subxt-core crate (#1466)

* start migrating, broken

* first iteration of updating

* fmt and clippy

* add Composite<u32> decoding via scale value patch

* bump scale type gen versions

* fix decoding with new scale decode

* compiling with changed deps

* core utils, condig, client, metadata

* core crate compiling

* signer crate no once lock

* add core to no-std-tests, change imports

* broken commit, start pulling everything together in subxt

* port more things to subxt

* events in core crate, extrinsics sadly much more difficult

* almost all examples pass again

* dynamic values fix in examples

* fix no std issue and fmt

* remove unused dependencies

* fix lightclient impl

* runtime version refactor

* formatting and addressing nits

* more comments addressed

* update wasm example and no-std-signer tests

* other nits and error impl on signer errors

* fix feature flag

* fix runtime version refactor

* fix doc links

* fix integration tests

* fix feature flag gated client state

* fix native feature in CI

* fix lightclient utils

* make imports more lean in subxt-core

* integrate changes from subxt-core imports into subxt

* other changes in subxt simplify imports more

* fix  and docs

* doc false for cli

* fix clippy

* remove events block hash in tests

* codegen no-std support in generated code

* export alloc crate for no-std codegen

* fix doc test

* implement James comments

* remove std traits, use core traits instead

* address nits

* remove unusued dep in no-std tests

* fix Box import in no_std

* sp-crypto-hashing instead of sp-core-hashing

* bump scale-typegen, add no std codegen tests

* fix some things

* replace unmaintained derivative with derive_where to remove non-canonical warnings

* fmt

* remove unused dep

* fix deps

* update artifacts to fix type ID mismatches

* bump to latest scale-typegen

---------

Co-authored-by: James Wilson <james@jsdw.me>

subxt/src/constants/constants_client.rs

@@ -3,17 +3,11 @@
 // see LICENSE for license details.
 
 use super::ConstantAddress;
-use crate::{
-    client::OfflineClientT,
-    error::{Error, MetadataError},
-    metadata::DecodeWithMetadata,
-    Config,
-};
-use derivative::Derivative;
+use crate::{client::OfflineClientT, error::Error, Config};
+use derive_where::derive_where;
 
 /// A client for accessing constants.
-#[derive(Derivative)]
-#[derivative(Clone(bound = "Client: Clone"))]
+#[derive_where(Clone; Client)]
 pub struct ConstantsClient<T, Client> {
     client: Client,
     _marker: std::marker::PhantomData<T>,
@@ -35,20 +29,8 @@ impl<T: Config, Client: OfflineClientT<T>> ConstantsClient<T, Client> {
     /// Return an error if the address was not valid or something went wrong trying to validate it (ie
     /// the pallet or constant in question do not exist at all).
     pub fn validate<Address: ConstantAddress>(&self, address: &Address) -> Result<(), Error> {
-        if let Some(actual_hash) = address.validation_hash() {
-            let expected_hash = self
-                .client
-                .metadata()
-                .pallet_by_name_err(address.pallet_name())?
-                .constant_hash(address.constant_name())
-                .ok_or_else(|| {
-                    MetadataError::ConstantNameNotFound(address.constant_name().to_owned())
-                })?;
-            if actual_hash != expected_hash {
-                return Err(MetadataError::IncompatibleCodegen.into());
-            }
-        }
-        Ok(())
+        let metadata = self.client.metadata();
+        subxt_core::constants::validate_constant(&metadata, address).map_err(Error::from)
     }
 
     /// Access the constant at the address given, returning the type defined by this address.
@@ -59,22 +41,6 @@ impl<T: Config, Client: OfflineClientT<T>> ConstantsClient<T, Client> {
         address: &Address,
     ) -> Result<Address::Target, Error> {
         let metadata = self.client.metadata();
-
-        // 1. Validate constant shape if hash given:
-        self.validate(address)?;
-
-        // 2. Attempt to decode the constant into the type given:
-        let constant = metadata
-            .pallet_by_name_err(address.pallet_name())?
-            .constant_by_name(address.constant_name())
-            .ok_or_else(|| {
-                MetadataError::ConstantNameNotFound(address.constant_name().to_owned())
-            })?;
-        let value = <Address::Target as DecodeWithMetadata>::decode_with_metadata(
-            &mut constant.value(),
-            constant.ty(),
-            &metadata,
-        )?;
-        Ok(value)
+        subxt_core::constants::get_constant(&metadata, address).map_err(Error::from)
     }
 }