From 2e5da3cb72a5fb7dd07c96ecbf4bc209701f67be Mon Sep 17 00:00:00 2001
From: Chris Sosnin <48099298+slumber@users.noreply.github.com>
Date: Tue, 21 Mar 2023 16:13:20 +0300
Subject: [PATCH] introduce new well known key (#6915)
---
polkadot/primitives/src/v4/mod.rs | 17 +++++++++++++++++
polkadot/runtime/parachains/src/paras/tests.rs | 15 +++++++++++++++
2 files changed, 32 insertions(+)
diff --git a/polkadot/primitives/src/v4/mod.rs b/polkadot/primitives/src/v4/mod.rs
index 82d7954b809..efd6db836c2 100644
--- a/polkadot/primitives/src/v4/mod.rs
+++ b/polkadot/primitives/src/v4/mod.rs
@@ -187,6 +187,23 @@ pub mod well_known_keys {
pub const ACTIVE_CONFIG: &[u8] =
&hex!["06de3d8a54d27e44a9d5ce189618f22db4b49d95320d9021994c850f25b8e385"];
+ /// Hash of the committed head data for a given registered para.
+ ///
+ /// The storage entry stores wrapped `HeadData(Vec<u8>)`.
+ pub fn para_head(para_id: Id) -> Vec<u8> {
+ let prefix = hex!["cd710b30bd2eab0352ddcc26417aa1941b3c252fcb29d88eff4f3de5de4476c3"];
+
+ para_id.using_encoded(|para_id: &[u8]| {
+ prefix
+ .as_ref()
+ .iter()
+ .chain(twox_64(para_id).iter())
+ .chain(para_id.iter())
+ .cloned()
+ .collect()
+ })
+ }
+
/// The upward message dispatch queue for the given para id.
///
/// The storage entry stores a tuple of two values:
diff --git a/polkadot/runtime/parachains/src/paras/tests.rs b/polkadot/runtime/parachains/src/paras/tests.rs
index 567829b9aef..dff5222baa3 100644
--- a/polkadot/runtime/parachains/src/paras/tests.rs
+++ b/polkadot/runtime/parachains/src/paras/tests.rs
@@ -1700,6 +1700,21 @@ fn verify_upgrade_restriction_signal_is_externally_accessible() {
});
}
+#[test]
+fn verify_para_head_is_externally_accessible() {
+ use primitives::well_known_keys;
+
+ let a = ParaId::from(2020);
+ let expected_head_data = HeadData(vec![0, 1, 2, 3]);
+
+ new_test_ext(Default::default()).execute_with(|| {
+ Heads::<Test>::insert(&a, expected_head_data.clone());
+ let encoded = sp_io::storage::get(&well_known_keys::para_head(a)).unwrap();
+ let head_data = HeadData::decode(&mut encoded.as_ref());
+ assert_eq!(head_data, Ok(expected_head_data));
+ });
+}
+
#[test]
fn parakind_encodes_decodes_to_bool_scale() {
let chain_kind = ParaKind::Parachain.encode();
--
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