Less slices (#9176)

* Less slices

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/client/executor/common/src/sandbox.rs

@@ -187,10 +187,10 @@ fn trap(msg: &'static str) -> Trap {
 	TrapKind::Host(Box::new(Error::Other(msg.into()))).into()
 }
 
-fn deserialize_result(serialized_result: &[u8]) -> std::result::Result<Option<RuntimeValue>, Trap> {
+fn deserialize_result(mut serialized_result: &[u8]) -> std::result::Result<Option<RuntimeValue>, Trap> {
 	use self::sandbox_primitives::HostError;
 	use sp_wasm_interface::ReturnValue;
-	let result_val = std::result::Result::<ReturnValue, HostError>::decode(&mut &serialized_result[..])
+	let result_val = std::result::Result::<ReturnValue, HostError>::decode(&mut serialized_result)
 		.map_err(|_| trap("Decoding Result<ReturnValue, HostError> failed!"))?;
 
 	match result_val {
@@ -379,10 +379,10 @@ pub enum InstantiationError {
 }
 
 fn decode_environment_definition(
-	raw_env_def: &[u8],
+	mut raw_env_def: &[u8],
 	memories: &[Option<MemoryRef>],
 ) -> std::result::Result<(Imports, GuestToSupervisorFunctionMapping), InstantiationError> {
-	let env_def = sandbox_primitives::EnvironmentDefinition::decode(&mut &raw_env_def[..])
+	let env_def = sandbox_primitives::EnvironmentDefinition::decode(&mut raw_env_def)
 		.map_err(|_| InstantiationError::EnvironmentDefinitionCorrupted)?;
 
 	let mut func_map = HashMap::new();

substrate/client/executor/src/wasm_runtime.rs

@@ -177,7 +177,7 @@ impl RuntimeCache {
 
 	/// Prepares a WASM module instance and executes given function for it.
 	///
-	/// This uses internal cache to find avaiable instance or create a new one.
+	/// This uses internal cache to find available instance or create a new one.
 	/// # Parameters
 	///
 	/// `code` - Provides external code or tells the executor to fetch it from storage.
@@ -196,7 +196,7 @@ impl RuntimeCache {
 	///
 	/// `f` - Function to execute.
 	///
-	/// # Returns result of `f` wrapped in an additonal result.
+	/// # Returns result of `f` wrapped in an additional result.
 	/// In case of failure one of two errors can be returned:
 	///
 	/// `Err::InvalidCode` is returned for runtime code issues.
@@ -337,7 +337,7 @@ pub fn create_wasm_runtime_with_code(
 	}
 }
 
-fn decode_version(version: &[u8]) -> Result<RuntimeVersion, WasmError> {
+fn decode_version(mut version: &[u8]) -> Result<RuntimeVersion, WasmError> {
 	let v: RuntimeVersion = sp_api::OldRuntimeVersion::decode(&mut &version[..])
 		.map_err(|_|
 				 WasmError::Instantiation(
@@ -347,7 +347,7 @@ fn decode_version(version: &[u8]) -> Result<RuntimeVersion, WasmError> {
 
 	let core_api_id = sp_core::hashing::blake2_64(b"Core");
 	if v.has_api_with(&core_api_id, |v| v >= 3) {
-		sp_api::RuntimeVersion::decode(&mut &version[..])
+		sp_api::RuntimeVersion::decode(&mut version)
 			.map_err(|_|
 				WasmError::Instantiation("failed to decode \"Core_version\" result".into())
 			)
@@ -367,9 +367,7 @@ fn decode_runtime_apis(apis: &[u8]) -> Result<Vec<([u8; 8], u32)>, WasmError> {
 			<[u8; RUNTIME_API_INFO_SIZE]>::try_from(chunk)
 				.map(sp_api::deserialize_runtime_api_info)
 				.map_err(|_| {
-					WasmError::Other(format!(
-						"a clipped runtime api info declaration"
-					))
+					WasmError::Other("a clipped runtime api info declaration".to_owned())
 				})
 		})
 		.collect::<Result<Vec<_>, WasmError>>()
@@ -383,15 +381,15 @@ fn decode_runtime_apis(apis: &[u8]) -> Result<Vec<([u8; 8], u32)>, WasmError> {
 pub fn read_embedded_version(
 	blob: &RuntimeBlob,
 ) -> Result<Option<RuntimeVersion>, WasmError> {
-	if let Some(version_section) = blob.custom_section_contents("runtime_version") {
+	if let Some(mut version_section) = blob.custom_section_contents("runtime_version") {
 		// We do not use `decode_version` here because the runtime_version section is not supposed
 		// to ever contain a legacy version. Apart from that `decode_version` relies on presence
 		// of a special API in the `apis` field to treat the input as a non-legacy version. However
 		// the structure found in the `runtime_version` always contain an empty `apis` field. Therefore
-		// the version read will be mistakingly treated as an legacy one.
-		let mut decoded_version = sp_api::RuntimeVersion::decode(&mut &version_section[..])
+		// the version read will be mistakenly treated as an legacy one.
+		let mut decoded_version = sp_api::RuntimeVersion::decode(&mut version_section)
 			.map_err(|_|
-				WasmError::Instantiation("failed to decode verison section".into())
+				WasmError::Instantiation("failed to decode version section".into())
 			)?;
 
 		// Don't stop on this and check if there is a special section that encodes all runtime APIs.

substrate/client/executor/wasmi/src/lib.rs

@@ -185,7 +185,7 @@ impl<'a> Sandbox for FunctionExecutor<'a> {
 		&mut self,
 		instance_id: u32,
 		export_name: &str,
-		args: &[u8],
+		mut args: &[u8],
 		return_val: Pointer<u8>,
 		return_val_len: WordSize,
 		state: u32,
@@ -193,7 +193,7 @@ impl<'a> Sandbox for FunctionExecutor<'a> {
 		trace!(target: "sp-sandbox", "invoke, instance_idx={}", instance_id);
 
 		// Deserialize arguments and convert them into wasmi types.
-		let args = Vec::<sp_wasm_interface::Value>::decode(&mut &args[..])
+		let args = Vec::<sp_wasm_interface::Value>::decode(&mut args)
 			.map_err(|_| "Can't decode serialized arguments for the invocation")?
 			.into_iter()
 			.map(Into::into)