Struct FieldDescriptor 

pub struct FieldDescriptor { /* private fields */ }

Handle to one field in a MessageDescriptor.

Implementations

impl FieldDescriptor

pub fn name(&self) -> &str

Proto field name.

pub fn full_name(&self) -> &str

<message.full_name>.<name>, no leading dot.

pub fn json_name(&self) -> &str

JSON field name (lower-camelCase by default; honors a user-supplied json_name option when present).

pub fn number(&self) -> u32

Tag number on the wire.

pub fn kind(&self) -> Kind

Resolved field Kind.

pub fn cardinality(&self) -> Cardinality

Optional, Required, or Repeated.

pub fn supports_presence(&self) -> bool

True iff the wire format tracks presence for this field (proto2 scalars, message-typed fields, oneof members, proto3 optional).

pub fn is_packed(&self) -> bool

True iff the field uses packed encoding for repeated scalars.

pub fn is_packable(&self) -> bool

True iff this field’s Kind admits packed encoding (scalar or enum) — independent of whether is_packed() is currently set.

pub fn is_list(&self) -> bool

True iff this is a repeated (non-map) field.

Note that map<K, V> fields are technically also repeated on the wire, but their value model is crate::Value::Map, not crate::Value::List — this helper returns false for maps.

pub fn parsed_default_value(&self) -> Option<Value>

Available on crate feature dynamic only.

Pre-parsed [default = ...] value, if the field carried one.

Available for any scalar / enum / string / bytes field whose proto declared an explicit default. None for proto3 fields, for repeated fields, and for fields without an explicit default.

pub fn is_map(&self) -> bool

True iff this field models a map<K, V>.

A field is a map iff its kind is a message that carries the map_entry = true option.

pub fn containing_oneof(&self) -> Option<OneofDescriptor>

Containing oneof, when this field is part of one.

pub fn parent_message(&self) -> MessageDescriptor

Owning message.

pub fn descriptor_proto(&self) -> &FieldDescriptorProto

Raw FieldDescriptorProto for advanced use.

Trait Implementations

impl Clone for FieldDescriptor

fn clone(&self) -> FieldDescriptor

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FieldDescriptor

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

Formats the value using the given formatter.

impl Eq for FieldDescriptor

impl PartialEq for FieldDescriptor

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

Equality operator ==.

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

Inequality operator !=.