diff options
Diffstat (limited to 'vendor/github.com/hashicorp')
| -rw-r--r-- | vendor/github.com/hashicorp/golang-lru/2q.go | 212 | ||||
| -rw-r--r-- | vendor/github.com/hashicorp/golang-lru/LICENSE | 362 | ||||
| -rw-r--r-- | vendor/github.com/hashicorp/golang-lru/arc.go | 257 | ||||
| -rw-r--r-- | vendor/github.com/hashicorp/golang-lru/lru.go | 114 | ||||
| -rw-r--r-- | vendor/github.com/hashicorp/golang-lru/simplelru/lru.go | 160 |
5 files changed, 1105 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/golang-lru/2q.go b/vendor/github.com/hashicorp/golang-lru/2q.go new file mode 100644 index 00000000..337d9632 --- /dev/null +++ b/vendor/github.com/hashicorp/golang-lru/2q.go @@ -0,0 +1,212 @@ +package lru + +import ( + "fmt" + "sync" + + "github.com/hashicorp/golang-lru/simplelru" +) + +const ( + // Default2QRecentRatio is the ratio of the 2Q cache dedicated + // to recently added entries that have only been accessed once. + Default2QRecentRatio = 0.25 + + // Default2QGhostEntries is the default ratio of ghost + // entries kept to track entries recently evicted + Default2QGhostEntries = 0.50 +) + +// TwoQueueCache is a thread-safe fixed size 2Q cache. +// 2Q is an enhancement over the standard LRU cache +// in that it tracks both frequently and recently used +// entries separately. This avoids a burst in access to new +// entries from evicting frequently used entries. It adds some +// additional tracking overhead to the standard LRU cache, and is +// computationally about 2x the cost, and adds some metadata over +// head. The ARCCache is similar, but does not require setting any +// parameters. +type TwoQueueCache struct { + size int + recentSize int + + recent *simplelru.LRU + frequent *simplelru.LRU + recentEvict *simplelru.LRU + lock sync.RWMutex +} + +// New2Q creates a new TwoQueueCache using the default +// values for the parameters. +func New2Q(size int) (*TwoQueueCache, error) { + return New2QParams(size, Default2QRecentRatio, Default2QGhostEntries) +} + +// New2QParams creates a new TwoQueueCache using the provided +// parameter values. +func New2QParams(size int, recentRatio float64, ghostRatio float64) (*TwoQueueCache, error) { + if size <= 0 { + return nil, fmt.Errorf("invalid size") + } + if recentRatio < 0.0 || recentRatio > 1.0 { + return nil, fmt.Errorf("invalid recent ratio") + } + if ghostRatio < 0.0 || ghostRatio > 1.0 { + return nil, fmt.Errorf("invalid ghost ratio") + } + + // Determine the sub-sizes + recentSize := int(float64(size) * recentRatio) + evictSize := int(float64(size) * ghostRatio) + + // Allocate the LRUs + recent, err := simplelru.NewLRU(size, nil) + if err != nil { + return nil, err + } + frequent, err := simplelru.NewLRU(size, nil) + if err != nil { + return nil, err + } + recentEvict, err := simplelru.NewLRU(evictSize, nil) + if err != nil { + return nil, err + } + + // Initialize the cache + c := &TwoQueueCache{ + size: size, + recentSize: recentSize, + recent: recent, + frequent: frequent, + recentEvict: recentEvict, + } + return c, nil +} + +func (c *TwoQueueCache) Get(key interface{}) (interface{}, bool) { + c.lock.Lock() + defer c.lock.Unlock() + + // Check if this is a frequent value + if val, ok := c.frequent.Get(key); ok { + return val, ok + } + + // If the value is contained in recent, then we + // promote it to frequent + if val, ok := c.recent.Peek(key); ok { + c.recent.Remove(key) + c.frequent.Add(key, val) + return val, ok + } + + // No hit + return nil, false +} + +func (c *TwoQueueCache) Add(key, value interface{}) { + c.lock.Lock() + defer c.lock.Unlock() + + // Check if the value is frequently used already, + // and just update the value + if c.frequent.Contains(key) { + c.frequent.Add(key, value) + return + } + + // Check if the value is recently used, and promote + // the value into the frequent list + if c.recent.Contains(key) { + c.recent.Remove(key) + c.frequent.Add(key, value) + return + } + + // If the value was recently evicted, add it to the + // frequently used list + if c.recentEvict.Contains(key) { + c.ensureSpace(true) + c.recentEvict.Remove(key) + c.frequent.Add(key, value) + return + } + + // Add to the recently seen list + c.ensureSpace(false) + c.recent.Add(key, value) + return +} + +// ensureSpace is used to ensure we have space in the cache +func (c *TwoQueueCache) ensureSpace(recentEvict bool) { + // If we have space, nothing to do + recentLen := c.recent.Len() + freqLen := c.frequent.Len() + if recentLen+freqLen < c.size { + return + } + + // If the recent buffer is larger than + // the target, evict from there + if recentLen > 0 && (recentLen > c.recentSize || (recentLen == c.recentSize && !recentEvict)) { + k, _, _ := c.recent.RemoveOldest() + c.recentEvict.Add(k, nil) + return + } + + // Remove from the frequent list otherwise + c.frequent.RemoveOldest() +} + +func (c *TwoQueueCache) Len() int { + c.lock.RLock() + defer c.lock.RUnlock() + return c.recent.Len() + c.frequent.Len() +} + +func (c *TwoQueueCache) Keys() []interface{} { + c.lock.RLock() + defer c.lock.RUnlock() + k1 := c.frequent.Keys() + k2 := c.recent.Keys() + return append(k1, k2...) +} + +func (c *TwoQueueCache) Remove(key interface{}) { + c.lock.Lock() + defer c.lock.Unlock() + if c.frequent.Remove(key) { + return + } + if c.recent.Remove(key) { + return + } + if c.recentEvict.Remove(key) { + return + } +} + +func (c *TwoQueueCache) Purge() { + c.lock.Lock() + defer c.lock.Unlock() + c.recent.Purge() + c.frequent.Purge() + c.recentEvict.Purge() +} + +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) { + c.lock.RLock() + defer c.lock.RUnlock() + if val, ok := c.frequent.Peek(key); ok { + return val, ok + } + return c.recent.Peek(key) +} diff --git a/vendor/github.com/hashicorp/golang-lru/LICENSE b/vendor/github.com/hashicorp/golang-lru/LICENSE new file mode 100644 index 00000000..be2cc4df --- /dev/null +++ b/vendor/github.com/hashicorp/golang-lru/LICENSE @@ -0,0 +1,362 @@ +Mozilla Public License, version 2.0 + +1. Definitions + +1.1. "Contributor" + + means each individual or legal entity that creates, contributes to the + creation of, or owns Covered Software. + +1.2. "Contributor Version" + + means the combination of the Contributions of others (if any) used by a + Contributor and that particular Contributor's Contribution. + +1.3. "Contribution" + + means Covered Software of a particular Contributor. + +1.4. "Covered Software" + + means Source Code Form to which the initial Contributor has attached the + notice in Exhibit A, the Executable Form of such Source Code Form, and + Modifications of such Source Code Form, in each case including portions + thereof. + +1.5. "Incompatible With Secondary Licenses" + means + + a. that the initial Contributor has attached the notice described in + Exhibit B to the Covered Software; or + + b. that the Covered Software was made available under the terms of + version 1.1 or earlier of the License, but not also under the terms of + a Secondary License. + +1.6. "Executable Form" + + means any form of the work other than Source Code Form. + +1.7. "Larger Work" + + means a work that combines Covered Software with other material, in a + separate file or files, that is not Covered Software. + +1.8. "License" + + means this document. + +1.9. "Licensable" + + means having the right to grant, to the maximum extent possible, whether + at the time of the initial grant or subsequently, any and all of the + rights conveyed by this License. + +1.10. "Modifications" + + means any of the following: + + a. any file in Source Code Form that results from an addition to, + deletion from, or modification of the contents of Covered Software; or + + b. any new file in Source Code Form that contains any Covered Software. + +1.11. "Patent Claims" of a Contributor + + means any patent claim(s), including without limitation, method, + process, and apparatus claims, in any patent Licensable by such + Contributor that would be infringed, but for the grant of the License, + by the making, using, selling, offering for sale, having made, import, + or transfer of either its Contributions or its Contributor Version. + +1.12. "Secondary License" + + means either the GNU General Public License, Version 2.0, the GNU Lesser + General Public License, Version 2.1, the GNU Affero General Public + License, Version 3.0, or any later versions of those licenses. + +1.13. "Source Code Form" + + means the form of the work preferred for making modifications. + +1.14. "You" (or "Your") + + means an individual or a legal entity exercising rights under this + License. For legal entities, "You" includes any entity that controls, is + controlled by, or is under common control with You. For purposes of this + definition, "control" means (a) the power, direct or indirect, to cause + the direction or management of such entity, whether by contract or + otherwise, or (b) ownership of more than fifty percent (50%) of the + outstanding shares or beneficial ownership of such entity. + + +2. License Grants and Conditions + +2.1. Grants + + Each Contributor hereby grants You a world-wide, royalty-free, + non-exclusive license: + + a. under intellectual property rights (other than patent or trademark) + Licensable by such Contributor to use, reproduce, make available, + modify, display, perform, distribute, and otherwise exploit its + Contributions, either on an unmodified basis, with Modifications, or + as part of a Larger Work; and + + b. under Patent Claims of such Contributor to make, use, sell, offer for + sale, have made, import, and otherwise transfer either its + Contributions or its Contributor Version. + +2.2. Effective Date + + The licenses granted in Section 2.1 with respect to any Contribution + become effective for each Contribution on the date the Contributor first + distributes such Contribution. + +2.3. Limitations on Grant Scope + + The licenses granted in this Section 2 are the only rights granted under + this License. No additional rights or licenses will be implied from the + distribution or licensing of Covered Software under this License. + Notwithstanding Section 2.1(b) above, no patent license is granted by a + Contributor: + + a. for any code that a Contributor has removed from Covered Software; or + + b. for infringements caused by: (i) Your and any other third party's + modifications of Covered Software, or (ii) the combination of its + Contributions with other software (except as part of its Contributor + Version); or + + c. under Patent Claims infringed by Covered Software in the absence of + its Contributions. + + This License does not grant any rights in the trademarks, service marks, + or logos of any Contributor (except as may be necessary to comply with + the notice requirements in Section 3.4). + +2.4. Subsequent Licenses + + No Contributor makes additional grants as a result of Your choice to + distribute the Covered Software under a subsequent version of this + License (see Section 10.2) or under the terms of a Secondary License (if + permitted under the terms of Section 3.3). + +2.5. Representation + + Each Contributor represents that the Contributor believes its + Contributions are its original creation(s) or it has sufficient rights to + grant the rights to its Contributions conveyed by this License. + +2.6. Fair Use + + This License is not intended to limit any rights You have under + applicable copyright doctrines of fair use, fair dealing, or other + equivalents. + +2.7. Conditions + + Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in + Section 2.1. + + +3. Responsibilities + +3.1. Distribution of Source Form + + All distribution of Covered Software in Source Code Form, including any + Modifications that You create or to which You contribute, must be under + the terms of this License. You must inform recipients that the Source + Code Form of the Covered Software is governed by the terms of this + License, and how they can obtain a copy of this License. You may not + attempt to alter or restrict the recipients' rights in the Source Code + Form. + +3.2. Distribution of Executable Form + + If You distribute Covered Software in Executable Form then: + + a. such Covered Software must also be made available in Source Code Form, + as described in Section 3.1, and You must inform recipients of the + Executable Form how they can obtain a copy of such Source Code Form by + reasonable means in a timely manner, at a charge no more than the cost + of distribution to the recipient; and + + b. You may distribute such Executable Form under the terms of this + License, or sublicense it under different terms, provided that the + license for the Executable Form does not attempt to limit or alter the + recipients' rights in the Source Code Form under this License. + +3.3. Distribution of a Larger Work + + You may create and distribute a Larger Work under terms of Your choice, + provided that You also comply with the requirements of this License for + the Covered Software. If the Larger Work is a combination of Covered + Software with a work governed by one or more Secondary Licenses, and the + Covered Software is not Incompatible With Secondary Licenses, this + License permits You to additionally distribute such Covered Software + under the terms of such Secondary License(s), so that the recipient of + the Larger Work may, at their option, further distribute the Covered + Software under the terms of either this License or such Secondary + License(s). + +3.4. Notices + + You may not remove or alter the substance of any license notices + (including copyright notices, patent notices, disclaimers of warranty, or + limitations of liability) contained within the Source Code Form of the + Covered Software, except that You may alter any license notices to the + extent required to remedy known factual inaccuracies. + +3.5. Application of Additional Terms + + You may choose to offer, and to charge a fee for, warranty, support, + indemnity or liability obligations to one or more recipients of Covered + Software. However, You may do so only on Your own behalf, and not on + behalf of any Contributor. You must make it absolutely clear that any + such warranty, support, indemnity, or liability obligation is offered by + You alone, and You hereby agree to indemnify every Contributor for any + liability incurred by such Contributor as a result of warranty, support, + indemnity or liability terms You offer. You may include additional + disclaimers of warranty and limitations of liability specific to any + jurisdiction. + +4. Inability to Comply Due to Statute or Regulation + + If it is impossible for You to comply with any of the terms of this License + with respect to some or all of the Covered Software due to statute, + judicial order, or regulation then You must: (a) comply with the terms of + this License to the maximum extent possible; and (b) describe the + limitations and the code they affect. Such description must be placed in a + text file included with all distributions of the Covered Software under + this License. Except to the extent prohibited by statute or regulation, + such description must be sufficiently detailed for a recipient of ordinary + skill to be able to understand it. + +5. Termination + +5.1. The rights granted under this License will terminate automatically if You + fail to comply with any of its terms. However, if You become compliant, + then the rights granted under this License from a particular Contributor + are reinstated (a) provisionally, unless and until such Contributor + explicitly and finally terminates Your grants, and (b) on an ongoing + basis, if such Contributor fails to notify You of the non-compliance by + some reasonable means prior to 60 days after You have come back into + compliance. Moreover, Your grants from a particular Contributor are + reinstated on an ongoing basis if such Contributor notifies You of the + non-compliance by some reasonable means, this is the first time You have + received notice of non-compliance with this License from such + Contributor, and You become compliant prior to 30 days after Your receipt + of the notice. + +5.2. If You initiate litigation against any entity by asserting a patent + infringement claim (excluding declaratory judgment actions, + counter-claims, and cross-claims) alleging that a Contributor Version + directly or indirectly infringes any patent, then the rights granted to + You by any and all Contributors for the Covered Software under Section + 2.1 of this License shall terminate. + +5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user + license agreements (excluding distributors and resellers) which have been + validly granted by You or Your distributors under this License prior to + termination shall survive termination. + +6. Disclaimer of Warranty + + Covered Software is provided under this License on an "as is" basis, + without warranty of any kind, either expressed, implied, or statutory, + including, without limitation, warranties that the Covered Software is free + of defects, merchantable, fit for a particular purpose or non-infringing. + The entire risk as to the quality and performance of the Covered Software + is with You. Should any Covered Software prove defective in any respect, + You (not any Contributor) assume the cost of any necessary servicing, + repair, or correction. This disclaimer of warranty constitutes an essential + part of this License. No use of any Covered Software is authorized under + this License except under this disclaimer. + +7. Limitation of Liability + + Under no circumstances and under no legal theory, whether tort (including + negligence), contract, or otherwise, shall any Contributor, or anyone who + distributes Covered Software as permitted above, be liable to You for any + direct, indirect, special, incidental, or consequential damages of any + character including, without limitation, damages for lost profits, loss of + goodwill, work stoppage, computer failure or malfunction, or any and all + other commercial damages or losses, even if such party shall have been + informed of the possibility of such damages. This limitation of liability + shall not apply to liability for death or personal injury resulting from + such party's negligence to the extent applicable law prohibits such + limitation. Some jurisdictions do not allow the exclusion or limitation of + incidental or consequential damages, so this exclusion and limitation may + not apply to You. + +8. Litigation + + Any litigation relating to this License may be brought only in the courts + of a jurisdiction where the defendant maintains its principal place of + business and such litigation shall be governed by laws of that + jurisdiction, without reference to its conflict-of-law provisions. Nothing + in this Section shall prevent a party's ability to bring cross-claims or + counter-claims. + +9. Miscellaneous + + This License represents the complete agreement concerning the subject + matter hereof. If any provision of this License is held to be + unenforceable, such provision shall be reformed only to the extent + necessary to make it enforceable. Any law or regulation which provides that + the language of a contract shall be construed against the drafter shall not + be used to construe this License against a Contributor. + + +10. Versions of the License + +10.1. New Versions + + Mozilla Foundation is the license steward. Except as provided in Section + 10.3, no one other than the license steward has the right to modify or + publish new versions of this License. Each version will be given a + distinguishing version number. + +10.2. Effect of New Versions + + You may distribute the Covered Software under the terms of the version + of the License under which You originally received the Covered Software, + or under the terms of any subsequent version published by the license + steward. + +10.3. Modified Versions + + If you create software not governed by this License, and you want to + create a new license for such software, you may create and use a + modified version of this License if you rename the license and remove + any references to the name of the license steward (except to note that + such modified license differs from this License). + +10.4. Distributing Source Code Form that is Incompatible With Secondary + Licenses If You choose to distribute Source Code Form that is + Incompatible With Secondary Licenses under the terms of this version of + the License, the notice described in Exhibit B of this License must be + attached. + +Exhibit A - Source Code Form License Notice + + This Source Code Form is subject to the + terms of the Mozilla Public License, v. + 2.0. If a copy of the MPL was not + distributed with this file, You can + obtain one at + http://mozilla.org/MPL/2.0/. + +If it is not possible or desirable to put the notice in a particular file, +then You may include the notice in a location (such as a LICENSE file in a +relevant directory) where a recipient would be likely to look for such a +notice. + +You may add additional accurate notices of copyright ownership. + +Exhibit B - "Incompatible With Secondary Licenses" Notice + + This Source Code Form is "Incompatible + With Secondary Licenses", as defined by + the Mozilla Public License, v. 2.0. diff --git a/vendor/github.com/hashicorp/golang-lru/arc.go b/vendor/github.com/hashicorp/golang-lru/arc.go new file mode 100644 index 00000000..a2a25281 --- /dev/null +++ b/vendor/github.com/hashicorp/golang-lru/arc.go @@ -0,0 +1,257 @@ +package lru + +import ( + "sync" + + "github.com/hashicorp/golang-lru/simplelru" +) + +// ARCCache is a thread-safe fixed size Adaptive Replacement Cache (ARC). +// ARC is an enhancement over the standard LRU cache in that tracks both +// frequency and recency of use. This avoids a burst in access to new +// entries from evicting the frequently used older entries. It adds some +// additional tracking overhead to a standard LRU cache, computationally +// it is roughly 2x the cost, and the extra memory overhead is linear +// with the size of the cache. ARC has been patented by IBM, but is +// similar to the TwoQueueCache (2Q) which requires setting parameters. +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 + + t2 *simplelru.LRU // T2 is the LRU for frequently accessed items + b2 *simplelru.LRU // B2 is the LRU for evictions from t2 + + lock sync.RWMutex +} + +// NewARC creates an ARC of the given size +func NewARC(size int) (*ARCCache, error) { + // Create the sub LRUs + b1, err := simplelru.NewLRU(size, nil) + if err != nil { + return nil, err + } + b2, err := simplelru.NewLRU(size, nil) + if err != nil { + return nil, err + } + t1, err := simplelru.NewLRU(size, nil) + if err != nil { + return nil, err + } + t2, err := simplelru.NewLRU(size, nil) + if err != nil { + return nil, err + } + + // Initialize the ARC + c := &ARCCache{ + size: size, + p: 0, + t1: t1, + b1: b1, + t2: t2, + b2: b2, + } + return c, nil +} + +// Get looks up a key's value from the cache. +func (c *ARCCache) Get(key interface{}) (interface{}, bool) { + c.lock.Lock() + defer c.lock.Unlock() + + // Ff 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) + c.t2.Add(key, val) + return val, ok + } + + // Check if the value is contained in T2 (frequent) + if val, ok := c.t2.Get(key); ok { + return val, ok + } + + // No hit + return nil, false +} + +// Add adds a value to the cache. +func (c *ARCCache) Add(key, value interface{}) { + c.lock.Lock() + defer c.lock.Unlock() + + // Check if the value is contained in T1 (recent), and potentially + // promote it to frequent T2 + if c.t1.Contains(key) { + c.t1.Remove(key) + c.t2.Add(key, value) + return + } + + // Check if the value is already in T2 (frequent) and update it + if c.t2.Contains(key) { + c.t2.Add(key, value) + return + } + + // Check if this value was recently evicted as part of the + // recently used list + if c.b1.Contains(key) { + // T1 set is too small, increase P appropriately + delta := 1 + b1Len := c.b1.Len() + b2Len := c.b2.Len() + if b2Len > b1Len { + delta = b2Len / b1Len + } + if c.p+delta >= c.size { + c.p = c.size + } else { + c.p += delta + } + + // Potentially need to make room in the cache + if c.t1.Len()+c.t2.Len() >= c.size { + c.replace(false) + } + + // Remove from B1 + c.b1.Remove(key) + + // Add the key to the frequently used list + c.t2.Add(key, value) + return + } + + // Check if this value was recently evicted as part of the + // frequently used list + if c.b2.Contains(key) { + // T2 set is too small, decrease P appropriately + delta := 1 + b1Len := c.b1.Len() + b2Len := c.b2.Len() + if b1Len > b2Len { + delta = b1Len / b2Len + } + if delta >= c.p { + c.p = 0 + } else { + c.p -= delta + } + + // Potentially need to make room in the cache + if c.t1.Len()+c.t2.Len() >= c.size { + c.replace(true) + } + + // Remove from B2 + c.b2.Remove(key) + + // Add the key to the frequntly used list + c.t2.Add(key, value) + return + } + + // Potentially need to make room in the cache + if c.t1.Len()+c.t2.Len() >= c.size { + c.replace(false) + } + + // Keep the size of the ghost buffers trim + if c.b1.Len() > c.size-c.p { + c.b1.RemoveOldest() + } + if c.b2.Len() > c.p { + c.b2.RemoveOldest() + } + + // Add to the recently seen list + c.t1.Add(key, value) + return +} + +// replace is used to adaptively evict from either T1 or T2 +// based on the current learned value of P +func (c *ARCCache) replace(b2ContainsKey bool) { + t1Len := c.t1.Len() + if t1Len > 0 && (t1Len > c.p || (t1Len == c.p && b2ContainsKey)) { + k, _, ok := c.t1.RemoveOldest() + if ok { + c.b1.Add(k, nil) + } + } else { + k, _, ok := c.t2.RemoveOldest() + if ok { + c.b2.Add(k, nil) + } + } +} + +// Len returns the number of cached entries +func (c *ARCCache) Len() int { + c.lock.RLock() + defer c.lock.RUnlock() + return c.t1.Len() + c.t2.Len() +} + +// Keys returns all the cached keys +func (c *ARCCache) Keys() []interface{} { + c.lock.RLock() + defer c.lock.RUnlock() + k1 := c.t1.Keys() + k2 := c.t2.Keys() + return append(k1, k2...) +} + +// Remove is used to purge a key from the cache +func (c *ARCCache) Remove(key interface{}) { + c.lock.Lock() + defer c.lock.Unlock() + if c.t1.Remove(key) { + return + } + if c.t2.Remove(key) { + return + } + if c.b1.Remove(key) { + return + } + if c.b2.Remove(key) { + return + } +} + +// Purge is used to clear the cache +func (c *ARCCache) Purge() { + c.lock.Lock() + defer c.lock.Unlock() + c.t1.Purge() + c.t2.Purge() + c.b1.Purge() + c.b2.Purge() +} + +// Contains is used to check if the cache contains a key +// without updating recency or frequency. +func (c *ARCCache) Contains(key interface{}) bool { + c.lock.RLock() + defer c.lock.RUnlock() + return c.t1.Contains(key) || c.t2.Contains(key) +} + +// Peek is used to inspect the cache value of a key +// without updating recency or frequency. +func (c *ARCCache) Peek(key interface{}) (interface{}, bool) { + c.lock.RLock() + defer c.lock.RUnlock() + if val, ok := c.t1.Peek(key); ok { + return val, ok + } + return c.t2.Peek(key) +} diff --git a/vendor/github.com/hashicorp/golang-lru/lru.go b/vendor/github.com/hashicorp/golang-lru/lru.go new file mode 100644 index 00000000..a6285f98 --- /dev/null +++ b/vendor/github.com/hashicorp/golang-lru/lru.go @@ -0,0 +1,114 @@ +// 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 ( + "sync" + + "github.com/hashicorp/golang-lru/simplelru" +) + +// Cache is a thread-safe fixed size LRU cache. +type Cache struct { + lru *simplelru.LRU + lock sync.RWMutex +} + +// New creates an LRU of the given size +func New(size int) (*Cache, error) { + return NewWithEvict(size, nil) +} + +// NewWithEvict constructs a fixed size cache with the given eviction +// callback. +func NewWithEvict(size int, onEvicted func(key interface{}, value interface{})) (*Cache, error) { + lru, err := simplelru.NewLRU(size, simplelru.EvictCallback(onEvicted)) + if err != nil { + return nil, err + } + c := &Cache{ + lru: lru, + } + return c, nil +} + +// Purge is used to completely clear the cache +func (c *Cache) Purge() { + c.lock.Lock() + c.lru.Purge() + c.lock.Unlock() +} + +// Add adds a value to the cache. Returns true if an eviction occurred. +func (c *Cache) Add(key, value interface{}) 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) { + 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. +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 +// the "recently used"-ness of the key. +func (c *Cache) Peek(key interface{}) (interface{}, bool) { + c.lock.RLock() + defer c.lock.RUnlock() + return c.lru.Peek(key) +} + +// 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) { + 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 + } +} + +// Remove removes the provided key from the cache. +func (c *Cache) Remove(key interface{}) { + c.lock.Lock() + c.lru.Remove(key) + c.lock.Unlock() +} + +// RemoveOldest removes the oldest item from the cache. +func (c *Cache) RemoveOldest() { + c.lock.Lock() + c.lru.RemoveOldest() + c.lock.Unlock() +} + +// Keys returns a slice of the keys in the cache, from oldest to newest. +func (c *Cache) Keys() []interface{} { + c.lock.RLock() + defer c.lock.RUnlock() + return c.lru.Keys() +} + +// Len returns the number of items in the cache. +func (c *Cache) Len() int { + c.lock.RLock() + defer c.lock.RUnlock() + return c.lru.Len() +} 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 00000000..cb416b39 --- /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) + } +} |