Rename palette -> frame (#41)

src/frame/contracts.rs

@@ -0,0 +1,95 @@
+//! Implements support for the pallet_contracts module.
+use crate::{
+    frame::{
+        Call,
+        balances::Balances,
+        system::System,
+    },
+};
+use parity_scale_codec::Encode;
+
+const MODULE: &str = "Contracts";
+const PUT_CODE: &str = "put_code";
+const CREATE: &str = "create";
+const CALL: &str = "call";
+
+/// Gas units are chosen to be represented by u64 so that gas metering
+/// instructions can operate on them efficiently.
+pub type Gas = u64;
+
+/// The subset of the `pallet_contracts::Trait` that a client must implement.
+pub trait Contracts: System + Balances {}
+
+/// Arguments for uploading contract code to the chain
+#[derive(Encode)]
+pub struct PutCodeArgs {
+    #[codec(compact)]
+    gas_limit: Gas,
+    code: Vec<u8>,
+}
+
+/// Arguments for creating an instance of a contract
+#[derive(Encode)]
+pub struct CreateArgs<T: Contracts> {
+    endowment: <T as Balances>::Balance,
+    #[codec(compact)]
+    gas_limit: Gas,
+    code_hash: <T as System>::Hash,
+    data: Vec<u8>,
+}
+
+/// Arguments for calling a contract
+#[derive(Encode)]
+pub struct CallArgs<T: Contracts> {
+    dest: <T as System>::Address,
+    value: <T as Balances>::Balance,
+    #[codec(compact)]
+    gas_limit: Gas,
+    data: Vec<u8>,
+}
+
+/// Stores the given binary Wasm code into the chain's storage and returns
+/// its `codehash`.
+/// You can instantiate contracts only with stored code.
+pub fn put_code(gas_limit: Gas, code: Vec<u8>) -> Call<PutCodeArgs> {
+    Call::new(MODULE, PUT_CODE, PutCodeArgs { gas_limit, code })
+}
+
+/// Creates a new contract from the `codehash` generated by `put_code`,
+/// optionally transferring some balance.
+///
+/// Creation is executed as follows:
+///
+/// - The destination address is computed based on the sender and hash of
+/// the code.
+/// - The smart-contract account is created at the computed address.
+/// - The `ctor_code` is executed in the context of the newly-created
+/// account. Buffer returned after the execution is saved as the `code`https://www.bbc.co.uk/
+/// of the account. That code will be invoked upon any call received by
+/// this account.
+/// - The contract is initialized.
+pub fn create<T: Contracts>(
+    endowment: <T as Balances>::Balance,
+    gas_limit: Gas,
+    code_hash: <T as System>::Hash,
+    data: Vec<u8>,
+) -> Call<CreateArgs<T>> {
+    Call::new(MODULE, CREATE, CreateArgs { endowment, gas_limit, code_hash, data })
+}
+
+/// Makes a call to an account, optionally transferring some balance.
+///
+/// * If the account is a smart-contract account, the associated code will
+///  be executed and any value will be transferred.
+/// * If the account is a regular account, any value will be transferred.
+/// * If no account exists and the call value is not less than
+/// `existential_deposit`, a regular account will be created and any value
+///  will be transferred.
+pub fn call<T: Contracts>(
+    dest: <T as System>::Address,
+    value: <T as Balances>::Balance,
+    gas_limit: Gas,
+    data: Vec<u8>,
+) -> Call<CallArgs<T>> {
+    Call::new(MODULE, CALL, CallArgs { dest, value, gas_limit, data })
+}