Remove requirement on Hash = H256, make Proposer return StorageChanges and Proof (#3860)

* Extend `Proposer` to optionally generate a proof of the proposal

* Something

* Refactor sr-api to not depend on client anymore

* Fix benches

* Apply suggestions from code review

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Apply suggestions from code review

* Introduce new `into_storage_changes` function

* Switch to runtime api for `execute_block` and don't require `H256`
anywhere in the code

* Put the `StorageChanges` into the `Proposal`

* Move the runtime api error to its own trait

* Adds `StorageTransactionCache` to the runtime api

This requires that we add `type NodeBlock = ` to the
`impl_runtime_apis!` macro to work around some bugs in rustc :(

* Remove `type NodeBlock` and switch to a "better" hack

* Start using the transaction cache from the runtime api

* Make it compile

* Move `InMemory` to its own file

* Make all tests work again

* Return block, storage_changes and proof from Blockbuilder::bake()

* Make sure that we use/set `storage_changes` when possible

* Add test

* Fix deadlock

* Remove accidentally added folders

* Introduce `RecordProof` as argument type to be more explicit

* Update client/src/client.rs

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Update primitives/state-machine/src/ext.rs

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Integrates review feedback

* Remove `unsafe` usage

* Update client/block-builder/src/lib.rs

Co-Authored-By: Benjamin Kampmann <ben@gnunicorn.org>

* Update client/src/call_executor.rs

* Bump versions

Co-authored-by: Tomasz Drwięga <tomusdrw@users.noreply.github.com>
Co-authored-by: Benjamin Kampmann <ben.kampmann@googlemail.com>

substrate/primitives/api/proc-macro/src/utils.rs

@@ -18,6 +18,7 @@ use proc_macro2::{TokenStream, Span};
 
 use syn::{
 	Result, Ident, Signature, parse_quote, Type, Pat, spanned::Spanned, FnArg, Error, token::And,
+	ImplItem, ReturnType,
 };
 
 use quote::quote;
@@ -26,11 +27,6 @@ use std::env;
 
 use proc_macro_crate::crate_name;
 
-/// Unwrap the given result, if it is an error, `compile_error!` will be generated.
-pub fn unwrap_or_error(res: Result<TokenStream>) -> TokenStream {
-	res.unwrap_or_else(|e| e.to_compile_error())
-}
-
 fn generate_hidden_includes_mod_name(unique_id: &'static str) -> Ident {
 	Ident::new(&format!("sp_api_hidden_includes_{}", unique_id), Span::call_site())
 }
@@ -81,10 +77,10 @@ pub fn generate_method_runtime_api_impl_name(trait_: &Ident, method: &Ident) ->
 }
 
 /// Get the type of a `syn::ReturnType`.
-pub fn return_type_extract_type(rt: &syn::ReturnType) -> Type {
+pub fn return_type_extract_type(rt: &ReturnType) -> Type {
 	match rt {
-		syn::ReturnType::Default => parse_quote!( () ),
-		syn::ReturnType::Type(_, ref ty) => *ty.clone(),
+		ReturnType::Default => parse_quote!( () ),
+		ReturnType::Type(_, ref ty) => *ty.clone(),
 	}
 }
 
@@ -176,3 +172,30 @@ pub fn generate_call_api_at_fn_name(fn_name: &Ident) -> Ident {
 pub fn prefix_function_with_trait<F: ToString>(trait_: &Ident, function: &F) -> String {
 	format!("{}_{}", trait_.to_string(), function.to_string())
 }
+
+/// Extract all types that appear in signatures in the given `ImplItem`'s.
+///
+/// If a type is a reference, the inner type is extracted (without the reference).
+pub fn extract_all_signature_types(items: &[ImplItem]) -> Vec<Type> {
+	items.iter()
+		.filter_map(|i| match i {
+			ImplItem::Method(method) => Some(&method.sig),
+			_ => None,
+		})
+		.map(|sig| {
+			let ret_ty = match &sig.output {
+				ReturnType::Default => None,
+				ReturnType::Type(_, ty) => Some((**ty).clone()),
+			};
+
+			sig.inputs.iter().filter_map(|i| match i {
+				FnArg::Typed(arg) => Some(&arg.ty),
+				_ => None,
+			}).map(|ty| match &**ty {
+				Type::Reference(t) => (*t.elem).clone(),
+				_ => (**ty).clone(),
+			}).chain(ret_ty)
+		})
+		.flatten()
+		.collect()
+}