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Module 0x2::object

Iota object identifiers

use 0x1::bcs;
use 0x2::address;
use 0x2::tx_context;

Struct ID​

An object ID. This is used to reference Iota Objects. This is not guaranteed to be globally unique--anyone can create an ID from a UID or from an object, and ID's can be freely copied and dropped. Here, the values are not globally unique because there can be multiple values of type ID with the same underlying bytes. For example, object::id(&obj) can be called as many times as you want for a given obj, and each ID value will be identical.

struct ID has copy, drop, store
Fields
bytes: address

Struct UID​

Globally unique IDs that define an object's ID in storage. Any Iota Object, that is a struct with the key ability, must have id: UID as its first field. These are globally unique in the sense that no two values of type UID are ever equal, in other words for any two values id1: UID and id2: UID, id1 != id2. This is a privileged type that can only be derived from a TxContext. UID doesn't have the drop ability, so deleting a UID requires a call to delete.

struct UID has store
Fields

Constants​

Sender is not @0x0 the system address.

const ENotSystemAddress: u64 = 0;

The hardcoded ID for the singleton AuthenticatorState Object.

const IOTA_AUTHENTICATOR_STATE_ID: address = 7;

The hardcoded ID for the Bridge Object.

const IOTA_BRIDGE_ID: address = 9;

The hardcoded ID for the singleton Clock Object.

const IOTA_CLOCK_OBJECT_ID: address = 6;

The hardcoded ID for the singleton DenyList.

const IOTA_DENY_LIST_OBJECT_ID: address = 403;

The hardcoded ID for the singleton Random Object.

const IOTA_RANDOM_ID: address = 8;

The hardcoded ID for the singleton Iota System State Object.

const IOTA_SYSTEM_STATE_OBJECT_ID: address = 5;

Function id_to_bytes​

Get the raw bytes of a ID

public fun id_to_bytes(id: &object::ID): vector<u8>
Implementation
public fun id_to_bytes(id: &ID): vector<u8> {
bcs::to_bytes(&id.bytes)
}

Function id_to_address​

Get the inner bytes of id as an address.

public fun id_to_address(id: &object::ID): address
Implementation
public fun id_to_address(id: &ID): address {
id.bytes
}

Function id_from_bytes​

Make an ID from raw bytes.

public fun id_from_bytes(bytes: vector<u8>): object::ID
Implementation
public fun id_from_bytes(bytes: vector<u8>): ID {
address::from_bytes(bytes).to_id()
}

Function id_from_address​

Make an ID from an address.

public fun id_from_address(bytes: address): object::ID
Implementation
public fun id_from_address(bytes: address): ID {
ID { bytes }
}

Function iota_system_state​

Create the UID for the singleton IotaSystemState object. This should only be called once from iota_system.

fun iota_system_state(ctx: &tx_context::TxContext): object::UID
Implementation
fun iota_system_state(ctx: &TxContext): UID {
assert!(ctx.sender() == @0x0, ENotSystemAddress);
UID {
id: ID { bytes: IOTA_SYSTEM_STATE_OBJECT_ID },
}
}

Function clock​

Create the UID for the singleton Clock object. This should only be called once from clock.

public(friend) fun clock(): object::UID
Implementation
public(package) fun clock(): UID {
UID {
id: ID { bytes: IOTA_CLOCK_OBJECT_ID }
}
}

Function authenticator_state​

Create the UID for the singleton AuthenticatorState object. This should only be called once from authenticator_state.

public(friend) fun authenticator_state(): object::UID
Implementation
public(package) fun authenticator_state(): UID {
UID {
id: ID { bytes: IOTA_AUTHENTICATOR_STATE_ID }
}
}

Function randomness_state​

Create the UID for the singleton Random object. This should only be called once from random.

public(friend) fun randomness_state(): object::UID
Implementation
public(package) fun randomness_state(): UID {
UID {
id: ID { bytes: IOTA_RANDOM_ID }
}
}

Function iota_deny_list_object_id​

Create the UID for the singleton DenyList object. This should only be called once from deny_list.

public(friend) fun iota_deny_list_object_id(): object::UID
Implementation
public(package) fun iota_deny_list_object_id(): UID {
UID {
id: ID { bytes: IOTA_DENY_LIST_OBJECT_ID }
}
}

Function bridge​

Create the UID for the singleton Bridge object. This should only be called once from bridge.

fun bridge(): object::UID
Implementation
fun bridge(): UID {
UID {
id: ID { bytes: IOTA_BRIDGE_ID }
}
}

Function uid_as_inner​

Get the inner ID of uid

public fun uid_as_inner(uid: &object::UID): &object::ID
Implementation
public fun uid_as_inner(uid: &UID): &ID {
&uid.id
}

Function uid_to_inner​

Get the raw bytes of a uid's inner ID

public fun uid_to_inner(uid: &object::UID): object::ID
Implementation
public fun uid_to_inner(uid: &UID): ID {
uid.id
}

Function uid_to_bytes​

Get the raw bytes of a UID

public fun uid_to_bytes(uid: &object::UID): vector<u8>
Implementation
public fun uid_to_bytes(uid: &UID): vector<u8> {
bcs::to_bytes(&uid.id.bytes)
}

Function uid_to_address​

Get the inner bytes of id as an address.

public fun uid_to_address(uid: &object::UID): address
Implementation
public fun uid_to_address(uid: &UID): address {
uid.id.bytes
}

Function new​

Create a new object. Returns the UID that must be stored in a Iota object. This is the only way to create UIDs.

public fun new(ctx: &mut tx_context::TxContext): object::UID
Implementation
public fun new(ctx: &mut TxContext): UID {
UID {
id: ID { bytes: ctx.fresh_object_address() },
}
}

Function delete​

Delete the object and it's UID. This is the only way to eliminate a UID.

public fun delete(id: object::UID)
Implementation
public fun delete(id: UID) {
let UID { id: ID { bytes } } = id;
delete_impl(bytes)
}

Function id​

Get the underlying ID of obj

public fun id<T: key>(obj: &T): object::ID
Implementation
public fun id<T: key>(obj: &T): ID {
borrow_uid(obj).id
}

Function borrow_id​

Borrow the underlying ID of obj

public fun borrow_id<T: key>(obj: &T): &object::ID
Implementation
public fun borrow_id<T: key>(obj: &T): &ID {
&borrow_uid(obj).id
}

Function id_bytes​

Get the raw bytes for the underlying ID of obj

public fun id_bytes<T: key>(obj: &T): vector<u8>
Implementation
public fun id_bytes<T: key>(obj: &T): vector<u8> {
bcs::to_bytes(&borrow_uid(obj).id)
}

Function id_address​

Get the inner bytes for the underlying ID of obj

public fun id_address<T: key>(obj: &T): address
Implementation
public fun id_address<T: key>(obj: &T): address {
borrow_uid(obj).id.bytes
}

Function borrow_uid​

Get the UID for obj. Safe because Iota has an extra bytecode verifier pass that forces every struct with the key ability to have a distinguished UID field. Cannot be made public as the access to UID for a given object must be privileged, and restrictable in the object's module.

fun borrow_uid<T: key>(obj: &T): &object::UID
Implementation
native fun borrow_uid<T: key>(obj: &T): &UID;

Function new_uid_from_hash​

Generate a new UID specifically used for creating a UID from a hash

public(friend) fun new_uid_from_hash(bytes: address): object::UID
Implementation
public(package) fun new_uid_from_hash(bytes: address): UID {
record_new_uid(bytes);
UID { id: ID { bytes } }
}

Function delete_impl​

fun delete_impl(id: address)
Implementation
native fun delete_impl(id: address);

Function record_new_uid​

fun record_new_uid(id: address)
Implementation
native fun record_new_uid(id: address);