diff --git a/substrate/frame/contracts/src/chain_extension.rs b/substrate/frame/contracts/src/chain_extension.rs
index 57101668f794d658539f38e3fae94160bdc516ea..29f8ad44a56ac9fe4d13b08369bcaaf6de182116 100644
--- a/substrate/frame/contracts/src/chain_extension.rs
+++ b/substrate/frame/contracts/src/chain_extension.rs
@@ -84,7 +84,6 @@ pub use crate::{exec::Ext, Config};
pub use frame_system::Config as SysConfig;
pub use pallet_contracts_primitives::ReturnFlags;
pub use sp_core::crypto::UncheckedFrom;
-pub use state::Init as InitState;
/// Result that returns a [`DispatchError`] on error.
pub type Result<T> = sp_std::result::Result<T, DispatchError>;
@@ -198,7 +197,7 @@ pub enum RetVal {
///
/// It uses [typestate programming](https://docs.rust-embedded.org/book/static-guarantees/typestate-programming.html)
/// to enforce the correct usage of the parameters passed to the chain extension.
-pub struct Environment<'a, 'b, E: Ext, S: state::State> {
+pub struct Environment<'a, 'b, E: Ext, S: State> {
/// The actual data of this type.
inner: Inner<'a, 'b, E>,
/// `S` is only used in the type system but never as value.
@@ -206,7 +205,7 @@ pub struct Environment<'a, 'b, E: Ext, S: state::State> {
}
/// Functions that are available in every state of this type.
-impl<'a, 'b, E: Ext, S: state::State> Environment<'a, 'b, E, S>
+impl<'a, 'b, E: Ext, S: State> Environment<'a, 'b, E, S>
where
<E::T as SysConfig>::AccountId: UncheckedFrom<<E::T as SysConfig>::Hash> + AsRef<[u8]>,
{
@@ -264,7 +263,7 @@ where
///
/// Those are the functions that determine how the arguments to the chain extensions
/// should be consumed.
-impl<'a, 'b, E: Ext> Environment<'a, 'b, E, state::Init> {
+impl<'a, 'b, E: Ext> Environment<'a, 'b, E, InitState> {
/// Creates a new environment for consumption by a chain extension.
///
/// It is only available to this crate because only the wasm runtime module needs to
@@ -284,23 +283,23 @@ impl<'a, 'b, E: Ext> Environment<'a, 'b, E, state::Init> {
}
/// Use all arguments as integer values.
- pub fn only_in(self) -> Environment<'a, 'b, E, state::OnlyIn> {
+ pub fn only_in(self) -> Environment<'a, 'b, E, OnlyInState> {
Environment { inner: self.inner, phantom: PhantomData }
}
/// Use input arguments as integer and output arguments as pointer to a buffer.
- pub fn prim_in_buf_out(self) -> Environment<'a, 'b, E, state::PrimInBufOut> {
+ pub fn prim_in_buf_out(self) -> Environment<'a, 'b, E, PrimInBufOutState> {
Environment { inner: self.inner, phantom: PhantomData }
}
/// Use input and output arguments as pointers to a buffer.
- pub fn buf_in_buf_out(self) -> Environment<'a, 'b, E, state::BufInBufOut> {
+ pub fn buf_in_buf_out(self) -> Environment<'a, 'b, E, BufInBufOutState> {
Environment { inner: self.inner, phantom: PhantomData }
}
}
/// Functions to use the input arguments as integers.
-impl<'a, 'b, E: Ext, S: state::PrimIn> Environment<'a, 'b, E, S> {
+impl<'a, 'b, E: Ext, S: PrimIn> Environment<'a, 'b, E, S> {
/// The `input_ptr` argument.
pub fn val0(&self) -> u32 {
self.inner.input_ptr
@@ -313,7 +312,7 @@ impl<'a, 'b, E: Ext, S: state::PrimIn> Environment<'a, 'b, E, S> {
}
/// Functions to use the output arguments as integers.
-impl<'a, 'b, E: Ext, S: state::PrimOut> Environment<'a, 'b, E, S> {
+impl<'a, 'b, E: Ext, S: PrimOut> Environment<'a, 'b, E, S> {
/// The `output_ptr` argument.
pub fn val2(&self) -> u32 {
self.inner.output_ptr
@@ -326,7 +325,7 @@ impl<'a, 'b, E: Ext, S: state::PrimOut> Environment<'a, 'b, E, S> {
}
/// Functions to use the input arguments as pointer to a buffer.
-impl<'a, 'b, E: Ext, S: state::BufIn> Environment<'a, 'b, E, S>
+impl<'a, 'b, E: Ext, S: BufIn> Environment<'a, 'b, E, S>
where
<E::T as SysConfig>::AccountId: UncheckedFrom<<E::T as SysConfig>::Hash> + AsRef<[u8]>,
{
@@ -389,7 +388,7 @@ where
}
/// Functions to use the output arguments as pointer to a buffer.
-impl<'a, 'b, E: Ext, S: state::BufOut> Environment<'a, 'b, E, S>
+impl<'a, 'b, E: Ext, S: BufOut> Environment<'a, 'b, E, S>
where
<E::T as SysConfig>::AccountId: UncheckedFrom<<E::T as SysConfig>::Hash> + AsRef<[u8]>,
{
@@ -438,31 +437,54 @@ struct Inner<'a, 'b, E: Ext> {
output_len_ptr: u32,
}
-/// Private submodule with public types to prevent other modules from naming them.
-mod state {
- pub trait State {}
-
- pub trait PrimIn: State {}
- pub trait PrimOut: State {}
- pub trait BufIn: State {}
- pub trait BufOut: State {}
-
- /// The initial state of an [`Environment`](`super::Environment`).
- /// See [typestate programming](https://docs.rust-embedded.org/book/static-guarantees/typestate-programming.html).
- pub enum Init {}
- pub enum OnlyIn {}
- pub enum PrimInBufOut {}
- pub enum BufInBufOut {}
-
- impl State for Init {}
- impl State for OnlyIn {}
- impl State for PrimInBufOut {}
- impl State for BufInBufOut {}
-
- impl PrimIn for OnlyIn {}
- impl PrimOut for OnlyIn {}
- impl PrimIn for PrimInBufOut {}
- impl BufOut for PrimInBufOut {}
- impl BufIn for BufInBufOut {}
- impl BufOut for BufInBufOut {}
+/// Any state of an [`Environment`] implements this trait.
+/// See [typestate programming](https://docs.rust-embedded.org/book/static-guarantees/typestate-programming.html).
+pub trait State: sealed::Sealed {}
+
+/// A state that uses primitive inputs.
+pub trait PrimIn: State {}
+
+/// A state that uses primitive outputs.
+pub trait PrimOut: State {}
+
+/// A state that uses a buffer as input.
+pub trait BufIn: State {}
+
+/// A state that uses a buffer as output.
+pub trait BufOut: State {}
+
+/// The initial state of an [`Environment`].
+pub enum InitState {}
+
+/// A state that uses all arguments as primitive inputs.
+pub enum OnlyInState {}
+
+/// A state that uses two arguments as primitive inputs and the other two as buffer output.
+pub enum PrimInBufOutState {}
+
+/// Uses a buffer for input and a buffer for output.
+pub enum BufInBufOutState {}
+
+mod sealed {
+ use super::*;
+
+ /// Trait to prevent users from implementing `State` for anything else.
+ pub trait Sealed {}
+
+ impl Sealed for InitState {}
+ impl Sealed for OnlyInState {}
+ impl Sealed for PrimInBufOutState {}
+ impl Sealed for BufInBufOutState {}
+
+ impl State for InitState {}
+ impl State for OnlyInState {}
+ impl State for PrimInBufOutState {}
+ impl State for BufInBufOutState {}
+
+ impl PrimIn for OnlyInState {}
+ impl PrimOut for OnlyInState {}
+ impl PrimIn for PrimInBufOutState {}
+ impl BufOut for PrimInBufOutState {}
+ impl BufIn for BufInBufOutState {}
+ impl BufOut for BufInBufOutState {}
}