serde/de.rs
2014-05-24 14:08:35 -07:00

941 lines
24 KiB
Rust

extern crate collections;
use std::hash::Hash;
use std::num;
use std::result;
use collections::HashMap;
#[deriving(Clone, Eq)]
pub enum Token {
Null,
Bool(bool),
Int(int),
I8(i8),
I16(i16),
I32(i32),
I64(i64),
Uint(uint),
U8(u8),
U16(u16),
U32(u32),
U64(u64),
F32(f32),
F64(f64),
Char(char),
Str(&'static str),
StrBuf(StrBuf),
Option(bool),
TupleStart(uint),
StructStart(&'static str),
StructField(&'static str),
EnumStart(&'static str),
EnumVariant(&'static str),
SeqStart(uint),
MapStart(uint),
Sep,
End,
}
macro_rules! expect_token {
() => {
match self.next() {
Some(token) => token,
None => { return Err(self.end_of_stream_error()); }
}
}
}
macro_rules! match_token {
($( $variant:pat => $expr:expr ),+) => {
match expect_token!() {
$( Ok($variant) => $expr ),+,
Ok(_) => { return Err(self.syntax_error()); }
Err(err) => { return Err(err); }
}
}
}
macro_rules! to_result {
($expr:expr, $err:expr) => {
match $expr {
Some(value) => Ok(value),
None => Err($err),
}
}
}
pub trait Deserializer<E>: Iterator<Result<Token, E>> {
fn end_of_stream_error(&self) -> E;
fn syntax_error(&self) -> E;
#[inline]
fn expect_null(&mut self, token: Token) -> Result<(), E> {
match token {
Null => Ok(()),
TupleStart(_) => {
match self.next() {
Some(Ok(End)) => Ok(()),
Some(Ok(_)) => Err(self.syntax_error()),
Some(Err(err)) => Err(err),
None => Err(self.end_of_stream_error()),
}
}
_ => Err(self.syntax_error()),
}
}
/*
#[inline]
fn expect_bool(&mut self) -> Result<bool, E> {
match_token! {
Bool(value) => Ok(value)
}
}
*/
#[inline]
fn expect_num<T: NumCast>(&mut self, token: Token) -> Result<T, E> {
match token {
Int(x) => to_result!(num::cast(x), self.syntax_error()),
I8(x) => to_result!(num::cast(x), self.syntax_error()),
I16(x) => to_result!(num::cast(x), self.syntax_error()),
I32(x) => to_result!(num::cast(x), self.syntax_error()),
I64(x) => to_result!(num::cast(x), self.syntax_error()),
Uint(x) => to_result!(num::cast(x), self.syntax_error()),
U8(x) => to_result!(num::cast(x), self.syntax_error()),
U16(x) => to_result!(num::cast(x), self.syntax_error()),
U32(x) => to_result!(num::cast(x), self.syntax_error()),
U64(x) => to_result!(num::cast(x), self.syntax_error()),
F32(x) => to_result!(num::cast(x), self.syntax_error()),
F64(x) => to_result!(num::cast(x), self.syntax_error()),
_ => { return Err(self.syntax_error()); }
}
}
/*
#[inline]
fn expect_char(&mut self) -> Result<char, E> {
match_token! {
Char(value) => Ok(value)
}
}
#[inline]
fn expect_str(&mut self) -> Result<&'static str, E> {
match_token! {
Str(value) => Ok(value)
}
}
*/
#[inline]
fn expect_strbuf(&mut self, token: Token) -> Result<StrBuf, E> {
match token {
Str(value) => Ok(value.to_strbuf()),
StrBuf(value) => Ok(value),
_ => Err(self.syntax_error()),
}
}
/*
#[inline]
fn expect_option<
T: Deserializable<E, Self>
>(&mut self) -> Result<Option<T>, E> {
match_token! {
Option(false) => Ok(None),
Option(true) => {
let value: T = try!(Deserializable::deserialize(self));
Ok(Some(value))
}
}
}
*/
#[inline]
fn expect_tuple_start(&mut self, token: Token, len: uint) -> Result<(), E> {
match token {
TupleStart(l) => {
if len == l {
Ok(())
} else {
Err(self.syntax_error())
}
}
_ => Err(self.syntax_error()),
}
}
/*
#[inline]
fn expect_tuple_elt<T: Deserializable<E, Self>>(&mut self) -> Result<T, E> {
match_token! {
Sep => Deserializable::deserialize(self)
}
}
#[inline]
fn expect_struct_start(&mut self, name: &str) -> Result<(), E> {
match_token! {
StructStart(n) => {
if name == n {
Ok(())
} else {
Err(self.syntax_error())
}
}
}
}
#[inline]
fn expect_struct_field<
T: Deserializable<E, Self>
>(&mut self, name: &str) -> Result<T, E> {
match_token! {
StructField(n) => {
if name == n {
Deserializable::deserialize(self)
} else {
Err(self.syntax_error())
}
}
}
}
*/
#[inline]
fn expect_enum_start<'a>(&mut self, token: Token, name: &str, variants: &[&str]) -> Result<uint, E> {
match token {
EnumStart(n) => {
if name == n {
match_token! {
EnumVariant(n) => {
match variants.iter().position(|variant| *variant == n) {
Some(position) => Ok(position),
None => Err(self.syntax_error()),
}
}
}
} else {
Err(self.syntax_error())
}
}
_ => Err(self.syntax_error()),
}
}
#[inline]
fn expect_collection<
T: Deserializable<E, Self>,
C: FromIterator<T>
>(&mut self, token: Token) -> Result<C, E> {
// By default we don't care what our source input was. We can take
// anything that's a Collection<T>. We'll error out later if the types
// are wrong.
let len = match token {
TupleStart(len) => len,
SeqStart(len) => len,
MapStart(len) => len,
_ => { return Err(self.syntax_error()); }
};
expect_rest_of_collection(self, len)
}
#[inline]
fn expect_seq<
T: Deserializable<E, Self>,
C: FromIterator<T>
>(&mut self, token: Token) -> Result<C, E> {
let len = match token {
SeqStart(len) => len,
_ => { return Err(self.syntax_error()); }
};
expect_rest_of_collection(self, len)
}
#[inline]
fn expect_map<
K: Deserializable<E, Self>,
V: Deserializable<E, Self>,
C: FromIterator<(K, V)>
>(&mut self, token: Token) -> Result<C, E> {
let len = match token {
MapStart(len) => len,
_ => { return Err(self.syntax_error()); }
};
expect_rest_of_collection(self, len)
}
#[inline]
fn expect_end(&mut self) -> Result<(), E> {
match self.next() {
Some(Ok(End)) => Ok(()),
Some(Ok(_)) => Err(self.syntax_error()),
Some(Err(err)) => Err(err),
None => Err(self.end_of_stream_error()),
}
}
}
//////////////////////////////////////////////////////////////////////////////
fn expect_rest_of_collection<
E,
D: Deserializer<E>,
T: Deserializable<E, D>,
C: FromIterator<T>
>(d: &mut D, len: uint) -> Result<C, E> {
let iter = d.by_ref().batch(|d| {
let d = d.iter();
match d.next() {
Some(Ok(End)) => None,
Some(Ok(token)) => {
let value: Result<T, E> = Deserializable::deserialize_token(d, token);
Some(value)
}
Some(Err(e)) => Some(Err(e)),
None => Some(Err(d.end_of_stream_error())),
}
});
result::collect_with_capacity(iter, len)
}
//////////////////////////////////////////////////////////////////////////////
pub trait Deserializable<E, D: Deserializer<E>> {
#[inline]
fn deserialize(d: &mut D) -> Result<Self, E> {
match d.next() {
Some(Ok(token)) => Deserializable::deserialize_token(d, token),
Some(Err(err)) => Err(err),
None => Err(d.end_of_stream_error()),
}
}
fn deserialize_token(d: &mut D, token: Token) -> Result<Self, E>;
}
//////////////////////////////////////////////////////////////////////////////
macro_rules! impl_deserializable {
($ty:ty, $method:ident) => {
impl<
E,
D: Deserializer<E>
> Deserializable<E, D> for $ty {
#[inline]
fn deserialize_token(d: &mut D, token: Token) -> Result<$ty, E> {
d.$method(token)
}
}
}
}
//impl_deserializable!(bool, expect_bool)
impl_deserializable!(int, expect_num)
impl_deserializable!(i8, expect_num)
impl_deserializable!(i16, expect_num)
impl_deserializable!(i32, expect_num)
impl_deserializable!(i64, expect_num)
impl_deserializable!(uint, expect_num)
impl_deserializable!(u8, expect_num)
impl_deserializable!(u16, expect_num)
impl_deserializable!(u32, expect_num)
impl_deserializable!(u64, expect_num)
impl_deserializable!(f32, expect_num)
impl_deserializable!(f64, expect_num)
/*
impl_deserializable!(char, expect_char)
impl_deserializable!(&'static str, expect_str)
*/
impl_deserializable!(StrBuf, expect_strbuf)
/*
//////////////////////////////////////////////////////////////////////////////
impl<
E,
D: Deserializer<E>,
T: Deserializable<E, D>
> Deserializable<E, D> for Option<T> {
#[inline]
fn deserialize(d: &mut D) -> Result<Option<T>, E> {
d.expect_option()
}
}
*/
//////////////////////////////////////////////////////////////////////////////
impl<
E,
D: Deserializer<E>,
T: Deserializable<E, D>
> Deserializable<E, D> for Vec<T> {
#[inline]
fn deserialize_token(d: &mut D, token: Token) -> Result<Vec<T>, E> {
d.expect_collection(token)
}
}
/*
impl<
E,
D: Deserializer<E>,
K: Deserializable<E, D> + TotalEq + Hash,
V: Deserializable<E, D>
> Deserializable<E, D> for HashMap<K, V> {
#[inline]
fn deserialize(d: &mut D) -> Result<HashMap<K, V>, E> {
d.expect_map()
}
}
*/
//////////////////////////////////////////////////////////////////////////////
impl<
E,
D: Deserializer<E>
> Deserializable<E, D> for () {
#[inline]
fn deserialize_token(d: &mut D, token: Token) -> Result<(), E> {
d.expect_null(token)
}
}
//////////////////////////////////////////////////////////////////////////////
macro_rules! peel(($name:ident, $($other:ident,)*) => (deserialize_tuple!($($other,)*)))
macro_rules! deserialize_tuple (
() => ();
( $($name:ident,)+ ) => (
impl<
E,
D: Deserializer<E>,
$($name:Deserializable<E, D>),*
> Deserializable<E, D> for ($($name,)*) {
#[inline]
#[allow(uppercase_variables)]
fn deserialize_token(d: &mut D, token: Token) -> Result<($($name,)*), E> {
// FIXME: how can we count macro args?
let mut len = 0;
$({ let $name = 1; len += $name; })*;
try!(d.expect_tuple_start(token, len));
let result = ($({
let $name = try!(Deserializable::deserialize(d));
$name
},)*);
match d.next() {
Some(Ok(End)) => Ok(result),
Some(Ok(_)) => Err(d.syntax_error()),
Some(Err(err)) => Err(err),
None => Err(d.end_of_stream_error()),
}
}
}
peel!($($name,)*)
)
)
deserialize_tuple! { T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, }
//////////////////////////////////////////////////////////////////////////////
/*
#[cfg(test)]
mod tests {
use collections::HashMap;
use test::Bencher;
use serialize::Decoder;
use super::{Token, Null, Int, Uint, Str, StrBuf, Char, Option};
use super::{TupleStart, StructStart, StructField, EnumStart, EnumVariant};
use super::{SeqStart, MapStart, Sep, End};
use super::{Deserializer, Deserializable};
//////////////////////////////////////////////////////////////////////////////
#[deriving(Clone, Eq, Show, Decodable)]
struct Inner {
a: (),
b: uint,
c: HashMap<StrBuf, Option<char>>,
}
impl<E, D: Deserializer<E>> Deserializable<E, D> for Inner {
#[inline]
fn deserialize(d: &mut D) -> Result<Inner, E> {
try!(d.expect_struct_start("Inner"));
let a = try!(d.expect_struct_field("a"));
let b = try!(d.expect_struct_field("b"));
let c = try!(d.expect_struct_field("c"));
try!(d.expect_end());
Ok(Inner { a: a, b: b, c: c })
}
}
//////////////////////////////////////////////////////////////////////////////
#[deriving(Clone, Eq, Show, Decodable)]
struct Outer {
inner: Vec<Inner>,
}
impl<E, D: Deserializer<E>> Deserializable<E, D> for Outer {
#[inline]
fn deserialize(d: &mut D) -> Result<Outer, E> {
try!(d.expect_struct_start("Outer"));
let inner = try!(d.expect_struct_field("inner"));
try!(d.expect_end());
Ok(Outer { inner: inner })
}
}
//////////////////////////////////////////////////////////////////////////////
#[deriving(Clone, Eq, Show, Decodable)]
enum Animal {
Dog,
Frog(StrBuf, int)
}
impl<E, D: Deserializer<E>> Deserializable<E, D> for Animal {
#[inline]
fn deserialize(d: &mut D) -> Result<Animal, E> {
match try!(d.expect_enum_start("Animal", ["Dog", "Frog"])) {
0 => {
try!(d.expect_end());
Ok(Dog)
}
1 => {
let x0 = try!(Deserializable::deserialize(d));
let x1 = try!(Deserializable::deserialize(d));
try!(d.expect_end());
Ok(Frog(x0, x1))
}
_ => unreachable!(),
}
}
}
//////////////////////////////////////////////////////////////////////////////
#[deriving(Show)]
enum Error {
EndOfStream,
SyntaxError,
}
//////////////////////////////////////////////////////////////////////////////
struct TokenDeserializer {
tokens: Vec<Token>,
}
impl TokenDeserializer {
#[inline]
fn new(tokens: Vec<Token>) -> TokenDeserializer {
TokenDeserializer {
tokens: tokens,
}
}
}
impl Iterator<Result<Token, Error>> for TokenDeserializer {
#[inline]
fn next(&mut self) -> Option<Result<Token, Error>> {
match self.tokens.shift() {
None => None,
Some(token) => Some(Ok(token)),
}
}
}
impl Deserializer<Error> for TokenDeserializer {
#[inline]
fn end_of_stream_error(&self) -> Error {
EndOfStream
}
#[inline]
fn syntax_error(&self) -> Error {
SyntaxError
}
}
//////////////////////////////////////////////////////////////////////////////
#[test]
fn test_tokens_int() {
let tokens = vec!(
Int(5),
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: int = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, 5);
}
#[test]
fn test_tokens_str() {
let tokens = vec!(
Str("a"),
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: &'static str = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, "a");
}
#[test]
fn test_tokens_strbuf() {
let tokens = vec!(
StrBuf("a".to_strbuf()),
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: StrBuf = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, "a".to_strbuf());
}
#[test]
fn test_tokens_null() {
let tokens = vec!(
Null,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: () = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, ());
}
#[test]
fn test_tokens_tuple_empty() {
let tokens = vec!(
TupleStart(0),
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: () = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, ());
}
#[test]
fn test_tokens_option_none() {
let tokens = vec!(
Option(false),
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Option<int> = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, None);
}
#[test]
fn test_tokens_option_some() {
let tokens = vec!(
Option(true),
Int(5),
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Option<int> = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, Some(5));
}
#[test]
fn test_tokens_tuple() {
let tokens = vec!(
TupleStart(2),
Sep,
Int(5),
Sep,
StrBuf("a".to_strbuf()),
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: (int, StrBuf) = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, (5, "a".to_strbuf()));
}
#[test]
fn test_tokens_tuple_compound() {
let tokens = vec!(
TupleStart(3),
Sep,
Null,
Sep,
TupleStart(0),
End,
Sep,
TupleStart(2),
Sep,
Int(5),
Sep,
StrBuf("a".to_strbuf()),
End,
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: ((), (), (int, StrBuf)) = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, ((), (), (5, "a".to_strbuf())));
}
#[test]
fn test_tokens_struct_empty() {
let tokens = vec!(
StructStart("Outer"),
StructField("inner"),
SeqStart(0),
End,
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Outer = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, Outer { inner: vec!() });
}
#[test]
fn test_tokens_struct() {
let tokens = vec!(
StructStart("Outer"),
StructField("inner"),
SeqStart(1),
Sep,
StructStart("Inner"),
StructField("a"),
Null,
StructField("b"),
Uint(5),
StructField("c"),
MapStart(1),
Sep,
TupleStart(2),
Sep,
StrBuf("abc".to_strbuf()),
Sep,
Option(true),
Char('c'),
End,
End,
End,
End,
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Outer = Deserializable::deserialize(&mut deserializer).unwrap();
let mut map = HashMap::new();
map.insert("abc".to_strbuf(), Some('c'));
assert_eq!(
value,
Outer {
inner: vec!(
Inner {
a: (),
b: 5,
c: map,
},
)
});
}
#[test]
fn test_tokens_enum() {
let tokens = vec!(
EnumStart("Animal"),
EnumVariant("Dog"),
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Animal = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, Dog);
let tokens = vec!(
EnumStart("Animal"),
EnumVariant("Frog"),
StrBuf("Henry".to_strbuf()),
Int(349),
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Animal = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, Frog("Henry".to_strbuf(), 349));
}
#[test]
fn test_tokens_vec_empty() {
let tokens = vec!(
SeqStart(0),
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Vec<int> = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, vec!());
}
#[test]
fn test_tokens_vec() {
let tokens = vec!(
SeqStart(3),
Sep,
Int(5),
Sep,
Int(6),
Sep,
Int(7),
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Vec<int> = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, vec!(5, 6, 7));
}
#[test]
fn test_tokens_vec_compound() {
let tokens = vec!(
SeqStart(0),
Sep,
SeqStart(1),
Sep,
Int(1),
End,
Sep,
SeqStart(2),
Sep,
Int(2),
Sep,
Int(3),
End,
Sep,
SeqStart(3),
Sep,
Int(4),
Sep,
Int(5),
Sep,
Int(6),
End,
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: Vec<Vec<int>> = Deserializable::deserialize(&mut deserializer).unwrap();
assert_eq!(value, vec!(vec!(1), vec!(2, 3), vec!(4, 5, 6)));
}
#[test]
fn test_tokens_hashmap() {
let tokens = vec!(
MapStart(2),
Sep,
TupleStart(2),
Sep,
Int(5),
Sep,
StrBuf("a".to_strbuf()),
End,
Sep,
TupleStart(2),
Sep,
Int(6),
Sep,
StrBuf("b".to_strbuf()),
End,
End,
);
let mut deserializer = TokenDeserializer::new(tokens);
let value: HashMap<int, StrBuf> = Deserializable::deserialize(&mut deserializer).unwrap();
let mut map = HashMap::new();
map.insert(5, "a".to_strbuf());
map.insert(6, "b".to_strbuf());
assert_eq!(value, map);
}
#[bench]
fn bench_token_deserializer(b: &mut Bencher) {
b.iter(|| {
let tokens = vec!(
SeqStart(3),
Sep,
Int(5),
Sep,
Int(6),
Sep,
Int(7),
End,
);
let mut d = TokenDeserializer::new(tokens);
let value: Vec<int> = Deserializable::deserialize(&mut d).unwrap();
assert_eq!(value, vec!(5, 6, 7));
})
}
}
*/