32 lines
885 B
Go
32 lines
885 B
Go
//go:build !windows
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package flock
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import (
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"errors"
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"os"
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"syscall"
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)
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// TryLock attempts to acquire an exclusive, non-blocking flock on the given path.
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// Returns the locked file and an unlock function on success. The caller should
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// read/write through the returned file to avoid platform differences with
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// mandatory locking on Windows.
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// Returns ErrLocked if the file is already locked by another process.
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func TryLock(path string) (f *os.File, unlock func(), err error) {
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f, err = os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0o644)
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if err != nil {
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return nil, nil, err
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}
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if err := syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
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_ = f.Close()
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if errors.Is(err, syscall.EWOULDBLOCK) {
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return nil, nil, ErrLocked
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}
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return nil, nil, err
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}
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return f, func() {
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_ = syscall.Flock(int(f.Fd()), syscall.LOCK_UN)
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_ = f.Close()
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}, nil
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}
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