mirror of https://github.com/k3s-io/k3s
103 lines
2.4 KiB
Go
103 lines
2.4 KiB
Go
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/*
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Copyright 2017 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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 registrar
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import (
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"sync"
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"github.com/pkg/errors"
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)
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// Registrar stores one-to-one name<->key mappings.
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// Names and keys must be unique.
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// Registrar is safe for concurrent access.
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type Registrar struct {
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lock sync.Mutex
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nameToKey map[string]string
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keyToName map[string]string
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}
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// NewRegistrar creates a new Registrar with the empty indexes.
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func NewRegistrar() *Registrar {
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return &Registrar{
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nameToKey: make(map[string]string),
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keyToName: make(map[string]string),
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}
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}
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// Reserve registers a name<->key mapping, name or key must not
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// be empty.
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// Reserve is idempotent.
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// Attempting to reserve a conflict key<->name mapping results
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// in an error.
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// A name<->key reservation is globally unique.
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func (r *Registrar) Reserve(name, key string) error {
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r.lock.Lock()
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defer r.lock.Unlock()
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if name == "" || key == "" {
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return errors.Errorf("invalid name %q or key %q", name, key)
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}
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if k, exists := r.nameToKey[name]; exists {
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if k != key {
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return errors.Errorf("name %q is reserved for %q", name, k)
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}
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return nil
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}
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if n, exists := r.keyToName[key]; exists {
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if n != name {
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return errors.Errorf("key %q is reserved for %q", key, n)
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}
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return nil
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}
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r.nameToKey[name] = key
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r.keyToName[key] = name
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return nil
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}
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// ReleaseByName releases the reserved name<->key mapping by name.
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// Once released, the name and the key can be reserved again.
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func (r *Registrar) ReleaseByName(name string) {
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r.lock.Lock()
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defer r.lock.Unlock()
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key, exists := r.nameToKey[name]
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if !exists {
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return
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}
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delete(r.nameToKey, name)
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delete(r.keyToName, key)
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}
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// ReleaseByKey release the reserved name<->key mapping by key.
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func (r *Registrar) ReleaseByKey(key string) {
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r.lock.Lock()
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defer r.lock.Unlock()
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name, exists := r.keyToName[key]
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if !exists {
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return
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}
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delete(r.nameToKey, name)
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delete(r.keyToName, key)
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}
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