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// Copyright 2018-2020 Parity Technologies (UK) Ltd.
// This file is part of cargo-contract.
//
// cargo-contract is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// cargo-contract is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with cargo-contract. If not, see <http://www.gnu.org/licenses/>.
use super::scon::Value;
use anyhow::{
Context,
Result,
};
use scale::{
Decode,
Encode,
Output,
};
use scale_info::{
form::PortableForm,
IntoPortable,
Path,
TypeInfo,
};
use sp_core::crypto::{
AccountId32,
Ss58Codec,
};
use std::{
boxed::Box,
collections::HashMap,
convert::TryFrom,
str::FromStr,
};
/// Provides custom encoding and decoding for predefined environment types.
#[derive(Default)]
pub struct EnvTypesTranscoder {
transcoders: HashMap<u32, Box<dyn CustomTypeTranscoder>>,
}
impl EnvTypesTranscoder {
/// Construct an `EnvTypesTranscoder` from the given type registry.
pub fn new(transcoders: HashMap<u32, Box<dyn CustomTypeTranscoder>>) -> Self {
Self { transcoders }
}
/// If the given type id is for a type with custom encoding, encodes the given value with the
/// custom encoder and returns `true`. Otherwise returns `false`.
///
/// # Errors
///
/// - If the custom encoding fails.
pub fn try_encode<O>(
&self,
type_id: u32,
value: &Value,
output: &mut O,
) -> Result<bool>
where
O: Output,
{
match self.transcoders.get(&type_id) {
Some(transcoder) => {
log::debug!("Encoding type {:?} with custom encoder", type_id);
let encoded_env_type = transcoder
.encode_value(value)
.context("Error encoding custom type")?;
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output.write(&encoded_env_type);
Ok(true)
}
None => Ok(false),
}
}
/// If the given type lookup id is for an environment type with custom
/// decoding, decodes the given input with the custom decoder and returns
/// `Some(value)`. Otherwise returns `None`.
///
/// # Errors
///
/// - If the custom decoding fails.
pub fn try_decode(&self, type_id: u32, input: &mut &[u8]) -> Result<Option<Value>> {
match self.transcoders.get(&type_id) {
Some(transcoder) => {
log::debug!("Decoding type {:?} with custom decoder", type_id);
let decoded = transcoder.decode_value(input)?;
Ok(Some(decoded))
}
None => {
log::debug!("No custom decoder found for type {:?}", type_id);
Ok(None)
}
}
}
}
/// Implement this trait to define custom transcoding for a type in a `scale-info` type registry.
pub trait CustomTypeTranscoder {
fn aliases(&self) -> &[&str];
fn encode_value(&self, value: &Value) -> Result<Vec<u8>>;
fn decode_value(&self, input: &mut &[u8]) -> Result<Value>;
}
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub struct PathKey(Vec<String>);
impl PathKey {
pub fn from_type<T>() -> Self
where
T: TypeInfo,
{
let type_info = T::type_info();
let path = type_info
.path()
.clone()
.into_portable(&mut Default::default());
PathKey::from(&path)
}
}
impl From<&Path<PortableForm>> for PathKey {
fn from(path: &Path<PortableForm>) -> Self {
PathKey(path.segments().to_vec())
}
}
pub type TypesByPath = HashMap<PathKey, u32>;
pub struct AccountId;
impl CustomTypeTranscoder for AccountId {
fn aliases(&self) -> &[&'static str] {
&["AccountId"]
}
fn encode_value(&self, value: &Value) -> Result<Vec<u8>> {
let account_id = match value {
Value::Literal(literal) => {
AccountId32::from_str(literal).map_err(|e| {
anyhow::anyhow!(
"Error parsing AccountId from literal `{}`: {}",
literal,
e
)
})?
}
Value::String(string) => {
AccountId32::from_str(string).map_err(|e| {
anyhow::anyhow!(
"Error parsing AccountId from string '{}': {}",
string,
e
)
})?
}
Value::Hex(hex) => {
AccountId32::try_from(hex.bytes()).map_err(|_| {
anyhow::anyhow!(
"Error converting hex bytes `{:?}` to AccountId",
hex.bytes()
)
_ => {
return Err(anyhow::anyhow!(
"Expected a string or a literal for an AccountId"
))
}
};
Ok(account_id.encode())
}
fn decode_value(&self, input: &mut &[u8]) -> Result<Value> {
let account_id = AccountId32::decode(input)?;
Ok(Value::Literal(account_id.to_ss58check()))
}
}