Add sponsored transaction mechanism to Cis2_multi contract

examples/README.md

@@ -23,8 +23,7 @@ The list of contracts is as follows:
   mimic the memo feature. Normally a transfer between accounts cannot add any
   information other than the amount being transferred. Making transfers to this
   intermediate contract instead works around this limitation.
-- [cis2-multi](./cis2-multi) An example implementation of the CIS-2 Concordium Token Standard
-  containing multiple token types.
+- [cis2-multi](./cis2-multi) An example implementation of the CIS-2 Concordium Token Standard and CIS-3 Concordium Sponsored Transaction Standard containing multiple token types.
 - [cis2-multi-royalties](./cis2-multi-royalties) An example implementation of the CIS-2 Concordium Token Standard which allows the token minter to be paid royalties
   containing multiple token types.
 - [cis2-nft](./cis2-nft) An example implementation of the CIS-2 Concordium Token Standard

examples/auction/tests/tests.rs

@@ -252,7 +252,7 @@ fn initialize_chain_and_auction() -> (Chain, ContractAddress) {
         .build()
         .expect("Exchange rate is in valid range");
 
-    // Create some accounts accounts on the chain.
+    // Create some accounts on the chain.
     chain.create_account(Account::new(ALICE, ACC_INITIAL_BALANCE));
     chain.create_account(Account::new(BOB, ACC_INITIAL_BALANCE));
     chain.create_account(Account::new(CAROL, ACC_INITIAL_BALANCE));

examples/cis2-multi-royalties/src/lib.rs

@@ -165,8 +165,6 @@ pub enum CustomContractError {
     LogFull,
     /// Failed logging: Log is malformed.
     LogMalformed,
-    /// Invalid contract name.
-    InvalidContractName,
     /// Only a smart contract can call this function.
     ContractOnly,
     /// Failed to invoke a contract.
@@ -209,10 +207,6 @@ impl From<CustomContractError> for ContractError {
     fn from(c: CustomContractError) -> Self { Cis2Error::Custom(c) }
 }
 
-impl From<NewReceiveNameError> for CustomContractError {
-    fn from(_: NewReceiveNameError) -> Self { Self::InvalidContractName }
-}
-
 impl State {
     /// Construct a state with no tokens
     fn empty(state_builder: &mut StateBuilder, pay_royalty: bool) -> Self {
@@ -291,7 +285,7 @@ impl State {
         }
         // Get the `from` state and balance, if not present it will fail since the
         // balance is interpreted as 0 and the transfer amount must be more than
-        // 0 as this point.;
+        // 0 at this point.
         {
             let mut from_address_state =
                 self.state.entry(*from).occupied_or(ContractError::InsufficientFunds)?;
@@ -813,7 +807,7 @@ fn contract_on_cis2_received(ctx: &ReceiveContext, host: &Host<State>) -> Contra
     host.invoke_contract_read_only(
         &sender,
         &parameter,
-        EntrypointName::new("transfer")?,
+        EntrypointName::new_unchecked("transfer"),
         Amount::zero(),
     )?;
     Ok(())

examples/cis2-multi/Cargo.toml

@@ -16,6 +16,7 @@ concordium-cis2 = {path = "../../concordium-cis2", default-features = false}
 
 [dev-dependencies]
 concordium-smart-contract-testing = {path = "../../contract-testing"}
+rand = "0.7.0"
 
 [lib]
 crate-type=["cdylib", "rlib"]