From f6f8720c7424ddd485bb9c0a2ad42df90287127c Mon Sep 17 00:00:00 2001
From: Alexander Simmerl <a.simmerl@gmail.com>
Date: Tue, 15 Jun 2021 13:27:18 +0200
Subject: [PATCH] tendermint: Add TryFrom for node::Id from PublicKey (#903)

Convenience to obtain a `node::Id` from a PublicKey, which is especially
useful in the context p2p and protocols built on top of it as the main
reference a peer is catalogued by is the `node::Id`.

Signed-off-by: Alexander Simmerl <a.simmerl@gmail.com>
---
 tendermint/src/error.rs   |  4 ++++
 tendermint/src/node/id.rs | 28 +++++++++++++++++++++-------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/tendermint/src/error.rs b/tendermint/src/error.rs
index f5c678a48..0df48310d 100644
--- a/tendermint/src/error.rs
+++ b/tendermint/src/error.rs
@@ -20,6 +20,10 @@ pub enum Kind {
     #[error("invalid key")]
     InvalidKey,
 
+    /// Unsupported public key type.
+    #[error("unsupported key type")]
+    UnsupportedKeyType,
+
     /// Input/output error
     #[error("I/O error")]
     Io,
diff --git a/tendermint/src/node/id.rs b/tendermint/src/node/id.rs
index 675181aa7..7cedc02e9 100644
--- a/tendermint/src/node/id.rs
+++ b/tendermint/src/node/id.rs
@@ -1,19 +1,21 @@
 //! Tendermint node IDs
 
-use crate::{
-    error::{Error, Kind},
-    public_key::Ed25519,
-};
-
-use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
-use sha2::{Digest, Sha256};
 use std::{
+    convert::TryFrom,
     fmt::{self, Debug, Display},
     str::FromStr,
 };
+
+use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
+use sha2::{Digest, Sha256};
 use subtle::{self, ConstantTimeEq};
 use subtle_encoding::hex;
 
+use crate::{
+    error::{Error, Kind},
+    public_key::{Ed25519, PublicKey},
+};
+
 /// Length of a Node ID in bytes
 pub const LENGTH: usize = 20;
 
@@ -96,6 +98,18 @@ impl PartialEq for Id {
     }
 }
 
+impl TryFrom<PublicKey> for Id {
+    type Error = Error;
+
+    fn try_from(pk: PublicKey) -> Result<Self, Self::Error> {
+        match pk {
+            PublicKey::Ed25519(ed25519) => Ok(Id::from(ed25519)),
+            #[cfg(feature = "secp256k1")]
+            _ => Err(Kind::UnsupportedKeyType.into()),
+        }
+    }
+}
+
 impl<'de> Deserialize<'de> for Id {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where