homework5

gistfile1.txt

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

// a module for proof of existence
pub use pallet::*;

#[frame_support::pallet]
pub mod pallet {
	use frame_support::{dispatch::DispatchResultWithPostInfo, pallet_prelude::*};
	use frame_system::pallet_prelude::*;
	use sp_std::vec::Vec;
	#[pallet::config]
	pub trait Config: frame_system::Config {
		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
	}

	#[pallet::pallet]
	#[pallet::generate_store(pub(super) trait Store)]
	pub struct Pallet<T>(_);

	#[pallet::storage]
	#[pallet::getter(fn proofs)]
	pub type Proofs<T: Config> = StorageMap<_, Blake2_128Concat, Vec<u8>, (T::AccountId, T::BlockNumber)>;


	#[pallet::event]
	#[pallet::metadata(T::AccountId = "AccountId")]
	#[pallet::generate_deposit(pub(super) fn deposit_event)]
	pub enum Event<T:Config> {
		ClaimCreated(T::AccountId, Vec<u8>),
		ClaimRevoked(T::AccountId, Vec<u8>),
		TransferClaim(Vec<u8>, T::AccountId),
	}

	#[pallet::error]
	pub enum Error<T>{
		ProofAlreadyExist,
		ClaimNotExist,
		NotClaimOwner,
	}

	#[pallet::hooks]
	impl<T: Config>Hooks<BlockNumberFor<T>> for Pallet<T>{}

	#[pallet::call]
	impl<T:Config> Pallet<T> {
		#[pallet::weight(0)]
		pub fn create_claim(
			origin: OriginFor<T>,
			claim: Vec<u8>
		) -> DispatchResultWithPostInfo {
			let sender = ensure_signed(origin)?;
			ensure!(!Proofs::<T>::contains_key(&claim), Error::<T>::ProofAlreadyExist);
			Proofs::<T>::insert(
				&claim,
				(sender.clone(), frame_system::Pallet::<T>::block_number())
			);
			Self::deposit_event(Event::ClaimCreated(sender, claim));
			Ok(().into())
		}

		#[pallet::weight(0)]
		pub fn revoke_claim(
			origin: OriginFor<T>,
			claim: Vec<u8>
		) -> DispatchResultWithPostInfo {
			let sender = ensure_signed(origin)?;
			let (owner, _) = Proofs::<T>::get(&claim).ok_or(Error::<T>::ClaimNotExist)?;
			ensure!(owner == sender, Error::<T>::NotClaimOwner);
			Proofs::<T>::remove(&claim);
			Self::deposit_event(Event::ClaimRevoked(sender, claim));
			Ok(().into())
		}

		#[pallet::weight(0)]
		pub fn transfer_claim(
			origin: OriginFor<T>,
			claim: Vec<u8>,
			recviever: T::AccountId,
		) -> DispatchResultWithPostInfo {

			let sender = ensure_signed(origin)?;
			let (owner, _) = Proofs::<T>::get(&claim).ok_or(Error::<T>::ClaimNotExist)?;
			ensure!(owner == sender, Error::<T>::NotClaimOwner);
			Proofs::<T>::remove(&claim);
			let current_block = frame_system::Pallet::<T>::block_number();
			Proofs::<T>::insert(&claim, (recviever.clone(), current_block));
			Self::deposit_event(Event::TransferClaim(claim, recviever.clone()));
			Ok(().into())
		}
	}
}