refactor: build chain extension method

pop-api/src/lib.rs

@@ -1,6 +1,6 @@
 #![cfg_attr(not(feature = "std"), no_std, no_main)]
 
-use ink::env::chain_extension::FromStatusCode;
+use ink::env::chain_extension::{ChainExtensionMethod, FromStatusCode};
 
 use constants::DECODING_FAILED;
 
@@ -33,6 +33,22 @@ mod constants {
 	pub(crate) const BALANCES: u8 = 10;
 }
 
+/// Helper method to build `ChainExtensionMethod`.
+///
+/// Parameters:
+/// - 'version': The version of the chain extension
+/// - 'function': The ID of the function
+/// - 'module': The index of the runtime module
+/// - 'dispatchable': The index of the module dispatchable functions
+fn build_extension_method(
+	version: u8,
+	function: u8,
+	module: u8,
+	dispatchable: u8,
+) -> ChainExtensionMethod<(), (), (), false> {
+	ChainExtensionMethod::build(u32::from_le_bytes([version, function, module, dispatchable]))
+}
+
 /// Represents a status code returned by the runtime.
 ///
 /// `StatusCode` encapsulates a `u32` value that indicates the status of an operation performed

pop-api/src/v0/assets/mod.rs

@@ -1,9 +1,8 @@
-use ink::{env::chain_extension::ChainExtensionMethod, prelude::vec::Vec, scale::Decode};
+use ink::{prelude::vec::Vec, scale::Decode};
 
 use crate::{
-	constants::{ASSETS, DECODING_FAILED, DISPATCH, READ_STATE},
+	constants::{ASSETS, DECODING_FAILED},
 	primitives::{AccountId, AssetId, Balance},
-	v0::V0,
 	Result, StatusCode,
 };
 
@@ -33,6 +32,22 @@ const CANCEL_APPROVAL: u8 = 23;
 /// - transfer_approved
 const TRANSFER_APPROVED: u8 = 25;
 
+/// Helper method to build a dispatch call `ChainExtensionMethod` for `ASSET` module
+///
+/// Parameters:
+/// - 'dispatchable': The index of the dispatchable functions in `ASSET` module.
+fn build_dispatch(dispatchable: u8) -> ChainExtensionMethod<(), (), (), false> {
+	crate::v0::build_dispatch(ASSETS, dispatchable)
+}
+
+/// Helper method to build a dispatch call `ChainExtensionMethod` for `ASSET` module
+///
+/// Parameters:
+/// - 'state_query': The index of the runtime state query.
+fn build_read_state(state_query: u8) -> ChainExtensionMethod<(), (), (), false> {
+	crate::v0::build_read_state(ASSETS, state_query)
+}
+
 /// Issue a new class of fungible assets from a public origin.
 // pub(crate) fn create(
 // 	id: AssetId,
@@ -91,17 +106,12 @@ const TRANSFER_APPROVED: u8 = 25;
 /// Move some assets from the sender account to another, keeping the sender account alive.
 #[inline]
 pub fn transfer_keep_alive(id: AssetId, target: AccountId, amount: Balance) -> Result<()> {
-	ChainExtensionMethod::build(u32::from_le_bytes([
-		V0,
-		DISPATCH,
-		ASSETS,
-		// E.D. is always respected with transferring tokens via the API.
-		TRANSFER_KEEP_ALIVE,
-	]))
-	.input::<(AssetId, AccountId, Balance)>()
-	.output::<Result<()>, true>()
-	.handle_error_code::<StatusCode>()
-	.call(&(id, target, amount))
+	// E.D. is always respected with transferring tokens via the API.
+	build_dispatch(TRANSFER_KEEP_ALIVE)
+		.input::<(AssetId, AccountId, Balance)>()
+		.output::<Result<()>, true>()
+		.handle_error_code::<StatusCode>()
+		.call(&(id, target, amount))
 }
 
 // /// Set the metadata for an asset.
@@ -122,7 +132,7 @@ pub fn transfer_keep_alive(id: AssetId, target: AccountId, amount: Balance) -> R
 /// Approve an amount of asset for transfer by a delegated third-party account.
 #[inline]
 pub fn approve_transfer(id: AssetId, delegate: AccountId, amount: Balance) -> Result<()> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, DISPATCH, ASSETS, APPROVE_TRANSFER]))
+	build_dispatch(APPROVE_TRANSFER)
 		.input::<(AssetId, AccountId, Balance)>()
 		.output::<Result<()>, true>()
 		.handle_error_code::<StatusCode>()
@@ -132,7 +142,7 @@ pub fn approve_transfer(id: AssetId, delegate: AccountId, amount: Balance) -> Re
 /// Cancel all of some asset approved for delegated transfer by a third-party account.
 #[inline]
 pub fn cancel_approval(id: AssetId, delegate: AccountId) -> Result<()> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, DISPATCH, ASSETS, CANCEL_APPROVAL]))
+	build_dispatch(CANCEL_APPROVAL)
 		.input::<(AssetId, AccountId)>()
 		.output::<Result<()>, true>()
 		.handle_error_code::<StatusCode>()
@@ -148,7 +158,7 @@ pub fn transfer_approved(
 	to: AccountId,
 	amount: Balance,
 ) -> Result<()> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, DISPATCH, ASSETS, TRANSFER_APPROVED]))
+	build_dispatch(TRANSFER_APPROVED)
 		.input::<(AssetId, AccountId, AccountId, Balance)>()
 		.output::<Result<()>, true>()
 		.handle_error_code::<StatusCode>()
@@ -172,7 +182,7 @@ const TOKEN_DECIMALS: u8 = 5;
 
 #[inline]
 pub fn total_supply(id: AssetId) -> Result<Balance> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, READ_STATE, ASSETS, TOTAL_SUPPLY]))
+	build_read_state(TOTAL_SUPPLY)
 		.input::<AssetId>()
 		.output::<Result<Vec<u8>>, true>()
 		.handle_error_code::<StatusCode>()
@@ -182,7 +192,7 @@ pub fn total_supply(id: AssetId) -> Result<Balance> {
 
 #[inline]
 pub fn balance_of(id: AssetId, owner: AccountId) -> Result<Balance> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, READ_STATE, ASSETS, BALANCE_OF]))
+	build_read_state(ASSETS, BALANCE_OF)
 		.input::<(AssetId, AccountId)>()
 		.output::<Result<Vec<u8>>, true>()
 		.handle_error_code::<StatusCode>()
@@ -192,7 +202,7 @@ pub fn balance_of(id: AssetId, owner: AccountId) -> Result<Balance> {
 
 #[inline]
 pub fn allowance(id: AssetId, owner: AccountId, spender: AccountId) -> Result<Balance> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, READ_STATE, ASSETS, ALLOWANCE]))
+	build_read_state(ALLOWANCE)
 		.input::<(AssetId, AccountId, AccountId)>()
 		.output::<Result<Vec<u8>>, true>()
 		.handle_error_code::<StatusCode>()
@@ -202,7 +212,7 @@ pub fn allowance(id: AssetId, owner: AccountId, spender: AccountId) -> Result<Ba
 
 #[inline]
 pub fn token_name(id: AssetId) -> Result<Vec<u8>> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, READ_STATE, ASSETS, TOKEN_NAME]))
+	build_read_state(TOKEN_NAME)
 		.input::<AssetId>()
 		.output::<Result<Vec<u8>>, true>()
 		.handle_error_code::<StatusCode>()
@@ -212,7 +222,7 @@ pub fn token_name(id: AssetId) -> Result<Vec<u8>> {
 //
 #[inline]
 pub fn token_symbol(id: AssetId) -> Result<Vec<u8>> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, READ_STATE, ASSETS, TOKEN_SYMBOL]))
+	build_read_state(TOKEN_SYMBOL)
 		.input::<AssetId>()
 		.output::<Result<Vec<u8>>, true>()
 		.handle_error_code::<StatusCode>()
@@ -222,7 +232,7 @@ pub fn token_symbol(id: AssetId) -> Result<Vec<u8>> {
 
 #[inline]
 pub fn token_decimals(id: AssetId) -> Result<u8> {
-	ChainExtensionMethod::build(u32::from_le_bytes([V0, READ_STATE, ASSETS, TOKEN_DECIMALS]))
+	build_read_state(TOKEN_DECIMALS)
 		.input::<AssetId>()
 		.output::<Result<Vec<u8>>, true>()
 		.handle_error_code::<StatusCode>()

pop-api/src/v0/mod.rs

@@ -1,4 +1,10 @@
-use crate::{primitives::error::Error, StatusCode};
+use crate::{
+	build_extension_method,
+	constants::{DISPATCH, READ_STATE},
+	primitives::error::Error,
+	StatusCode,
+};
+use ink::env::chain_extension::ChainExtensionMethod;
 
 #[cfg(feature = "assets")]
 pub mod assets;
@@ -16,3 +22,35 @@ impl From<StatusCode> for Error {
 		value.0.into()
 	}
 }
+
+/// Helper method to build `ChainExtensionMethod` for version `v0`
+///
+/// Parameters:
+/// - 'function': The ID of the function
+/// - 'module': The index of the runtime module
+/// - 'dispatchable': The index of the module dispatchable functions
+fn build_extension_method_v0(
+	function: u8,
+	module: u8,
+	dispatchable: u8,
+) -> ChainExtensionMethod<(), (), (), false> {
+	build_extension_method(V0, function, module, dispatchable)
+}
+
+/// Helper method to build a dispatch call `ChainExtensionMethod`
+///
+/// Parameters:
+/// - 'module': The index of the runtime module
+/// - 'dispatchable': The index of the module dispatchable functions
+fn build_dispatch(module: u8, dispatchable: u8) -> ChainExtensionMethod<(), (), (), false> {
+	build_extension_method_v0(DISPATCH, module, dispatchable)
+}
+
+/// Helper method to build a dispatch call `ChainExtensionMethod`
+///
+/// Parameters:
+/// - 'module': The index of the runtime module
+/// - 'state_query': The index of the runtime state query
+fn build_read_state(module: u8, state_query: u8) -> ChainExtensionMethod<(), (), (), false> {
+	build_extension_method_v0(READ_STATE, module, state_query)
+}