refactor(header): make Quality an opaque struct

This makes the `u16` in `Quality` private, since it only has a valid
range of 0-1000, and can't be enforced in public. The `q` function now
allows both `f32`s and `u16`s to construct a `Quality`.

BREAKING CHANGE: Any use of `Quality(num)` should change to `q(num)`.

src/header/common/accept.rs

@@ -53,7 +53,7 @@ header! {
     /// );
     /// ```
     /// ```
-    /// use hyper::header::{Headers, Accept, QualityItem, Quality, qitem};
+    /// use hyper::header::{Headers, Accept, QualityItem, q, qitem};
     /// use hyper::mime::{Mime, TopLevel, SubLevel};
     ///
     /// let mut headers = Headers::new();
@@ -64,11 +64,11 @@ header! {
     ///         qitem(Mime(TopLevel::Application,
     ///                    SubLevel::Ext("xhtml+xml".to_owned()), vec![])),
     ///         QualityItem::new(Mime(TopLevel::Application, SubLevel::Xml, vec![]),
-    ///                          Quality(900)),
+    ///                          q(900)),
     ///                          qitem(Mime(TopLevel::Image,
     ///                                     SubLevel::Ext("webp".to_owned()), vec![])),
     ///                          QualityItem::new(Mime(TopLevel::Star, SubLevel::Star, vec![]),
-    ///                                           Quality(800))
+    ///                                           q(800))
     ///     ])
     /// );
     /// ```
@@ -85,18 +85,18 @@ header! {
         //    test1,
         //    vec![b"audio/*; q=0.2, audio/basic"],
         //    Some(HeaderField(vec![
-        //        QualityItem::new(Mime(TopLevel::Audio, SubLevel::Star, vec![]), Quality(200)),
+        //        QualityItem::new(Mime(TopLevel::Audio, SubLevel::Star, vec![]), q(200)),
         //        qitem(Mime(TopLevel::Audio, SubLevel::Ext("basic".to_owned()), vec![])),
         //        ])));
         test_header!(
             test2,
             vec![b"text/plain; q=0.5, text/html, text/x-dvi; q=0.8, text/x-c"],
             Some(HeaderField(vec![
-                QualityItem::new(Mime(TopLevel::Text, SubLevel::Plain, vec![]), Quality(500)),
+                QualityItem::new(Mime(TopLevel::Text, SubLevel::Plain, vec![]), q(500)),
                 qitem(Mime(TopLevel::Text, SubLevel::Html, vec![])),
                 QualityItem::new(
                     Mime(TopLevel::Text, SubLevel::Ext("x-dvi".to_owned()), vec![]),
-                    Quality(800)),
+                    q(800)),
                 qitem(Mime(TopLevel::Text, SubLevel::Ext("x-c".to_owned()), vec![])),
                 ])));
         // Custom tests
@@ -112,7 +112,7 @@ header! {
             Some(Accept(vec![
                 QualityItem::new(Mime(TopLevel::Text,
                     SubLevel::Plain, vec![(Attr::Charset, Value::Utf8)]),
-                    Quality(500)),
+                    q(500)),
             ])));
 
         #[test]

src/header/common/accept_charset.rs

@@ -29,13 +29,13 @@ header! {
     /// );
     /// ```
     /// ```
-    /// use hyper::header::{Headers, AcceptCharset, Charset, Quality, QualityItem};
+    /// use hyper::header::{Headers, AcceptCharset, Charset, q, QualityItem};
     ///
     /// let mut headers = Headers::new();
     /// headers.set(
     ///     AcceptCharset(vec![
-    ///         QualityItem::new(Charset::Us_Ascii, Quality(900)),
-    ///         QualityItem::new(Charset::Iso_8859_10, Quality(200)),
+    ///         QualityItem::new(Charset::Us_Ascii, q(900)),
+    ///         QualityItem::new(Charset::Iso_8859_10, q(200)),
     ///     ])
     /// );
     /// ```

src/header/common/accept_encoding.rs

@@ -45,14 +45,14 @@ header! {
     /// );
     /// ```
     /// ```
-    /// use hyper::header::{Headers, AcceptEncoding, Encoding, QualityItem, Quality, qitem};
+    /// use hyper::header::{Headers, AcceptEncoding, Encoding, QualityItem, q, qitem};
     ///
     /// let mut headers = Headers::new();
     /// headers.set(
     ///     AcceptEncoding(vec![
     ///         qitem(Encoding::Chunked),
-    ///         QualityItem::new(Encoding::Gzip, Quality(600)),
-    ///         QualityItem::new(Encoding::EncodingExt("*".to_owned()), Quality(0)),
+    ///         QualityItem::new(Encoding::Gzip, q(600)),
+    ///         QualityItem::new(Encoding::EncodingExt("*".to_owned()), q(0)),
     ///     ])
     /// );
     /// ```

src/header/common/accept_language.rs

@@ -36,15 +36,15 @@ header! {
     /// ```
     /// # extern crate hyper;
     /// # #[macro_use] extern crate language_tags;
-    /// # use hyper::header::{Headers, AcceptLanguage, QualityItem, Quality, qitem};
+    /// # use hyper::header::{Headers, AcceptLanguage, QualityItem, q, qitem};
     /// #
     /// # fn main() {
     /// let mut headers = Headers::new();
     /// headers.set(
     ///     AcceptLanguage(vec![
     ///         qitem(langtag!(da)),
-    ///         QualityItem::new(langtag!(en;;;GB), Quality(800)),
-    ///         QualityItem::new(langtag!(en), Quality(700)),
+    ///         QualityItem::new(langtag!(en;;;GB), q(800)),
+    ///         QualityItem::new(langtag!(en), q(700)),
     ///     ])
     /// );
     /// # }
@@ -59,7 +59,7 @@ header! {
             test2, vec![b"en-US, en; q=0.5, fr"],
             Some(AcceptLanguage(vec![
                 qitem("en-US".parse().unwrap()),
-                QualityItem::new("en".parse().unwrap(), Quality(500)),
+                QualityItem::new("en".parse().unwrap(), q(500)),
                 qitem("fr".parse().unwrap()),
         ])));
     }

src/header/common/te.rs

@@ -45,14 +45,14 @@ header! {
     /// );
     /// ```
     /// ```
-    /// use hyper::header::{Headers, TE, Encoding, QualityItem, Quality, qitem};
+    /// use hyper::header::{Headers, TE, Encoding, QualityItem, q, qitem};
     ///
     /// let mut headers = Headers::new();
     /// headers.set(
     ///     TE(vec![
     ///         qitem(Encoding::Trailers),
-    ///         QualityItem::new(Encoding::Gzip, Quality(600)),
-    ///         QualityItem::new(Encoding::EncodingExt("*".to_owned()), Quality(0)),
+    ///         QualityItem::new(Encoding::Gzip, q(600)),
+    ///         QualityItem::new(Encoding::EncodingExt("*".to_owned()), q(0)),
     ///     ])
     /// );
     /// ```