src/vendor/serde/src/de/private.rs

   1 use core::marker::PhantomData;
   2
   3 use de::{Deserialize, Deserializer, Error, Visitor};
   4
   5 #[cfg(any(feature = "std", feature = "collections"))]
   6 pub use de::content::{Content, ContentRefDeserializer, ContentDeserializer, TaggedContentVisitor,
   7                       TagOrContentField, TagOrContentFieldVisitor, InternallyTaggedUnitVisitor,
   8                       UntaggedUnitVisitor};
   9
  10 /// If the missing field is of type `Option<T>` then treat is as `None`,
  11 /// otherwise it is an error.
  12 pub fn missing_field<V, E>(field: &'static str) -> Result<V, E>
  13     where V: Deserialize,
  14           E: Error
  15 {
  16     struct MissingFieldDeserializer<E>(&'static str, PhantomData<E>);
  17
  18     impl<E> Deserializer for MissingFieldDeserializer<E>
  19         where E: Error
  20     {
  21         type Error = E;
  22
  23         fn deserialize<V>(self, _visitor: V) -> Result<V::Value, E>
  24             where V: Visitor
  25         {
  26             Err(Error::missing_field(self.0))
  27         }
  28
  29         fn deserialize_option<V>(self, visitor: V) -> Result<V::Value, E>
  30             where V: Visitor
  31         {
  32             visitor.visit_none()
  33         }
  34
  35         forward_to_deserialize! {
  36             bool u8 u16 u32 u64 i8 i16 i32 i64 f32 f64 char str string unit seq
  37             seq_fixed_size bytes byte_buf map unit_struct newtype_struct
  38             tuple_struct struct struct_field tuple enum ignored_any
  39         }
  40     }
  41
  42     let deserializer = MissingFieldDeserializer(field, PhantomData);
  43     Deserialize::deserialize(deserializer)
  44 }