schemars/schemars_derive/src/metadata.rs
2021-03-27 10:34:39 +00:00

116 lines
3 KiB
Rust

use crate::attr;
use attr::Attrs;
use proc_macro2::{Ident, Span, TokenStream};
use quote::{ToTokens, TokenStreamExt};
#[derive(Debug, Clone)]
pub struct SchemaMetadata<'a> {
pub title: Option<&'a str>,
pub description: Option<&'a str>,
pub deprecated: bool,
pub read_only: bool,
pub write_only: bool,
pub examples: &'a [syn::Path],
pub default: Option<TokenStream>,
}
impl ToTokens for SchemaMetadata<'_> {
fn to_tokens(&self, tokens: &mut TokenStream) {
let setters = self.make_setters();
if setters.is_empty() {
tokens.append(Ident::new("None", Span::call_site()))
} else {
tokens.extend(quote! {
Some({
schemars::schema::Metadata {
#(#setters)*
..Default::default()
}
})
})
}
}
}
impl<'a> SchemaMetadata<'a> {
pub fn from_attrs(attrs: &'a Attrs) -> Self {
SchemaMetadata {
title: attrs.title.as_ref().and_then(none_if_empty),
description: attrs.description.as_ref().and_then(none_if_empty),
deprecated: attrs.deprecated,
examples: &attrs.examples,
read_only: false,
write_only: false,
default: None,
}
}
pub fn apply_to_schema(&self, schema_expr: TokenStream) -> TokenStream {
quote! {
{
let schema = #schema_expr;
gen.apply_metadata(schema, #self)
}
}
}
fn make_setters(&self) -> Vec<TokenStream> {
let mut setters = Vec::<TokenStream>::new();
if let Some(title) = &self.title {
setters.push(quote! {
title: Some(#title.to_owned()),
});
}
if let Some(description) = &self.description {
setters.push(quote! {
description: Some(#description.to_owned()),
});
}
if self.deprecated {
setters.push(quote! {
deprecated: true,
});
}
if self.read_only {
setters.push(quote! {
read_only: true,
});
}
if self.write_only {
setters.push(quote! {
write_only: true,
});
}
if !self.examples.is_empty() {
let examples = self.examples.iter().map(|eg| {
quote! {
schemars::_serde_json::value::to_value(#eg())
}
});
setters.push(quote! {
examples: vec![#(#examples),*].into_iter().flatten().collect(),
});
}
if let Some(default) = &self.default {
setters.push(quote! {
default: #default.and_then(|d| schemars::_serde_json::value::to_value(d).ok()),
});
}
setters
}
}
#[allow(clippy::ptr_arg)]
fn none_if_empty(s: &String) -> Option<&str> {
if s.is_empty() {
None
} else {
Some(s)
}
}