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>

codegen/src/api/mod.rs

@@ -6,6 +6,7 @@
 
 mod calls;
 mod constants;
+mod custom_values;
 mod errors;
 mod events;
 mod runtime_apis;
@@ -14,6 +15,7 @@ mod storage;
 use subxt_metadata::Metadata;
 
 use super::DerivesRegistry;
+use crate::api::custom_values::generate_custom_values;
 use crate::error::CodegenError;
 use crate::{
     ir,
@@ -469,6 +471,8 @@ impl RuntimeGenerator {
         let event_path = type_gen.resolve_type_path(self.metadata.outer_enums().event_enum_ty());
         let error_path = type_gen.resolve_type_path(self.metadata.outer_enums().error_enum_ty());
 
+        let custom_values = generate_custom_values(&self.metadata, &type_gen, &crate_path);
+
         Ok(quote! {
             #( #item_mod_attrs )*
             #[allow(dead_code, unused_imports, non_camel_case_types)]
@@ -521,6 +525,12 @@ impl RuntimeGenerator {
 
                 #apis_mod
 
+                pub fn custom() -> CustomValuesApi {
+                    CustomValuesApi
+                }
+
+                #custom_values
+
                 pub struct ConstantsApi;
                 impl ConstantsApi {
                     #(