| use std::cell::RefCell; |
| use std::fmt::{self, Write}; |
| use std::str; |
| |
| use http::header::HeaderValue; |
| use time::{self, Duration}; |
| |
| // "Sun, 06 Nov 1994 08:49:37 GMT".len() |
| pub const DATE_VALUE_LENGTH: usize = 29; |
| |
| pub fn extend(dst: &mut Vec<u8>) { |
| CACHED.with(|cache| { |
| dst.extend_from_slice(cache.borrow().buffer()); |
| }) |
| } |
| |
| pub fn update() { |
| CACHED.with(|cache| { |
| cache.borrow_mut().check(); |
| }) |
| } |
| |
| pub(crate) fn update_and_header_value() -> HeaderValue { |
| CACHED.with(|cache| { |
| let mut cache = cache.borrow_mut(); |
| cache.check(); |
| HeaderValue::from_bytes(cache.buffer()) |
| .expect("Date format should be valid HeaderValue") |
| }) |
| } |
| |
| struct CachedDate { |
| bytes: [u8; DATE_VALUE_LENGTH], |
| pos: usize, |
| next_update: time::Timespec, |
| } |
| |
| thread_local!(static CACHED: RefCell<CachedDate> = RefCell::new(CachedDate::new())); |
| |
| impl CachedDate { |
| fn new() -> Self { |
| let mut cache = CachedDate { |
| bytes: [0; DATE_VALUE_LENGTH], |
| pos: 0, |
| next_update: time::Timespec::new(0, 0), |
| }; |
| cache.update(time::get_time()); |
| cache |
| } |
| |
| fn buffer(&self) -> &[u8] { |
| &self.bytes[..] |
| } |
| |
| fn check(&mut self) { |
| let now = time::get_time(); |
| if now > self.next_update { |
| self.update(now); |
| } |
| } |
| |
| fn update(&mut self, now: time::Timespec) { |
| self.pos = 0; |
| let _ = write!(self, "{}", time::at_utc(now).rfc822()); |
| debug_assert!(self.pos == DATE_VALUE_LENGTH); |
| self.next_update = now + Duration::seconds(1); |
| self.next_update.nsec = 0; |
| } |
| } |
| |
| impl fmt::Write for CachedDate { |
| fn write_str(&mut self, s: &str) -> fmt::Result { |
| let len = s.len(); |
| self.bytes[self.pos..self.pos + len].copy_from_slice(s.as_bytes()); |
| self.pos += len; |
| Ok(()) |
| } |
| } |
| |
| #[test] |
| fn test_date_len() { |
| assert_eq!(DATE_VALUE_LENGTH, "Sun, 06 Nov 1994 08:49:37 GMT".len()); |
| } |