41 lines
1,008 B
Go
41 lines
1,008 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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"golang.org/x/sys/windows"
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)
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// TryLock attempts to acquire an exclusive, non-blocking lock 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 Windows mandatory lock conflicts.
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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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ol := new(windows.Overlapped)
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handle := windows.Handle(f.Fd())
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err = windows.LockFileEx(
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handle,
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windows.LOCKFILE_EXCLUSIVE_LOCK|windows.LOCKFILE_FAIL_IMMEDIATELY,
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0,
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1, 0,
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ol,
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)
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if err != nil {
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_ = f.Close()
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if errors.Is(err, windows.ERROR_LOCK_VIOLATION) {
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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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_ = windows.UnlockFileEx(handle, 0, 1, 0, ol)
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_ = f.Close()
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}, nil
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}
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