1 files changed, 71 insertions, 0 deletions
diff --git a/alacritty_config_derive/src/config_deserialize/de_enum.rs b/alacritty_config_derive/src/config_deserialize/de_enum.rs
new file mode 100644
index 00000000..73634e73
--- /dev/null
+++ b/alacritty_config_derive/src/config_deserialize/de_enum.rs
@@ -0,0 +1,71 @@
+use proc_macro::TokenStream;
+use proc_macro2::TokenStream as TokenStream2;
+use quote::{format_ident, quote};
+use syn::{DataEnum, Generics, Ident};
+
+use crate::serde_replace;
+
+pub fn derive_deserialize(ident: Ident, generics: Generics, data_enum: DataEnum) -> TokenStream {
+    let visitor = format_ident!("{}Visitor", ident);
+
+    // Create match arm streams and get a list with all available values.
+    let mut match_arms_stream = TokenStream2::new();
+    let mut available_values = String::from("one of ");
+    for variant in data_enum.variants.iter().filter(|variant| {
+        // Skip deserialization for `#[config(skip)]` fields.
+        variant.attrs.iter().all(|attr| {
+            !crate::path_ends_with(&attr.path, "config") || attr.tokens.to_string() != "(skip)"
+        })
+    }) {
+        let variant_ident = &variant.ident;
+        let variant_str = variant_ident.to_string();
+        available_values = format!("{}`{}`, ", available_values, variant_str);
+
+        let literal = variant_str.to_lowercase();
+
+        match_arms_stream.extend(quote! {
+            #literal => Ok(#ident :: #variant_ident),
+        });
+    }
+
+    // Remove trailing `, ` from the last enum variant.
+    available_values.truncate(available_values.len().saturating_sub(2));
+
+    // Generate deserialization impl.
+    let mut tokens = quote! {
+        struct #visitor;
+        impl<'de> serde::de::Visitor<'de> for #visitor {
+            type Value = #ident;
+
+            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                formatter.write_str(#available_values)
+            }
+
+            fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
+            where
+                E: serde::de::Error,
+            {
+                match s.to_lowercase().as_str() {
+                    #match_arms_stream
+                    _ => Err(E::custom(
+                            &format!("unknown variant `{}`, expected {}", s, #available_values)
+                    )),
+                }
+            }
+        }
+
+        impl<'de> serde::Deserialize<'de> for #ident {
+            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+            where
+                D: serde::Deserializer<'de>,
+            {
+                deserializer.deserialize_str(#visitor)
+            }
+        }
+    };
+
+    // Automatically implement [`alacritty_config::SerdeReplace`].
+    tokens.extend(serde_replace::derive_direct(ident, generics));
+
+    tokens.into()
+}