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// Copyright (c) 2017 Uber Technologies, Inc.
//
// 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 rpcmetrics
import "sync"
// normalizedEndpoints is a cache for endpointName -> safeName mappings.
type normalizedEndpoints struct {
names map[string]string
maxSize int
defaultName string
normalizer NameNormalizer
mux sync.RWMutex
}
func newNormalizedEndpoints(maxSize int, normalizer NameNormalizer) *normalizedEndpoints {
return &normalizedEndpoints{
maxSize: maxSize,
normalizer: normalizer,
names: make(map[string]string, maxSize),
}
}
// normalize looks up the name in the cache, if not found it uses normalizer
// to convert the name to a safe name. If called with more than maxSize unique
// names it returns "" for all other names beyond those already cached.
func (n *normalizedEndpoints) normalize(name string) string {
n.mux.RLock()
norm, ok := n.names[name]
l := len(n.names)
n.mux.RUnlock()
if ok {
return norm
}
if l >= n.maxSize {
return ""
}
return n.normalizeWithLock(name)
}
func (n *normalizedEndpoints) normalizeWithLock(name string) string {
norm := n.normalizer.Normalize(name)
n.mux.Lock()
defer n.mux.Unlock()
// cache may have grown while we were not holding the lock
if len(n.names) >= n.maxSize {
return ""
}
n.names[name] = norm
return norm
}
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