protobuf/
ext.rs

1//! Utilities to support "extension" fields.
2//!
3//! This is a stopgap implementation, it only allows to fetch basic singular values,
4//! and that's it. Anything similar to extension registry is not implemented yet.
5//!
6//! Extensions are [described in the official protobuf documentation][exts].
7//!
8//! [exts]: https://developers.google.com/protocol-buffers/docs/proto#extensions
9
10use std::marker::PhantomData;
11
12use crate::descriptor::field_descriptor_proto::Type;
13use crate::reflect::runtime_types::RuntimeTypeTrait;
14use crate::reflect::ProtobufValue;
15use crate::Message;
16
17/// Optional ext field
18///
19/// This is initialized from generated code, do not instantiate directly.
20pub struct ExtFieldOptional<M, T> {
21    /// Extension field number.
22    field_number: u32,
23    /// Extension field type.
24    field_type: Type,
25    /// Marker
26    phantom: PhantomData<(M, T)>,
27}
28
29/// Repeated ext field
30///
31/// This is initialized from generated code, do not instantiate directly.
32pub struct ExtFieldRepeated<M, V> {
33    /// Extension field number
34    #[allow(dead_code)]
35    field_number: u32,
36    /// Field type.
37    #[allow(dead_code)]
38    field_type: Type,
39    /// Extension field number
40    phantom: PhantomData<(M, V)>,
41}
42
43impl<M, V> ExtFieldOptional<M, V> {
44    /// Constructor. Called from generated code.
45    pub const fn new(field_number: u32, field_type: Type) -> Self {
46        ExtFieldOptional {
47            field_number,
48            field_type,
49            phantom: PhantomData,
50        }
51    }
52}
53
54impl<M: Message, V: ProtobufValue> ExtFieldOptional<M, V> {
55    /// Get a copy of value from a message.
56    ///
57    /// Extension data is stored in [`UnknownFields`](crate::UnknownFields).
58    pub fn get(&self, m: &M) -> Option<V> {
59        m.unknown_fields()
60            .get(self.field_number)
61            .and_then(|u| V::RuntimeType::get_from_unknown(u, self.field_type))
62    }
63}
64
65impl<M, V> ExtFieldRepeated<M, V> {
66    /// Constructor. Called from generated code.
67    pub const fn new(field_number: u32, field_type: Type) -> Self {
68        ExtFieldRepeated {
69            field_number,
70            field_type,
71            phantom: PhantomData,
72        }
73    }
74}
75
76impl<M: Message, V: ProtobufValue> ExtFieldRepeated<M, V> {
77    /// Get a copy of value from a message (**not implemented**).
78    pub fn get(&self, _m: &M) -> Vec<V> {
79        unimplemented!("extension fields implementation in rust-protobuf is stopgap")
80    }
81}
protobuf/ext.rs

protobuf/
ext.rs
