From 35786442f515ae32f130dc15472a481cf0376492 Mon Sep 17 00:00:00 2001
From: Erick Tryzelaar <erick.tryzelaar@gmail.com>
Date: Fri, 12 Sep 2014 07:55:28 -0700
Subject: [PATCH] add two deserialization variations

---
 serde2/src/de.rs       |  94 ++++++++++++
 serde2/src/de2.rs      | 335 +++++++++++++++++++++++++++++++++++++++++
 serde2/src/json/mod.rs |   1 +
 3 files changed, 430 insertions(+)
 create mode 100644 serde2/src/de.rs
 create mode 100644 serde2/src/de2.rs

diff --git a/serde2/src/de.rs b/serde2/src/de.rs
new file mode 100644
index 00000000..0753fc33
--- /dev/null
+++ b/serde2/src/de.rs
@@ -0,0 +1,94 @@
+pub trait Deserialize<D, E> {
+    fn deserialize(state: &mut D) -> Result<Self, E>;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+pub trait Deserializer<D, R> {
+    fn deserialize<T: Deserialize<D, R>>(&mut self) -> R;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+pub trait Visitor<D, R> {
+    fn visit(&mut self, state: &mut S) -> Option<R>;
+
+    #[inline]
+    fn size_hint(&self) -> (uint, Option<uint>) {
+        (0, None)
+    }
+}
+
+pub trait SeqVisitor {
+
+}
+
+pub trait VisitorState<E> {
+    fn syntax_error
+
+
+    fn visit_int(&mut self) -> Result<int, E> {
+
+    }
+
+    fn visit_seq<Iter: FromIterator>(&mut self, ) -> Iter
+
+}
+
+
+
+
+
+
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+
+impl<D: VisitorState<E>, E> Deserialize<D, E> for int {
+    #[inline]
+    fn deserialize(state: &mut D) -> Result<int, E> {
+        state.visit_int()
+    }
+}
+
+
+impl<
+    T: Deserialize<D, E>,
+    D: VisitorState<E>,
+    E
+> Deserialize<D, E> for Vec<T> {
+    #[inline]
+    fn deserialize(state: &mut D) -> Result<int, E> {
+        struct SeqVisitor {
+
+        }
+
+        impl SeqVisitor {
+            fn visit_seq<V: Visitor<Self>>(len: uint, visitor: V) {
+                let mut value = Vec::with_capacity(len);
+
+                loop {
+                    match visitor.visit(self, &mut value) {
+                        Some(()) => { }
+                        None => { break; }
+                    }
+                }
+
+                value
+            }
+
+            fn visit_seq_elt<
+                T: S
+            >(&mut self, value: &mut Vec<T>) {
+                let v = Deserialize
+                value.push(
+            }
+        }
+
+        let v = Vec::new();
+        state.visit_seq()
+    }
+}
diff --git a/serde2/src/de2.rs b/serde2/src/de2.rs
new file mode 100644
index 00000000..a6b4dead
--- /dev/null
+++ b/serde2/src/de2.rs
@@ -0,0 +1,335 @@
+use std::collections::HashMap;
+use std::hash::Hash;
+
+///////////////////////////////////////////////////////////////////////////////
+
+trait Deserialize<S, E> {
+    fn deserialize(state: &mut S) -> Result<Self, E>;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+trait VisitorState<E> {
+    fn visit_int(&mut self) -> Result<int, E>;
+
+    fn visit_string(&mut self) -> Result<String, E>;
+
+    fn visit_seq<
+        C: Deserialize<Self, E>,
+        V: Visitor<C, Self, E>
+    >(&mut self) -> Result<C, E>;
+
+    fn visit_map<
+        C: Deserialize<Self, E>,
+        V: Visitor<C, Self, E>
+    >(&mut self) -> Result<C, E>;
+}
+
+trait Visitor<C, S, E> {
+    fn new(len: uint) -> Self;
+
+    fn visit(&mut self, state: &mut S) -> Result<(), E>;
+
+    fn unwrap(self) -> Result<C, E>;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+impl<S: VisitorState<E>, E> Deserialize<S, E> for int {
+    fn deserialize(state: &mut S) -> Result<int, E> {
+        state.visit_int()
+    }
+}
+
+impl<S: VisitorState<E>, E> Deserialize<S, E> for String {
+    fn deserialize(state: &mut S) -> Result<String, E> {
+        state.visit_string()
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+impl<
+    T: Deserialize<S, E>,
+    S: VisitorState<E>,
+    E
+> Deserialize<S, E> for Vec<T> {
+    fn deserialize(state: &mut S) -> Result<Vec<T>, E> {
+        struct Visitor<T> {
+            value: Vec<T>,
+        }
+
+        impl<
+            T: Deserialize<S, E>,
+            S: VisitorState<E>,
+            E
+        > ::Visitor<Vec<T>, S, E> for Visitor<T> {
+            fn new(len: uint) -> Visitor<T> {
+                Visitor {
+                    value: Vec::with_capacity(len),
+                }
+            }
+
+            fn visit(&mut self, state: &mut S) -> Result<(), E> {
+                let value = try!(Deserialize::deserialize(state));
+                self.value.push(value);
+                Ok(())
+            }
+
+            fn unwrap(self) -> Result<Vec<T>, E> {
+                Ok(self.value)
+            }
+        }
+
+        state.visit_seq::<Vec<T>, Visitor<T>>()
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+impl<
+    T0: Deserialize<S, E>,
+    T1: Deserialize<S, E>,
+    S: VisitorState<E>,
+    E
+> Deserialize<S, E> for (T0, T1) {
+    fn deserialize(state: &mut S) -> Result<(T0, T1), E> {
+        struct Visitor<T0, T1> {
+            state: uint,
+            t0: Option<T0>,
+            t1: Option<T1>,
+        }
+
+        impl<
+            T0: Deserialize<S, E>,
+            T1: Deserialize<S, E>,
+            S,
+            E
+        > ::Visitor<(T0, T1), S, E> for Visitor<T0, T1> {
+            fn new(_: uint) -> Visitor<T0, T1> {
+                Visitor {
+                    state: 0,
+                    t0: None,
+                    t1: None,
+                }
+            }
+
+            fn visit(&mut self, state: &mut S) -> Result<(), E> {
+                match self.state {
+                    0 => {
+                        self.state += 1;
+                        self.t0 = Some(try!(Deserialize::deserialize(state)));
+                    }
+                    1 => {
+                        self.state += 1;
+                        self.t1 = Some(try!(Deserialize::deserialize(state)));
+                    }
+                    _ => fail!()
+                }
+
+                Ok(())
+            }
+
+            fn unwrap(self) -> Result<(T0, T1), E> {
+                let t0 = match self.t0 {
+                    Some(t0) => t0,
+                    None => { fail!(); }
+                };
+
+                let t1 = match self.t1 {
+                    Some(t1) => t1,
+                    None => { fail!(); }
+                };
+
+                Ok((t0, t1))
+            }
+        }
+
+        state.visit_seq::<(T0, T1), Visitor<T0, T1>>()
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+impl<
+    K: Deserialize<S, E> + Eq + Hash,
+    V: Deserialize<S, E>,
+    S: VisitorState<E>,
+    E
+> Deserialize<S, E> for HashMap<K, V> {
+    fn deserialize(state: &mut S) -> Result<HashMap<K, V>, E> {
+        struct Visitor<K, V> {
+            value: HashMap<K, V>,
+        }
+
+        impl<
+            K: Deserialize<S, E> + Eq + Hash,
+            V: Deserialize<S, E>,
+            S: VisitorState<E>,
+            E
+        > ::Visitor<HashMap<K, V>, S, E> for Visitor<K, V> {
+            fn new(len: uint) -> Visitor<K, V> {
+                Visitor {
+                    value: HashMap::with_capacity(len),
+                }
+            }
+
+            fn visit(&mut self, state: &mut S) -> Result<(), E> {
+                let key = try!(Deserialize::deserialize(state));
+                let value = try!(Deserialize::deserialize(state));
+                self.value.insert(key, value);
+                Ok(())
+            }
+
+            fn unwrap(self) -> Result<HashMap<K, V>, E> {
+                Ok(self.value)
+            }
+        }
+
+        state.visit_map::<HashMap<K, V>, Visitor<K, V>>()
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+trait Deserializer<S, E> {
+    fn deserialize<T: Deserialize<S, E>>(&mut self) -> Result<T, E>;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+enum Token {
+    Int(int),
+    String(String),
+    SeqStart(uint),
+    MapStart(uint),
+    End,
+}
+
+struct MyDeserializerState<Iter> {
+    tokens: Iter,
+    peeked: Option<Token>,
+}
+
+impl<Iter: Iterator<Token>> MyDeserializerState<Iter> {
+    fn new(tokens: Iter) -> MyDeserializerState<Iter> {
+        MyDeserializerState {
+            tokens: tokens,
+            peeked: None,
+        }
+    }
+
+    fn next(&mut self) -> Option<Token> {
+        match self.peeked.take() {
+            Some(token) => { return Some(token); }
+            None => { }
+        }
+
+        self.tokens.next()
+    }
+}
+
+impl<Iter: Iterator<Token>> VisitorState<()> for MyDeserializerState<Iter> {
+    fn visit_int(&mut self) -> Result<int, ()> {
+        match self.next() {
+            Some(Int(v)) => Ok(v),
+            _ => Err(())
+        }
+    }
+
+    fn visit_string(&mut self) -> Result<String, ()> {
+        match self.next() {
+            Some(String(v)) => Ok(v),
+            _ => Err(())
+        }
+    }
+
+    fn visit_seq<
+        T: Deserialize<MyDeserializerState<Iter>, ()>,
+        V: Visitor<T, MyDeserializerState<Iter>, ()>
+    >(&mut self) -> Result<T, ()> {
+        let len = match self.next() {
+            Some(SeqStart(len)) => len,
+            _ => { return Err(()); }
+        };
+
+        let mut visitor: V = Visitor::new(len);
+
+        loop {
+            match self.next() {
+                Some(End) => { break; }
+                Some(token) => {
+                    self.peeked = Some(token);
+                    try!(visitor.visit(self));
+                }
+                _ => { return Err(()); }
+            }
+        }
+
+        visitor.unwrap()
+    }
+
+    fn visit_map<
+        T: Deserialize<MyDeserializerState<Iter>, ()>,
+        V: Visitor<T, MyDeserializerState<Iter>, ()>
+    >(&mut self) -> Result<T, ()> {
+        let len = match self.next() {
+            Some(MapStart(len)) => len,
+            _ => { return Err(()); }
+        };
+
+        let mut visitor: V = Visitor::new(len);
+
+        loop {
+            match self.next() {
+                Some(End) => { break; }
+                Some(token) => {
+                    self.peeked = Some(token);
+                    try!(visitor.visit(self));
+                }
+                _ => { return Err(()); }
+            }
+        }
+
+        visitor.unwrap()
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+fn main() {
+    let tokens = vec!(
+        SeqStart(2),
+        Int(1),
+        Int(2),
+        End
+    );
+    let mut state = MyDeserializerState::new(tokens.move_iter());
+
+    let v: Result<Vec<int>, ()> = Deserialize::deserialize(&mut state);
+    println!("{}", v);
+
+    let tokens = vec!(
+        SeqStart(2),
+        Int(1),
+        Int(2),
+        End
+    );
+    let mut state = MyDeserializerState::new(tokens.move_iter());
+
+    let v: Result<(int, int), ()> = Deserialize::deserialize(&mut state);
+    println!("{}", v);
+
+    let tokens = vec!(
+        MapStart(2),
+        String("a".to_string()),
+        Int(1),
+        String("b".to_string()),
+        Int(2),
+        End
+    );
+    let mut state = MyDeserializerState::new(tokens.move_iter());
+
+    let v: Result<HashMap<String, int>, ()> = Deserialize::deserialize(&mut state);
+    println!("{}", v);
+}
diff --git a/serde2/src/json/mod.rs b/serde2/src/json/mod.rs
index 88ab1c5e..d67c8c5b 100644
--- a/serde2/src/json/mod.rs
+++ b/serde2/src/json/mod.rs
@@ -3,3 +3,4 @@ pub use self::ser::{to_vec, to_string};
 pub use self::ser::escape_str;
 
 pub mod ser;
+pub mod de;