Struct MaybeNull 

pub struct MaybeNull<T: Nullable>(/* private fields */);

A wrapper that can be used as an Option<T> without requiring extra space to indicate whether the value is Some or None.

This can be used when a specific value of T indicates that its value is None.

Implementations

impl<T: Nullable> MaybeNull<T>

pub fn get(self) -> Option<T>

Returns the contained value as an Option.

pub fn as_ref(&self) -> Option<&T>

Returns a reference to the contained value as an Option.

pub fn as_mut(&mut self) -> Option<&mut T>

Returns a mutable reference to the contained value as an Option.

pub fn copied(&self) -> Option<T>

where T: Copy,

Maps a MaybeNull<T> to an Option<T> by copying the contents of the option.

pub fn cloned(&self) -> Option<T>

where T: Clone,

Maps a MaybeNull<T> to an Option<T> by cloning the contents of the option.

Trait Implementations

impl<T> BorshDeserialize for MaybeNull<T>

where T: BorshDeserialize + Nullable,

fn deserialize_reader<__R: Read>(reader: &mut __R) -> Result<Self, Error>

fn deserialize(buf: &mut &[u8]) -> Result<Self, Error>

Deserializes this instance from a given slice of bytes. Updates the buffer to point at the remaining bytes.

fn try_from_slice(v: &[u8]) -> Result<Self, Error>

Deserialize this instance from a slice of bytes.

fn try_from_reader<R>(reader: &mut R) -> Result<Self, Error>

where R: Read,

impl<T> BorshSchema for MaybeNull<T>

where T: BorshSchema + Nullable,

fn declaration() -> Declaration

Get the name of the type without brackets.

fn add_definitions_recursively( definitions: &mut BTreeMap<Declaration, Definition>, )

Recursively, using DFS, add type definitions required for this type. Type definition partially explains how to serialize/deserialize a type.

impl<T> BorshSerialize for MaybeNull<T>

where T: BorshSerialize + Nullable,

fn serialize<__W: Write>(&self, writer: &mut __W) -> Result<(), Error>

impl<T: Clone + Nullable> Clone for MaybeNull<T>

fn clone(&self) -> MaybeNull<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug + Nullable> Debug for MaybeNull<T>

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

Formats the value using the given formatter.

impl<T: Nullable> Default for MaybeNull<T>

fn default() -> Self

Returns the “default value” for a type.

impl<'de, T> Deserialize<'de> for MaybeNull<T>

where T: Nullable + Deserialize<'de>,

Available on crate feature serde only.

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<'de, T, U> DeserializeAs<'de, MaybeNull<T>> for Option<U>

where T: Nullable, U: DeserializeAs<'de, T>,

Available on crate feature serde-with only.

fn deserialize_as<D>(deserializer: D) -> Result<MaybeNull<T>, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T: Nullable> From<MaybeNull<T>> for Option<T>

fn from(value: MaybeNull<T>) -> Self

Converts to this type from the input type.

impl<T: Nullable> From<T> for MaybeNull<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T: Hash + Nullable> Hash for MaybeNull<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: PartialEq + Nullable> PartialEq for MaybeNull<T>

fn eq(&self, other: &MaybeNull<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'de, T, WincodeConfig: Config> SchemaRead<'de, WincodeConfig> for MaybeNull<T>

where T: SchemaRead<'de, WincodeConfig, Dst = T> + Nullable,

const TYPE_META: TypeMeta

Metadata about the type’s serialization.

type Dst = MaybeNull<T>

fn read( reader: impl Reader<'de>, dst: &mut MaybeUninit<Self::Dst>, ) -> ReadResult<()>

Read into dst from reader.

fn get(reader: impl Reader<'de>) -> Result<Self::Dst, ReadError>

Read Self::Dst from reader into a new Self::Dst.

impl<T, WincodeConfig: Config> SchemaWrite<WincodeConfig> for MaybeNull<T>

where T: SchemaWrite<WincodeConfig, Src = T> + Nullable,

const TYPE_META: TypeMeta

Metadata about the type’s serialization.

type Src = MaybeNull<T>

fn size_of(src: &Self::Src) -> WriteResult<usize>

Get the serialized size of Self::Src.

fn write(writer: impl Writer, src: &Self::Src) -> WriteResult<()>

Write Self::Src to writer.

impl<T> Serialize for MaybeNull<T>

where T: Nullable + Serialize,

Available on crate feature serde only.

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<T, U> SerializeAs<MaybeNull<T>> for Option<U>

where T: Nullable, U: SerializeAs<T>,

Available on crate feature serde-with only.

fn serialize_as<S>( source: &MaybeNull<T>, serializer: S, ) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl<T: Nullable> TryFrom<Option<T>> for MaybeNull<T>

type Error = MaybeNullError

The type returned in the event of a conversion error.

fn try_from(value: Option<T>) -> Result<Self, Self::Error>

Performs the conversion.

impl<T, C> ZeroCopy<C> for MaybeNull<T>

where C: ConfigCore, T: Nullable + ZeroCopy<C>,

Available on crate feature wincode only.

Safety

MaybeNull<T> where T: ZeroCopy is trivially zero-copy.

fn from_bytes<'de>(bytes: &'de [u8], config: C) -> Result<&'de Self, ReadError>

where Self: Sized + SchemaRead<'de, C, Dst = Self>,

Like crate::ZeroCopy::from_bytes, but allows the caller to provide a custom configuration.

fn from_bytes_mut<'de>( bytes: &'de mut [u8], config: C, ) -> Result<&'de mut Self, ReadError>

where Self: Sized + SchemaRead<'de, C, Dst = Self>,

Like crate::ZeroCopy::from_bytes_mut, but allows the caller to provide a custom configuration.

impl<T: Nullable + Zeroable> Zeroable for MaybeNull<T>

Available on crate feature bytemuck only.

Safety

MaybeNull is a transparent wrapper around a bytemuck Pod type T with identical data representation.

fn zeroed() -> Self

Calls zeroed.

impl<T: Copy + Nullable> Copy for MaybeNull<T>

impl<T: Eq + Nullable> Eq for MaybeNull<T>

impl<T: Nullable + Pod> Pod for MaybeNull<T>

Available on crate feature bytemuck only.

Safety

MaybeNull is a transparent wrapper around a bytemuck Pod type T with identical data representation.

impl<T: Nullable> StructuralPartialEq for MaybeNull<T>