adds aliased types needed to describe EVM environment

chain-evm/src/machine.rs

@@ -9,7 +9,10 @@
 //! ## StackState<'config>
 //!
 
-use std::rc::Rc;
+use std::{
+    rc::Rc,
+    time::{SystemTime, UNIX_EPOCH},
+};
 
 use evm::{
     backend::{Apply, ApplyBackend, Backend, Basic, Log, MemoryVicinity},
@@ -23,14 +26,50 @@ use crate::state::AccountTrie;
 /// EVM Configuration.
 pub use evm::Config;
 
+/// A block's chain ID.
+pub type ChainId = U256;
+
+/// A block hash.
+pub type BlockHash = H256;
+
+/// A block hash.
+pub type BlockHashes = Vec<BlockHash>;
+
+/// A block's number.
+pub type BlockNumber = U256;
+
+/// A block's timestamp.
+pub struct BlockTimestamp;
+
+impl BlockTimestamp {
+    /// Returns the time since `UNIX_EPOCH` as `U256`
+    pub fn now() -> U256 {
+        U256::from(
+            SystemTime::now()
+                .duration_since(UNIX_EPOCH)
+                .unwrap()
+                .as_secs(),
+        )
+    }
+}
+
+/// A block's difficulty.
+pub type BlockDifficulty = U256;
+
+/// A block's gas limit.
+pub type BlockGasLimit = U256;
+
+/// A block's origin
+pub type Origin = H160;
+
 /// Gas quantity integer for EVM operations.
 pub type Gas = U256;
 
 /// Gas price integer for EVM operations.
 pub type GasPrice = U256;
 
 /// Gas limit for EVM operations.
-pub type GasLimit = u64;
+pub type GasLimit = U256;
 
 /// Integer of the value sent with an EVM transaction.
 pub type Value = U256;