feat(headers): add LastModified header

src/header/common/last_modified.rs

@@ -0,0 +1,42 @@
+use std::fmt::{mod, Show};
+use std::str::FromStr;
+use time::Tm;
+use header::{Header, HeaderFormat};
+use super::util::{from_one_raw_str, tm_from_str};
+
+/// The `LastModified` header field.
+#[deriving(PartialEq, Clone)]
+pub struct LastModified(pub Tm);
+
+deref!(LastModified -> Tm)
+
+impl Header for LastModified {
+    fn header_name(_: Option<LastModified>) -> &'static str {
+        "Last-Modified"
+    }
+
+    fn parse_header(raw: &[Vec<u8>]) -> Option<LastModified> {
+        from_one_raw_str(raw)
+    }
+}
+
+
+impl HeaderFormat for LastModified {
+    fn fmt_header(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        let tm = **self;
+        match tm.tm_utcoff {
+            0 => tm.rfc822().fmt(fmt),
+            _ => tm.to_utc().rfc822().fmt(fmt)
+        }
+    }
+}
+
+impl FromStr for LastModified {
+    fn from_str(s: &str) -> Option<LastModified> {
+        tm_from_str(s).map(LastModified)
+    }
+}
+
+bench_header!(imf_fixdate, LastModified, { vec![b"Sun, 07 Nov 1994 08:48:37 GMT".to_vec()] })
+bench_header!(rfc_850, LastModified, { vec![b"Sunday, 06-Nov-94 08:49:37 GMT".to_vec()] })
+bench_header!(asctime, LastModified, { vec![b"Sun Nov  6 08:49:37 1994".to_vec()] })