improve cache handler, embracing #2210 too

cache/entry/entry.go

@@ -3,15 +3,14 @@ package entry
 import (
 	"time"
 
-	"github.com/kataras/iris/v12/cache/cfg"
+	"github.com/kataras/iris/v12/core/memstore"
 )
 
 // Entry is the cache entry
 // contains the expiration datetime and the response
 type Entry struct {
-	life time.Duration
 	// ExpiresAt is the time which this cache will not be available
-	expiresAt time.Time
+	lifeTime *memstore.LifeTime
 
 	// when `Reset` this value is reseting to time.Now(),
 	// it's used to send the "Last-Modified" header,
@@ -25,104 +24,30 @@ type Entry struct {
 	// of store map
 }
 
-// NewEntry returns a new cache entry
-// it doesn't sets the expiresAt & the response
-// because these are setting each time on Reset
-func NewEntry(duration time.Duration) *Entry {
-	// if given duration is not <=0 (which means finds from the headers)
-	// then we should check for the MinimumCacheDuration here
-	if duration >= 0 && duration < cfg.MinimumCacheDuration {
-		duration = cfg.MinimumCacheDuration
-	}
-
-	return &Entry{
-		life:     duration,
-		response: &Response{},
-	}
+// reset called each time a new entry is acquired from the pool.
+func (e *Entry) reset(lt *memstore.LifeTime, r *Response) {
+	e.response = r
+	e.LastModified = lt.Begun
 }
 
-// Response gets the cache response contents
-// if it's valid returns them with a true value
-// otherwise returns nil, false
-func (e *Entry) Response() (*Response, bool) {
-	if !e.valid() {
-		// it has been expired
-		return nil, false
-	}
-	return e.response, true
+// Response returns the cached response as it's.
+func (e *Entry) Response() *Response {
+	return e.response
 }
 
-// valid returns true if this entry's response is still valid
-// or false if the expiration time passed
-func (e *Entry) valid() bool {
-	return !time.Now().After(e.expiresAt)
-}
+// // Response gets the cache response contents
+// // if it's valid returns them with a true value
+// // otherwise returns nil, false
+// func (e *Entry) Response() (*Response, bool) {
+// 	if !e.isValid() {
+// 		// it has been expired
+// 		return nil, false
+// 	}
+// 	return e.response, true
+// }
 
-// LifeChanger is the function which returns
-// a duration which will be compared with the current
-// entry's (cache life)  duration
-// and execute the LifeChanger func
-// to set the new life time
-type LifeChanger func() time.Duration
-
-// ChangeLifetime modifies the life field
-// which is the life duration of the cached response
-// of this cache entry
-//
-// useful when we find a max-age header from the handler
-func (e *Entry) ChangeLifetime(fdur LifeChanger) {
-	if e.life < cfg.MinimumCacheDuration {
-		newLifetime := fdur()
-		if newLifetime > e.life {
-			e.life = newLifetime
-		} else {
-			// if even the new lifetime is less than MinimumCacheDuration
-			// then change set it explicitly here
-			e.life = cfg.MinimumCacheDuration
-		}
-	}
-}
-
-// CopyHeaders clones headers "src" to "dst" .
-func CopyHeaders(dst map[string][]string, src map[string][]string) {
-	if dst == nil || src == nil {
-		return
-	}
-
-	for k, vv := range src {
-		v := make([]string, len(vv))
-		copy(v, vv)
-		dst[k] = v
-	}
-}
-
-// Reset called each time the entry is expired
-// and the handler calls this after the original handler executed
-// to re-set the response with the new handler's content result
-func (e *Entry) Reset(statusCode int, headers map[string][]string,
-	body []byte, lifeChanger LifeChanger) {
-	if e.response == nil {
-		e.response = &Response{}
-	}
-	if statusCode > 0 {
-		e.response.statusCode = statusCode
-	}
-
-	if len(headers) > 0 {
-		newHeaders := make(map[string][]string, len(headers))
-		CopyHeaders(newHeaders, headers)
-		e.response.headers = newHeaders
-	}
-
-	e.response.body = make([]byte, len(body))
-	copy(e.response.body, body)
-	// check if a given life changer provided
-	// and if it does then execute the change life time
-	if lifeChanger != nil {
-		e.ChangeLifetime(lifeChanger)
-	}
-
-	now := time.Now()
-	e.expiresAt = now.Add(e.life)
-	e.LastModified = now
-}
+// // isValid reports whether this entry's response is still valid or expired.
+// // If the entry exists in the store then it should be valid anyways.
+// func (e *Entry) isValid() bool {
+// 	return !e.lifeTime.HasExpired()
+// }