From 9c6368f87cd1463dd20575914823a35c1d92ffef Mon Sep 17 00:00:00 2001
From: Eric <e.lim0322@gmail.com>
Date: Tue, 19 Nov 2019 02:44:31 +1300
Subject: [PATCH] add hashed_key_for() getter method for StorageDoubleMap
 (#4120)

---
 .../paint/support/src/storage/generator/double_map.rs     | 8 ++++++++
 substrate/paint/support/src/storage/mod.rs                | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/substrate/paint/support/src/storage/generator/double_map.rs b/substrate/paint/support/src/storage/generator/double_map.rs
index cac8dbd034..072b530e4c 100644
--- a/substrate/paint/support/src/storage/generator/double_map.rs
+++ b/substrate/paint/support/src/storage/generator/double_map.rs
@@ -89,6 +89,14 @@ where
 {
 	type Query = G::Query;
 
+	fn hashed_key_for<KArg1, KArg2>(k1: KArg1, k2: KArg2) -> Vec<u8>
+	where
+		KArg1: EncodeLike<K1>,
+		KArg2: EncodeLike<K2>,
+	{
+		Self::storage_double_map_final_key(k1, k2)
+	}
+
 	fn exists<KArg1, KArg2>(k1: KArg1, k2: KArg2) -> bool
 	where
 		KArg1: EncodeLike<K1>,
diff --git a/substrate/paint/support/src/storage/mod.rs b/substrate/paint/support/src/storage/mod.rs
index af64d2a179..91e1776788 100644
--- a/substrate/paint/support/src/storage/mod.rs
+++ b/substrate/paint/support/src/storage/mod.rs
@@ -264,6 +264,11 @@ pub trait StorageDoubleMap<K1: FullEncode, K2: FullEncode, V: FullCodec> {
 	/// The type that get/take returns.
 	type Query;
 
+	fn hashed_key_for<KArg1, KArg2>(k1: KArg1, k2: KArg2) -> Vec<u8>
+	where
+		KArg1: EncodeLike<K1>,
+		KArg2: EncodeLike<K2>;
+
 	fn exists<KArg1, KArg2>(k1: KArg1, k2: KArg2) -> bool
 	where
 		KArg1: EncodeLike<K1>,