This test technically works, but the results were slightly surprising. If it turns out Flash works differently from `quick_xml`, we'll change this test to match Flash.
`quick_xml` was chosen due to it's high performance and support for zero-copy use cases. However, we are not using `minidom`, which is the already-extant DOM impl that uses `quick_xml` as it's parsing provider. This is because `minidom` nodes are not amenable to garbage collection.
Specifically: we want to be able to construct a new `Object` variant that holds part of an XML node. However, `minidom::Element` directly owns it's children, meaning that we can't hold references to it from within `Object` while also keeping those objects to the `'gc` lifetime. Hence, we provide a GC-exclusive DOM implementation.
I ruled out solutions such as holding an entire XML tree in an `Rc` and having AVM objects that shadow them. This works for `SwfSlice` because indexing an array is cheap; but traversing a tree can get very expensive. XML is used in many places in Flash Player, so it's important that we treat it like a first-class citizen.
If a button event had both a keyPress condition and another
condition:
on(release, keyPress "A") { }
these actions would not fire on click, because it would still
check if the key was down (which doesn't apply to clicks!)
Fixes#195.
A lot of the arithmetic ops were still using SWFv4 style coercion
(`Value::into_number_v1`) even though they use full ECMA-262
coercion in SWF5+. This would cause `undefined` to turn into 0
isntead of NaN, for example.
Fixes disappearing player in Achievement Unlocked
(https://www.newgrounds.com/portal/view/474371)
It's possible even the older ops such as ActionAdd should do this,
too. Handcrafted bytecode will need to be used to test as you
cannot export these ops in newer SWF versions from the Flash IDE.
ActionAnd, ActionOr, and ActionNot were incorrectly comparing
to 0. This only works for SWF<4. Now they all go through the
Value::as_bool method to handle version specific behavior.
Value::from_bool_v1 was also renamed to Value::from_bool.
Functions now store their base clip (the code that contains the
executing bytecode). This is because `GotoFrame` and other actions
will execute on the clip the bytecode exists on, not on `this`.
(Note that `this.gotoAndStop` uses `GetMember` actions, which
worked correctly).
`Activation` now stores `target_clip`, and `Avm1::target_clip` and
`target_clip_or_root` grab this from the current stack frame.
Renamed `start_clip` to `base_clip` to match Flash conventions.
Removed `active_clip` as this was superfluous. Now you can use
`Avm1::target_clip_or_root`.
`UpdateContext` no longer contains `target_clip` etc.
Add a check and clear the stack if it isn't empty at the end of
`run_stack_till_empty`. This is probably a bug on our side
and we a good place for breakpoints.
When running an clip event handler (e.g. onEnterFrame), a stack
frame is pushed to get the property value. However, this frame
was causing an extra Undefined to be pushed on the operand stack in
`Avm1::retire_stack_frame`, which would blow out the stack.
Now this stack frame is popped after the property is resolved and
before the function is executed. The function will push its own
stack frame when it executes.
This is a very rough stub out of Stage.width and height to get
basic V-cams to start functioning.
TODO: Implement the different stage scaling modes. We will probably
want to add a "Stage" display object to handle this.
DoAction was accidentally creating its stack frame using
Avm1::insert_stack_frame_for_init_action, causing a dummy
Undefined to be pushed and blowing out the stack.
Fire unload clip event when a movie clip is removed. Added
`ActionType` enum used by `ActionQueue::queue_actions` that
determines the type of action that is running (replaces `is_init`
parameter).
This requires some subclassing nonsense to be able to smuggle a self-reference into `SuperObject`s. When successfully smuggled, all calls to `call` will be invoked with the `super` object as `this`. This allows constructor chaining to work.
Note that not all `Object` trait methods are implemented on `SuperObject`, so things like `delete this.x` in super constructors will randomly fail. This should be fixed.
We implement `super` by way of a new `Object` impl which wraps arbitrary objects with a modified prototype chain. Specifically, the lowest layer of the prototype chain is omitted. This new `SuperObject` script is composable: a chain of two `SuperObject`s will go two levels of inheritance upwards while still maintaining non-prototype property access.
Add DisplayObject::slash_path to get the Flash 4-style slash path
to the clip. This fixes the tellTarget regression test and removes
the superfluous `target_path` from `UpdateContext`.
DisplayObject code no longer has to manage
UpdateContext::active_clip before calling out to children, because
each child still has access to its Gc pointer.
This was discovered almost by accident: @Dinnerbone noticed that `_global == null`, and surmised that `valueOf` was the culprit. However, this doesn't really make sense: `_global` is a bare object, so it shouldn't have a `valueOf` (and in practice, it doesn't).
The ultimate cause of such an odd comparison is as such:
1. Flash coerces the `_global` object to a numerical primitive by calling `valueOf`.
2. `_global.valueOf` is undefined. Flash handles calls to any uncallable value by literally just having it return `undefined`. In other words, all values are implicitly callable as empty functions.
3. `undefined` is then compared to `null`. These two values *are* equal under abstract equality (`==`). Hence, `_global == null`.
For comparison, modern ECMAScript engines throw errors on calls to uncallable values; and won't attempt to use an invalid `valueOf` to coerce objects. So none of this applies to, say, standard JavaScript in your browser.
In Flash, this also at least claims to halt ActionScript execution on the movie. No such implementation of AVM poisoning currently exists in Ruffle, primarily because it's unclear what gets poisoned and implementing some of these options isn't yet possible:
1. AVM (e.g. all movies) - we would need to make the AVM fail silently in this case. This is the most straightforward way to poison the movie, but I'm not sure if this is how Flash actually does it, or if it poisons...
2. Movie - the current structure of movies is incompatible with adding arbitrary data to them. We need to merge `moviefetch` in before we can attach data to loaded movies.
3. MovieClip - this would also be implementable but has problems. How do child MovieClips know that their parent has been poisoned, or vice versa? What if a movie clip is loaded from one movie and moved into another?
As a result, I have decided to hold off on implementing recursion poisoning until I know where it's supposed to go and how to implement that.
While I don't expect every host object to implement it correctly, this also gets rid of a lot of unnecessary `unwrap` calls that would allow a poorly-written Flash file to kill the interpreter.
Note that host objects that do so will *not* have access to their standard representation from within member functions - you will need to extend the interface to accomodate for them. This is due to long-standing limitations with type IDs and downcasting with types that bear lifetimes - it's entirely an unsafe operation and exposing such a facility to safe Rust is unsound. However, this will at least let us separate out several things from ScriptObject that don't need to be there for the time being.
`Object::function` now returns a pre-allocated function object. You may supply it an explicit prototype to have it linked into the function object (which is why we have to return a cell).