lib.rs

#![cfg_attr(not(feature = "std"), no_std)]

use orml_traits::{DataProvider, PriceProvider};
use palette_support::{decl_module, decl_storage, Parameter};
use sr_primitives::traits::{MaybeSerializeDeserialize, Member, SimpleArithmetic, Zero};

pub trait Trait: palette_system::Trait {
	type CurrencyId: Parameter + Member + Default + Copy + MaybeSerializeDeserialize;
	type Price: Parameter + Member + Zero + SimpleArithmetic + Copy + Ord;
	type Source: DataProvider<Self::CurrencyId, Self::Price>;
}

mod mock;
mod tests;

decl_storage! {
	trait Store for Module<T: Trait> as Prices { }
}

decl_module! {
	pub struct Module<T: Trait> for enum Call where origin: T::Origin { }
}

impl<T: Trait> Module<T> {}

impl<T: Trait> PriceProvider<T::CurrencyId, T::Price> for Module<T> {
	fn get_price(base: T::CurrencyId, quote: T::CurrencyId) -> Option<T::Price> {
		if let (Some(base_price), Some(quote_price)) = (T::Source::get(&base), (T::Source::get(&quote))) {
			if !base_price.is_zero() {
				return Some(quote_price / base_price);
			}
		}

		None
	}
}