diff --git a/substrate/frame/elections-phragmen/src/migrations_3_0_0.rs b/substrate/frame/elections-phragmen/src/migrations_3_0_0.rs
index 8adc4c1a69f7c41cef7303e04065253c5f69d5ab..8afc9ed66920b352bf8dbd99c686f3d6a45f0ffb 100644
--- a/substrate/frame/elections-phragmen/src/migrations_3_0_0.rs
+++ b/substrate/frame/elections-phragmen/src/migrations_3_0_0.rs
@@ -21,7 +21,6 @@ use codec::{Encode, Decode, FullCodec};
use sp_std::prelude::*;
use frame_support::{
RuntimeDebug, weights::Weight, Twox64Concat,
- storage::types::{StorageMap, StorageValue},
traits::{GetPalletVersion, PalletVersion},
};
@@ -51,38 +50,21 @@ pub trait V2ToV3 {
type Balance: 'static + FullCodec + Copy;
}
-struct __Candidates;
-impl frame_support::traits::StorageInstance for __Candidates {
- fn pallet_prefix() -> &'static str { "PhragmenElection" }
- const STORAGE_PREFIX: &'static str = "Candidates";
-}
-
-#[allow(type_alias_bounds)]
-type Candidates<T: V2ToV3> = StorageValue<__Candidates, Vec<(T::AccountId, T::Balance)>>;
-
-struct __Members;
-impl frame_support::traits::StorageInstance for __Members {
- fn pallet_prefix() -> &'static str { "PhragmenElection" }
- const STORAGE_PREFIX: &'static str = "Members";
-}
-#[allow(type_alias_bounds)]
-type Members<T: V2ToV3> = StorageValue<__Members, Vec<SeatHolder<T::AccountId, T::Balance>>>;
-
-struct __RunnersUp;
-impl frame_support::traits::StorageInstance for __RunnersUp {
- fn pallet_prefix() -> &'static str { "PhragmenElection" }
- const STORAGE_PREFIX: &'static str = "RunnersUp";
-}
-#[allow(type_alias_bounds)]
-type RunnersUp<T: V2ToV3> = StorageValue<__RunnersUp, Vec<SeatHolder<T::AccountId, T::Balance>>>;
-
-struct __Voting;
-impl frame_support::traits::StorageInstance for __Voting {
- fn pallet_prefix() -> &'static str { "PhragmenElection" }
- const STORAGE_PREFIX: &'static str = "Voting";
-}
-#[allow(type_alias_bounds)]
-type Voting<T: V2ToV3> = StorageMap<__Voting, Twox64Concat, T::AccountId, Voter<T::AccountId, T::Balance>>;
+frame_support::generate_storage_alias!(
+ PhragmenElection, Candidates<T: V2ToV3> => Value<Vec<(T::AccountId, T::Balance)>>
+);
+frame_support::generate_storage_alias!(
+ PhragmenElection, Members<T: V2ToV3> => Value<Vec<SeatHolder<T::AccountId, T::Balance>>>
+);
+frame_support::generate_storage_alias!(
+ PhragmenElection, RunnersUp<T: V2ToV3> => Value<Vec<SeatHolder<T::AccountId, T::Balance>>>
+);
+frame_support::generate_storage_alias!(
+ PhragmenElection, Voting<T: V2ToV3> => Map<
+ (Twox64Concat, T::AccountId),
+ Voter<T::AccountId, T::Balance>
+ >
+);
/// Apply all of the migrations from 2_0_0 to 3_0_0.
///
diff --git a/substrate/frame/staking/src/lib.rs b/substrate/frame/staking/src/lib.rs
index 0ec976e37712319563b808fe7fcaaf9555ccabf0..c28dbc87bccddd0597327e8e90c9c3e048f5f174 100644
--- a/substrate/frame/staking/src/lib.rs
+++ b/substrate/frame/staking/src/lib.rs
@@ -1036,30 +1036,15 @@ pub mod migrations {
pub mod v6 {
use super::*;
- use frame_support::{traits::Get, weights::Weight, pallet_prelude::*};
-
- macro_rules! generate_storage_types {
- ($name:ident => Value<$value:ty>) => {
- paste::paste! {
- struct [<$name Instance>];
- impl frame_support::traits::StorageInstance for [<$name Instance>] {
- fn pallet_prefix() -> &'static str {
- "Staking"
- }
- const STORAGE_PREFIX: &'static str = stringify!($name);
- }
- type $name = StorageValue<[<$name Instance>], $value, ValueQuery>;
- }
- }
- }
+ use frame_support::{traits::Get, weights::Weight, generate_storage_alias};
// NOTE: value type doesn't matter, we just set it to () here.
- generate_storage_types!(SnapshotValidators => Value<()>);
- generate_storage_types!(SnapshotNominators => Value<()>);
- generate_storage_types!(QueuedElected => Value<()>);
- generate_storage_types!(QueuedScore => Value<()>);
- generate_storage_types!(EraElectionStatus => Value<()>);
- generate_storage_types!(IsCurrentSessionFinal => Value<()>);
+ generate_storage_alias!(Staking, SnapshotValidators => Value<()>);
+ generate_storage_alias!(Staking, SnapshotNominators => Value<()>);
+ generate_storage_alias!(Staking, QueuedElected => Value<()>);
+ generate_storage_alias!(Staking, QueuedScore => Value<()>);
+ generate_storage_alias!(Staking, EraElectionStatus => Value<()>);
+ generate_storage_alias!(Staking, IsCurrentSessionFinal => Value<()>);
/// check to execute prior to migration.
pub fn pre_migrate<T: Config>() -> Result<(), &'static str> {
diff --git a/substrate/frame/support/src/lib.rs b/substrate/frame/support/src/lib.rs
index 220e7a06bdf3146cd1c4eb24b1889c9c8966c310..362c4c5a0a73bd267a856af0ac93f92caeeef008 100644
--- a/substrate/frame/support/src/lib.rs
+++ b/substrate/frame/support/src/lib.rs
@@ -87,6 +87,124 @@ pub const LOG_TARGET: &'static str = "runtime::frame-support";
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum Never {}
+/// Generate a new type alias for [`storage::types::value::StorageValue`],
+/// [`storage::types::value::StorageMap`] and [`storage::types::value::StorageDoubleMap`].
+///
+/// Useful for creating a *storage-like* struct for test and migrations.
+///
+///```
+/// # use frame_support::generate_storage_alias;
+/// use frame_support::codec;
+/// use frame_support::Twox64Concat;
+/// // generate a storage value with type u32.
+/// generate_storage_alias!(Prefix, StorageName => Value<u32>);
+///
+/// // generate a double map from `(u32, u32)` (with hasher `Twox64Concat`) to `Vec<u8>`
+/// generate_storage_alias!(
+/// OtherPrefix, OtherStorageName => DoubleMap<
+/// (u32, u32),
+/// (u32, u32),
+/// Vec<u8>
+/// >
+/// );
+///
+/// // generate a map from `Config::AccountId` (with hasher `Twox64Concat`) to `Vec<u8>`
+/// trait Config { type AccountId: codec::FullCodec; }
+/// generate_storage_alias!(
+/// Prefix, GenericStorage<T: Config> => Map<(Twox64Concat, T::AccountId), Vec<u8>>
+/// );
+/// # fn main() {}
+///```
+#[macro_export]
+macro_rules! generate_storage_alias {
+ // without generic for $name.
+ ($pallet:ident, $name:ident => Map<($key:ty, $hasher:ty), $value:ty>) => {
+ $crate::paste::paste! {
+ $crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+ type $name = $crate::storage::types::StorageMap<
+ [<$name Instance>],
+ $hasher,
+ $key,
+ $value,
+ >;
+ }
+ };
+ ($pallet:ident, $name:ident => DoubleMap<($key1:ty, $hasher1:ty), ($key2:ty, $hasher2:ty), $value:ty>) => {
+ $crate::paste::paste! {
+ $crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+ type $name = $crate::storage::types::StorageMap<
+ [<$name Instance>],
+ $hasher1,
+ $key1,
+ $hasher2,
+ $key2,
+ $value,
+ >;
+ }
+ };
+ ($pallet:ident, $name:ident => Value<$value:ty>) => {
+ $crate::paste::paste! {
+ $crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+ type $name = $crate::storage::types::StorageValue<
+ [<$name Instance>],
+ $value,
+ >;
+ }
+ };
+ // with generic for $name.
+ ($pallet:ident, $name:ident<$t:ident : $bounds:tt> => Map<($key:ty, $hasher:ty), $value:ty>) => {
+ $crate::paste::paste! {
+ $crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+ #[allow(type_alias_bounds)]
+ type $name<$t : $bounds> = $crate::storage::types::StorageMap<
+ [<$name Instance>],
+ $key,
+ $hasher,
+ $value,
+ >;
+ }
+ };
+ (
+ $pallet:ident,
+ $name:ident<$t:ident : $bounds:tt>
+ => DoubleMap<($key1:ty, $hasher1:ty), ($key2:ty, $hasher2:ty), $value:ty>)
+ => {
+ $crate::paste::paste! {
+ $crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+ #[allow(type_alias_bounds)]
+ type $name<$t : $bounds> = $crate::storage::types::StorageMap<
+ [<$name Instance>],
+ $key1,
+ $hasher1,
+ $key2,
+ $hasher2,
+ $value,
+ >;
+ }
+ };
+ ($pallet:ident, $name:ident<$t:ident : $bounds:tt> => Value<$value:ty>) => {
+ $crate::paste::paste! {
+ $crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+ #[allow(type_alias_bounds)]
+ type $name<$t : $bounds> = $crate::storage::types::StorageValue<
+ [<$name Instance>],
+ $value,
+ $crate::storage::types::ValueQuery,
+ >;
+ }
+ };
+ // helper used in all arms.
+ (@GENERATE_INSTANCE_STRUCT $pallet:ident, $name:ident) => {
+ $crate::paste::paste! {
+ struct [<$name Instance>];
+ impl $crate::traits::StorageInstance for [<$name Instance>] {
+ fn pallet_prefix() -> &'static str { stringify!($pallet) }
+ const STORAGE_PREFIX: &'static str = stringify!($name);
+ }
+ }
+ }
+}
+
/// Create new implementations of the [`Get`](crate::traits::Get) trait.
///
/// The so-called parameter type can be created in four different ways: