From 8a20d5cb52c07f241fe83932e1137b14ce3e343f Mon Sep 17 00:00:00 2001
From: Alex Beregszaszi <alex@rtfs.hu>
Date: Tue, 5 Nov 2019 11:56:03 +0000
Subject: [PATCH] rust: remove unneeded mutability in ExecutionContext

---
 CHANGELOG.md                     |  5 +++++
 bindings/rust/evmc-vm/src/lib.rs | 14 +++++++-------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 407bd7050..0b161700b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,11 @@ and this project adheres to [Semantic Versioning].
   which can be used to emulate Host behavior when testing VM implementations.
   [#456](https://github.com/ethereum/evmc/pull/456)
 
+### Changed
+
+- In the Rust bindings mark read-only EVMC functions as non-mutating.
+  [#444](https://github.com/ethereum/evmc/pull/444)
+
 
 ## [7.0.0] „Istanbul Ready” — 2019-11-11
 
diff --git a/bindings/rust/evmc-vm/src/lib.rs b/bindings/rust/evmc-vm/src/lib.rs
index 6f604e000..c0c1afb3f 100644
--- a/bindings/rust/evmc-vm/src/lib.rs
+++ b/bindings/rust/evmc-vm/src/lib.rs
@@ -214,7 +214,7 @@ impl<'a> ExecutionContext<'a> {
     }
 
     /// Check if an account exists.
-    pub fn account_exists(&mut self, address: &Address) -> bool {
+    pub fn account_exists(&self, address: &Address) -> bool {
         unsafe {
             assert!((*self.host).account_exists.is_some());
             (*self.host).account_exists.unwrap()(self.context, address as *const Address)
@@ -222,7 +222,7 @@ impl<'a> ExecutionContext<'a> {
     }
 
     /// Read from a storage key.
-    pub fn get_storage(&mut self, address: &Address, key: &Bytes32) -> Bytes32 {
+    pub fn get_storage(&self, address: &Address, key: &Bytes32) -> Bytes32 {
         unsafe {
             assert!((*self.host).get_storage.is_some());
             (*self.host).get_storage.unwrap()(
@@ -252,7 +252,7 @@ impl<'a> ExecutionContext<'a> {
     }
 
     /// Get balance of an account.
-    pub fn get_balance(&mut self, address: &Address) -> Uint256 {
+    pub fn get_balance(&self, address: &Address) -> Uint256 {
         unsafe {
             assert!((*self.host).get_balance.is_some());
             (*self.host).get_balance.unwrap()(self.context, address as *const Address)
@@ -260,7 +260,7 @@ impl<'a> ExecutionContext<'a> {
     }
 
     /// Get code size of an account.
-    pub fn get_code_size(&mut self, address: &Address) -> usize {
+    pub fn get_code_size(&self, address: &Address) -> usize {
         unsafe {
             assert!((*self.host).get_code_size.is_some());
             (*self.host).get_code_size.unwrap()(self.context, address as *const Address)
@@ -268,7 +268,7 @@ impl<'a> ExecutionContext<'a> {
     }
 
     /// Get code hash of an account.
-    pub fn get_code_hash(&mut self, address: &Address) -> Bytes32 {
+    pub fn get_code_hash(&self, address: &Address) -> Bytes32 {
         unsafe {
             assert!((*self.host).get_code_size.is_some());
             (*self.host).get_code_hash.unwrap()(self.context, address as *const Address)
@@ -276,7 +276,7 @@ impl<'a> ExecutionContext<'a> {
     }
 
     /// Copy code of an account.
-    pub fn copy_code(&mut self, address: &Address, code_offset: usize, buffer: &mut [u8]) -> usize {
+    pub fn copy_code(&self, address: &Address, code_offset: usize, buffer: &mut [u8]) -> usize {
         unsafe {
             assert!((*self.host).copy_code.is_some());
             (*self.host).copy_code.unwrap()(
@@ -338,7 +338,7 @@ impl<'a> ExecutionContext<'a> {
     }
 
     /// Get block hash of an account.
-    pub fn get_block_hash(&mut self, num: i64) -> Bytes32 {
+    pub fn get_block_hash(&self, num: i64) -> Bytes32 {
         unsafe {
             assert!((*self.host).get_block_hash.is_some());
             (*self.host).get_block_hash.unwrap()(self.context, num)