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feat(interface-types) Add the binary encoder #1216

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354 changes: 354 additions & 0 deletions lib/interface-types/src/encoders/binary.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,354 @@
//! Writes the AST into bytes representing WIT with its binary format.
use crate::{
ast::{Adapter, AdapterKind, Export, Import, InterfaceType, Interfaces, Type},
interpreter::Instruction,
};
use std::io::{self, Write};

/// A trait for converting a value to bytes.
trait ToBytes<W>
where
W: Write,
{
/// Converts the given value into `&[u8]` in the given `writer`.
fn to_bytes(&self, writer: &mut W) -> io::Result<()>;
}

/// Encode a `u8` into a byte (well, it's already a byte!).
impl<W> ToBytes<W> for u8
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
writer.write_all(&[*self])
}
}

/// Encode a `u64` into bytes with a LEB128 representation.
///
/// Decoder is `decoders::binary::uleb`.
impl<W> ToBytes<W> for u64
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
let mut value = *self;

// Code adapted from the Rust' `serialize` library.
loop {
if value < 0x80 {
writer.write_all(&[value as u8])?;

break;
}

writer.write_all(&[((value & 0x7f) | 0x80) as u8])?;
value >>= 7;
}

Ok(())
}
}

/// Encode a `str` into bytes.
///
/// Decoder is `decoders::binary::string`.
impl<W> ToBytes<W> for &str
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
// Size first.
writer.write_all(&[self.len() as u8])?;

// Then the string.
writer.write_all(self.as_bytes())?;

Ok(())
}
}

/// Encode a vector into bytes.
///
/// Decoder is `decoders::binary::list`.
impl<W, I> ToBytes<W> for Vec<I>
where
W: Write,
I: ToBytes<W>,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
// Size first.
(self.len() as u64).to_bytes(writer)?;

// Then the items.
for item in self {
item.to_bytes(writer)?;
}

Ok(())
}
}

/// Encode an `InterfaceType` into bytes.
impl<W> ToBytes<W> for InterfaceType
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
match self {
InterfaceType::Int => 0x7fff_u64.to_bytes(writer),
InterfaceType::Float => 0x7ffe_u64.to_bytes(writer),
InterfaceType::Any => 0x7ffd_u64.to_bytes(writer),
InterfaceType::String => 0x7ffc_u64.to_bytes(writer),
InterfaceType::Seq => 0x7ffb_u64.to_bytes(writer),
InterfaceType::I32 => 0x7f_u64.to_bytes(writer),
InterfaceType::I64 => 0x7e_u64.to_bytes(writer),
InterfaceType::F32 => 0x7d_u64.to_bytes(writer),
InterfaceType::F64 => 0x7d_u64.to_bytes(writer),
InterfaceType::AnyRef => 0x6f_u64.to_bytes(writer),
}
}
}

/// Encode an `AdapterKind` into bytes.
impl<W> ToBytes<W> for AdapterKind
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
match self {
AdapterKind::Import => 0x00_u8.to_bytes(writer),
AdapterKind::Export => 0x01_u8.to_bytes(writer),
AdapterKind::HelperFunction => 0x02_u8.to_bytes(writer),
}
}
}

/// Encode an `Export` into bytes.
///
/// Decoder is in `decoders::binary::exports`.
impl<W> ToBytes<W> for Export<'_>
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
self.name.to_bytes(writer)?;
self.input_types.to_bytes(writer)?;
self.output_types.to_bytes(writer)?;

Ok(())
}
}

/// Encode a `Type` into bytes.
///
/// Decoder is in `decoders::binary::types`.
impl<W> ToBytes<W> for Type<'_>
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
self.name.to_bytes(writer)?;
self.field_names().to_bytes(writer)?;
self.field_types().to_bytes(writer)?;

Ok(())
}
}

/// Encode an `Import` into bytes.
///
/// Decoder is in `decoders::binary::imports`.
impl<W> ToBytes<W> for Import<'_>
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
self.namespace.to_bytes(writer)?;
self.name.to_bytes(writer)?;
self.input_types.to_bytes(writer)?;
self.output_types.to_bytes(writer)?;

Ok(())
}
}

/// Encode an `Adapter` into bytes.
///
/// Decoder is in `decoders::binary::imports`.
impl<W> ToBytes<W> for Adapter<'_>
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
match self {
Adapter::Import {
namespace,
name,
input_types,
output_types,
instructions,
} => {
AdapterKind::Import.to_bytes(writer)?;
namespace.to_bytes(writer)?;
name.to_bytes(writer)?;
input_types.to_bytes(writer)?;
output_types.to_bytes(writer)?;
instructions.to_bytes(writer)?;
}

Adapter::Export {
name,
input_types,
output_types,
instructions,
} => {
AdapterKind::Export.to_bytes(writer)?;
name.to_bytes(writer)?;
input_types.to_bytes(writer)?;
output_types.to_bytes(writer)?;
instructions.to_bytes(writer)?;
}

Adapter::HelperFunction {
name,
input_types,
output_types,
instructions,
} => {
AdapterKind::HelperFunction.to_bytes(writer)?;
name.to_bytes(writer)?;
input_types.to_bytes(writer)?;
output_types.to_bytes(writer)?;
instructions.to_bytes(writer)?;
}
}

Ok(())
}
}

/// Encode an `Interfaces` into bytes.
///
/// Decoder is `decoders::binary::parse`.
impl<W> ToBytes<W> for Interfaces<'_>
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
self.exports.to_bytes(writer)?;
self.types.to_bytes(writer)?;
self.imports.to_bytes(writer)?;
self.adapters.to_bytes(writer)?;

Ok(())
}
}

/// Encode an `Instruction` into bytes.
///
/// Decoder is `decoders::binary::instruction`.
impl<W> ToBytes<W> for Instruction<'_>
where
W: Write,
{
fn to_bytes(&self, writer: &mut W) -> io::Result<()> {
match self {
Instruction::ArgumentGet { index } => {
0x00_u8.to_bytes(writer)?;
index.to_bytes(writer)?;
}

Instruction::Call { function_index } => {
0x01_u8.to_bytes(writer)?;
(*function_index as u64).to_bytes(writer)?;
}

Instruction::CallExport { export_name } => {
0x02_u8.to_bytes(writer)?;
export_name.to_bytes(writer)?;
}

Instruction::ReadUtf8 => 0x03_u8.to_bytes(writer)?,

Instruction::WriteUtf8 { allocator_name } => {
0x04_u8.to_bytes(writer)?;
allocator_name.to_bytes(writer)?;
}

Instruction::AsWasm(interface_type) => {
0x05_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
}

Instruction::AsInterface(interface_type) => {
0x06_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
}

Instruction::TableRefAdd => 0x07_u8.to_bytes(writer)?,

Instruction::TableRefGet => 0x08_u8.to_bytes(writer)?,

Instruction::CallMethod(function_index) => {
0x09_u8.to_bytes(writer)?;
function_index.to_bytes(writer)?;
}

Instruction::MakeRecord(interface_type) => {
0x0a_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
}

Instruction::GetField(interface_type, field_index) => {
0x0c_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
field_index.to_bytes(writer)?;
}

Instruction::Const(interface_type, index) => {
0x0d_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
index.to_bytes(writer)?;
}

Instruction::FoldSeq(index) => {
0x0e_u8.to_bytes(writer)?;
index.to_bytes(writer)?;
}

Instruction::Add(interface_type) => {
0x0f_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
}

Instruction::MemToSeq(interface_type, string) => {
0x10_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
string.to_bytes(writer)?;
}

Instruction::Load(interface_type, string) => {
0x11_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
string.to_bytes(writer)?;
}

Instruction::SeqNew(interface_type) => {
0x12_u8.to_bytes(writer)?;
interface_type.to_bytes(writer)?;
}

Instruction::ListPush => 0x13_u8.to_bytes(writer)?,

Instruction::RepeatUntil(index1, index2) => {
0x14_u8.to_bytes(writer)?;
index1.to_bytes(writer)?;
index2.to_bytes(writer)?;
}
}

Ok(())
}
}
1 change: 1 addition & 0 deletions lib/interface-types/src/encoders/mod.rs
Original file line number Diff line number Diff line change
@@ -2,4 +2,5 @@
//! `encoders::wat` writes the AST into a string representing WIT with
//! its textual format.
pub mod binary;
pub mod wat;