1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Support code for encoding and decoding types.
14 Core encoding and decoding interfaces.
19 use std::cell::{Cell, RefCell};
26 fn emit_nil(&mut self) -> Result<(), Self::Error>;
27 fn emit_uint(&mut self, v: usize) -> Result<(), Self::Error>;
28 fn emit_u64(&mut self, v: u64) -> Result<(), Self::Error>;
29 fn emit_u32(&mut self, v: u32) -> Result<(), Self::Error>;
30 fn emit_u16(&mut self, v: u16) -> Result<(), Self::Error>;
31 fn emit_u8(&mut self, v: u8) -> Result<(), Self::Error>;
32 fn emit_int(&mut self, v: isize) -> Result<(), Self::Error>;
33 fn emit_i64(&mut self, v: i64) -> Result<(), Self::Error>;
34 fn emit_i32(&mut self, v: i32) -> Result<(), Self::Error>;
35 fn emit_i16(&mut self, v: i16) -> Result<(), Self::Error>;
36 fn emit_i8(&mut self, v: i8) -> Result<(), Self::Error>;
37 fn emit_bool(&mut self, v: bool) -> Result<(), Self::Error>;
38 fn emit_f64(&mut self, v: f64) -> Result<(), Self::Error>;
39 fn emit_f32(&mut self, v: f32) -> Result<(), Self::Error>;
40 fn emit_char(&mut self, v: char) -> Result<(), Self::Error>;
41 fn emit_str(&mut self, v: &str) -> Result<(), Self::Error>;
44 fn emit_enum<F>(&mut self, name: &str, f: F) -> Result<(), Self::Error>
45 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
47 fn emit_enum_variant<F>(&mut self, v_name: &str,
50 f: F) -> Result<(), Self::Error>
51 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
52 fn emit_enum_variant_arg<F>(&mut self, a_idx: usize, f: F)
53 -> Result<(), Self::Error>
54 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
56 fn emit_enum_struct_variant<F>(&mut self, v_name: &str,
59 f: F) -> Result<(), Self::Error>
60 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
61 fn emit_enum_struct_variant_field<F>(&mut self,
64 f: F) -> Result<(), Self::Error>
65 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
67 fn emit_struct<F>(&mut self, name: &str, len: usize, f: F)
68 -> Result<(), Self::Error>
69 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
70 fn emit_struct_field<F>(&mut self, f_name: &str, f_idx: usize, f: F)
71 -> Result<(), Self::Error>
72 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
74 fn emit_tuple<F>(&mut self, len: usize, f: F) -> Result<(), Self::Error>
75 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
76 fn emit_tuple_arg<F>(&mut self, idx: usize, f: F) -> Result<(), Self::Error>
77 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
79 fn emit_tuple_struct<F>(&mut self, name: &str, len: usize, f: F)
80 -> Result<(), Self::Error>
81 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
82 fn emit_tuple_struct_arg<F>(&mut self, f_idx: usize, f: F)
83 -> Result<(), Self::Error>
84 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
87 fn emit_option<F>(&mut self, f: F) -> Result<(), Self::Error>
88 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
89 fn emit_option_none(&mut self) -> Result<(), Self::Error>;
90 fn emit_option_some<F>(&mut self, f: F) -> Result<(), Self::Error>
91 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
93 fn emit_seq<F>(&mut self, len: usize, f: F) -> Result<(), Self::Error>
94 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
95 fn emit_seq_elt<F>(&mut self, idx: usize, f: F) -> Result<(), Self::Error>
96 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
98 fn emit_map<F>(&mut self, len: usize, f: F) -> Result<(), Self::Error>
99 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
100 fn emit_map_elt_key<F>(&mut self, idx: usize, f: F) -> Result<(), Self::Error>
101 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
102 fn emit_map_elt_val<F>(&mut self, idx: usize, f: F) -> Result<(), Self::Error>
103 where F: FnOnce(&mut Self) -> Result<(), Self::Error>;
110 fn read_nil(&mut self) -> Result<(), Self::Error>;
111 fn read_uint(&mut self) -> Result<usize, Self::Error>;
112 fn read_u64(&mut self) -> Result<u64, Self::Error>;
113 fn read_u32(&mut self) -> Result<u32, Self::Error>;
114 fn read_u16(&mut self) -> Result<u16, Self::Error>;
115 fn read_u8(&mut self) -> Result<u8, Self::Error>;
116 fn read_int(&mut self) -> Result<isize, Self::Error>;
117 fn read_i64(&mut self) -> Result<i64, Self::Error>;
118 fn read_i32(&mut self) -> Result<i32, Self::Error>;
119 fn read_i16(&mut self) -> Result<i16, Self::Error>;
120 fn read_i8(&mut self) -> Result<i8, Self::Error>;
121 fn read_bool(&mut self) -> Result<bool, Self::Error>;
122 fn read_f64(&mut self) -> Result<f64, Self::Error>;
123 fn read_f32(&mut self) -> Result<f32, Self::Error>;
124 fn read_char(&mut self) -> Result<char, Self::Error>;
125 fn read_str(&mut self) -> Result<String, Self::Error>;
128 fn read_enum<T, F>(&mut self, name: &str, f: F) -> Result<T, Self::Error>
129 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
131 fn read_enum_variant<T, F>(&mut self, names: &[&str], f: F)
132 -> Result<T, Self::Error>
133 where F: FnMut(&mut Self, usize) -> Result<T, Self::Error>;
134 fn read_enum_variant_arg<T, F>(&mut self, a_idx: usize, f: F)
135 -> Result<T, Self::Error>
136 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
138 fn read_enum_struct_variant<T, F>(&mut self, names: &[&str], f: F)
139 -> Result<T, Self::Error>
140 where F: FnMut(&mut Self, usize) -> Result<T, Self::Error>;
141 fn read_enum_struct_variant_field<T, F>(&mut self,
145 -> Result<T, Self::Error>
146 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
148 fn read_struct<T, F>(&mut self, s_name: &str, len: usize, f: F)
149 -> Result<T, Self::Error>
150 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
151 fn read_struct_field<T, F>(&mut self,
155 -> Result<T, Self::Error>
156 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
158 fn read_tuple<T, F>(&mut self, len: usize, f: F) -> Result<T, Self::Error>
159 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
160 fn read_tuple_arg<T, F>(&mut self, a_idx: usize, f: F)
161 -> Result<T, Self::Error>
162 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
164 fn read_tuple_struct<T, F>(&mut self, s_name: &str, len: usize, f: F)
165 -> Result<T, Self::Error>
166 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
167 fn read_tuple_struct_arg<T, F>(&mut self, a_idx: usize, f: F)
168 -> Result<T, Self::Error>
169 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
171 // Specialized types:
172 fn read_option<T, F>(&mut self, f: F) -> Result<T, Self::Error>
173 where F: FnMut(&mut Self, bool) -> Result<T, Self::Error>;
175 fn read_seq<T, F>(&mut self, f: F) -> Result<T, Self::Error>
176 where F: FnOnce(&mut Self, usize) -> Result<T, Self::Error>;
177 fn read_seq_elt<T, F>(&mut self, idx: usize, f: F) -> Result<T, Self::Error>
178 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
180 fn read_map<T, F>(&mut self, f: F) -> Result<T, Self::Error>
181 where F: FnOnce(&mut Self, usize) -> Result<T, Self::Error>;
182 fn read_map_elt_key<T, F>(&mut self, idx: usize, f: F)
183 -> Result<T, Self::Error>
184 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
185 fn read_map_elt_val<T, F>(&mut self, idx: usize, f: F)
186 -> Result<T, Self::Error>
187 where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
190 fn error(&mut self, err: &str) -> Self::Error;
193 pub trait Encodable {
194 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error>;
197 pub trait Decodable {
198 fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error>;
201 impl Encodable for usize {
202 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
207 impl Decodable for usize {
208 fn decode<D: Decoder>(d: &mut D) -> Result<usize, D::Error> {
213 impl Encodable for u8 {
214 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
219 impl Decodable for u8 {
220 fn decode<D: Decoder>(d: &mut D) -> Result<u8, D::Error> {
225 impl Encodable for u16 {
226 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
231 impl Decodable for u16 {
232 fn decode<D: Decoder>(d: &mut D) -> Result<u16, D::Error> {
237 impl Encodable for u32 {
238 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
243 impl Decodable for u32 {
244 fn decode<D: Decoder>(d: &mut D) -> Result<u32, D::Error> {
249 impl Encodable for u64 {
250 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
255 impl Decodable for u64 {
256 fn decode<D: Decoder>(d: &mut D) -> Result<u64, D::Error> {
261 impl Encodable for isize {
262 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
267 impl Decodable for isize {
268 fn decode<D: Decoder>(d: &mut D) -> Result<isize, D::Error> {
273 impl Encodable for i8 {
274 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
279 impl Decodable for i8 {
280 fn decode<D: Decoder>(d: &mut D) -> Result<i8, D::Error> {
285 impl Encodable for i16 {
286 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
291 impl Decodable for i16 {
292 fn decode<D: Decoder>(d: &mut D) -> Result<i16, D::Error> {
297 impl Encodable for i32 {
298 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
303 impl Decodable for i32 {
304 fn decode<D: Decoder>(d: &mut D) -> Result<i32, D::Error> {
309 impl Encodable for i64 {
310 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
315 impl Decodable for i64 {
316 fn decode<D: Decoder>(d: &mut D) -> Result<i64, D::Error> {
321 impl Encodable for str {
322 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
327 impl Encodable for String {
328 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
329 s.emit_str(&self[..])
333 impl Decodable for String {
334 fn decode<D: Decoder>(d: &mut D) -> Result<String, D::Error> {
339 impl Encodable for f32 {
340 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
345 impl Decodable for f32 {
346 fn decode<D: Decoder>(d: &mut D) -> Result<f32, D::Error> {
351 impl Encodable for f64 {
352 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
357 impl Decodable for f64 {
358 fn decode<D: Decoder>(d: &mut D) -> Result<f64, D::Error> {
363 impl Encodable for bool {
364 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
369 impl Decodable for bool {
370 fn decode<D: Decoder>(d: &mut D) -> Result<bool, D::Error> {
375 impl Encodable for char {
376 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
381 impl Decodable for char {
382 fn decode<D: Decoder>(d: &mut D) -> Result<char, D::Error> {
387 impl Encodable for () {
388 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
393 impl Decodable for () {
394 fn decode<D: Decoder>(d: &mut D) -> Result<(), D::Error> {
399 impl<'a, T: ?Sized + Encodable> Encodable for &'a T {
400 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
405 impl<T: ?Sized + Encodable> Encodable for Box<T> {
406 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
411 impl< T: Decodable> Decodable for Box<T> {
412 fn decode<D: Decoder>(d: &mut D) -> Result<Box<T>, D::Error> {
413 Ok(box try!(Decodable::decode(d)))
417 impl< T: Decodable> Decodable for Box<[T]> {
418 fn decode<D: Decoder>(d: &mut D) -> Result<Box<[T]>, D::Error> {
419 let v: Vec<T> = try!(Decodable::decode(d));
420 Ok(v.into_boxed_slice())
424 impl<T:Encodable> Encodable for Rc<T> {
426 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
431 impl<T:Decodable> Decodable for Rc<T> {
433 fn decode<D: Decoder>(d: &mut D) -> Result<Rc<T>, D::Error> {
434 Ok(Rc::new(try!(Decodable::decode(d))))
438 impl<T:Encodable> Encodable for [T] {
439 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
440 s.emit_seq(self.len(), |s| {
441 for (i, e) in self.iter().enumerate() {
442 try!(s.emit_seq_elt(i, |s| e.encode(s)))
449 impl<T:Encodable> Encodable for Vec<T> {
450 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
451 s.emit_seq(self.len(), |s| {
452 for (i, e) in self.iter().enumerate() {
453 try!(s.emit_seq_elt(i, |s| e.encode(s)))
460 impl<T:Decodable> Decodable for Vec<T> {
461 fn decode<D: Decoder>(d: &mut D) -> Result<Vec<T>, D::Error> {
462 d.read_seq(|d, len| {
463 let mut v = Vec::with_capacity(len);
465 v.push(try!(d.read_seq_elt(i, |d| Decodable::decode(d))));
472 impl<T:Encodable> Encodable for Option<T> {
473 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
476 None => s.emit_option_none(),
477 Some(ref v) => s.emit_option_some(|s| v.encode(s)),
483 impl<T:Decodable> Decodable for Option<T> {
484 fn decode<D: Decoder>(d: &mut D) -> Result<Option<T>, D::Error> {
485 d.read_option(|d, b| {
487 Ok(Some(try!(Decodable::decode(d))))
496 ($name:ident, $($other:ident,)*) => (tuple! { $($other,)* })
499 /// Evaluates to the number of identifiers passed to it, for example: `count_idents!(a, b, c) == 3
500 macro_rules! count_idents {
502 ($_i:ident, $($rest:ident,)*) => { 1 + count_idents!($($rest,)*) }
507 ( $($name:ident,)+ ) => (
508 impl<$($name:Decodable),*> Decodable for ($($name,)*) {
509 #[allow(non_snake_case)]
510 fn decode<D: Decoder>(d: &mut D) -> Result<($($name,)*), D::Error> {
511 let len: usize = count_idents!($($name,)*);
512 d.read_tuple(len, |d| {
514 let ret = ($(try!(d.read_tuple_arg({ i+=1; i-1 },
515 |d| -> Result<$name,D::Error> {
522 impl<$($name:Encodable),*> Encodable for ($($name,)*) {
523 #[allow(non_snake_case)]
524 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
525 let ($(ref $name,)*) = *self;
527 $(let $name = $name; n += 1;)*
528 s.emit_tuple(n, |s| {
530 $(try!(s.emit_tuple_arg({ i+=1; i-1 }, |s| $name.encode(s)));)*
539 tuple! { T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, }
541 impl Encodable for path::PathBuf {
542 fn encode<S: Encoder>(&self, e: &mut S) -> Result<(), S::Error> {
543 self.to_str().unwrap().encode(e)
547 impl Decodable for path::PathBuf {
548 fn decode<D: Decoder>(d: &mut D) -> Result<path::PathBuf, D::Error> {
549 let bytes: String = try!(Decodable::decode(d));
550 Ok(path::PathBuf::from(bytes))
554 impl<T: Encodable + Copy> Encodable for Cell<T> {
555 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
560 impl<T: Decodable + Copy> Decodable for Cell<T> {
561 fn decode<D: Decoder>(d: &mut D) -> Result<Cell<T>, D::Error> {
562 Ok(Cell::new(try!(Decodable::decode(d))))
567 // Should use `try_borrow`, returning a
568 // `encoder.error("attempting to Encode borrowed RefCell")`
569 // from `encode` when `try_borrow` returns `None`.
571 impl<T: Encodable> Encodable for RefCell<T> {
572 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
573 self.borrow().encode(s)
577 impl<T: Decodable> Decodable for RefCell<T> {
578 fn decode<D: Decoder>(d: &mut D) -> Result<RefCell<T>, D::Error> {
579 Ok(RefCell::new(try!(Decodable::decode(d))))
583 impl<T:Encodable> Encodable for Arc<T> {
584 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
589 impl<T:Decodable+Send+Sync> Decodable for Arc<T> {
590 fn decode<D: Decoder>(d: &mut D) -> Result<Arc<T>, D::Error> {
591 Ok(Arc::new(try!(Decodable::decode(d))))
595 // ___________________________________________________________________________
598 pub trait EncoderHelpers: Encoder {
599 fn emit_from_vec<T, F>(&mut self, v: &[T], f: F)
600 -> Result<(), Self::Error>
601 where F: FnMut(&mut Self, &T) -> Result<(), Self::Error>;
604 impl<S:Encoder> EncoderHelpers for S {
605 fn emit_from_vec<T, F>(&mut self, v: &[T], mut f: F) -> Result<(), S::Error> where
606 F: FnMut(&mut S, &T) -> Result<(), S::Error>,
608 self.emit_seq(v.len(), |this| {
609 for (i, e) in v.iter().enumerate() {
610 try!(this.emit_seq_elt(i, |this| {
619 pub trait DecoderHelpers: Decoder {
620 fn read_to_vec<T, F>(&mut self, f: F)
621 -> Result<Vec<T>, Self::Error> where
622 F: FnMut(&mut Self) -> Result<T, Self::Error>;
625 impl<D: Decoder> DecoderHelpers for D {
626 fn read_to_vec<T, F>(&mut self, mut f: F) -> Result<Vec<T>, D::Error> where F:
627 FnMut(&mut D) -> Result<T, D::Error>,
629 self.read_seq(|this, len| {
630 let mut v = Vec::with_capacity(len);
632 v.push(try!(this.read_seq_elt(i, |this| f(this))));