Add experimental async support

rust-toolchain

@@ -0,0 +1 @@
+nightly

src/lib.rs

@@ -1,3 +1,4 @@
+#![feature(async_fn_in_trait, impl_trait_projections)]
 // #![feature(result_option_inspect)]
 #![cfg_attr(not(feature = "std"), no_std)]
 //! `libwallet` is the one-stop tool to build easy, slightly opinionated crypto wallets
@@ -14,7 +15,7 @@ mod key_pair;
 mod substrate_ext;
 
 use arrayvec::ArrayVec;
-use core::{convert::TryInto, fmt, future::Future};
+use core::{convert::TryInto, fmt};
 use key_pair::any::AnySignature;
 
 #[cfg(feature = "mnemonic")]
@@ -32,13 +33,12 @@ type Message = ArrayVec<u8, { MSG_MAX_SIZE }>;
 /// Abstration for storage of private keys that are protected by some credentials.
 pub trait Vault {
     type Credentials;
-    type AuthDone: Future<Output = core::result::Result<(), Self::Error>>;
     type Error;
 
     /// Use a set of credentials to make the guarded keys available to the user.
     /// It returns a `Future` to allow for vaults that might take an arbitrary amount
     /// of time getting the secret ready like waiting for some user phisical interaction.
-    fn unlock(&mut self, cred: impl Into<Self::Credentials>) -> Self::AuthDone;
+    async fn unlock(&mut self, cred: impl Into<Self::Credentials>) -> Result<(), Self::Error>;
 
     /// Get the root account container of the supported private key pairs
     /// if the vault hasn't been unlocked it should return `None`

src/vault/os.rs

@@ -91,13 +91,11 @@ impl std::error::Error for Error {}
 
 impl Vault for OSKeyring {
     type Credentials = Pin;
-    type AuthDone = Ready<Result<(), Self::Error>>;
     type Error = Error;
 
-    fn unlock(&mut self, pin: impl Into<Self::Credentials>) -> Self::AuthDone {
+    async fn unlock(&mut self, pin: impl Into<Self::Credentials>) -> Result<(), Self::Error> {
         let pin = pin.into();
-        let res = self
-            .get_key(&pin)
+        self.get_key(&pin)
             .or_else(|err| {
                 self.auto_generate
                     .ok_or(err)
@@ -106,8 +104,7 @@ impl Vault for OSKeyring {
             .and_then(move |r| {
                 self.root = Some(r);
                 Ok(())
-            });
-        core::future::ready(res)
+            })
     }
 
     fn get_root(&self) -> Option<&RootAccount> {

src/vault/pass.rs

@@ -118,12 +118,10 @@ pub struct PassCreds {
 impl Vault for Pass {
     type Credentials = PassCreds;
     type Error = Error;
-    type AuthDone = Ready<Result<(), Self::Error>>;
 
-    fn unlock(&mut self, creds: impl Into<Self::Credentials>) -> Self::AuthDone {
+    async fn unlock(&mut self, creds: impl Into<Self::Credentials>) -> Result<(), Self::Error> {
         let creds = creds.into();
-        let res = self
-            .get_key(&creds)
+        self.get_key(&creds)
             .or_else(|err| {
                 self.auto_generate
                     .ok_or(err)
@@ -132,8 +130,7 @@ impl Vault for Pass {
             .and_then(move |r| {
                 self.root = Some(r);
                 Ok(())
-            });
-        core::future::ready(res)
+            })
     }
 
     fn get_root(&self) -> Option<&RootAccount> {

src/vault/simple.rs

@@ -1,5 +1,3 @@
-use core::future::{ready, Ready};
-
 use crate::{RootAccount, Vault};
 
 /// A vault that holds secrets in memory
@@ -80,11 +78,10 @@ impl std::error::Error for Error {}
 impl Vault for Simple {
     type Credentials = ();
     type Error = Error;
-    type AuthDone = Ready<Result<(), Self::Error>>;
 
-    fn unlock(&mut self, _cred: impl Into<Self::Credentials>) -> Self::AuthDone {
+    async fn unlock(&mut self, _cred: impl Into<Self::Credentials>) -> Result<(), Self::Error> {
         self.unlocked = self.locked.take();
-        ready(Ok(()))
+        Ok(())
     }
 
     fn get_root(&self) -> Option<&RootAccount> {