7 files changed, 103 insertions, 37 deletions
diff --git a/vendor/github.com/hashicorp/golang-lru/2q.go b/vendor/github.com/hashicorp/golang-lru/2q.go
index 337d9632..e474cd07 100644
--- a/vendor/github.com/hashicorp/golang-lru/2q.go
+++ b/vendor/github.com/hashicorp/golang-lru/2q.go
@@ -30,9 +30,9 @@ type TwoQueueCache struct {
 	size       int
 	recentSize int
 
-	recent      *simplelru.LRU
-	frequent    *simplelru.LRU
-	recentEvict *simplelru.LRU
+	recent      simplelru.LRUCache
+	frequent    simplelru.LRUCache
+	recentEvict simplelru.LRUCache
 	lock        sync.RWMutex
 }
 
@@ -84,7 +84,8 @@ func New2QParams(size int, recentRatio float64, ghostRatio float64) (*TwoQueueCa
 	return c, nil
 }
 
-func (c *TwoQueueCache) Get(key interface{}) (interface{}, bool) {
+// Get looks up a key's value from the cache.
+func (c *TwoQueueCache) Get(key interface{}) (value interface{}, ok bool) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 
@@ -105,6 +106,7 @@ func (c *TwoQueueCache) Get(key interface{}) (interface{}, bool) {
 	return nil, false
 }
 
+// Add adds a value to the cache.
 func (c *TwoQueueCache) Add(key, value interface{}) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
@@ -160,12 +162,15 @@ func (c *TwoQueueCache) ensureSpace(recentEvict bool) {
 	c.frequent.RemoveOldest()
 }
 
+// Len returns the number of items in the cache.
 func (c *TwoQueueCache) Len() int {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	return c.recent.Len() + c.frequent.Len()
 }
 
+// Keys returns a slice of the keys in the cache.
+// The frequently used keys are first in the returned slice.
 func (c *TwoQueueCache) Keys() []interface{} {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
@@ -174,6 +179,7 @@ func (c *TwoQueueCache) Keys() []interface{} {
 	return append(k1, k2...)
 }
 
+// Remove removes the provided key from the cache.
 func (c *TwoQueueCache) Remove(key interface{}) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
@@ -188,6 +194,7 @@ func (c *TwoQueueCache) Remove(key interface{}) {
 	}
 }
 
+// Purge is used to completely clear the cache.
 func (c *TwoQueueCache) Purge() {
 	c.lock.Lock()
 	defer c.lock.Unlock()
@@ -196,13 +203,17 @@ func (c *TwoQueueCache) Purge() {
 	c.recentEvict.Purge()
 }
 
+// Contains is used to check if the cache contains a key
+// without updating recency or frequency.
 func (c *TwoQueueCache) Contains(key interface{}) bool {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	return c.frequent.Contains(key) || c.recent.Contains(key)
 }
 
-func (c *TwoQueueCache) Peek(key interface{}) (interface{}, bool) {
+// Peek is used to inspect the cache value of a key
+// without updating recency or frequency.
+func (c *TwoQueueCache) Peek(key interface{}) (value interface{}, ok bool) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	if val, ok := c.frequent.Peek(key); ok {
diff --git a/vendor/github.com/hashicorp/golang-lru/arc.go b/vendor/github.com/hashicorp/golang-lru/arc.go
index a2a25281..555225a2 100644
--- a/vendor/github.com/hashicorp/golang-lru/arc.go
+++ b/vendor/github.com/hashicorp/golang-lru/arc.go
@@ -18,11 +18,11 @@ type ARCCache struct {
 	size int // Size is the total capacity of the cache
 	p    int // P is the dynamic preference towards T1 or T2
 
-	t1 *simplelru.LRU // T1 is the LRU for recently accessed items
-	b1 *simplelru.LRU // B1 is the LRU for evictions from t1
+	t1 simplelru.LRUCache // T1 is the LRU for recently accessed items
+	b1 simplelru.LRUCache // B1 is the LRU for evictions from t1
 
-	t2 *simplelru.LRU // T2 is the LRU for frequently accessed items
-	b2 *simplelru.LRU // B2 is the LRU for evictions from t2
+	t2 simplelru.LRUCache // T2 is the LRU for frequently accessed items
+	b2 simplelru.LRUCache // B2 is the LRU for evictions from t2
 
 	lock sync.RWMutex
 }
@@ -60,11 +60,11 @@ func NewARC(size int) (*ARCCache, error) {
 }
 
 // Get looks up a key's value from the cache.
-func (c *ARCCache) Get(key interface{}) (interface{}, bool) {
+func (c *ARCCache) Get(key interface{}) (value interface{}, ok bool) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 
-	// Ff the value is contained in T1 (recent), then
+	// If the value is contained in T1 (recent), then
 	// promote it to T2 (frequent)
 	if val, ok := c.t1.Peek(key); ok {
 		c.t1.Remove(key)
@@ -153,7 +153,7 @@ func (c *ARCCache) Add(key, value interface{}) {
 		// Remove from B2
 		c.b2.Remove(key)
 
-		// Add the key to the frequntly used list
+		// Add the key to the frequently used list
 		c.t2.Add(key, value)
 		return
 	}
@@ -247,7 +247,7 @@ func (c *ARCCache) Contains(key interface{}) bool {
 
 // Peek is used to inspect the cache value of a key
 // without updating recency or frequency.
-func (c *ARCCache) Peek(key interface{}) (interface{}, bool) {
+func (c *ARCCache) Peek(key interface{}) (value interface{}, ok bool) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	if val, ok := c.t1.Peek(key); ok {
diff --git a/vendor/github.com/hashicorp/golang-lru/doc.go b/vendor/github.com/hashicorp/golang-lru/doc.go
new file mode 100644
index 00000000..2547df97
--- /dev/null
+++ b/vendor/github.com/hashicorp/golang-lru/doc.go
@@ -0,0 +1,21 @@
+// Package lru provides three different LRU caches of varying sophistication.
+//
+// Cache is a simple LRU cache. It is based on the
+// LRU implementation in groupcache:
+// https://github.com/golang/groupcache/tree/master/lru
+//
+// TwoQueueCache tracks frequently used and recently used entries separately.
+// This avoids a burst of accesses from taking out frequently used entries,
+// at the cost of about 2x computational overhead and some extra bookkeeping.
+//
+// ARCCache is an adaptive replacement cache. It tracks recent evictions as
+// well as recent usage in both the frequent and recent caches. Its
+// computational overhead is comparable to TwoQueueCache, but the memory
+// overhead is linear with the size of the cache.
+//
+// ARC has been patented by IBM, so do not use it if that is problematic for
+// your program.
+//
+// All caches in this package take locks while operating, and are therefore
+// thread-safe for consumers.
+package lru
diff --git a/vendor/github.com/hashicorp/golang-lru/go.mod b/vendor/github.com/hashicorp/golang-lru/go.mod
new file mode 100644
index 00000000..824cb97e
--- /dev/null
+++ b/vendor/github.com/hashicorp/golang-lru/go.mod
@@ -0,0 +1 @@
+module github.com/hashicorp/golang-lru
diff --git a/vendor/github.com/hashicorp/golang-lru/lru.go b/vendor/github.com/hashicorp/golang-lru/lru.go
index a6285f98..c8d9b0a2 100644
--- a/vendor/github.com/hashicorp/golang-lru/lru.go
+++ b/vendor/github.com/hashicorp/golang-lru/lru.go
@@ -1,6 +1,3 @@
-// This package provides a simple LRU cache. It is based on the
-// LRU implementation in groupcache:
-// https://github.com/golang/groupcache/tree/master/lru
 package lru
 
 import (
@@ -11,11 +8,11 @@ import (
 
 // Cache is a thread-safe fixed size LRU cache.
 type Cache struct {
-	lru  *simplelru.LRU
+	lru  simplelru.LRUCache
 	lock sync.RWMutex
 }
 
-// New creates an LRU of the given size
+// New creates an LRU of the given size.
 func New(size int) (*Cache, error) {
 	return NewWithEvict(size, nil)
 }
@@ -33,7 +30,7 @@ func NewWithEvict(size int, onEvicted func(key interface{}, value interface{}))
 	return c, nil
 }
 
-// Purge is used to completely clear the cache
+// Purge is used to completely clear the cache.
 func (c *Cache) Purge() {
 	c.lock.Lock()
 	c.lru.Purge()
@@ -41,30 +38,30 @@ func (c *Cache) Purge() {
 }
 
 // Add adds a value to the cache.  Returns true if an eviction occurred.
-func (c *Cache) Add(key, value interface{}) bool {
+func (c *Cache) Add(key, value interface{}) (evicted bool) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	return c.lru.Add(key, value)
 }
 
 // Get looks up a key's value from the cache.
-func (c *Cache) Get(key interface{}) (interface{}, bool) {
+func (c *Cache) Get(key interface{}) (value interface{}, ok bool) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	return c.lru.Get(key)
 }
 
-// Check if a key is in the cache, without updating the recent-ness
-// or deleting it for being stale.
+// Contains checks if a key is in the cache, without updating the
+// recent-ness or deleting it for being stale.
 func (c *Cache) Contains(key interface{}) bool {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	return c.lru.Contains(key)
 }
 
-// Returns the key value (or undefined if not found) without updating
+// Peek returns the key value (or undefined if not found) without updating
 // the "recently used"-ness of the key.
-func (c *Cache) Peek(key interface{}) (interface{}, bool) {
+func (c *Cache) Peek(key interface{}) (value interface{}, ok bool) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	return c.lru.Peek(key)
@@ -73,16 +70,15 @@ func (c *Cache) Peek(key interface{}) (interface{}, bool) {
 // ContainsOrAdd checks if a key is in the cache  without updating the
 // recent-ness or deleting it for being stale,  and if not, adds the value.
 // Returns whether found and whether an eviction occurred.
-func (c *Cache) ContainsOrAdd(key, value interface{}) (ok, evict bool) {
+func (c *Cache) ContainsOrAdd(key, value interface{}) (ok, evicted bool) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 
 	if c.lru.Contains(key) {
 		return true, false
-	} else {
-		evict := c.lru.Add(key, value)
-		return false, evict
 	}
+	evicted = c.lru.Add(key, value)
+	return false, evicted
 }
 
 // Remove removes the provided key from the cache.
diff --git a/vendor/github.com/hashicorp/golang-lru/simplelru/lru.go b/vendor/github.com/hashicorp/golang-lru/simplelru/lru.go
index cb416b39..5673773b 100644
--- a/vendor/github.com/hashicorp/golang-lru/simplelru/lru.go
+++ b/vendor/github.com/hashicorp/golang-lru/simplelru/lru.go
@@ -36,7 +36,7 @@ func NewLRU(size int, onEvict EvictCallback) (*LRU, error) {
 	return c, nil
 }
 
-// Purge is used to completely clear the cache
+// Purge is used to completely clear the cache.
 func (c *LRU) Purge() {
 	for k, v := range c.items {
 		if c.onEvict != nil {
@@ -48,7 +48,7 @@ func (c *LRU) Purge() {
 }
 
 // Add adds a value to the cache.  Returns true if an eviction occurred.
-func (c *LRU) Add(key, value interface{}) bool {
+func (c *LRU) Add(key, value interface{}) (evicted bool) {
 	// Check for existing item
 	if ent, ok := c.items[key]; ok {
 		c.evictList.MoveToFront(ent)
@@ -78,17 +78,18 @@ func (c *LRU) Get(key interface{}) (value interface{}, ok bool) {
 	return
 }
 
-// Check if a key is in the cache, without updating the recent-ness
+// Contains checks if a key is in the cache, without updating the recent-ness
 // or deleting it for being stale.
 func (c *LRU) Contains(key interface{}) (ok bool) {
 	_, ok = c.items[key]
 	return ok
 }
 
-// Returns the key value (or undefined if not found) without updating
+// Peek returns the key value (or undefined if not found) without updating
 // the "recently used"-ness of the key.
 func (c *LRU) Peek(key interface{}) (value interface{}, ok bool) {
-	if ent, ok := c.items[key]; ok {
+	var ent *list.Element
+	if ent, ok = c.items[key]; ok {
 		return ent.Value.(*entry).value, true
 	}
 	return nil, ok
@@ -96,7 +97,7 @@ func (c *LRU) Peek(key interface{}) (value interface{}, ok bool) {
 
 // Remove removes the provided key from the cache, returning if the
 // key was contained.
-func (c *LRU) Remove(key interface{}) bool {
+func (c *LRU) Remove(key interface{}) (present bool) {
 	if ent, ok := c.items[key]; ok {
 		c.removeElement(ent)
 		return true
@@ -105,7 +106,7 @@ func (c *LRU) Remove(key interface{}) bool {
 }
 
 // RemoveOldest removes the oldest item from the cache.
-func (c *LRU) RemoveOldest() (interface{}, interface{}, bool) {
+func (c *LRU) RemoveOldest() (key interface{}, value interface{}, ok bool) {
 	ent := c.evictList.Back()
 	if ent != nil {
 		c.removeElement(ent)
@@ -116,7 +117,7 @@ func (c *LRU) RemoveOldest() (interface{}, interface{}, bool) {
 }
 
 // GetOldest returns the oldest entry
-func (c *LRU) GetOldest() (interface{}, interface{}, bool) {
+func (c *LRU) GetOldest() (key interface{}, value interface{}, ok bool) {
 	ent := c.evictList.Back()
 	if ent != nil {
 		kv := ent.Value.(*entry)
diff --git a/vendor/github.com/hashicorp/golang-lru/simplelru/lru_interface.go b/vendor/github.com/hashicorp/golang-lru/simplelru/lru_interface.go
new file mode 100644
index 00000000..74c70774
--- /dev/null
+++ b/vendor/github.com/hashicorp/golang-lru/simplelru/lru_interface.go
@@ -0,0 +1,36 @@
+package simplelru
+
+// LRUCache is the interface for simple LRU cache.
+type LRUCache interface {
+	// Adds a value to the cache, returns true if an eviction occurred and
+	// updates the "recently used"-ness of the key.
+	Add(key, value interface{}) bool
+
+	// Returns key's value from the cache and
+	// updates the "recently used"-ness of the key. #value, isFound
+	Get(key interface{}) (value interface{}, ok bool)
+
+	// Check if a key exsists in cache without updating the recent-ness.
+	Contains(key interface{}) (ok bool)
+
+	// Returns key's value without updating the "recently used"-ness of the key.
+	Peek(key interface{}) (value interface{}, ok bool)
+
+	// Removes a key from the cache.
+	Remove(key interface{}) bool
+
+	// Removes the oldest entry from cache.
+	RemoveOldest() (interface{}, interface{}, bool)
+
+	// Returns the oldest entry from the cache. #key, value, isFound
+	GetOldest() (interface{}, interface{}, bool)
+
+	// Returns a slice of the keys in the cache, from oldest to newest.
+	Keys() []interface{}
+
+	// Returns the number of items in the cache.
+	Len() int
+
+	// Clear all cache entries
+	Purge()
+}