progenitor/progenitor-macro/src/lib.rs

410 lines
13 KiB
Rust

// Copyright 2022 Oxide Computer Company
//! Macros for the progenitor OpenAPI client generator.
#![deny(missing_docs)]
use std::{
collections::HashMap,
fmt::Display,
fs::File,
path::{Path, PathBuf},
};
use openapiv3::OpenAPI;
use proc_macro::TokenStream;
use progenitor_impl::{
CrateVers, GenerationSettings, Generator, InterfaceStyle, TagStyle,
TypePatch, UnknownPolicy,
};
use quote::{quote, ToTokens};
use schemars::schema::SchemaObject;
use serde::Deserialize;
use serde_tokenstream::{OrderedMap, ParseWrapper};
use syn::LitStr;
use token_utils::TypeAndImpls;
mod token_utils;
/// Generates a client from the given OpenAPI document
///
/// `generate_api!` can be invoked in two ways. The simple form, takes a path
/// to the OpenAPI document:
/// ```ignore
/// generate_api!("path/to/spec.json");
/// ```
///
/// The more complex form accepts the following key-value pairs in any order:
/// ```ignore
/// generate_api!(
/// spec = "path/to/spec.json",
/// [ interface = ( Positional | Builder ), ]
/// [ tags = ( Merged | Separate ), ]
/// [ pre_hook = closure::or::path::to::function, ]
/// [ post_hook = closure::or::path::to::function, ]
///
/// [ derives = [ path::to::DeriveMacro ], ]
///
/// [ unknown_crates = (Generate | Allow | Deny ), ]
/// [ crates = { "<crate-name>" = ("<version>" | "*" | "!" ) } ]
///
/// [ patch = { TypeName = { [rename = NewTypeName], [derives = []] }, } ]
/// [ replace = { TypeName = full_path::to::other::TypeName, }]
/// [ convert = { { <schema> } = full_path::to::TypeName, }]
///
/// );
/// ```
///
/// The `spec` key is required; it is the OpenAPI document (JSON or YAML) from
/// which the client is derived.
///
/// The optional `interface` lets you specify either a `Positional` argument or
/// `Builder` argument style; `Positional` is the default.
///
/// The optional `tags` may be `Merged` in which case all operations are
/// methods on the `Client` struct or `Separate` in which case each tag is
/// represented by an "extension trait" that `Client` implements. The default
/// is `Merged`.
///
/// The optional `inner_type` is for ancillary data, stored with the generated
/// client that can be usd by the pre and post hooks.
///
/// The optional `pre_hook` is either a closure (that must be within
/// parentheses: `(fn |inner, request| { .. })`) or a path to a function. The
/// closure or function must take two parameters: the inner type and a
/// `&reqwest::Request`. This allows clients to examine requests before they're
/// sent to the server, for example to log them.
///
/// The optional `post_hook` is either a closure (that must be within
/// parentheses: `(fn |inner, result| { .. })`) or a path to a function. The
/// closure or function must take two parameters: the inner type and a
/// `&Result<reqwest::Response, reqwest::Error>`. This allows clients to
/// examine responses, for example to log them.
///
/// Additional options control type generation:
/// - `derives`: optional array of derive macro paths; the derive macros to be
/// applied to all generated types
///
/// - `struct_builder`: optional boolean; (if true) generates a `::builder()`
/// method for each generated struct that can be used to specify each
/// property and construct the struct
///
/// - `unknown_crates`: optional policy regarding the handling of schemas that
/// contain the `x-rust-type` extension whose crates are not explicitly named
/// in the `crates` section. The options are `generate` to ignore the
/// extension and generate a *de novo* type, `allow` to use the named type
/// (which may require the addition of a new dependency to compile, and which
/// ignores version compatibility checks), or `deny` to produce a
/// compile-time error (requiring the user to specify the crate's disposition
/// in the `crates` section).
///
/// - `crates`: optional map from crate name to the version of the crate in
/// use. Types encountered with the Rust type extension (`x-rust-type`) will
/// use types from the specified crates rather than generating them (within
/// the constraints of type compatibility).
///
/// - `patch`: optional map from type to an object with the optional members
/// `rename` and `derives`. This may be used to renamed generated types or
/// to apply additional (non-default) derive macros to them.
///
/// - `replace`: optional map from definition name to a replacement type. This
/// may be used to skip generation of the named type and use a existing Rust
/// type.
///
/// - `convert`: optional map from a JSON schema type defined in `$defs` to a
/// replacement type. This may be used to skip generation of the schema and
/// use an existing Rust type.
#[proc_macro]
pub fn generate_api(item: TokenStream) -> TokenStream {
match do_generate_api(item) {
Err(err) => err.to_compile_error().into(),
Ok(out) => out,
}
}
#[derive(Deserialize)]
struct MacroSettings {
spec: ParseWrapper<LitStr>,
#[serde(default)]
interface: InterfaceStyle,
#[serde(default)]
tags: TagStyle,
inner_type: Option<ParseWrapper<syn::Type>>,
pre_hook: Option<ParseWrapper<ClosureOrPath>>,
pre_hook_async: Option<ParseWrapper<ClosureOrPath>>,
post_hook: Option<ParseWrapper<ClosureOrPath>>,
#[serde(default)]
derives: Vec<ParseWrapper<syn::Path>>,
#[serde(default)]
unknown_crates: UnknownPolicy,
#[serde(default)]
crates: HashMap<CrateName, MacroCrateSpec>,
#[serde(default)]
patch: HashMap<ParseWrapper<syn::Ident>, MacroPatch>,
#[serde(default)]
replace: HashMap<ParseWrapper<syn::Ident>, ParseWrapper<TypeAndImpls>>,
#[serde(default)]
convert: OrderedMap<SchemaObject, ParseWrapper<TypeAndImpls>>,
}
#[derive(Deserialize)]
enum MacroSettingsImpl {
Display,
}
impl Display for MacroSettingsImpl {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
MacroSettingsImpl::Display => f.write_str("Display"),
}
}
}
#[derive(Deserialize)]
struct MacroPatch {
#[serde(default)]
rename: Option<String>,
#[serde(default)]
derives: Vec<ParseWrapper<syn::Path>>,
}
impl From<MacroPatch> for TypePatch {
fn from(a: MacroPatch) -> Self {
let mut s = Self::default();
a.rename.iter().for_each(|rename| {
s.with_rename(rename);
});
a.derives.iter().for_each(|derive| {
s.with_derive(derive.to_token_stream().to_string());
});
s
}
}
#[derive(Deserialize)]
enum GenerationStyle {
Positional,
Builder,
}
impl Default for GenerationStyle {
fn default() -> Self {
Self::Positional
}
}
#[derive(Debug)]
struct ClosureOrPath(proc_macro2::TokenStream);
impl syn::parse::Parse for ClosureOrPath {
fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
let lookahead = input.lookahead1();
if lookahead.peek(syn::token::Paren) {
let group: proc_macro2::Group = input.parse()?;
return syn::parse2::<Self>(group.stream());
}
if let Ok(closure) = input.parse::<syn::ExprClosure>() {
return Ok(Self(closure.to_token_stream()));
}
input
.parse::<syn::Path>()
.map(|path| Self(path.to_token_stream()))
}
}
struct MacroCrateSpec {
original: Option<String>,
version: CrateVers,
}
impl<'de> Deserialize<'de> for MacroCrateSpec {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
let ss = String::deserialize(deserializer)?;
let (original, vers_str) = if let Some(ii) = ss.find('@') {
let original_str = &ss[..ii];
let rest = &ss[ii + 1..];
if !is_crate(original_str) {
return Err(<D::Error as serde::de::Error>::invalid_value(
serde::de::Unexpected::Str(&ss),
&"valid crate name",
));
}
(Some(original_str.to_string()), rest)
} else {
(None, ss.as_ref())
};
let Some(version) = CrateVers::parse(vers_str) else {
return Err(<D::Error as serde::de::Error>::invalid_value(
serde::de::Unexpected::Str(&ss),
&"valid version",
));
};
Ok(Self { original, version })
}
}
#[derive(Hash, PartialEq, Eq)]
struct CrateName(String);
impl<'de> Deserialize<'de> for CrateName {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
let ss = String::deserialize(deserializer)?;
if is_crate(&ss) {
Ok(Self(ss))
} else {
Err(<D::Error as serde::de::Error>::invalid_value(
serde::de::Unexpected::Str(&ss),
&"valid crate name",
))
}
}
}
fn is_crate(s: &str) -> bool {
!s.contains(|cc: char| !cc.is_alphanumeric() && cc != '_' && cc != '-')
}
fn open_file(
path: PathBuf,
span: proc_macro2::Span,
) -> Result<File, syn::Error> {
File::open(path.clone()).map_err(|e| {
let path_str = path.to_string_lossy();
syn::Error::new(span, format!("couldn't read file {}: {}", path_str, e))
})
}
fn do_generate_api(item: TokenStream) -> Result<TokenStream, syn::Error> {
let (spec, settings) = if let Ok(spec) = syn::parse::<LitStr>(item.clone())
{
(spec, GenerationSettings::default())
} else {
let MacroSettings {
spec,
interface,
tags,
inner_type,
pre_hook,
pre_hook_async,
post_hook,
unknown_crates,
crates,
derives,
patch,
replace,
convert,
} = serde_tokenstream::from_tokenstream(&item.into())?;
let mut settings = GenerationSettings::default();
settings.with_interface(interface);
settings.with_tag(tags);
inner_type.map(|inner_type| {
settings.with_inner_type(inner_type.to_token_stream())
});
pre_hook
.map(|pre_hook| settings.with_pre_hook(pre_hook.into_inner().0));
pre_hook_async.map(|pre_hook_async| {
settings.with_pre_hook_async(pre_hook_async.into_inner().0)
});
post_hook
.map(|post_hook| settings.with_post_hook(post_hook.into_inner().0));
settings.with_unknown_crates(unknown_crates);
crates.into_iter().for_each(
|(CrateName(crate_name), MacroCrateSpec { original, version })| {
if let Some(original_crate) = original {
settings.with_crate(
original_crate,
version,
Some(&crate_name),
);
} else {
settings.with_crate(crate_name, version, None);
}
},
);
derives.into_iter().for_each(|derive| {
settings.with_derive(derive.to_token_stream());
});
patch.into_iter().for_each(|(type_name, patch)| {
settings.with_patch(
type_name.to_token_stream().to_string(),
&patch.into(),
);
});
replace.into_iter().for_each(|(type_name, type_and_impls)| {
let type_name = type_name.to_token_stream();
let (replace_name, impls) =
type_and_impls.into_inner().into_name_and_impls();
settings.with_replacement(type_name, replace_name, impls);
});
convert.into_iter().for_each(|(schema, type_and_impls)| {
let (type_name, impls) =
type_and_impls.into_inner().into_name_and_impls();
settings.with_conversion(schema, type_name, impls);
});
(spec.into_inner(), settings)
};
let dir = std::env::var("CARGO_MANIFEST_DIR").map_or_else(
|_| std::env::current_dir().unwrap(),
|s| Path::new(&s).to_path_buf(),
);
let path = dir.join(spec.value());
let path_str = path.to_string_lossy();
let mut f = open_file(path.clone(), spec.span())?;
let oapi: OpenAPI = match serde_json::from_reader(f) {
Ok(json_value) => json_value,
_ => {
f = open_file(path.clone(), spec.span())?;
serde_yaml::from_reader(f).map_err(|e| {
syn::Error::new(
spec.span(),
format!("failed to parse {}: {}", path_str, e),
)
})?
}
};
let mut builder = Generator::new(&settings);
let code = builder.generate_tokens(&oapi).map_err(|e| {
syn::Error::new(
spec.span(),
format!("generation error for {}: {}", spec.value(), e),
)
})?;
let output = quote! {
// The progenitor_client is tautologically visible from macro
// consumers.
use progenitor::progenitor_client;
#code
// Force a rebuild when the given file is modified.
const _: &str = include_str!(#path_str);
};
Ok(output.into())
}