Speed up git diff highlight generation (#16180)
Co-authored-by: Mura Li <typeless@users.noreply.github.com> Co-authored-by: 6543 <6543@obermui.de>tokarchuk/v1.17
Mura Li
3 years ago
committed by
GitHub
parent
b3fbd37e99
commit
19dedc3fa5
@ -0,0 +1,23 @@ |
||||
# Compiled Object files, Static and Dynamic libs (Shared Objects) |
||||
*.o |
||||
*.a |
||||
*.so |
||||
|
||||
# Folders |
||||
_obj |
||||
_test |
||||
|
||||
# Architecture specific extensions/prefixes |
||||
*.[568vq] |
||||
[568vq].out |
||||
|
||||
*.cgo1.go |
||||
*.cgo2.c |
||||
_cgo_defun.c |
||||
_cgo_gotypes.go |
||||
_cgo_export.* |
||||
|
||||
_testmain.go |
||||
|
||||
*.exe |
||||
*.test |
||||
@ -0,0 +1,223 @@ |
||||
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.LRUCache |
||||
frequent simplelru.LRUCache |
||||
recentEvict simplelru.LRUCache |
||||
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 |
||||
} |
||||
|
||||
// Get looks up a key's value from the cache.
|
||||
func (c *TwoQueueCache) Get(key interface{}) (value interface{}, ok 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 |
||||
} |
||||
|
||||
// Add adds a value to the cache.
|
||||
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() |
||||
} |
||||
|
||||
// Len returns the number of items in the cache.
|
||||
func (c *TwoQueueCache) Len() int { |
||||
c.lock.RLock() |
||||
defer c.lock.RUnlock() |
||||
return c.recent.Len() + c.frequent.Len() |
||||
} |
||||
|
||||
// Keys returns a slice of the keys in the cache.
|
||||
// The frequently used keys are first in the returned slice.
|
||||
func (c *TwoQueueCache) Keys() []interface{} { |
||||
c.lock.RLock() |
||||
defer c.lock.RUnlock() |
||||
k1 := c.frequent.Keys() |
||||
k2 := c.recent.Keys() |
||||
return append(k1, k2...) |
||||
} |
||||
|
||||
// Remove removes the provided key from the cache.
|
||||
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 |
||||
} |
||||
} |
||||
|
||||
// Purge is used to completely clear the cache.
|
||||
func (c *TwoQueueCache) Purge() { |
||||
c.lock.Lock() |
||||
defer c.lock.Unlock() |
||||
c.recent.Purge() |
||||
c.frequent.Purge() |
||||
c.recentEvict.Purge() |
||||
} |
||||
|
||||
// Contains is used to check if the cache contains a key
|
||||
// without updating recency or frequency.
|
||||
func (c *TwoQueueCache) Contains(key interface{}) bool { |
||||
c.lock.RLock() |
||||
defer c.lock.RUnlock() |
||||
return c.frequent.Contains(key) || c.recent.Contains(key) |
||||
} |
||||
|
||||
// Peek is used to inspect the cache value of a key
|
||||
// without updating recency or frequency.
|
||||
func (c *TwoQueueCache) Peek(key interface{}) (value interface{}, ok bool) { |
||||
c.lock.RLock() |
||||
defer c.lock.RUnlock() |
||||
if val, ok := c.frequent.Peek(key); ok { |
||||
return val, ok |
||||
} |
||||
return c.recent.Peek(key) |
||||
} |
||||
@ -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. |
||||
@ -0,0 +1,25 @@ |
||||
golang-lru |
||||
========== |
||||
|
||||
This provides the `lru` package which implements a fixed-size |
||||
thread safe LRU cache. It is based on the cache in Groupcache. |
||||
|
||||
Documentation |
||||
============= |
||||
|
||||
Full docs are available on [Godoc](http://godoc.org/github.com/hashicorp/golang-lru) |
||||
|
||||
Example |
||||
======= |
||||
|
||||
Using the LRU is very simple: |
||||
|
||||
```go |
||||
l, _ := New(128) |
||||
for i := 0; i < 256; i++ { |
||||
l.Add(i, nil) |
||||
} |
||||
if l.Len() != 128 { |
||||
panic(fmt.Sprintf("bad len: %v", l.Len())) |
||||
} |
||||
``` |
||||
@ -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.LRUCache // T1 is the LRU for recently accessed items
|
||||
b1 simplelru.LRUCache // B1 is the LRU for evictions from t1
|
||||
|
||||
t2 simplelru.LRUCache // T2 is the LRU for frequently accessed items
|
||||
b2 simplelru.LRUCache // 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{}) (value interface{}, ok bool) { |
||||
c.lock.Lock() |
||||
defer c.lock.Unlock() |
||||
|
||||
// If 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 frequently 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{}) (value interface{}, ok bool) { |
||||
c.lock.RLock() |
||||
defer c.lock.RUnlock() |
||||
if val, ok := c.t1.Peek(key); ok { |
||||
return val, ok |
||||
} |
||||
return c.t2.Peek(key) |
||||
} |
||||
@ -0,0 +1,21 @@ |
||||
// Package lru provides three different LRU caches of varying sophistication.
|
||||
//
|
||||
// Cache is a simple LRU cache. It is based on the
|
||||
// LRU implementation in groupcache:
|
||||
// https://github.com/golang/groupcache/tree/master/lru
|
||||
//
|
||||
// TwoQueueCache tracks frequently used and recently used entries separately.
|
||||
// This avoids a burst of accesses from taking out frequently used entries,
|
||||
// at the cost of about 2x computational overhead and some extra bookkeeping.
|
||||
//
|
||||
// ARCCache is an adaptive replacement cache. It tracks recent evictions as
|
||||
// well as recent usage in both the frequent and recent caches. Its
|
||||
// computational overhead is comparable to TwoQueueCache, but the memory
|
||||
// overhead is linear with the size of the cache.
|
||||
//
|
||||
// ARC has been patented by IBM, so do not use it if that is problematic for
|
||||
// your program.
|
||||
//
|
||||
// All caches in this package take locks while operating, and are therefore
|
||||
// thread-safe for consumers.
|
||||
package lru |
||||
@ -0,0 +1 @@ |
||||
module github.com/hashicorp/golang-lru |
||||
@ -0,0 +1,116 @@ |
||||
package lru |
||||
|
||||
import ( |
||||
"sync" |
||||
|
||||
"github.com/hashicorp/golang-lru/simplelru" |
||||
) |
||||
|
||||
// Cache is a thread-safe fixed size LRU cache.
|
||||
type Cache struct { |
||||
lru simplelru.LRUCache |
||||
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{}) (evicted bool) { |
||||
c.lock.Lock() |
||||
evicted = c.lru.Add(key, value) |
||||
c.lock.Unlock() |
||||
return evicted |
||||
} |
||||
|
||||
// Get looks up a key's value from the cache.
|
||||
func (c *Cache) Get(key interface{}) (value interface{}, ok bool) { |
||||
c.lock.Lock() |
||||
value, ok = c.lru.Get(key) |
||||
c.lock.Unlock() |
||||
return value, ok |
||||
} |
||||
|
||||
// Contains checks 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() |
||||
containKey := c.lru.Contains(key) |
||||
c.lock.RUnlock() |
||||
return containKey |
||||
} |
||||
|
||||
// Peek returns the key value (or undefined if not found) without updating
|
||||
// the "recently used"-ness of the key.
|
||||
func (c *Cache) Peek(key interface{}) (value interface{}, ok bool) { |
||||
c.lock.RLock() |
||||
value, ok = c.lru.Peek(key) |
||||
c.lock.RUnlock() |
||||
return value, ok |
||||
} |
||||
|
||||
// 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, evicted bool) { |
||||
c.lock.Lock() |
||||
defer c.lock.Unlock() |
||||
|
||||
if c.lru.Contains(key) { |
||||
return true, false |
||||
} |
||||
evicted = c.lru.Add(key, value) |
||||
return false, evicted |
||||
} |
||||
|
||||
// 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() |
||||
keys := c.lru.Keys() |
||||
c.lock.RUnlock() |
||||
return keys |
||||
} |
||||
|
||||
// Len returns the number of items in the cache.
|
||||
func (c *Cache) Len() int { |
||||
c.lock.RLock() |
||||
length := c.lru.Len() |
||||
c.lock.RUnlock() |
||||
return length |
||||
} |
||||
@ -0,0 +1,161 @@ |
||||
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{}) (evicted 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 |
||||
} |
||||
|
||||
// Contains checks 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 |
||||
} |
||||
|
||||
// Peek 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) { |
||||
var ent *list.Element |
||||
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{}) (present 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() (key interface{}, value interface{}, ok 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() (key interface{}, value interface{}, ok 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) |
||||
} |
||||
} |
||||
@ -0,0 +1,36 @@ |
||||
package simplelru |
||||
|
||||
// LRUCache is the interface for simple LRU cache.
|
||||
type LRUCache interface { |
||||
// Adds a value to the cache, returns true if an eviction occurred and
|
||||
// updates the "recently used"-ness of the key.
|
||||
Add(key, value interface{}) bool |
||||
|
||||
// Returns key's value from the cache and
|
||||
// updates the "recently used"-ness of the key. #value, isFound
|
||||
Get(key interface{}) (value interface{}, ok bool) |
||||
|
||||
// Check if a key exsists in cache without updating the recent-ness.
|
||||
Contains(key interface{}) (ok bool) |
||||
|
||||
// Returns key's value without updating the "recently used"-ness of the key.
|
||||
Peek(key interface{}) (value interface{}, ok bool) |
||||
|
||||
// Removes a key from the cache.
|
||||
Remove(key interface{}) bool |
||||
|
||||
// Removes the oldest entry from cache.
|
||||
RemoveOldest() (interface{}, interface{}, bool) |
||||
|
||||
// Returns the oldest entry from the cache. #key, value, isFound
|
||||
GetOldest() (interface{}, interface{}, bool) |
||||
|
||||
// Returns a slice of the keys in the cache, from oldest to newest.
|
||||
Keys() []interface{} |
||||
|
||||
// Returns the number of items in the cache.
|
||||
Len() int |
||||
|
||||
// Clear all cache entries
|
||||
Purge() |
||||
} |
||||
Loading…
Reference in new issue