mirror of
https://github.com/ncruces/go-sqlite3.git
synced 2026-01-11 21:49:13 +00:00
116 lines
2.7 KiB
Go
116 lines
2.7 KiB
Go
package sqlite3
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import (
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"os"
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"syscall"
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"golang.org/x/sys/windows"
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)
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func deleteOnClose(f *os.File) {}
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func (l *vfsFileLocker) GetShared() xErrorCode {
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// Acquire the SHARED lock.
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return l.readLock(_SHARED_FIRST, _SHARED_SIZE)
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}
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func (l *vfsFileLocker) GetReserved() xErrorCode {
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// Acquire the RESERVED lock.
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return l.writeLock(_RESERVED_BYTE, 1)
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}
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func (l *vfsFileLocker) GetPending() xErrorCode {
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// Acquire the PENDING lock.
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return l.writeLock(_PENDING_BYTE, 1)
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}
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func (l *vfsFileLocker) GetExclusive() xErrorCode {
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// Release the SHARED lock.
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l.unlock(_SHARED_FIRST, _SHARED_SIZE)
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// Acquire the EXCLUSIVE lock.
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rc := l.writeLock(_SHARED_FIRST, _SHARED_SIZE)
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// Reacquire the SHARED lock.
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if rc != _OK {
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l.readLock(_SHARED_FIRST, _SHARED_SIZE)
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}
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return rc
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}
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func (l *vfsFileLocker) Downgrade() xErrorCode {
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// Release the SHARED lock.
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l.unlock(_SHARED_FIRST, _SHARED_SIZE)
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// Reacquire the SHARED lock.
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if rc := l.readLock(_SHARED_FIRST, _SHARED_SIZE); rc != _OK {
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// This should never happen.
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// We should always be able to reacquire the read lock.
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return IOERR_RDLOCK
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}
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// Release the PENDING and RESERVED locks.
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l.unlock(_RESERVED_BYTE, 1)
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l.unlock(_PENDING_BYTE, 1)
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return _OK
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}
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func (l *vfsFileLocker) Release() xErrorCode {
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// Release all locks.
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l.unlock(_SHARED_FIRST, _SHARED_SIZE)
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l.unlock(_RESERVED_BYTE, 1)
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l.unlock(_PENDING_BYTE, 1)
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return _OK
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}
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func (l *vfsFileLocker) CheckReserved() (bool, xErrorCode) {
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// Test the RESERVED lock.
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rc := l.readLock(_RESERVED_BYTE, 1)
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if rc == _OK {
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l.unlock(_RESERVED_BYTE, 1)
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}
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return rc != _OK, _OK
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}
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func (l *vfsFileLocker) CheckPending() (bool, xErrorCode) {
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// Test the PENDING lock.
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rc := l.readLock(_PENDING_BYTE, 1)
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if rc == _OK {
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l.unlock(_PENDING_BYTE, 1)
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}
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return rc != _OK, _OK
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}
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func (l *vfsFileLocker) unlock(start, len uint32) xErrorCode {
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err := windows.UnlockFileEx(windows.Handle(l.file.Fd()),
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0, len, 0, &windows.Overlapped{Offset: start})
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if err != nil {
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return IOERR_UNLOCK
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}
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return _OK
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}
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func (l *vfsFileLocker) readLock(start, len uint32) xErrorCode {
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return l.errorCode(windows.LockFileEx(windows.Handle(l.file.Fd()),
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windows.LOCKFILE_FAIL_IMMEDIATELY,
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0, len, 0, &windows.Overlapped{Offset: start}),
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IOERR_RDLOCK)
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}
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func (l *vfsFileLocker) writeLock(start, len uint32) xErrorCode {
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return l.errorCode(windows.LockFileEx(windows.Handle(l.file.Fd()),
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windows.LOCKFILE_FAIL_IMMEDIATELY|windows.LOCKFILE_EXCLUSIVE_LOCK,
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0, len, 0, &windows.Overlapped{Offset: start}),
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IOERR_LOCK)
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}
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func (*vfsFileLocker) errorCode(err error, def xErrorCode) xErrorCode {
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if err == nil {
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return _OK
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}
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if errno, _ := err.(syscall.Errno); errno == windows.ERROR_INVALID_HANDLE {
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return def
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}
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return xErrorCode(BUSY)
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}
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