When adding support for mutable slices I was under the impression that if the
wasm memory was reallocated while we were using it then we'd have to commit the
changes from the original buffer back to the new buffer. What I didn't know,
however, is that once the wasm memory is reallocated then all views into it are
supposed to be defunkt.
It looks like node 9 didn't have this implementation quite right and it appears
fixed in node 10, causing the deleted test here to fail. While this commit does
raise the question of whether this is the right approach to interact with slices
in JS I think the answer is still "yes". The user can always initiate the copy
if need be and that seems strictly better than copying 100% of the time.
This commit updates the `Abi` associated type for all slice types to a
`WasmSlice` type, an aggregate of two `u32` integers. This translates to an ABI
where when passed as a function argument it expands to two integer arguments,
and when passed as a return value it passes a return pointer as the first
argument to get filled in.
This is hopefully more forwards-compatible with the host bindings proposal which
uses this strategy for passing string arguments at least. It's a little sketchy
what we're doing as there's not really a stable ABI yet, but hopefully this'll
all be relatively stable for awhile!
This commit adds support for mutable slices to pass the boundary between JS and
Rust. While mutable slices cannot be used as return values they can be listed as
arguments to both exported functions as well as imported functions.
When passing a mutable slice into a Rust function (aka having it as an argument
to an exported Rust function) then like before with a normal slice it's copied
into the wasm memory. Afterwards, however, the updates in the wasm memory will
be reflected back into the original slice. This does require a lot of copying
and probably isn't the most efficient, but it should at least work for the time
being.
The real nifty part happens when Rust passes a mutable slice out to JS. When
doing this it's a very cheap operation that just gets a subarray of the main
wasm memory. Now the wasm memory's buffer can change over time which can produce
surprising results where memory is modified in JS but it may not be reflected
back into Rust. To accomodate this when a JS imported function returns any
updates to the buffer are copied back to Rust if Rust's memory buffer has
changed in the meantime.
Along the way this fixes usage of `slice` to instead use `subarray` as that's
what we really want, no copying. All methods have been updated to use `subarray`
accessors instead of `slice` or constructing new arrays.
Closes#53
This commit adds an example of executing the `wasm2asm` tool to generate asm.js
output instead of WebAssembly. This is often useful when supporting older
browsers, such as IE 11, that doesn't have native support for WebAssembly.
Currently `#[wasm_bindgen]` generates a bunch of references to symbols that
don't actually exist on non-wasm targets, making it more difficult to get a
crate working across multiple platforms. This commit updates the symbol
references to be dummy ones that panic on non-wasm targets to allow simple
testing/benchmarking to work on native targets.
While this isn't a perfect solution for #114 it's probably as good as we can do
for now pending upstream Cargo features, so I'm gonna say that it...
Closes#114
These functions are activated with the `serde-serialization` feature of the
`wasm-bindgen` crate. When activated they will allow passing any arbitrary value
into JS that implements the `Serialize` trait and receiving any value from JS
using the `Deserialize` trait. The interchange between JS and Rust is JSON.
Closes#96
This commit adds a `#[wasm_bindgen(version = "...")]` attribute support. This
information is eventually written into a `__wasm_pack_unstable` section.
Currently this is a strawman for the proposal in ashleygwilliams/wasm-pack#101
Turns out there was a bug when passing a vector of `JsValue` instances back to
JS all objects were leaked rather than correctly removed from the global slab.
This commit fixes how the `getArrayJsValueFromWasm` function is defined to
correctly iterate over the slice by looking at the values rather than the
indices.
Closes#169
Using `proc-macro2`'s `nightly` feature is a good default for most use cases.
However, it causes a build error if used together with crates such as
`cssparser` that also use `proc-macro2` from a build script.
This change adds a default enabled feature `spans` that users can disable if
they need to work around this conflict.
Fixes#160.
Currently errors are reported via Rust panics but there's lots more errors being
added over time so this commit starts the movement towards the `failure` crate
to more idiomatically report errors as well as provide better error messages
over time.
The previous codegen wasn't enough to convince LLVM that the function pointer
was a constant value and could be aggressively inlined, so this updates the
`JsStatic` internals slightly to guarantee to LLVM that the function pointer is
constant and no dynamic dispatch is needed after all
Add support for `#[wasm_bindgen(readonly)]` which indicates that an exported
struct field is readonly and attempting to set it in JS will throw an exception.
Closes#151
Automatically infer public struct fields as "JS wants to access this" and
generate appropriate getters/setters for the field. At this time the field is
required to implement `Copy`, but we will probably want to relax that in the
future to at least encompass `JsValue` and maybe other `Clone` values as well.
Closes#121
Currently the entire `Program` is deserialized to match schema versions but this
is likely to fail when the schema changes. Instead just deserialize the
schema/version fields, compare those, and if successful go ahead and deserialize
everything.
