mirror of
https://github.com/caddyserver/caddy.git
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85 lines
2.1 KiB
Go
85 lines
2.1 KiB
Go
// Copyright 2015 Matthew Holt
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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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package certmagic
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import (
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"fmt"
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"sync"
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)
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// MemoryLocker implements the Locker interface
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// using memory. An empty value is NOT VALID,
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// so you must use NewMemoryLocker() to get one.
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type MemoryLocker struct {
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nameLocks map[string]*MemoryWaiter
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nameLocksMu *sync.Mutex
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}
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// NewMemoryLocker returns a valid Locker backed by fs.
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func NewMemoryLocker() *MemoryLocker {
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return &MemoryLocker{
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nameLocks: make(map[string]*MemoryWaiter),
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nameLocksMu: new(sync.Mutex),
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}
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}
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// TryLock attempts to get a lock for name, otherwise it returns
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// a Waiter value to wait until the other process is finished.
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func (l *MemoryLocker) TryLock(name string) (Waiter, error) {
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l.nameLocksMu.Lock()
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defer l.nameLocksMu.Unlock()
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// see if lock already exists within this process
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w, ok := l.nameLocks[name]
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if ok {
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return w, nil
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}
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// we got the lock, so create it
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w = &MemoryWaiter{wg: new(sync.WaitGroup)}
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w.wg.Add(1)
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l.nameLocks[name] = w
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return nil, nil
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}
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// Unlock releases the lock for name.
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func (l *MemoryLocker) Unlock(name string) error {
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l.nameLocksMu.Lock()
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defer l.nameLocksMu.Unlock()
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w, ok := l.nameLocks[name]
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if !ok {
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return fmt.Errorf("MemoryLocker: no lock to release for %s", name)
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}
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w.wg.Done()
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delete(l.nameLocks, name)
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return nil
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}
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// MemoryWaiter implements Waiter in memory.
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type MemoryWaiter struct {
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wg *sync.WaitGroup
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}
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// Wait waits until w.wg is done.
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func (w *MemoryWaiter) Wait() {
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w.Wait()
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}
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var _ Locker = &MemoryLocker{}
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var _ Waiter = &MemoryWaiter{}
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