Implement ink! chain extensions

crates/env/Cargo.toml

@@ -60,4 +60,3 @@ std = [
     "sha3",
     "blake2",
 ]
-ink-unstable-chain-extensions = []

crates/env/src/api.rs

@@ -436,27 +436,6 @@ where
     })
 }
 
-/// Calls the chain extension with the given ID and inputs.
-///
-/// Returns the given output type.
-///
-/// # Errors
-///
-/// - If the given function ID does not exist in the runtime.
-/// - If the given inputs cannot be properly decoded by the runtime.
-/// - If the given output type cannot be properly decoded by the contract.
-/// - If some chain extension specific conditions are not met.
-#[cfg(feature = "ink-unstable-chain-extensions")]
-pub fn call_chain_extension<I, O>(func_id: u32, input: &I) -> Result<O>
-where
-    I: scale::Codec + 'static,
-    O: scale::Codec + 'static,
-{
-    <EnvInstance as OnInstance>::on_instance(|instance| {
-        EnvBackend::call_chain_extension(instance, func_id, input)
-    })
-}
-
 /// Returns the execution input to the executed contract and decodes it as `T`.
 ///
 /// # Note

crates/env/src/backend.rs

@@ -128,7 +128,7 @@ pub trait EnvBackend {
         H: CryptoHash,
         T: scale::Encode;
 
-    /// Calls the chain extension with the given ID and inputs.
+    /// Low-level interface to call a chain extension method.
     ///
     /// Returns the output of the chain extension of the specified type.
     ///
@@ -138,11 +138,29 @@ pub trait EnvBackend {
     /// - If the inputs had an unexpected encoding.
     /// - If the output could not be properly decoded.
     /// - If some extension specific condition has not been met.
-    #[cfg(feature = "ink-unstable-chain-extensions")]
-    fn call_chain_extension<I, O>(&mut self, func_id: u32, input: &I) -> Result<O>
+    ///
+    /// # Dev. Note
+    ///
+    /// A valid implementation applies the `status_to_result` closure on
+    /// the status code returned by the actual call to the chain extension
+    /// method.
+    /// Only if the closure finds that the given status code indicates a
+    /// successful call to the chain extension method is the resulting
+    /// output buffer passed to the `decode_to_result` closure, in order to
+    /// drive the decoding and error management process from the outside.
+    fn call_chain_extension<I, T, E, ErrorCode, F, D>(
+        &mut self,
+        func_id: u32,
+        input: &I,
+        status_to_result: F,
+        decode_to_result: D,
+    ) -> ::core::result::Result<T, E>
     where
-        I: scale::Codec + 'static,
-        O: scale::Codec + 'static;
+        I: scale::Encode,
+        T: scale::Decode,
+        E: From<ErrorCode>,
+        F: FnOnce(u32) -> ::core::result::Result<(), ErrorCode>,
+        D: FnOnce(&[u8]) -> ::core::result::Result<T, E>;
 }
 
 /// Environmental contract functionality.

crates/env/src/call/call_builder.rs

@@ -206,7 +206,7 @@ where
     E: Environment,
 {
     CallBuilder {
-        env_types: Default::default(),
+        env: Default::default(),
         callee: Default::default(),
         gas_limit: Default::default(),
         transferred_value: Default::default(),
@@ -220,7 +220,7 @@ pub struct CallBuilder<E, Callee, GasLimit, TransferredValue, Args, RetType>
 where
     E: Environment,
 {
-    env_types: PhantomData<fn() -> E>,
+    env: PhantomData<fn() -> E>,
     /// The current parameters that have been built up so far.
     callee: Callee,
     gas_limit: GasLimit,
@@ -242,7 +242,7 @@ where
     ) -> CallBuilder<E, Set<E::AccountId>, GasLimit, TransferredValue, Args, RetType>
     {
         CallBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             callee: Set(callee),
             gas_limit: self.gas_limit,
             transferred_value: self.transferred_value,
@@ -264,7 +264,7 @@ where
         gas_limit: u64,
     ) -> CallBuilder<E, Callee, Set<u64>, TransferredValue, Args, RetType> {
         CallBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             callee: self.callee,
             gas_limit: Set(gas_limit),
             transferred_value: self.transferred_value,
@@ -286,7 +286,7 @@ where
         transferred_value: E::Balance,
     ) -> CallBuilder<E, Callee, GasLimit, Set<E::Balance>, Args, RetType> {
         CallBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             callee: self.callee,
             gas_limit: self.gas_limit,
             transferred_value: Set(transferred_value),
@@ -327,7 +327,7 @@ where
         R: IndicateReturnType,
     {
         CallBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             callee: self.callee,
             gas_limit: self.gas_limit,
             transferred_value: self.transferred_value,
@@ -362,7 +362,7 @@ where
         RetType,
     > {
         CallBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             callee: self.callee,
             gas_limit: self.gas_limit,
             transferred_value: self.transferred_value,

crates/env/src/call/create_builder.rs

@@ -113,7 +113,7 @@ pub struct CreateBuilder<E, CodeHash, GasLimit, Endowment, Args, R>
 where
     E: Environment,
 {
-    env_types: PhantomData<fn() -> E>,
+    env: PhantomData<fn() -> E>,
     code_hash: CodeHash,
     gas_limit: GasLimit,
     endowment: Endowment,
@@ -181,7 +181,7 @@ where
     R: FromAccountId<E>,
 {
     CreateBuilder {
-        env_types: Default::default(),
+        env: Default::default(),
         code_hash: Default::default(),
         gas_limit: Default::default(),
         endowment: Default::default(),
@@ -202,7 +202,7 @@ where
         code_hash: E::Hash,
     ) -> CreateBuilder<E, Set<E::Hash>, GasLimit, Endowment, Args, R> {
         CreateBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             code_hash: Set(code_hash),
             gas_limit: self.gas_limit,
             endowment: self.endowment,
@@ -224,7 +224,7 @@ where
         gas_limit: u64,
     ) -> CreateBuilder<E, CodeHash, Set<u64>, Endowment, Args, R> {
         CreateBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             code_hash: self.code_hash,
             gas_limit: Set(gas_limit),
             endowment: self.endowment,
@@ -246,7 +246,7 @@ where
         endowment: E::Balance,
     ) -> CreateBuilder<E, CodeHash, GasLimit, Set<E::Balance>, Args, R> {
         CreateBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             code_hash: self.code_hash,
             gas_limit: self.gas_limit,
             endowment: Set(endowment),
@@ -276,7 +276,7 @@ where
     ) -> CreateBuilder<E, CodeHash, GasLimit, Endowment, Set<ExecutionInput<Args>>, R>
     {
         CreateBuilder {
-            env_types: Default::default(),
+            env: Default::default(),
             code_hash: self.code_hash,
             gas_limit: self.gas_limit,
             endowment: self.endowment,