Exemple #1
0
// Synchronize file buffer onto underlying storage device.
func (file *DataFile) Sync() (err error) {
	if err = file.Buf.Unmap(); err != nil {
		return
	}
	file.Buf, err = gommap.Map(file.Fh)
	return
}
Exemple #2
0
// Open a data file that grows by the specified size.
func OpenDataFile(path string, growth int) (file *DataFile, err error) {
	file = &DataFile{Path: path, Growth: growth}
	if file.Fh, err = os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0600); err != nil {
		return
	}
	var size int64
	if size, err = file.Fh.Seek(0, os.SEEK_END); err != nil {
		return
	}
	// Ensure the file is not smaller than file growth
	if file.Size = int(size); file.Size < file.Growth {
		if err = file.EnsureSize(growth); err != nil {
			return
		}
	}
	if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		return
	}
	for i := file.Size - 1; i >= 0; i-- {
		if file.Buf[i] != 0 {
			file.Used = i + 1
			break
		}
	}
	tdlog.Infof("%s opened: %d of %d bytes in-use", path, file.Used, file.Size)
	return
}
Exemple #3
0
// Clear the entire file and resize it to initial size.
func (file *DataFile) Clear() (err error) {
	if err = file.Buf.Unmap(); err != nil {
		return
	} else if err = os.Truncate(file.Path, 0); err != nil {
		return
	} else if err = os.Truncate(file.Path, int64(file.Growth)); err != nil {
		return
	} else if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		return
	}
	file.Used, file.Size = 0, file.Growth
	tdlog.Infof("%s cleared: %d of %d bytes in-use", file.Path, file.Used, file.Size)
	return
}
Exemple #4
0
// Open the file, or create it if non-existing.
func Open(name string, growth uint64) (file *File, err error) {
	if growth < 1 {
		err = errors.New(fmt.Sprintf("Growth size (%d) is too small (opening %s)", growth, name))
	}
	file = &File{Name: name, Growth: growth}
	// Open file (get a handle) and determine its size
	if file.Fh, err = os.OpenFile(name, os.O_CREATE|os.O_RDWR, 0600); err != nil {
		return
	}
	fsize, err := file.Fh.Seek(0, os.SEEK_END)
	if err != nil {
		return
	}
	file.Size = uint64(fsize)
	if file.Size == 0 {
		// Grow the file if it appears too small
		file.CheckSizeAndEnsure(file.Growth)
		return
	}
	// Map the file into memory buffer
	if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		return
	}
	// Bi-sect file buffer to find out how much space in the file is actively in-use
	for low, mid, high := uint64(0), file.Size/2, file.Size; ; {
		switch {
		case high-mid == 1:
			if ConsecutiveTwenty0s(file.Buf[mid:]) {
				if ConsecutiveTwenty0s(file.Buf[mid-1:]) {
					file.UsedSize = mid - 1
				} else {
					file.UsedSize = mid
				}
				return
			}
			file.UsedSize = high
			return
		case ConsecutiveTwenty0s(file.Buf[mid:]):
			high = mid
			mid = low + (mid-low)/2
		default:
			low = mid
			mid = mid + (high-mid)/2
		}
	}
	tdlog.Printf("%s has %d bytes out of %d bytes in-use", name, file.UsedSize, file.Size)
	return
}
Exemple #5
0
// Clear the entire file and resize it to initial size.
func (file *DataFile) Clear() (err error) {
	if err = file.Close(); err != nil {
		return
	} else if err = os.Truncate(file.Path, 0); err != nil {
		return
	} else if file.Fh, err = os.OpenFile(file.Path, os.O_CREATE|os.O_RDWR, 0600); err != nil {
		return
	} else if err = file.overwriteWithZero(0, file.Growth); err != nil {
		return
	} else if file.Buf, err = gommap.Map(file.Fh); err != nil {
		return
	}
	file.Used, file.Size = 0, file.Growth
	tdlog.Infof("%s cleared: %d of %d bytes in-use", file.Path, file.Used, file.Size)
	return
}
Exemple #6
0
// Ensure there is enough room for that many bytes of data.
func (file *DataFile) EnsureSize(more int) (err error) {
	if file.Used+more <= file.Size {
		return
	} else if file.Buf != nil {
		if err = file.Buf.Unmap(); err != nil {
			return
		}
	}
	if err = file.overwriteWithZero(file.Size, file.Growth); err != nil {
		return
	} else if file.Buf, err = gommap.Map(file.Fh); err != nil {
		return
	}
	file.Size += file.Growth
	tdlog.Infof("%s grown: %d -> %d bytes (%d bytes in-use)", file.Path, file.Size-file.Growth, file.Size, file.Used)
	return file.EnsureSize(more)
}
Exemple #7
0
// Ensure there is enough room for that many bytes of data.
func (file *DataFile) EnsureSize(more int) (err error) {
	if file.Used+more <= file.Size {
		return
	}
	if file.Buf != nil {
		if err = file.Buf.Unmap(); err != nil {
			return
		}
	}
	if err = os.Truncate(file.Path, int64(file.Size+file.Growth)); err != nil {
		return
	} else if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		return
	}
	file.Size += file.Growth
	tdlog.Infof("%s grown: %d -> %d bytes (%d bytes in-use)", file.Path, file.Size-file.Growth, file.Size, file.Used)
	return file.EnsureSize(more)
}
Exemple #8
0
// Open a data file that grows by the specified size.
func OpenDataFile(path string, growth int) (file *DataFile, err error) {
	file = &DataFile{Path: path, Growth: growth}
	if file.Fh, err = os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0600); err != nil {
		return
	}
	var size int64
	if size, err = file.Fh.Seek(0, os.SEEK_END); err != nil {
		return
	}
	// Ensure the file is not smaller than file growth
	if file.Size = int(size); file.Size < file.Growth {
		if err = file.EnsureSize(growth); err != nil {
			return
		}
	}
	if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		return
	}
	// Bi-sect file buffer to find out how much space is in-use
	for low, mid, high := 0, file.Size/2, file.Size; ; {
		switch {
		case high-mid == 1:
			if LooksEmpty(file.Buf[mid:]) {
				if mid > 0 && LooksEmpty(file.Buf[mid-1:]) {
					file.Used = mid - 1
				} else {
					file.Used = mid
				}
				return
			}
			file.Used = high
			return
		case LooksEmpty(file.Buf[mid:]):
			high = mid
			mid = low + (mid-low)/2
		default:
			low = mid
			mid = mid + (high-mid)/2
		}
	}
	tdlog.Infof("%s opened: %d of %d bytes in-use", path, file.Used, file.Size)
	return
}
Exemple #9
0
// Ensure that the file has enough room for more data. Grow the file if necessary.
func (file *File) CheckSizeAndEnsure(more uint64) {
	if file.UsedSize+more <= file.Size {
		return
	}
	// Grow the file - unmap the file, truncate and then re-map
	var err error
	if file.Buf != nil {
		if err = file.Buf.Unmap(); err != nil {
			panic(err)
		}
	}
	if err = os.Truncate(file.Name, int64(file.Size+file.Growth)); err != nil {
		panic(err)
	}
	if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		panic(err)
	}
	file.Size += file.Growth
	tdlog.Printf("File %s has grown %d bytes\n", file.Name, file.Growth)
	file.CheckSizeAndEnsure(more)
}
Exemple #10
0
// Ensure that the file has enough room for more data. Grow the file if necessary.
func (file *File) CheckSizeAndEnsure(more uint64) {
	if file.UsedSize+more <= file.Size {
		return
	}
	// Unmap file buffer
	var err error
	if file.Buf != nil {
		if err = file.Buf.Unmap(); err != nil {
			panic(err)
		}
	}
	if _, err = file.Fh.Seek(0, os.SEEK_END); err != nil {
		panic(err)
	}
	// Grow file size (incrementally)
	zeroBuf := make([]byte, FILE_GROWTH_INCREMENTAL)
	for i := uint64(0); i < file.Growth; i += FILE_GROWTH_INCREMENTAL {
		var slice []byte
		if i+FILE_GROWTH_INCREMENTAL > file.Growth {
			slice = zeroBuf[0 : i+FILE_GROWTH_INCREMENTAL-file.Growth]
		} else {
			slice = zeroBuf
		}
		if _, err = file.Fh.Write(slice); err != nil {
			panic(err)
		}
	}
	if err = file.Fh.Sync(); err != nil {
		panic(err)
	}
	// Re-map the (now larger) file buffer
	if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		panic(err)
	}
	file.Size += file.Growth
	tdlog.Printf("File %s has grown %d bytes\n", file.Name, file.Growth)
	file.CheckSizeAndEnsure(more)
}
Exemple #11
0
// Overwrite the file with 0s and return to its initial size.
func (file *File) Clear() {
	var err error
	if err = file.Close(); err != nil {
		panic(err)
	}
	// Shrink to 0 size, then enlarge
	if err = os.Truncate(file.Name, int64(0)); err != nil {
		panic(err)
	}
	if err = os.Truncate(file.Name, int64(file.Growth)); err != nil {
		panic(err)
	}
	// Re-open and reset current size
	if file.Fh, err = os.OpenFile(file.Name, os.O_CREATE|os.O_RDWR, 0600); err != nil {
		panic(err)
	}
	if file.Buf, err = gommap.Map(file.Fh, gommap.RDWR, 0); err != nil {
		panic(err)
	}
	file.UsedSize = 0
	file.Size = file.Growth
	tdlog.Printf("File %s has been cleared, and the size is now %d", file.Name, file.Size)
}