Files
wasmtime/crates/wiggle/generate/src/config.rs
2020-06-03 10:53:55 -07:00

305 lines
8.5 KiB
Rust

use {
proc_macro2::Span,
std::{
collections::HashMap,
iter::FromIterator,
path::{Path, PathBuf},
},
syn::{
braced, bracketed,
parse::{Parse, ParseStream},
punctuated::Punctuated,
Error, Ident, LitStr, Result, Token,
},
};
#[derive(Debug, Clone)]
pub struct Config {
pub witx: WitxConf,
pub ctx: CtxConf,
pub errors: ErrorConf,
}
#[derive(Debug, Clone)]
pub enum ConfigField {
Witx(WitxConf),
Ctx(CtxConf),
Error(ErrorConf),
}
mod kw {
syn::custom_keyword!(witx);
syn::custom_keyword!(witx_literal);
syn::custom_keyword!(ctx);
syn::custom_keyword!(errors);
}
impl Parse for ConfigField {
fn parse(input: ParseStream) -> Result<Self> {
let lookahead = input.lookahead1();
if lookahead.peek(kw::witx) {
input.parse::<kw::witx>()?;
input.parse::<Token![:]>()?;
Ok(ConfigField::Witx(WitxConf::Paths(input.parse()?)))
} else if lookahead.peek(kw::witx_literal) {
input.parse::<kw::witx_literal>()?;
input.parse::<Token![:]>()?;
Ok(ConfigField::Witx(WitxConf::Literal(input.parse()?)))
} else if lookahead.peek(kw::ctx) {
input.parse::<kw::ctx>()?;
input.parse::<Token![:]>()?;
Ok(ConfigField::Ctx(input.parse()?))
} else if lookahead.peek(kw::errors) {
input.parse::<kw::errors>()?;
input.parse::<Token![:]>()?;
Ok(ConfigField::Error(input.parse()?))
} else {
Err(lookahead.error())
}
}
}
impl Config {
pub fn build(fields: impl Iterator<Item = ConfigField>, err_loc: Span) -> Result<Self> {
let mut witx = None;
let mut ctx = None;
let mut errors = None;
for f in fields {
match f {
ConfigField::Witx(c) => {
if witx.is_some() {
return Err(Error::new(err_loc, "duplicate `witx` field"));
}
witx = Some(c);
}
ConfigField::Ctx(c) => {
if ctx.is_some() {
return Err(Error::new(err_loc, "duplicate `ctx` field"));
}
ctx = Some(c);
}
ConfigField::Error(c) => {
if errors.is_some() {
return Err(Error::new(err_loc, "duplicate `errors` field"));
}
errors = Some(c);
}
}
}
Ok(Config {
witx: witx
.take()
.ok_or_else(|| Error::new(err_loc, "`witx` field required"))?,
ctx: ctx
.take()
.ok_or_else(|| Error::new(err_loc, "`ctx` field required"))?,
errors: errors.take().unwrap_or_default(),
})
}
/// Load the `witx` document for the configuration.
///
/// # Panics
///
/// This method will panic if the paths given in the `witx` field were not valid documents.
pub fn load_document(&self) -> witx::Document {
self.witx.load_document()
}
}
impl Parse for Config {
fn parse(input: ParseStream) -> Result<Self> {
let contents;
let _lbrace = braced!(contents in input);
let fields: Punctuated<ConfigField, Token![,]> =
contents.parse_terminated(ConfigField::parse)?;
Ok(Config::build(fields.into_iter(), input.span())?)
}
}
/// The witx document(s) that will be loaded from a [`Config`](struct.Config.html).
///
/// A witx interface definition can be provided either as a collection of relative paths to
/// documents, or as a single inlined string literal. Note that `(use ...)` directives are not
/// permitted when providing a string literal.
#[derive(Debug, Clone)]
pub enum WitxConf {
/// A collection of paths pointing to witx files.
Paths(Paths),
/// A single witx document, provided as a string literal.
Literal(Literal),
}
impl WitxConf {
/// Load the `witx` document.
///
/// # Panics
///
/// This method will panic if the paths given in the `witx` field were not valid documents, or
/// if any of the given documents were not syntactically valid.
pub fn load_document(&self) -> witx::Document {
match self {
Self::Paths(paths) => witx::load(paths.as_ref()).expect("loading witx"),
Self::Literal(doc) => witx::parse(doc.as_ref()).expect("parsing witx"),
}
}
/// If using the [`Paths`][paths] syntax, make all paths relative to a root directory.
///
/// [paths]: enum.WitxConf.html#variant.Paths
pub fn make_paths_relative_to<P: AsRef<Path>>(&mut self, root: P) {
if let Self::Paths(paths) = self {
paths.as_mut().iter_mut().for_each(|p| {
if !p.is_absolute() {
*p = PathBuf::from(root.as_ref()).join(p.clone());
}
});
}
}
}
/// A collection of paths, pointing to witx documents.
#[derive(Debug, Clone)]
pub struct Paths(Vec<PathBuf>);
impl Paths {
/// Create a new, empty collection of paths.
pub fn new() -> Self {
Default::default()
}
}
impl Default for Paths {
fn default() -> Self {
Self(Default::default())
}
}
impl AsRef<[PathBuf]> for Paths {
fn as_ref(&self) -> &[PathBuf] {
self.0.as_ref()
}
}
impl AsMut<[PathBuf]> for Paths {
fn as_mut(&mut self) -> &mut [PathBuf] {
self.0.as_mut()
}
}
impl FromIterator<PathBuf> for Paths {
fn from_iter<I>(iter: I) -> Self
where
I: IntoIterator<Item = PathBuf>,
{
Self(iter.into_iter().collect())
}
}
impl Parse for Paths {
fn parse(input: ParseStream) -> Result<Self> {
let content;
let _ = bracketed!(content in input);
let path_lits: Punctuated<LitStr, Token![,]> = content.parse_terminated(Parse::parse)?;
Ok(path_lits
.iter()
.map(|lit| PathBuf::from(lit.value()))
.collect())
}
}
/// A single witx document, provided as a string literal.
#[derive(Debug, Clone)]
pub struct Literal(String);
impl AsRef<str> for Literal {
fn as_ref(&self) -> &str {
self.0.as_ref()
}
}
impl Parse for Literal {
fn parse(input: ParseStream) -> Result<Self> {
Ok(Self(input.parse::<syn::LitStr>()?.value()))
}
}
#[derive(Debug, Clone)]
pub struct CtxConf {
pub name: Ident,
}
impl Parse for CtxConf {
fn parse(input: ParseStream) -> Result<Self> {
Ok(CtxConf {
name: input.parse()?,
})
}
}
#[derive(Clone, Default, Debug)]
/// Map from abi error type to rich error type
pub struct ErrorConf(HashMap<Ident, ErrorConfField>);
impl ErrorConf {
pub fn iter(&self) -> impl Iterator<Item = (&Ident, &ErrorConfField)> {
self.0.iter()
}
}
impl Parse for ErrorConf {
fn parse(input: ParseStream) -> Result<Self> {
let content;
let _ = braced!(content in input);
let items: Punctuated<ErrorConfField, Token![,]> =
content.parse_terminated(Parse::parse)?;
let mut m = HashMap::new();
for i in items {
match m.insert(i.abi_error.clone(), i.clone()) {
None => {}
Some(prev_def) => {
return Err(Error::new(
i.err_loc,
format!(
"duplicate definition of rich error type for {:?}: previously defined at {:?}",
i.abi_error, prev_def.err_loc,
),
))
}
}
}
Ok(ErrorConf(m))
}
}
#[derive(Clone)]
pub struct ErrorConfField {
pub abi_error: Ident,
pub rich_error: syn::Path,
pub err_loc: Span,
}
impl std::fmt::Debug for ErrorConfField {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("ErrorConfField")
.field("abi_error", &self.abi_error)
.field("rich_error", &"(...)")
.field("err_loc", &self.err_loc)
.finish()
}
}
impl Parse for ErrorConfField {
fn parse(input: ParseStream) -> Result<Self> {
let err_loc = input.span();
let abi_error = input.parse::<Ident>()?;
let _arrow: Token![=>] = input.parse()?;
let rich_error = input.parse::<syn::Path>()?;
Ok(ErrorConfField {
abi_error,
rich_error,
err_loc,
})
}
}