1 //! An optional implementation of serialization/deserialization.
2 
3 extern crate serde;
4 
5 use std::fmt::{Formatter, Result as FmtResult};
6 use std::marker::PhantomData;
7 use std::hash::{BuildHasher, Hash};
8 
9 use super::LinkedHashMap;
10 
11 use self::serde::{Serialize, Serializer, Deserialize, Deserializer};
12 use self::serde::ser::SerializeMap;
13 use self::serde::de::{Visitor, MapAccess, Error};
14 
15 impl<K, V, S> Serialize for LinkedHashMap<K, V, S>
16     where K: Serialize + Eq + Hash,
17           V: Serialize,
18           S: BuildHasher
19 {
20     #[inline]
serialize<T>(&self, serializer:T) -> Result<T::Ok, T::Error> where T: Serializer,21     fn serialize<T>(&self, serializer:T) -> Result<T::Ok, T::Error>
22         where T: Serializer,
23     {
24         let mut map_serializer = try!(serializer.serialize_map(Some(self.len())));
25         for (k, v) in self {
26             try!(map_serializer.serialize_key(k));
27             try!(map_serializer.serialize_value(v));
28         }
29         map_serializer.end()
30     }
31 }
32 
33 #[derive(Debug)]
34 /// `serde::de::Visitor` for a linked hash map.
35 pub struct LinkedHashMapVisitor<K, V> {
36     marker: PhantomData<LinkedHashMap<K, V>>,
37 }
38 
39 impl<K, V> LinkedHashMapVisitor<K, V> {
40     /// Creates a new visitor for a linked hash map.
new() -> Self41     pub fn new() -> Self {
42         LinkedHashMapVisitor {
43             marker: PhantomData,
44         }
45     }
46 }
47 
48 impl<K, V> Default for LinkedHashMapVisitor<K, V> {
default() -> Self49     fn default() -> Self {
50         LinkedHashMapVisitor::new()
51     }
52 }
53 
54 impl<'de, K, V> Visitor<'de> for LinkedHashMapVisitor<K, V>
55     where K: Deserialize<'de> + Eq + Hash,
56           V: Deserialize<'de>,
57 {
58     type Value = LinkedHashMap<K, V>;
59 
expecting(&self, formatter: &mut Formatter) -> FmtResult60     fn expecting(&self, formatter: &mut Formatter) -> FmtResult {
61         write!(formatter, "a map")
62     }
63 
64     #[inline]
visit_unit<E>(self) -> Result<Self::Value, E> where E: Error,65     fn visit_unit<E>(self) -> Result<Self::Value, E>
66         where E: Error,
67     {
68         Ok(LinkedHashMap::new())
69     }
70 
71     #[inline]
visit_map<M>(self, mut map: M) -> Result<Self::Value, M::Error> where M: MapAccess<'de>,72     fn visit_map<M>(self, mut map: M) -> Result<Self::Value, M::Error>
73         where M: MapAccess<'de>,
74     {
75         let mut values = LinkedHashMap::with_capacity(map.size_hint().unwrap_or(0));
76 
77         while let Some((key, value)) = map.next_entry()? {
78             values.insert(key, value);
79         }
80 
81         Ok(values)
82     }
83 }
84 
85 impl<'de, K, V> Deserialize<'de> for LinkedHashMap<K, V>
86     where K: Deserialize<'de> + Eq + Hash,
87           V: Deserialize<'de>,
88 {
deserialize<D>(deserializer: D) -> Result<LinkedHashMap<K, V>, D::Error> where D: Deserializer<'de>,89     fn deserialize<D>(deserializer: D) -> Result<LinkedHashMap<K, V>, D::Error>
90         where D: Deserializer<'de>,
91     {
92         deserializer.deserialize_map(LinkedHashMapVisitor::new())
93     }
94 }
95