Refactoring of schemars_derive

schemars_derive/src/attr/mod.rs

@@ -0,0 +1,71 @@
+mod doc;
+mod schemars_to_serde;
+
+pub use doc::get_title_and_desc_from_doc;
+pub use schemars_to_serde::process_serde_attrs;
+
+use proc_macro2::{Group, Span, TokenStream, TokenTree};
+use syn::parse::{self, Parse};
+
+pub fn get_with_from_attrs(field: &syn::Field) -> Option<syn::Result<syn::ExprPath>> {
+    field
+        .attrs
+        .iter()
+        .filter(|at| match at.path.get_ident() {
+            // FIXME this is relying on order of attributes (schemars before serde) from preprocess.rs
+            Some(i) => i == "schemars" || i == "serde",
+            None => false,
+        })
+        .filter_map(get_with_from_attr)
+        .next()
+        .map(|lit| parse_lit_str(&lit))
+}
+
+fn get_with_from_attr(attr: &syn::Attribute) -> Option<syn::LitStr> {
+    use syn::*;
+    let nested_metas = match attr.parse_meta() {
+        Ok(Meta::List(meta)) => meta.nested,
+        _ => return None,
+    };
+    for nm in nested_metas {
+        if let NestedMeta::Meta(Meta::NameValue(MetaNameValue {
+            path,
+            lit: Lit::Str(with),
+            ..
+        })) = nm
+        {
+            if path.is_ident("with") {
+                return Some(with);
+            }
+        }
+    }
+    None
+}
+
+fn parse_lit_str<T>(s: &syn::LitStr) -> parse::Result<T>
+where
+    T: Parse,
+{
+    let tokens = spanned_tokens(s)?;
+    syn::parse2(tokens)
+}
+
+fn spanned_tokens(s: &syn::LitStr) -> parse::Result<TokenStream> {
+    let stream = syn::parse_str(&s.value())?;
+    Ok(respan_token_stream(stream, s.span()))
+}
+
+fn respan_token_stream(stream: TokenStream, span: Span) -> TokenStream {
+    stream
+        .into_iter()
+        .map(|token| respan_token_tree(token, span))
+        .collect()
+}
+
+fn respan_token_tree(mut token: TokenTree, span: Span) -> TokenTree {
+    if let TokenTree::Group(g) = &mut token {
+        *g = Group::new(g.delimiter(), respan_token_stream(g.stream(), span));
+    }
+    token.set_span(span);
+    token
+}