udpated env to return the size of prev stored val

crates/engine/src/ext.rs

@@ -228,20 +228,18 @@ impl Engine {
     }
 
     /// Writes the encoded value into the storage at the given key.
-    pub fn set_storage(&mut self, key: &[u8; 32], encoded_value: &[u8]) {
+    /// Returns the size of the previously stored value at the key if any, or None.
+    pub fn set_storage(&mut self, key: &[u8; 32], encoded_value: &[u8]) -> Option<u32> {
         let callee = self.get_callee();
         let account_id = AccountId::from_bytes(&callee[..]);
 
         self.debug_info.inc_writes(account_id.clone());
         self.debug_info
             .record_cell_for_account(account_id, key.to_vec());
 
-        // We ignore if storage is already set for this key
-        let _ = self.database.insert_into_contract_storage(
-            &callee,
-            key,
-            encoded_value.to_vec(),
-        );
+        self.database
+            .insert_into_contract_storage(&callee, key, encoded_value.to_vec())
+            .map(|v| <u32>::try_from(v.len()).expect("usize to u32 conversion failed"))
     }
 
     /// Returns the decoded contract storage at the key if any.

crates/env/src/api.rs

@@ -184,7 +184,7 @@ where
 }
 
 /// Writes the value to the contract storage under the given key and returns
-/// the size of the pre-existing value at the specified key if any, or None.
+/// the size of pre-existing value at the specified key if any, or None.
 ///
 /// # Panics
 ///

crates/env/src/engine/off_chain/impls.rs

@@ -184,11 +184,12 @@ impl EnvInstance {
 }
 
 impl EnvBackend for EnvInstance {
-    fn set_contract_storage<V>(&mut self, _key: &Key, _value: &V) -> Option<u32>
+    fn set_contract_storage<V>(&mut self, key: &Key, value: &V) -> Option<u32>
     where
         V: scale::Encode,
     {
-        unimplemented!("the off-chain env does not implement `seal_set_storage`, yet")
+        let v = scale::Encode::encode(value);
+        self.engine.set_storage(key.as_ref(), &v[..])
     }
 
     fn get_contract_storage<R>(&mut self, key: &Key) -> Result<Option<R>>

crates/storage/src/lazy/mapping.rs

@@ -134,17 +134,6 @@ where
         push_packed_root(value, &self.storage_key(&key));
     }
 
-    /// Insert the given `value` to the contract storage.
-    /// Returns the size of the pre-existing value at the specified key if any, or None.
-    #[inline]
-    pub fn insert_checked<Q, R>(&mut self, key: Q, value: &R) -> Option<u32>
-    where
-        Q: scale::EncodeLike<K>,
-        R: scale::EncodeLike<V> + PackedLayout,
-    {
-        push_packed_root(value, &self.storage_key(&key))
-    }
-
     /// Get the `value` at `key` from the contract storage.
     ///
     /// Returns `None` if no `value` exists at the given `key`.