Double map and plain storage support, introduce macros (#93)

* Support custom clients.

* Simplify trait bounds.

* Plain and double map storage support.

* Simplify more trait bounds.

* Add proc macro.

* Add Call, Event and Store traits.

* Update proc-macros.

* Add with_system for proc-macro.

* proc-macro: test: support signature and extra fields.

* proc-macro: test: support sharing state accross steps.

* proc-macro: test: fetch state sequentially.

* Elide lifetimes.

* Add test for plain storage.

* Run rustfmt.

src/frame/system.rs

@@ -22,11 +22,8 @@ use codec::{
     Encode,
 };
 use frame_support::Parameter;
-use futures::future::{
-    self,
-    Future,
-};
 use serde::de::DeserializeOwned;
+use sp_core::storage::StorageKey;
 use sp_runtime::{
     traits::{
         AtLeast32Bit,
@@ -40,24 +37,21 @@ use sp_runtime::{
         MaybeSerialize,
         MaybeSerializeDeserialize,
         Member,
-        SignedExtension,
         SimpleBitOps,
     },
     RuntimeDebug,
 };
-use std::{
-    fmt::Debug,
-    pin::Pin,
-};
+use std::fmt::Debug;
 
 use crate::{
-    error::Error,
-    extrinsic::SignedExtra,
     frame::{
-        balances::Balances,
         Call,
+        Store,
+    },
+    metadata::{
+        Metadata,
+        MetadataError,
     },
-    Client,
 };
 
 /// The subset of the `frame::Trait` that a client must implement.
@@ -116,7 +110,7 @@ pub trait System: 'static + Eq + Clone + Debug {
         + Default;
 
     /// The address type. This instead of `<frame_system::Trait::Lookup as StaticLookup>::Source`.
-    type Address: Codec + Clone + PartialEq + Debug;
+    type Address: Codec + Clone + PartialEq + Debug + Send + Sync;
 
     /// The block header.
     type Header: Parameter
@@ -147,59 +141,33 @@ pub struct AccountInfo<T: System> {
     pub data: T::AccountData,
 }
 
-/// The System extension trait for the Client.
-pub trait SystemStore {
-    /// System type.
-    type System: System;
+const MODULE: &str = "System";
 
-    /// Returns the nonce and account data for an account_id.
-    fn account(
-        &self,
-        account_id: <Self::System as System>::AccountId,
-    ) -> Pin<Box<dyn Future<Output = Result<AccountInfo<Self::System>, Error>> + Send>>;
-}
+/// Account field of the `System` module.
+#[derive(Encode)]
+pub struct AccountStore<'a, T: System>(pub &'a T::AccountId);
 
-impl<T: System + Balances + Sync + Send + 'static, S: 'static, E> SystemStore
-    for Client<T, S, E>
-where
-    E: SignedExtra<T> + SignedExtension + 'static,
-{
-    type System = T;
+impl<'a, T: System> Store<T> for AccountStore<'a, T> {
+    const MODULE: &'static str = MODULE;
+    const FIELD: &'static str = "Account";
+    type Returns = AccountInfo<T>;
 
-    fn account(
-        &self,
-        account_id: <Self::System as System>::AccountId,
-    ) -> Pin<Box<dyn Future<Output = Result<AccountInfo<Self::System>, Error>> + Send>>
-    {
-        let account_map = || {
-            Ok(self
-                .metadata
-                .module("System")?
-                .storage("Account")?
-                .get_map()?)
-        };
-        let map = match account_map() {
-            Ok(map) => map,
-            Err(err) => return Box::pin(future::err(err)),
-        };
-        let client = self.clone();
-        Box::pin(async move {
-            client
-                .fetch_or(map.key(account_id), None, map.default())
-                .await
-        })
+    fn key(&self, metadata: &Metadata) -> Result<StorageKey, MetadataError> {
+        Ok(metadata
+            .module(Self::MODULE)?
+            .storage(Self::FIELD)?
+            .map()?
+            .key(self.0))
     }
 }
 
-const MODULE: &str = "System";
-const SET_CODE: &str = "set_code";
-
 /// Arguments for updating the runtime code
-pub type SetCode = Vec<u8>;
+#[derive(Encode)]
+pub struct SetCodeCall<'a>(pub &'a Vec<u8>);
 
-/// Sets the new code.
-pub fn set_code(code: Vec<u8>) -> Call<SetCode> {
-    Call::new(MODULE, SET_CODE, code)
+impl<'a, T: System> Call<T> for SetCodeCall<'a> {
+    const MODULE: &'static str = MODULE;
+    const FUNCTION: &'static str = "set_code";
 }
 
 use frame_support::weights::DispatchInfo;