Jonas Platte fdd326edf7
Move Outgoing from ruma-api to ruma-common
The derive macro moves from ruma-api-macros to a new ruma-common-macros
crate likewise.
2020-09-22 21:35:10 +02:00

515 lines
17 KiB
Rust

//! Details of the `ruma_api` procedural macro.
use std::convert::{TryFrom, TryInto as _};
use proc_macro2::TokenStream;
use quote::{quote, ToTokens};
use syn::{
braced,
parse::{Parse, ParseStream},
spanned::Spanned,
Attribute, Field, FieldValue, Token, Type,
};
pub(crate) mod attribute;
pub(crate) mod metadata;
pub(crate) mod request;
pub(crate) mod response;
use self::{metadata::Metadata, request::Request, response::Response};
use crate::util;
/// Removes `serde` attributes from struct fields.
pub fn strip_serde_attrs(field: &Field) -> Field {
let mut field = field.clone();
field.attrs.retain(|attr| !attr.path.is_ident("serde"));
field
}
/// The result of processing the `ruma_api` macro, ready for output back to source code.
pub struct Api {
/// The `metadata` section of the macro.
metadata: Metadata,
/// The `request` section of the macro.
request: Request,
/// The `response` section of the macro.
response: Response,
/// The `error` section of the macro.
error: TokenStream,
}
impl TryFrom<RawApi> for Api {
type Error = syn::Error;
fn try_from(raw_api: RawApi) -> syn::Result<Self> {
let import_path = util::import_ruma_api();
let res = Self {
metadata: raw_api.metadata.try_into()?,
request: raw_api.request.try_into()?,
response: raw_api.response.try_into()?,
error: match raw_api.error {
Some(raw_err) => raw_err.ty.to_token_stream(),
None => quote! { #import_path::error::Void },
},
};
let newtype_body_field = res.request.newtype_body_field();
if res.metadata.method == "GET"
&& (res.request.has_body_fields() || newtype_body_field.is_some())
{
let mut combined_error: Option<syn::Error> = None;
let mut add_error = |field| {
let error = syn::Error::new_spanned(field, "GET endpoints can't have body fields");
if let Some(combined_error_ref) = &mut combined_error {
combined_error_ref.combine(error);
} else {
combined_error = Some(error);
}
};
for field in res.request.body_fields() {
add_error(field);
}
if let Some(field) = newtype_body_field {
add_error(field);
}
Err(combined_error.unwrap())
} else {
Ok(res)
}
}
}
impl ToTokens for Api {
fn to_tokens(&self, tokens: &mut TokenStream) {
// Guarantee `ruma_api` is available and named something we can refer to.
let ruma_api_import = util::import_ruma_api();
let description = &self.metadata.description;
let method = &self.metadata.method;
// We don't (currently) use this literal as a literal in the generated code. Instead we just
// put it into doc comments, for which the span information is irrelevant. So we can work
// with only the literal's value from here on.
let name = &self.metadata.name.value();
let path = &self.metadata.path;
let rate_limited = &self.metadata.rate_limited;
let authentication = &self.metadata.authentication;
let request_type = &self.request;
let response_type = &self.response;
let incoming_request_type = if self.request.contains_lifetimes() {
quote!(IncomingRequest)
} else {
quote!(Request)
};
let extract_request_path = if self.request.has_path_fields() {
quote! {
let path_segments: ::std::vec::Vec<&::std::primitive::str> =
request.uri().path()[1..].split('/').collect();
}
} else {
TokenStream::new()
};
let (request_path_string, parse_request_path) =
util::request_path_string_and_parse(&self.request, &self.metadata, &ruma_api_import);
let request_query_string = util::build_query_string(&self.request, &ruma_api_import);
let extract_request_query = util::extract_request_query(&self.request, &ruma_api_import);
let parse_request_query = if let Some(field) = self.request.query_map_field() {
let field_name = field.ident.as_ref().expect("expected field to have an identifier");
quote! {
#field_name: request_query,
}
} else {
self.request.request_init_query_fields()
};
let mut header_kvs = self.request.append_header_kvs();
if authentication == "AccessToken" {
header_kvs.extend(quote! {
req_builder = req_builder.header(
#ruma_api_import::exports::http::header::AUTHORIZATION,
#ruma_api_import::exports::http::header::HeaderValue::from_str(
&::std::format!(
"Bearer {}",
access_token.ok_or(
#ruma_api_import::error::IntoHttpError::NeedsAuthentication
)?
)
)?
);
});
}
let extract_request_headers = if self.request.has_header_fields() {
quote! {
let headers = request.headers();
}
} else {
TokenStream::new()
};
let extract_request_body = if self.request.has_body_fields()
|| self.request.newtype_body_field().is_some()
{
let body_lifetimes = if self.request.has_body_lifetimes() {
// duplicate the anonymous lifetime as many times as needed
let lifetimes =
std::iter::repeat(quote! { '_ }).take(self.request.body_lifetime_count());
quote! { < #( #lifetimes, )* >}
} else {
TokenStream::new()
};
quote! {
let request_body: <
RequestBody #body_lifetimes
as #ruma_api_import::exports::ruma_common::Outgoing
>::Incoming =
#ruma_api_import::try_deserialize!(
request,
#ruma_api_import::exports::serde_json::from_slice(request.body().as_slice())
);
}
} else {
TokenStream::new()
};
let parse_request_headers = if self.request.has_header_fields() {
self.request.parse_headers_from_request()
} else {
TokenStream::new()
};
let request_body = util::build_request_body(&self.request, &ruma_api_import);
let parse_request_body = util::parse_request_body(&self.request);
let extract_response_headers = if self.response.has_header_fields() {
quote! {
let mut headers = response.headers().clone();
}
} else {
TokenStream::new()
};
let typed_response_body_decl = if self.response.has_body_fields()
|| self.response.newtype_body_field().is_some()
{
quote! {
let response_body: <
ResponseBody
as #ruma_api_import::exports::ruma_common::Outgoing
>::Incoming =
#ruma_api_import::try_deserialize!(
response,
#ruma_api_import::exports::serde_json::from_slice(response.body().as_slice()),
);
}
} else {
TokenStream::new()
};
let response_init_fields = self.response.init_fields();
let serialize_response_headers = self.response.apply_header_fields();
let body = self.response.to_body();
let metadata_doc = format!("Metadata for the `{}` API endpoint.", name);
let request_doc = format!(
"Data for a request to the `{}` API endpoint.\n\n{}",
name,
description.value()
);
let response_doc = format!("Data in the response from the `{}` API endpoint.", name);
let error = &self.error;
let request_lifetimes = self.request.combine_lifetimes();
let non_auth_endpoint_impls = if authentication != "None" {
TokenStream::new()
} else {
quote! {
impl #request_lifetimes #ruma_api_import::OutgoingNonAuthRequest
for Request #request_lifetimes
{}
impl #ruma_api_import::IncomingNonAuthRequest for #incoming_request_type {}
}
};
let api = quote! {
#[doc = #request_doc]
#request_type
impl ::std::convert::TryFrom<#ruma_api_import::exports::http::Request<Vec<u8>>>
for #incoming_request_type
{
type Error = #ruma_api_import::error::FromHttpRequestError;
#[allow(unused_variables)]
fn try_from(
request: #ruma_api_import::exports::http::Request<Vec<u8>>
) -> ::std::result::Result<Self, Self::Error> {
#extract_request_path
#extract_request_query
#extract_request_headers
#extract_request_body
Ok(Self {
#parse_request_path
#parse_request_query
#parse_request_headers
#parse_request_body
})
}
}
#[doc = #response_doc]
#response_type
impl ::std::convert::TryFrom<Response> for #ruma_api_import::exports::http::Response<Vec<u8>> {
type Error = #ruma_api_import::error::IntoHttpError;
#[allow(unused_variables)]
fn try_from(response: Response) -> ::std::result::Result<Self, Self::Error> {
let mut resp_builder = #ruma_api_import::exports::http::Response::builder()
.header(#ruma_api_import::exports::http::header::CONTENT_TYPE, "application/json");
#serialize_response_headers
// Since we require header names to come from the `http::header` module,
// this cannot fail.
let response = resp_builder.body(#body).unwrap();
Ok(response)
}
}
impl ::std::convert::TryFrom<#ruma_api_import::exports::http::Response<Vec<u8>>> for Response {
type Error = #ruma_api_import::error::FromHttpResponseError<#error>;
#[allow(unused_variables)]
fn try_from(
response: #ruma_api_import::exports::http::Response<Vec<u8>>,
) -> ::std::result::Result<Self, Self::Error> {
if response.status().as_u16() < 400 {
#extract_response_headers
#typed_response_body_decl
Ok(Self {
#response_init_fields
})
} else {
match <#error as #ruma_api_import::EndpointError>::try_from_response(response) {
Ok(err) => Err(#ruma_api_import::error::ServerError::Known(err).into()),
Err(response_err) => {
Err(#ruma_api_import::error::ServerError::Unknown(response_err).into())
}
}
}
}
}
const __METADATA: #ruma_api_import::Metadata = #ruma_api_import::Metadata {
description: #description,
method: #ruma_api_import::exports::http::Method::#method,
name: #name,
path: #path,
rate_limited: #rate_limited,
authentication: #ruma_api_import::AuthScheme::#authentication,
};
impl #request_lifetimes #ruma_api_import::OutgoingRequest
for Request #request_lifetimes
{
type EndpointError = #error;
type IncomingResponse =
<Response as #ruma_api_import::exports::ruma_common::Outgoing>::Incoming;
#[doc = #metadata_doc]
const METADATA: #ruma_api_import::Metadata = __METADATA;
#[allow(unused_mut, unused_variables)]
fn try_into_http_request(
self,
base_url: &::std::primitive::str,
access_token: ::std::option::Option<&str>,
) -> ::std::result::Result<
#ruma_api_import::exports::http::Request<Vec<u8>>,
#ruma_api_import::error::IntoHttpError,
> {
let metadata = <Self as #ruma_api_import::OutgoingRequest>::METADATA;
let mut req_builder = #ruma_api_import::exports::http::Request::builder()
.method(#ruma_api_import::exports::http::Method::#method)
.uri(::std::format!(
"{}{}{}",
base_url.strip_suffix("/").unwrap_or(base_url),
#request_path_string,
#request_query_string,
));
#header_kvs
let http_request = req_builder.body(#request_body)?;
Ok(http_request)
}
}
impl #ruma_api_import::IncomingRequest for #incoming_request_type {
type EndpointError = #error;
type OutgoingResponse = Response;
#[doc = #metadata_doc]
const METADATA: #ruma_api_import::Metadata = __METADATA;
}
#non_auth_endpoint_impls
};
api.to_tokens(tokens);
}
}
/// Custom keyword macros for syn.
mod kw {
use syn::custom_keyword;
custom_keyword!(metadata);
custom_keyword!(request);
custom_keyword!(response);
custom_keyword!(error);
}
/// The entire `ruma_api!` macro structure directly as it appears in the source code..
pub struct RawApi {
/// The `metadata` section of the macro.
pub metadata: RawMetadata,
/// The `request` section of the macro.
pub request: RawRequest,
/// The `response` section of the macro.
pub response: RawResponse,
/// The `error` section of the macro.
pub error: Option<RawErrorType>,
}
impl Parse for RawApi {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
Ok(Self {
metadata: input.parse()?,
request: input.parse()?,
response: input.parse()?,
error: input.parse().ok(),
})
}
}
pub struct RawMetadata {
pub metadata_kw: kw::metadata,
pub field_values: Vec<FieldValue>,
}
impl Parse for RawMetadata {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let metadata_kw = input.parse::<kw::metadata>()?;
input.parse::<Token![:]>()?;
let field_values;
braced!(field_values in input);
Ok(Self {
metadata_kw,
field_values: field_values
.parse_terminated::<FieldValue, Token![,]>(FieldValue::parse)?
.into_iter()
.collect(),
})
}
}
pub struct RawRequest {
pub attributes: Vec<Attribute>,
pub request_kw: kw::request,
pub fields: Vec<Field>,
}
impl Parse for RawRequest {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let attributes = input.call(Attribute::parse_outer)?;
let request_kw = input.parse::<kw::request>()?;
input.parse::<Token![:]>()?;
let fields;
braced!(fields in input);
Ok(Self {
attributes,
request_kw,
fields: fields
.parse_terminated::<Field, Token![,]>(Field::parse_named)?
.into_iter()
.collect(),
})
}
}
pub struct RawResponse {
pub attributes: Vec<Attribute>,
pub response_kw: kw::response,
pub fields: Vec<Field>,
}
impl Parse for RawResponse {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let attributes = input.call(Attribute::parse_outer)?;
let response_kw = input.parse::<kw::response>()?;
input.parse::<Token![:]>()?;
let fields;
braced!(fields in input);
Ok(Self {
attributes,
response_kw,
fields: fields
.parse_terminated::<Field, Token![,]>(Field::parse_named)?
.into_iter()
.map(|f| {
if util::has_lifetime(&f.ty) {
Err(syn::Error::new(
f.ident.span(),
"Lifetimes on Response fields cannot be supported until GAT are stable",
))
} else {
Ok(f)
}
})
.collect::<Result<Vec<_>, _>>()?,
})
}
}
pub struct RawErrorType {
pub error_kw: kw::error,
pub ty: Type,
}
impl Parse for RawErrorType {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let error_kw = input.parse::<kw::error>()?;
input.parse::<Token![:]>()?;
let ty = input.parse()?;
Ok(Self { error_kw, ty })
}
}