rss-tools/vendor/go.etcd.io/bbolt/bolt_windows.go (view raw)
| 1 | package bbolt |
| 2 | |
| 3 | import ( |
| 4 | "fmt" |
| 5 | "os" |
| 6 | "syscall" |
| 7 | "time" |
| 8 | "unsafe" |
| 9 | |
| 10 | "golang.org/x/sys/windows" |
| 11 | |
| 12 | "go.etcd.io/bbolt/errors" |
| 13 | "go.etcd.io/bbolt/internal/common" |
| 14 | ) |
| 15 | |
| 16 | // fdatasync flushes written data to a file descriptor. |
| 17 | func fdatasync(db *DB) error { |
| 18 | return db.file.Sync() |
| 19 | } |
| 20 | |
| 21 | // flock acquires an advisory lock on a file descriptor. |
| 22 | func flock(db *DB, exclusive bool, timeout time.Duration) error { |
| 23 | var t time.Time |
| 24 | if timeout != 0 { |
| 25 | t = time.Now() |
| 26 | } |
| 27 | var flags uint32 = windows.LOCKFILE_FAIL_IMMEDIATELY |
| 28 | if exclusive { |
| 29 | flags |= windows.LOCKFILE_EXCLUSIVE_LOCK |
| 30 | } |
| 31 | for { |
| 32 | // Fix for https://github.com/etcd-io/bbolt/issues/121. Use byte-range |
| 33 | // -1..0 as the lock on the database file. |
| 34 | var m1 uint32 = (1 << 32) - 1 // -1 in a uint32 |
| 35 | err := windows.LockFileEx(windows.Handle(db.file.Fd()), flags, 0, 1, 0, &windows.Overlapped{ |
| 36 | Offset: m1, |
| 37 | OffsetHigh: m1, |
| 38 | }) |
| 39 | |
| 40 | if err == nil { |
| 41 | return nil |
| 42 | } else if err != windows.ERROR_LOCK_VIOLATION { |
| 43 | return err |
| 44 | } |
| 45 | |
| 46 | // If we timed oumercit then return an error. |
| 47 | if timeout != 0 && time.Since(t) > timeout-flockRetryTimeout { |
| 48 | return errors.ErrTimeout |
| 49 | } |
| 50 | |
| 51 | // Wait for a bit and try again. |
| 52 | time.Sleep(flockRetryTimeout) |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | // funlock releases an advisory lock on a file descriptor. |
| 57 | func funlock(db *DB) error { |
| 58 | var m1 uint32 = (1 << 32) - 1 // -1 in a uint32 |
| 59 | return windows.UnlockFileEx(windows.Handle(db.file.Fd()), 0, 1, 0, &windows.Overlapped{ |
| 60 | Offset: m1, |
| 61 | OffsetHigh: m1, |
| 62 | }) |
| 63 | } |
| 64 | |
| 65 | // mmap memory maps a DB's data file. |
| 66 | // Based on: https://github.com/edsrzf/mmap-go |
| 67 | func mmap(db *DB, sz int) error { |
| 68 | var sizelo, sizehi uint32 |
| 69 | |
| 70 | if !db.readOnly { |
| 71 | // Truncate the database to the size of the mmap. |
| 72 | if err := db.file.Truncate(int64(sz)); err != nil { |
| 73 | return fmt.Errorf("truncate: %s", err) |
| 74 | } |
| 75 | sizehi = uint32(sz >> 32) |
| 76 | sizelo = uint32(sz) |
| 77 | } |
| 78 | |
| 79 | // Open a file mapping handle. |
| 80 | h, errno := syscall.CreateFileMapping(syscall.Handle(db.file.Fd()), nil, syscall.PAGE_READONLY, sizehi, sizelo, nil) |
| 81 | if h == 0 { |
| 82 | return os.NewSyscallError("CreateFileMapping", errno) |
| 83 | } |
| 84 | |
| 85 | // Create the memory map. |
| 86 | addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, 0) |
| 87 | if addr == 0 { |
| 88 | // Do our best and report error returned from MapViewOfFile. |
| 89 | _ = syscall.CloseHandle(h) |
| 90 | return os.NewSyscallError("MapViewOfFile", errno) |
| 91 | } |
| 92 | |
| 93 | // Close mapping handle. |
| 94 | if err := syscall.CloseHandle(syscall.Handle(h)); err != nil { |
| 95 | return os.NewSyscallError("CloseHandle", err) |
| 96 | } |
| 97 | |
| 98 | // Convert to a byte array. |
| 99 | db.data = (*[common.MaxMapSize]byte)(unsafe.Pointer(addr)) |
| 100 | db.datasz = sz |
| 101 | |
| 102 | return nil |
| 103 | } |
| 104 | |
| 105 | // munmap unmaps a pointer from a file. |
| 106 | // Based on: https://github.com/edsrzf/mmap-go |
| 107 | func munmap(db *DB) error { |
| 108 | if db.data == nil { |
| 109 | return nil |
| 110 | } |
| 111 | |
| 112 | addr := (uintptr)(unsafe.Pointer(&db.data[0])) |
| 113 | var err1 error |
| 114 | if err := syscall.UnmapViewOfFile(addr); err != nil { |
| 115 | err1 = os.NewSyscallError("UnmapViewOfFile", err) |
| 116 | } |
| 117 | db.data = nil |
| 118 | db.datasz = 0 |
| 119 | return err1 |
| 120 | } |