Node's fs APIs resolve relative paths relative to the current working directory:
https://nodejs.org/api/fs.html#fs_file_paths
This creates a problem if you try to require the wasm-bindgen-generated
JavaScript from a different directory. For example, if you have
build/foo.js
build/foo_bg.js
build/foo_bg.wasm
and another script, script/index.js, that requires build/foo.js. We can instead
use __dirname to get the correct path to the file.
As soon as we've removed unneeded exports immediately run a gc pass to ensure
that we don't bind functions in JS that don't actually end up getting needed.
This commit starts wasm-bindgen down the path of supporting closures. We
discussed this at the recent Rust All-Hands but I ended up needing to pretty
significantly scale back the ambitions of what closures are supported. This
commit is just the initial support and provides only a small amount of support
but will hopefully provide a good basis for future implementations.
Specifically this commit adds support for passing `&Fn(...)` to an *imported
function*, but nothing elese. The `&Fn` type can have any lifetime and the JS
object is invalidated as soon as the import returns. The arguments and return
value of `Fn` must currently implement the `WasmAbi` trait, aka they can't
require any conversions like strings/types/etc.
I'd like to soon expand this to `&mut FnMut` as well as `'static` closures that
can be passed around for a long time in JS, but for now I'm putting that off
until later. I'm not currently sure how to implement richer argument types, but
hopefully that can be figured out at some point!
This commit starts wasm-bindgen down a path of removing the special
casing it currently has around vectors, slices, and strings. This has
long been a thorn in wasm-bindgen's side as it doesn't handle other
kinds of vectors and otherwise is very inflexible with future additions.
Additionally it leads to a lot of duplicated-ish code throughout various
portions of codegen.
The fundamental reason for this was that two arguments were required to
be passed back to wasm, and I couldn't figure out a way to shove both
those arguments into a function argument. The new strategy here is that
there is one global stack well known to both JS and Rust which arguments
*may* also be transferred between.
By default all ABI arguments pass as literal function arguments, but if
two or more arguments need to be passed then the extra ones are all
passed through this global stack. The stack is effectively temporary
scratch space when crossing the JS/Rust boundary (both ways). No long
term storage is intended here.
The `simple` test is passing as a result of this commit, using strings
internally. The `Vector` type in the AST has been removed (yay!) and the
bulk of the implementation of slices and vectors now resides in the
`wasm-bindgen` crate itself, defining how to pass all these arguments
around. The JS generator, however, still needs to know about all the
sorts of vectors so it can generate appropriate code for JS.
Future commits will continue cleanup and get the rest of the tests
working.
