1 files changed, 236 insertions, 0 deletions
diff --git a/vendor/github.com/allegro/bigcache/shard.go b/vendor/github.com/allegro/bigcache/shard.go
new file mode 100644
index 000000000..56a9fb089
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/shard.go
@@ -0,0 +1,236 @@
+package bigcache
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+
+	"github.com/allegro/bigcache/queue"
+)
+
+type onRemoveCallback func(wrappedEntry []byte, reason RemoveReason)
+
+type cacheShard struct {
+	hashmap     map[uint64]uint32
+	entries     queue.BytesQueue
+	lock        sync.RWMutex
+	entryBuffer []byte
+	onRemove    onRemoveCallback
+
+	isVerbose  bool
+	logger     Logger
+	clock      clock
+	lifeWindow uint64
+
+	stats Stats
+}
+
+func (s *cacheShard) get(key string, hashedKey uint64) ([]byte, error) {
+	s.lock.RLock()
+	itemIndex := s.hashmap[hashedKey]
+
+	if itemIndex == 0 {
+		s.lock.RUnlock()
+		s.miss()
+		return nil, notFound(key)
+	}
+
+	wrappedEntry, err := s.entries.Get(int(itemIndex))
+	if err != nil {
+		s.lock.RUnlock()
+		s.miss()
+		return nil, err
+	}
+	if entryKey := readKeyFromEntry(wrappedEntry); key != entryKey {
+		if s.isVerbose {
+			s.logger.Printf("Collision detected. Both %q and %q have the same hash %x", key, entryKey, hashedKey)
+		}
+		s.lock.RUnlock()
+		s.collision()
+		return nil, notFound(key)
+	}
+	s.lock.RUnlock()
+	s.hit()
+	return readEntry(wrappedEntry), nil
+}
+
+func (s *cacheShard) set(key string, hashedKey uint64, entry []byte) error {
+	currentTimestamp := uint64(s.clock.epoch())
+
+	s.lock.Lock()
+
+	if previousIndex := s.hashmap[hashedKey]; previousIndex != 0 {
+		if previousEntry, err := s.entries.Get(int(previousIndex)); err == nil {
+			resetKeyFromEntry(previousEntry)
+		}
+	}
+
+	if oldestEntry, err := s.entries.Peek(); err == nil {
+		s.onEvict(oldestEntry, currentTimestamp, s.removeOldestEntry)
+	}
+
+	w := wrapEntry(currentTimestamp, hashedKey, key, entry, &s.entryBuffer)
+
+	for {
+		if index, err := s.entries.Push(w); err == nil {
+			s.hashmap[hashedKey] = uint32(index)
+			s.lock.Unlock()
+			return nil
+		}
+		if s.removeOldestEntry(NoSpace) != nil {
+			s.lock.Unlock()
+			return fmt.Errorf("entry is bigger than max shard size")
+		}
+	}
+}
+
+func (s *cacheShard) del(key string, hashedKey uint64) error {
+	s.lock.RLock()
+	itemIndex := s.hashmap[hashedKey]
+
+	if itemIndex == 0 {
+		s.lock.RUnlock()
+		s.delmiss()
+		return notFound(key)
+	}
+
+	wrappedEntry, err := s.entries.Get(int(itemIndex))
+	if err != nil {
+		s.lock.RUnlock()
+		s.delmiss()
+		return err
+	}
+	s.lock.RUnlock()
+
+	s.lock.Lock()
+	{
+		delete(s.hashmap, hashedKey)
+		s.onRemove(wrappedEntry, Deleted)
+		resetKeyFromEntry(wrappedEntry)
+	}
+	s.lock.Unlock()
+
+	s.delhit()
+	return nil
+}
+
+func (s *cacheShard) onEvict(oldestEntry []byte, currentTimestamp uint64, evict func(reason RemoveReason) error) bool {
+	oldestTimestamp := readTimestampFromEntry(oldestEntry)
+	if currentTimestamp-oldestTimestamp > s.lifeWindow {
+		evict(Expired)
+		return true
+	}
+	return false
+}
+
+func (s *cacheShard) cleanUp(currentTimestamp uint64) {
+	s.lock.Lock()
+	for {
+		if oldestEntry, err := s.entries.Peek(); err != nil {
+			break
+		} else if evicted := s.onEvict(oldestEntry, currentTimestamp, s.removeOldestEntry); !evicted {
+			break
+		}
+	}
+	s.lock.Unlock()
+}
+
+func (s *cacheShard) getOldestEntry() ([]byte, error) {
+	return s.entries.Peek()
+}
+
+func (s *cacheShard) getEntry(index int) ([]byte, error) {
+	return s.entries.Get(index)
+}
+
+func (s *cacheShard) copyKeys() (keys []uint32, next int) {
+	keys = make([]uint32, len(s.hashmap))
+
+	s.lock.RLock()
+
+	for _, index := range s.hashmap {
+		keys[next] = index
+		next++
+	}
+
+	s.lock.RUnlock()
+	return keys, next
+}
+
+func (s *cacheShard) removeOldestEntry(reason RemoveReason) error {
+	oldest, err := s.entries.Pop()
+	if err == nil {
+		hash := readHashFromEntry(oldest)
+		delete(s.hashmap, hash)
+		s.onRemove(oldest, reason)
+		return nil
+	}
+	return err
+}
+
+func (s *cacheShard) reset(config Config) {
+	s.lock.Lock()
+	s.hashmap = make(map[uint64]uint32, config.initialShardSize())
+	s.entryBuffer = make([]byte, config.MaxEntrySize+headersSizeInBytes)
+	s.entries.Reset()
+	s.lock.Unlock()
+}
+
+func (s *cacheShard) len() int {
+	s.lock.RLock()
+	res := len(s.hashmap)
+	s.lock.RUnlock()
+	return res
+}
+
+func (s *cacheShard) capacity() int {
+	s.lock.RLock()
+	res := s.entries.Capacity()
+	s.lock.RUnlock()
+	return res
+}
+
+func (s *cacheShard) getStats() Stats {
+	var stats = Stats{
+		Hits:       atomic.LoadInt64(&s.stats.Hits),
+		Misses:     atomic.LoadInt64(&s.stats.Misses),
+		DelHits:    atomic.LoadInt64(&s.stats.DelHits),
+		DelMisses:  atomic.LoadInt64(&s.stats.DelMisses),
+		Collisions: atomic.LoadInt64(&s.stats.Collisions),
+	}
+	return stats
+}
+
+func (s *cacheShard) hit() {
+	atomic.AddInt64(&s.stats.Hits, 1)
+}
+
+func (s *cacheShard) miss() {
+	atomic.AddInt64(&s.stats.Misses, 1)
+}
+
+func (s *cacheShard) delhit() {
+	atomic.AddInt64(&s.stats.DelHits, 1)
+}
+
+func (s *cacheShard) delmiss() {
+	atomic.AddInt64(&s.stats.DelMisses, 1)
+}
+
+func (s *cacheShard) collision() {
+	atomic.AddInt64(&s.stats.Collisions, 1)
+}
+
+func initNewShard(config Config, callback onRemoveCallback, clock clock) *cacheShard {
+	return &cacheShard{
+		hashmap:     make(map[uint64]uint32, config.initialShardSize()),
+		entries:     *queue.NewBytesQueue(config.initialShardSize()*config.MaxEntrySize, config.maximumShardSize(), config.Verbose),
+		entryBuffer: make([]byte, config.MaxEntrySize+headersSizeInBytes),
+		onRemove:    callback,
+
+		isVerbose:  config.Verbose,
+		logger:     newLogger(config.Logger),
+		clock:      clock,
+		lifeWindow: uint64(config.LifeWindow.Seconds()),
+	}
+}