wasm-webidl-bindings

Read, write, and manipulate the Wasm WebIDL bindings custom section.

What's Inside

• A parser for the straw proposal text format. See crates/text-parser/src/grammar.lalrpop.

• A set of AST types for representing and manipulating WebIDL bindings. See src/ast.rs.

• An encoder and decoder for the straw proposal binary format. See the implementation at src/binary/encode.rs and details on the format at BINARY.md.

Example

Parsing the Text Format and Encoding it in the Binary Format

```rust

[cfg(feature = "text")]

use wasmwebidlbindings::{binary, text};

// Get the walrus::Module that this webidl-bindings section is for. // // The Wasm type and func that are being bound are: // // (type $EncodeIntoFuncWasm // (param anyref anyref i32 i32) // (result i64 i64)) // // (func $encodeInto // (import "TextEncoder" "encodeInto") // (type $EncodeIntoFuncWasm)) let rawwasm: Vec = getwasmbufferfrom_somewhere();

let mut config = walrus::ModuleConfig::default();

// Register a function to run after the module is parsed, but with access to the // mapping from indices in the original Wasm binary to their newly assigned // walrus IDs. // // This is where we will parse the Web IDL bindings text. config.onparse(|module, indicestoids| { let webidlbindings = text::parse(module, indicestoids, r#" type $TextEncoderEncodeIntoResult (dict (field "read" unsigned long long) (field "written" unsigned long long))

    type $EncodeIntoFuncWebIDL
        (func (method any)
            (param USVString Uint8Array)
            (result $TextEncoderEncodeIntoResult))

    func-binding $encodeIntoBinding import $EncodeIntoFuncWasm $EncodeIntoFuncWebIDL
        (param
            (as any 0)
            (as any 1)
            (view Int8Array 2 3))
        (result
            (as i64 (field 0 (get 0)))
            (as i64 (field 1 (get 0))))

    bind $encodeInto $encodeIntoBinding
"#)?;

println!("The parsed Web IDL bindings are {:#?}", webidl_bindings);

// Insert the `webidl_bindings` into the module as a custom section.
module.customs.add(webidl_bindings);

Ok(())

});

let mut module = config.parse(&raw_wasm)?;

// Reserialize the Wasm module along with its new Web IDL bindings // section. let newrawwasm = module.emit_wasm(); ```