent frame 1
2. Parent frame 2
3. Event: onLoadStart
4. Event: onLoadProgress
5. Event: onLoadComplete
6. Parent frame 3
7. Event: onLoadInit
If I run that version of the test on Ruffle, everything happens after frame 1. This is an artifact of how we're testing asynchronous behavior in Ruffle. In order to guarantee test determinism, we have a dummy implementation of `fetch` that does a blocking load, and we poll all futures every frame of execution. This means that there is a very specific order of execution with these tests, which is good for testing, but probably isn't 100% accurate.
Flash Player appears to delay all loads by at least one frame, even loads that are coming from disk which should load immediately. I don't know if this is intentional or not, so I don't want to implement a load delay just for the sake of making tests pass. Ergo, I'm loosening the tests to just test the ability to load and unload movies, and fire events from a loader.
Specifically:
1. `mcl_loadclip` no longer traces out frames of the parent timeline
2. `unloadmovie` et. all use a target movie that doesn't fail the test until 10 frames have passed.
If someone can find a movie network that breaks with fast loading, then I'll consider implementing explicit frame delays for async tasks. Otherwise, this is how we're testing this.
This also adjusts `MovieClip.unloadMovie` to do just that, instead of removing the clip from the display list. We also have to unload clips when loading new movies into them, since `unloadMovie` desugars to loading `""` as the URL.
Interestingly, this constitutes an implementation of `AsBroadcaster`. It appears Macromedia decided to implement event handling on `MovieClipLoader` in a very similar fashion to `AsBroadcaster`, down to invoking `broadcastMessage` and searching a `_listeners` property for listeners.
*De*implement the free function versions of the above, as well as their `Num` variants, since they don't actually exist as callables. Instead, the ActionScript compiler treats them as preprocessor functions that represent various forms of `ActionGetURL`/`ActionGetURL2`.
This function is part of `Avm1`, rather than a hypothetical `LayerManager`, because we're going to need to eventually construct layers differently for AVM2.
This has some subtle problems: we cannot hold references to garbage-collected data in Futures, so we have to arrange for the AVM itself to forcibly root them for us. Then we get them back when our async code is ready to do something to the AVM.
This allows the formation of `'static` futures that can still interact with a player. Async code will need to upgrade the weak reference in order to be able to interact with the player.
Due to some strangeness with the way Rust implemented unsafe-to-move behavior, boxed futures are implicitly `Unpin`. Which is useless to us.
The reason for this is a little counter-intuitive. Actually, the fact that Rust supports memory pinning at all is a little odd, because the core language explicitly requires all types be movable. To get around this, Pin requires that all !Unpin types be *born pinned*. This is because you can't re-pin an already unpinned value in memory.
Anyway, this necessitates this silly API change.
When `_parent` is preloaded in a `DefineFunction2` action,
we previously resolve it on the scope chain. This could cause
double borrow panics as the parent object could already be
borrowed, and also this matches the behavior of the official Flash
player.
Addresses #398.
This is the smallest positive number, not the most negative value.
This is actually the smallest positive subnormal f64, which Rust
does not provide a constant for. This is ~5e-324.
Match Flash's more closely when converting number to string:
* NAN -> NaN
* inf -> Infinity
* -inf -> -Infinity
* Use exponential notation for very large/very small
This is a little bit of a cheat by using Rust's number-to-string
formatting for exponentials, and shoving a sign in front of the
exponent.
David Wendt