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package storage
import (
"code.google.com/p/weed-fs/go/glog"
"code.google.com/p/weed-fs/go/util"
"fmt"
"io"
"os"
)
type NeedleMapper interface {
Put(key uint64, offset uint32, size uint32) (int, error)
Get(key uint64) (element *NeedleValue, ok bool)
Delete(key uint64) error
Close()
Destroy() error
ContentSize() uint64
DeletedSize() uint64
FileCount() int
DeletedCount() int
Visit(visit func(NeedleValue) error) (err error)
MaxFileKey() uint64
}
type mapMetric struct {
DeletionCounter int `json:"DeletionCounter"`
FileCounter int `json:"FileCounter"`
DeletionByteCounter uint64 `json:"DeletionByteCounter"`
FileByteCounter uint64 `json:"FileByteCounter"`
MaximumFileKey uint64 `json:"MaxFileKey"`
}
type NeedleMap struct {
indexFile *os.File
m CompactMap
mapMetric
}
func NewNeedleMap(file *os.File) *NeedleMap {
nm := &NeedleMap{
m: NewCompactMap(),
indexFile: file,
}
return nm
}
const (
RowsToRead = 1024
)
func LoadNeedleMap(file *os.File) (*NeedleMap, error) {
nm := NewNeedleMap(file)
e := walkIndexFile(file, func(key uint64, offset, size uint32) error {
if key > nm.MaximumFileKey {
nm.MaximumFileKey = key
}
nm.FileCounter++
nm.FileByteCounter = nm.FileByteCounter + uint64(size)
if offset > 0 {
oldSize := nm.m.Set(Key(key), offset, size)
glog.V(3).Infoln("reading key", key, "offset", offset, "size", size, "oldSize", oldSize)
if oldSize > 0 {
nm.DeletionCounter++
nm.DeletionByteCounter = nm.DeletionByteCounter + uint64(oldSize)
}
} else {
oldSize := nm.m.Delete(Key(key))
glog.V(3).Infoln("removing key", key, "offset", offset, "size", size, "oldSize", oldSize)
nm.DeletionCounter++
nm.DeletionByteCounter = nm.DeletionByteCounter + uint64(oldSize)
}
return nil
})
glog.V(1).Infoln("max file key:", nm.MaximumFileKey)
return nm, e
}
// walks through the index file, calls fn function with each key, offset, size
// stops with the error returned by the fn function
func walkIndexFile(r *os.File, fn func(key uint64, offset, size uint32) error) error {
var readerOffset int64
bytes := make([]byte, 16*RowsToRead)
count, e := r.ReadAt(bytes, readerOffset)
glog.V(3).Infoln("file", r.Name(), "readerOffset", readerOffset, "count", count, "e", e)
readerOffset += int64(count)
var (
key uint64
offset, size uint32
i int
)
for count > 0 && e == nil || e == io.EOF {
for i = 0; i+16 <= count; i += 16 {
key = util.BytesToUint64(bytes[i : i+8])
offset = util.BytesToUint32(bytes[i+8 : i+12])
size = util.BytesToUint32(bytes[i+12 : i+16])
if e = fn(key, offset, size); e != nil {
return e
}
}
if e == io.EOF {
return nil
}
count, e = r.ReadAt(bytes, readerOffset)
glog.V(3).Infoln("file", r.Name(), "readerOffset", readerOffset, "count", count, "e", e)
readerOffset += int64(count)
}
return e
}
func (nm *NeedleMap) Put(key uint64, offset uint32, size uint32) (int, error) {
if key > nm.MaximumFileKey {
nm.MaximumFileKey = key
}
oldSize := nm.m.Set(Key(key), offset, size)
bytes := make([]byte, 16)
util.Uint64toBytes(bytes[0:8], key)
util.Uint32toBytes(bytes[8:12], offset)
util.Uint32toBytes(bytes[12:16], size)
nm.FileCounter++
nm.FileByteCounter = nm.FileByteCounter + uint64(size)
if oldSize > 0 {
nm.DeletionCounter++
nm.DeletionByteCounter = nm.DeletionByteCounter + uint64(oldSize)
}
return nm.indexFile.Write(bytes)
}
func (nm *NeedleMap) Get(key uint64) (element *NeedleValue, ok bool) {
element, ok = nm.m.Get(Key(key))
return
}
func (nm *NeedleMap) Delete(key uint64) error {
nm.DeletionByteCounter = nm.DeletionByteCounter + uint64(nm.m.Delete(Key(key)))
offset, err := nm.indexFile.Seek(0, 1)
if err != nil {
return fmt.Errorf("cannot get position of indexfile: %s", err)
}
bytes := make([]byte, 16)
util.Uint64toBytes(bytes[0:8], key)
util.Uint32toBytes(bytes[8:12], 0)
util.Uint32toBytes(bytes[12:16], 0)
if _, err = nm.indexFile.Write(bytes); err != nil {
plus := ""
if e := nm.indexFile.Truncate(offset); e != nil {
plus = "\ncouldn't truncate index file: " + e.Error()
}
return fmt.Errorf("error writing to indexfile %s: %s%s", nm.indexFile.Name(), err, plus)
}
nm.DeletionCounter++
return nil
}
func (nm *NeedleMap) Close() {
_ = nm.indexFile.Close()
}
func (nm *NeedleMap) Destroy() error {
nm.Close()
return os.Remove(nm.indexFile.Name())
}
func (nm NeedleMap) ContentSize() uint64 {
return nm.FileByteCounter
}
func (nm NeedleMap) DeletedSize() uint64 {
return nm.DeletionByteCounter
}
func (nm NeedleMap) FileCount() int {
return nm.FileCounter
}
func (nm NeedleMap) DeletedCount() int {
return nm.DeletionCounter
}
func (nm *NeedleMap) Visit(visit func(NeedleValue) error) (err error) {
return nm.m.Visit(visit)
}
func (nm NeedleMap) MaxFileKey() uint64 {
return nm.MaximumFileKey
}