Struct structural::field::ownership::MovedOutFields

pub struct MovedOutFields(_);

Which fields have been moved out of a value.

This is used to implement converting a value into multiple fields by value.

Example

This is a toy example, for more realistic examples,you can look at the manual implementation example of IntoField ,or the manual implementation example of IntoVariantField .

use structural::field::{MovedOutFields, FieldBit};

// This is how `FieldBit` is constructed in the derive macro.
const FIELD_A_BIT: FieldBit= FieldBit::new(0);
const FIELD_B_BIT: FieldBit= FieldBit::new(1);

let mut moved = MovedOutFields::new();

// A `MovedOutFields` considers no field moved when constructed.
assert!( !moved.is_moved_out(FIELD_A_BIT) );
assert!( !moved.is_moved_out(FIELD_B_BIT) );

// `set_moved_out` is called in the
// `IntoField::move_out_field_`/`IntoVariantField::move_out_vfield_` implementation.
moved.set_moved_out(FIELD_A_BIT);
moved.set_moved_out(FIELD_B_BIT);

// `is_moved_out` is called in the `DropFields::drop_fields` implementation,
//
// If `is_moved_out` returns false, then a field has not been moved out,
// and must be dropped.
assert!( moved.is_moved_out(FIELD_A_BIT) );
assert!( moved.is_moved_out(FIELD_B_BIT) );

Implementations

impl MovedOutFields

pub const fn new() -> Self

Constructs a MovedOutFields where no field is considered moved out yet.

pub fn set_moved_out(&mut self, bit: FieldBit)

Marks a field as being moved out.

pub const fn is_moved_out(&self, bit: FieldBit) -> bool

Checks whether a field has been moved out.

Trait Implementations

impl Clone for MovedOutFields

fn clone(&self) -> MovedOutFields

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for MovedOutFields

impl Debug for MovedOutFields

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.