commit 14e27cfa89bdd3a917e2da3f8eb300fd5884e79c
Author: Ivan Enderlin <ivan.enderlin@hoa-project.net>
Date:   Wed Sep 11 23:51:20 2019 +0200

    feat(wasmer-interface-types) Draft.

diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..0c61319
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "wasmer-interface-types"
+version = "0.6.0"
+description = "WebAssembly Interface Types library for Wasmer"
+license = "MIT"
+authors = ["The Wasmer Engineering Team <engineering@wasmer.io>"]
+repository = "https://github.com/wasmerio/wasmer"
+edition = "2018"
+
+[dependencies]
+nom = "5.0"
+
+[dev-dependencies]
+wasmer-runtime-core = { path = "../runtime-core", version = "0.6.0", features = ["backend-cranelift"] }
+wasmer-clif-backend = { path = "../clif-backend", version = "0.6.0" }
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..2ba8a8b
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,213 @@
+use nom::{
+    error::{make_error, ErrorKind, ParseError},
+    Err, IResult,
+};
+use std::{convert::TryFrom, str};
+
+macro_rules! d {
+    ($expression:expr) => {
+        match $expression {
+            tmp => {
+                eprintln!(
+                    "[{}:{}] {} = {:?}",
+                    file!(),
+                    line!(),
+                    stringify!($expression),
+                    &tmp
+                );
+
+                tmp
+            }
+        }
+    };
+}
+
+#[derive(PartialEq, Debug)]
+enum Type {
+    Int,
+    Float,
+    Any,
+    String,
+    Seq,
+
+    I32,
+    I64,
+    F32,
+    F64,
+    AnyRef,
+}
+
+#[derive(Debug)]
+struct Export<'input> {
+    name: &'input str,
+    input_types: Vec<Type>,
+    output_types: Vec<Type>,
+}
+
+impl TryFrom<u64> for Type {
+    type Error = &'static str;
+
+    fn try_from(code: u64) -> Result<Self, Self::Error> {
+        Ok(match code {
+            0x7fff => Self::Int,
+            0x7ffe => Self::Float,
+            0x7ffd => Self::Any,
+            0x7ffc => Self::String,
+            0x7ffb => Self::Seq,
+            0x7f => Self::I32,
+            0x7e => Self::I64,
+            0x7d => Self::F32,
+            0x7c => Self::F64,
+            0x6f => Self::AnyRef,
+
+            _ => return Err("Unknown type code."),
+        })
+    }
+}
+
+fn leb<'input, E: ParseError<&'input [u8]>>(input: &'input [u8]) -> IResult<&'input [u8], u64, E> {
+    if input.is_empty() {
+        return Err(Err::Error(make_error(input, ErrorKind::Eof)));
+    }
+
+    let (output, bytes) = match input.iter().position(|&byte| byte & 0x80 == 0) {
+        Some(position) => (&input[position + 1..], &input[..position + 1]),
+        None => (&[] as &[u8], input),
+    };
+
+    Ok((
+        output,
+        bytes
+            .iter()
+            .rev()
+            .fold(0, |acc, byte| (acc << 7) | (byte & 0x7f) as u64),
+    ))
+}
+
+fn string<'input, E: ParseError<&'input [u8]>>(
+    input: &'input [u8],
+) -> IResult<&'input [u8], &'input str, E> {
+    if input.is_empty() {
+        return Err(Err::Error(make_error(input, ErrorKind::Eof)));
+    }
+
+    let length = input[0] as usize;
+    let input = &input[1..];
+
+    if input.len() < length {
+        return Err(Err::Error(make_error(input, ErrorKind::Eof)));
+    }
+
+    Ok((&input[length..], unsafe {
+        str::from_utf8_unchecked(&input[..length])
+    }))
+}
+
+fn list<'input, I: ::std::fmt::Debug, E: ParseError<&'input [u8]>>(
+    input: &'input [u8],
+    item_parser: fn(&'input [u8]) -> IResult<&'input [u8], I, E>,
+) -> IResult<&'input [u8], Vec<I>, E> {
+    if input.is_empty() {
+        return Err(Err::Error(make_error(input, ErrorKind::Eof)));
+    }
+
+    let length = input[0] as usize;
+    let mut input = &input[1..];
+
+    if input.len() < length {
+        return Err(Err::Error(make_error(input, ErrorKind::Eof)));
+    }
+
+    let mut items = vec![];
+
+    for _ in 0..length {
+        let (next_input, item) = item_parser(input)?;
+        items.push(item);
+        input = next_input;
+    }
+
+    Ok((input, items))
+}
+
+fn ty<'input, E: ParseError<&'input [u8]>>(input: &'input [u8]) -> IResult<&'input [u8], Type, E> {
+    if input.is_empty() {
+        return Err(Err::Error(make_error(input, ErrorKind::Eof)));
+    }
+
+    let (input, ty) = leb(input)?;
+
+    match Type::try_from(ty) {
+        Ok(ty) => Ok((input, ty)),
+        Err(_) => Err(Err::Error(make_error(input, ErrorKind::ParseTo))),
+    }
+}
+
+pub fn parse<'input, E: ParseError<&'input [u8]>>(
+    bytes: &'input [u8],
+) -> IResult<&'input [u8], bool, E> {
+    let input = bytes;
+    let (mut input, number_of_exports) = leb(input)?;
+    d!(number_of_exports);
+
+    let mut exports = vec![];
+
+    for export_nth in 0..number_of_exports {
+        let (next_input, export_name) = string(input)?;
+        input = next_input;
+
+        let (next_input, export_input_types) = list(input, ty)?;
+        input = next_input;
+
+        let (next_input, export_output_types) = list(input, ty)?;
+        input = next_input;
+
+        exports.push(Export {
+            name: export_name,
+            input_types: export_input_types,
+            output_types: export_output_types,
+        });
+    }
+
+    d!(exports);
+
+    Ok((&[] as &[u8], true))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::parse;
+    use std::fs;
+    use wasmer_clif_backend::CraneliftCompiler;
+    use wasmer_runtime_core as runtime;
+
+    fn get_module() -> runtime::Module {
+        runtime::compile_with(
+            fs::read("tests/assets/hello_world.wasm")
+                .expect("Failed to read `tests/assets/hello_world.wasm`.")
+                .as_slice(),
+            &CraneliftCompiler::new(),
+        )
+        .expect("Failed to parse the `hello_world.wasm` module.")
+    }
+
+    #[test]
+    fn test_has_custom_section() {
+        let module = get_module();
+        let custom_section = module.info().custom_sections.get("interface-types");
+
+        assert!(custom_section.is_some());
+    }
+
+    #[test]
+    fn test_parse() {
+        let module = get_module();
+        let custom_section_bytes = module
+            .info()
+            .custom_sections
+            .get("interface-types")
+            .unwrap()
+            .as_slice();
+
+        parse::<()>(custom_section_bytes);
+    }
+}
diff --git a/tests/assets/hello_world.wasm b/tests/assets/hello_world.wasm
new file mode 100644
index 0000000..88d3c07
Binary files /dev/null and b/tests/assets/hello_world.wasm differ