@@ -84,6 +84,7 @@ pub type ProductIdentifier = Identifier;
8484/// Jan 1970). It is a signed integer because it's the standard in Unix systems and allows easier
8585/// time difference.
8686pub type UnixTimestamp = i64 ;
87+ pub type DurationInSeconds = u64 ;
8788
8889/// Represents availability status of a price feed.
8990#[ derive(
@@ -277,22 +278,67 @@ impl PriceFeed {
277278 }
278279 }
279280
280- /// Get the "unchecked" previous price with Trading status,
281- /// along with the timestamp at which it was generated.
281+ /// Get the latest available price, along with the timestamp when it was generated.
282282///
283- /// WARNING:
284- /// We make no guarantees about the unchecked price and confidence returned by
285- /// this function: it could differ significantly from the current price.
286- /// We strongly encourage you to use `get_current_price` instead.
287- pub fn get_prev_price_unchecked ( & self ) -> ( Price , UnixTimestamp ) {
288- (
289- Price {
290- price : self . prev_price ,
291- conf : self . prev_conf ,
292- expo : self . expo ,
293- } ,
294- self . prev_publish_time ,
295- )
283+ /// This function returns the same price as `get_current_price` in the case where a price was
284+ /// available at the time this `PriceFeed` was published (`publish_time`). However, if a
285+ /// price was not available at that time, this function returns the price from the latest
286+ /// time at which the price was available. The returned price can be from arbitrarily far in
287+ /// the past; this function makes no guarantees that the returned price is recent or useful
288+ /// for any particular application.
289+ ///
290+ /// Users of this function should check the returned timestamp to ensure that the returned price
291+ /// is sufficiently recent for their application. If you are considering using this
292+ /// function, it may be safer / easier to use either `get_current_price` or
293+ /// `get_latest_available_price_within_duration`.
294+ ///
295+ /// Returns a struct containing the latest available price, confidence interval, and the
296+ /// exponent for both numbers along with the timestamp when that price was generated.
297+ pub fn get_latest_available_price_unchecked ( & self ) -> ( Price , UnixTimestamp ) {
298+ match self . status {
299+ PriceStatus :: Trading => (
300+ Price {
301+ price : self . price ,
302+ conf : self . conf ,
303+ expo : self . expo ,
304+ } ,
305+ self . publish_time ,
306+ ) ,
307+ _ => (
308+ Price {
309+ price : self . prev_price ,
310+ conf : self . prev_conf ,
311+ expo : self . expo ,
312+ } ,
313+ self . prev_publish_time ,
314+ ) ,
315+ }
316+ }
317+
318+ /// Get the latest price as long as it was updated within `duration` seconds of the
319+ /// `current_time`.
320+ ///
321+ /// This function is a sanity-checked version of `get_latest_available_price_unchecked` which is
322+ /// useful in applications that require a sufficiently-recent price. Returns `None` if the
323+ /// price wasn't updated sufficiently recently.
324+ ///
325+ /// Returns a struct containing the latest available price, confidence interval and the exponent
326+ /// for both numbers, or `None` if no price update occurred within `duration` seconds of the
327+ /// `current_time`.
328+ pub fn get_latest_available_price_within_duration (
329+ & self ,
330+ current_time : UnixTimestamp ,
331+ duration : DurationInSeconds ,
332+ ) -> Option < Price > {
333+ let ( price, publish_time) = self . get_latest_available_price_unchecked ( ) ;
334+
335+ let time_diff_abs = ( publish_time - current_time) . abs ( ) as u64 ;
336+
337+ if time_diff_abs > duration {
338+ return None ;
339+ }
340+
341+ Some ( price)
296342 }
297343}
298344#[ cfg( test) ]
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