Struct Shape

#[non_exhaustive]
#[repr(C)]
pub struct Shape<'shape> {
    pub id: ConstTypeId,
    pub layout: ShapeLayout,
    pub vtable: &'shape ValueVTable,
    pub ty: Type<'shape>,
    pub def: Def<'shape>,
    pub type_identifier: &'shape str,
    pub type_params: &'shape [TypeParam<'shape>],
    pub doc: &'shape [&'shape str],
    pub attributes: &'shape [ShapeAttribute<'shape>],
    pub type_tag: Option<&'shape str>,
    pub inner: Option<fn() -> &'shape Shape<'shape>>,
}

Schema for reflection of a type

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

id: ConstTypeId

Unique type identifier, provided by the compiler.

layout: ShapeLayout

Size, alignment — enough to allocate a value of this type (but not initialize it.)

vtable: &'shape ValueVTable

Function pointers to perform various operations: print the full type name (with generic type parameters), use the Display implementation, the Debug implementation, build a default value, clone, etc.

If the shape has ShapeLayout::Unsized, then the parent pointer needs to be passed.

There are more specific vtables in variants of Def

ty: Type<'shape>

Underlying type: primitive, sequence, user, pointer.

This follows the Rust Reference, but omits function types, and trait types, as they cannot be represented here.

def: Def<'shape>

Functional definition of the value: details for scalars, functions for inserting values into a map, or fetching a value from a list.

type_identifier: &'shape str

Identifier for a type: the type’s name without generic parameters. To get the type’s full name with generic parameters, see ValueVTable::type_name.

type_params: &'shape [TypeParam<'shape>]

Generic parameters for the shape

doc: &'shape [&'shape str]

Doc comment lines, collected by facet-derive. Note that they tend to start with a space.

attributes: &'shape [ShapeAttribute<'shape>]

Attributes that can be applied to a shape

type_tag: Option<&'shape str>

Shape type tag, used to identify the type in self describing formats.

For some formats, this is a fully or partially qualified name. For other formats, this is a simple string or integer type.

inner: Option<fn() -> &'shape Shape<'shape>>

As far as serialization and deserialization goes, we consider that this shape is a wrapper for that shape This is true for “newtypes” like NonZero, wrappers like Utf8PathBuf, smart pointers like Arc<T>, etc.

When this is set, deserialization takes that into account. For example, facet-json doesn’t expect:

{ “NonZero”: { “value”: 128 } }

It expects just

128

Same for Utf8PathBuf, which is parsed from and serialized to “just a string”.

See Wip’s innermost_shape function (and its support in put).

Implementations

impl<'shape> Shape<'shape>

pub fn is(&self, characteristic: Characteristic) -> bool

Checks if a shape has the given characteristic.

pub fn is_send(&self) -> bool

Check if this shape implements the Send trait

pub fn is_sync(&self) -> bool

Check if this shape implements the Sync trait

pub fn is_copy(&self) -> bool

Check if this shape implements the Copy trait

pub fn is_eq(&self) -> bool

Check if this shape implements the Eq trait

pub fn is_clone(&self) -> bool

Check if this shape implements the Clone trait

pub fn is_display(&self) -> bool

Check if this shape implements the Display trait

pub fn is_debug(&self) -> bool

Check if this shape implements the Debug trait

pub fn is_partial_eq(&self) -> bool

Check if this shape implements the PartialEq trait

pub fn is_partial_ord(&self) -> bool

Check if this shape implements the PartialOrd trait

pub fn is_ord(&self) -> bool

Check if this shape implements the Ord trait

pub fn is_hash(&self) -> bool

Check if this shape implements the Hash trait

pub fn is_default(&self) -> bool

Check if this shape implements the Default trait

pub fn is_from_str(&self) -> bool

Check if this shape implements the FromStr trait

pub fn write_type_name( &self, f: &mut Formatter<'_>, opts: TypeNameOpts, ) -> Result<(), Error>

Writes the name of this type to the given formatter

impl<'shape> Shape<'shape>

pub const fn builder_for_sized<'a, T>() -> ShapeBuilder<'shape>

where T: Facet<'a>,

Returns a builder for a shape for some type T.

pub const fn builder_for_unsized<'a, T>() -> ShapeBuilder<'shape>

where T: Facet<'a> + ?Sized,

Returns a builder for a shape for some type T.

pub fn is_type<Other>(&self) -> bool

where Other: Facet<'shape>,

Check if this shape is of the given type

pub fn assert_type<Other>(&self)

where Other: Facet<'shape>,

Assert that this shape is of the given type, panicking if it’s not

pub fn has_deny_unknown_fields_attr(&self) -> bool

See ShapeAttribute::DenyUnknownFields

pub fn has_default_attr(&self) -> bool

See ShapeAttribute::Default

pub fn get_rename_all_attr(&self) -> Option<&str>

See ShapeAttribute::RenameAll

impl Shape<'_>

pub fn is_shape(&self, other: &Shape<'_>) -> bool

Check if this shape is of the given type

pub fn assert_shape(&self, other: &Shape<'_>)

Assert that this shape is equal to the given shape, panicking if it’s not

impl Shape<'_>

pub fn allocate(&self) -> Result<PtrUninit<'static>, UnsizedError>

Heap-allocate a value of this shape

pub unsafe fn deallocate_mut(&self, ptr: PtrMut<'_>) -> Result<(), UnsizedError>

Deallocate a heap-allocated value of this shape

Safety

• ptr must have been allocated using Self::allocate and be aligned for this shape.
• ptr must point to a region that is not already deallocated.

pub unsafe fn deallocate_uninit( &self, ptr: PtrUninit<'static>, ) -> Result<(), UnsizedError>

Deallocate a heap-allocated, uninitialized value of this shape.

Safety

• ptr must have been allocated using Self::allocate (or equivalent) for this shape.
• ptr must not have been already deallocated.
• ptr must be properly aligned for this shape.

Trait Implementations

impl<'shape> Clone for Shape<'shape>

fn clone(&self) -> Shape<'shape>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Shape<'_>

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

Formats the value using the given formatter.

impl Display for Shape<'_>

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

Formats the value using the given formatter.

impl Hash for Shape<'_>

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

where H: Hasher,

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 PartialEq for Shape<'_>

fn eq(&self, other: &Shape<'_>) -> 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<'shape> Copy for Shape<'shape>

impl Eq for Shape<'_>