Module frame_support::traits

Traits and associated utilities for use in the FRAME environment.

NOTE: If you’re looking for parameter_types, it has moved in to the top-level module.

Re-exports

• pub use tokens::currency::ActiveIssuanceOf;
• pub use tokens::currency::Currency;
• pub use tokens::currency::LockIdentifier;
• pub use tokens::currency::LockableCurrency;
• pub use tokens::currency::NamedReservableCurrency;
• pub use tokens::currency::ReservableCurrency;
• pub use tokens::currency::TotalIssuanceOf;
• pub use tokens::currency::VestingSchedule;
• pub use tokens::fungible;
• pub use tokens::fungibles;
• pub use tokens::imbalance::Imbalance;
• pub use tokens::imbalance::OnUnbalanced;
• pub use tokens::imbalance::SignedImbalance;
• pub use tokens::nonfungible;
• pub use tokens::nonfungibles;
• pub use tokens::BalanceStatus;
• pub use tokens::ExistenceRequirement;
• pub use tokens::Locker;
• pub use tokens::WithdrawReasons;

Modules

• defensive_prelude
  Prelude module for all defensive traits to be imported at once.
• schedule
  Traits and associated utilities for scheduling dispatchables in FRAME.
• tokens
  Traits for working with tokens and their associated datastructures.

Structs

• AsContains
  Adapter struct for turning an OrderedMembership impl into a Contains impl.
• AsEnsureOriginWithArg
• Backing
  Some amount of backing from a group. The precise definition of what it means to “back” something is left flexible.
• CallMetadata
  The function and pallet name of the Call.
• ClassCountOf
• ClearFilterGuard
  Guard type for clearing all pushed constraints from a FilterStack and reinstating them when dropped.
• ConstBool
  Const getter for a basic type.
• ConstI8
  Const getter for a basic type.
• ConstI16
  Const getter for a basic type.
• ConstI32
  Const getter for a basic type.
• ConstI64
  Const getter for a basic type.
• ConstI128
  Const getter for a basic type.
• ConstU8
  Const getter for a basic type.
• ConstU16
  Const getter for a basic type.
• ConstU32
  Const getter for a basic type.
• ConstU64
  Const getter for a basic type.
• ConstU128
  Const getter for a basic type.
• CrateVersion
  The version of a crate.
• EitherOf
  “OR gate” implementation of EnsureOrigin, Success type for both L and R must be equal.
• EitherOfDiverse
  “OR gate” implementation of EnsureOrigin allowing for different Success types for L and R, with them combined using an Either type.
• EnsureOriginEqualOrHigherPrivilege
  EnsureOrigin implementation that checks that an origin has equal or higher privilege compared to the expected Origin.
• EqualPrivilegeOnly
  Implementation of PrivilegeCmp that only checks for equal origins.
• EverythingBut
  A Contains implementation that contains everything except the values in Exclude.
• FilterStackGuard
  Guard type for pushing a constraint to a FilterStack and popping when dropped.
• Footprint
  The resource footprint of a queue.
• FromContainsPair
  Converter struct to use a ContainsPair implementation for a Contains bound.
• GetDefault
  Implement Get by returning Default for any type that implements Default.
• InsideBoth
  A Contains implementation which contains all members of These which are also members of Those.
• IsInVec
  Trivial utility for implementing Contains/OrderedMembership with a Vec.
• MapSuccess
  A derivative EnsureOrigin implementation. It mutates the Success result of an Original implementation with a given Mutator.
• NeverEnsureOrigin
  EnsureOrigin implementation that always fails.
• PalletInfoData
  Information regarding an instance of a pallet.
• SaturatingCurrencyToVote
  A naive implementation of CurrencyConvert that simply saturates all conversions.
• StorageInfo
  Metadata about storage from the runtime.
• StorageMapShim
  A shim for placing around a storage item in order to use it as a StoredValue. Ideally this wouldn’t be needed as StorageValues should blanket implement StoredValues, however this would break the ability to have custom impls of StoredValue. The other workaround is to implement it directly in the macro.
• StorageVersion
  The storage version of a pallet.
• TheseExcept
  A Contains implementation that contains all members of These excepting any members in Except.
• TrackedStorageKey
  Storage key with read/write tracking information.
• TryMapSuccess
  A derivative EnsureOrigin implementation. It mutates the Success result of an Original implementation with a given Mutator, allowing the possibility of an error to be returned from the mutator.
• U128CurrencyToVote
  An implementation of CurrencyToVote tailored for chain’s that have a balance type of u128.
• WrapperKeepOpaque
  A wrapper for any type T which implement encode/decode in a way compatible with Vec<u8>.
• WrapperOpaque
  A wrapper for any type T which implement encode/decode in a way compatible with Vec<u8>.

Enums

• Bounded
• Everything
  A Contains implementation that contains every value.
• ExecuteOverweightError
  Errors that can happen when attempting to execute an overweight message with ServiceQueues::execute_overweight().
• Nothing
  A Contains implementation that contains no value.
• PollStatus
• ProcessMessageError
  Errors that can happen when attempting to process a message with ProcessMessage::process_message().
• SameOrOther
  Return type used when we need to return one of two items, each of the opposite direction or sign, with one (Same) being of the same type as the self or primary argument of the function that returned it.

Constants

• STORAGE_VERSION_STORAGE_KEY_POSTFIX
  The storage key postfix that is used to store the StorageVersion per pallet.

Traits

• CallerTrait
  The trait implemented by the overarching enumeration of the different pallets’ origins. Unlike OriginTrait impls, this does not include any kind of dispatch/call filter. Also, this trait is more flexible in terms of how it can be used: it is a Parameter and Member, so it can be used as dispatchable parameters as well as in storage items.
• ChangeMembers
  Trait for type that can handle incremental changes to a set of account IDs.
• Contains
  A trait for querying whether a type can be said to “contain” a value.
• ContainsLengthBound
  A trait for querying bound for the length of an implementation of Contains
• ContainsPair
  A trait for querying whether a type can be said to “contain” a pair-value.
• CurrencyToVote
  A trait similar to Convert to convert values from B an abstract balance type into u64 and back from u128. (This conversion is used in election and other places where complex calculation over balance type is needed)
• Defensive
  A trait to handle errors and options when you are really sure that a condition must hold, but not brave enough to expect on it, or a default fallback value makes more sense.
• DefensiveMax
  Defensively calculates the maximum of two values.
• DefensiveMin
  Defensively calculates the minimum of two values.
• DefensiveOption
  Subset of methods similar to Defensive that can only work for a Option.
• DefensiveResult
  Subset of methods similar to Defensive that can only work for a Result.
• DefensiveSaturating
  A variant of Defensive with the same rationale, for the arithmetic operations where in case an infallible operation fails, it saturates.
• DefensiveTruncateFrom
  Construct an object by defensively truncating an input if the TryFrom conversion fails.
• DisabledValidators
  Trait used to check whether a given validator is currently disabled and should not be participating in consensus (e.g. because they equivocated).
• EnqueueMessage
  Can enqueue messages for multiple origins.
• EnsureInherentsAreFirst
  A trait to ensure the inherent are before non-inherent in a block.
• EnsureOrigin
  Some sort of check on the origin is performed by this object.
• EnsureOriginWithArg
  Some sort of check on the origin is performed by this object.
• EstimateCallFee
  Something that can estimate the fee of a (frame-based) call.
• EstimateNextNewSession
  Something that can estimate at which block scheduling of the next session will happen (i.e when we will try to fetch new validators).
• EstimateNextSessionRotation
  Something that can estimate at which block the next session rotation will happen (i.e. a new session starts).
• ExecuteBlock
  Something that can execute a given block.
• ExtrinsicCall
  An extrinsic on which we can get access to call.
• FilterDeprecated
• FilterStack
  Trait to add a constraint onto the filter.
• FindAuthor
  A trait for finding the author of a block header based on the PreRuntime digests contained within it.
• GenesisBuild
  A trait to define the build function of a genesis config, T and I are placeholder for pallet trait and pallet instance.
• Get
  A trait for querying a single value from a type.
• GetBacking
  Retrieve the backing from an object’s ref.
• GetCallMetadata
  Gets the metadata for the Call - function name and pallet name.
• GetCallName
  Gets the function name of the Call.
• GetStorageVersion
  Provides information about the storage version of a pallet.
• HandleLifetime
  A simple, generic one-parameter event notifier/handler.
• Hooks
  The pallet hooks trait. Implementing this lets you express some logic to execute.
• InitializeMembers
  Trait for type that can handle the initialization of account IDs at genesis.
• Instance
  An instance of a pallet in the storage.
• InstanceFilter
  Simple trait for providing a filter over a reference to some type, given an instance of itself.
• IntegrityTest
  Type that provide some integrity tests.
• IsSubType
  Something that can be checked to be a of sub type T.
• IsType
  Trait to be used when types are exactly same.
• KeyOwnerProofSystem
  Something which can compute and check proofs of a historical key owner and return full identification data of that key owner.
• Lateness
  Trait to be used by block producing consensus engine modules to determine how late the current block is (e.g. in a slot-based proposal mechanism how many slots were skipped since the previous block).
• Len
  Anything that can have a ::len() method.
• OffchainWorker
  Off-chain computation trait.
• OnFinalize
  The block finalization trait.
• OnGenesis
  A trait that will be called at genesis.
• OnIdle
  The block’s on idle trait.
• OnInitialize
  The block initialization trait.
• OnKilledAccount
  The account with the given id was reaped.
• OnNewAccount
  Handler for when a new account has been created.
• OnRuntimeUpgrade
  The runtime upgrade trait.
• OnTimestampSet
  A trait which is called when the timestamp is set in the runtime.
• OneSessionHandler
  A session handler for specific key type.
• OriginTrait
  Methods available on frame_system::Config::RuntimeOrigin.
• PalletError
  Trait indicating that the implementing type is going to be included as a field in a variant of the #[pallet::error] enum type.
• PalletInfo
  Provides information about the pallet itself and its setup in the runtime.
• PalletInfoAccess
  Provides information about the pallet itself and its setup in the runtime.
• PalletsInfoAccess
  Provide information about a bunch of pallets.
• PartialStorageInfoTrait
  Similar to StorageInfoTrait, a trait to give partial information about storage.
• Polling
• PreimageProvider
  A interface for looking up preimages from their hash on chain.
• PreimageRecipient
  A interface for managing preimages to hashes on chain.
• PrivilegeCmp
  Something that can compare privileges of two origins.
• ProcessMessage
  Can process messages from a specific origin.
• QueryPreimage
  A interface for looking up preimages from their hash on chain.
• Randomness
  A trait that is able to provide randomness.
• ServiceQueues
  Can service queues and execute overweight messages.
• SortedMembers
  A trait for a set which can enumerate its members in order.
• StorageInfoTrait
  A trait to give information about storage.
• StorageInstance
  An instance of a storage in a pallet.
• StorePreimage
  A interface for managing preimages to hashes on chain.
• StoredMap
  An abstraction of a value stored within storage, but possibly as part of a larger composite item.
• Time
• TryCollect
  Try and collect into a collection C.
• TryDrop
  A type for which some values make sense to be able to drop without further consideration.
• TypedGet
  A trait for querying a single value from a type defined in the trait.
• UnfilteredDispatchable
  Type that can be dispatched with an origin but without checking the origin filter.
• UnixTime
  Trait to deal with unix time.
• ValidatorRegistration
  Implementors of this trait provide information about whether or not some validator has been registered with them. The Session module is an implementor.
• ValidatorSet
  A trait for online node inspection in a session.
• ValidatorSetWithIdentification
  ValidatorSet combined with an identification.
• VerifySeal
  A trait for verifying the seal of a header and returning the author.
• VoteTally
• WhitelistedStorageKeys
  Allows a pallet to specify storage keys to whitelist during benchmarking. This means those keys will be excluded from the benchmarking performance calculation.

Type Definitions

• AllowAllDeprecated
• BoundedInline
• DenyAllDeprecated
• EnsureOneOfDeprecated
  “OR gate” implementation of EnsureOrigin allowing for different Success types for L and R, with them combined using an Either type.
• FetchResult
• Hash