forked from cerc-io/plugeth
47 lines
1.6 KiB
Go
47 lines
1.6 KiB
Go
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// Copyright 2016 The Prometheus 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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//
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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 flock provides portable file locking. It is essentially ripped out
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// from the code of github.com/syndtr/goleveldb. Strange enough that the
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// standard library does not provide this functionality. Once this package has
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// proven to work as expected, we should probably turn it into a separate
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// general purpose package for humanity.
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package flock
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import (
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"os"
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"path/filepath"
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)
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// Releaser provides the Release method to release a file lock.
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type Releaser interface {
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Release() error
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}
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// New locks the file with the provided name. If the file does not exist, it is
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// created. The returned Releaser is used to release the lock. existed is true
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// if the file to lock already existed. A non-nil error is returned if the
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// locking has failed. Neither this function nor the returned Releaser is
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// goroutine-safe.
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func New(fileName string) (r Releaser, existed bool, err error) {
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if err = os.MkdirAll(filepath.Dir(fileName), 0755); err != nil {
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return
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}
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_, err = os.Stat(fileName)
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existed = err == nil
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r, err = newLock(fileName)
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return
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}
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