Fix incorrect key in concurrent benchmarks

Fixes #111

CONTRIBUTORS

@@ -6,3 +6,4 @@ code was contributed.)
 Dustin Sallings <dustin@spy.net>
 Jason Mooberry <jasonmoo@me.com>
 Sergey Shepelev <temotor@gmail.com>
+Alex Edwards <ajmedwards@gmail.com>

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2012-2015 Patrick Mylund Nielsen and the go-cache contributors
+Copyright (c) 2012-2019 Patrick Mylund Nielsen and the go-cache contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -20,86 +20,62 @@ one) to recover from downtime quickly. (See the docs for `NewFrom()` for caveats
 ### Usage
 
 ```go
-	import (
+import (
-		"fmt"
+	"fmt"
-		"github.com/patrickmn/go-cache"
+	"github.com/patrickmn/go-cache"
-		"time"
+	"time"
-	)
+)
 
-	func main() {
+func main() {
+	// Create a cache with a default expiration time of 5 minutes, and which
+	// purges expired items every 10 minutes
+	c := cache.New(5*time.Minute, 10*time.Minute)
 
-		// Create a cache with a default expiration time of 5 minutes, and which
+	// Set the value of the key "foo" to "bar", with the default expiration time
-		// purges expired items every 30 seconds
+	c.Set("foo", "bar", cache.DefaultExpiration)
-		c := cache.New(5*time.Minute, 30*time.Second)
 
-		// Set the value of the key "foo" to "bar", with the default expiration time
+	// Set the value of the key "baz" to 42, with no expiration time
-		c.Set("foo", "bar", cache.DefaultExpiration)
+	// (the item won't be removed until it is re-set, or removed using
-
+	// c.Delete("baz")
-		// Set the value of the key "baz" to 42, with no expiration time
+	c.Set("baz", 42, cache.NoExpiration)
-		// (the item won't be removed until it is re-set, or removed using
-		// c.Delete("baz")
-		c.Set("baz", 42, cache.NoExpiration)
-
-		// Get the string associated with the key "foo" from the cache
-		foo, found := c.Get("foo")
-		if found {
-			fmt.Println(foo)
-		}
-
-		// Since Go is statically typed, and cache values can be anything, type
-		// assertion is needed when values are being passed to functions that don't
-		// take arbitrary types, (i.e. interface{}). The simplest way to do this for
-		// values which will only be used once--e.g. for passing to another
-		// function--is:
-		foo, found := c.Get("foo")
-		if found {
-			MyFunction(foo.(string))
-		}
-
-		// This gets tedious if the value is used several times in the same function.
-		// You might do either of the following instead:
-		if x, found := c.Get("foo"); found {
-			foo := x.(string)
-			// ...
-		}
-		// or
-		var foo string
-		if x, found := c.Get("foo"); found {
-			foo = x.(string)
-		}
-		// ...
-		// foo can then be passed around freely as a string
-
-		// Want performance? Store pointers!
-		c.Set("foo", &MyStruct, cache.DefaultExpiration)
-		if x, found := c.Get("foo"); found {
-			foo := x.(*MyStruct)
-			// ...
-		}
-
-		// If you store a reference type like a pointer, slice, map or channel, you
-		// do not need to run Set if you modify the underlying data. The cached
-		// reference points to the same memory, so if you modify a struct whose
-		// pointer you've stored in the cache, retrieving that pointer with Get will
-		// point you to the same data:
-		foo := &MyStruct{Num: 1}
-		c.Set("foo", foo, cache.DefaultExpiration)
-		// ...
-		x, _ := c.Get("foo")
-		foo := x.(*MyStruct)
-		fmt.Println(foo.Num)
-		// ...
-		foo.Num++
-		// ...
-		x, _ := c.Get("foo")
-		foo := x.(*MyStruct)
-		foo.Println(foo.Num)
-
-		// will print:
-		// 1
-		// 2
 
+	// Get the string associated with the key "foo" from the cache
+	foo, found := c.Get("foo")
+	if found {
+		fmt.Println(foo)
 	}
+
+	// Since Go is statically typed, and cache values can be anything, type
+	// assertion is needed when values are being passed to functions that don't
+	// take arbitrary types, (i.e. interface{}). The simplest way to do this for
+	// values which will only be used once--e.g. for passing to another
+	// function--is:
+	foo, found := c.Get("foo")
+	if found {
+		MyFunction(foo.(string))
+	}
+
+	// This gets tedious if the value is used several times in the same function.
+	// You might do either of the following instead:
+	if x, found := c.Get("foo"); found {
+		foo := x.(string)
+		// ...
+	}
+	// or
+	var foo string
+	if x, found := c.Get("foo"); found {
+		foo = x.(string)
+	}
+	// ...
+	// foo can then be passed around freely as a string
+
+	// Want performance? Store pointers!
+	c.Set("foo", &MyStruct, cache.DefaultExpiration)
+	if x, found := c.Get("foo"); found {
+		foo := x.(*MyStruct)
+			// ...
+	}
+}
 ```
 
 ### Reference

cache.go

@@ -81,6 +81,12 @@ func (c *cache) set(k string, x interface{}, d time.Duration) {
 	}
 }
 
+// Add an item to the cache, replacing any existing item, using the default
+// expiration.
+func (c *cache) SetDefault(k string, x interface{}) {
+	c.Set(k, x, DefaultExpiration)
+}
+
 // Add an item to the cache only if an item doesn't already exist for the given
 // key, or if the existing item has expired. Returns an error otherwise.
 func (c *cache) Add(k string, x interface{}, d time.Duration) error {
@@ -129,6 +135,36 @@ func (c *cache) Get(k string) (interface{}, bool) {
 	return item.Object, true
 }
 
+// GetWithExpiration returns an item and its expiration time from the cache.
+// It returns the item or nil, the expiration time if one is set (if the item
+// never expires a zero value for time.Time is returned), and a bool indicating
+// whether the key was found.
+func (c *cache) GetWithExpiration(k string) (interface{}, time.Time, bool) {
+	c.mu.RLock()
+	// "Inlining" of get and Expired
+	item, found := c.items[k]
+	if !found {
+		c.mu.RUnlock()
+		return nil, time.Time{}, false
+	}
+
+	if item.Expiration > 0 {
+		if time.Now().UnixNano() > item.Expiration {
+			c.mu.RUnlock()
+			return nil, time.Time{}, false
+		}
+
+		// Return the item and the expiration time
+		c.mu.RUnlock()
+		return item.Object, time.Unix(0, item.Expiration), true
+	}
+
+	// If expiration <= 0 (i.e. no expiration time set) then return the item
+	// and a zeroed time.Time
+	c.mu.RUnlock()
+	return item.Object, time.Time{}, true
+}
+
 func (c *cache) get(k string) (interface{}, bool) {
 	item, found := c.items[k]
 	if !found {
@@ -998,19 +1034,26 @@ func (c *cache) LoadFile(fname string) error {
 	return fp.Close()
 }
 
-// Returns the items in the cache. This may include items that have expired,
+// Copies all unexpired items in the cache into a new map and returns it.
-// but have not yet been cleaned up. If this is significant, the Expiration
-// fields of the items should be checked. Note that explicit synchronization
-// is needed to use a cache and its corresponding Items() return value at
-// the same time, as the map is shared.
 func (c *cache) Items() map[string]Item {
 	c.mu.RLock()
 	defer c.mu.RUnlock()
-	return c.items
+	m := make(map[string]Item, len(c.items))
+	now := time.Now().UnixNano()
+	for k, v := range c.items {
+		// "Inlining" of Expired
+		if v.Expiration > 0 {
+			if now > v.Expiration {
+				continue
+			}
+		}
+		m[k] = v
+	}
+	return m
 }
 
 // Returns the number of items in the cache. This may include items that have
-// expired, but have not yet been cleaned up. Equivalent to len(c.Items()).
+// expired, but have not yet been cleaned up.
 func (c *cache) ItemCount() int {
 	c.mu.RLock()
 	n := len(c.items)
@@ -1031,7 +1074,6 @@ type janitor struct {
 }
 
 func (j *janitor) Run(c *cache) {
-	j.stop = make(chan bool)
 	ticker := time.NewTicker(j.Interval)
 	for {
 		select {
@@ -1051,6 +1093,7 @@ func stopJanitor(c *Cache) {
 func runJanitor(c *cache, ci time.Duration) {
 	j := &janitor{
 		Interval: ci,
+		stop:     make(chan bool),
 	}
 	c.janitor = j
 	go j.Run(c)

cache_test.go

@@ -1459,7 +1459,7 @@ func BenchmarkRWMutexMapGet(b *testing.B) {
 
 func BenchmarkRWMutexInterfaceMapGetStruct(b *testing.B) {
 	b.StopTimer()
-	s := struct{name string}{name: "foo"}
+	s := struct{ name string }{name: "foo"}
 	m := map[interface{}]string{
 		s: "bar",
 	}
@@ -1555,7 +1555,7 @@ func benchmarkCacheGetManyConcurrent(b *testing.B, exp time.Duration) {
 	tc := New(exp, 0)
 	keys := make([]string, n)
 	for i := 0; i < n; i++ {
-		k := "foo" + strconv.Itoa(n)
+		k := "foo" + strconv.Itoa(i)
 		keys[i] = k
 		tc.Set(k, "bar", DefaultExpiration)
 	}
@@ -1563,12 +1563,12 @@ func benchmarkCacheGetManyConcurrent(b *testing.B, exp time.Duration) {
 	wg := new(sync.WaitGroup)
 	wg.Add(n)
 	for _, v := range keys {
-		go func() {
+		go func(k string) {
 			for j := 0; j < each; j++ {
-				tc.Get(v)
+				tc.Get(k)
 			}
 			wg.Done()
-		}()
+		}(v)
 	}
 	b.StartTimer()
 	wg.Wait()
@@ -1676,3 +1676,96 @@ func BenchmarkDeleteExpiredLoop(b *testing.B) {
 		tc.DeleteExpired()
 	}
 }
+
+func TestGetWithExpiration(t *testing.T) {
+	tc := New(DefaultExpiration, 0)
+
+	a, expiration, found := tc.GetWithExpiration("a")
+	if found || a != nil || !expiration.IsZero() {
+		t.Error("Getting A found value that shouldn't exist:", a)
+	}
+
+	b, expiration, found := tc.GetWithExpiration("b")
+	if found || b != nil || !expiration.IsZero() {
+		t.Error("Getting B found value that shouldn't exist:", b)
+	}
+
+	c, expiration, found := tc.GetWithExpiration("c")
+	if found || c != nil || !expiration.IsZero() {
+		t.Error("Getting C found value that shouldn't exist:", c)
+	}
+
+	tc.Set("a", 1, DefaultExpiration)
+	tc.Set("b", "b", DefaultExpiration)
+	tc.Set("c", 3.5, DefaultExpiration)
+	tc.Set("d", 1, NoExpiration)
+	tc.Set("e", 1, 50*time.Millisecond)
+
+	x, expiration, found := tc.GetWithExpiration("a")
+	if !found {
+		t.Error("a was not found while getting a2")
+	}
+	if x == nil {
+		t.Error("x for a is nil")
+	} else if a2 := x.(int); a2+2 != 3 {
+		t.Error("a2 (which should be 1) plus 2 does not equal 3; value:", a2)
+	}
+	if !expiration.IsZero() {
+		t.Error("expiration for a is not a zeroed time")
+	}
+
+	x, expiration, found = tc.GetWithExpiration("b")
+	if !found {
+		t.Error("b was not found while getting b2")
+	}
+	if x == nil {
+		t.Error("x for b is nil")
+	} else if b2 := x.(string); b2+"B" != "bB" {
+		t.Error("b2 (which should be b) plus B does not equal bB; value:", b2)
+	}
+	if !expiration.IsZero() {
+		t.Error("expiration for b is not a zeroed time")
+	}
+
+	x, expiration, found = tc.GetWithExpiration("c")
+	if !found {
+		t.Error("c was not found while getting c2")
+	}
+	if x == nil {
+		t.Error("x for c is nil")
+	} else if c2 := x.(float64); c2+1.2 != 4.7 {
+		t.Error("c2 (which should be 3.5) plus 1.2 does not equal 4.7; value:", c2)
+	}
+	if !expiration.IsZero() {
+		t.Error("expiration for c is not a zeroed time")
+	}
+
+	x, expiration, found = tc.GetWithExpiration("d")
+	if !found {
+		t.Error("d was not found while getting d2")
+	}
+	if x == nil {
+		t.Error("x for d is nil")
+	} else if d2 := x.(int); d2+2 != 3 {
+		t.Error("d (which should be 1) plus 2 does not equal 3; value:", d2)
+	}
+	if !expiration.IsZero() {
+		t.Error("expiration for d is not a zeroed time")
+	}
+
+	x, expiration, found = tc.GetWithExpiration("e")
+	if !found {
+		t.Error("e was not found while getting e2")
+	}
+	if x == nil {
+		t.Error("x for e is nil")
+	} else if e2 := x.(int); e2+2 != 3 {
+		t.Error("e (which should be 1) plus 2 does not equal 3; value:", e2)
+	}
+	if expiration.UnixNano() != tc.items["e"].Expiration {
+		t.Error("expiration for e is not the correct time")
+	}
+	if expiration.UnixNano() < time.Now().UnixNano() {
+		t.Error("expiration for e is in the past")
+	}
+}

sharded_test.go

@@ -65,7 +65,7 @@ func benchmarkShardedCacheGetManyConcurrent(b *testing.B, exp time.Duration) {
 	tsc := unexportedNewSharded(exp, 0, 20)
 	keys := make([]string, n)
 	for i := 0; i < n; i++ {
-		k := "foo" + strconv.Itoa(n)
+		k := "foo" + strconv.Itoa(i)
 		keys[i] = k
 		tsc.Set(k, "bar", DefaultExpiration)
 	}
@@ -73,12 +73,12 @@ func benchmarkShardedCacheGetManyConcurrent(b *testing.B, exp time.Duration) {
 	wg := new(sync.WaitGroup)
 	wg.Add(n)
 	for _, v := range keys {
-		go func() {
+		go func(k string) {
 			for j := 0; j < each; j++ {
-				tsc.Get(v)
+				tsc.Get(k)
 			}
 			wg.Done()
-		}()
+		}(v)
 	}
 	b.StartTimer()
 	wg.Wait()