diff options
Diffstat (limited to 'vendor/github.com/boltdb/bolt/bolt_windows.go')
-rw-r--r-- | vendor/github.com/boltdb/bolt/bolt_windows.go | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/vendor/github.com/boltdb/bolt/bolt_windows.go b/vendor/github.com/boltdb/bolt/bolt_windows.go new file mode 100644 index 000000000..b00fb0720 --- /dev/null +++ b/vendor/github.com/boltdb/bolt/bolt_windows.go @@ -0,0 +1,144 @@ +package bolt + +import ( + "fmt" + "os" + "syscall" + "time" + "unsafe" +) + +// LockFileEx code derived from golang build filemutex_windows.go @ v1.5.1 +var ( + modkernel32 = syscall.NewLazyDLL("kernel32.dll") + procLockFileEx = modkernel32.NewProc("LockFileEx") + procUnlockFileEx = modkernel32.NewProc("UnlockFileEx") +) + +const ( + lockExt = ".lock" + + // see https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx + flagLockExclusive = 2 + flagLockFailImmediately = 1 + + // see https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx + errLockViolation syscall.Errno = 0x21 +) + +func lockFileEx(h syscall.Handle, flags, reserved, locklow, lockhigh uint32, ol *syscall.Overlapped) (err error) { + r, _, err := procLockFileEx.Call(uintptr(h), uintptr(flags), uintptr(reserved), uintptr(locklow), uintptr(lockhigh), uintptr(unsafe.Pointer(ol))) + if r == 0 { + return err + } + return nil +} + +func unlockFileEx(h syscall.Handle, reserved, locklow, lockhigh uint32, ol *syscall.Overlapped) (err error) { + r, _, err := procUnlockFileEx.Call(uintptr(h), uintptr(reserved), uintptr(locklow), uintptr(lockhigh), uintptr(unsafe.Pointer(ol)), 0) + if r == 0 { + return err + } + return nil +} + +// fdatasync flushes written data to a file descriptor. +func fdatasync(db *DB) error { + return db.file.Sync() +} + +// flock acquires an advisory lock on a file descriptor. +func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error { + // Create a separate lock file on windows because a process + // cannot share an exclusive lock on the same file. This is + // needed during Tx.WriteTo(). + f, err := os.OpenFile(db.path+lockExt, os.O_CREATE, mode) + if err != nil { + return err + } + db.lockfile = f + + var t time.Time + for { + // If we're beyond our timeout then return an error. + // This can only occur after we've attempted a flock once. + if t.IsZero() { + t = time.Now() + } else if timeout > 0 && time.Since(t) > timeout { + return ErrTimeout + } + + var flag uint32 = flagLockFailImmediately + if exclusive { + flag |= flagLockExclusive + } + + err := lockFileEx(syscall.Handle(db.lockfile.Fd()), flag, 0, 1, 0, &syscall.Overlapped{}) + if err == nil { + return nil + } else if err != errLockViolation { + return err + } + + // Wait for a bit and try again. + time.Sleep(50 * time.Millisecond) + } +} + +// funlock releases an advisory lock on a file descriptor. +func funlock(db *DB) error { + err := unlockFileEx(syscall.Handle(db.lockfile.Fd()), 0, 1, 0, &syscall.Overlapped{}) + db.lockfile.Close() + os.Remove(db.path + lockExt) + return err +} + +// mmap memory maps a DB's data file. +// Based on: https://github.com/edsrzf/mmap-go +func mmap(db *DB, sz int) error { + if !db.readOnly { + // Truncate the database to the size of the mmap. + if err := db.file.Truncate(int64(sz)); err != nil { + return fmt.Errorf("truncate: %s", err) + } + } + + // Open a file mapping handle. + sizelo := uint32(sz >> 32) + sizehi := uint32(sz) & 0xffffffff + h, errno := syscall.CreateFileMapping(syscall.Handle(db.file.Fd()), nil, syscall.PAGE_READONLY, sizelo, sizehi, nil) + if h == 0 { + return os.NewSyscallError("CreateFileMapping", errno) + } + + // Create the memory map. + addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, uintptr(sz)) + if addr == 0 { + return os.NewSyscallError("MapViewOfFile", errno) + } + + // Close mapping handle. + if err := syscall.CloseHandle(syscall.Handle(h)); err != nil { + return os.NewSyscallError("CloseHandle", err) + } + + // Convert to a byte array. + db.data = ((*[maxMapSize]byte)(unsafe.Pointer(addr))) + db.datasz = sz + + return nil +} + +// munmap unmaps a pointer from a file. +// Based on: https://github.com/edsrzf/mmap-go +func munmap(db *DB) error { + if db.data == nil { + return nil + } + + addr := (uintptr)(unsafe.Pointer(&db.data[0])) + if err := syscall.UnmapViewOfFile(addr); err != nil { + return os.NewSyscallError("UnmapViewOfFile", err) + } + return nil +} |