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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 }
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