diff options
Diffstat (limited to 'vendor/github.com/golang/groupcache')
| -rw-r--r-- | vendor/github.com/golang/groupcache/LICENSE | 191 | ||||
| -rw-r--r-- | vendor/github.com/golang/groupcache/README.md | 73 | ||||
| -rw-r--r-- | vendor/github.com/golang/groupcache/lru/lru.go | 133 |
3 files changed, 397 insertions, 0 deletions
diff --git a/vendor/github.com/golang/groupcache/LICENSE b/vendor/github.com/golang/groupcache/LICENSE new file mode 100644 index 000000000..37ec93a14 --- /dev/null +++ b/vendor/github.com/golang/groupcache/LICENSE @@ -0,0 +1,191 @@ +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: + +You must give any other recipients of the Work or Derivative Works a copy of +this License; and +You must cause any modified files to carry prominent notices stating that You +changed the files; and +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 +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/golang/groupcache/README.md b/vendor/github.com/golang/groupcache/README.md new file mode 100644 index 000000000..70c29da16 --- /dev/null +++ b/vendor/github.com/golang/groupcache/README.md @@ -0,0 +1,73 @@ +# groupcache + +## Summary + +groupcache is a caching and cache-filling library, intended as a +replacement for memcached in many cases. + +For API docs and examples, see http://godoc.org/github.com/golang/groupcache + +## Comparison to memcached + +### **Like memcached**, groupcache: + + * shards by key to select which peer is responsible for that key + +### **Unlike memcached**, groupcache: + + * does not require running a separate set of servers, thus massively + reducing deployment/configuration pain. groupcache is a client + library as well as a server. It connects to its own peers. + + * comes with a cache filling mechanism. Whereas memcached just says + "Sorry, cache miss", often resulting in a thundering herd of + database (or whatever) loads from an unbounded number of clients + (which has resulted in several fun outages), groupcache coordinates + cache fills such that only one load in one process of an entire + replicated set of processes populates the cache, then multiplexes + the loaded value to all callers. + + * does not support versioned values. If key "foo" is value "bar", + key "foo" must always be "bar". There are neither cache expiration + times, nor explicit cache evictions. Thus there is also no CAS, + nor Increment/Decrement. This also means that groupcache.... + + * ... supports automatic mirroring of super-hot items to multiple + processes. This prevents memcached hot spotting where a machine's + CPU and/or NIC are overloaded by very popular keys/values. + + * is currently only available for Go. It's very unlikely that I + (bradfitz@) will port the code to any other language. + +## Loading process + +In a nutshell, a groupcache lookup of **Get("foo")** looks like: + +(On machine #5 of a set of N machines running the same code) + + 1. Is the value of "foo" in local memory because it's super hot? If so, use it. + + 2. Is the value of "foo" in local memory because peer #5 (the current + peer) is the owner of it? If so, use it. + + 3. Amongst all the peers in my set of N, am I the owner of the key + "foo"? (e.g. does it consistent hash to 5?) If so, load it. If + other callers come in, via the same process or via RPC requests + from peers, they block waiting for the load to finish and get the + same answer. If not, RPC to the peer that's the owner and get + the answer. If the RPC fails, just load it locally (still with + local dup suppression). + +## Users + +groupcache is in production use by dl.google.com (its original user), +parts of Blogger, parts of Google Code, parts of Google Fiber, parts +of Google production monitoring systems, etc. + +## Presentations + +See http://talks.golang.org/2013/oscon-dl.slide + +## Help + +Use the golang-nuts mailing list for any discussion or questions. diff --git a/vendor/github.com/golang/groupcache/lru/lru.go b/vendor/github.com/golang/groupcache/lru/lru.go new file mode 100644 index 000000000..532cc45e6 --- /dev/null +++ b/vendor/github.com/golang/groupcache/lru/lru.go @@ -0,0 +1,133 @@ +/* +Copyright 2013 Google Inc. + +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. +*/ + +// Package lru implements an LRU cache. +package lru + +import "container/list" + +// Cache is an LRU cache. It is not safe for concurrent access. +type Cache struct { + // MaxEntries is the maximum number of cache entries before + // an item is evicted. Zero means no limit. + MaxEntries int + + // OnEvicted optionally specificies a callback function to be + // executed when an entry is purged from the cache. + OnEvicted func(key Key, value interface{}) + + ll *list.List + cache map[interface{}]*list.Element +} + +// A Key may be any value that is comparable. See http://golang.org/ref/spec#Comparison_operators +type Key interface{} + +type entry struct { + key Key + value interface{} +} + +// New creates a new Cache. +// If maxEntries is zero, the cache has no limit and it's assumed +// that eviction is done by the caller. +func New(maxEntries int) *Cache { + return &Cache{ + MaxEntries: maxEntries, + ll: list.New(), + cache: make(map[interface{}]*list.Element), + } +} + +// Add adds a value to the cache. +func (c *Cache) Add(key Key, value interface{}) { + if c.cache == nil { + c.cache = make(map[interface{}]*list.Element) + c.ll = list.New() + } + if ee, ok := c.cache[key]; ok { + c.ll.MoveToFront(ee) + ee.Value.(*entry).value = value + return + } + ele := c.ll.PushFront(&entry{key, value}) + c.cache[key] = ele + if c.MaxEntries != 0 && c.ll.Len() > c.MaxEntries { + c.RemoveOldest() + } +} + +// Get looks up a key's value from the cache. +func (c *Cache) Get(key Key) (value interface{}, ok bool) { + if c.cache == nil { + return + } + if ele, hit := c.cache[key]; hit { + c.ll.MoveToFront(ele) + return ele.Value.(*entry).value, true + } + return +} + +// Remove removes the provided key from the cache. +func (c *Cache) Remove(key Key) { + if c.cache == nil { + return + } + if ele, hit := c.cache[key]; hit { + c.removeElement(ele) + } +} + +// RemoveOldest removes the oldest item from the cache. +func (c *Cache) RemoveOldest() { + if c.cache == nil { + return + } + ele := c.ll.Back() + if ele != nil { + c.removeElement(ele) + } +} + +func (c *Cache) removeElement(e *list.Element) { + c.ll.Remove(e) + kv := e.Value.(*entry) + delete(c.cache, kv.key) + if c.OnEvicted != nil { + c.OnEvicted(kv.key, kv.value) + } +} + +// Len returns the number of items in the cache. +func (c *Cache) Len() int { + if c.cache == nil { + return 0 + } + return c.ll.Len() +} + +// Clear purges all stored items from the cache. +func (c *Cache) Clear() { + if c.OnEvicted != nil { + for _, e := range c.cache { + kv := e.Value.(*entry) + c.OnEvicted(kv.key, kv.value) + } + } + c.ll = nil + c.cache = nil +} |