Newer
Older
assert_eq!(
Map::iter().collect::<Vec<_>>().sorted(),
vec![(key - 2, 42), (key - 1, 43), (key, 15)]
);
Map::mutate(&key, |val| {
*val = 17;
});
assert_eq!(
Map::iter().collect::<Vec<_>>().sorted(),
vec![(key - 2, 42), (key - 1, 43), (key, 17)]
);
// remove first
Map::remove(&key);
assert_eq!(
Map::iter().collect::<Vec<_>>().sorted(),
vec![(key - 2, 42), (key - 1, 43)]
);
// remove last from the list
Map::remove(&(key - 2));
assert_eq!(Map::iter().collect::<Vec<_>>().sorted(), vec![(key - 1, 43)]);
// remove the last element
Map::remove(&(key - 1));
assert_eq!(Map::iter().collect::<Vec<_>>().sorted(), vec![]);
#[test]
fn double_map_basic_insert_remove_remove_prefix_should_work() {
new_test_ext().execute_with(|| {
type DoubleMap = DataDM;
assert_eq!(DoubleMap::get(&15u32, &16u32), 42u64);
// get / insert / take
let key1 = 17u32;
let key2 = 18u32;
assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
DoubleMap::insert(&key1, &key2, &4u64);
assert_eq!(DoubleMap::get(&key1, &key2), 4u64);
assert_eq!(DoubleMap::take(&key1, &key2), 4u64);
assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
DoubleMap::mutate(&key1, &key2, |val| {
assert_eq!(DoubleMap::get(&key1, &key2), 15u64);
DoubleMap::remove(&key1, &key2);
assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
DoubleMap::insert(&key1, &key2, &4u64);
DoubleMap::insert(&key1, &(key2 + 1), &4u64);
DoubleMap::insert(&(key1 + 1), &key2, &4u64);
DoubleMap::insert(&(key1 + 1), &(key2 + 1), &4u64);
assert!(matches!(
DoubleMap::remove_prefix(&key1, None),
sp_io::KillStorageResult::AllRemoved(0), // all in overlay
));
assert_eq!(DoubleMap::get(&key1, &key2), 0u64);
assert_eq!(DoubleMap::get(&key1, &(key2 + 1)), 0u64);
assert_eq!(DoubleMap::get(&(key1 + 1), &key2), 4u64);
assert_eq!(DoubleMap::get(&(key1 + 1), &(key2 + 1)), 4u64);
});
}
#[test]
fn double_map_append_should_work() {
new_test_ext().execute_with(|| {
type DoubleMap = AppendableDM<Test>;
let key1 = 17u32;
let key2 = 18u32;
DoubleMap::insert(&key1, &key2, &vec![1]);
DoubleMap::append(&key1, &key2, 2);
assert_eq!(DoubleMap::get(&key1, &key2), &[1, 2]);
#[test]
fn double_map_mutate_exists_should_work() {
new_test_ext().execute_with(|| {
type DoubleMap = DataDM;
let (key1, key2) = (11, 13);
// mutated
DoubleMap::mutate_exists(key1, key2, |v| *v = Some(1));
assert_eq!(DoubleMap::get(&key1, key2), 1);
// removed if mutated to `None`
DoubleMap::mutate_exists(key1, key2, |v| *v = None);
assert!(!DoubleMap::contains_key(&key1, key2));
});
}
#[test]
fn double_map_try_mutate_exists_should_work() {
new_test_ext().execute_with(|| {
type DoubleMap = DataDM;
type TestResult = result::Result<(), &'static str>;
let (key1, key2) = (11, 13);
// mutated if `Ok`
assert_ok!(DoubleMap::try_mutate_exists(key1, key2, |v| -> TestResult {
*v = Some(1);
Ok(())
}));
assert_eq!(DoubleMap::get(&key1, key2), 1);
// no-op if `Err`
assert_noop!(
DoubleMap::try_mutate_exists(key1, key2, |v| -> TestResult {
*v = Some(2);
Err("nah")
}),
"nah"
);
// removed if mutated to`None`
assert_ok!(DoubleMap::try_mutate_exists(key1, key2, |v| -> TestResult {
*v = None;
Ok(())
}));
assert!(!DoubleMap::contains_key(&key1, key2));
});
const EXPECTED_METADATA: StorageMetadata = StorageMetadata {
prefix: DecodeDifferent::Encode("Test"),
entries: DecodeDifferent::Encode(&[
StorageEntryMetadata {
name: DecodeDifferent::Encode("Data"),
modifier: StorageEntryModifier::Default,
ty: StorageEntryType::Map {
hasher: StorageHasher::Twox64Concat,
key: DecodeDifferent::Encode("u32"),
value: DecodeDifferent::Encode("u64"),
unused: false,
default: DecodeDifferent::Encode(DefaultByteGetter(&__GetByteStructData(
PhantomData::<Test>,
))),
documentation: DecodeDifferent::Encode(&[]),
},
StorageEntryMetadata {
name: DecodeDifferent::Encode("OptionLinkedMap"),
modifier: StorageEntryModifier::Optional,
ty: StorageEntryType::Map {
hasher: StorageHasher::Blake2_128Concat,
key: DecodeDifferent::Encode("u32"),
value: DecodeDifferent::Encode("u32"),
unused: false,
default: DecodeDifferent::Encode(DefaultByteGetter(
&__GetByteStructOptionLinkedMap(PhantomData::<Test>),
)),
documentation: DecodeDifferent::Encode(&[]),
},
StorageEntryMetadata {
name: DecodeDifferent::Encode("GenericData"),
modifier: StorageEntryModifier::Default,
ty: StorageEntryType::Map {
hasher: StorageHasher::Identity,
key: DecodeDifferent::Encode("T::BlockNumber"),
value: DecodeDifferent::Encode("T::BlockNumber"),
unused: false,
default: DecodeDifferent::Encode(DefaultByteGetter(&__GetByteStructGenericData(
PhantomData::<Test>,
))),
documentation: DecodeDifferent::Encode(&[]),
},
StorageEntryMetadata {
name: DecodeDifferent::Encode("GenericData2"),
modifier: StorageEntryModifier::Optional,
ty: StorageEntryType::Map {
hasher: StorageHasher::Blake2_128Concat,
key: DecodeDifferent::Encode("T::BlockNumber"),
value: DecodeDifferent::Encode("T::BlockNumber"),
unused: false,
default: DecodeDifferent::Encode(DefaultByteGetter(&__GetByteStructGenericData2(
PhantomData::<Test>,
))),
documentation: DecodeDifferent::Encode(&[]),
},
StorageEntryMetadata {
name: DecodeDifferent::Encode("DataDM"),
modifier: StorageEntryModifier::Default,
ty: StorageEntryType::DoubleMap {
hasher: StorageHasher::Twox64Concat,
key1: DecodeDifferent::Encode("u32"),
key2: DecodeDifferent::Encode("u32"),
value: DecodeDifferent::Encode("u64"),
key2_hasher: StorageHasher::Blake2_128Concat,
default: DecodeDifferent::Encode(DefaultByteGetter(&__GetByteStructDataDM(
PhantomData::<Test>,
))),
documentation: DecodeDifferent::Encode(&[]),
},
StorageEntryMetadata {
name: DecodeDifferent::Encode("GenericDataDM"),
modifier: StorageEntryModifier::Default,
ty: StorageEntryType::DoubleMap {
hasher: StorageHasher::Blake2_128Concat,
key1: DecodeDifferent::Encode("T::BlockNumber"),
key2: DecodeDifferent::Encode("T::BlockNumber"),
value: DecodeDifferent::Encode("T::BlockNumber"),
key2_hasher: StorageHasher::Identity,
default: DecodeDifferent::Encode(DefaultByteGetter(&__GetByteStructGenericDataDM(
PhantomData::<Test>,
))),
documentation: DecodeDifferent::Encode(&[]),
},
StorageEntryMetadata {
name: DecodeDifferent::Encode("GenericData2DM"),
modifier: StorageEntryModifier::Optional,
ty: StorageEntryType::DoubleMap {
hasher: StorageHasher::Blake2_128Concat,
key1: DecodeDifferent::Encode("T::BlockNumber"),
key2: DecodeDifferent::Encode("T::BlockNumber"),
value: DecodeDifferent::Encode("T::BlockNumber"),
key2_hasher: StorageHasher::Twox64Concat,
default: DecodeDifferent::Encode(DefaultByteGetter(
&__GetByteStructGenericData2DM(PhantomData::<Test>),
)),
documentation: DecodeDifferent::Encode(&[]),
},
StorageEntryMetadata {
name: DecodeDifferent::Encode("AppendableDM"),
modifier: StorageEntryModifier::Default,
ty: StorageEntryType::DoubleMap {
hasher: StorageHasher::Blake2_128Concat,
key1: DecodeDifferent::Encode("u32"),
key2: DecodeDifferent::Encode("T::BlockNumber"),
value: DecodeDifferent::Encode("Vec<u32>"),
key2_hasher: StorageHasher::Blake2_128Concat,
default: DecodeDifferent::Encode(DefaultByteGetter(
&__GetByteStructGenericData2DM(PhantomData::<Test>),
)),
documentation: DecodeDifferent::Encode(&[]),
},
]),
#[test]
fn store_metadata() {
let metadata = Module::<Test>::storage_metadata();
pretty_assertions::assert_eq!(EXPECTED_METADATA, metadata);
parameter_types! {
storage StorageParameter: u64 = 10;
}
#[test]
fn check_storage_parameter_type_works() {
TestExternalities::default().execute_with(|| {
assert_eq!(sp_io::hashing::twox_128(b":StorageParameter:"), StorageParameter::key());
assert_eq!(10, StorageParameter::get());
StorageParameter::set(&300);
assert_eq!(300, StorageParameter::get());
})
}
parameter_types! {
pub const BlockHashCount: u64 = 250;
pub static Members: Vec<u64> = vec![];
pub const Foo: Option<u64> = None;
}
/// Prelude to be used alongside pallet macro, for ease of use.
pub mod pallet_prelude {
#[cfg(feature = "std")]
pub use crate::traits::GenesisBuild;
pub use crate::{
dispatch::{DispatchError, DispatchResult, DispatchResultWithPostInfo, Parameter},
ensure,
inherent::{InherentData, InherentIdentifier, ProvideInherent},
storage,
storage::{
bounded_vec::BoundedVec,
types::{
Key as NMapKey, OptionQuery, StorageDoubleMap, StorageMap, StorageNMap,
StorageValue, ValueQuery,
},
},
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
traits::{
ConstU32, EnsureOrigin, Get, GetDefault, GetPalletVersion, Hooks, IsType,
PalletInfoAccess, StorageInfoTrait,
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
},
weights::{DispatchClass, Pays, Weight},
Blake2_128, Blake2_128Concat, Blake2_256, CloneNoBound, DebugNoBound, EqNoBound, Identity,
PartialEqNoBound, RuntimeDebug, RuntimeDebugNoBound, Twox128, Twox256, Twox64Concat,
pub use codec::{Decode, Encode, MaxEncodedLen};
pub use sp_runtime::{
traits::{MaybeSerializeDeserialize, Member, ValidateUnsigned},
transaction_validity::{
InvalidTransaction, TransactionLongevity, TransactionPriority, TransactionSource,
TransactionTag, TransactionValidity, TransactionValidityError, UnknownTransaction,
ValidTransaction,
pub use sp_std::marker::PhantomData;
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
}
/// `pallet` attribute macro allows to define a pallet to be used in `construct_runtime!`.
///
/// It is define by a module item:
/// ```ignore
/// #[pallet]
/// pub mod pallet {
/// ...
/// }
/// ```
///
/// Inside the module the macro will parse item with the attribute: `#[pallet::*]`, some attributes
/// are mandatory, some other optional.
///
/// The attribute are explained with the syntax of non instantiable pallets, to see how pallet with
/// instance work see below example.
///
/// Note various type can be automatically imported using pallet_prelude in frame_support and
/// frame_system:
/// ```ignore
/// #[pallet]
/// pub mod pallet {
/// use frame_support::pallet_prelude::*;
/// use frame_system::pallet_prelude::*;
/// ...
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
/// }
/// ```
///
/// # Config trait: `#[pallet::config]` mandatory
///
/// The trait defining generics of the pallet.
///
/// Item must be defined as
/// ```ignore
/// #[pallet::config]
/// pub trait Config: frame_system::Config + $optionally_some_other_supertraits
/// $optional_where_clause
/// {
/// ...
/// }
/// ```
/// I.e. a regular trait definition named `Config`, with supertrait `frame_system::Config`,
/// optionally other supertrait and where clause.
///
/// The associated type `Event` is reserved, if defined it must bounds `From<Event>` and
/// `IsType<<Self as frame_system::Config>::Event>`, see `#[pallet::event]` for more information.
///
/// To put `Get` associated type into metadatas, use the attribute `#[pallet::constant]`, e.g.:
/// ```ignore
/// #[pallet::config]
/// pub trait Config: frame_system::Config {
/// #[pallet::constant]
/// type Foo: Get<u32>;
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
/// }
/// ```
///
/// To bypass the `frame_system::Config` supertrait check, use the attribute
/// `#[pallet::disable_frame_system_supertrait_check]`, e.g.:
/// ```ignore
/// #[pallet::config]
/// #[pallet::disable_frame_system_supertrait_check]
/// pub trait Config: pallet_timestamp::Config {}
/// ```
///
/// ### Macro expansion:
///
/// The macro expand pallet constant metadata with the information given by `#[pallet::constant]`.
///
/// # Pallet struct placeholder: `#[pallet::pallet]` mandatory
///
/// The placeholder struct, on which is implemented pallet informations.
///
/// Item must be defined as followed:
/// ```ignore
/// #[pallet::pallet]
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
/// pub struct Pallet<T>(_);
/// ```
/// I.e. a regular struct definition named `Pallet`, with generic T and no where clause.
///
/// To generate a `Store` trait associating all storages, use the attribute
/// `#[pallet::generate_store($vis trait Store)]`, e.g.:
/// ```ignore
/// #[pallet::pallet]
/// #[pallet::generate_store(pub(super) trait Store)]
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
/// pub struct Pallet<T>(_);
/// ```
/// More precisely the store trait contains an associated type for each storage. It is implemented
/// for `Pallet` allowing to access the storage from pallet struct.
///
/// Thus when defining a storage named `Foo`, it can later be accessed from `Pallet` using
/// `<Pallet as Store>::Foo`.
///
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
/// To generate the full storage info (used for PoV calculation) use the attribute
/// `#[pallet::set_storage_max_encoded_len]`, e.g.:
/// ```ignore
/// #[pallet::pallet]
/// #[pallet::set_storage_max_encoded_len]
/// pub struct Pallet<T>(_);
/// ```
///
/// This require all storage to implement the trait [`traits::StorageInfoTrait`], thus all keys
/// and value types must bound [`pallet_prelude::MaxEncodedLen`].
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
///
/// ### Macro expansion:
///
/// The macro add this attribute to the struct definition:
/// ```ignore
/// #[derive(
/// frame_support::CloneNoBound,
/// frame_support::EqNoBound,
/// frame_support::PartialEqNoBound,
/// frame_support::RuntimeDebugNoBound,
/// )]
/// ```
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
/// and replace the type `_` by `PhantomData<T>`.
///
/// It implements on pallet:
/// * [`traits::GetPalletVersion`]
/// * [`traits::OnGenesis`]: contains some logic to write pallet version into storage.
/// * `ModuleErrorMetadata`: using error declared or no metadata.
///
/// It declare `type Module` type alias for `Pallet`, used by [`construct_runtime`].
///
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
/// It implements [`traits::PalletInfoAccess`] on `Pallet` to ease access to pallet informations
/// given by [`frame_support::traits::PalletInfo`].
/// (The implementation use the associated type `frame_system::Config::PalletInfo`).
///
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
/// It implements [`traits::StorageInfoTrait`] on `Pallet` which give information about all storages.
///
/// If the attribute generate_store is set then the macro creates the trait `Store` and implements
/// it on `Pallet`.
///
/// If the attribute set_storage_max_encoded_len is set then the macro call
/// [`traits::StorageInfoTrait`] for each storage in the implementation of
/// [`traits::StorageInfoTrait`] for the pallet.
/// Otherwise it implements [`traits::StorageInfoTrait`] for the pallet using the
/// [`traits::PartialStorageInfoTrait`] implementation of storages.
/// # Hooks: `#[pallet::hooks]` optional
///
/// Implementation of `Hooks` on `Pallet` allowing to define some specific pallet logic.
///
/// Item must be defined as
/// ```ignore
/// #[pallet::hooks]
/// impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> $optional_where_clause {
/// }
/// ```
/// I.e. a regular trait implementation with generic bound: `T: Config`, for the trait
/// `Hooks<BlockNumberFor<T>>` (they are defined in preludes), for the type `Pallet<T>`
/// and with an optional where clause.
///
/// If no `#[pallet::hooks]` exists, then a default implementation corresponding to the following
/// code is automatically generated:
/// ```ignore
/// #[pallet::hooks]
/// impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
/// ```
///
/// ### Macro expansion:
///
/// The macro implements the traits `OnInitialize`, `OnIdle`, `OnFinalize`, `OnRuntimeUpgrade`,
/// `OffchainWorker`, `IntegrityTest` using `Hooks` implementation.
///
/// NOTE: OnRuntimeUpgrade is implemented with `Hooks::on_runtime_upgrade` and some additional
/// logic. E.g. logic to write pallet version into storage.
///
/// NOTE: The macro also adds some tracing logic when implementing the above traits. The following
/// hooks emit traces: `on_initialize`, `on_finalize` and `on_runtime_upgrade`.
///
/// # Call: `#[pallet::call]` optional
///
/// Implementation of pallet dispatchables.
///
/// Item must be defined as:
/// ```ignore
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {
/// /// $some_doc
/// #[pallet::weight($ExpressionResultingInWeight)]
/// origin: OriginFor<T>,
/// $some_arg: $some_type,
/// // or with compact attribute: #[pallet::compact] $some_arg: $some_type,
/// ...
/// ) -> DispatchResultWithPostInfo { // or `-> DispatchResult`
/// ...
/// }
/// ...
/// }
/// ```
/// I.e. a regular type implementation, with generic `T: Config`, on type `Pallet<T>`, with
/// optional where clause.
///
/// Each dispatchable needs to define a weight with `#[pallet::weight($expr)]` attribute,
/// the first argument must be `origin: OriginFor<T>`, compact encoding for argument can be used
/// using `#[pallet::compact]`, function must return `DispatchResultWithPostInfo` or
/// `DispatchResult`.
///
/// All arguments must implement `Debug`, `PartialEq`, `Eq`, `Decode`, `Encode`, `Clone`. For ease
/// of use, bound the trait `Member` available in frame_support::pallet_prelude.
/// If no `#[pallet::call]` exists, then a default implementation corresponding to the following
/// code is automatically generated:
/// ```ignore
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {}
/// ```
///
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
/// **WARNING**: modifying dispatchables, changing their order, removing some must be done with
/// care. Indeed this will change the outer runtime call type (which is an enum with one variant
/// per pallet), this outer runtime call can be stored on-chain (e.g. in pallet-scheduler).
/// Thus migration might be needed.
///
/// ### Macro expansion
///
/// The macro create an enum `Call` with one variant per dispatchable. This enum implements:
/// `Clone`, `Eq`, `PartialEq`, `Debug` (with stripped implementation in `not("std")`), `Encode`,
/// `Decode`, `GetDispatchInfo`, `GetCallName`, `UnfilteredDispatchable`.
///
/// The macro implement on `Pallet`, the `Callable` trait and a function `call_functions` which
/// returns the dispatchable metadatas.
///
/// # Extra constants: `#[pallet::extra_constants]` optional
///
/// Allow to define some extra constants to put into constant metadata.
///
/// Item must be defined as:
/// ```ignore
/// #[pallet::extra_constants]
/// impl<T: Config> Pallet<T> where $optional_where_clause {
/// /// $some_doc
/// $vis fn $fn_name() -> $some_return_type {
/// ...
/// }
/// ...
/// }
/// ```
/// I.e. a regular rust implement block with some optional where clause and functions with 0 args,
/// 0 generics, and some return type.
///
/// ### Macro expansion
///
/// The macro add some extra constant to pallet constant metadata.
///
/// # Error: `#[pallet::error]` optional
///
/// Allow to define an error type to be return from dispatchable on error.
/// This error type informations are put into metadata.
///
/// Item must be defined as:
/// ```ignore
/// #[pallet::error]
/// pub enum Error<T> {
/// /// $some_optional_doc
/// $SomeFieldLessVariant,
/// ...
/// }
/// ```
/// I.e. a regular rust enum named `Error`, with generic `T` and fieldless variants.
/// The generic `T` mustn't bound anything and where clause is not allowed. But bounds and where
/// clause shouldn't be needed for any usecase.
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
///
/// ### Macro expansion
///
/// The macro implements `Debug` trait and functions `as_u8` using variant position, and `as_str`
/// using variant doc.
///
/// The macro implements `From<Error<T>>` for `&'static str`.
/// The macro implements `From<Error<T>>` for `DispatchError`.
///
/// The macro implements `ModuleErrorMetadata` on `Pallet` defining the `ErrorMetadata` of the
/// pallet.
///
/// # Event: `#[pallet::event]` optional
///
/// Allow to define pallet events, pallet events are stored in the block when they deposited (and
/// removed in next block).
///
/// Item is defined as:
/// ```ignore
/// #[pallet::event]
/// #[pallet::metadata($SomeType = "$Metadata", $SomeOtherType = "$Metadata", ..)] // Optional
/// #[pallet::generate_deposit($visibility fn deposit_event)] // Optional
/// pub enum Event<$some_generic> $optional_where_clause {
/// /// Some doc
/// $SomeName($SomeType, $YetanotherType, ...),
/// ...
/// }
/// ```
/// I.e. an enum (with named or unnamed fields variant), named Event, with generic: none or `T` or
/// `T: Config`, and optional where clause.
///
/// Each field must implement `Clone`, `Eq`, `PartialEq`, `Encode`, `Decode`, and `Debug` (on std
/// only).
/// For ease of use, bound the trait `Member` available in frame_support::pallet_prelude.
///
/// Variant documentations and field types are put into metadata.
/// The attribute `#[pallet::metadata(..)]` allows to specify the metadata to put for some types.
///
/// The metadata of a type is defined by:
/// * if matching a type in `#[pallet::metadata(..)]`, then the corresponding metadata.
/// * otherwise the type stringified.
///
/// E.g.:
/// ```ignore
/// #[pallet::event]
/// #[pallet::metadata(u32 = "SpecialU32")]
/// pub enum Event<T: Config> {
/// Proposed(u32, T::AccountId),
/// }
/// ```
/// will write in event variant metadata `"SpecialU32"` and `"T::AccountId"`.
///
/// The attribute `#[pallet::generate_deposit($visibility fn deposit_event)]` generate a helper
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
/// function on `Pallet` to deposit event.
///
/// NOTE: For instantiable pallet, event must be generic over T and I.
///
/// ### Macro expansion:
///
/// Macro will add on enum `Event` the attributes:
/// * `#[derive(frame_support::CloneNoBound)]`,
/// * `#[derive(frame_support::EqNoBound)]`,
/// * `#[derive(frame_support::PartialEqNoBound)]`,
/// * `#[derive(codec::Encode)]`,
/// * `#[derive(codec::Decode)]`,
/// * `#[derive(frame_support::RuntimeDebugNoBound)]`
///
/// Macro implements `From<Event<..>>` for ().
///
/// Macro implements metadata function on `Event` returning the `EventMetadata`.
///
/// If `#[pallet::generate_deposit]` then macro implement `fn deposit_event` on `Pallet`.
///
/// # Storage: `#[pallet::storage]` optional
///
/// Allow to define some abstract storage inside runtime storage and also set its metadata.
/// This attribute can be used multiple times.
///
/// Item is defined as:
/// ```ignore
/// #[pallet::storage]
/// #[pallet::getter(fn $getter_name)] // optional
/// $vis type $StorageName<$some_generic> $optional_where_clause
/// = $StorageType<$generic_name = $some_generics, $other_name = $some_other, ...>;
/// ```
/// or with unnamed generic
/// ```ignore
/// #[pallet::storage]
/// #[pallet::getter(fn $getter_name)] // optional
/// $vis type $StorageName<$some_generic> $optional_where_clause
/// = $StorageType<_, $some_generics, ...>;
/// ```
/// I.e. it must be a type alias, with generics: `T` or `T: Config`, aliased type must be one
/// of `StorageValue`, `StorageMap` or `StorageDoubleMap` (defined in frame_support).
/// The generic arguments of the storage type can be given in two manner: named and unnamed.
/// For named generic argument: the name for each argument is the one as define on the storage
/// struct:
/// * [`pallet_prelude::StorageValue`] expect `Value` and optionally `QueryKind` and `OnEmpty`,
/// * [`pallet_prelude::StorageMap`] expect `Hasher`, `Key`, `Value` and optionally `QueryKind` and
/// `OnEmpty`,
/// * [`pallet_prelude::StorageDoubleMap`] expect `Hasher1`, `Key1`, `Hasher2`, `Key2`, `Value` and
/// optionally `QueryKind` and `OnEmpty`.
///
/// For unnamed generic argument: Their first generic must be `_` as it is replaced by the macro
/// and other generic must declared as a normal declaration of type generic in rust.
///
/// The Prefix generic written by the macro is generated using `PalletInfo::name::<Pallet<..>>()`
/// and the name of the storage type.
/// E.g. if runtime names the pallet "MyExample" then the storage `type Foo<T> = ...` use the
/// prefix: `Twox128(b"MyExample") ++ Twox128(b"Foo")`.
///
/// The optional attribute `#[pallet::getter(fn $my_getter_fn_name)]` allow to define a
/// getter function on `Pallet`.
///
/// E.g:
/// ```ignore
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// pub(super) type MyStorage<T> = StorageMap<Hasher = Blake2_128Concat, Key = u32, Value = u32>;
/// ```
/// or
/// ```ignore
/// #[pallet::storage]
/// #[pallet::getter(fn my_storage)]
/// pub(super) type MyStorage<T> = StorageMap<_, Blake2_128Concat, u32, u32>;
/// ```
///
/// The optional attributes `#[cfg(..)]` allow conditional compilation for the storage.
///
/// E.g:
/// ```ignore
/// #[cfg(feature = "my-feature")]
/// #[pallet::storage]
/// pub(super) type MyStorage<T> = StorageValue<Value = u32>;
/// ```
///
/// All the `cfg` attributes are automatically copied to the items generated for the storage, i.e. the
/// getter, storage prefix, and the metadata element etc.
///
/// NOTE: If the `QueryKind` generic parameter is still generic at this stage or is using some type
/// alias then the generation of the getter might fail. In this case the getter can be implemented
/// manually.
///
/// NOTE: The generic `Hasher` must implement the [`StorageHasher`] trait (or the type is not
/// usable at all). We use [`StorageHasher::METADATA`] for the metadata of the hasher of the
/// storage item. Thus generic hasher is supported.
///
/// ### Macro expansion
///
/// For each storage item the macro generates a struct named
/// `_GeneratedPrefixForStorage$NameOfStorage`, and implements
/// [`StorageInstance`](traits::StorageInstance) on it using the pallet and storage name. It then
/// uses it as the first generic of the aliased type.
/// For named generic, the macro will reorder the generics, and remove the names.
/// The macro implements the function `storage_metadata` on `Pallet` implementing the metadata for
/// all storage items based on their kind:
/// * for a storage value, the type of the value is copied into the metadata
/// * for a storage map, the type of the values and the key's type is copied into the metadata
/// * for a storage double map, the type of the values, and the types of key1 and key2 are copied into
/// the metadata.
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
///
/// # Type value: `#[pallet::type_value]` optional
///
/// Helper to define a struct implementing `Get` trait. To ease use of storage types.
/// This attribute can be used multiple time.
///
/// Item is defined as
/// ```ignore
/// #[pallet::type_value]
/// fn $MyDefaultName<$some_generic>() -> $default_type $optional_where_clause { $expr }
/// ```
/// I.e.: a function definition with generics none or `T: Config` and a returned type.
///
/// E.g.:
/// ```ignore
/// #[pallet::type_value]
/// fn MyDefault<T: Config>() -> T::Balance { 3.into() }
/// ```
///
/// NOTE: This attribute is meant to be used alongside `#[pallet::storage]` to defined some
/// specific default value in storage.
///
/// ### Macro expansion
///
/// Macro renames the function to some internal name, generate a struct with the original name of
/// the function and its generic, and implement `Get<$ReturnType>` by calling the user defined
/// function.
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
///
/// # Genesis config: `#[pallet::genesis_config]` optional
///
/// Allow to define the genesis configuration of the pallet.
///
/// Item is defined as either an enum or a struct.
/// It needs to be public and implement trait GenesisBuild with `#[pallet::genesis_build]`.
/// The type generics is constrained to be either none, or `T` or `T: Config`.
///
/// E.g:
/// ```ignore
/// #[pallet::genesis_config]
/// pub struct GenesisConfig<T: Config> {
/// _myfield: BalanceOf<T>,
/// }
/// ```
///
/// ### Macro expansion
///
/// Macro will add the following attribute on it:
/// * `#[cfg(feature = "std")]`
/// * `#[derive(Serialize, Deserialize)]`
/// * `#[serde(rename_all = "camelCase")]`
/// * `#[serde(deny_unknown_fields)]`
/// * `#[serde(bound(serialize = ""))]`
/// * `#[serde(bound(deserialize = ""))]`
///
/// # Genesis build: `#[pallet::genesis_build]` optional
///
/// Allow to define how genesis_configuration is built.
///
/// Item is defined as
/// ```ignore
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig<$maybe_generics> {
/// fn build(&self) { $expr }
/// }
/// ```
/// I.e. a rust trait implementation with generic `T: Config`, of trait `GenesisBuild<T>` on type
/// `GenesisConfig` with generics none or `T`.
///
/// E.g.:
/// ```ignore
/// #[pallet::genesis_build]
/// impl<T: Config> GenesisBuild<T> for GenesisConfig {
/// fn build(&self) {}
/// }
/// ```
///
/// ### Macro expansion
///
/// Macro will add the following attribute on it:
/// * `#[cfg(feature = "std")]`
///
/// Macro will implement `sp_runtime::BuildModuleGenesisStorage` using `()` as second generic for
/// non-instantiable pallets.
///
/// # Inherent: `#[pallet::inherent]` optional
///
/// Allow the pallet to provide some inherent:
///
/// Item is defined as:
/// ```ignore
/// #[pallet::inherent]
/// impl<T: Config> ProvideInherent for Pallet<T> {
/// // ... regular trait implementation
/// }
/// ```
/// I.e. a trait implementation with bound `T: Config`, of trait `ProvideInherent` for type
/// `Pallet<T>`, and some optional where clause.
///
/// ### Macro expansion
///
/// Macro make currently no use of this information, but it might use this information in the
/// future to give information directly to construct_runtime.
///
/// # Validate unsigned: `#[pallet::validate_unsigned]` optional
///
/// Allow the pallet to validate some unsigned transaction:
///
/// Item is defined as:
/// ```ignore
/// #[pallet::validate_unsigned]
/// impl<T: Config> ValidateUnsigned for Pallet<T> {
/// // ... regular trait implementation
/// }
/// ```
/// I.e. a trait implementation with bound `T: Config`, of trait `ValidateUnsigned` for type
/// `Pallet<T>`, and some optional where clause.
///
/// NOTE: There is also `sp_runtime::traits::SignedExtension` that can be used to add some specific
/// logic for transaction validation.
///
/// ### Macro expansion
///
/// Macro make currently no use of this information, but it might use this information in the
/// future to give information directly to construct_runtime.
///
/// # Origin: `#[pallet::origin]` optional
///
/// Allow to define some origin for the pallet.
///
/// Item must be either a type alias or an enum or a struct. It needs to be public.
///
/// E.g.:
/// ```ignore
/// #[pallet::origin]
/// pub struct Origin<T>(PhantomData<(T)>);
/// ```
///
/// **WARNING**: modifying origin changes the outer runtime origin. This outer runtime origin can
/// be stored on-chain (e.g. in pallet-scheduler), thus any change must be done with care as it
/// might require some migration.
///
/// NOTE: for instantiable pallet, origin must be generic over T and I.
///
/// # General notes on instantiable pallet
///
/// An instantiable pallet is one where Config is generic, i.e. `Config<I>`. This allow runtime to
/// implement multiple instance of the pallet, by using different type for the generic.
/// This is the sole purpose of the generic `I`.
/// But because `PalletInfo` requires `Pallet` placeholder to be static it is important to bound
/// `'static` whenever `PalletInfo` can be used.
/// And in order to have instantiable pallet usable as a regular pallet without instance, it is
/// important to bound `= ()` on every types.
///
/// Thus impl bound look like `impl<T: Config<I>, I: 'static>`, and types look like
/// `SomeType<T, I=()>` or `SomeType<T: Config<I>, I: 'static = ()>`.
///
/// # Example for pallet without instance.
///
/// ```
/// pub use pallet::*; // reexport in crate namespace for `construct_runtime!`
///
/// #[frame_support::pallet]
/// // NOTE: The name of the pallet is provided by `construct_runtime` and is used as
/// // the unique identifier for the pallet's storage. It is not defined in the pallet itself.
/// pub mod pallet {
/// use frame_support::pallet_prelude::*; // Import various types used in the pallet definition
/// use frame_system::pallet_prelude::*; // Import some system helper types.
///
/// type BalanceOf<T> = <T as Config>::Balance;
///
/// // Define the generic parameter of the pallet
/// // The macro parses `#[pallet::constant]` attributes and uses them to generate metadata
/// // for the pallet's constants.
/// #[pallet::config]
/// pub trait Config: frame_system::Config {
/// #[pallet::constant] // put the constant in metadata
/// type MyGetParam: Get<u32>;
/// type Balance: Parameter + From<u8>;
/// type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
/// }
///
/// // Define some additional constant to put into the constant metadata.
/// #[pallet::extra_constants]
/// impl<T: Config> Pallet<T> {
/// /// Some description
/// fn exra_constant_name() -> u128 { 4u128 }
/// }
///
/// // Define the pallet struct placeholder, various pallet function are implemented on it.
/// #[pallet::pallet]
/// #[pallet::generate_store(pub(super) trait Store)]
![thiolliere thiolliere's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
thiolliere
committed
/// pub struct Pallet<T>(_);
/// #[pallet::hooks]
/// impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
/// fn on_initialize(_n: BlockNumberFor<T>) -> Weight {
/// unimplemented!();
/// }
///
/// // can implement also: on_finalize, on_runtime_upgrade, offchain_worker, ...
/// // see `Hooks` trait
/// }
///
/// // Declare Call struct and implement dispatchables.
/// //
/// // WARNING: Each parameter used in functions must implement: Clone, Debug, Eq, PartialEq,
/// // Codec.
/// //
/// // The macro parses `#[pallet::compact]` attributes on function arguments and implements
/// // the `Call` encoding/decoding accordingly.
/// #[pallet::call]
/// impl<T: Config> Pallet<T> {
/// /// Doc comment put in metadata
/// #[pallet::weight(0)] // Defines weight for call (function parameters are in scope)
/// origin: OriginFor<T>,
/// ) -> DispatchResultWithPostInfo {
/// let _ = origin;
/// unimplemented!();
/// }
/// }
///
/// // Declare the pallet `Error` enum (this is optional).
/// // The macro generates error metadata using the doc comment on each variant.
/// #[pallet::error]
/// pub enum Error<T> {
/// /// doc comment put into metadata
/// InsufficientProposersBalance,
/// }
///
/// // Declare pallet Event enum (this is optional).
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
/// //
/// // WARNING: Each type used in variants must implement: Clone, Debug, Eq, PartialEq, Codec.
/// //
/// // The macro generates event metadata, and derive Clone, Debug, Eq, PartialEq and Codec
/// #[pallet::event]
/// // Additional argument to specify the metadata to use for given type.
/// #[pallet::metadata(BalanceOf<T> = "Balance", u32 = "Other")]
/// // Generate a funciton on Pallet to deposit an event.
/// #[pallet::generate_deposit(pub(super) fn deposit_event)]
/// pub enum Event<T: Config> {
/// /// doc comment put in metadata
/// // `<T as frame_system::Config>::AccountId` is not defined in metadata list, the last
/// // Thus the metadata is `<T as frame_system::Config>::AccountId`.
/// Proposed(<T as frame_system::Config>::AccountId),
/// /// doc
/// // here metadata will be `Balance` as define in metadata list
/// Spending(BalanceOf<T>),
/// // here metadata will be `Other` as define in metadata list
/// Something(u32),
/// }
///
/// // Define a struct which implements `frame_support::traits::Get<T::Balance>` (optional).