feat: move Slot type into it's own library

Cargo.toml

@@ -96,6 +96,7 @@ members = [
 
   "tools/devnet-utils",
   "tools/parse-wasm-client-type",
+  "tools/slot-calculator",
   "tools/tidy",
   "tools/move-bindgen",
   "lib/move-bindgen-derive",
@@ -176,6 +177,7 @@ members = [
   "lib/state-lens-light-client-types",
   "lib/create3",
   "lib/linea-types",
+  "lib/slotlib",
 ]
 
 [workspace.package]
@@ -264,6 +266,7 @@ movement-light-client-types = { path = "lib/movement-light-client-types", defaul
 cosmos-sdk-event = { path = "lib/cosmos-sdk-event", default-features = false }
 
 serde-utils      = { path = "lib/serde-utils", default-features = false }
+slotlib          = { path = "lib/slotlib", default-features = false }
 ssz              = { path = "lib/ssz", default-features = false }
 ssz-derive       = { path = "lib/ssz-derive", default-features = false }
 subset-of        = { path = "lib/subset-of", default-features = false }

lib/arbitrum-verifier/Cargo.toml

@@ -19,6 +19,7 @@ arbitrum-light-client-types = { workspace = true }
 evm-storage-verifier        = { workspace = true }
 rlp                         = { workspace = true }
 sha3                        = { workspace = true }
+slotlib                     = { workspace = true }
 thiserror                   = { workspace = true }
 unionlabs                   = { workspace = true }
 

lib/arbitrum-verifier/src/lib.rs

@@ -3,10 +3,8 @@ use core::fmt::Debug;
 use arbitrum_light_client_types::{ClientState, Header};
 use evm_storage_verifier::{verify_account_storage_root, verify_storage_proof};
 use sha3::{Digest, Keccak256};
-use unionlabs::{
-    ethereum::slot::{MappingKey, Slot},
-    primitives::{H256, U256},
-};
+use slotlib::{MappingKey, Slot};
+use unionlabs::primitives::{H256, U256};
 
 #[derive(thiserror::Error, Debug, PartialEq, Clone)]
 pub enum Error {

lib/linea-verifier/Cargo.toml

@@ -21,5 +21,6 @@ linea-light-client-types = { workspace = true }
 linea-types              = { workspace = true }
 linea-zktrie             = { workspace = true }
 rlp                      = { workspace = true }
+slotlib                  = { workspace = true }
 thiserror                = { workspace = true }
 unionlabs                = { workspace = true }

lib/linea-verifier/src/lib.rs

@@ -4,10 +4,8 @@ use evm_storage_verifier::{verify_account_storage_root, verify_storage_proof};
 use gnark_mimc::new_mimc_constants_bls12_377;
 use linea_light_client_types::{ClientState, Header};
 use linea_types::account::ZkAccount;
-use unionlabs::{
-    ethereum::slot::{MappingKey, Slot},
-    primitives::{H256, U256},
-};
+use slotlib::{MappingKey, Slot};
+use unionlabs::primitives::{H256, U256};
 
 #[derive(Debug, Clone, PartialEq, thiserror::Error)]
 pub enum Error {

lib/scroll-verifier/Cargo.toml

@@ -19,6 +19,7 @@ evm-storage-verifier      = { workspace = true }
 rlp                       = { workspace = true }
 scroll-codec              = { workspace = true }
 scroll-light-client-types = { workspace = true }
+slotlib                   = { workspace = true }
 thiserror                 = { workspace = true }
 unionlabs                 = { workspace = true }
 zktrie                    = { workspace = true }

lib/scroll-verifier/src/lib.rs

@@ -3,8 +3,8 @@ use core::fmt::Debug;
 use evm_storage_verifier::{verify_account_storage_root, verify_storage_proof};
 use scroll_codec::{hash_batch, HashBatchError};
 use scroll_light_client_types::{ClientState, Header};
+use slotlib::{MappingKey, Slot};
 use unionlabs::{
-    ethereum::slot::{MappingKey, Slot},
     primitives::{H160, H256, U256},
     scroll::account::Account,
 };

lib/slotlib/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+edition.workspace      = true
+license-file.workspace = true
+name                   = "slotlib"
+repository.workspace   = true
+version                = "0.1.0"
+
+[dependencies]
+hex-literal          = { workspace = true }
+sha2                 = { workspace = true }
+sha3                 = { workspace = true }
+unionlabs-primitives = { workspace = true }
+
+[lints]
+workspace = true

lib/slotlib/src/lib.rs

@@ -0,0 +1,3 @@
+pub mod slot;
+
+pub use crate::slot::{MappingKey, Slot};

lib/slotlib/src/slot.rs

@@ -0,0 +1,85 @@
+use sha2::Digest;
+use sha3::Keccak256;
+use unionlabs_primitives::{H256, U256};
+
+// Duplication of keccak256 function defined in /lib/unionlabs/ethereum.rs, otherwise it creates a dependency cycle.
+#[inline]
+#[must_use]
+pub fn keccak256(bytes: impl AsRef<[u8]>) -> H256 {
+    Keccak256::new().chain_update(bytes).finalize().into()
+}
+
+/// Solidity storage slot calculations. Note that this currently does not handle dynamic arrays with packed values; the index passed to [`Slot::Array`] will need to be calculated manually in this case.
+pub enum Slot<'a> {
+    /// (base slot, index)
+    Array(&'a Slot<'a>, U256),
+    /// (base slot, mapping key)
+    Mapping(&'a Slot<'a>, MappingKey<'a>),
+    Offset(U256),
+}
+
+impl Slot<'_> {
+    // https://docs.soliditylang.org/en/latest/internals/layout_in_storage.html#mappings-and-dynamic-arrays
+    #[inline]
+    #[must_use = "calculating the slot has no effect"]
+    // REVIEW: Make const? <https://crates.io/crates/keccak-const/0.2.0>
+    pub fn slot(&self) -> U256 {
+        match self {
+            // keccak256(p)
+            Slot::Array(p, idx) => {
+                U256::from_be_bytes(*keccak256(p.slot().to_be_bytes()).get()) + *idx
+            }
+            // keccak256(h(k) . p)
+            Slot::Mapping(p, k) => {
+                let mut hasher = Keccak256::new();
+                match &k {
+                    MappingKey::String(string) => hasher.update(string.as_bytes()),
+                    MappingKey::Uint256(k) => hasher.update(k.to_be_bytes()),
+                    MappingKey::Uint64(k) => hasher.update(U256::from(*k).to_be_bytes()),
+                    MappingKey::Bytes32(k) => hasher.update(k.get()),
+                };
+
+                U256::from_be_bytes(
+                    hasher
+                        .chain_update(p.slot().to_be_bytes())
+                        .finalize()
+                        .into(),
+                )
+            }
+            Slot::Offset(p) => *p,
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum MappingKey<'a> {
+    String(&'a str),
+    Uint256(U256),
+    Uint64(u64),
+    Bytes32(H256),
+}
+
+#[test]
+fn test() {
+    // Test contract uploaded here: https://sepolia.etherscan.io/address/0x6845dbaa9513d3d07737ea9f6e350011dcfeb9bd
+
+    // mapping(uint256 => mapping(uint256 => uint256)[])
+    let slot = Slot::Mapping(
+        &Slot::Array(
+            &Slot::Mapping(
+                &Slot::Offset(0u32.into()),
+                MappingKey::Uint256(123u32.into()),
+            ),
+            1u32.into(),
+        ),
+        MappingKey::Uint256(100u32.into()),
+    )
+    .slot();
+
+    assert_eq!(
+        <H256>::new(slot.to_be_bytes()),
+        <H256>::new(hex_literal::hex!(
+            "00a9b48fe93e5d10ebc2d9021d1477088c6292bf047876944343f57fdf3f0467"
+        ))
+    );
+}

lib/unionlabs/Cargo.toml

@@ -53,6 +53,7 @@ near-primitives-core = { version = "0.21", optional = true }
 near-sdk             = { workspace = true, optional = true }
 schemars             = { workspace = true, features = ["derive"], optional = true }
 serde_bytes          = "0.11.6"
+slotlib              = { workspace = true }
 unionlabs-primitives = { workspace = true, features = ["generic-array-compat", "serde", "base64"] }
 
 [dev-dependencies]

lib/unionlabs/src/ethereum.rs

@@ -1,10 +1,8 @@
 use sha2::Digest;
 use sha3::Keccak256;
+use slotlib::{MappingKey, Slot};
 
-use crate::{
-    ethereum::slot::{MappingKey, Slot},
-    primitives::{H256, U256},
-};
+use crate::primitives::{H256, U256};
 
 pub mod slot;
 

tools/slot-calculator/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+edition      = { workspace = true }
+license-file = { workspace = true }
+name         = "slot-calculator"
+publish      = false
+repository   = { workspace = true }
+version      = "0.1.0"
+
+[lints]
+workspace = true
+
+[dependencies]
+clap        = { workspace = true, features = ["derive", "help"] }
+hex-literal = { workspace = true }
+sha2        = { workspace = true }
+sha3        = { workspace = true }
+slotlib     = { workspace = true }
+typed-arena = "2.0"
+unionlabs   = { workspace = true, features = ["rlp"] }