pezkuwi-subxt-core 0.44.0

// Copyright 2019-2024 Parity Technologies (UK) Ltd.
// This file is dual-licensed as Apache-2.0 or GPL-3.0.
// see LICENSE for license details.

//! Encode View Function payloads, decode the associated values returned from them, and validate
//! static View Function payloads.

pub mod payload;

use crate::{error::ViewFunctionError, Metadata};
use alloc::{string::ToString, vec::Vec};
use payload::Payload;
use scale_decode::IntoVisitor;

/// Run the validation logic against some View Function payload you'd like to use. Returns `Ok(())`
/// if the payload is valid (or if it's not possible to check since the payload has no validation
/// hash). Return an error if the payload was not valid or something went wrong trying to validate
/// it (ie the View Function in question do not exist at all)
pub fn validate<P: Payload>(payload: P, metadata: &Metadata) -> Result<(), ViewFunctionError> {
	let Some(hash) = payload.validation_hash() else {
		return Ok(());
	};

	let pallet_name = payload.pallet_name();
	let function_name = payload.function_name();

	let view_function = metadata
		.pallet_by_name(pallet_name)
		.ok_or_else(|| ViewFunctionError::PalletNotFound(pallet_name.to_string()))?
		.view_function_by_name(function_name)
		.ok_or_else(|| ViewFunctionError::ViewFunctionNotFound {
			pallet_name: pallet_name.to_string(),
			function_name: function_name.to_string(),
		})?;

	if hash != view_function.hash() {
		Err(ViewFunctionError::IncompatibleCodegen)
	} else {
		Ok(())
	}
}

/// The name of the Runtime API call which can execute
pub const CALL_NAME: &str = "RuntimeViewFunction_execute_view_function";

/// Encode the bytes that will be passed to the "execute_view_function" Runtime API call,
/// to execute the View Function represented by the given payload.
pub fn call_args<P: Payload>(
	payload: P,
	metadata: &Metadata,
) -> Result<Vec<u8>, ViewFunctionError> {
	let inputs = frame_decode::view_functions::encode_view_function_inputs(
		payload.pallet_name(),
		payload.function_name(),
		payload.args(),
		metadata,
		metadata.types(),
	)
	.map_err(ViewFunctionError::CouldNotEncodeInputs)?;

	Ok(inputs)
}

/// Decode the value bytes at the location given by the provided View Function payload.
pub fn decode_value<P: Payload>(
	bytes: &mut &[u8],
	payload: P,
	metadata: &Metadata,
) -> Result<P::ReturnType, ViewFunctionError> {
	let value = frame_decode::view_functions::decode_view_function_response(
		payload.pallet_name(),
		payload.function_name(),
		bytes,
		metadata,
		metadata.types(),
		P::ReturnType::into_visitor(),
	)
	.map_err(ViewFunctionError::CouldNotDecodeResponse)?;

	Ok(value)
}