From 838dbcbe91695980a6a2defbf59346d1d9764d65 Mon Sep 17 00:00:00 2001
From: Gavin Wood <gavin@parity.io>
Date: Wed, 1 Jun 2022 17:27:47 +0100
Subject: [PATCH] Helper macro for `Morph` impls (#11570)
* Helper macro for Morph impls
* No need to deprecate for now
* Improved macro
* Doc tests
* Grumbles
---
.../frame/ranked-collective/src/tests.rs | 4 +-
substrate/frame/support/src/traits.rs | 2 +-
.../frame/support/src/traits/dispatch.rs | 24 --
substrate/frame/support/src/traits/misc.rs | 72 +---
substrate/primitives/runtime/src/traits.rs | 369 +++++++++++++++++-
5 files changed, 376 insertions(+), 95 deletions(-)
diff --git a/substrate/frame/ranked-collective/src/tests.rs b/substrate/frame/ranked-collective/src/tests.rs
index 1426012b63c..4344a1be730 100644
--- a/substrate/frame/ranked-collective/src/tests.rs
+++ b/substrate/frame/ranked-collective/src/tests.rs
@@ -23,12 +23,12 @@ use frame_support::{
assert_noop, assert_ok,
error::BadOrigin,
parameter_types,
- traits::{ConstU16, ConstU32, ConstU64, EitherOf, Everything, MapSuccess, Polling, ReduceBy},
+ traits::{ConstU16, ConstU32, ConstU64, EitherOf, Everything, MapSuccess, Polling},
};
use sp_core::H256;
use sp_runtime::{
testing::Header,
- traits::{BlakeTwo256, Identity, IdentityLookup},
+ traits::{BlakeTwo256, Identity, IdentityLookup, ReduceBy},
};
use super::*;
diff --git a/substrate/frame/support/src/traits.rs b/substrate/frame/support/src/traits.rs
index fe983f5c292..53bdd219aa3 100644
--- a/substrate/frame/support/src/traits.rs
+++ b/substrate/frame/support/src/traits.rs
@@ -97,7 +97,7 @@ mod dispatch;
pub use dispatch::EnsureOneOf;
pub use dispatch::{
AsEnsureOriginWithArg, DispatchableWithStorageLayer, EitherOf, EitherOfDiverse, EnsureOrigin,
- EnsureOriginWithArg, MapSuccess, NeverEnsureOrigin, OriginTrait, ReduceBy, TryMapSuccess,
+ EnsureOriginWithArg, MapSuccess, NeverEnsureOrigin, OriginTrait, TryMapSuccess,
UnfilteredDispatchable,
};
diff --git a/substrate/frame/support/src/traits/dispatch.rs b/substrate/frame/support/src/traits/dispatch.rs
index 720baf6c8a4..9bfb0145009 100644
--- a/substrate/frame/support/src/traits/dispatch.rs
+++ b/substrate/frame/support/src/traits/dispatch.rs
@@ -18,15 +18,12 @@
//! Traits for dealing with dispatching calls and the origin from which they are dispatched.
use crate::dispatch::{DispatchResultWithPostInfo, Parameter, RawOrigin};
-use sp_arithmetic::traits::{CheckedSub, Zero};
use sp_runtime::{
traits::{BadOrigin, Member, Morph, TryMorph},
Either,
};
use sp_std::marker::PhantomData;
-use super::TypedGet;
-
/// Some sort of check on the origin is performed by this object.
pub trait EnsureOrigin<OuterOrigin> {
/// A return type.
@@ -226,27 +223,6 @@ impl<
}
}
-/// Mutator which reduces a scalar by a particular amount.
-pub struct ReduceBy<N>(PhantomData<N>);
-impl<N: TypedGet> TryMorph<N::Type> for ReduceBy<N>
-where
- N::Type: CheckedSub,
-{
- type Outcome = N::Type;
- fn try_morph(r: N::Type) -> Result<N::Type, ()> {
- r.checked_sub(&N::get()).ok_or(())
- }
-}
-impl<N: TypedGet> Morph<N::Type> for ReduceBy<N>
-where
- N::Type: CheckedSub + Zero,
-{
- type Outcome = N::Type;
- fn morph(r: N::Type) -> N::Type {
- r.checked_sub(&N::get()).unwrap_or(Zero::zero())
- }
-}
-
/// Type that can be dispatched with an origin but without checking the origin filter.
///
/// Implemented for pallet dispatchable type by `decl_module` and for runtime dispatchable by
diff --git a/substrate/frame/support/src/traits/misc.rs b/substrate/frame/support/src/traits/misc.rs
index bea4e2a3944..ced6df8f971 100644
--- a/substrate/frame/support/src/traits/misc.rs
+++ b/substrate/frame/support/src/traits/misc.rs
@@ -21,6 +21,11 @@ use crate::dispatch::Parameter;
use codec::{CompactLen, Decode, DecodeAll, Encode, EncodeLike, Input, MaxEncodedLen};
use scale_info::{build::Fields, meta_type, Path, Type, TypeInfo, TypeParameter};
use sp_arithmetic::traits::{CheckedAdd, CheckedMul, CheckedSub, Saturating};
+#[doc(hidden)]
+pub use sp_runtime::traits::{
+ ConstBool, ConstI128, ConstI16, ConstI32, ConstI64, ConstI8, ConstU128, ConstU16, ConstU32,
+ ConstU64, ConstU8, Get, GetDefault, TypedGet,
+};
use sp_runtime::{traits::Block as BlockT, DispatchError};
use sp_std::{cmp::Ordering, prelude::*};
@@ -387,73 +392,6 @@ where
}
}
-/// A trait for querying a single value from a type defined in the trait.
-///
-/// It is not required that the value is constant.
-pub trait TypedGet {
- /// The type which is returned.
- type Type;
- /// Return the current value.
- fn get() -> Self::Type;
-}
-
-/// A trait for querying a single value from a type.
-///
-/// It is not required that the value is constant.
-pub trait Get<T> {
- /// Return the current value.
- fn get() -> T;
-}
-
-impl<T: Default> Get<T> for () {
- fn get() -> T {
- T::default()
- }
-}
-
-/// Implement Get by returning Default for any type that implements Default.
-pub struct GetDefault;
-impl<T: Default> Get<T> for GetDefault {
- fn get() -> T {
- T::default()
- }
-}
-
-macro_rules! impl_const_get {
- ($name:ident, $t:ty) => {
- #[derive($crate::RuntimeDebug)]
- pub struct $name<const T: $t>;
- impl<const T: $t> Get<$t> for $name<T> {
- fn get() -> $t {
- T
- }
- }
- impl<const T: $t> Get<Option<$t>> for $name<T> {
- fn get() -> Option<$t> {
- Some(T)
- }
- }
- impl<const T: $t> TypedGet for $name<T> {
- type Type = $t;
- fn get() -> $t {
- T
- }
- }
- };
-}
-
-impl_const_get!(ConstBool, bool);
-impl_const_get!(ConstU8, u8);
-impl_const_get!(ConstU16, u16);
-impl_const_get!(ConstU32, u32);
-impl_const_get!(ConstU64, u64);
-impl_const_get!(ConstU128, u128);
-impl_const_get!(ConstI8, i8);
-impl_const_get!(ConstI16, i16);
-impl_const_get!(ConstI32, i32);
-impl_const_get!(ConstI64, i64);
-impl_const_get!(ConstI128, i128);
-
/// A type for which some values make sense to be able to drop without further consideration.
pub trait TryDrop: Sized {
/// Drop an instance cleanly. Only works if its value represents "no-operation".
diff --git a/substrate/primitives/runtime/src/traits.rs b/substrate/primitives/runtime/src/traits.rs
index ee6a526e95e..aa5908526b8 100644
--- a/substrate/primitives/runtime/src/traits.rs
+++ b/substrate/primitives/runtime/src/traits.rs
@@ -37,7 +37,9 @@ pub use sp_arithmetic::traits::{
UniqueSaturatedFrom, UniqueSaturatedInto, Zero,
};
use sp_core::{self, storage::StateVersion, Hasher, RuntimeDebug, TypeId};
-use sp_std::{self, fmt::Debug, marker::PhantomData, prelude::*};
+#[doc(hidden)]
+pub use sp_std::marker::PhantomData;
+use sp_std::{self, fmt::Debug, prelude::*};
#[cfg(feature = "std")]
use std::fmt::Display;
#[cfg(feature = "std")]
@@ -274,6 +276,192 @@ where
}
}
+/// A trait for querying a single value from a type defined in the trait.
+///
+/// It is not required that the value is constant.
+pub trait TypedGet {
+ /// The type which is returned.
+ type Type;
+ /// Return the current value.
+ fn get() -> Self::Type;
+}
+
+/// A trait for querying a single value from a type.
+///
+/// It is not required that the value is constant.
+pub trait Get<T> {
+ /// Return the current value.
+ fn get() -> T;
+}
+
+impl<T: Default> Get<T> for () {
+ fn get() -> T {
+ T::default()
+ }
+}
+
+/// Implement Get by returning Default for any type that implements Default.
+pub struct GetDefault;
+impl<T: Default> Get<T> for GetDefault {
+ fn get() -> T {
+ T::default()
+ }
+}
+
+macro_rules! impl_const_get {
+ ($name:ident, $t:ty) => {
+ #[doc = "Const getter for a basic type."]
+ #[derive($crate::RuntimeDebug)]
+ pub struct $name<const T: $t>;
+ impl<const T: $t> Get<$t> for $name<T> {
+ fn get() -> $t {
+ T
+ }
+ }
+ impl<const T: $t> Get<Option<$t>> for $name<T> {
+ fn get() -> Option<$t> {
+ Some(T)
+ }
+ }
+ impl<const T: $t> TypedGet for $name<T> {
+ type Type = $t;
+ fn get() -> $t {
+ T
+ }
+ }
+ };
+}
+
+impl_const_get!(ConstBool, bool);
+impl_const_get!(ConstU8, u8);
+impl_const_get!(ConstU16, u16);
+impl_const_get!(ConstU32, u32);
+impl_const_get!(ConstU64, u64);
+impl_const_get!(ConstU128, u128);
+impl_const_get!(ConstI8, i8);
+impl_const_get!(ConstI16, i16);
+impl_const_get!(ConstI32, i32);
+impl_const_get!(ConstI64, i64);
+impl_const_get!(ConstI128, i128);
+
+/// Create new implementations of the [`Get`](crate::traits::Get) trait.
+///
+/// The so-called parameter type can be created in four different ways:
+///
+/// - Using `const` to create a parameter type that provides a `const` getter. It is required that
+/// the `value` is const.
+///
+/// - Declare the parameter type without `const` to have more freedom when creating the value.
+///
+/// NOTE: A more substantial version of this macro is available in `frame_support` crate which
+/// allows mutable and persistant variants.
+///
+/// # Examples
+///
+/// ```
+/// # use sp_runtime::traits::Get;
+/// # use sp_runtime::parameter_types;
+/// // This function cannot be used in a const context.
+/// fn non_const_expression() -> u64 { 99 }
+///
+/// const FIXED_VALUE: u64 = 10;
+/// parameter_types! {
+/// pub const Argument: u64 = 42 + FIXED_VALUE;
+/// /// Visibility of the type is optional
+/// OtherArgument: u64 = non_const_expression();
+/// }
+///
+/// trait Config {
+/// type Parameter: Get<u64>;
+/// type OtherParameter: Get<u64>;
+/// }
+///
+/// struct Runtime;
+/// impl Config for Runtime {
+/// type Parameter = Argument;
+/// type OtherParameter = OtherArgument;
+/// }
+/// ```
+///
+/// # Invalid example:
+///
+/// ```compile_fail
+/// # use sp_runtime::traits::Get;
+/// # use sp_runtime::parameter_types;
+/// // This function cannot be used in a const context.
+/// fn non_const_expression() -> u64 { 99 }
+///
+/// parameter_types! {
+/// pub const Argument: u64 = non_const_expression();
+/// }
+/// ```
+#[macro_export]
+macro_rules! parameter_types {
+ (
+ $( #[ $attr:meta ] )*
+ $vis:vis const $name:ident: $type:ty = $value:expr;
+ $( $rest:tt )*
+ ) => (
+ $( #[ $attr ] )*
+ $vis struct $name;
+ $crate::parameter_types!(@IMPL_CONST $name , $type , $value);
+ $crate::parameter_types!( $( $rest )* );
+ );
+ (
+ $( #[ $attr:meta ] )*
+ $vis:vis $name:ident: $type:ty = $value:expr;
+ $( $rest:tt )*
+ ) => (
+ $( #[ $attr ] )*
+ $vis struct $name;
+ $crate::parameter_types!(@IMPL $name, $type, $value);
+ $crate::parameter_types!( $( $rest )* );
+ );
+ () => ();
+ (@IMPL_CONST $name:ident, $type:ty, $value:expr) => {
+ impl $name {
+ /// Returns the value of this parameter type.
+ pub const fn get() -> $type {
+ $value
+ }
+ }
+
+ impl<I: From<$type>> $crate::traits::Get<I> for $name {
+ fn get() -> I {
+ I::from(Self::get())
+ }
+ }
+
+ impl $crate::traits::TypedGet for $name {
+ type Type = $type;
+ fn get() -> $type {
+ Self::get()
+ }
+ }
+ };
+ (@IMPL $name:ident, $type:ty, $value:expr) => {
+ impl $name {
+ /// Returns the value of this parameter type.
+ pub fn get() -> $type {
+ $value
+ }
+ }
+
+ impl<I: From<$type>> $crate::traits::Get<I> for $name {
+ fn get() -> I {
+ I::from(Self::get())
+ }
+ }
+
+ impl $crate::traits::TypedGet for $name {
+ type Type = $type;
+ fn get() -> $type {
+ Self::get()
+ }
+ }
+ };
+}
+
/// Extensible conversion trait. Generic over only source type, with destination type being
/// associated.
pub trait Morph<A> {
@@ -310,6 +498,185 @@ impl<T> TryMorph<T> for Identity {
}
}
+/// Create a `Morph` and/or `TryMorph` impls with a simple closure-like expression.
+///
+/// # Examples
+///
+/// ```
+/// # use sp_runtime::{morph_types, traits::{Morph, TryMorph, TypedGet, ConstU32}};
+/// # use sp_arithmetic::traits::CheckedSub;
+///
+/// morph_types! {
+/// /// Replace by some other value; produce both `Morph` and `TryMorph` implementations
+/// pub type Replace<V: TypedGet> = |_| -> V::Type { V::get() };
+/// /// A private `Morph` implementation to reduce a `u32` by 10.
+/// type ReduceU32ByTen: Morph = |r: u32| -> u32 { r - 10 };
+/// /// A `TryMorph` implementation to reduce a scalar by a particular amount, checking for
+/// /// underflow.
+/// pub type CheckedReduceBy<N: TypedGet>: TryMorph = |r: N::Type| -> Result<N::Type, ()> {
+/// r.checked_sub(&N::get()).ok_or(())
+/// } where N::Type: CheckedSub;
+/// }
+///
+/// trait Config {
+/// type TestMorph1: Morph<u32>;
+/// type TestTryMorph1: TryMorph<u32>;
+/// type TestMorph2: Morph<u32>;
+/// type TestTryMorph2: TryMorph<u32>;
+/// }
+///
+/// struct Runtime;
+/// impl Config for Runtime {
+/// type TestMorph1 = Replace<ConstU32<42>>;
+/// type TestTryMorph1 = Replace<ConstU32<42>>;
+/// type TestMorph2 = ReduceU32ByTen;
+/// type TestTryMorph2 = CheckedReduceBy<ConstU32<10>>;
+/// }
+/// ```
+#[macro_export]
+macro_rules! morph_types {
+ (
+ @DECL $( #[doc = $doc:expr] )* $vq:vis $name:ident ()
+ ) => {
+ $( #[doc = $doc] )* $vq struct $name;
+ };
+ (
+ @DECL $( #[doc = $doc:expr] )* $vq:vis $name:ident ( $( $bound_id:ident ),+ )
+ ) => {
+ $( #[doc = $doc] )*
+ $vq struct $name < $($bound_id,)* > ( $crate::traits::PhantomData< ( $($bound_id,)* ) > ) ;
+ };
+ (
+ @IMPL $name:ty : ( $( $bounds:tt )* ) ( $( $where:tt )* )
+ = |$var:ident: $var_type:ty| -> $outcome:ty { $( $ex:expr )* }
+ ) => {
+ impl<$($bounds)*> $crate::traits::Morph<$var_type> for $name $( $where )? {
+ type Outcome = $outcome;
+ fn morph($var: $var_type) -> Self::Outcome { $( $ex )* }
+ }
+ };
+ (
+ @IMPL_TRY $name:ty : ( $( $bounds:tt )* ) ( $( $where:tt )* )
+ = |$var:ident: $var_type:ty| -> $outcome:ty { $( $ex:expr )* }
+ ) => {
+ impl<$($bounds)*> $crate::traits::TryMorph<$var_type> for $name $( $where )? {
+ type Outcome = $outcome;
+ fn try_morph($var: $var_type) -> Result<Self::Outcome, ()> { $( $ex )* }
+ }
+ };
+ (
+ @IMPL $name:ty : () ( $( $where:tt )* )
+ = |$var:ident: $var_type:ty| -> $outcome:ty { $( $ex:expr )* }
+ ) => {
+ impl $crate::traits::Morph<$var_type> for $name $( $where )? {
+ type Outcome = $outcome;
+ fn morph($var: $var_type) -> Self::Outcome { $( $ex )* }
+ }
+ };
+ (
+ @IMPL_TRY $name:ty : () ( $( $where:tt )* )
+ = |$var:ident: $var_type:ty| -> $outcome:ty { $( $ex:expr )* }
+ ) => {
+ impl $crate::traits::TryMorph<$var_type> for $name $( $where )? {
+ type Outcome = $outcome;
+ fn try_morph($var: $var_type) -> Result<Self::Outcome, ()> { $( $ex )* }
+ }
+ };
+ (
+ @IMPL_BOTH $name:ty : ( $( $bounds:tt )* ) ( $( $where:tt )* )
+ = |$var:ident: $var_type:ty| -> $outcome:ty { $( $ex:expr )* }
+ ) => {
+ morph_types! {
+ @IMPL $name : ($($bounds)*) ($($where)*)
+ = |$var: $var_type| -> $outcome { $( $ex )* }
+ }
+ morph_types! {
+ @IMPL_TRY $name : ($($bounds)*) ($($where)*)
+ = |$var: $var_type| -> $outcome { Ok({$( $ex )*}) }
+ }
+ };
+
+ (
+ $( #[doc = $doc:expr] )* $vq:vis type $name:ident
+ $( < $( $bound_id:ident $( : $bound_head:path $( | $bound_tail:path )* )? ),+ > )?
+ $(: $type:tt)?
+ = |_| -> $outcome:ty { $( $ex:expr )* };
+ $( $rest:tt )*
+ ) => {
+ morph_types! {
+ $( #[doc = $doc] )* $vq type $name
+ $( < $( $bound_id $( : $bound_head $( | $bound_tail )* )? ),+ > )?
+ EXTRA_GENERIC(X)
+ $(: $type)?
+ = |_x: X| -> $outcome { $( $ex )* };
+ $( $rest )*
+ }
+ };
+ (
+ $( #[doc = $doc:expr] )* $vq:vis type $name:ident
+ $( < $( $bound_id:ident $( : $bound_head:path $( | $bound_tail:path )* )? ),+ > )?
+ $( EXTRA_GENERIC ($extra:ident) )?
+ = |$var:ident: $var_type:ty| -> $outcome:ty { $( $ex:expr )* }
+ $( where $( $where_path:ty : $where_bound_head:path $( | $where_bound_tail:path )* ),* )?;
+ $( $rest:tt )*
+ ) => {
+ morph_types! { @DECL $( #[doc = $doc] )* $vq $name ( $( $( $bound_id ),+ )? ) }
+ morph_types! {
+ @IMPL_BOTH $name $( < $( $bound_id ),* > )? :
+ ( $( $( $bound_id $( : $bound_head $( + $bound_tail )* )? , )+ )? $( $extra )? )
+ ( $( where $( $where_path : $where_bound_head $( + $where_bound_tail )* ),* )? )
+ = |$var: $var_type| -> $outcome { $( $ex )* }
+ }
+ morph_types!{ $($rest)* }
+ };
+ (
+ $( #[doc = $doc:expr] )* $vq:vis type $name:ident
+ $( < $( $bound_id:ident $( : $bound_head:path $( | $bound_tail:path )* )? ),+ > )?
+ $( EXTRA_GENERIC ($extra:ident) )?
+ : Morph
+ = |$var:ident: $var_type:ty| -> $outcome:ty { $( $ex:expr )* }
+ $( where $( $where_path:ty : $where_bound_head:path $( | $where_bound_tail:path )* ),* )?;
+ $( $rest:tt )*
+ ) => {
+ morph_types! { @DECL $( #[doc = $doc] )* $vq $name ( $( $( $bound_id ),+ )? ) }
+ morph_types! {
+ @IMPL $name $( < $( $bound_id ),* > )? :
+ ( $( $( $bound_id $( : $bound_head $( + $bound_tail )* )? , )+ )? $( $extra )? )
+ ( $( where $( $where_path : $where_bound_head $( + $where_bound_tail )* ),* )? )
+ = |$var: $var_type| -> $outcome { $( $ex )* }
+ }
+ morph_types!{ $($rest)* }
+ };
+ (
+ $( #[doc = $doc:expr] )* $vq:vis type $name:ident
+ $( < $( $bound_id:ident $( : $bound_head:path $( | $bound_tail:path )* )? ),+ > )?
+ $( EXTRA_GENERIC ($extra:ident) )?
+ : TryMorph
+ = |$var:ident: $var_type:ty| -> Result<$outcome:ty, ()> { $( $ex:expr )* }
+ $( where $( $where_path:ty : $where_bound_head:path $( | $where_bound_tail:path )* ),* )?;
+ $( $rest:tt )*
+ ) => {
+ morph_types! { @DECL $( #[doc = $doc] )* $vq $name ( $( $( $bound_id ),+ )? ) }
+ morph_types! {
+ @IMPL_TRY $name $( < $( $bound_id ),* > )? :
+ ( $( $( $bound_id $( : $bound_head $( + $bound_tail )* )? , )+ )? $( $extra )? )
+ ( $( where $( $where_path : $where_bound_head $( + $where_bound_tail )* ),* )? )
+ = |$var: $var_type| -> $outcome { $( $ex )* }
+ }
+ morph_types!{ $($rest)* }
+ };
+ () => {}
+}
+
+morph_types! {
+ /// Morpher to disregard the source value and replace with another.
+ pub type Replace<V: TypedGet> = |_| -> V::Type { V::get() };
+ /// Mutator which reduces a scalar by a particular amount.
+ pub type ReduceBy<N: TypedGet> = |r: N::Type| -> N::Type {
+ r.checked_sub(&N::get()).unwrap_or(Zero::zero())
+ } where N::Type: CheckedSub | Zero;
+}
+
/// Extensible conversion trait. Generic over both source and destination types.
pub trait Convert<A, B> {
/// Make conversion.
--
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