Exemplo n.º 1
0
Arquivo: xact.go Projeto: devick/flynn
func (f *bitFiler) WriteAt(b []byte, off int64) (n int, err error) {
	off0 := off
	pgI := off >> bfBits
	pgO := int(off & bfMask)
	n = len(b)
	rem := n
	var nc int
	for rem != 0 {
		pg := f.m[pgI]
		if pg == nil {
			pg = &bitPage{}
			if f.parent != nil {
				_, err = f.parent.ReadAt(pg.data[:], off&^bfMask)
				if err != nil && !fileutil.IsEOF(err) {
					return
				}

				err = nil
			}
			f.m[pgI] = pg
		}
		nc = copy(pg.data[pgO:], b)
		pgI++
		pg.dirty = true
		for i := pgO; i < pgO+nc; i++ {
			pg.flags[i>>3] |= bitmask[i&7]
		}
		pgO = 0
		rem -= nc
		b = b[nc:]
		off += int64(nc)
	}
	f.size = mathutil.MaxInt64(f.size, off0+int64(n))
	return
}
Exemplo n.º 2
0
// WriteAt implements Filer.
func (f *MemFiler) WriteAt(b []byte, off int64) (n int, err error) {
	pgI := off >> pgBits
	pgO := int(off & pgMask)
	n = len(b)
	rem := n
	var nc int
	for rem != 0 {
		if pgO == 0 && rem >= pgSize && bytes.Equal(b[:pgSize], zeroPage[:]) {
			delete(f.m, pgI)
			nc = pgSize
		} else {
			pg := f.m[pgI]
			if pg == nil {
				pg = new([pgSize]byte)
				f.m[pgI] = pg
			}
			nc = copy((*pg)[pgO:], b)
		}
		pgI++
		pgO = 0
		rem -= nc
		b = b[nc:]
	}
	f.size = mathutil.MaxInt64(f.size, off+int64(n))
	return
}
Exemplo n.º 3
0
// Size implements Filer.
func (f *InnerFiler) Size() (int64, error) {
	sz, err := f.outer.Size()
	if err != nil {
		return 0, err
	}

	return mathutil.MaxInt64(sz-f.off, 0), nil
}
Exemplo n.º 4
0
// WriteAt implements Filer.
func (f *SimpleFileFiler) WriteAt(b []byte, off int64) (n int, err error) {
	if f.size < 0 { // boot
		fi, err := os.Stat(f.file.Name())
		if err != nil {
			return 0, err
		}

		f.size = fi.Size()
	}
	f.size = mathutil.MaxInt64(f.size, int64(len(b))+off)
	return f.file.WriteAt(b, off)
}
Exemplo n.º 5
0
Arquivo: 2pc.go Projeto: devick/flynn
// NewACIDFiler0 returns a  newly created ACIDFiler0 with WAL in wal.
//
// If the WAL is zero sized then a previous clean shutdown of db is taken for
// granted and no recovery procedure is taken.
//
// If the WAL is of non zero size then it is checked for having a
// commited/fully finished transaction not yet been reflected in db. If such
// transaction exists it's committed to db. If the recovery process finishes
// successfully, the WAL is truncated to zero size and fsync'ed prior to return
// from NewACIDFiler0.
func NewACIDFiler(db Filer, wal *os.File) (r *ACIDFiler0, err error) {
	fi, err := wal.Stat()
	if err != nil {
		return
	}

	r = &ACIDFiler0{wal: wal}

	if fi.Size() != 0 {
		if err = r.recoverDb(db); err != nil {
			return
		}
	}

	acidWriter := (*acidWriter0)(r)

	if r.RollbackFiler, err = NewRollbackFiler(
		db,
		func(sz int64) (err error) {
			// Checkpoint
			if err = acidWriter.writePacket([]interface{}{wpt00Checkpoint, sz}); err != nil {
				return
			}

			if err = r.bwal.Flush(); err != nil {
				return
			}

			r.bwal = nil

			if err = r.wal.Sync(); err != nil {
				return
			}

			wfi, err := r.wal.Stat()
			switch err != nil {
			case true:
				// unexpected, but ignored
			case false:
				r.peakWal = mathutil.MaxInt64(wfi.Size(), r.peakWal)
			}

			// Phase 1 commit complete

			for _, v := range r.data {
				if _, err := db.WriteAt(v.b, v.off); err != nil {
					return err
				}
			}

			if err = db.Truncate(sz); err != nil {
				return
			}

			if err = db.Sync(); err != nil {
				return
			}

			// Phase 2 commit complete

			if !r.testHook {
				if err = r.wal.Truncate(0); err != nil {
					return
				}

				if _, err = r.wal.Seek(0, 0); err != nil {
					return
				}
			}

			r.testHook = false
			return r.wal.Sync()

		},
		acidWriter,
	); err != nil {
		return
	}

	return r, nil
}