rpc-v2: Implement archive_unstable_storageDiff

substrate/client/rpc-spec-v2/Cargo.toml

@@ -42,6 +42,7 @@ log = { workspace = true, default-features = true }
 futures-util = { workspace = true }
 rand = { workspace = true, default-features = true }
 schnellru = { workspace = true }
+itertools = { workspace = true }
 
 [dev-dependencies]
 jsonrpsee = { workspace = true, features = ["server", "ws-client"] }

substrate/client/rpc-spec-v2/src/archive/api.rs

@@ -19,7 +19,10 @@
 //! API trait of the archive methods.
 
 use crate::{
-	common::events::{ArchiveStorageResult, PaginatedStorageQuery},
+	common::events::{
+		ArchiveStorageDiffItem, ArchiveStorageDiffMethodResult, ArchiveStorageResult,
+		PaginatedStorageQuery,
+	},
 	MethodResult,
 };
 use jsonrpsee::{core::RpcResult, proc_macros::rpc};
@@ -104,4 +107,17 @@ pub trait ArchiveApi<Hash> {
 		items: Vec<PaginatedStorageQuery<String>>,
 		child_trie: Option<String>,
 	) -> RpcResult<ArchiveStorageResult>;
+
+	/// Returns the storage difference between two blocks.
+	///
+	/// # Unstable
+	///
+	/// This method is unstable and subject to change in the future.
+	#[method(name = "archive_unstable_storageDiff", blocking)]
+	fn archive_unstable_storage_diff(
+		&self,
+		hash: Hash,
+		previous_hash: Option<Hash>,
+		items: Vec<ArchiveStorageDiffItem<String>>,
+	) -> RpcResult<ArchiveStorageDiffMethodResult>;
 }

substrate/client/rpc-spec-v2/src/archive/archive.rs

@@ -19,8 +19,15 @@
 //! API implementation for `archive`.
 
 use crate::{
-	archive::{error::Error as ArchiveError, ArchiveApiServer},
-	common::events::{ArchiveStorageResult, PaginatedStorageQuery},
+	archive::{
+		archive_storage::{ArchiveStorage, ArchiveStorageDiff},
+		error::Error as ArchiveError,
+		ArchiveApiServer,
+	},
+	common::events::{
+		ArchiveStorageDiffItem, ArchiveStorageDiffMethodResult, ArchiveStorageResult,
+		PaginatedStorageQuery,
+	},
 	hex_string, MethodResult,
 };
 
@@ -41,8 +48,6 @@ use sp_runtime::{
 };
 use std::{collections::HashSet, marker::PhantomData, sync::Arc};
 
-use super::archive_storage::ArchiveStorage;
-
 /// The configuration of [`Archive`].
 pub struct ArchiveConfig {
 	/// The maximum number of items the `archive_storage` can return for a descendant query before
@@ -278,4 +283,42 @@ where
 
 		Ok(storage_client.handle_query(hash, items, child_trie))
 	}
+
+	fn archive_unstable_storage_diff(
+		&self,
+		hash: Block::Hash,
+		previous_hash: Option<Block::Hash>,
+		items: Vec<ArchiveStorageDiffItem<String>>,
+	) -> RpcResult<ArchiveStorageDiffMethodResult> {
+		let storage_client = ArchiveStorageDiff::new(self.client.clone());
+
+		// Deduplicate the items.
+		let trie_items = storage_client.deduplicate_items(items)?;
+
+		let previous_hash = if let Some(previous_hash) = previous_hash {
+			previous_hash
+		} else {
+			let Ok(Some(current_header)) = self.client.header(hash) else {
+				return Err(ArchiveError::InvalidParam(format!(
+					"Block header is not present: {}",
+					hash
+				))
+				.into());
+			};
+			*current_header.parent_hash()
+		};
+
+		if trie_items.is_empty() {
+			let result = storage_client.handle_trie_queries(hash, previous_hash, Vec::new())?;
+			return Ok(ArchiveStorageDiffMethodResult { result })
+		}
+
+		let mut storage_results = Vec::new();
+		for trie_queries in trie_items {
+			let result = storage_client.handle_trie_queries(hash, previous_hash, trie_queries)?;
+			storage_results.extend(result);
+		}
+
+		Ok(ArchiveStorageDiffMethodResult { result: storage_results })
+	}
 }