Support caller_is_root

crates/env/src/api.rs

@@ -729,6 +729,26 @@ where
     })
 }
 
+/// Checks whether the caller of the current contract is root.
+///
+/// Note that only the origin of the call stack can be root. Hence this function returning
+/// `true` implies that the contract is being called by the origin.
+///
+/// A return value of `true` indicates that this contract is being called by a root origin,
+/// and `false` indicates that the caller is a signed origin.
+///
+/// # Errors
+///
+/// If the returned value cannot be properly decoded.
+pub fn caller_is_root<E>() -> bool
+where
+    E: Environment,
+{
+    <EnvInstance as OnInstance>::on_instance(|instance| {
+        TypedEnvBackend::caller_is_root::<E>(instance)
+    })
+}
+
 /// Replace the contract code at the specified address with new code.
 ///
 /// # Note

crates/env/src/backend.rs

@@ -413,6 +413,15 @@ pub trait TypedEnvBackend: EnvBackend {
     where
         E: Environment;
 
+    /// Checks whether the caller of the current contract is root.
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`caller_is_root`][`crate::caller_is_root`]
+    fn caller_is_root<E>(&mut self) -> bool
+    where
+        E: Environment;
+
     /// Retrieves the code hash of the contract at the given `account` id.
     ///
     /// # Note

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

@@ -567,6 +567,13 @@ impl TypedEnvBackend for EnvInstance {
         unimplemented!("off-chain environment does not support cross-contract calls")
     }
 
+    fn caller_is_root<E>(&mut self) -> bool
+    where
+        E: Environment,
+    {
+        unimplemented!("off-chain environment does not support cross-contract calls")
+    }
+
     fn code_hash<E>(&mut self, _account: &E::AccountId) -> Result<E::Hash>
     where
         E: Environment,

crates/ink/src/env_access.rs

@@ -1178,6 +1178,37 @@ where
         ink_env::caller_is_origin::<E>()
     }
 
+    /// Checks whether the caller of the current contract is root.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # #[ink::contract]
+    /// # pub mod my_contract {
+    /// #     #[ink(storage)]
+    /// #     pub struct MyContract { }
+    /// #
+    /// #     impl MyContract {
+    /// #         #[ink(constructor)]
+    /// #         pub fn new() -> Self {
+    /// #             Self {}
+    /// #         }
+    /// #
+    /// #[ink(message)]
+    /// pub fn caller_is_root(&mut self) -> bool {
+    ///     self.env().caller_is_root()
+    /// }
+    /// #    }
+    /// # }
+    /// ```
+    ///
+    /// # Note
+    ///
+    /// For more details visit: [`ink_env::caller_is_root`]
+    pub fn caller_is_root(self) -> bool {
+        ink_env::caller_is_root::<E>()
+    }
+
     /// Returns the code hash of the contract at the given `account` id.
     ///
     /// # Example