Enum PointerRepr 

#[non_exhaustive]
pub enum PointerRepr {
    Box,
    Inline,
    Custom(String),
}

The owned smart pointer a singular message field’s buffa::MessageField wraps in generated owned structs.

The default is Box. Custom substitutes any pointer that satisfies the buffa::ProtoBox<T> bound — for example a smallbox-style pointer that stores small messages inline. Because the pointer wraps the message type, its path is a template containing a * placeholder for the message type (e.g. "::smallbox::SmallBox<*, ::smallbox::space::S4>" or "::my_crate::SmallBox<*>").

Because buffa::ProtoBox is buffa-owned, a foreign pointer cannot implement it directly (orphan rule) — the template must name a crate-local newtype, mirroring the ProtoString newtype expectation.

Select a representation through buffa_build’s box_type_custom builder method. The wire format is identical regardless of the pointer; view types are unaffected. Applies to singular message fields and boxed oneof message/group variants (a variant opted into inline storage via unboxed_oneof_fields takes precedence and gets no pointer). Repeated message fields use a collection, not a pointer.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Box

::buffa::alloc::boxed::Box<T> (inside MessageField<T>). The opt-out from the Inline default for large or rarely-set submessages, via box_type_in(PointerRepr::Box, paths) (or box_type(PointerRepr::Box) to restore the pre-0.9 global default).

Inline

::buffa::Inline<T> — store the message directly in the parent struct, no heap allocation. MessageField<T, Inline<T>> is laid out as Option<T>. The default.

Recursion-aware: a singular field that would form an infinite-size cycle (directly, mutually, or via an unbox_oneof-inlined oneof variant) is silently kept on Box, so the default is always sized. An exact-path Inline rule that names a recursive field is rejected at codegen time.

Custom(String)

A custom pointer named by a Rust type-path template with a * placeholder for the message type. Must satisfy buffa::ProtoBox<T> and be a crate-local newtype.

Limitations

• The template must contain at least one *; a template that omits it surfaces as CodeGenError::MissingWildcard, and one whose substitution does not parse as CodeGenError::InvalidTypePath, at generation (.compile()) time.
• Rc / Arc and other shared/COW pointers are unusable: the decoder merges in place (needs DerefMut), so only an exclusively-owned pointer (heap Box, inline SmallBox) can implement ProtoBox.
• An inline pointer inflates the parent struct per field, so select it per field/prefix, never as a blanket default.
• On a boxed oneof variant under the arbitrary feature, the custom pointer must implement arbitrary::Arbitrary (the oneof enum derives it and stores the pointer directly in the variant). The singular-field path needs no such impl — MessageField constructs the pointer itself.

Trait Implementations

impl Clone for PointerRepr

fn clone(&self) -> PointerRepr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PointerRepr

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

Formats the value using the given formatter.

impl Default for PointerRepr

fn default() -> PointerRepr

Returns the “default value” for a type.

impl Eq for PointerRepr

impl PartialEq for PointerRepr

fn eq(&self, other: &PointerRepr) -> bool

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for PointerRepr