Codegen for custom values in metadata (#1117)

* work in progress * add custom types access * nit * custom values client * adjust light client * adjust doc comments * adjust book for custom values in code gen * format and check docs * work in progress * add custom types access * nit * custom values client * adjust light client * codegen and validation * adjust docs * use ignore in docs in book * change iter implementation * use validation hash and other codegen changes * add ui test for custom values codegen * allow 'latest' metadata to be returned from the fallback code (#1127) * nits * fix validation check * fix comments * nits --------- Co-authored-by: James Wilson <james@jsdw.me>
2026-04-22 05:37:58 +00:00 · 2023-08-24 09:50:44 +02:00
parent a8dbd9d6d5
commit b413e5e84e
12 changed files with 354 additions and 43 deletions
@@ -0,0 +1,61 @@
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
+// This file is dual-licensed as Apache-2.0 or GPL-3.0.
+// see LICENSE for license details.
+
+use std::collections::HashSet;
+
+use crate::{types::TypeGenerator, CratePath};
+use heck::ToSnakeCase as _;
+use subxt_metadata::{CustomValueMetadata, Metadata};
+
+use proc_macro2::TokenStream as TokenStream2;
+use quote::{format_ident, quote};
+
+/// Generate the custom values mod, if there are any custom values in the metadata. Else returns None.
+pub fn generate_custom_values<'a>(
+    metadata: &'a Metadata,
+    type_gen: &'a TypeGenerator,
+    crate_path: &'a CratePath,
+) -> TokenStream2 {
+    let mut fn_names_taken = HashSet::new();
+    let custom = metadata.custom();
+    let custom_values_fns = custom.iter().filter_map(|custom_value| {
+        generate_custom_value_fn(custom_value, type_gen, crate_path, &mut fn_names_taken)
+    });
+
+    quote! {
+        pub struct CustomValuesApi;
+
+        impl CustomValuesApi {
+            #(#custom_values_fns)*
+        }
+    }
+}
+
+/// Generates runtime functions for the given API metadata.
+/// Returns None, if the name would not make for a valid identifier.
+fn generate_custom_value_fn(
+    custom_value: CustomValueMetadata,
+    type_gen: &TypeGenerator,
+    crate_path: &CratePath,
+    fn_names_taken: &mut HashSet<String>,
+) -> Option<TokenStream2> {
+    // names are transformed to snake case to make for good function identifiers.
+    let name = custom_value.name();
+    let fn_name = name.to_snake_case();
+    // Skip elements where the fn name is already occupied. E.g. if you have custom values with names "Foo" and "foo" in the metadata.
+    if fn_names_taken.contains(&fn_name) {
+        return None;
+    }
+    let fn_name_ident = format_ident!("{fn_name}");
+    fn_names_taken.insert(fn_name);
+
+    let custom_value_hash = custom_value.hash();
+    let return_ty = type_gen.resolve_type_path(custom_value.type_id());
+
+    Some(quote!(
+        pub fn #fn_name_ident() -> #crate_path::custom_values::StaticAddress<#return_ty> {
+            #crate_path::custom_values::StaticAddress::new_static(#name, [#(#custom_value_hash,)*])
+        }
+    ))
+}