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//go:build (freebsd || openbsd || netbsd || dragonfly || illumos || sqlite3_flock) && !sqlite3_nosys
package vfs
import (
"os"
"golang.org/x/sys/unix"
)
func osGetSharedLock(file *os.File) _ErrorCode {
return osLock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
}
func osGetReservedLock(file *os.File) _ErrorCode {
rc := osLock(file, unix.LOCK_EX|unix.LOCK_NB, _IOERR_LOCK)
if rc == _BUSY {
// The documentation states the lock is upgraded by releasing the previous lock,
// then acquiring the new lock.
// This is a race, so return BUSY_SNAPSHOT to ensure the transaction is aborted.
return _BUSY_SNAPSHOT
}
return rc
}
func osGetExclusiveLock(file *os.File, state *LockLevel) _ErrorCode {
if *state >= LOCK_RESERVED {
return _OK
}
return osGetReservedLock(file)
}
func osDowngradeLock(file *os.File, _ LockLevel) _ErrorCode {
rc := osLock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
if rc == _BUSY {
// The documentation states the lock is upgraded by releasing the previous lock,
// then acquiring the new lock.
// This is a race, so return IOERR_RDLOCK to ensure the transaction is aborted.
return _IOERR_RDLOCK
}
return _OK
}
func osReleaseLock(file *os.File, _ LockLevel) _ErrorCode {
err := unix.Flock(int(file.Fd()), unix.LOCK_UN)
if err != nil {
return _IOERR_UNLOCK
}
return _OK
}
func osCheckReservedLock(file *os.File) (bool, _ErrorCode) {
// Test the RESERVED lock.
lock, rc := osTestLock(file, _RESERVED_BYTE, 1)
return lock == unix.F_WRLCK, rc
}
func osLock(file *os.File, how int, def _ErrorCode) _ErrorCode {
err := unix.Flock(int(file.Fd()), how)
return osLockErrorCode(err, def)
}
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