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111 lines
2.4 KiB
111 lines
2.4 KiB
9 years ago
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/*
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* Minio Cloud Storage, (C) 2015 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Package metadata implements in memory caching methods for metadata information
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package metadata
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import (
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"sync"
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"time"
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)
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var noExpiration = time.Duration(0)
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// Cache holds the required variables to compose an in memory cache system
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// which also provides expiring key mechanism and also maxSize
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type Cache struct {
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// Mutex is used for handling the concurrent
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// read/write requests for cache
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sync.Mutex
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// items hold the cached objects
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items map[string]interface{}
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// updatedAt holds the time that related item's updated at
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updatedAt map[string]time.Time
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}
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// Stats current cache statistics
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type Stats struct {
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Items int
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}
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// NewCache creates an inmemory cache
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//
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func NewCache() *Cache {
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return &Cache{
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items: make(map[string]interface{}),
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updatedAt: map[string]time.Time{},
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}
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}
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// Stats get current cache statistics
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func (r *Cache) Stats() Stats {
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return Stats{
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Items: len(r.items),
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}
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}
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// GetAll returs all the items
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func (r *Cache) GetAll() map[string]interface{} {
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r.Lock()
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defer r.Unlock()
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// copy
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items := r.items
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return items
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}
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// Get returns a value of a given key if it exists
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func (r *Cache) Get(key string) interface{} {
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r.Lock()
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defer r.Unlock()
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value, ok := r.items[key]
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if !ok {
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return nil
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}
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return value
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}
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// Exists returns true if key exists
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func (r *Cache) Exists(key string) bool {
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r.Lock()
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defer r.Unlock()
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_, ok := r.items[key]
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return ok
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}
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// Set will persist a value to the cache
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func (r *Cache) Set(key string, value interface{}) bool {
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r.Lock()
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defer r.Unlock()
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r.items[key] = value
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return true
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}
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// Delete deletes a given key if exists
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func (r *Cache) Delete(key string) {
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r.Lock()
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defer r.Unlock()
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r.doDelete(key)
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}
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func (r *Cache) doDelete(key string) {
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if _, ok := r.items[key]; ok {
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delete(r.items, key)
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delete(r.updatedAt, key)
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}
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}
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