Factor the Token De/Serializer into serde_test

2026-04-26 18:57:55 +00:00 · 2016-06-28 21:47:54 -07:00
parent fb0e62951f
commit 6d64104375
14 changed files with 718 additions and 638 deletions
@@ -0,0 +1,50 @@
+use serde::{Serialize, Deserialize};
+
+use de::Deserializer;
+use error::Error;
+use ser::Serializer;
+use token::Token;
+
+use std::fmt::Debug;
+
+pub fn assert_tokens<T>(value: &T, tokens: Vec<Token<'static>>)
+    where T: Serialize + Deserialize + PartialEq + Debug,
+{
+    assert_ser_tokens(value, &tokens[..]);
+    assert_de_tokens(value, tokens);
+}
+
+pub fn assert_ser_tokens<T>(value: &T, tokens: &[Token])
+    where T: Serialize,
+{
+    let mut ser = Serializer::new(tokens.iter());
+    assert_eq!(Serialize::serialize(value, &mut ser), Ok(()));
+    assert_eq!(ser.next_token(), None);
+}
+
+// Expect an error deserializing tokens into a T
+pub fn assert_ser_tokens_error<T>(value: &T, tokens: &[Token], error: Error)
+    where T: Serialize + PartialEq + Debug,
+{
+    let mut ser = Serializer::new(tokens.iter());
+    let v: Result<(), Error> = Serialize::serialize(value, &mut ser);
+    assert_eq!(v.as_ref(), Err(&error));
+}
+
+pub fn assert_de_tokens<T>(value: &T, tokens: Vec<Token<'static>>)
+    where T: Deserialize + PartialEq + Debug,
+{
+    let mut de = Deserializer::new(tokens.into_iter());
+    let v: Result<T, Error> = Deserialize::deserialize(&mut de);
+    assert_eq!(v.as_ref(), Ok(value));
+    assert_eq!(de.next_token(), None);
+}
+
+// Expect an error deserializing tokens into a T
+pub fn assert_de_tokens_error<T>(tokens: Vec<Token<'static>>, error: Error)
+    where T: Deserialize + PartialEq + Debug,
+{
+    let mut de = Deserializer::new(tokens.into_iter());
+    let v: Result<T, Error> = Deserialize::deserialize(&mut de);
+    assert_eq!(v, Err(error));
+}
@@ -0,0 +1,854 @@
+use std::iter;
+
+use serde::de::{
+    self,
+    Deserialize,
+    EnumVisitor,
+    MapVisitor,
+    SeqVisitor,
+    VariantVisitor,
+    Visitor,
+};
+
+use error::Error;
+use token::Token;
+
+pub struct Deserializer<I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    tokens: iter::Peekable<I>,
+}
+
+impl<I> Deserializer<I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    pub fn new(tokens: I) -> Deserializer<I> {
+        Deserializer {
+            tokens: tokens.peekable(),
+        }
+    }
+
+    pub fn next_token(&mut self) -> Option<Token<'static>> {
+        self.tokens.next()
+    }
+
+    fn visit_seq<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_seq(DeserializerSeqVisitor {
+            de: self,
+            len: len,
+        })
+    }
+
+    fn visit_array<V>(&mut self, len: usize, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_seq(DeserializerArrayVisitor {
+            de: self,
+            len: len,
+        })
+    }
+
+    fn visit_tuple<V>(&mut self, len: usize, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_seq(DeserializerTupleVisitor {
+            de: self,
+            len: len,
+        })
+    }
+
+    fn visit_tuple_struct<V>(&mut self, len: usize, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_seq(DeserializerTupleStructVisitor {
+            de: self,
+            len: len,
+        })
+    }
+
+    fn visit_variant_seq<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_seq(DeserializerVariantSeqVisitor {
+            de: self,
+            len: len,
+        })
+    }
+
+    fn visit_map<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_map(DeserializerMapVisitor {
+            de: self,
+            len: len,
+        })
+    }
+
+    fn visit_struct<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_map(DeserializerStructVisitor {
+            de: self,
+            len: len,
+        })
+    }
+
+    fn visit_variant_map<V>(&mut self, len: Option<usize>, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        visitor.visit_map(DeserializerVariantMapVisitor {
+            de: self,
+            len: len,
+        })
+    }
+}
+
+impl<I> de::Deserializer for Deserializer<I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn deserialize<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.next() {
+            Some(Token::Bool(v)) => visitor.visit_bool(v),
+            Some(Token::Isize(v)) => visitor.visit_isize(v),
+            Some(Token::I8(v)) => visitor.visit_i8(v),
+            Some(Token::I16(v)) => visitor.visit_i16(v),
+            Some(Token::I32(v)) => visitor.visit_i32(v),
+            Some(Token::I64(v)) => visitor.visit_i64(v),
+            Some(Token::Usize(v)) => visitor.visit_usize(v),
+            Some(Token::U8(v)) => visitor.visit_u8(v),
+            Some(Token::U16(v)) => visitor.visit_u16(v),
+            Some(Token::U32(v)) => visitor.visit_u32(v),
+            Some(Token::U64(v)) => visitor.visit_u64(v),
+            Some(Token::F32(v)) => visitor.visit_f32(v),
+            Some(Token::F64(v)) => visitor.visit_f64(v),
+            Some(Token::Char(v)) => visitor.visit_char(v),
+            Some(Token::Str(v)) => visitor.visit_str(v),
+            Some(Token::String(v)) => visitor.visit_string(v),
+            Some(Token::Bytes(v)) => visitor.visit_bytes(v),
+            Some(Token::Option(false)) => visitor.visit_none(),
+            Some(Token::Option(true)) => visitor.visit_some(self),
+            Some(Token::Unit) => visitor.visit_unit(),
+            Some(Token::UnitStruct(name)) => visitor.visit_unit_struct(name),
+            Some(Token::SeqStart(len)) | Some(Token::TupleStructStart(_, len)) => {
+                self.visit_seq(len, visitor)
+            }
+            Some(Token::SeqArrayStart(len)) => {
+                self.visit_seq(Some(len), visitor)
+            }
+            Some(Token::MapStart(len)) | Some(Token::StructStart(_, len)) => {
+                self.visit_map(len, visitor)
+            }
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    /// Hook into `Option` deserializing so we can treat `Unit` as a
+    /// `None`, or a regular value as `Some(value)`.
+    fn deserialize_option<V>(&mut self, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::Option(false)) => {
+                self.tokens.next();
+                visitor.visit_none()
+            }
+            Some(&Token::Option(true)) => {
+                self.tokens.next();
+                visitor.visit_some(self)
+            }
+            Some(&Token::Unit) => {
+                self.tokens.next();
+                visitor.visit_none()
+            }
+            Some(_) => visitor.visit_some(self),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn deserialize_enum<V>(&mut self,
+                     name: &str,
+                     _variants: &'static [&'static str],
+                     mut visitor: V) -> Result<V::Value, Error>
+        where V: EnumVisitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::EnumStart(n)) if name == n => {
+                self.tokens.next();
+
+                visitor.visit(DeserializerVariantVisitor {
+                    de: self,
+                })
+            }
+            Some(&Token::EnumUnit(n, _))
+            | Some(&Token::EnumNewType(n, _))
+            | Some(&Token::EnumSeqStart(n, _, _))
+            | Some(&Token::EnumMapStart(n, _, _)) if name == n => {
+                visitor.visit(DeserializerVariantVisitor {
+                    de: self,
+                })
+            }
+            Some(_) => {
+                let token = self.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => { return Err(Error::EndOfStreamError); }
+        }
+    }
+
+    fn deserialize_unit_struct<V>(&mut self, name: &str, mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::UnitStruct(n)) => {
+                self.tokens.next();
+                if name == n {
+                    visitor.visit_unit()
+                } else {
+                    Err(Error::InvalidName(n))
+                }
+            }
+            Some(_) => self.deserialize(visitor),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn deserialize_newtype_struct<V>(&mut self,
+                                     name: &str,
+                                     mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::StructNewType(n)) => {
+                self.tokens.next();
+                if name == n {
+                    visitor.visit_newtype_struct(self)
+                } else {
+                    Err(Error::InvalidName(n))
+                }
+            }
+            Some(_) => self.deserialize(visitor),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn deserialize_fixed_size_array<V>(&mut self,
+                                       len: usize,
+                                       visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::SeqArrayStart(_)) => {
+                self.tokens.next();
+                self.visit_array(len, visitor)
+            }
+            Some(_) => self.deserialize(visitor),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn deserialize_tuple<V>(&mut self,
+                            len: usize,
+                            mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::Unit) => {
+                self.tokens.next();
+                visitor.visit_unit()
+            }
+            Some(&Token::UnitStruct(_)) => {
+                self.tokens.next();
+                visitor.visit_unit()
+            }
+            Some(&Token::SeqStart(_)) => {
+                self.tokens.next();
+                self.visit_seq(Some(len), visitor)
+            }
+            Some(&Token::SeqArrayStart(_)) => {
+                self.tokens.next();
+                self.visit_array(len, visitor)
+            }
+            Some(&Token::TupleStart(_)) => {
+                self.tokens.next();
+                self.visit_tuple(len, visitor)
+            }
+            Some(&Token::TupleStructStart(_, _)) => {
+                self.tokens.next();
+                self.visit_tuple_struct(len, visitor)
+            }
+            Some(_) => self.deserialize(visitor),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn deserialize_tuple_struct<V>(&mut self,
+                                   name: &str,
+                                   len: usize,
+                                   mut visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::Unit) => {
+                self.tokens.next();
+                visitor.visit_unit()
+            }
+            Some(&Token::UnitStruct(n)) => {
+                self.tokens.next();
+                if name == n {
+                    visitor.visit_unit()
+                } else {
+                    Err(Error::InvalidName(n))
+                }
+            }
+            Some(&Token::SeqStart(_)) => {
+                self.tokens.next();
+                self.visit_seq(Some(len), visitor)
+            }
+            Some(&Token::SeqArrayStart(_)) => {
+                self.tokens.next();
+                self.visit_array(len, visitor)
+            }
+            Some(&Token::TupleStart(_)) => {
+                self.tokens.next();
+                self.visit_tuple(len, visitor)
+            }
+            Some(&Token::TupleStructStart(n, _)) => {
+                self.tokens.next();
+                if name == n {
+                    self.visit_tuple_struct(len, visitor)
+                } else {
+                    Err(Error::InvalidName(n))
+                }
+            }
+            Some(_) => self.deserialize(visitor),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn deserialize_struct<V>(&mut self,
+                             name: &str,
+                             fields: &'static [&'static str],
+                             visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.tokens.peek() {
+            Some(&Token::StructStart(n, _)) => {
+                self.tokens.next();
+                if name == n {
+                    self.visit_struct(Some(fields.len()), visitor)
+                } else {
+                    Err(Error::InvalidName(n))
+                }
+            }
+            Some(&Token::MapStart(_)) => {
+                self.tokens.next();
+                self.visit_map(Some(fields.len()), visitor)
+            }
+            Some(_) => self.deserialize(visitor),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerSeqVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: Option<usize>,
+}
+
+impl<'a, I> SeqVisitor for DeserializerSeqVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit<T>(&mut self) -> Result<Option<T>, Error>
+        where T: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::SeqSep) => {
+                self.de.tokens.next();
+                self.len = self.len.map(|len| len - 1);
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::SeqEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        //assert_eq!(self.len.unwrap_or(0), 0);
+        match self.de.tokens.next() {
+            Some(Token::SeqEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len.unwrap_or(0);
+        (len, self.len)
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerArrayVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: usize,
+}
+
+impl<'a, I> SeqVisitor for DeserializerArrayVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit<T>(&mut self) -> Result<Option<T>, Error>
+        where T: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::SeqSep) => {
+                self.de.tokens.next();
+                self.len -= 1;
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::SeqEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        assert_eq!(self.len, 0);
+        match self.de.tokens.next() {
+            Some(Token::SeqEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (self.len, Some(self.len))
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerTupleVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: usize,
+}
+
+impl<'a, I> SeqVisitor for DeserializerTupleVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit<T>(&mut self) -> Result<Option<T>, Error>
+        where T: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::TupleSep) => {
+                self.de.tokens.next();
+                self.len -= 1;
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::TupleEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        assert_eq!(self.len, 0);
+        match self.de.tokens.next() {
+            Some(Token::TupleEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (self.len, Some(self.len))
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerTupleStructVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: usize,
+}
+
+impl<'a, I> SeqVisitor for DeserializerTupleStructVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit<T>(&mut self) -> Result<Option<T>, Error>
+        where T: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::TupleStructSep) => {
+                self.de.tokens.next();
+                self.len -= 1;
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::TupleStructEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        assert_eq!(self.len, 0);
+        match self.de.tokens.next() {
+            Some(Token::TupleStructEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (self.len, Some(self.len))
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerVariantSeqVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: Option<usize>,
+}
+
+impl<'a, I> SeqVisitor for DeserializerVariantSeqVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit<T>(&mut self) -> Result<Option<T>, Error>
+        where T: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::EnumSeqSep) => {
+                self.de.tokens.next();
+                self.len = self.len.map(|len| len - 1);
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::EnumSeqEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        //assert_eq!(self.len.unwrap_or(0), 0);
+        match self.de.tokens.next() {
+            Some(Token::EnumSeqEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len.unwrap_or(0);
+        (len, self.len)
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerMapVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: Option<usize>,
+}
+
+impl<'a, I> MapVisitor for DeserializerMapVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit_key<K>(&mut self) -> Result<Option<K>, Error>
+        where K: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::MapSep) => {
+                self.de.tokens.next();
+                self.len = self.len.map(|len| if len > 0 { len - 1} else { 0 });
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::MapEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn visit_value<V>(&mut self) -> Result<V, Error>
+        where V: Deserialize,
+    {
+        Ok(try!(Deserialize::deserialize(self.de)))
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        //assert_eq!(self.len.unwrap_or(0), 0);
+        match self.de.tokens.next() {
+            Some(Token::MapEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len.unwrap_or(0);
+        (len, self.len)
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerStructVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: Option<usize>,
+}
+
+impl<'a, I> MapVisitor for DeserializerStructVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit_key<K>(&mut self) -> Result<Option<K>, Error>
+        where K: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::StructSep) => {
+                self.de.tokens.next();
+                self.len = self.len.map(|len| if len > 0 { len - 1} else { 0 });
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::StructEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn visit_value<V>(&mut self) -> Result<V, Error>
+        where V: Deserialize,
+    {
+        Ok(try!(Deserialize::deserialize(self.de)))
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        //assert_eq!(self.len.unwrap_or(0), 0);
+        match self.de.tokens.next() {
+            Some(Token::StructEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len.unwrap_or(0);
+        (len, self.len)
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerVariantVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+}
+
+impl<'a, I> VariantVisitor for DeserializerVariantVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit_variant<V>(&mut self) -> Result<V, Error>
+        where V: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::EnumUnit(_, v))
+            | Some(&Token::EnumNewType(_, v))
+            | Some(&Token::EnumSeqStart(_, v, _))
+            | Some(&Token::EnumMapStart(_, v, _)) => {
+                let mut de = de::value::ValueDeserializer::<Error>::into_deserializer(v);
+                let value = try!(Deserialize::deserialize(&mut de));
+                Ok(value)
+            }
+            Some(_) => {
+                Deserialize::deserialize(self.de)
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn visit_unit(&mut self) -> Result<(), Error> {
+        match self.de.tokens.peek() {
+            Some(&Token::EnumUnit(_, _)) => {
+                self.de.tokens.next();
+                Ok(())
+            }
+            Some(_) => {
+                Deserialize::deserialize(self.de)
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn visit_newtype<T>(&mut self) -> Result<T, Self::Error>
+        where T: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::EnumNewType(_, _)) => {
+                self.de.tokens.next();
+                Deserialize::deserialize(self.de)
+            }
+            Some(_) => {
+                Deserialize::deserialize(self.de)
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn visit_tuple<V>(&mut self,
+                      len: usize,
+                      visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::EnumSeqStart(_, _, Some(enum_len))) => {
+                let token = self.de.tokens.next().unwrap();
+
+                if len == enum_len {
+                    self.de.visit_variant_seq(Some(len), visitor)
+                } else {
+                    Err(Error::UnexpectedToken(token))
+                }
+            }
+            Some(&Token::SeqStart(Some(enum_len))) => {
+                let token = self.de.tokens.next().unwrap();
+
+                if len == enum_len {
+                    self.de.visit_seq(Some(len), visitor)
+                } else {
+                    Err(Error::UnexpectedToken(token))
+                }
+            }
+            Some(_) => {
+                Deserialize::deserialize(self.de)
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn visit_struct<V>(&mut self,
+                       fields: &'static [&'static str],
+                       visitor: V) -> Result<V::Value, Error>
+        where V: Visitor,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::EnumMapStart(_, _, Some(enum_len))) => {
+                let token = self.de.tokens.next().unwrap();
+
+                if fields.len() == enum_len {
+                    self.de.visit_variant_map(Some(fields.len()), visitor)
+                } else {
+                    Err(Error::UnexpectedToken(token))
+                }
+            }
+            Some(&Token::MapStart(Some(enum_len))) => {
+                let token = self.de.tokens.next().unwrap();
+
+                if fields.len() == enum_len {
+                    self.de.visit_map(Some(fields.len()), visitor)
+                } else {
+                    Err(Error::UnexpectedToken(token))
+                }
+            }
+            Some(_) => {
+                Deserialize::deserialize(self.de)
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+struct DeserializerVariantMapVisitor<'a, I: 'a> where I: Iterator<Item=Token<'static>> {
+    de: &'a mut Deserializer<I>,
+    len: Option<usize>,
+}
+
+impl<'a, I> MapVisitor for DeserializerVariantMapVisitor<'a, I>
+    where I: Iterator<Item=Token<'static>>,
+{
+    type Error = Error;
+
+    fn visit_key<K>(&mut self) -> Result<Option<K>, Error>
+        where K: Deserialize,
+    {
+        match self.de.tokens.peek() {
+            Some(&Token::EnumMapSep) => {
+                self.de.tokens.next();
+                self.len = self.len.map(|len| if len > 0 { len - 1} else { 0 });
+                Ok(Some(try!(Deserialize::deserialize(self.de))))
+            }
+            Some(&Token::EnumMapEnd) => Ok(None),
+            Some(_) => {
+                let token = self.de.tokens.next().unwrap();
+                Err(Error::UnexpectedToken(token))
+            }
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn visit_value<V>(&mut self) -> Result<V, Error>
+        where V: Deserialize,
+    {
+        Ok(try!(Deserialize::deserialize(self.de)))
+    }
+
+    fn end(&mut self) -> Result<(), Error> {
+        //assert_eq!(self.len.unwrap_or(0), 0);
+        match self.de.tokens.next() {
+            Some(Token::EnumMapEnd) => Ok(()),
+            Some(token) => Err(Error::UnexpectedToken(token)),
+            None => Err(Error::EndOfStreamError),
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len.unwrap_or(0);
+        (len, self.len)
+    }
+}
@@ -0,0 +1,75 @@
+use std::{error, fmt};
+
+use serde::{ser, de};
+
+use token::Token;
+
+#[derive(Clone, PartialEq, Debug)]
+pub enum Error {
+    SyntaxError,
+    EndOfStreamError,
+    UnknownFieldError(String),
+    UnknownVariantError(String),
+    MissingFieldError(&'static str),
+    DuplicateFieldError(&'static str),
+    InvalidName(&'static str),
+    InvalidValue(String),
+    UnexpectedToken(Token<'static>),
+    ValueError(de::value::Error),
+}
+
+impl ser::Error for Error {
+    fn custom<T: Into<String>>(_: T) -> Error {
+        Error::SyntaxError
+    }
+
+    fn invalid_value(msg: &str) -> Error {
+        Error::InvalidValue(msg.to_owned())
+    }
+}
+
+impl de::Error for Error {
+    fn custom<T: Into<String>>(_: T) -> Error {
+        Error::SyntaxError
+    }
+
+    fn end_of_stream() -> Error {
+        Error::EndOfStreamError
+    }
+
+    fn invalid_value(msg: &str) -> Error {
+        Error::InvalidValue(msg.to_owned())
+    }
+
+    fn unknown_field(field: &str) -> Error {
+        Error::UnknownFieldError(field.to_owned())
+    }
+
+    fn unknown_variant(variant: &str) -> Error {
+        Error::UnknownVariantError(variant.to_owned())
+    }
+
+    fn missing_field(field: &'static str) -> Error {
+        Error::MissingFieldError(field)
+    }
+
+    fn duplicate_field(field: &'static str) -> Error {
+        Error::DuplicateFieldError(field)
+    }
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        formatter.write_str(format!("{:?}", self).as_ref())
+    }
+}
+
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        "Serde Error"
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        None
+    }
+}
@@ -0,0 +1,22 @@
+extern crate serde;
+
+mod assert;
+pub use assert::{
+    assert_tokens,
+    assert_ser_tokens,
+    assert_ser_tokens_error,
+    assert_de_tokens,
+    assert_de_tokens_error,
+};
+
+mod ser;
+pub use ser::Serializer;
+
+mod de;
+pub use de::Deserializer;
+
+mod token;
+pub use token::Token;
+
+mod error;
+pub use error::Error;
@@ -0,0 +1,350 @@
+use std::marker::PhantomData;
+
+use serde::ser::{
+    self,
+    MapVisitor,
+    SeqVisitor,
+    Serialize,
+};
+
+use error::Error;
+use token::Token;
+
+pub struct Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    tokens: I,
+    phantom: PhantomData<&'a Token<'a>>,
+}
+
+impl<'a, I> Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    pub fn new(tokens: I) -> Serializer<'a, I> {
+        Serializer {
+            tokens: tokens,
+            phantom: PhantomData,
+        }
+    }
+
+    pub fn next_token(&mut self) -> Option<&'a Token<'a>> {
+        self.tokens.next()
+    }
+
+    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<(), Error>
+        where V: SeqVisitor
+    {
+        while let Some(()) = try!(visitor.visit(self)) { }
+
+        assert_eq!(self.tokens.next(), Some(&Token::SeqEnd));
+
+        Ok(())
+    }
+
+    fn visit_map<V>(&mut self, mut visitor: V) -> Result<(), Error>
+        where V: MapVisitor
+    {
+        while let Some(()) = try!(visitor.visit(self)) { }
+
+        assert_eq!(self.tokens.next(), Some(&Token::MapEnd));
+
+        Ok(())
+    }
+}
+
+impl<'a, I> ser::Serializer for Serializer<'a, I>
+    where I: Iterator<Item=&'a Token<'a>>,
+{
+    type Error = Error;
+
+    fn serialize_unit(&mut self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Unit));
+        Ok(())
+    }
+
+    fn serialize_newtype_variant<T>(&mut self,
+                                name: &str,
+                                _variant_index: usize,
+                                variant: &str,
+                                value: T) -> Result<(), Error>
+        where T: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumNewType(name, variant)));
+        value.serialize(self)
+    }
+
+    fn serialize_unit_struct(&mut self, name: &str) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::UnitStruct(name)));
+        Ok(())
+    }
+
+    fn serialize_unit_variant(&mut self,
+                          name: &str,
+                          _variant_index: usize,
+                          variant: &str) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumUnit(name, variant)));
+
+        Ok(())
+    }
+
+    fn serialize_bool(&mut self, v: bool) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Bool(v)));
+        Ok(())
+    }
+
+    fn serialize_isize(&mut self, v: isize) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Isize(v)));
+        Ok(())
+    }
+
+    fn serialize_i8(&mut self, v: i8) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::I8(v)));
+        Ok(())
+    }
+
+    fn serialize_i16(&mut self, v: i16) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::I16(v)));
+        Ok(())
+    }
+
+    fn serialize_i32(&mut self, v: i32) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::I32(v)));
+        Ok(())
+    }
+
+    fn serialize_i64(&mut self, v: i64) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::I64(v)));
+        Ok(())
+    }
+
+    fn serialize_usize(&mut self, v: usize) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Usize(v)));
+        Ok(())
+    }
+
+    fn serialize_u8(&mut self, v: u8) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::U8(v)));
+        Ok(())
+    }
+
+    fn serialize_u16(&mut self, v: u16) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::U16(v)));
+        Ok(())
+    }
+
+    fn serialize_u32(&mut self, v: u32) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::U32(v)));
+        Ok(())
+    }
+
+    fn serialize_u64(&mut self, v: u64) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::U64(v)));
+        Ok(())
+    }
+
+    fn serialize_f32(&mut self, v: f32) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::F32(v)));
+        Ok(())
+    }
+
+    fn serialize_f64(&mut self, v: f64) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::F64(v)));
+        Ok(())
+    }
+
+    fn serialize_char(&mut self, v: char) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Char(v)));
+        Ok(())
+    }
+
+    fn serialize_str(&mut self, v: &str) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Str(v)));
+        Ok(())
+    }
+
+    fn serialize_none(&mut self) -> Result<(), Error> {
+        assert_eq!(self.tokens.next(), Some(&Token::Option(false)));
+        Ok(())
+    }
+
+    fn serialize_some<V>(&mut self, value: V) -> Result<(), Error>
+        where V: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::Option(true)));
+        value.serialize(self)
+    }
+
+
+    fn serialize_seq<V>(&mut self, visitor: V) -> Result<(), Error>
+        where V: SeqVisitor
+    {
+        let len = visitor.len();
+
+        assert_eq!(self.tokens.next(), Some(&Token::SeqStart(len)));
+
+        self.visit_seq(visitor)
+    }
+
+    fn serialize_fixed_size_array<V>(&mut self, visitor: V) -> Result<(), Error>
+        where V: SeqVisitor
+    {
+        let len = visitor.len().expect("arrays must have a length");
+
+        assert_eq!(self.tokens.next(), Some(&Token::SeqArrayStart(len)));
+
+        self.visit_seq(visitor)
+    }
+
+    fn serialize_seq_elt<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::SeqSep));
+        value.serialize(self)
+    }
+
+    fn serialize_tuple<V>(&mut self, mut visitor: V) -> Result<(), Error>
+        where V: SeqVisitor
+    {
+        let len = visitor.len().expect("arrays must have a length");
+
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStart(len)));
+
+        while let Some(()) = try!(visitor.visit(self)) { }
+
+        assert_eq!(self.tokens.next(), Some(&Token::TupleEnd));
+
+        Ok(())
+    }
+
+    fn serialize_tuple_elt<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleSep));
+        value.serialize(self)
+    }
+
+    fn serialize_newtype_struct<T>(&mut self,
+                               name: &'static str,
+                               value: T) -> Result<(), Error>
+        where T: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::StructNewType(name)));
+        value.serialize(self)
+    }
+
+    fn serialize_tuple_struct<V>(&mut self, name: &str, mut visitor: V) -> Result<(), Error>
+        where V: SeqVisitor
+    {
+        let len = visitor.len();
+
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStructStart(name, len)));
+
+        while let Some(()) = try!(visitor.visit(self)) { }
+
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStructEnd));
+
+        Ok(())
+    }
+
+    fn serialize_tuple_struct_elt<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::TupleStructSep));
+        value.serialize(self)
+    }
+
+    fn serialize_tuple_variant<V>(&mut self,
+                                  name: &str,
+                                  _variant_index: usize,
+                                  variant: &str,
+                                  mut visitor: V) -> Result<(), Error>
+        where V: SeqVisitor
+    {
+        let len = visitor.len();
+
+        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqStart(name, variant, len)));
+
+        while let Some(()) = try!(visitor.visit(self)) { }
+
+        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqEnd));
+
+        Ok(())
+    }
+
+    fn serialize_tuple_variant_elt<T>(&mut self, value: T) -> Result<(), Error>
+        where T: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumSeqSep));
+        value.serialize(self)
+    }
+
+    fn serialize_map<V>(&mut self, visitor: V) -> Result<(), Error>
+        where V: MapVisitor
+    {
+        let len = visitor.len();
+
+        assert_eq!(self.tokens.next(), Some(&Token::MapStart(len)));
+
+        self.visit_map(visitor)
+    }
+
+    fn serialize_map_elt<K, V>(&mut self, key: K, value: V) -> Result<(), Error>
+        where K: Serialize,
+              V: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::MapSep));
+
+        try!(key.serialize(self));
+        value.serialize(self)
+    }
+
+    fn serialize_struct<V>(&mut self, name: &str, mut visitor: V) -> Result<(), Error>
+        where V: MapVisitor
+    {
+        let len = visitor.len();
+
+        assert_eq!(self.tokens.next(), Some(&Token::StructStart(name, len)));
+
+        while let Some(()) = try!(visitor.visit(self)) { }
+
+        assert_eq!(self.tokens.next(), Some(&Token::StructEnd));
+
+        Ok(())
+    }
+
+    fn serialize_struct_elt<T>(&mut self, key: &'static str, value: T) -> Result<(), Error>
+        where T: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::StructSep));
+
+        try!(key.serialize(self));
+        value.serialize(self)
+    }
+
+    fn serialize_struct_variant<V>(&mut self,
+                                   name: &str,
+                                   _variant_index: usize,
+                                   variant: &str,
+                                   mut visitor: V) -> Result<(), Error>
+        where V: MapVisitor
+    {
+        let len = visitor.len();
+
+        assert_eq!(self.tokens.next(), Some(&Token::EnumMapStart(name, variant, len)));
+
+        while let Some(()) = try!(visitor.visit(self)) { }
+
+        assert_eq!(self.tokens.next(), Some(&Token::EnumMapEnd));
+
+        Ok(())
+    }
+
+    fn serialize_struct_variant_elt<T>(&mut self, key: &'static str, value: T) -> Result<(), Error>
+        where T: Serialize,
+    {
+        assert_eq!(self.tokens.next(), Some(&Token::EnumMapSep));
+
+        try!(key.serialize(self));
+        value.serialize(self)
+    }
+}
@@ -0,0 +1,60 @@
+#[derive(Clone, PartialEq, Debug)]
+pub enum Token<'a> {
+    Bool(bool),
+    Isize(isize),
+    I8(i8),
+    I16(i16),
+    I32(i32),
+    I64(i64),
+    Usize(usize),
+    U8(u8),
+    U16(u16),
+    U32(u32),
+    U64(u64),
+    F32(f32),
+    F64(f64),
+    Char(char),
+    Str(&'a str),
+    String(String),
+    Bytes(&'a [u8]),
+
+    Option(bool),
+
+    Unit,
+    UnitStruct(&'a str),
+
+    StructNewType(&'a str),
+
+    EnumStart(&'a str),
+    EnumUnit(&'a str, &'a str),
+    EnumNewType(&'a str, &'a str),
+
+    SeqStart(Option<usize>),
+    SeqArrayStart(usize),
+    SeqSep,
+    SeqEnd,
+
+    TupleStart(usize),
+    TupleSep,
+    TupleEnd,
+
+    TupleStructStart(&'a str, Option<usize>),
+    TupleStructSep,
+    TupleStructEnd,
+
+    MapStart(Option<usize>),
+    MapSep,
+    MapEnd,
+
+    StructStart(&'a str, Option<usize>),
+    StructSep,
+    StructEnd,
+
+    EnumSeqStart(&'a str, &'a str, Option<usize>),
+    EnumSeqSep,
+    EnumSeqEnd,
+
+    EnumMapStart(&'a str, &'a str, Option<usize>),
+    EnumMapSep,
+    EnumMapEnd,
+}