Struct glib::value::Value

#[repr(transparent)]
pub struct Value { /* private fields */ }

A generic value capable of carrying various types.

Once created the type of the value can’t be changed.

Some types (e.g. String and objects) support None values while others (e.g. numeric types) don’t.

Value does not implement the Send trait, but SendValue can be used instead.

See the module documentation for more details. An opaque structure used to hold different types of values.

The data within the structure has protected scope: it is accessible only to functions within a GTypeValueTable structure, or implementations of the g_value_*() API. That is, code portions which implement new fundamental types.

Value users cannot make any assumptions about how data is stored within the 2 element data union, and the g_type member should only be accessed through the G_VALUE_TYPE() macro.

Implementations

impl Value

pub fn as_ptr(&self) -> *mut GValue

impl Value

pub fn from_type(type_: Type) -> Self

Creates a new Value that is initialized with type_

pub fn for_value_type<T: ValueType>() -> Self

Creates a new Value that is initialized for a given ValueType.

pub fn get<'a, T>( &'a self ) -> Result<T, <<T as FromValue<'_>>::Checker as ValueTypeChecker>::Error>where T: FromValue<'a>,

Tries to get a value of type T.

Returns Ok if the type is correct.

pub fn get_owned<T>( &self ) -> Result<T, <<T as FromValue<'_>>::Checker as ValueTypeChecker>::Error>where T: for<'b> FromValue<'b> + 'static,

Tries to get a value of an owned type T.

pub fn is<T: StaticType>(&self) -> bool

Returns true if the type of the value corresponds to T or is a sub-type of T.

pub fn is_type(&self, type_: Type) -> bool

Returns true if the type of the value corresponds to type_ or is a sub-type of type_.

pub fn type_(&self) -> Type

Returns the type of the value.

pub fn type_transformable(src: Type, dst: Type) -> bool

Returns whether Values of type src can be transformed to type dst. Check whether transform() is able to transform values of type src_type into values of type dest_type. Note that for the types to be transformable, they must be compatible or a transformation function must be registered.

src_type

Source type.

dest_type

Target type.

Returns

true if the transformation is possible, false otherwise. 1].

Returns

a random number

pub fn transform<T: ValueType>(&self) -> Result<Value, BoolError>

Tries to transform the value into a value of the target type Tries to cast the contents of self into a type appropriate to store in dest_value, e.g. to transform a G_TYPE_INT value into a G_TYPE_FLOAT value. Performing transformations between value types might incur precision lossage. Especially transformations into strings might reveal seemingly arbitrary results and shouldn’t be relied upon for production code (such as rcfile value or object property serialization).

dest_value

Target value.

Returns

Whether a transformation rule was found and could be applied. Upon failing transformations, dest_value is left untouched.

pub fn transform_with_type(&self, type_: Type) -> Result<Value, BoolError>

Tries to transform the value into a value of the target type

pub fn into_raw(self) -> GValue

Consumes Value and returns the corresponding GValue.

pub fn try_into_send_value<T: Send + StaticType>( self ) -> Result<SendValue, Self>

Trait Implementations

impl Clone for Value

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Value

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

Formats the value using the given formatter.

impl Drop for Value

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, T: ?Sized + ToValue> From<&'a T> for Value

fn from(value: &'a T) -> Self

Converts to this type from the input type.

impl From<SendValue> for Value

fn from(value: SendValue) -> Self

Converts to this type from the input type.

impl<'a> FromValue<'a> for &'a Value

type Checker = NopChecker

Value type checker.

unsafe fn from_value(value: &'a Value) -> Self

Get the contained value from a Value.

impl<'a> FromValue<'a> for Value

type Checker = NopChecker

Value type checker.

unsafe fn from_value(value: &'a Value) -> Self

Get the contained value from a Value.

impl<'a> ToValue for &'a Value

fn to_value(&self) -> Value

Convert a value to a Value.

fn value_type(&self) -> Type

Returns the type identifer of self.

impl ToValue for Value

fn to_value(&self) -> Value

Convert a value to a Value.

fn value_type(&self) -> Type

Returns the type identifer of self.