398 lines
13 KiB
Rust
398 lines
13 KiB
Rust
use std::{collections::HashSet, convert::TryFrom};
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use actix_router::ResourceDef;
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use proc_macro::TokenStream;
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use proc_macro2::{Span, TokenStream as TokenStream2};
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use quote::{format_ident, quote, ToTokens, TokenStreamExt};
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use syn::{parse_macro_input, AttributeArgs, Ident, LitStr, NestedMeta};
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enum ResourceType {
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Async,
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Sync,
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}
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impl ToTokens for ResourceType {
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fn to_tokens(&self, stream: &mut TokenStream2) {
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let ident = format_ident!("to");
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stream.append(ident);
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}
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}
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macro_rules! method_type {
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(
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$($variant:ident, $upper:ident,)+
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) => {
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#[derive(Debug, PartialEq, Eq, Hash)]
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pub enum MethodType {
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$(
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$variant,
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)+
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}
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impl MethodType {
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fn as_str(&self) -> &'static str {
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match self {
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$(Self::$variant => stringify!($variant),)+
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}
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}
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fn parse(method: &str) -> Result<Self, String> {
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match method {
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$(stringify!($upper) => Ok(Self::$variant),)+
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_ => Err(format!("Unexpected HTTP method: `{}`", method)),
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}
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}
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}
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};
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}
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method_type! {
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Get, GET,
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Post, POST,
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Put, PUT,
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Delete, DELETE,
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Head, HEAD,
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Connect, CONNECT,
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Options, OPTIONS,
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Trace, TRACE,
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Patch, PATCH,
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}
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impl ToTokens for MethodType {
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fn to_tokens(&self, stream: &mut TokenStream2) {
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let ident = Ident::new(self.as_str(), Span::call_site());
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stream.append(ident);
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}
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}
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impl TryFrom<&syn::LitStr> for MethodType {
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type Error = syn::Error;
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fn try_from(value: &syn::LitStr) -> Result<Self, Self::Error> {
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Self::parse(value.value().as_str())
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.map_err(|message| syn::Error::new_spanned(value, message))
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}
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}
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struct Args {
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path: Box<dyn PathMarker>,
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resource_name: Option<syn::LitStr>,
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guards: Vec<Ident>,
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wrappers: Vec<syn::Type>,
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methods: HashSet<MethodType>,
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}
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trait PathMarker: quote::ToTokens {}
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impl PathMarker for syn::Ident {}
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impl PathMarker for syn::LitStr {}
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impl PathMarker for syn::Expr {}
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impl Args {
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fn new(args: AttributeArgs, method: Option<MethodType>) -> syn::Result<Self> {
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let mut path: Option<Box<dyn PathMarker>> = None;
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let mut resource_name = None;
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let mut guards = Vec::new();
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let mut wrappers = Vec::new();
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let mut methods = HashSet::new();
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let is_route_macro = method.is_none();
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if let Some(method) = method {
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methods.insert(method);
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}
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for arg in args {
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match arg {
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NestedMeta::Lit(syn::Lit::Str(lit)) => match path {
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None => {
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let _ = ResourceDef::new(lit.value());
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path = Some(Box::new(lit));
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}
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_ => {
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return Err(syn::Error::new_spanned(
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lit,
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"Multiple paths specified! Should be only one!",
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));
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}
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},
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NestedMeta::Meta(syn::Meta::NameValue(nv)) => {
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if nv.path.is_ident("name") {
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if let syn::Lit::Str(lit) = nv.lit {
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resource_name = Some(lit);
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} else {
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return Err(syn::Error::new_spanned(
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nv.lit,
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"Attribute name expects literal string!",
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));
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}
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} else if nv.path.is_ident("path") {
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if let syn::Lit::Str(lit) = nv.lit {
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match path {
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None => {
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path = Some(Box::new(lit.parse::<syn::Expr>()?));
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}
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_ => {
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return Err(syn::Error::new_spanned(
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lit,
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"Multiple paths specified! Should be only one!",
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));
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}
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}
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} else {
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return Err(syn::Error::new_spanned(
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nv.lit,
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"Attribute path expects literal string!",
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));
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}
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} else if nv.path.is_ident("guard") {
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if let syn::Lit::Str(lit) = nv.lit {
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guards.push(Ident::new(&lit.value(), Span::call_site()));
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} else {
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return Err(syn::Error::new_spanned(
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nv.lit,
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"Attribute guard expects literal string!",
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));
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}
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} else if nv.path.is_ident("wrap") {
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if let syn::Lit::Str(lit) = nv.lit {
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wrappers.push(lit.parse()?);
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} else {
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return Err(syn::Error::new_spanned(
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nv.lit,
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"Attribute wrap expects type",
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));
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}
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} else if nv.path.is_ident("method") {
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if !is_route_macro {
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return Err(syn::Error::new_spanned(
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&nv,
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"HTTP method forbidden here. To handle multiple methods, use `route` instead",
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));
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} else if let syn::Lit::Str(ref lit) = nv.lit {
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let method = MethodType::try_from(lit)?;
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if !methods.insert(method) {
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return Err(syn::Error::new_spanned(
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&nv.lit,
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&format!(
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"HTTP method defined more than once: `{}`",
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lit.value()
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),
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));
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}
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} else {
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return Err(syn::Error::new_spanned(
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nv.lit,
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"Attribute method expects literal string!",
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));
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}
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} else {
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return Err(syn::Error::new_spanned(
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nv.path,
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"Unknown attribute key is specified. Allowed: guard, method and wrap",
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));
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}
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}
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arg => {
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return Err(syn::Error::new_spanned(arg, "Unknown attribute."));
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}
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}
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}
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Ok(Args {
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path: path.unwrap(),
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resource_name,
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guards,
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wrappers,
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methods,
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})
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}
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}
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pub struct Route {
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name: syn::Ident,
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args: Args,
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ast: syn::ItemFn,
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resource_type: ResourceType,
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/// The doc comment attributes to copy to generated struct, if any.
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doc_attributes: Vec<syn::Attribute>,
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}
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fn guess_resource_type(typ: &syn::Type) -> ResourceType {
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let mut guess = ResourceType::Sync;
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if let syn::Type::ImplTrait(typ) = typ {
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for bound in typ.bounds.iter() {
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if let syn::TypeParamBound::Trait(bound) = bound {
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for bound in bound.path.segments.iter() {
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if bound.ident == "Future" {
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guess = ResourceType::Async;
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break;
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} else if bound.ident == "Responder" {
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guess = ResourceType::Sync;
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break;
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}
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}
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}
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}
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}
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guess
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}
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impl Route {
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pub fn new(
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args: AttributeArgs,
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ast: syn::ItemFn,
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method: Option<MethodType>,
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) -> syn::Result<Self> {
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if args.is_empty() {
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return Err(syn::Error::new(
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Span::call_site(),
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format!(
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r#"invalid service definition, expected #[{}("<some path>")]"#,
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method
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.map_or("route", |it| it.as_str())
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.to_ascii_lowercase()
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),
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));
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}
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let name = ast.sig.ident.clone();
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// Try and pull out the doc comments so that we can reapply them to the generated struct.
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// Note that multi line doc comments are converted to multiple doc attributes.
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let doc_attributes = ast
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.attrs
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.iter()
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.filter(|attr| attr.path.is_ident("doc"))
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.cloned()
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.collect();
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let args = Args::new(args, method)?;
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if args.methods.is_empty() {
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return Err(syn::Error::new(
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Span::call_site(),
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"The #[route(..)] macro requires at least one `method` attribute",
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));
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}
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let resource_type = if ast.sig.asyncness.is_some() {
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ResourceType::Async
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} else {
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match ast.sig.output {
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syn::ReturnType::Default => {
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return Err(syn::Error::new_spanned(
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ast,
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"Function has no return type. Cannot be used as handler",
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));
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}
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syn::ReturnType::Type(_, ref typ) => guess_resource_type(typ.as_ref()),
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}
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};
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Ok(Self {
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name,
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args,
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ast,
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resource_type,
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doc_attributes,
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})
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}
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}
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impl ToTokens for Route {
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fn to_tokens(&self, output: &mut TokenStream2) {
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let Self {
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name,
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ast,
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args:
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Args {
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path,
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resource_name,
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guards,
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wrappers,
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methods,
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},
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resource_type,
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doc_attributes,
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} = self;
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let resource_name = resource_name
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.as_ref()
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.map_or_else(|| name.to_string(), LitStr::value);
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let method_guards = {
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let mut others = methods.iter();
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// unwrapping since length is checked to be at least one
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let first = others.next().unwrap();
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if methods.len() > 1 {
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quote! {
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.guard(
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::actix_web::guard::Any(::actix_web::guard::#first())
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#(.or(::actix_web::guard::#others()))*
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)
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}
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} else {
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quote! {
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.guard(::actix_web::guard::#first())
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}
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}
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};
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let path = path.as_ref();
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let stream = quote! {
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#(#doc_attributes)*
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#[allow(non_camel_case_types, missing_docs)]
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pub struct #name;
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impl ::actix_web::dev::HttpServiceFactory for #name {
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fn register(self, __config: &mut actix_web::dev::AppService) {
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#ast
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let __resource = ::actix_web::Resource::new(#path)
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.name(#resource_name)
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#method_guards
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#(.guard(::actix_web::guard::fn_guard(#guards)))*
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#(.wrap(#wrappers))*
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.#resource_type(#name);
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::actix_web::dev::HttpServiceFactory::register(__resource, __config)
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}
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}
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};
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output.extend(stream);
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}
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}
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pub(crate) fn with_method(
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method: Option<MethodType>,
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args: TokenStream,
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input: TokenStream,
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) -> TokenStream {
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let args = parse_macro_input!(args as syn::AttributeArgs);
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let ast = match syn::parse::<syn::ItemFn>(input.clone()) {
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Ok(ast) => ast,
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// on parse error, make IDEs happy; see fn docs
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Err(err) => return input_and_compile_error(input, err),
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};
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match Route::new(args, ast, method) {
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Ok(route) => route.into_token_stream().into(),
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// on macro related error, make IDEs happy; see fn docs
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Err(err) => input_and_compile_error(input, err),
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}
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}
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/// Converts the error to a token stream and appends it to the original input.
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///
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/// Returning the original input in addition to the error is good for IDEs which can gracefully
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/// recover and show more precise errors within the macro body.
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///
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/// See <https://github.com/rust-analyzer/rust-analyzer/issues/10468> for more info.
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fn input_and_compile_error(mut item: TokenStream, err: syn::Error) -> TokenStream {
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let compile_err = TokenStream::from(err.to_compile_error());
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item.extend(compile_err);
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item
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}
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