burn implemented

Co-authored-by: igor-casper <[email protected]>

execution_engine/src/runtime/mint_internal.rs

@@ -97,6 +97,10 @@ where
                 ProviderError::AddressableEntityByAccountHash(account_hash)
             })
     }
+
+    fn is_valid_uref(&self, uref: &URef) -> bool {
+        self.context.access_rights().has_access_rights_to_uref(uref)
+    }
 }
 
 // TODO: update Mint + StorageProvider to better handle errors

execution_engine/src/runtime/mod.rs

@@ -609,6 +609,14 @@ where
                 let result: Result<(), mint::Error> = mint_runtime.reduce_total_supply(amount);
                 CLValue::from_t(result).map_err(Self::reverter)
             })(),
+            mint::METHOD_BURN => (|| {
+                mint_runtime.charge_system_contract_call(mint_costs.burn)?;
+
+                let purse: URef = Self::get_named_argument(runtime_args, mint::ARG_PURSE)?;
+                let amount: U512 = Self::get_named_argument(runtime_args, mint::ARG_AMOUNT)?;
+                let result: Result<(), mint::Error> = mint_runtime.burn(purse, amount);
+                CLValue::from_t(result).map_err(Self::reverter)
+            })(),
             // Type: `fn create() -> URef`
             mint::METHOD_CREATE => (|| {
                 mint_runtime.charge_system_contract_call(mint_costs.create)?;

execution_engine/src/runtime_context/mod.rs

@@ -669,7 +669,7 @@ where
     }
 
     /// Validates whether keys used in the `value` are not forged.
-    fn validate_value(&self, value: &StoredValue) -> Result<(), ExecError> {
+    pub(crate) fn validate_value(&self, value: &StoredValue) -> Result<(), ExecError> {
         match value {
             StoredValue::CLValue(cl_value) => self.validate_cl_value(cl_value),
             StoredValue::Account(_) => Ok(()),
@@ -743,7 +743,7 @@ where
     }
 
     /// Validates if a [`Key`] refers to a [`URef`] and has a write bit set.
-    fn validate_writeable(&self, key: &Key) -> Result<(), ExecError> {
+    pub(crate) fn validate_writeable(&self, key: &Key) -> Result<(), ExecError> {
         if self.is_writeable(key) {
             Ok(())
         } else {

execution_engine_testing/tests/src/test/system_contracts/mint.rs

@@ -0,0 +1,216 @@
+use casper_engine_test_support::{
+    auction, ExecuteRequestBuilder, LmdbWasmTestBuilder, DEFAULT_ACCOUNT_ADDR,
+};
+use casper_types::{runtime_args, ProtocolVersion, URef, U512};
+
+use tempfile::TempDir;
+
+const TEST_DELEGATOR_INITIAL_ACCOUNT_BALANCE: u64 = 1_000_000 * 1_000_000_000;
+
+const CONTRACT_BURN: &str = "burn.wasm";
+const CONTRACT_TRANSFER_TO_NAMED_PURSE: &str = "transfer_to_named_purse.wasm";
+
+const ARG_AMOUNT: &str = "amount";
+
+const ARG_PURSE_NAME: &str = "purse_name";
+
+#[ignore]
+#[test]
+fn should_empty_purse_when_burning_above_balance() {
+    let data_dir = TempDir::new().expect("should create temp dir");
+    let mut builder = LmdbWasmTestBuilder::new(data_dir.as_ref());
+    let source = *DEFAULT_ACCOUNT_ADDR;
+
+    let delegator_keys = auction::generate_public_keys(1);
+    let validator_keys = auction::generate_public_keys(1);
+
+    auction::run_genesis_and_create_initial_accounts(
+        &mut builder,
+        &validator_keys,
+        delegator_keys
+            .iter()
+            .map(|public_key| public_key.to_account_hash())
+            .collect::<Vec<_>>(),
+        U512::from(TEST_DELEGATOR_INITIAL_ACCOUNT_BALANCE),
+    );
+
+    let initial_supply = builder.total_supply(None);
+    let purse_name = "purse";
+    let purse_amount = U512::from(10_000_000_000u64);
+
+    // Create purse and transfer tokens to it
+    let exec_request = ExecuteRequestBuilder::standard(
+        source,
+        CONTRACT_TRANSFER_TO_NAMED_PURSE,
+        runtime_args! {
+            ARG_PURSE_NAME => purse_name,
+            ARG_AMOUNT => purse_amount,
+        },
+    )
+    .build();
+
+    builder.exec(exec_request).expect_success().commit();
+
+    let account = builder
+        .get_entity_with_named_keys_by_account_hash(source)
+        .expect("should have account");
+
+    let purse_uref: URef = account
+        .named_keys()
+        .get(purse_name)
+        .unwrap()
+        .into_uref()
+        .expect("should be uref");
+
+    assert_eq!(
+        builder
+            .get_purse_balance_result(ProtocolVersion::V2_0_0, purse_uref)
+            .motes()
+            .cloned()
+            .unwrap(),
+        purse_amount
+    );
+
+    // Burn part of tokens in a purse
+    let num_of_tokens_to_burn = U512::from(2_000_000_000u64);
+    let num_of_tokens_after_burn = U512::from(8_000_000_000u64);
+
+    let exec_request = ExecuteRequestBuilder::standard(
+        source,
+        CONTRACT_BURN,
+        runtime_args! {
+            ARG_PURSE_NAME => purse_name,
+            ARG_AMOUNT => num_of_tokens_to_burn,
+        },
+    )
+    .build();
+
+    builder.exec(exec_request).expect_success().commit();
+
+    assert_eq!(
+        builder
+            .get_purse_balance_result(ProtocolVersion::V2_0_0, purse_uref)
+            .motes()
+            .cloned()
+            .unwrap(),
+        num_of_tokens_after_burn
+    );
+
+    // Burn rest of tokens in a purse
+    let num_of_tokens_to_burn = U512::from(8_000_000_000u64);
+    let num_of_tokens_after_burn = U512::zero();
+
+    let exec_request = ExecuteRequestBuilder::standard(
+        source,
+        CONTRACT_BURN,
+        runtime_args! {
+            ARG_PURSE_NAME => purse_name,
+            ARG_AMOUNT => num_of_tokens_to_burn,
+        },
+    )
+    .build();
+
+    builder.exec(exec_request).expect_success().commit();
+
+    assert_eq!(
+        builder
+            .get_purse_balance_result(ProtocolVersion::V2_0_0, purse_uref)
+            .motes()
+            .cloned()
+            .unwrap(),
+        num_of_tokens_after_burn
+    );
+
+    let supply_after_burns = builder.total_supply(None);
+    let expected_supply_after_burns = initial_supply - U512::from(10_000_000_000u64);
+
+    assert_eq!(supply_after_burns, expected_supply_after_burns);
+}
+
+#[ignore]
+#[test]
+fn should_not_burn_excess_tokens() {
+    let data_dir = TempDir::new().expect("should create temp dir");
+    let mut builder = LmdbWasmTestBuilder::new(data_dir.as_ref());
+    let source = *DEFAULT_ACCOUNT_ADDR;
+
+    let delegator_keys = auction::generate_public_keys(1);
+    let validator_keys = auction::generate_public_keys(1);
+
+    auction::run_genesis_and_create_initial_accounts(
+        &mut builder,
+        &validator_keys,
+        delegator_keys
+            .iter()
+            .map(|public_key| public_key.to_account_hash())
+            .collect::<Vec<_>>(),
+        U512::from(TEST_DELEGATOR_INITIAL_ACCOUNT_BALANCE),
+    );
+
+    let initial_supply = builder.total_supply(None);
+    let purse_name = "purse";
+    let purse_amount = U512::from(10_000_000_000u64);
+
+    // Create purse and transfer tokens to it
+    let exec_request = ExecuteRequestBuilder::standard(
+        source,
+        CONTRACT_TRANSFER_TO_NAMED_PURSE,
+        runtime_args! {
+            ARG_PURSE_NAME => purse_name,
+            ARG_AMOUNT => purse_amount,
+        },
+    )
+    .build();
+
+    builder.exec(exec_request).expect_success().commit();
+
+    let account = builder
+        .get_entity_with_named_keys_by_account_hash(source)
+        .expect("should have account");
+
+    let purse_uref: URef = account
+        .named_keys()
+        .get(purse_name)
+        .unwrap()
+        .into_uref()
+        .expect("should be uref");
+
+    assert_eq!(
+        builder
+            .get_purse_balance_result(ProtocolVersion::V2_0_0, purse_uref)
+            .motes()
+            .cloned()
+            .unwrap(),
+        purse_amount
+    );
+
+    // Try to burn more then in a purse
+    let num_of_tokens_to_burn = U512::MAX;
+    let num_of_tokens_after_burn = U512::zero();
+
+    let exec_request = ExecuteRequestBuilder::standard(
+        source,
+        CONTRACT_BURN,
+        runtime_args! {
+            ARG_PURSE_NAME => purse_name,
+            ARG_AMOUNT => num_of_tokens_to_burn,
+        },
+    )
+    .build();
+
+    builder.exec(exec_request).expect_success().commit();
+
+    assert_eq!(
+        builder
+            .get_purse_balance_result(ProtocolVersion::V2_0_0, purse_uref)
+            .motes()
+            .cloned()
+            .unwrap(),
+        num_of_tokens_after_burn,
+    );
+
+    let supply_after_burns = builder.total_supply(None);
+    let expected_supply_after_burns = initial_supply - U512::from(10_000_000_000u64);
+
+    assert_eq!(supply_after_burns, expected_supply_after_burns);
+}

execution_engine_testing/tests/src/test/system_contracts/mod.rs

@@ -2,5 +2,6 @@ mod auction;
 mod auction_bidding;
 mod genesis;
 mod handle_payment;
+mod mint;
 mod standard_payment;
 mod upgrade;

resources/local/chainspec.toml.in

@@ -295,6 +295,7 @@ mint = 2_500_000_000
 reduce_total_supply = 10_000
 create = 2_500_000_000
 balance = 10_000
+burn = 10_000
 transfer = 10_000
 read_base_round_reward = 10_000
 mint_into_existing_purse = 2_500_000_000
@@ -313,4 +314,4 @@ pay = 10_000
 upper_threshold = 90
 lower_threshold = 50
 max_gas_price = 3
-min_gas_price = 1
+min_gas_price = 1

resources/production/chainspec.toml

@@ -306,6 +306,7 @@ mint = 2_500_000_000
 reduce_total_supply = 10_000
 create = 2_500_000_000
 balance = 10_000
+burn = 10_000
 transfer = 10_000
 read_base_round_reward = 10_000
 mint_into_existing_purse = 2_500_000_000
@@ -324,4 +325,4 @@ pay = 10_000
 upper_threshold = 90
 lower_threshold = 50
 max_gas_price = 3
-min_gas_price = 1
+min_gas_price = 1

smart_contracts/contracts/client/burn/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "burn"
+version = "0.1.0"
+authors = ["Igor Bunar <[email protected]>", "Jan Hoffmann <[email protected]>"]
+edition = "2021"
+
+[[bin]]
+name = "burn"
+path = "src/main.rs"
+bench = false
+doctest = false
+test = false
+
+[dependencies]
+casper-contract = { path = "../../../contract" }
+casper-types = { path = "../../../../types" }