| //! Support code for encoding and decoding types. |
| |
| /* |
| Core encoding and decoding interfaces. |
| */ |
| |
| use std::borrow::Cow; |
| use std::intrinsics; |
| use std::marker::PhantomData; |
| use std::path; |
| use std::rc::Rc; |
| use std::cell::{Cell, RefCell}; |
| use std::sync::Arc; |
| |
| pub trait Encoder { |
| type Error; |
| |
| // Primitive types: |
| fn emit_unit(&mut self) -> Result<(), Self::Error>; |
| fn emit_usize(&mut self, v: usize) -> Result<(), Self::Error>; |
| fn emit_u128(&mut self, v: u128) -> Result<(), Self::Error>; |
| fn emit_u64(&mut self, v: u64) -> Result<(), Self::Error>; |
| fn emit_u32(&mut self, v: u32) -> Result<(), Self::Error>; |
| fn emit_u16(&mut self, v: u16) -> Result<(), Self::Error>; |
| fn emit_u8(&mut self, v: u8) -> Result<(), Self::Error>; |
| fn emit_isize(&mut self, v: isize) -> Result<(), Self::Error>; |
| fn emit_i128(&mut self, v: i128) -> Result<(), Self::Error>; |
| fn emit_i64(&mut self, v: i64) -> Result<(), Self::Error>; |
| fn emit_i32(&mut self, v: i32) -> Result<(), Self::Error>; |
| fn emit_i16(&mut self, v: i16) -> Result<(), Self::Error>; |
| fn emit_i8(&mut self, v: i8) -> Result<(), Self::Error>; |
| fn emit_bool(&mut self, v: bool) -> Result<(), Self::Error>; |
| fn emit_f64(&mut self, v: f64) -> Result<(), Self::Error>; |
| fn emit_f32(&mut self, v: f32) -> Result<(), Self::Error>; |
| fn emit_char(&mut self, v: char) -> Result<(), Self::Error>; |
| fn emit_str(&mut self, v: &str) -> Result<(), Self::Error>; |
| |
| // Compound types: |
| fn emit_enum<F>(&mut self, _name: &str, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_enum_variant<F>(&mut self, _v_name: &str, v_id: usize, _len: usize, f: F) |
| -> Result<(), Self::Error> where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_usize(v_id)?; |
| f(self) |
| } |
| |
| fn emit_enum_variant_arg<F>(&mut self, _a_idx: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_enum_struct_variant<F>(&mut self, v_name: &str, v_id: usize, len: usize, f: F) |
| -> Result<(), Self::Error> where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_enum_variant(v_name, v_id, len, f) |
| } |
| |
| fn emit_enum_struct_variant_field<F>(&mut self, _f_name: &str, f_idx: usize, f: F) |
| -> Result<(), Self::Error> where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_enum_variant_arg(f_idx, f) |
| } |
| |
| fn emit_struct<F>(&mut self, _name: &str, _len: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_struct_field<F>(&mut self, _f_name: &str, _f_idx: usize, f: F) |
| -> Result<(), Self::Error> where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_tuple<F>(&mut self, _len: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_tuple_arg<F>(&mut self, _idx: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_tuple_struct<F>(&mut self, _name: &str, len: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_tuple(len, f) |
| } |
| |
| fn emit_tuple_struct_arg<F>(&mut self, f_idx: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_tuple_arg(f_idx, f) |
| } |
| |
| // Specialized types: |
| fn emit_option<F>(&mut self, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_enum("Option", f) |
| } |
| |
| #[inline] |
| fn emit_option_none(&mut self) -> Result<(), Self::Error> { |
| self.emit_enum_variant("None", 0, 0, |_| Ok(())) |
| } |
| |
| fn emit_option_some<F>(&mut self, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_enum_variant("Some", 1, 1, f) |
| } |
| |
| fn emit_seq<F>(&mut self, len: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_usize(len)?; |
| f(self) |
| } |
| |
| fn emit_seq_elt<F>(&mut self, _idx: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_map<F>(&mut self, len: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| self.emit_usize(len)?; |
| f(self) |
| } |
| |
| fn emit_map_elt_key<F>(&mut self, _idx: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| |
| fn emit_map_elt_val<F>(&mut self, _idx: usize, f: F) -> Result<(), Self::Error> |
| where F: FnOnce(&mut Self) -> Result<(), Self::Error> |
| { |
| f(self) |
| } |
| } |
| |
| pub trait Decoder { |
| type Error; |
| |
| // Primitive types: |
| fn read_nil(&mut self) -> Result<(), Self::Error>; |
| fn read_usize(&mut self) -> Result<usize, Self::Error>; |
| fn read_u128(&mut self) -> Result<u128, Self::Error>; |
| fn read_u64(&mut self) -> Result<u64, Self::Error>; |
| fn read_u32(&mut self) -> Result<u32, Self::Error>; |
| fn read_u16(&mut self) -> Result<u16, Self::Error>; |
| fn read_u8(&mut self) -> Result<u8, Self::Error>; |
| fn read_isize(&mut self) -> Result<isize, Self::Error>; |
| fn read_i128(&mut self) -> Result<i128, Self::Error>; |
| fn read_i64(&mut self) -> Result<i64, Self::Error>; |
| fn read_i32(&mut self) -> Result<i32, Self::Error>; |
| fn read_i16(&mut self) -> Result<i16, Self::Error>; |
| fn read_i8(&mut self) -> Result<i8, Self::Error>; |
| fn read_bool(&mut self) -> Result<bool, Self::Error>; |
| fn read_f64(&mut self) -> Result<f64, Self::Error>; |
| fn read_f32(&mut self) -> Result<f32, Self::Error>; |
| fn read_char(&mut self) -> Result<char, Self::Error>; |
| fn read_str(&mut self) -> Result<Cow<'_, str>, Self::Error>; |
| |
| // Compound types: |
| fn read_enum<T, F>(&mut self, _name: &str, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_enum_variant<T, F>(&mut self, _names: &[&str], mut f: F) -> Result<T, Self::Error> |
| where F: FnMut(&mut Self, usize) -> Result<T, Self::Error> |
| { |
| let disr = self.read_usize()?; |
| f(self, disr) |
| } |
| |
| fn read_enum_variant_arg<T, F>(&mut self, _a_idx: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_enum_struct_variant<T, F>(&mut self, names: &[&str], f: F) -> Result<T, Self::Error> |
| where F: FnMut(&mut Self, usize) -> Result<T, Self::Error> |
| { |
| self.read_enum_variant(names, f) |
| } |
| |
| fn read_enum_struct_variant_field<T, F>(&mut self, _f_name: &str, f_idx: usize, f: F) |
| -> Result<T, Self::Error> where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| self.read_enum_variant_arg(f_idx, f) |
| } |
| |
| fn read_struct<T, F>(&mut self, _s_name: &str, _len: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_struct_field<T, F>(&mut self, _f_name: &str, _f_idx: usize, f: F) |
| -> Result<T, Self::Error> where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_tuple<T, F>(&mut self, _len: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_tuple_arg<T, F>(&mut self, _a_idx: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_tuple_struct<T, F>(&mut self, _s_name: &str, len: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| self.read_tuple(len, f) |
| } |
| |
| fn read_tuple_struct_arg<T, F>(&mut self, a_idx: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| self.read_tuple_arg(a_idx, f) |
| } |
| |
| // Specialized types: |
| fn read_option<T, F>(&mut self, mut f: F) -> Result<T, Self::Error> |
| where F: FnMut(&mut Self, bool) -> Result<T, Self::Error> |
| { |
| self.read_enum("Option", move |this| { |
| this.read_enum_variant(&["None", "Some"], move |this, idx| { |
| match idx { |
| 0 => f(this, false), |
| 1 => f(this, true), |
| _ => Err(this.error("read_option: expected 0 for None or 1 for Some")), |
| } |
| }) |
| }) |
| } |
| |
| fn read_seq<T, F>(&mut self, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self, usize) -> Result<T, Self::Error> |
| { |
| let len = self.read_usize()?; |
| f(self, len) |
| } |
| |
| fn read_seq_elt<T, F>(&mut self, _idx: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_map<T, F>(&mut self, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self, usize) -> Result<T, Self::Error> |
| { |
| let len = self.read_usize()?; |
| f(self, len) |
| } |
| |
| fn read_map_elt_key<T, F>(&mut self, _idx: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| fn read_map_elt_val<T, F>(&mut self, _idx: usize, f: F) -> Result<T, Self::Error> |
| where F: FnOnce(&mut Self) -> Result<T, Self::Error> |
| { |
| f(self) |
| } |
| |
| // Failure |
| fn error(&mut self, err: &str) -> Self::Error; |
| } |
| |
| pub trait Encodable { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error>; |
| } |
| |
| pub trait Decodable: Sized { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error>; |
| } |
| |
| impl Encodable for usize { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_usize(*self) |
| } |
| } |
| |
| impl Decodable for usize { |
| fn decode<D: Decoder>(d: &mut D) -> Result<usize, D::Error> { |
| d.read_usize() |
| } |
| } |
| |
| impl Encodable for u8 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_u8(*self) |
| } |
| } |
| |
| impl Decodable for u8 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<u8, D::Error> { |
| d.read_u8() |
| } |
| } |
| |
| impl Encodable for u16 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_u16(*self) |
| } |
| } |
| |
| impl Decodable for u16 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<u16, D::Error> { |
| d.read_u16() |
| } |
| } |
| |
| impl Encodable for u32 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_u32(*self) |
| } |
| } |
| |
| impl Decodable for u32 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<u32, D::Error> { |
| d.read_u32() |
| } |
| } |
| |
| impl Encodable for ::std::num::NonZeroU32 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_u32(self.get()) |
| } |
| } |
| |
| impl Decodable for ::std::num::NonZeroU32 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error> { |
| d.read_u32().map(|d| ::std::num::NonZeroU32::new(d).unwrap()) |
| } |
| } |
| |
| impl Encodable for u64 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_u64(*self) |
| } |
| } |
| |
| impl Decodable for u64 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<u64, D::Error> { |
| d.read_u64() |
| } |
| } |
| |
| impl Encodable for u128 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_u128(*self) |
| } |
| } |
| |
| impl Decodable for u128 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<u128, D::Error> { |
| d.read_u128() |
| } |
| } |
| |
| impl Encodable for isize { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_isize(*self) |
| } |
| } |
| |
| impl Decodable for isize { |
| fn decode<D: Decoder>(d: &mut D) -> Result<isize, D::Error> { |
| d.read_isize() |
| } |
| } |
| |
| impl Encodable for i8 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_i8(*self) |
| } |
| } |
| |
| impl Decodable for i8 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<i8, D::Error> { |
| d.read_i8() |
| } |
| } |
| |
| impl Encodable for i16 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_i16(*self) |
| } |
| } |
| |
| impl Decodable for i16 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<i16, D::Error> { |
| d.read_i16() |
| } |
| } |
| |
| impl Encodable for i32 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_i32(*self) |
| } |
| } |
| |
| impl Decodable for i32 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<i32, D::Error> { |
| d.read_i32() |
| } |
| } |
| |
| impl Encodable for i64 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_i64(*self) |
| } |
| } |
| |
| impl Decodable for i64 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<i64, D::Error> { |
| d.read_i64() |
| } |
| } |
| |
| impl Encodable for i128 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_i128(*self) |
| } |
| } |
| |
| impl Decodable for i128 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<i128, D::Error> { |
| d.read_i128() |
| } |
| } |
| |
| impl Encodable for str { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_str(self) |
| } |
| } |
| |
| impl Encodable for String { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_str(&self[..]) |
| } |
| } |
| |
| impl Decodable for String { |
| fn decode<D: Decoder>(d: &mut D) -> Result<String, D::Error> { |
| Ok(d.read_str()?.into_owned()) |
| } |
| } |
| |
| impl Encodable for f32 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_f32(*self) |
| } |
| } |
| |
| impl Decodable for f32 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<f32, D::Error> { |
| d.read_f32() |
| } |
| } |
| |
| impl Encodable for f64 { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_f64(*self) |
| } |
| } |
| |
| impl Decodable for f64 { |
| fn decode<D: Decoder>(d: &mut D) -> Result<f64, D::Error> { |
| d.read_f64() |
| } |
| } |
| |
| impl Encodable for bool { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_bool(*self) |
| } |
| } |
| |
| impl Decodable for bool { |
| fn decode<D: Decoder>(d: &mut D) -> Result<bool, D::Error> { |
| d.read_bool() |
| } |
| } |
| |
| impl Encodable for char { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_char(*self) |
| } |
| } |
| |
| impl Decodable for char { |
| fn decode<D: Decoder>(d: &mut D) -> Result<char, D::Error> { |
| d.read_char() |
| } |
| } |
| |
| impl Encodable for () { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_unit() |
| } |
| } |
| |
| impl Decodable for () { |
| fn decode<D: Decoder>(d: &mut D) -> Result<(), D::Error> { |
| d.read_nil() |
| } |
| } |
| |
| impl<T> Encodable for PhantomData<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_unit() |
| } |
| } |
| |
| impl<T> Decodable for PhantomData<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<PhantomData<T>, D::Error> { |
| d.read_nil()?; |
| Ok(PhantomData) |
| } |
| } |
| |
| impl<'a, T: ?Sized + Encodable> Encodable for &'a T { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| (**self).encode(s) |
| } |
| } |
| |
| impl<T: ?Sized + Encodable> Encodable for Box<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| (**self).encode(s) |
| } |
| } |
| |
| impl< T: Decodable> Decodable for Box<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Box<T>, D::Error> { |
| Ok(box Decodable::decode(d)?) |
| } |
| } |
| |
| impl< T: Decodable> Decodable for Box<[T]> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Box<[T]>, D::Error> { |
| let v: Vec<T> = Decodable::decode(d)?; |
| Ok(v.into_boxed_slice()) |
| } |
| } |
| |
| impl<T:Encodable> Encodable for Rc<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| (**self).encode(s) |
| } |
| } |
| |
| impl<T:Decodable> Decodable for Rc<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Rc<T>, D::Error> { |
| Ok(Rc::new(Decodable::decode(d)?)) |
| } |
| } |
| |
| impl<T:Encodable> Encodable for [T] { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_seq(self.len(), |s| { |
| for (i, e) in self.iter().enumerate() { |
| s.emit_seq_elt(i, |s| e.encode(s))? |
| } |
| Ok(()) |
| }) |
| } |
| } |
| |
| impl<T:Encodable> Encodable for Vec<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_seq(self.len(), |s| { |
| for (i, e) in self.iter().enumerate() { |
| s.emit_seq_elt(i, |s| e.encode(s))? |
| } |
| Ok(()) |
| }) |
| } |
| } |
| |
| impl<T:Decodable> Decodable for Vec<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Vec<T>, D::Error> { |
| d.read_seq(|d, len| { |
| let mut v = Vec::with_capacity(len); |
| for i in 0..len { |
| v.push(d.read_seq_elt(i, |d| Decodable::decode(d))?); |
| } |
| Ok(v) |
| }) |
| } |
| } |
| |
| impl<'a, T:Encodable> Encodable for Cow<'a, [T]> where [T]: ToOwned<Owned = Vec<T>> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_seq(self.len(), |s| { |
| for (i, e) in self.iter().enumerate() { |
| s.emit_seq_elt(i, |s| e.encode(s))? |
| } |
| Ok(()) |
| }) |
| } |
| } |
| |
| impl<T:Decodable+ToOwned> Decodable for Cow<'static, [T]> |
| where [T]: ToOwned<Owned = Vec<T>> |
| { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Cow<'static, [T]>, D::Error> { |
| d.read_seq(|d, len| { |
| let mut v = Vec::with_capacity(len); |
| for i in 0..len { |
| v.push(d.read_seq_elt(i, |d| Decodable::decode(d))?); |
| } |
| Ok(Cow::Owned(v)) |
| }) |
| } |
| } |
| |
| |
| impl<T:Encodable> Encodable for Option<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_option(|s| { |
| match *self { |
| None => s.emit_option_none(), |
| Some(ref v) => s.emit_option_some(|s| v.encode(s)), |
| } |
| }) |
| } |
| } |
| |
| impl<T:Decodable> Decodable for Option<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Option<T>, D::Error> { |
| d.read_option(|d, b| { |
| if b { |
| Ok(Some(Decodable::decode(d)?)) |
| } else { |
| Ok(None) |
| } |
| }) |
| } |
| } |
| |
| impl<T1: Encodable, T2: Encodable> Encodable for Result<T1, T2> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| s.emit_enum("Result", |s| { |
| match *self { |
| Ok(ref v) => { |
| s.emit_enum_variant("Ok", 0, 1, |s| { |
| s.emit_enum_variant_arg(0, |s| { |
| v.encode(s) |
| }) |
| }) |
| } |
| Err(ref v) => { |
| s.emit_enum_variant("Err", 1, 1, |s| { |
| s.emit_enum_variant_arg(0, |s| { |
| v.encode(s) |
| }) |
| }) |
| } |
| } |
| }) |
| } |
| } |
| |
| impl<T1:Decodable, T2:Decodable> Decodable for Result<T1, T2> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Result<T1, T2>, D::Error> { |
| d.read_enum("Result", |d| { |
| d.read_enum_variant(&["Ok", "Err"], |d, disr| { |
| match disr { |
| 0 => { |
| Ok(Ok(d.read_enum_variant_arg(0, |d| { |
| T1::decode(d) |
| })?)) |
| } |
| 1 => { |
| Ok(Err(d.read_enum_variant_arg(0, |d| { |
| T2::decode(d) |
| })?)) |
| } |
| _ => { |
| panic!("Encountered invalid discriminant while \ |
| decoding `Result`."); |
| } |
| } |
| }) |
| }) |
| } |
| } |
| |
| macro_rules! peel { |
| ($name:ident, $($other:ident,)*) => (tuple! { $($other,)* }) |
| } |
| |
| /// Evaluates to the number of tokens passed to it. |
| /// |
| /// Logarithmic counting: every one or two recursive expansions, the number of |
| /// tokens to count is divided by two, instead of being reduced by one. |
| /// Therefore, the recursion depth is the binary logarithm of the number of |
| /// tokens to count, and the expanded tree is likewise very small. |
| macro_rules! count { |
| () => (0usize); |
| ($one:tt) => (1usize); |
| ($($pairs:tt $_p:tt)*) => (count!($($pairs)*) << 1usize); |
| ($odd:tt $($rest:tt)*) => (count!($($rest)*) | 1usize); |
| } |
| |
| macro_rules! tuple { |
| () => (); |
| ( $($name:ident,)+ ) => ( |
| impl<$($name:Decodable),*> Decodable for ($($name,)*) { |
| #[allow(non_snake_case)] |
| fn decode<D: Decoder>(d: &mut D) -> Result<($($name,)*), D::Error> { |
| let len: usize = count!($($name)*); |
| d.read_tuple(len, |d| { |
| let mut i = 0; |
| let ret = ($(d.read_tuple_arg({ i+=1; i-1 }, |d| -> Result<$name, D::Error> { |
| Decodable::decode(d) |
| })?,)*); |
| Ok(ret) |
| }) |
| } |
| } |
| impl<$($name:Encodable),*> Encodable for ($($name,)*) { |
| #[allow(non_snake_case)] |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| let ($(ref $name,)*) = *self; |
| let mut n = 0; |
| $(let $name = $name; n += 1;)* |
| s.emit_tuple(n, |s| { |
| let mut i = 0; |
| $(s.emit_tuple_arg({ i+=1; i-1 }, |s| $name.encode(s))?;)* |
| Ok(()) |
| }) |
| } |
| } |
| peel! { $($name,)* } |
| ) |
| } |
| |
| tuple! { T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, } |
| |
| impl Encodable for path::Path { |
| fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> { |
| self.to_str().unwrap().encode(e) |
| } |
| } |
| |
| impl Encodable for path::PathBuf { |
| fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> { |
| path::Path::encode(self, e) |
| } |
| } |
| |
| impl Decodable for path::PathBuf { |
| fn decode<D: Decoder>(d: &mut D) -> Result<path::PathBuf, D::Error> { |
| let bytes: String = Decodable::decode(d)?; |
| Ok(path::PathBuf::from(bytes)) |
| } |
| } |
| |
| impl<T: Encodable + Copy> Encodable for Cell<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| self.get().encode(s) |
| } |
| } |
| |
| impl<T: Decodable + Copy> Decodable for Cell<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Cell<T>, D::Error> { |
| Ok(Cell::new(Decodable::decode(d)?)) |
| } |
| } |
| |
| // FIXME: #15036 |
| // Should use `try_borrow`, returning a |
| // `encoder.error("attempting to Encode borrowed RefCell")` |
| // from `encode` when `try_borrow` returns `None`. |
| |
| impl<T: Encodable> Encodable for RefCell<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| self.borrow().encode(s) |
| } |
| } |
| |
| impl<T: Decodable> Decodable for RefCell<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<RefCell<T>, D::Error> { |
| Ok(RefCell::new(Decodable::decode(d)?)) |
| } |
| } |
| |
| impl<T:Encodable> Encodable for Arc<T> { |
| fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> { |
| (**self).encode(s) |
| } |
| } |
| |
| impl<T:Decodable> Decodable for Arc<T> { |
| fn decode<D: Decoder>(d: &mut D) -> Result<Arc<T>, D::Error> { |
| Ok(Arc::new(Decodable::decode(d)?)) |
| } |
| } |
| |
| // ___________________________________________________________________________ |
| // Specialization-based interface for multi-dispatch Encodable/Decodable. |
| |
| /// Implement this trait on your `{Encodable,Decodable}::Error` types |
| /// to override the default panic behavior for missing specializations. |
| pub trait SpecializationError { |
| /// Creates an error for a missing method specialization. |
| /// Defaults to panicking with type, trait & method names. |
| /// `S` is the encoder/decoder state type, |
| /// `T` is the type being encoded/decoded, and |
| /// the arguments are the names of the trait |
| /// and method that should've been overridden. |
| fn not_found<S, T: ?Sized>(trait_name: &'static str, method_name: &'static str) -> Self; |
| } |
| |
| impl<E> SpecializationError for E { |
| default fn not_found<S, T: ?Sized>(trait_name: &'static str, method_name: &'static str) -> E { |
| panic!("missing specialization: `<{} as {}<{}>>::{}` not overridden", |
| unsafe { intrinsics::type_name::<S>() }, |
| trait_name, |
| unsafe { intrinsics::type_name::<T>() }, |
| method_name); |
| } |
| } |
| |
| /// Implement this trait on encoders, with `T` being the type |
| /// you want to encode (employing `UseSpecializedEncodable`), |
| /// using a strategy specific to the encoder. |
| pub trait SpecializedEncoder<T: ?Sized + UseSpecializedEncodable>: Encoder { |
| /// Encode the value in a manner specific to this encoder state. |
| fn specialized_encode(&mut self, value: &T) -> Result<(), Self::Error>; |
| } |
| |
| impl<E: Encoder, T: ?Sized + UseSpecializedEncodable> SpecializedEncoder<T> for E { |
| default fn specialized_encode(&mut self, value: &T) -> Result<(), E::Error> { |
| value.default_encode(self) |
| } |
| } |
| |
| /// Implement this trait on decoders, with `T` being the type |
| /// you want to decode (employing `UseSpecializedDecodable`), |
| /// using a strategy specific to the decoder. |
| pub trait SpecializedDecoder<T: UseSpecializedDecodable>: Decoder { |
| /// Decode a value in a manner specific to this decoder state. |
| fn specialized_decode(&mut self) -> Result<T, Self::Error>; |
| } |
| |
| impl<D: Decoder, T: UseSpecializedDecodable> SpecializedDecoder<T> for D { |
| default fn specialized_decode(&mut self) -> Result<T, D::Error> { |
| T::default_decode(self) |
| } |
| } |
| |
| /// Implement this trait on your type to get an `Encodable` |
| /// implementation which goes through `SpecializedEncoder`. |
| pub trait UseSpecializedEncodable { |
| /// Defaults to returning an error (see `SpecializationError`). |
| fn default_encode<E: Encoder>(&self, _: &mut E) -> Result<(), E::Error> { |
| Err(E::Error::not_found::<E, Self>("SpecializedEncoder", "specialized_encode")) |
| } |
| } |
| |
| impl<T: ?Sized + UseSpecializedEncodable> Encodable for T { |
| default fn encode<E: Encoder>(&self, e: &mut E) -> Result<(), E::Error> { |
| E::specialized_encode(e, self) |
| } |
| } |
| |
| /// Implement this trait on your type to get an `Decodable` |
| /// implementation which goes through `SpecializedDecoder`. |
| pub trait UseSpecializedDecodable: Sized { |
| /// Defaults to returning an error (see `SpecializationError`). |
| fn default_decode<D: Decoder>(_: &mut D) -> Result<Self, D::Error> { |
| Err(D::Error::not_found::<D, Self>("SpecializedDecoder", "specialized_decode")) |
| } |
| } |
| |
| impl<T: UseSpecializedDecodable> Decodable for T { |
| default fn decode<D: Decoder>(d: &mut D) -> Result<T, D::Error> { |
| D::specialized_decode(d) |
| } |
| } |
| |
| // Can't avoid specialization for &T and Box<T> impls, |
| // as proxy impls on them are blankets that conflict |
| // with the Encodable and Decodable impls above, |
| // which only have `default` on their methods |
| // for this exact reason. |
| // May be fixable in a simpler fashion via the |
| // more complex lattice model for specialization. |
| impl<'a, T: ?Sized + Encodable> UseSpecializedEncodable for &'a T {} |
| impl<T: ?Sized + Encodable> UseSpecializedEncodable for Box<T> {} |
| impl<T: Decodable> UseSpecializedDecodable for Box<T> {} |
| impl<'a, T: Decodable> UseSpecializedDecodable for &'a T {} |
| impl<'a, T: Decodable> UseSpecializedDecodable for &'a [T] {} |