feat(header): change Cookie to be map-like

The `Cookie` header now has 'set' and `get` methods, to treat the list of
cookies as a map.

Closes #1145

BREAKING CHANGE: The `Cookie` header is no longer a wrapper over a
  `Vec<String>`. It must be accessed via its `get` and `append` methods.

src/header/common/cookie.rs

@@ -1,7 +1,10 @@
-use header::{Header, Raw};
-use std::fmt::{self, Display};
+use std::borrow::Cow;
+use std::fmt;
 use std::str::from_utf8;
 
+use header::{Header, Raw};
+use header::internals::VecMap;
+
 /// `Cookie` header, defined in [RFC6265](http://tools.ietf.org/html/rfc6265#section-5.4)
 ///
 /// If the user agent does attach a Cookie header field to an HTTP
@@ -20,17 +23,69 @@ use std::str::from_utf8;
 /// use hyper::header::{Headers, Cookie};
 ///
 /// let mut headers = Headers::new();
+/// let mut cookie = Cookie::new();
+/// cookie.append("foo", "bar");
 ///
-/// headers.set(
-///    Cookie(vec![
-///        String::from("foo=bar")
-///    ])
-/// );
+/// assert_eq!(cookie.get("foo"), Some("bar"));
+///
+/// headers.set(cookie);
 /// ```
-#[derive(Clone, PartialEq, Debug)]
-pub struct Cookie(pub Vec<String>);
+#[derive(Clone)]
+pub struct Cookie(VecMap<Cow<'static, str>, Cow<'static, str>>);
 
-__hyper__deref!(Cookie => Vec<String>);
+impl Cookie {
+    /// Creates a new `Cookie` header.
+    pub fn new() -> Cookie {
+        Cookie(VecMap::with_capacity(0))
+    }
+
+    /// Sets a name and value for the `Cookie`.
+    ///
+    /// # Note
+    /// 
+    /// This will remove all other instances with the same name,
+    /// and insert the new value.
+    pub fn set<K, V>(&mut self, key: K, value: V)
+    where K: Into<Cow<'static, str>>,
+          V: Into<Cow<'static, str>>,
+    {
+        let key = key.into();
+        let value = value.into();
+        self.0.remove_all(&key);
+        self.0.append(key, value);
+    }
+
+    /// Append a name and value for the `Cookie`.
+    ///
+    /// # Note
+    ///
+    /// Cookies are allowed to set a name with a
+    /// a value multiple times. For example:
+    ///
+    /// ```
+    /// use hyper::header::Cookie;
+    /// let mut cookie = Cookie::new();
+    /// cookie.append("foo", "bar");
+    /// cookie.append("foo", "quux");
+    /// assert_eq!(cookie.to_string(), "foo=bar; foo=quux");
+    pub fn append<K, V>(&mut self, key: K, value: V)
+    where K: Into<Cow<'static, str>>,
+          V: Into<Cow<'static, str>>,
+    {
+        self.0.append(key.into(), value.into());
+    }
+
+    /// Get a value for the name, if it exists.
+    ///
+    /// # Note 
+    ///
+    /// Only returns the first instance found. To access
+    /// any other values associated with the name, parse
+    /// the `str` representation.
+    pub fn get(&self, key: &str) -> Option<&str> {
+        self.0.get(key).map(AsRef::as_ref)
+    }
+}
 
 impl Header for Cookie {
     fn header_name() -> &'static str {
@@ -39,16 +94,22 @@ impl Header for Cookie {
     }
 
     fn parse_header(raw: &Raw) -> ::Result<Cookie> {
-        let mut cookies = Vec::with_capacity(raw.len());
+        let mut vec_map = VecMap::with_capacity(raw.len());
         for cookies_raw in raw.iter() {
             let cookies_str = try!(from_utf8(&cookies_raw[..]));
             for cookie_str in cookies_str.split(';') {
-                cookies.push(cookie_str.trim().to_owned())
+                let mut key_val = cookie_str.splitn(2, '=');
+                let key_val = (key_val.next(), key_val.next());
+                if let (Some(key), Some(val)) = key_val {
+                    vec_map.insert(key.trim().to_owned().into(), val.trim().to_owned().into());
+                } else {
+                    return Err(::Error::Header);
+                }
             }
         }
 
-        if !cookies.is_empty() {
-            Ok(Cookie(cookies))
+        if vec_map.len() != 0 {
+            Ok(Cookie(vec_map))
         } else {
             Err(::Error::Header)
         }
@@ -59,16 +120,110 @@ impl Header for Cookie {
     }
 }
 
+impl PartialEq for Cookie {
+    fn eq(&self, other: &Cookie) -> bool {
+        if self.0.len() == other.0.len() {
+            for &(ref k, ref v) in self.0.iter() {
+                if other.get(k) != Some(v) {
+                    return false;
+                }
+            }
+            true
+        } else {
+            false
+        }
+    }
+}
+
+impl fmt::Debug for Cookie {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_map()
+            .entries(self.0.iter().map(|&(ref k, ref v)| (k, v)))
+            .finish()
+    }
+}
+
 impl fmt::Display for Cookie {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let cookies = &self.0;
-        for (i, cookie) in cookies.iter().enumerate() {
-            if i != 0 {
-                try!(f.write_str("; "));
-            }
-            try!(Display::fmt(&cookie, f));
+        let mut iter = self.0.iter();
+        if let Some(&(ref key, ref val)) = iter.next() {
+            try!(write!(f, "{}={}", key, val));
+        }
+        for &(ref key, ref val) in iter {
+            try!(write!(f, "; {}={}", key, val));
         }
         Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ::header::Header;
+    use super::Cookie;
+
+    #[test]
+    fn test_set_and_get() {
+        let mut cookie = Cookie::new();
+        cookie.append("foo", "bar");
+        cookie.append(String::from("dyn"), String::from("amic"));
+
+        assert_eq!(cookie.get("foo"), Some("bar"));
+        assert_eq!(cookie.get("dyn"), Some("amic"));
+        assert!(cookie.get("nope").is_none());
+
+        cookie.append("foo", "notbar");
+        assert_eq!(cookie.get("foo"), Some("bar"));
+
+        cookie.set("foo", "hi");
+        assert_eq!(cookie.get("foo"), Some("hi"));
+        assert_eq!(cookie.get("dyn"), Some("amic"));
+    }
+
+    #[test]
+    fn test_eq() {
+        let mut cookie = Cookie::new();
+        let mut cookie2 = Cookie::new();
+
+        // empty is equal
+        assert_eq!(cookie, cookie2);
+
+        // left has more params
+        cookie.append("foo", "bar");
+        assert!(cookie != cookie2);
+
+        // same len, different params
+        cookie2.append("bar", "foo");
+        assert!(cookie != cookie2);
+
+
+        // right has more params, and matching KV
+        cookie2.append("foo", "bar");
+        assert!(cookie != cookie2);
+
+        // same params, different order
+        cookie.append("bar", "foo");
+        assert_eq!(cookie, cookie2);
+    }
+
+    #[test]
+    fn test_parse() {
+        let mut cookie = Cookie::new();
+
+        let parsed = Cookie::parse_header(&b"foo=bar".to_vec().into()).unwrap();
+        cookie.append("foo", "bar");
+        assert_eq!(cookie, parsed);
+
+        let parsed = Cookie::parse_header(&b"foo=bar; baz=quux".to_vec().into()).unwrap();
+        cookie.append("baz", "quux");
+        assert_eq!(cookie, parsed);
+
+        let parsed = Cookie::parse_header(&b" foo  =    bar;baz= quux  ".to_vec().into()).unwrap();
+        assert_eq!(cookie, parsed);
+
+        let parsed = Cookie::parse_header(&vec![b"foo  =    bar".to_vec(),b"baz= quux  ".to_vec()].into()).unwrap();
+        assert_eq!(cookie, parsed);
+
+        Cookie::parse_header(&b"foo;bar=baz;quux".to_vec().into()).unwrap_err();
 
     }
 }