Store time of last update as time.Time

This commit breaks the API, because LastUpdate() now returns a
time.Time object instead of an int64.

feed.go

@@ -98,7 +98,7 @@ type Feed struct {
 
 	// Last time content was fetched. Used in conjunction with CacheTimeout
 	// to ensure we don't get content too often.
-	lastupdate int64
+	lastupdate time.Time
 }
 
 // New is a helper function to stay semi-compatible with
@@ -125,8 +125,9 @@ func NewWithHandlers(cachetimeout int, enforcecachelimit bool, ch ChannelHandler
 }
 
 // This returns a timestamp of the last time the feed was updated.
-// The value is in seconds.
-func (this *Feed) LastUpdate() int64 { return this.lastupdate }
+func (this *Feed) LastUpdate() time.Time {
+	return this.lastupdate
+}
 
 // Fetch retrieves the feed's latest content if necessary.
 //
@@ -154,7 +155,7 @@ func (this *Feed) FetchClient(uri string, client *http.Client, charset xmlx.Char
 		return
 	}
 
-	this.lastupdate = time.Now().UTC().UnixNano()
+	this.lastupdate = time.Now().UTC()
 	this.Url = uri
 	doc := xmlx.New()
 
@@ -259,7 +260,8 @@ func (this *Feed) CanUpdate() bool {
 // before the feed should update.
 func (this *Feed) SecondsTillUpdate() int64 {
 	utc := time.Now().UTC()
-	return int64(this.CacheTimeout*60) - (utc.Unix() - (this.lastupdate / 1e9))
+	elapsed := utc.Sub(this.lastupdate)
+	return int64(this.CacheTimeout*60) - int64(elapsed.Seconds())
 }
 
 func (this *Feed) buildFeed(doc *xmlx.Document) (err error) {