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LICENSE
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@ -1,21 +0,0 @@
MIT License
Copyright (c) 2022 Basit Ali
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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# go-cache
Simple thread safe key/value cache for Go.
## Usage
You can initialize the cache using:
```go
cache = gocache.NewCache()
```
And perform the operations using:
```go
// GET a value using key, which returns (value, error)
cache.Get(key)
// SET a value using key
cache.Set(key, value)
// REMOVE a key/value pair using key
cache.Remove(key)
// And FLUSH, which removes all items from the cache
cache.Flush()
```
## Cache Expiration
You can also add an **expiration** to the cache, expired cache will be auto deleted by the `sweeper`.
To initialize a cache using `sweeper` we can use:
```go
cache := NewCacheWithSweeper(10 * time.Minute, 10 * time.Minute, decisionFunc, onEviction)
```
Here, first two parameters are `interval` and `expireAfter`, sweeper will run in the background after specified `interval` to check for expired cache to delete.
The `decisionFunc` and `onEviction` are **optional** functions with the following signature:
```go
decisionFunc func(v interface{}) bool
onEviction func(k string, v interface{})
```
We can use `decisionFunc` as a callback, it will be called by the cache before deleting a key/value, it takes in the value to delete and returns `true` to delete and `false` for not deleting a key/value pair even after expired.
The `onEviction` is a callback which will be called every time a cache is deleted with its key/value as parameters.

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@ -4,5 +4,4 @@ type Cache interface {
Get(key string) (interface{}, error) Get(key string) (interface{}, error)
Set(key string, data interface{}) error Set(key string, data interface{}) error
Remove(key string) error Remove(key string) error
Flush()
} }

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@ -1,21 +0,0 @@
package gocache
import "time"
func (cache *myCache) deleteExpired() {
cache.mutex.Lock()
defer cache.mutex.Unlock()
now := time.Now().UnixNano()
for k, v := range cache.items {
if cache.decisionFunc != nil && !cache.decisionFunc(v.data) {
continue
}
if v.expiration > 0 && now > v.expiration {
if cache.onEviction != nil {
cache.onEviction(k, v.data)
}
delete(cache.items, k)
}
}
}

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@ -3,5 +3,5 @@ package gocache
import "errors" import "errors"
var ( var (
ErrKeyNotFound = errors.New("key not found") ErrKeyNotFound = errors.New("Key not found")
) )

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@ -1,8 +0,0 @@
package gocache
func (cache *myCache) Flush() {
cache.mutex.Lock()
defer cache.mutex.Unlock()
cache.items = make(map[string]*value)
}

2
get.go
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@ -9,5 +9,5 @@ func (cache *myCache) Get(key string) (interface{}, error) {
return nil, ErrKeyNotFound return nil, ErrKeyNotFound
} }
return item.data, nil return item, nil
} }

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@ -2,15 +2,11 @@ package gocache
import ( import (
"sync" "sync"
"time"
) )
type myCache struct { type myCache struct {
mutex sync.Mutex mutex sync.Mutex
items map[string]*value items map[string]*value
expireAfter int64
decisionFunc func(v interface{}) bool
onEviction func(k string, v interface{})
} }
func NewCache() Cache { func NewCache() Cache {
@ -18,21 +14,3 @@ func NewCache() Cache {
items: make(map[string]*value), items: make(map[string]*value),
} }
} }
func NewCacheWithSweeper(interval, expireAfter time.Duration,
decisionFunc func(v interface{}) bool, onEviction func(k string, v interface{})) Cache {
c := &myCache{
items: make(map[string]*value),
expireAfter: expireAfter.Nanoseconds(),
decisionFunc: decisionFunc,
onEviction: onEviction,
}
if interval > 0 && expireAfter > 0 {
s := newSweeper(c, interval)
// runtime.SetFinalizer(c, s.stopSweeper)
go s.run(c)
}
return c
}

4
set.go
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@ -1,12 +1,10 @@
package gocache package gocache
import "time"
func (cache *myCache) Set(key string, data interface{}) error { func (cache *myCache) Set(key string, data interface{}) error {
cache.mutex.Lock() cache.mutex.Lock()
defer cache.mutex.Unlock() defer cache.mutex.Unlock()
value := newValue(key, data, time.Now().UnixNano()+cache.expireAfter) value := newValue(key, data)
cache.items[key] = value cache.items[key] = value
return nil return nil

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@ -1,32 +0,0 @@
package gocache
import "time"
type sweeper struct {
Interval time.Duration
stop chan bool
}
func (s *sweeper) run(c *myCache) {
ticker := time.NewTicker(s.Interval)
for {
select {
case <-ticker.C:
c.deleteExpired()
case <-s.stop:
ticker.Stop()
return
}
}
}
func newSweeper(c *myCache, i time.Duration) *sweeper {
return &sweeper{
Interval: i,
stop: make(chan bool),
}
}
func (s *sweeper) stopSweeper() {
s.stop <- true
}

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@ -3,13 +3,11 @@ package gocache
type value struct { type value struct {
key string key string
data interface{} data interface{}
expiration int64
} }
func newValue(key string, data interface{}, expiration int64) *value { func newValue(key string, data interface{}) *value {
return &value{ return &value{
key: key, key: key,
data: data, data: data,
expiration: expiration,
} }
} }