Adding upstream version 1.0.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

cache.go

@@ -0,0 +1,118 @@
+// Copyright 2013 Beego Authors
+// Copyright 2014 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+// Package cache is a middleware that aim to have a transparent interface for a lot of cache implementations
+package cache
+
+import (
+	"fmt"
+)
+
+// Cache is the interface that operates the cache data.
+type Cache interface {
+	// Put puts value into cache with key and expire time.
+	Put(key string, val any, timeout int64) error
+	// Get gets cached value by given key.
+	Get(key string) any
+	// Delete deletes cached value by given key.
+	Delete(key string) error
+	// Incr increases cached int-type value by given key as a counter.
+	Incr(key string) error
+	// Decr decreases cached int-type value by given key as a counter.
+	Decr(key string) error
+	// IsExist returns true if cached value exists.
+	IsExist(key string) bool
+	// Flush deletes all cached data.
+	Flush() error
+	// StartAndGC starts GC routine based on config string settings.
+	StartAndGC(opt Options) error
+	// Ping tests if the cache is alive
+	Ping() error
+}
+
+// Options represents a struct for specifying configuration options for the cache middleware.
+type Options struct {
+	// Name of adapter. Default is "memory".
+	Adapter string
+	// Adapter configuration, it's corresponding to adapter.
+	AdapterConfig string
+	// GC interval time in seconds. Default is 60.
+	Interval int
+	// Occupy entire database. Default is false.
+	OccupyMode bool
+	// Configuration section name. Default is "cache".
+	Section string
+}
+
+func prepareOptions(opt Options) Options {
+	if len(opt.Section) == 0 {
+		opt.Section = "cache"
+	}
+	if len(opt.Adapter) == 0 {
+		opt.Adapter = "memory"
+	}
+	if opt.Interval == 0 {
+		opt.Interval = 60
+	}
+	if len(opt.AdapterConfig) == 0 {
+		opt.AdapterConfig = "data/caches"
+	}
+
+	return opt
+}
+
+// NewCacher creates and returns a new cacher by given adapter name and configuration.
+// It panics when given adapter isn't registered and starts GC automatically.
+func NewCacher(opt Options) (Cache, error) {
+	opt = prepareOptions(opt)
+	adapter, ok := adapters[opt.Adapter]
+	if !ok {
+		return nil, fmt.Errorf("cache: unknown adapter '%s'(forgot to import?)", opt.Adapter)
+	}
+	return adapter, adapter.StartAndGC(opt)
+}
+
+var adapters = make(map[string]Cache)
+
+// Register registers a adapter.
+func Register(name string, adapter Cache) {
+	if adapter == nil {
+		panic("cache: cannot register adapter with nil value")
+	}
+	if _, dup := adapters[name]; dup {
+		panic(fmt.Errorf("cache: cannot register adapter '%s' twice", name))
+	}
+	adapters[name] = adapter
+}
+
+const (
+	pingTestKey = "__chi_cache_test"
+	pingTestVal = "test-value"
+)
+
+// GenericPing test a cache by storing and retrieving a value
+func GenericPing(c Cache) error {
+	if err := c.Put(pingTestKey, pingTestVal, 10); err != nil {
+		return err
+	}
+	val := c.Get(pingTestKey)
+	if valStr, ok := val.(string); !ok || valStr != pingTestVal {
+		return fmt.Errorf("ping doesn't seem to work correctly, set test value '%v' but get '%v'",
+			pingTestVal,
+			val,
+		)
+	}
+	return c.Delete(pingTestKey)
+}