1//! A module which exports a few traits for converting types to elements and attributes.
2
3use element::{Element, ElementBuilder};
4
5/// A struct which is used for emitting `Element`s and text nodes into an `Element` without
6/// exposing more functionality than necessary.
7pub struct ElementEmitter<'a>(&'a mut Element);
8
9impl<'a> ElementEmitter<'a> {
10 /// Creates a new `ElementEmitter`.
11 pub fn new(root: &'a mut Element) -> ElementEmitter<'a> {
12 ElementEmitter(root)
13 }
14
15 /// Appends an `Element` to the target.
16 pub fn append_child(&mut self, element: Element) {
17 self.0.append_child(element);
18 }
19
20 /// Appends a text node to the target.
21 pub fn append_text_node(&mut self, text: String) {
22 self.0.append_text_node(text);
23 }
24}
25
26/// A trait for types which can be converted to one or multiple `Element`s.
27pub trait IntoElements {
28 /// Emits this as a sequence of text nodes and `Element`s.
29 fn into_elements(self, emitter: &mut ElementEmitter);
30}
31
32impl<T: IntoElements> IntoElements for Vec<T> {
33 fn into_elements(self, emitter: &mut ElementEmitter) {
34 for elem in self {
35 elem.into_elements(emitter);
36 }
37 }
38}
39
40impl<'a, T: IntoElements + Clone> IntoElements for &'a [T] {
41 fn into_elements(self, emitter: &mut ElementEmitter) {
42 self.to_vec().into_elements(emitter);
43 }
44}
45
46impl<T: IntoElements> IntoElements for Option<T> {
47 fn into_elements(self, emitter: &mut ElementEmitter) {
48 if let Some(e) = self {
49 e.into_elements(emitter);
50 }
51 }
52}
53
54impl<T> IntoElements for T where T: Into<Element> {
55 fn into_elements(self, emitter: &mut ElementEmitter) {
56 emitter.append_child(self.into());
57 }
58}
59
60impl IntoElements for ElementBuilder {
61 fn into_elements(self, emitter: &mut ElementEmitter) {
62 emitter.append_child(self.build());
63 }
64}
65
66impl IntoElements for String {
67 fn into_elements(self, emitter: &mut ElementEmitter) {
68 emitter.append_text_node(self);
69 }
70}
71
72impl<'a> IntoElements for &'a String {
73 fn into_elements(self, emitter: &mut ElementEmitter) {
74 emitter.append_text_node(self.to_owned());
75 }
76}
77
78impl<'a> IntoElements for &'a str {
79 fn into_elements(self, emitter: &mut ElementEmitter) {
80 emitter.append_text_node(self.to_owned());
81 }
82}
83
84/// A trait for types which can be converted to an attribute value.
85pub trait IntoAttributeValue {
86 /// Turns this into an attribute string, or None if it shouldn't be added.
87 fn into_attribute_value(self) -> Option<String>;
88}
89
90macro_rules! impl_into_attribute_value {
91 ($t:ty) => {
92 impl IntoAttributeValue for $t {
93 fn into_attribute_value(self) -> Option<String> {
94 Some(format!("{}", self))
95 }
96 }
97 }
98}
99
100macro_rules! impl_into_attribute_values {
101 ($($t:ty),*) => {
102 $(impl_into_attribute_value!($t);)*
103 }
104}
105
106impl_into_attribute_values!(usize, u64, u32, u16, u8, isize, i64, i32, i16, i8, ::std::net::IpAddr);
107
108impl IntoAttributeValue for String {
109 fn into_attribute_value(self) -> Option<String> {
110 Some(self)
111 }
112}
113
114impl<'a> IntoAttributeValue for &'a String {
115 fn into_attribute_value(self) -> Option<String> {
116 Some(self.to_owned())
117 }
118}
119
120impl<'a> IntoAttributeValue for &'a str {
121 fn into_attribute_value(self) -> Option<String> {
122 Some(self.to_owned())
123 }
124}
125
126impl<T: IntoAttributeValue> IntoAttributeValue for Option<T> {
127 fn into_attribute_value(self) -> Option<String> {
128 self.and_then(|t| t.into_attribute_value())
129 }
130}
131
132#[cfg(test)]
133mod tests {
134 use super::IntoAttributeValue;
135 use std::net::IpAddr;
136 use std::str::FromStr;
137
138 #[test]
139 fn test_into_attribute_value_on_ints() {
140 assert_eq!(16u8.into_attribute_value().unwrap() , "16");
141 assert_eq!(17u16.into_attribute_value().unwrap() , "17");
142 assert_eq!(18u32.into_attribute_value().unwrap() , "18");
143 assert_eq!(19u64.into_attribute_value().unwrap() , "19");
144 assert_eq!( 16i8.into_attribute_value().unwrap() , "16");
145 assert_eq!((-17i16).into_attribute_value().unwrap(), "-17");
146 assert_eq!( 18i32.into_attribute_value().unwrap(), "18");
147 assert_eq!((-19i64).into_attribute_value().unwrap(), "-19");
148 assert_eq!(IpAddr::from_str("127.000.0.1").unwrap().into_attribute_value().unwrap(), "127.0.0.1");
149 }
150}