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// Copyright (c) 2019 Uber Technologies, Inc.
//
// 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.
package tally
import (
"bytes"
"sort"
)
const (
prefixSplitter = '+'
keyPairSplitter = ','
keyNameSplitter = '='
)
var (
keyGenPool = newKeyGenerationPool(1024, 1024, 32)
nilString = ""
)
type keyGenerationPool struct {
bufferPool *ObjectPool
stringsPool *ObjectPool
}
// KeyForStringMap generates a unique key for a map string set combination.
func KeyForStringMap(
stringMap map[string]string,
) string {
return KeyForPrefixedStringMap(nilString, stringMap)
}
// KeyForPrefixedStringMap generates a unique key for a
// a prefix and a map string set combination.
func KeyForPrefixedStringMap(
prefix string,
stringMap map[string]string,
) string {
keys := keyGenPool.stringsPool.Get().([]string)
for k := range stringMap {
keys = append(keys, k)
}
sort.Strings(keys)
buf := keyGenPool.bufferPool.Get().(*bytes.Buffer)
if prefix != nilString {
buf.WriteString(prefix)
buf.WriteByte(prefixSplitter)
}
sortedKeysLen := len(stringMap)
for i := 0; i < sortedKeysLen; i++ {
buf.WriteString(keys[i])
buf.WriteByte(keyNameSplitter)
buf.WriteString(stringMap[keys[i]])
if i != sortedKeysLen-1 {
buf.WriteByte(keyPairSplitter)
}
}
key := buf.String()
keyGenPool.release(buf, keys)
return key
}
func newKeyGenerationPool(size, blen, slen int) *keyGenerationPool {
b := NewObjectPool(size)
b.Init(func() interface{} {
return bytes.NewBuffer(make([]byte, 0, blen))
})
s := NewObjectPool(size)
s.Init(func() interface{} {
return make([]string, 0, slen)
})
return &keyGenerationPool{
bufferPool: b,
stringsPool: s,
}
}
func (s *keyGenerationPool) release(b *bytes.Buffer, strs []string) {
b.Reset()
s.bufferPool.Put(b)
for i := range strs {
strs[i] = nilString
}
s.stringsPool.Put(strs[:0])
}
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