Add a wit-encoder tool (#1580)

* init wit-encoder

* implement base types for `wit-encoder`

* fix warnings

* tidy up

* tidy world

* Mostly interface updates

* Interface updates

* Function accessors

* Result accessors

* Some type updates

* impl Display for inline types

* Some type additions

* Added render trait

* TypeDef flags, enums, and variants

* params construct from iterator

* Added resource

* Standalone functions

* Removed some unused types

* Added some tests

* Docs

* Handle intensifiers with keywords

* Cleaned up some comments

* Clean up render a bit

* Made some things more private

* Some smaller usability changes

* Added serde dependency

* Same derives everywhere

* interface and package items should be a single Vec, to keep global order

* Cargo.lock

* Fix up world

* Fix type

* Renamed StandaloneFunction to StandaloneFunc

* Revert formatting of items outside of wit-encoder

* Removed serde

* Not all types can be borrowed

* Some small result related improvements

* Added wit-encoder to workspace properly

* Updated Cargo.lock

* Added wit-encoder to publish list

---------

Co-authored-by: Yosh <github@yosh.is>

Cargo.toml

@@ -37,6 +37,7 @@ members = [
   'crates/fuzz-stats',
   'crates/wasm-mutate-stats',
   'fuzz',
+  'crates/wit-encoder',
   'crates/wit-parser/fuzz',
   'crates/wit-component/dl',
   'playground/component',
@@ -94,6 +95,7 @@ wasmprinter = { version = "0.210.0", path = "crates/wasmprinter" }
 wast = { version = "210.0.0", path = "crates/wast" }
 wat = { version = "1.210.0", path = "crates/wat" }
 wit-component = { version = "0.210.0", path = "crates/wit-component" }
+wit-encoder = { version = "0.210.0", path = "crates/wit-encoder" }
 wit-parser = { version = "0.210.0", path = "crates/wit-parser" }
 wit-smith = { version = "0.210.0", path = "crates/wit-smith" }
 
@@ -140,6 +142,7 @@ cpp_demangle = { version = "0.4.0", optional = true }
 
 # Dependencies of `component`
 wit-component = { workspace = true, optional = true, features = ['dummy-module', 'wat', 'semver-check'] }
+wit-encoder = { workspace = true, optional = true }
 wit-parser = { workspace = true, optional = true, features = ['decoding', 'wat', 'serde'] }
 wast = { workspace = true, optional = true }
 
@@ -208,6 +211,7 @@ compose = ['wasm-compose', 'dep:wasmparser']
 demangle = ['rustc-demangle', 'cpp_demangle', 'dep:wasmparser', 'wasm-encoder']
 component = [
   'wit-component',
+  'wit-encoder',
   'wit-parser',
   'dep:wast',
   'wasm-encoder',

ci/publish.rs

@@ -28,6 +28,7 @@ const CRATES_TO_PUBLISH: &[&str] = &[
     "wit-parser",
     "wasm-metadata",
     "wit-component",
+    "wit-encoder",
     "wasm-compose",
     "wit-smith",
     "wasm-tools",

crates/wit-encoder/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+description = "A WIT encoder for Rust"
+documentation = "https://docs.rs/wit-encoder"
+edition.workspace = true
+license = "Apache-2.0 WITH LLVM-exception"
+name = "wit-encoder"
+repository = "https://github.com/bytecodealliance/wasm-tools/tree/main/crates/wit-encoder"
+version.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]
+semver = { workspace = true }
+pretty_assertions = { workspace = true }

crates/wit-encoder/src/docs.rs

@@ -0,0 +1,37 @@
+use std::fmt;
+
+use crate::{Render, RenderOpts};
+
+/// Documentation
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+pub struct Docs {
+    contents: String,
+}
+
+impl Docs {
+    pub fn new(contents: impl Into<String>) -> Self {
+        Self {
+            contents: contents.into(),
+        }
+    }
+}
+
+impl<S> From<S> for Docs
+where
+    S: Into<String>,
+{
+    fn from(value: S) -> Self {
+        Self {
+            contents: value.into(),
+        }
+    }
+}
+
+impl Render for Docs {
+    fn render(&self, f: &mut fmt::Formatter<'_>, opts: &RenderOpts) -> fmt::Result {
+        for line in self.contents.lines() {
+            write!(f, "{}/// {}\n", opts.spaces(), line)?;
+        }
+        Ok(())
+    }
+}

crates/wit-encoder/src/enum_.rs

@@ -0,0 +1,59 @@
+use crate::{Docs, Ident};
+
+/// A variant without a payload
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+pub struct Enum {
+    pub(crate) cases: Vec<EnumCase>,
+}
+
+impl<C> FromIterator<C> for Enum
+where
+    C: Into<EnumCase>,
+{
+    fn from_iter<T: IntoIterator<Item = C>>(iter: T) -> Self {
+        Self {
+            cases: iter.into_iter().map(|c| c.into()).collect(),
+        }
+    }
+}
+
+impl Enum {
+    pub fn cases(&self) -> &[EnumCase] {
+        &self.cases
+    }
+
+    pub fn cases_mut(&mut self) -> &mut Vec<EnumCase> {
+        &mut self.cases
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct EnumCase {
+    pub(crate) name: Ident,
+    pub(crate) docs: Option<Docs>,
+}
+
+impl<N> From<N> for EnumCase
+where
+    N: Into<Ident>,
+{
+    fn from(value: N) -> Self {
+        Self {
+            name: value.into(),
+            docs: None,
+        }
+    }
+}
+
+impl EnumCase {
+    pub fn new(name: impl Into<Ident>) -> Self {
+        Self {
+            name: name.into(),
+            docs: None,
+        }
+    }
+
+    pub fn docs(&mut self, docs: Option<impl Into<Docs>>) {
+        self.docs = docs.map(|d| d.into());
+    }
+}

crates/wit-encoder/src/flags.rs

@@ -0,0 +1,62 @@
+use crate::{ident::Ident, Docs};
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Flags {
+    pub(crate) flags: Vec<Flag>,
+}
+
+impl Flags {
+    pub fn new(flags: impl IntoIterator<Item = impl Into<Flag>>) -> Self {
+        Self {
+            flags: flags.into_iter().map(|f| f.into()).collect(),
+        }
+    }
+
+    pub fn flags(&self) -> &[Flag] {
+        &self.flags
+    }
+
+    pub fn flags_mut(&mut self) -> &mut Vec<Flag> {
+        &mut self.flags
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Flag {
+    pub(crate) name: Ident,
+    pub(crate) docs: Option<Docs>,
+}
+
+impl Flag {
+    pub fn new(name: impl Into<Ident>) -> Self {
+        Flag {
+            name: name.into(),
+            docs: None,
+        }
+    }
+
+    pub fn docs(&mut self, docs: Option<impl Into<Docs>>) {
+        self.docs = docs.map(|d| d.into());
+    }
+}
+
+impl<T> Into<Flag> for (T,)
+where
+    T: Into<Ident>,
+{
+    fn into(self) -> Flag {
+        Flag::new(self.0)
+    }
+}
+
+impl<T, D> Into<Flag> for (T, D)
+where
+    T: Into<Ident>,
+    D: Into<Docs>,
+{
+    fn into(self) -> Flag {
+        let mut flag = Flag::new(self.0);
+        flag.docs(Some(self.1));
+        flag
+    }
+}