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author | Christopher Speller <crspeller@gmail.com> | 2016-09-23 10:17:51 -0400 |
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committer | GitHub <noreply@github.com> | 2016-09-23 10:17:51 -0400 |
commit | 2ca0e8f9a0f9863555a26e984cde15efff9ef8f8 (patch) | |
tree | daae1ee67b14a3d0a84424f2a304885d9e75ce2b /vendor/github.com/hashicorp/golang-lru/simplelru | |
parent | 6d62d65b2dc85855aabea036cbd44f6059e19d13 (diff) | |
download | chat-2ca0e8f9a0f9863555a26e984cde15efff9ef8f8.tar.gz chat-2ca0e8f9a0f9863555a26e984cde15efff9ef8f8.tar.bz2 chat-2ca0e8f9a0f9863555a26e984cde15efff9ef8f8.zip |
Updating golang dependancies (#4075)
Diffstat (limited to 'vendor/github.com/hashicorp/golang-lru/simplelru')
-rw-r--r-- | vendor/github.com/hashicorp/golang-lru/simplelru/lru.go | 160 | ||||
-rw-r--r-- | vendor/github.com/hashicorp/golang-lru/simplelru/lru_test.go | 167 |
2 files changed, 327 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/golang-lru/simplelru/lru.go b/vendor/github.com/hashicorp/golang-lru/simplelru/lru.go new file mode 100644 index 000000000..cb416b394 --- /dev/null +++ b/vendor/github.com/hashicorp/golang-lru/simplelru/lru.go @@ -0,0 +1,160 @@ +package simplelru + +import ( + "container/list" + "errors" +) + +// EvictCallback is used to get a callback when a cache entry is evicted +type EvictCallback func(key interface{}, value interface{}) + +// LRU implements a non-thread safe fixed size LRU cache +type LRU struct { + size int + evictList *list.List + items map[interface{}]*list.Element + onEvict EvictCallback +} + +// entry is used to hold a value in the evictList +type entry struct { + key interface{} + value interface{} +} + +// NewLRU constructs an LRU of the given size +func NewLRU(size int, onEvict EvictCallback) (*LRU, error) { + if size <= 0 { + return nil, errors.New("Must provide a positive size") + } + c := &LRU{ + size: size, + evictList: list.New(), + items: make(map[interface{}]*list.Element), + onEvict: onEvict, + } + return c, nil +} + +// Purge is used to completely clear the cache +func (c *LRU) Purge() { + for k, v := range c.items { + if c.onEvict != nil { + c.onEvict(k, v.Value.(*entry).value) + } + delete(c.items, k) + } + c.evictList.Init() +} + +// Add adds a value to the cache. Returns true if an eviction occurred. +func (c *LRU) Add(key, value interface{}) bool { + // Check for existing item + if ent, ok := c.items[key]; ok { + c.evictList.MoveToFront(ent) + ent.Value.(*entry).value = value + return false + } + + // Add new item + ent := &entry{key, value} + entry := c.evictList.PushFront(ent) + c.items[key] = entry + + evict := c.evictList.Len() > c.size + // Verify size not exceeded + if evict { + c.removeOldest() + } + return evict +} + +// Get looks up a key's value from the cache. +func (c *LRU) Get(key interface{}) (value interface{}, ok bool) { + if ent, ok := c.items[key]; ok { + c.evictList.MoveToFront(ent) + return ent.Value.(*entry).value, true + } + return +} + +// Check 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 +// the "recently used"-ness of the key. +func (c *LRU) Peek(key interface{}) (value interface{}, ok bool) { + if ent, ok := c.items[key]; ok { + return ent.Value.(*entry).value, true + } + return nil, ok +} + +// Remove removes the provided key from the cache, returning if the +// key was contained. +func (c *LRU) Remove(key interface{}) bool { + if ent, ok := c.items[key]; ok { + c.removeElement(ent) + return true + } + return false +} + +// RemoveOldest removes the oldest item from the cache. +func (c *LRU) RemoveOldest() (interface{}, interface{}, bool) { + ent := c.evictList.Back() + if ent != nil { + c.removeElement(ent) + kv := ent.Value.(*entry) + return kv.key, kv.value, true + } + return nil, nil, false +} + +// GetOldest returns the oldest entry +func (c *LRU) GetOldest() (interface{}, interface{}, bool) { + ent := c.evictList.Back() + if ent != nil { + kv := ent.Value.(*entry) + return kv.key, kv.value, true + } + return nil, nil, false +} + +// Keys returns a slice of the keys in the cache, from oldest to newest. +func (c *LRU) Keys() []interface{} { + keys := make([]interface{}, len(c.items)) + i := 0 + for ent := c.evictList.Back(); ent != nil; ent = ent.Prev() { + keys[i] = ent.Value.(*entry).key + i++ + } + return keys +} + +// Len returns the number of items in the cache. +func (c *LRU) Len() int { + return c.evictList.Len() +} + +// removeOldest removes the oldest item from the cache. +func (c *LRU) removeOldest() { + ent := c.evictList.Back() + if ent != nil { + c.removeElement(ent) + } +} + +// removeElement is used to remove a given list element from the cache +func (c *LRU) removeElement(e *list.Element) { + c.evictList.Remove(e) + kv := e.Value.(*entry) + delete(c.items, kv.key) + if c.onEvict != nil { + c.onEvict(kv.key, kv.value) + } +} diff --git a/vendor/github.com/hashicorp/golang-lru/simplelru/lru_test.go b/vendor/github.com/hashicorp/golang-lru/simplelru/lru_test.go new file mode 100644 index 000000000..a958934f6 --- /dev/null +++ b/vendor/github.com/hashicorp/golang-lru/simplelru/lru_test.go @@ -0,0 +1,167 @@ +package simplelru + +import "testing" + +func TestLRU(t *testing.T) { + evictCounter := 0 + onEvicted := func(k interface{}, v interface{}) { + if k != v { + t.Fatalf("Evict values not equal (%v!=%v)", k, v) + } + evictCounter += 1 + } + l, err := NewLRU(128, onEvicted) + if err != nil { + t.Fatalf("err: %v", err) + } + + for i := 0; i < 256; i++ { + l.Add(i, i) + } + if l.Len() != 128 { + t.Fatalf("bad len: %v", l.Len()) + } + + if evictCounter != 128 { + t.Fatalf("bad evict count: %v", evictCounter) + } + + for i, k := range l.Keys() { + if v, ok := l.Get(k); !ok || v != k || v != i+128 { + t.Fatalf("bad key: %v", k) + } + } + for i := 0; i < 128; i++ { + _, ok := l.Get(i) + if ok { + t.Fatalf("should be evicted") + } + } + for i := 128; i < 256; i++ { + _, ok := l.Get(i) + if !ok { + t.Fatalf("should not be evicted") + } + } + for i := 128; i < 192; i++ { + ok := l.Remove(i) + if !ok { + t.Fatalf("should be contained") + } + ok = l.Remove(i) + if ok { + t.Fatalf("should not be contained") + } + _, ok = l.Get(i) + if ok { + t.Fatalf("should be deleted") + } + } + + l.Get(192) // expect 192 to be last key in l.Keys() + + for i, k := range l.Keys() { + if (i < 63 && k != i+193) || (i == 63 && k != 192) { + t.Fatalf("out of order key: %v", k) + } + } + + l.Purge() + if l.Len() != 0 { + t.Fatalf("bad len: %v", l.Len()) + } + if _, ok := l.Get(200); ok { + t.Fatalf("should contain nothing") + } +} + +func TestLRU_GetOldest_RemoveOldest(t *testing.T) { + l, err := NewLRU(128, nil) + if err != nil { + t.Fatalf("err: %v", err) + } + for i := 0; i < 256; i++ { + l.Add(i, i) + } + k, _, ok := l.GetOldest() + if !ok { + t.Fatalf("missing") + } + if k.(int) != 128 { + t.Fatalf("bad: %v", k) + } + + k, _, ok = l.RemoveOldest() + if !ok { + t.Fatalf("missing") + } + if k.(int) != 128 { + t.Fatalf("bad: %v", k) + } + + k, _, ok = l.RemoveOldest() + if !ok { + t.Fatalf("missing") + } + if k.(int) != 129 { + t.Fatalf("bad: %v", k) + } +} + +// Test that Add returns true/false if an eviction occurred +func TestLRU_Add(t *testing.T) { + evictCounter := 0 + onEvicted := func(k interface{}, v interface{}) { + evictCounter += 1 + } + + l, err := NewLRU(1, onEvicted) + if err != nil { + t.Fatalf("err: %v", err) + } + + if l.Add(1, 1) == true || evictCounter != 0 { + t.Errorf("should not have an eviction") + } + if l.Add(2, 2) == false || evictCounter != 1 { + t.Errorf("should have an eviction") + } +} + +// Test that Contains doesn't update recent-ness +func TestLRU_Contains(t *testing.T) { + l, err := NewLRU(2, nil) + if err != nil { + t.Fatalf("err: %v", err) + } + + l.Add(1, 1) + l.Add(2, 2) + if !l.Contains(1) { + t.Errorf("1 should be contained") + } + + l.Add(3, 3) + if l.Contains(1) { + t.Errorf("Contains should not have updated recent-ness of 1") + } +} + +// Test that Peek doesn't update recent-ness +func TestLRU_Peek(t *testing.T) { + l, err := NewLRU(2, nil) + if err != nil { + t.Fatalf("err: %v", err) + } + + l.Add(1, 1) + l.Add(2, 2) + if v, ok := l.Peek(1); !ok || v != 1 { + t.Errorf("1 should be set to 1: %v, %v", v, ok) + } + + l.Add(3, 3) + if l.Contains(1) { + t.Errorf("should not have updated recent-ness of 1") + } +} |