1 files changed, 114 insertions, 0 deletions
diff --git a/vendor/serde_repr/src/parse.rs b/vendor/serde_repr/src/parse.rs
new file mode 100644
index 000000000..2c0ad1e7d
--- /dev/null
+++ b/vendor/serde_repr/src/parse.rs
@@ -0,0 +1,114 @@
+use proc_macro2::Span;
+use syn::parse::{Error, Parse, ParseStream, Parser, Result};
+use syn::{parenthesized, Data, DeriveInput, Fields, Ident, Meta, NestedMeta};
+
+pub struct Input {
+    pub ident: Ident,
+    pub repr: Ident,
+    pub variants: Vec<Variant>,
+    pub default_variant: Option<Variant>,
+}
+
+#[derive(Clone)]
+pub struct Variant {
+    pub ident: Ident,
+    pub attrs: VariantAttrs,
+}
+
+#[derive(Clone)]
+pub struct VariantAttrs {
+    pub is_default: bool,
+}
+
+fn parse_meta(attrs: &mut VariantAttrs, meta: &Meta) {
+    if let Meta::List(value) = meta {
+        for meta in &value.nested {
+            if let NestedMeta::Meta(Meta::Path(path)) = meta {
+                if path.is_ident("other") {
+                    attrs.is_default = true;
+                }
+            }
+        }
+    }
+}
+
+fn parse_attrs(variant: &syn::Variant) -> Result<VariantAttrs> {
+    let mut attrs = VariantAttrs { is_default: false };
+    for attr in &variant.attrs {
+        if attr.path.is_ident("serde") {
+            parse_meta(&mut attrs, &attr.parse_meta()?);
+        }
+    }
+    Ok(attrs)
+}
+
+impl Parse for Input {
+    fn parse(input: ParseStream) -> Result<Self> {
+        let call_site = Span::call_site();
+        let derive_input = DeriveInput::parse(input)?;
+
+        let data = match derive_input.data {
+            Data::Enum(data) => data,
+            _ => {
+                return Err(Error::new(call_site, "input must be an enum"));
+            }
+        };
+
+        let variants = data
+            .variants
+            .into_iter()
+            .map(|variant| match variant.fields {
+                Fields::Unit => {
+                    let attrs = parse_attrs(&variant)?;
+                    Ok(Variant {
+                        ident: variant.ident,
+                        attrs,
+                    })
+                }
+                Fields::Named(_) | Fields::Unnamed(_) => {
+                    Err(Error::new(variant.ident.span(), "must be a unit variant"))
+                }
+            })
+            .collect::<Result<Vec<Variant>>>()?;
+
+        if variants.is_empty() {
+            return Err(Error::new(call_site, "there must be at least one variant"));
+        }
+
+        let generics = derive_input.generics;
+        if !generics.params.is_empty() || generics.where_clause.is_some() {
+            return Err(Error::new(call_site, "generic enum is not supported"));
+        }
+
+        let mut repr = None;
+        for attr in derive_input.attrs {
+            if attr.path.is_ident("repr") {
+                fn repr_arg(input: ParseStream) -> Result<Ident> {
+                    let content;
+                    parenthesized!(content in input);
+                    content.parse()
+                }
+                let ty = repr_arg.parse2(attr.tokens)?;
+                repr = Some(ty);
+                break;
+            }
+        }
+        let repr = repr.ok_or_else(|| Error::new(call_site, "missing #[repr(...)] attribute"))?;
+
+        let mut default_variants = variants.iter().filter(|x| x.attrs.is_default);
+        let default_variant = default_variants.next().cloned();
+        if default_variants.next().is_some() {
+            return Err(Error::new(
+                call_site,
+                "only one variant can be #[serde(other)]",
+            ));
+        }
+
+        Ok(Input {
+            ident: derive_input.ident,
+            repr,
+            variants,
+            default_variant,
+        })
+    }
+}