From bac71feb0141514ec28bae28e6a6fa9f9884f516 Mon Sep 17 00:00:00 2001
From: Amar Singh <asinghchrony@protonmail.com>
Date: Mon, 11 Apr 2022 04:45:59 -0400
Subject: [PATCH] Make functionality to read relay state proof entries public
(#1135)
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* add read entry and read optional entry to RelayChainStateProof pub methods
* rm toolchain
* docs
* Update pallets/parachain-system/src/relay_state_snapshot.rs
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
---
.../src/relay_state_snapshot.rs | 28 +++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/cumulus/pallets/parachain-system/src/relay_state_snapshot.rs b/cumulus/pallets/parachain-system/src/relay_state_snapshot.rs
index ba3149119fd..9f69dd94762 100644
--- a/cumulus/pallets/parachain-system/src/relay_state_snapshot.rs
+++ b/cumulus/pallets/parachain-system/src/relay_state_snapshot.rs
@@ -63,6 +63,10 @@ pub struct MessagingStateSnapshot {
pub enum Error {
/// The provided proof was created against unexpected storage root.
RootMismatch,
+ /// The entry cannot be read.
+ ReadEntry(ReadEntryErr),
+ /// The optional entry cannot be read.
+ ReadOptionalEntry(ReadEntryErr),
/// The slot cannot be extracted.
Slot(ReadEntryErr),
/// The upgrade go-ahead signal cannot be read.
@@ -273,4 +277,28 @@ impl RelayChainStateProof {
)
.map_err(Error::UpgradeRestriction)
}
+
+ /// Read an entry given by the key and try to decode it. If the value specified by the key according
+ /// to the proof is empty, the `fallback` value will be returned.
+ ///
+ /// Returns `Err` in case the backend can't return the value under the specific key (likely due to
+ /// a malformed proof), in case the decoding fails, or in case where the value is empty in the relay
+ /// chain state and no fallback was provided.
+ pub fn read_entry<T>(&self, key: &[u8], fallback: Option<T>) -> Result<T, Error>
+ where
+ T: Decode,
+ {
+ read_entry(&self.trie_backend, key, fallback).map_err(Error::ReadEntry)
+ }
+
+ /// Read an optional entry given by the key and try to decode it.
+ ///
+ /// Returns `Err` in case the backend can't return the value under the specific key (likely due to
+ /// a malformed proof) or if the value couldn't be decoded.
+ pub fn read_optional_entry<T>(&self, key: &[u8]) -> Result<Option<T>, Error>
+ where
+ T: Decode,
+ {
+ read_optional_entry(&self.trie_backend, key).map_err(Error::ReadOptionalEntry)
+ }
}
--
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