1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110

//! This module implements some useful objects.

use std::iter;
use std::collections::HashMap;
use std::collections::hash_map;


/// `MultiDict` list entries iterator.
type MultiDictListIter<'a, T> = hash_map::Iter<'a, String, Vec<T>>;
/// `MultiDict` list values iterator.
type MultiDictListValues<'a, T> = hash_map::Values<'a, String, Vec<T>>;

/// `MultiDict` values iterator.
pub struct MultiDictValues<'a, T: 'a> {
    inner: iter::Map<MultiDictListValues<'a, T>, fn(&'a Vec<T>) -> &'a T>
}

impl<'a, T: 'a> iter::Iterator for MultiDictValues<'a, T> {
    type Item = &'a T;

    #[inline] fn next(&mut self) -> Option<&'a T> { self.inner.next() }
    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
}

/// `MultiDict` entries iterator.
pub struct MultiDictIter<'a, T: 'a> {
    inner: iter::Map<MultiDictListIter<'a, T>, for<'b, 'c> fn((&'b String, &'c Vec<T>)) -> (&'b String, &'c T)>
}

impl<'a, T: 'a> iter::Iterator for MultiDictIter<'a, T> {
    type Item = (&'a String, &'a T);

    #[inline] fn next(&mut self) -> Option<(&'a String, &'a T)> { self.inner.next() }
    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
}

/// This is used to deal with multiple values for the same key.
#[derive(Clone)]
pub struct MultiDict<T> {
    map: HashMap<String, Vec<T>>,
}

impl<T> MultiDict<T> {
    pub fn new() -> MultiDict<T> {
        MultiDict {
            map: HashMap::new(),
        }
    }

    /// Return the first value for this key.
    pub fn get(&self, key: &str) -> Option<&T> {
        match self.map.get(&key.to_string()) {
            Some(value) => Some(&value[0]),
            None => None
        }
    }

    /// Removes an existing key first and add the value.
    pub fn set(&mut self, key: &str, value: T) {
        self.map.insert(key.to_string(), vec![value]);
    }

    /// Adds a new value for the key.
    pub fn add(&mut self, key: String, value: T) {
        match self.map.remove(&key) {
            Some(mut v) => {
                v.push(value);
                self.map.insert(key, v);
            },
            None => {
                self.map.insert(key, vec![value]);
            },
        }
    }

    /// Return the list of items for a given key.
    pub fn getlist(&self, key: &str) -> Option<&Vec<T>> {
        self.map.get(&key.to_string())
    }
    
    /// An iterator of `(key, value)` pairs.
    /// The value will be first value of each key.
    pub fn iter<'a>(&'a self) -> MultiDictIter<'a, T> {
        fn first<'a, 'b, A, B>(kvpair: (&'a A, &'b Vec<B>)) -> (&'a A, &'b B) { (kvpair.0, &kvpair.1[0]) }
        let first: for<'b, 'c> fn((&'b String, &'c Vec<T>)) -> (&'b String, &'c T) = first;
        MultiDictIter { inner: self.listiter().map(first) }
    }

    /// An iterator of `(key, values)` pairs.
    pub fn listiter<'a>(&'a self) -> hash_map::Iter<'a, String, Vec<T>> {
        self.map.iter()
    }

    /// An iterator visiting all keys in arbitrary order.
    pub fn keys<'a>(&'a self) -> hash_map::Keys<'a, String, Vec<T>> {
        self.map.keys()
    }

    /// An iterator of the first value on every key's value list.
    pub fn values<'a>(&'a self) -> MultiDictValues<'a, T> {
        fn first<'a, A>(list: &'a Vec<A>) -> &'a A { &list[0] }
        let first: for<'b> fn(&'b Vec<T>) -> &'b T = first;
        MultiDictValues { inner: self.listvalues().map(first) }
    }

    /// An iterator of all values corresponding to a key.
    pub fn listvalues<'a>(&'a self) -> hash_map::Values<'a, String, Vec<T>> {
        self.map.values()
    }
}