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Module iota::module_metadata

On-chain metadata associated with a single module of a package.

A ModuleMetadata is a key-value store backed by dynamic fields, where each value holds a particular kind of module metadata (e.g. authenticator or view function information). Instances are owned by the package's iota::package_metadata::PackageMetadataV1 object.

use iota::address;
use iota::derived_object;
use iota::dynamic_field;
use iota::hex;
use iota::object;
use iota::tx_context;
use std::ascii;
use std::bcs;
use std::option;
use std::string;
use std::vector;

Module Functions​

pub(pkg) new​

Creates a new, empty module_metadata

The object address is derived from the owning package id together with the module name, so that each module in a package gets a distinct ModuleMetadata (and therefore distinct dynamic field children), and that the same module name in different packages does not collide.

public(package) fun new(package_storage_id: iota::object::ID, module_name: std::ascii::String): iota::module_metadata::ModuleMetadata
Implementation
public(package) fun new(package_storage_id: ID, module_name: ascii::String): ModuleMetadata {
    let id_address = derived_object::derive_address(
        package_storage_id,
        ModuleMetadataKey(module_name),
    );
    let id = object::new_uid_from_hash(id_address);
    ModuleMetadata {
        id,
        size: 0,
    }
}

Structs​

struct ModuleMetadata​

public struct ModuleMetadata has key, store
Fields
id: iota::object::UID

the ID of this module_metadata

size: u64

the number of key-value pairs in the module_metadata

pub borrow_view_functions_metadata_v1​

Borrows the list of view function names recorded for the module.

public fun borrow_view_functions_metadata_v1(self: &iota::module_metadata::ModuleMetadata): &vector<std::ascii::String>
Implementation

pub contains_view_functions_metadata_v1​

Returns true iff the module has recorded view function metadata.

public fun contains_view_functions_metadata_v1(self: &iota::module_metadata::ModuleMetadata): bool
Implementation

pub is_empty​

Returns true iff the module_metadata is empty (if length returns 0)

public fun is_empty(self: &iota::module_metadata::ModuleMetadata): bool
Implementation
public fun is_empty(self: &ModuleMetadata): bool {
    self.size == 0
}

pub is_view_function_v1​

Returns true iff function_name is one of the module's view functions.

public fun is_view_function_v1(self: &iota::module_metadata::ModuleMetadata, function_name: &std::ascii::String): bool
Implementation
public fun is_view_function_v1(self: &ModuleMetadata, function_name: &ascii::String): bool {
    let view_functions_metadata = self.borrow_view_functions_metadata_v1();
    view_functions_metadata.find_index!(|s| s == *function_name).is_some()
}

pub length​

Returns the size of the module_metadata, the number of key-value pairs

public fun length(self: &iota::module_metadata::ModuleMetadata): u64
Implementation
public fun length(self: &ModuleMetadata): u64 {
    self.size
}

pub(pkg) add​

Adds a key-value pair to the module metadata. Aborts with iota::dynamic_field::EFieldAlreadyExists if an entry for k already exists.

public(package) fun add<K: copy, drop, store, V: store>(self: &mut iota::module_metadata::ModuleMetadata, k: K, v: V)
Implementation
public(package) fun add<K: copy + drop + store, V: store>(self: &mut ModuleMetadata, k: K, v: V) {
    field::add(&mut self.id, k, v);
    self.size = self.size + 1;
}

pub(pkg) add_view_function_metadata_v1​

Records the list of view function names for the module.

public(package) fun add_view_function_metadata_v1(self: &mut iota::module_metadata::ModuleMetadata, view_function_names: vector<std::ascii::String>)
Implementation
public(package) fun add_view_function_metadata_v1(
    self: &mut ModuleMetadata,
    view_function_names: vector<ascii::String>,
) {
    self.add(
        ViewFunctionMetadataV1FieldName {},
        view_function_names,
    );
}

pub(pkg) borrow​

Immutably borrows the value associated with k. Aborts with iota::dynamic_field::EFieldDoesNotExist if no entry for k exists. Aborts with iota::dynamic_field::EFieldTypeMismatch if the value is not of type V.

public(package) fun borrow<K: copy, drop, store, V: store>(self: &iota::module_metadata::ModuleMetadata, k: K): &V
Implementation
public(package) fun borrow<K: copy + drop + store, V: store>(self: &ModuleMetadata, k: K): &V {
    field::borrow(&self.id, k)
}

pub(pkg) borrow_mut​

Mutably borrows the value associated with k. Aborts with iota::dynamic_field::EFieldDoesNotExist if no entry for k exists. Aborts with iota::dynamic_field::EFieldTypeMismatch if the value is not of type V.

public(package) fun borrow_mut<K: copy, drop, store, V: store>(self: &mut iota::module_metadata::ModuleMetadata, k: K): &mut V
Implementation
public(package) fun borrow_mut<K: copy + drop + store, V: store>(
    self: &mut ModuleMetadata,
    k: K,
): &mut V {
    field::borrow_mut(&mut self.id, k)
}

pub(pkg) contains​

Returns true iff there is a value associated with k.

public(package) fun contains<K: copy, drop, store>(self: &iota::module_metadata::ModuleMetadata, k: K): bool
Implementation
public(package) fun contains<K: copy + drop + store>(self: &ModuleMetadata, k: K): bool {
    field::exists_<K>(&self.id, k)
}

pub(pkg) contains_with_type​

Returns true iff there is a value of type V associated with k.

public(package) fun contains_with_type<K: copy, drop, store, V: store>(self: &iota::module_metadata::ModuleMetadata, k: K): bool
Implementation
public(package) fun contains_with_type<K: copy + drop + store, V: store>(
    self: &ModuleMetadata,
    k: K,
): bool {
    field::exists_with_type<K, V>(&self.id, k)
}

pub(pkg) remove​

Removes the entry for k and returns its value. Aborts with iota::dynamic_field::EFieldDoesNotExist if no entry for k exists. Aborts with iota::dynamic_field::EFieldTypeMismatch if the value is not of type V.

public(package) fun remove<K: copy, drop, store, V: store>(self: &mut iota::module_metadata::ModuleMetadata, k: K): V
Implementation
public(package) fun remove<K: copy + drop + store, V: store>(self: &mut ModuleMetadata, k: K): V {
    let v = field::remove(&mut self.id, k);
    self.size = self.size - 1;
    v
}

struct ModuleMetadataKey​

Key used to derive the address of a ModuleMetadata object from the owning package id and the module name.

public struct ModuleMetadataKey has copy, drop, store
Fields

struct ViewFunctionMetadataV1FieldName​

Dynamic field key for the list of view function names of the module.

public struct ViewFunctionMetadataV1FieldName has copy, drop, store
Fields