cmd, core, eth, light, trie: add trie read caching layer

18 files changed, 1430 insertions, 0 deletions

diff --git a/vendor/github.com/allegro/bigcache/LICENSE b/vendor/github.com/allegro/bigcache/LICENSE
new file mode 100644
index 000000000..8dada3eda
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/LICENSE
@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "{}"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright {yyyy} {name of copyright owner}
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/vendor/github.com/allegro/bigcache/README.md b/vendor/github.com/allegro/bigcache/README.md
new file mode 100644
index 000000000..c23f7f36c
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/README.md
@@ -0,0 +1,150 @@
+# BigCache [![Build Status](https://travis-ci.org/allegro/bigcache.svg?branch=master)](https://travis-ci.org/allegro/bigcache) [![Coverage Status](https://coveralls.io/repos/github/allegro/bigcache/badge.svg?branch=master)](https://coveralls.io/github/allegro/bigcache?branch=master) [![GoDoc](https://godoc.org/github.com/allegro/bigcache?status.svg)](https://godoc.org/github.com/allegro/bigcache) [![Go Report Card](https://goreportcard.com/badge/github.com/allegro/bigcache)](https://goreportcard.com/report/github.com/allegro/bigcache)
+
+Fast, concurrent, evicting in-memory cache written to keep big number of entries without impact on performance.
+BigCache keeps entries on heap but omits GC for them. To achieve that operations on bytes arrays take place,
+therefore entries (de)serialization in front of the cache will be needed in most use cases.
+
+## Usage
+
+### Simple initialization
+
+```go
+import "github.com/allegro/bigcache"
+
+cache, _ := bigcache.NewBigCache(bigcache.DefaultConfig(10 * time.Minute))
+
+cache.Set("my-unique-key", []byte("value"))
+
+entry, _ := cache.Get("my-unique-key")
+fmt.Println(string(entry))
+```
+
+### Custom initialization
+
+When cache load can be predicted in advance then it is better to use custom initialization because additional memory
+allocation can be avoided in that way.
+
+```go
+import (
+	"log"
+
+	"github.com/allegro/bigcache"
+)
+
+config := bigcache.Config {
+		// number of shards (must be a power of 2)
+		Shards: 1024,
+		// time after which entry can be evicted
+		LifeWindow: 10 * time.Minute,
+		// rps * lifeWindow, used only in initial memory allocation
+		MaxEntriesInWindow: 1000 * 10 * 60,
+		// max entry size in bytes, used only in initial memory allocation
+		MaxEntrySize: 500,
+		// prints information about additional memory allocation
+		Verbose: true,
+		// cache will not allocate more memory than this limit, value in MB
+		// if value is reached then the oldest entries can be overridden for the new ones
+		// 0 value means no size limit
+		HardMaxCacheSize: 8192,
+		// callback fired when the oldest entry is removed because of its expiration time or no space left
+		// for the new entry, or because delete was called. A bitmask representing the reason will be returned.
+		// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
+		OnRemove: nil,
+		// OnRemoveWithReason is a callback fired when the oldest entry is removed because of its expiration time or no space left
+		// for the new entry, or because delete was called. A constant representing the reason will be passed through.
+		// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
+		// Ignored if OnRemove is specified.
+		OnRemoveWithReason: nil,
+	}
+
+cache, initErr := bigcache.NewBigCache(config)
+if initErr != nil {
+	log.Fatal(initErr)
+}
+
+cache.Set("my-unique-key", []byte("value"))
+
+if entry, err := cache.Get("my-unique-key"); err == nil {
+	fmt.Println(string(entry))
+}
+```
+
+## Benchmarks
+
+Three caches were compared: bigcache, [freecache](https://github.com/coocood/freecache) and map.
+Benchmark tests were made using an i7-6700K with 32GB of RAM on Windows 10.
+
+### Writes and reads
+
+```bash
+cd caches_bench; go test -bench=. -benchtime=10s ./... -timeout 30m
+
+BenchmarkMapSet-8                        3000000               569 ns/op             202 B/op          3 allocs/op
+BenchmarkConcurrentMapSet-8              1000000              1592 ns/op             347 B/op          8 allocs/op
+BenchmarkFreeCacheSet-8                  3000000               775 ns/op             355 B/op          2 allocs/op
+BenchmarkBigCacheSet-8                   3000000               640 ns/op             303 B/op          2 allocs/op
+BenchmarkMapGet-8                        5000000               407 ns/op              24 B/op          1 allocs/op
+BenchmarkConcurrentMapGet-8              3000000               558 ns/op              24 B/op          2 allocs/op
+BenchmarkFreeCacheGet-8                  2000000               682 ns/op             136 B/op          2 allocs/op
+BenchmarkBigCacheGet-8                   3000000               512 ns/op             152 B/op          4 allocs/op
+BenchmarkBigCacheSetParallel-8          10000000               225 ns/op             313 B/op          3 allocs/op
+BenchmarkFreeCacheSetParallel-8         10000000               218 ns/op             341 B/op          3 allocs/op
+BenchmarkConcurrentMapSetParallel-8      5000000               318 ns/op             200 B/op          6 allocs/op
+BenchmarkBigCacheGetParallel-8          20000000               178 ns/op             152 B/op          4 allocs/op
+BenchmarkFreeCacheGetParallel-8         20000000               295 ns/op             136 B/op          3 allocs/op
+BenchmarkConcurrentMapGetParallel-8     10000000               237 ns/op              24 B/op          2 allocs/op
+```
+
+Writes and reads in bigcache are faster than in freecache.
+Writes to map are the slowest.
+
+### GC pause time
+
+```bash
+cd caches_bench; go run caches_gc_overhead_comparison.go
+
+Number of entries:  20000000
+GC pause for bigcache:  5.8658ms
+GC pause for freecache:  32.4341ms
+GC pause for map:  52.9661ms
+```
+
+Test shows how long are the GC pauses for caches filled with 20mln of entries.
+Bigcache and freecache have very similar GC pause time.
+It is clear that both reduce GC overhead in contrast to map
+which GC pause time took more than 10 seconds.
+
+## How it works
+
+BigCache relies on optimization presented in 1.5 version of Go ([issue-9477](https://github.com/golang/go/issues/9477)).
+This optimization states that if map without pointers in keys and values is used then GC will omit its content.
+Therefore BigCache uses `map[uint64]uint32` where keys are hashed and values are offsets of entries.
+
+Entries are kept in bytes array, to omit GC again.
+Bytes array size can grow to gigabytes without impact on performance
+because GC will only see single pointer to it.
+
+## Bigcache vs Freecache
+
+Both caches provide the same core features but they reduce GC overhead in different ways.
+Bigcache relies on `map[uint64]uint32`, freecache implements its own mapping built on
+slices to reduce number of pointers.
+
+Results from benchmark tests are presented above.
+One of the advantage of bigcache over freecache is that you don’t need to know
+the size of the cache in advance, because when bigcache is full,
+it can allocate additional memory for new entries instead of
+overwriting existing ones as freecache does currently.
+However hard max size in bigcache also can be set, check [HardMaxCacheSize](https://godoc.org/github.com/allegro/bigcache#Config).
+
+## HTTP Server
+
+This package also includes an easily deployable HTTP implementation of BigCache, which can be found in the [server](/server) package.
+
+## More
+
+Bigcache genesis is described in allegro.tech blog post: [writing a very fast cache service in Go](http://allegro.tech/2016/03/writing-fast-cache-service-in-go.html)
+
+## License
+
+BigCache is released under the Apache 2.0 license (see [LICENSE](LICENSE))
diff --git a/vendor/github.com/allegro/bigcache/bigcache.go b/vendor/github.com/allegro/bigcache/bigcache.go
new file mode 100644
index 000000000..e6aee8663
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/bigcache.go
@@ -0,0 +1,202 @@
+package bigcache
+
+import (
+	"fmt"
+	"time"
+)
+
+const (
+	minimumEntriesInShard = 10 // Minimum number of entries in single shard
+)
+
+// BigCache is fast, concurrent, evicting cache created to keep big number of entries without impact on performance.
+// It keeps entries on heap but omits GC for them. To achieve that, operations take place on byte arrays,
+// therefore entries (de)serialization in front of the cache will be needed in most use cases.
+type BigCache struct {
+	shards       []*cacheShard
+	lifeWindow   uint64
+	clock        clock
+	hash         Hasher
+	config       Config
+	shardMask    uint64
+	maxShardSize uint32
+	close        chan struct{}
+}
+
+// RemoveReason is a value used to signal to the user why a particular key was removed in the OnRemove callback.
+type RemoveReason uint32
+
+const (
+	// Expired means the key is past its LifeWindow.
+	Expired RemoveReason = iota
+	// NoSpace means the key is the oldest and the cache size was at its maximum when Set was called, or the
+	// entry exceeded the maximum shard size.
+	NoSpace
+	// Deleted means Delete was called and this key was removed as a result.
+	Deleted
+)
+
+// NewBigCache initialize new instance of BigCache
+func NewBigCache(config Config) (*BigCache, error) {
+	return newBigCache(config, &systemClock{})
+}
+
+func newBigCache(config Config, clock clock) (*BigCache, error) {
+
+	if !isPowerOfTwo(config.Shards) {
+		return nil, fmt.Errorf("Shards number must be power of two")
+	}
+
+	if config.Hasher == nil {
+		config.Hasher = newDefaultHasher()
+	}
+
+	cache := &BigCache{
+		shards:       make([]*cacheShard, config.Shards),
+		lifeWindow:   uint64(config.LifeWindow.Seconds()),
+		clock:        clock,
+		hash:         config.Hasher,
+		config:       config,
+		shardMask:    uint64(config.Shards - 1),
+		maxShardSize: uint32(config.maximumShardSize()),
+		close:        make(chan struct{}),
+	}
+
+	var onRemove func(wrappedEntry []byte, reason RemoveReason)
+	if config.OnRemove != nil {
+		onRemove = cache.providedOnRemove
+	} else if config.OnRemoveWithReason != nil {
+		onRemove = cache.providedOnRemoveWithReason
+	} else {
+		onRemove = cache.notProvidedOnRemove
+	}
+
+	for i := 0; i < config.Shards; i++ {
+		cache.shards[i] = initNewShard(config, onRemove, clock)
+	}
+
+	if config.CleanWindow > 0 {
+		go func() {
+			ticker := time.NewTicker(config.CleanWindow)
+			defer ticker.Stop()
+			for {
+				select {
+				case t := <-ticker.C:
+					cache.cleanUp(uint64(t.Unix()))
+				case <-cache.close:
+					return
+				}
+			}
+		}()
+	}
+
+	return cache, nil
+}
+
+// Close is used to signal a shutdown of the cache when you are done with it.
+// This allows the cleaning goroutines to exit and ensures references are not
+// kept to the cache preventing GC of the entire cache.
+func (c *BigCache) Close() error {
+	close(c.close)
+	return nil
+}
+
+// Get reads entry for the key.
+// It returns an EntryNotFoundError when
+// no entry exists for the given key.
+func (c *BigCache) Get(key string) ([]byte, error) {
+	hashedKey := c.hash.Sum64(key)
+	shard := c.getShard(hashedKey)
+	return shard.get(key, hashedKey)
+}
+
+// Set saves entry under the key
+func (c *BigCache) Set(key string, entry []byte) error {
+	hashedKey := c.hash.Sum64(key)
+	shard := c.getShard(hashedKey)
+	return shard.set(key, hashedKey, entry)
+}
+
+// Delete removes the key
+func (c *BigCache) Delete(key string) error {
+	hashedKey := c.hash.Sum64(key)
+	shard := c.getShard(hashedKey)
+	return shard.del(key, hashedKey)
+}
+
+// Reset empties all cache shards
+func (c *BigCache) Reset() error {
+	for _, shard := range c.shards {
+		shard.reset(c.config)
+	}
+	return nil
+}
+
+// Len computes number of entries in cache
+func (c *BigCache) Len() int {
+	var len int
+	for _, shard := range c.shards {
+		len += shard.len()
+	}
+	return len
+}
+
+// Capacity returns amount of bytes store in the cache.
+func (c *BigCache) Capacity() int {
+	var len int
+	for _, shard := range c.shards {
+		len += shard.capacity()
+	}
+	return len
+}
+
+// Stats returns cache's statistics
+func (c *BigCache) Stats() Stats {
+	var s Stats
+	for _, shard := range c.shards {
+		tmp := shard.getStats()
+		s.Hits += tmp.Hits
+		s.Misses += tmp.Misses
+		s.DelHits += tmp.DelHits
+		s.DelMisses += tmp.DelMisses
+		s.Collisions += tmp.Collisions
+	}
+	return s
+}
+
+// Iterator returns iterator function to iterate over EntryInfo's from whole cache.
+func (c *BigCache) Iterator() *EntryInfoIterator {
+	return newIterator(c)
+}
+
+func (c *BigCache) onEvict(oldestEntry []byte, currentTimestamp uint64, evict func(reason RemoveReason) error) bool {
+	oldestTimestamp := readTimestampFromEntry(oldestEntry)
+	if currentTimestamp-oldestTimestamp > c.lifeWindow {
+		evict(Expired)
+		return true
+	}
+	return false
+}
+
+func (c *BigCache) cleanUp(currentTimestamp uint64) {
+	for _, shard := range c.shards {
+		shard.cleanUp(currentTimestamp)
+	}
+}
+
+func (c *BigCache) getShard(hashedKey uint64) (shard *cacheShard) {
+	return c.shards[hashedKey&c.shardMask]
+}
+
+func (c *BigCache) providedOnRemove(wrappedEntry []byte, reason RemoveReason) {
+	c.config.OnRemove(readKeyFromEntry(wrappedEntry), readEntry(wrappedEntry))
+}
+
+func (c *BigCache) providedOnRemoveWithReason(wrappedEntry []byte, reason RemoveReason) {
+	if c.config.onRemoveFilter == 0 || (1<<uint(reason))&c.config.onRemoveFilter > 0 {
+		c.config.OnRemoveWithReason(readKeyFromEntry(wrappedEntry), readEntry(wrappedEntry), reason)
+	}
+}
+
+func (c *BigCache) notProvidedOnRemove(wrappedEntry []byte, reason RemoveReason) {
+}
diff --git a/vendor/github.com/allegro/bigcache/bytes.go b/vendor/github.com/allegro/bigcache/bytes.go
new file mode 100644
index 000000000..3944bfe13
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/bytes.go
@@ -0,0 +1,14 @@
+// +build !appengine
+
+package bigcache
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+func bytesToString(b []byte) string {
+	bytesHeader := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	strHeader := reflect.StringHeader{Data: bytesHeader.Data, Len: bytesHeader.Len}
+	return *(*string)(unsafe.Pointer(&strHeader))
+}
diff --git a/vendor/github.com/allegro/bigcache/bytes_appengine.go b/vendor/github.com/allegro/bigcache/bytes_appengine.go
new file mode 100644
index 000000000..3892f3b54
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/bytes_appengine.go
@@ -0,0 +1,7 @@
+// +build appengine
+
+package bigcache
+
+func bytesToString(b []byte) string {
+	return string(b)
+}
diff --git a/vendor/github.com/allegro/bigcache/clock.go b/vendor/github.com/allegro/bigcache/clock.go
new file mode 100644
index 000000000..f8b535e13
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/clock.go
@@ -0,0 +1,14 @@
+package bigcache
+
+import "time"
+
+type clock interface {
+	epoch() int64
+}
+
+type systemClock struct {
+}
+
+func (c systemClock) epoch() int64 {
+	return time.Now().Unix()
+}
diff --git a/vendor/github.com/allegro/bigcache/config.go b/vendor/github.com/allegro/bigcache/config.go
new file mode 100644
index 000000000..9654143ab
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/config.go
@@ -0,0 +1,86 @@
+package bigcache
+
+import "time"
+
+// Config for BigCache
+type Config struct {
+	// Number of cache shards, value must be a power of two
+	Shards int
+	// Time after which entry can be evicted
+	LifeWindow time.Duration
+	// Interval between removing expired entries (clean up).
+	// If set to <= 0 then no action is performed. Setting to < 1 second is counterproductive — bigcache has a one second resolution.
+	CleanWindow time.Duration
+	// Max number of entries in life window. Used only to calculate initial size for cache shards.
+	// When proper value is set then additional memory allocation does not occur.
+	MaxEntriesInWindow int
+	// Max size of entry in bytes. Used only to calculate initial size for cache shards.
+	MaxEntrySize int
+	// Verbose mode prints information about new memory allocation
+	Verbose bool
+	// Hasher used to map between string keys and unsigned 64bit integers, by default fnv64 hashing is used.
+	Hasher Hasher
+	// HardMaxCacheSize is a limit for cache size in MB. Cache will not allocate more memory than this limit.
+	// It can protect application from consuming all available memory on machine, therefore from running OOM Killer.
+	// Default value is 0 which means unlimited size. When the limit is higher than 0 and reached then
+	// the oldest entries are overridden for the new ones.
+	HardMaxCacheSize int
+	// OnRemove is a callback fired when the oldest entry is removed because of its expiration time or no space left
+	// for the new entry, or because delete was called.
+	// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
+	OnRemove func(key string, entry []byte)
+	// OnRemoveWithReason is a callback fired when the oldest entry is removed because of its expiration time or no space left
+	// for the new entry, or because delete was called. A constant representing the reason will be passed through.
+	// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
+	// Ignored if OnRemove is specified.
+	OnRemoveWithReason func(key string, entry []byte, reason RemoveReason)
+
+	onRemoveFilter int
+
+	// Logger is a logging interface and used in combination with `Verbose`
+	// Defaults to `DefaultLogger()`
+	Logger Logger
+}
+
+// DefaultConfig initializes config with default values.
+// When load for BigCache can be predicted in advance then it is better to use custom config.
+func DefaultConfig(eviction time.Duration) Config {
+	return Config{
+		Shards:             1024,
+		LifeWindow:         eviction,
+		CleanWindow:        0,
+		MaxEntriesInWindow: 1000 * 10 * 60,
+		MaxEntrySize:       500,
+		Verbose:            true,
+		Hasher:             newDefaultHasher(),
+		HardMaxCacheSize:   0,
+		Logger:             DefaultLogger(),
+	}
+}
+
+// initialShardSize computes initial shard size
+func (c Config) initialShardSize() int {
+	return max(c.MaxEntriesInWindow/c.Shards, minimumEntriesInShard)
+}
+
+// maximumShardSize computes maximum shard size
+func (c Config) maximumShardSize() int {
+	maxShardSize := 0
+
+	if c.HardMaxCacheSize > 0 {
+		maxShardSize = convertMBToBytes(c.HardMaxCacheSize) / c.Shards
+	}
+
+	return maxShardSize
+}
+
+// OnRemoveFilterSet sets which remove reasons will trigger a call to OnRemoveWithReason.
+// Filtering out reasons prevents bigcache from unwrapping them, which saves cpu.
+func (c Config) OnRemoveFilterSet(reasons ...RemoveReason) Config {
+	c.onRemoveFilter = 0
+	for i := range reasons {
+		c.onRemoveFilter |= 1 << uint(reasons[i])
+	}
+
+	return c
+}
diff --git a/vendor/github.com/allegro/bigcache/encoding.go b/vendor/github.com/allegro/bigcache/encoding.go
new file mode 100644
index 000000000..4d434e5dc
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/encoding.go
@@ -0,0 +1,62 @@
+package bigcache
+
+import (
+	"encoding/binary"
+)
+
+const (
+	timestampSizeInBytes = 8                                                       // Number of bytes used for timestamp
+	hashSizeInBytes      = 8                                                       // Number of bytes used for hash
+	keySizeInBytes       = 2                                                       // Number of bytes used for size of entry key
+	headersSizeInBytes   = timestampSizeInBytes + hashSizeInBytes + keySizeInBytes // Number of bytes used for all headers
+)
+
+func wrapEntry(timestamp uint64, hash uint64, key string, entry []byte, buffer *[]byte) []byte {
+	keyLength := len(key)
+	blobLength := len(entry) + headersSizeInBytes + keyLength
+
+	if blobLength > len(*buffer) {
+		*buffer = make([]byte, blobLength)
+	}
+	blob := *buffer
+
+	binary.LittleEndian.PutUint64(blob, timestamp)
+	binary.LittleEndian.PutUint64(blob[timestampSizeInBytes:], hash)
+	binary.LittleEndian.PutUint16(blob[timestampSizeInBytes+hashSizeInBytes:], uint16(keyLength))
+	copy(blob[headersSizeInBytes:], key)
+	copy(blob[headersSizeInBytes+keyLength:], entry)
+
+	return blob[:blobLength]
+}
+
+func readEntry(data []byte) []byte {
+	length := binary.LittleEndian.Uint16(data[timestampSizeInBytes+hashSizeInBytes:])
+
+	// copy on read
+	dst := make([]byte, len(data)-int(headersSizeInBytes+length))
+	copy(dst, data[headersSizeInBytes+length:])
+
+	return dst
+}
+
+func readTimestampFromEntry(data []byte) uint64 {
+	return binary.LittleEndian.Uint64(data)
+}
+
+func readKeyFromEntry(data []byte) string {
+	length := binary.LittleEndian.Uint16(data[timestampSizeInBytes+hashSizeInBytes:])
+
+	// copy on read
+	dst := make([]byte, length)
+	copy(dst, data[headersSizeInBytes:headersSizeInBytes+length])
+
+	return bytesToString(dst)
+}
+
+func readHashFromEntry(data []byte) uint64 {
+	return binary.LittleEndian.Uint64(data[timestampSizeInBytes:])
+}
+
+func resetKeyFromEntry(data []byte) {
+	binary.LittleEndian.PutUint64(data[timestampSizeInBytes:], 0)
+}
diff --git a/vendor/github.com/allegro/bigcache/entry_not_found_error.go b/vendor/github.com/allegro/bigcache/entry_not_found_error.go
new file mode 100644
index 000000000..883bdc29e
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/entry_not_found_error.go
@@ -0,0 +1,17 @@
+package bigcache
+
+import "fmt"
+
+// EntryNotFoundError is an error type struct which is returned when entry was not found for provided key
+type EntryNotFoundError struct {
+	key string
+}
+
+func notFound(key string) error {
+	return &EntryNotFoundError{key}
+}
+
+// Error returned when entry does not exist.
+func (e EntryNotFoundError) Error() string {
+	return fmt.Sprintf("Entry %q not found", e.key)
+}
diff --git a/vendor/github.com/allegro/bigcache/fnv.go b/vendor/github.com/allegro/bigcache/fnv.go
new file mode 100644
index 000000000..188c9aa6d
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/fnv.go
@@ -0,0 +1,28 @@
+package bigcache
+
+// newDefaultHasher returns a new 64-bit FNV-1a Hasher which makes no memory allocations.
+// Its Sum64 method will lay the value out in big-endian byte order.
+// See https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function
+func newDefaultHasher() Hasher {
+	return fnv64a{}
+}
+
+type fnv64a struct{}
+
+const (
+	// offset64 FNVa offset basis. See https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function#FNV-1a_hash
+	offset64 = 14695981039346656037
+	// prime64 FNVa prime value. See https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function#FNV-1a_hash
+	prime64 = 1099511628211
+)
+
+// Sum64 gets the string and returns its uint64 hash value.
+func (f fnv64a) Sum64(key string) uint64 {
+	var hash uint64 = offset64
+	for i := 0; i < len(key); i++ {
+		hash ^= uint64(key[i])
+		hash *= prime64
+	}
+
+	return hash
+}
diff --git a/vendor/github.com/allegro/bigcache/hash.go b/vendor/github.com/allegro/bigcache/hash.go
new file mode 100644
index 000000000..5f8ade774
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/hash.go
@@ -0,0 +1,8 @@
+package bigcache
+
+// Hasher is responsible for generating unsigned, 64 bit hash of provided string. Hasher should minimize collisions
+// (generating same hash for different strings) and while performance is also important fast functions are preferable (i.e.
+// you can use FarmHash family).
+type Hasher interface {
+	Sum64(string) uint64
+}
diff --git a/vendor/github.com/allegro/bigcache/iterator.go b/vendor/github.com/allegro/bigcache/iterator.go
new file mode 100644
index 000000000..70b98d900
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/iterator.go
@@ -0,0 +1,122 @@
+package bigcache
+
+import "sync"
+
+type iteratorError string
+
+func (e iteratorError) Error() string {
+	return string(e)
+}
+
+// ErrInvalidIteratorState is reported when iterator is in invalid state
+const ErrInvalidIteratorState = iteratorError("Iterator is in invalid state. Use SetNext() to move to next position")
+
+// ErrCannotRetrieveEntry is reported when entry cannot be retrieved from underlying
+const ErrCannotRetrieveEntry = iteratorError("Could not retrieve entry from cache")
+
+var emptyEntryInfo = EntryInfo{}
+
+// EntryInfo holds informations about entry in the cache
+type EntryInfo struct {
+	timestamp uint64
+	hash      uint64
+	key       string
+	value     []byte
+}
+
+// Key returns entry's underlying key
+func (e EntryInfo) Key() string {
+	return e.key
+}
+
+// Hash returns entry's hash value
+func (e EntryInfo) Hash() uint64 {
+	return e.hash
+}
+
+// Timestamp returns entry's timestamp (time of insertion)
+func (e EntryInfo) Timestamp() uint64 {
+	return e.timestamp
+}
+
+// Value returns entry's underlying value
+func (e EntryInfo) Value() []byte {
+	return e.value
+}
+
+// EntryInfoIterator allows to iterate over entries in the cache
+type EntryInfoIterator struct {
+	mutex         sync.Mutex
+	cache         *BigCache
+	currentShard  int
+	currentIndex  int
+	elements      []uint32
+	elementsCount int
+	valid         bool
+}
+
+// SetNext moves to next element and returns true if it exists.
+func (it *EntryInfoIterator) SetNext() bool {
+	it.mutex.Lock()
+
+	it.valid = false
+	it.currentIndex++
+
+	if it.elementsCount > it.currentIndex {
+		it.valid = true
+		it.mutex.Unlock()
+		return true
+	}
+
+	for i := it.currentShard + 1; i < it.cache.config.Shards; i++ {
+		it.elements, it.elementsCount = it.cache.shards[i].copyKeys()
+
+		// Non empty shard - stick with it
+		if it.elementsCount > 0 {
+			it.currentIndex = 0
+			it.currentShard = i
+			it.valid = true
+			it.mutex.Unlock()
+			return true
+		}
+	}
+	it.mutex.Unlock()
+	return false
+}
+
+func newIterator(cache *BigCache) *EntryInfoIterator {
+	elements, count := cache.shards[0].copyKeys()
+
+	return &EntryInfoIterator{
+		cache:         cache,
+		currentShard:  0,
+		currentIndex:  -1,
+		elements:      elements,
+		elementsCount: count,
+	}
+}
+
+// Value returns current value from the iterator
+func (it *EntryInfoIterator) Value() (EntryInfo, error) {
+	it.mutex.Lock()
+
+	if !it.valid {
+		it.mutex.Unlock()
+		return emptyEntryInfo, ErrInvalidIteratorState
+	}
+
+	entry, err := it.cache.shards[it.currentShard].getEntry(int(it.elements[it.currentIndex]))
+
+	if err != nil {
+		it.mutex.Unlock()
+		return emptyEntryInfo, ErrCannotRetrieveEntry
+	}
+	it.mutex.Unlock()
+
+	return EntryInfo{
+		timestamp: readTimestampFromEntry(entry),
+		hash:      readHashFromEntry(entry),
+		key:       readKeyFromEntry(entry),
+		value:     readEntry(entry),
+	}, nil
+}
diff --git a/vendor/github.com/allegro/bigcache/logger.go b/vendor/github.com/allegro/bigcache/logger.go
new file mode 100644
index 000000000..50e84abc8
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/logger.go
@@ -0,0 +1,30 @@
+package bigcache
+
+import (
+	"log"
+	"os"
+)
+
+// Logger is invoked when `Config.Verbose=true`
+type Logger interface {
+	Printf(format string, v ...interface{})
+}
+
+// this is a safeguard, breaking on compile time in case
+// `log.Logger` does not adhere to our `Logger` interface.
+// see https://golang.org/doc/faq#guarantee_satisfies_interface
+var _ Logger = &log.Logger{}
+
+// DefaultLogger returns a `Logger` implementation
+// backed by stdlib's log
+func DefaultLogger() *log.Logger {
+	return log.New(os.Stdout, "", log.LstdFlags)
+}
+
+func newLogger(custom Logger) Logger {
+	if custom != nil {
+		return custom
+	}
+
+	return DefaultLogger()
+}
diff --git a/vendor/github.com/allegro/bigcache/queue/bytes_queue.go b/vendor/github.com/allegro/bigcache/queue/bytes_queue.go
new file mode 100644
index 000000000..0285c72cd
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/queue/bytes_queue.go
@@ -0,0 +1,210 @@
+package queue
+
+import (
+	"encoding/binary"
+	"log"
+	"time"
+)
+
+const (
+	// Number of bytes used to keep information about entry size
+	headerEntrySize = 4
+	// Bytes before left margin are not used. Zero index means element does not exist in queue, useful while reading slice from index
+	leftMarginIndex = 1
+	// Minimum empty blob size in bytes. Empty blob fills space between tail and head in additional memory allocation.
+	// It keeps entries indexes unchanged
+	minimumEmptyBlobSize = 32 + headerEntrySize
+)
+
+// BytesQueue is a non-thread safe queue type of fifo based on bytes array.
+// For every push operation index of entry is returned. It can be used to read the entry later
+type BytesQueue struct {
+	array           []byte
+	capacity        int
+	maxCapacity     int
+	head            int
+	tail            int
+	count           int
+	rightMargin     int
+	headerBuffer    []byte
+	verbose         bool
+	initialCapacity int
+}
+
+type queueError struct {
+	message string
+}
+
+// NewBytesQueue initialize new bytes queue.
+// Initial capacity is used in bytes array allocation
+// When verbose flag is set then information about memory allocation are printed
+func NewBytesQueue(initialCapacity int, maxCapacity int, verbose bool) *BytesQueue {
+	return &BytesQueue{
+		array:           make([]byte, initialCapacity),
+		capacity:        initialCapacity,
+		maxCapacity:     maxCapacity,
+		headerBuffer:    make([]byte, headerEntrySize),
+		tail:            leftMarginIndex,
+		head:            leftMarginIndex,
+		rightMargin:     leftMarginIndex,
+		verbose:         verbose,
+		initialCapacity: initialCapacity,
+	}
+}
+
+// Reset removes all entries from queue
+func (q *BytesQueue) Reset() {
+	// Just reset indexes
+	q.tail = leftMarginIndex
+	q.head = leftMarginIndex
+	q.rightMargin = leftMarginIndex
+	q.count = 0
+}
+
+// Push copies entry at the end of queue and moves tail pointer. Allocates more space if needed.
+// Returns index for pushed data or error if maximum size queue limit is reached.
+func (q *BytesQueue) Push(data []byte) (int, error) {
+	dataLen := len(data)
+
+	if q.availableSpaceAfterTail() < dataLen+headerEntrySize {
+		if q.availableSpaceBeforeHead() >= dataLen+headerEntrySize {
+			q.tail = leftMarginIndex
+		} else if q.capacity+headerEntrySize+dataLen >= q.maxCapacity && q.maxCapacity > 0 {
+			return -1, &queueError{"Full queue. Maximum size limit reached."}
+		} else {
+			q.allocateAdditionalMemory(dataLen + headerEntrySize)
+		}
+	}
+
+	index := q.tail
+
+	q.push(data, dataLen)
+
+	return index, nil
+}
+
+func (q *BytesQueue) allocateAdditionalMemory(minimum int) {
+	start := time.Now()
+	if q.capacity < minimum {
+		q.capacity += minimum
+	}
+	q.capacity = q.capacity * 2
+	if q.capacity > q.maxCapacity && q.maxCapacity > 0 {
+		q.capacity = q.maxCapacity
+	}
+
+	oldArray := q.array
+	q.array = make([]byte, q.capacity)
+
+	if leftMarginIndex != q.rightMargin {
+		copy(q.array, oldArray[:q.rightMargin])
+
+		if q.tail < q.head {
+			emptyBlobLen := q.head - q.tail - headerEntrySize
+			q.push(make([]byte, emptyBlobLen), emptyBlobLen)
+			q.head = leftMarginIndex
+			q.tail = q.rightMargin
+		}
+	}
+
+	if q.verbose {
+		log.Printf("Allocated new queue in %s; Capacity: %d \n", time.Since(start), q.capacity)
+	}
+}
+
+func (q *BytesQueue) push(data []byte, len int) {
+	binary.LittleEndian.PutUint32(q.headerBuffer, uint32(len))
+	q.copy(q.headerBuffer, headerEntrySize)
+
+	q.copy(data, len)
+
+	if q.tail > q.head {
+		q.rightMargin = q.tail
+	}
+
+	q.count++
+}
+
+func (q *BytesQueue) copy(data []byte, len int) {
+	q.tail += copy(q.array[q.tail:], data[:len])
+}
+
+// Pop reads the oldest entry from queue and moves head pointer to the next one
+func (q *BytesQueue) Pop() ([]byte, error) {
+	data, size, err := q.peek(q.head)
+	if err != nil {
+		return nil, err
+	}
+
+	q.head += headerEntrySize + size
+	q.count--
+
+	if q.head == q.rightMargin {
+		q.head = leftMarginIndex
+		if q.tail == q.rightMargin {
+			q.tail = leftMarginIndex
+		}
+		q.rightMargin = q.tail
+	}
+
+	return data, nil
+}
+
+// Peek reads the oldest entry from list without moving head pointer
+func (q *BytesQueue) Peek() ([]byte, error) {
+	data, _, err := q.peek(q.head)
+	return data, err
+}
+
+// Get reads entry from index
+func (q *BytesQueue) Get(index int) ([]byte, error) {
+	data, _, err := q.peek(index)
+	return data, err
+}
+
+// Capacity returns number of allocated bytes for queue
+func (q *BytesQueue) Capacity() int {
+	return q.capacity
+}
+
+// Len returns number of entries kept in queue
+func (q *BytesQueue) Len() int {
+	return q.count
+}
+
+// Error returns error message
+func (e *queueError) Error() string {
+	return e.message
+}
+
+func (q *BytesQueue) peek(index int) ([]byte, int, error) {
+
+	if q.count == 0 {
+		return nil, 0, &queueError{"Empty queue"}
+	}
+
+	if index <= 0 {
+		return nil, 0, &queueError{"Index must be grater than zero. Invalid index."}
+	}
+
+	if index+headerEntrySize >= len(q.array) {
+		return nil, 0, &queueError{"Index out of range"}
+	}
+
+	blockSize := int(binary.LittleEndian.Uint32(q.array[index : index+headerEntrySize]))
+	return q.array[index+headerEntrySize : index+headerEntrySize+blockSize], blockSize, nil
+}
+
+func (q *BytesQueue) availableSpaceAfterTail() int {
+	if q.tail >= q.head {
+		return q.capacity - q.tail
+	}
+	return q.head - q.tail - minimumEmptyBlobSize
+}
+
+func (q *BytesQueue) availableSpaceBeforeHead() int {
+	if q.tail >= q.head {
+		return q.head - leftMarginIndex - minimumEmptyBlobSize
+	}
+	return q.head - q.tail - minimumEmptyBlobSize
+}
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()),
+	}
+}
diff --git a/vendor/github.com/allegro/bigcache/stats.go b/vendor/github.com/allegro/bigcache/stats.go
new file mode 100644
index 000000000..07157132a
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/stats.go
@@ -0,0 +1,15 @@
+package bigcache
+
+// Stats stores cache statistics
+type Stats struct {
+	// Hits is a number of successfully found keys
+	Hits int64 `json:"hits"`
+	// Misses is a number of not found keys
+	Misses int64 `json:"misses"`
+	// DelHits is a number of successfully deleted keys
+	DelHits int64 `json:"delete_hits"`
+	// DelMisses is a number of not deleted keys
+	DelMisses int64 `json:"delete_misses"`
+	// Collisions is a number of happened key-collisions
+	Collisions int64 `json:"collisions"`
+}
diff --git a/vendor/github.com/allegro/bigcache/utils.go b/vendor/github.com/allegro/bigcache/utils.go
new file mode 100644
index 000000000..ca1df79b9
--- /dev/null
+++ b/vendor/github.com/allegro/bigcache/utils.go
@@ -0,0 +1,16 @@
+package bigcache
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func convertMBToBytes(value int) int {
+	return value * 1024 * 1024
+}
+
+func isPowerOfTwo(number int) bool {
+	return (number & (number - 1)) == 0
+}
diff --git a/vendor/vendor.json b/vendor/vendor.json
index 06268535e..1bfe09da7 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -39,6 +39,18 @@
 			"revisionTime": "2018-01-16T20:38:02Z"
 		},
 		{
+			"checksumSHA1": "9Niiu1GNhWUrXnGZrl8AU4EzbVE=",
+			"path": "github.com/allegro/bigcache",
+			"revision": "bff00e20c68d9f136477d62d182a7dc917bae0ca",
+			"revisionTime": "2018-10-22T20:06:25Z"
+		},
+		{
+			"checksumSHA1": "zqToN+R6KybEskp1D4G/lAOKXU4=",
+			"path": "github.com/allegro/bigcache/queue",
+			"revision": "bff00e20c68d9f136477d62d182a7dc917bae0ca",
+			"revisionTime": "2018-10-22T20:06:25Z"
+		},
+		{
 			"checksumSHA1": "USkefO0g1U9mr+8hagv3fpSkrxg=",
 			"path": "github.com/aristanetworks/goarista/monotime",
 			"revision": "ea17b1a17847fb6e4c0a91de0b674704693469b0",