serde/ser.rs

// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::collections::{HashMap, TreeMap};
use std::hash::Hash;

//////////////////////////////////////////////////////////////////////////////

pub trait Serializer<E> {
    fn serialize_null(&mut self) -> Result<(), E>;

    fn serialize_bool(&mut self, v: bool) -> Result<(), E>;

    #[inline]
    fn serialize_int(&mut self, v: int) -> Result<(), E> {
        self.serialize_i64(v as i64)
    }

    #[inline]
    fn serialize_i8(&mut self, v: i8) -> Result<(), E> {
        self.serialize_i64(v as i64)
    }

    #[inline]
    fn serialize_i16(&mut self, v: i16) -> Result<(), E> {
        self.serialize_i64(v as i64)
    }

    #[inline]
    fn serialize_i32(&mut self, v: i32) -> Result<(), E> {
        self.serialize_i64(v as i64)
    }

    #[inline]
    fn serialize_i64(&mut self, v: i64) -> Result<(), E>;

    #[inline]
    fn serialize_uint(&mut self, v: uint) -> Result<(), E> {
        self.serialize_u64(v as u64)
    }

    #[inline]
    fn serialize_u8(&mut self, v: u8) -> Result<(), E> {
        self.serialize_u64(v as u64)
    }

    #[inline]
    fn serialize_u16(&mut self, v: u16) -> Result<(), E> {
        self.serialize_u64(v as u64)
    }

    #[inline]
    fn serialize_u32(&mut self, v: u32) -> Result<(), E> {
        self.serialize_u64(v as u64)
    }

    #[inline]
    fn serialize_u64(&mut self, v: u64) -> Result<(), E>;

    #[inline]
    fn serialize_f32(&mut self, v: f32) -> Result<(), E> {
        self.serialize_f64(v as f64)
    }

    fn serialize_f64(&mut self, v: f64) -> Result<(), E>;

    fn serialize_char(&mut self, v: char) -> Result<(), E>;

    fn serialize_str(&mut self, v: &str) -> Result<(), E>;

    fn serialize_tuple_start(&mut self, len: uint) -> Result<(), E>;
    fn serialize_tuple_sep<T: Serializable>(&mut self, v: &T) -> Result<(), E>;
    fn serialize_tuple_end(&mut self) -> Result<(), E>;

    fn serialize_struct_start(&mut self, name: &str, len: uint) -> Result<(), E>;
    fn serialize_struct_sep<T: Serializable>(&mut self, name: &str, v: &T) -> Result<(), E>;
    fn serialize_struct_end(&mut self) -> Result<(), E>;

    fn serialize_enum_start(&mut self, name: &str, variant: &str, len: uint) -> Result<(), E>;
    fn serialize_enum_sep<T: Serializable>(&mut self, v: &T) -> Result<(), E>;
    fn serialize_enum_end(&mut self) -> Result<(), E>;

    fn serialize_option<T: Serializable>(&mut self, v: &Option<T>) -> Result<(), E>;

    fn serialize_seq<
        T: Serializable,
        Iter: Iterator<T>
    >(&mut self, iter: Iter) -> Result<(), E>;

    fn serialize_map<
        K: Serializable,
        V: Serializable,
        Iter: Iterator<(K, V)>
    >(&mut self, iter: Iter) -> Result<(), E>;
}

//////////////////////////////////////////////////////////////////////////////

pub trait Serializable {
    fn serialize<
        S: Serializer<E>,
        E
    >(&self, s: &mut S) -> Result<(), E>;
}

//////////////////////////////////////////////////////////////////////////////

macro_rules! impl_serializable {
    ($ty:ty, $method:ident, $variant:expr) => {
        impl<'a> Serializable for $ty {
            #[inline]
            fn serialize<
                S: Serializer<E>,
                E
            >(&self, s: &mut S) -> Result<(), E> {
                s.$method($variant)
            }
        }
    }
}

impl_serializable!(bool, serialize_bool, *self)
impl_serializable!(int, serialize_int, *self)
impl_serializable!(i8, serialize_i8, *self)
impl_serializable!(i16, serialize_i16, *self)
impl_serializable!(i32, serialize_i32, *self)
impl_serializable!(i64, serialize_i64, *self)
impl_serializable!(uint, serialize_uint, *self)
impl_serializable!(u8, serialize_u8, *self)
impl_serializable!(u16, serialize_u16, *self)
impl_serializable!(u32, serialize_u32, *self)
impl_serializable!(u64, serialize_u64, *self)
impl_serializable!(f32, serialize_f32, *self)
impl_serializable!(f64, serialize_f64, *self)
impl_serializable!(char, serialize_char, *self)
impl_serializable!(&'a str, serialize_str, *self)
impl_serializable!(String, serialize_str, self.as_slice())

impl<
    'a,
    T: Serializable
> Serializable for &'a T {
    #[inline]
    fn serialize<
        S: Serializer<E>,
        E
    >(&self, s: &mut S) -> Result<(), E> {
        (*self).serialize(s)
    }
}

//////////////////////////////////////////////////////////////////////////////

impl<
    T: Serializable
> Serializable for Option<T> {
    #[inline]
    fn serialize<
        S: Serializer<E>,
        E
    >(&self, s: &mut S) -> Result<(), E> {
        s.serialize_option(self)
    }
}

//////////////////////////////////////////////////////////////////////////////

impl<
    T: Serializable
> Serializable for Vec<T> {
    #[inline]
    fn serialize<
        S: Serializer<E>,
        E
    >(&self, s: &mut S) -> Result<(), E> {
        s.serialize_seq(self.iter())
    }
}

//////////////////////////////////////////////////////////////////////////////

impl<
    K: Serializable + Eq + Hash,
    V: Serializable
> Serializable for HashMap<K, V> {
    #[inline]
    fn serialize<
        S: Serializer<E>,
        E
    >(&self, s: &mut S) -> Result<(), E> {
        s.serialize_map(self.iter())
    }
}

impl<
    K: Serializable + Ord,
    V: Serializable
> Serializable for TreeMap<K, V> {
    #[inline]
    fn serialize<
        S: Serializer<E>,
        E
    >(&self, s: &mut S) -> Result<(), E> {
        s.serialize_map(self.iter())
    }
}

//////////////////////////////////////////////////////////////////////////////

macro_rules! peel {
    ($name:ident, $($other:ident,)*) => (impl_serialize_tuple!($($other,)*))
}

macro_rules! impl_serialize_tuple {
    () => {
        impl Serializable for () {
            #[inline]
            fn serialize<
                S: Serializer<E>,
                E
            >(&self, s: &mut S) -> Result<(), E> {
                s.serialize_null()
            }
        }
    };
    ( $($name:ident,)+ ) => {
        impl<
            $($name:Serializable),*
        > Serializable for ($($name,)*) {
            #[inline]
            #[allow(uppercase_variables)]
            fn serialize<
                S: Serializer<E>,
                E
            >(&self, s: &mut S) -> Result<(), E> {
                // FIXME: how can we count macro args?
                let mut len = 0;
                $({ let $name = 1; len += $name; })*;

                let ($(ref $name,)*) = *self;

                try!(s.serialize_tuple_start(len));
                $(
                    try!(s.serialize_tuple_sep($name));
                 )*
                s.serialize_tuple_end()
            }
        }
        peel!($($name,)*)
    }
}

impl_serialize_tuple! { T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, }

//////////////////////////////////////////////////////////////////////////////

#[cfg(test)]
mod tests {
    use std::collections::{HashMap, TreeMap};

    use serialize::Decoder;

    use super::{Serializer, Serializable};

    //////////////////////////////////////////////////////////////////////////////

    #[deriving(Clone, PartialEq, Show, Decodable)]
    struct Inner {
        a: (),
        b: uint,
        c: HashMap<String, Option<char>>,
    }

    impl Serializable for Inner {
        #[inline]
        fn serialize<
            S: Serializer<E>,
            E
        >(&self, s: &mut S) -> Result<(), E> {
            try!(s.serialize_struct_start("Inner", 3));

            try!(s.serialize_struct_sep("a", &self.a));
            try!(s.serialize_struct_sep("b", &self.b));
            try!(s.serialize_struct_sep("c", &self.c));

            s.serialize_struct_end()
        }
    }

    //////////////////////////////////////////////////////////////////////////////

    #[deriving(Clone, PartialEq, Show, Decodable)]
    struct Outer {
        inner: Vec<Inner>,
    }

    impl Serializable for Outer {
        #[inline]
        fn serialize<
            S: Serializer<E>,
            E
        >(&self, s: &mut S) -> Result<(), E> {
            try!(s.serialize_struct_start("Outer", 1));

            try!(s.serialize_struct_sep("inner", &self.inner));

            s.serialize_struct_end()
        }
    }

    //////////////////////////////////////////////////////////////////////////////

    #[deriving(Clone, PartialEq, Show, Decodable)]
    enum Animal {
        Dog,
        Frog(String, int)
    }

    impl Serializable for Animal {
        #[inline]
        fn serialize<
            S: Serializer<E>,
            E
        >(&self, s: &mut S) -> Result<(), E> {
            match *self {
                Dog => {
                    try!(s.serialize_enum_start("Animal", "Dog", 0));
                }
                Frog(ref x0, ref x1) => {
                    try!(s.serialize_enum_start("Animal", "Frog", 2));

                    try!(s.serialize_enum_sep(x0));
                    try!(s.serialize_enum_sep(x1));
                }
            }
            s.serialize_enum_end()
        }
    }

    //////////////////////////////////////////////////////////////////////////////

    #[deriving(Clone, PartialEq, Show)]
    pub enum Token<'a> {
        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(&'a str),

        TupleStart(uint),
        TupleSep,
        TupleEnd,

        StructStart(&'a str, uint),
        StructSep(&'a str),
        StructEnd,

        EnumStart(&'a str, &'a str, uint),
        EnumSep,
        EnumEnd,

        Option(bool),

        SeqStart(uint),
        SeqEnd,

        MapStart(uint),
        MapEnd,
    }

    #[deriving(Show)]
    enum Error {
        EndOfStream,
        SyntaxError,
    }

    //////////////////////////////////////////////////////////////////////////////

    struct AssertSerializer<Iter> {
        iter: Iter,
    }

    impl<'a, Iter: Iterator<Token<'a>>> AssertSerializer<Iter> {
        fn new(iter: Iter) -> AssertSerializer<Iter> {
            AssertSerializer {
                iter: iter,
            }
        }

        fn serialize<'b>(&mut self, token: Token<'b>) -> Result<(), Error> {
            let t = match self.iter.next() {
                Some(t) => t,
                None => { fail!(); }
            };

            assert_eq!(t, token);

            Ok(())
        }
    }

    impl<'a, Iter: Iterator<Token<'a>>> Serializer<Error> for AssertSerializer<Iter> {
        fn serialize_null(&mut self) -> Result<(), Error> {
            self.serialize(Null)
        }
        fn serialize_bool(&mut self, v: bool) -> Result<(), Error> {
            self.serialize(Bool(v))
        }
        fn serialize_int(&mut self, v: int) -> Result<(), Error> {
            self.serialize(Int(v))
        }

        fn serialize_i8(&mut self, v: i8) -> Result<(), Error> {
            self.serialize(I8(v))
        }

        fn serialize_i16(&mut self, v: i16) -> Result<(), Error> {
            self.serialize(I16(v))
        }

        fn serialize_i32(&mut self, v: i32) -> Result<(), Error> {
            self.serialize(I32(v))
        }

        fn serialize_i64(&mut self, v: i64) -> Result<(), Error> {
            self.serialize(I64(v))
        }

        fn serialize_uint(&mut self, v: uint) -> Result<(), Error> {
            self.serialize(Uint(v))
        }

        fn serialize_u8(&mut self, v: u8) -> Result<(), Error> {
            self.serialize(U8(v))
        }

        fn serialize_u16(&mut self, v: u16) -> Result<(), Error> {
            self.serialize(U16(v))
        }

        fn serialize_u32(&mut self, v: u32) -> Result<(), Error> {
            self.serialize(U32(v))
        }

        fn serialize_u64(&mut self, v: u64) -> Result<(), Error> {
            self.serialize(U64(v))
        }

        fn serialize_f32(&mut self, v: f32) -> Result<(), Error> {
            self.serialize(F32(v))
        }

        fn serialize_f64(&mut self, v: f64) -> Result<(), Error> {
            self.serialize(F64(v))
        }

        fn serialize_char(&mut self, v: char) -> Result<(), Error> {
            self.serialize(Char(v))
        }

        fn serialize_str(&mut self, v: &str) -> Result<(), Error> {
            self.serialize(Str(v))
        }

        fn serialize_tuple_start(&mut self, len: uint) -> Result<(), Error> {
            self.serialize(TupleStart(len))
        }

        fn serialize_tuple_sep<
            T: Serializable
        >(&mut self, value: &T) -> Result<(), Error> {
            try!(self.serialize(TupleSep));
            value.serialize(self)
        }

        fn serialize_tuple_end(&mut self) -> Result<(), Error> {
            self.serialize(TupleEnd)
        }

        fn serialize_struct_start(&mut self, name: &str, len: uint) -> Result<(), Error> {
            self.serialize(StructStart(name, len))
        }

        fn serialize_struct_sep<
            T: Serializable
        >(&mut self, name: &str, value: &T) -> Result<(), Error> {
            try!(self.serialize(StructSep(name)));
            value.serialize(self)
        }

        fn serialize_struct_end(&mut self) -> Result<(), Error> {
            self.serialize(StructEnd)
        }

        fn serialize_enum_start(&mut self, name: &str, variant: &str, len: uint) -> Result<(), Error> {
            self.serialize(EnumStart(name, variant, len))
        }

        fn serialize_enum_sep<
            T: Serializable
        >(&mut self, value: &T) -> Result<(), Error> {
            try!(self.serialize(EnumSep));
            value.serialize(self)
        }

        fn serialize_enum_end(&mut self) -> Result<(), Error> {
            self.serialize(EnumEnd)
        }

        fn serialize_option<
            T: Serializable
        >(&mut self, v: &Option<T>) -> Result<(), Error> {
            match *v {
                Some(ref v) => {
                    try!(self.serialize(Option(true)));
                    v.serialize(self)
                }
                None => {
                    self.serialize(Option(false))
                }
            }
        }

        fn serialize_seq<
            T: Serializable,
            SeqIter: Iterator<T>
        >(&mut self, mut iter: SeqIter) -> Result<(), Error> {
            let (len, _) = iter.size_hint();
            try!(self.serialize(SeqStart(len)));
            for elt in iter {
                elt.serialize(self).unwrap();
            }
            self.serialize(SeqEnd)
        }

        fn serialize_map<
            K: Serializable,
            V: Serializable,
            MapIter: Iterator<(K, V)>
        >(&mut self, mut iter: MapIter) -> Result<(), Error> {
            let (len, _) = iter.size_hint();
            try!(self.serialize(MapStart(len)));
            for (key, value) in iter {
                try!(key.serialize(self));
                try!(value.serialize(self));
            }
            self.serialize(MapEnd)
        }
    }

    //////////////////////////////////////////////////////////////////////////////

    #[test]
    fn test_tokens_int() {
        let tokens = vec!(
            Int(5)
        );
        let mut serializer = AssertSerializer::new(tokens.move_iter());
        5i.serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_str() {
        let tokens = vec!(
            Str("a"),
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        "a".serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_null() {
        let tokens = vec!(
            Null,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        ().serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_option_none() {
        let tokens = vec!(
            Option(false),
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        None::<int>.serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_option_some() {
        let tokens = vec!(
            Option(true),
            Int(5),
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        Some(5i).serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_tuple() {
        let tokens = vec!(
            TupleStart(2),
                TupleSep,
                Int(5),

                TupleSep,
                Str("a"),
            TupleEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        (5i, "a").serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_tuple_compound() {
        let tokens = vec!(
            TupleStart(3),
                TupleSep,
                Null,

                TupleSep,
                Null,

                TupleSep,
                TupleStart(2),
                    TupleSep,
                    Int(5),

                    TupleSep,
                    Str("a"),
                TupleEnd,
            TupleEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        ((), (), (5i, "a")).serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_struct_empty() {
        let tokens = vec!(
            StructStart("Outer", 1),
                StructSep("inner"),
                SeqStart(0),
                SeqEnd,
            StructEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        Outer { inner: vec!() }.serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_struct() {
        let tokens = vec!(
            StructStart("Outer", 1),
                StructSep("inner"),
                SeqStart(1),
                    StructStart("Inner", 3),
                        StructSep("a"),
                        Null,

                        StructSep("b"),
                        Uint(5),

                        StructSep("c"),
                        MapStart(1),
                            Str("abc"),
                            Option(true),
                            Char('c'),
                        MapEnd,
                    StructEnd,
                SeqEnd,
            StructEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());

        let mut map = HashMap::new();
        map.insert("abc".to_string(), Some('c'));

        Outer {
            inner: vec!(
                Inner {
                    a: (),
                    b: 5,
                    c: map,
                },
            )
        }.serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_enum() {
        let tokens = vec!(
            EnumStart("Animal", "Dog", 0),
            EnumEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        Dog.serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);

        let tokens = vec!(
            EnumStart("Animal", "Frog", 2),
                EnumSep,
                Str("Henry"),

                EnumSep,
                Int(349),
            EnumEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        Frog("Henry".to_string(), 349).serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_vec_empty() {
        let tokens = vec!(
            SeqStart(0),
            SeqEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        let v: Vec<int> = vec!();
        v.serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_vec() {
        let tokens = vec!(
            SeqStart(3),
                Int(5),
                Int(6),
                Int(7),
            SeqEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        (vec!(5i, 6, 7)).serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_vec_compound() {
        let tokens = vec!(
            SeqStart(3),
                SeqStart(1),
                    Int(1),
                SeqEnd,

                SeqStart(2),
                    Int(2),
                    Int(3),
                SeqEnd,

                SeqStart(3),
                    Int(4),
                    Int(5),
                    Int(6),
                SeqEnd,
            SeqEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());
        (vec!(vec!(1i), vec!(2, 3), vec!(4, 5, 6))).serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }

    #[test]
    fn test_tokens_treemap() {
        let tokens = vec!(
            MapStart(2),
                Int(5),
                Str("a"),

                Int(6),
                Str("b"),
            MapEnd,
        );

        let mut serializer = AssertSerializer::new(tokens.move_iter());

        let mut map = TreeMap::new();
        map.insert(5i, "a".to_string());
        map.insert(6i, "b".to_string());

        map.serialize(&mut serializer).unwrap();
        assert_eq!(serializer.iter.next(), None);
    }
}