Previously, we would display an empty string for the method name.
We can now store a `&'static str` again in `NativeMethod`,
instead of needing a `Cow`
* avm2: Implement call stack
* avm2: Class traits should have a special prefix
* avm2: Stack tracebacks should also contain error message
* avm2: Move method naming to Executable
* avm2: Handle getter and setter methods in tracebacks
* chore: Formatting
* chore: Add comments
* avm2: Make full_name write to a string, instead of creating a new one
* core: Make GcArena publicly accessible
* core: Add Deref impl for Either type
* desktop: Add AVM2 call stack to panic message
* avm2: Prefix native methods with a `/`
* chore: Appease clippy
* avm2: Check if method actually contains bytecode instead of unwrapping
* web: Add AVM2 stack trace to panic message
* chore: Formatting
* chore: Clippy
* avm2: Fix stack traces for free standing functions
* core: Remove global data from context
* core: Rename GcGlobalData to GcCallstack
* core: Introduce StaticCallstack, make GcArena private again
Co-authored-by: Adrian Wielgosik <4729533+adrian17@users.noreply.github.com>
This commit adds support for marking methods as `native`
in ActionScript classes defined in playerglobal. The
`build_playerglobal` now checks for native methods, and
generates Rust code linking them to a corresponding Rust
function definition in the codebase.
To test this functionality, I've reimplemented several
functions as native methods (and moved related code to
pure ActionScript).
Testing under Flash shows that methods can be considered 'unchecked'
(allowing them to be called with more arguments than declared
parameters) even if they have a declared return type.
This is relied on by SteamBirds, which registers an event handler
which takes 0 parameters and an explicitly declared return type
This is limited by the fact that we currently cannot store type metadata in static tables. I don't think it's necessary to do so as of yet as pretty much every actual parameter type I *could* shove in here turned out to be optional and broke tests if it wasn't. Still, it's probably useful enough for new classes to include.
I have no idea why this is necessary - I was in a context where what *should* have been a `NativeMethod<'gc>` was instead being interpreted as some different function type with all the same lifetimes, but with an extra `'gc` lifetime as well. Funneling this through a non-trait method bypasses whatever is going on with the trait solver, and then at that point the trait solver knows what to do. Consider this an extra level of conversion.
Holding a `Ref` on a garbage-collected object inherently extends any borrow locks on that object. Since ABC files are references already, taking a `Ref` to them only helps to skip the refcount update. This is less useful than expected: in most situations, using `abc_ref` causes double-borrow panics. The few methods that can use it are going to be fragile in the face of future refactors, so I'm nipping the problem in the bud now.
Interface methods are specifically not allowed to be called: as a result, they don't get a method body. Existing code assumed a 1:1 relationship between methods and bodies, which causes spurious errors.
This is inspired by Dinnerbone's similar PR on the AVM1 side, where the Action half of that VM's `Executable` was reduced from 128 bytes to 16 by shoving it in a `Gc`. This won't be as dramatic but should still save some memory.
In fact, it should save a *lot* of memory in bytecode execution, where thanks to the previous commit's rebase, we now need to clone the current method once *for each instruction executed*. That is terrible, but should stop now.
This also results in a far reduced role for `ReturnValue`, since I also took the liberty of removing most of it's use. Furthermore, I also made it apply equally to native and AVM2 code, which ensures all native implementations of methods don't double-borrow.
In AVM1, `ReturnValue` was actually removed entirely, because it's not needed. I attempted to do the same, but the fact that we're currently embedding `ScriptObjectData` in native objects means that we need it for virtual properties. Otherwise, virtual property implementations will see locked objects, which is bad.