1 files changed, 274 insertions, 0 deletions
diff --git a/weed/storage/volume.go b/weed/storage/volume.go
new file mode 100644
index 000000000..707c6e6f8
--- /dev/null
+++ b/weed/storage/volume.go
@@ -0,0 +1,274 @@
+package storage
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"sync"
+)
+
+const (
+	SuperBlockSize = 8
+)
+
+type SuperBlock struct {
+	Version     Version
+	ReplicaType ReplicationType
+}
+
+func (s *SuperBlock) Bytes() []byte {
+	header := make([]byte, SuperBlockSize)
+	header[0] = byte(s.Version)
+	header[1] = s.ReplicaType.Byte()
+	return header
+}
+
+type Volume struct {
+	Id       VolumeId
+	dir      string
+	dataFile *os.File
+	nm       *NeedleMap
+
+	SuperBlock
+
+	accessLock sync.Mutex
+}
+
+func NewVolume(dirname string, id VolumeId, replicationType ReplicationType) (v *Volume, e error) {
+	v = &Volume{dir: dirname, Id: id}
+	v.SuperBlock = SuperBlock{ReplicaType: replicationType}
+	e = v.load(true)
+	return
+}
+func LoadVolumeOnly(dirname string, id VolumeId) (v *Volume, e error) {
+	v = &Volume{dir: dirname, Id: id}
+	v.SuperBlock = SuperBlock{ReplicaType: CopyNil}
+	e = v.load(false)
+	return
+}
+func (v *Volume) load(alsoLoadIndex bool) error {
+	var e error
+	fileName := path.Join(v.dir, v.Id.String())
+	v.dataFile, e = os.OpenFile(fileName+".dat", os.O_RDWR|os.O_CREATE, 0644)
+	if e != nil {
+		return fmt.Errorf("cannot create Volume Data %s.dat: %s", fileName, e)
+	}
+	if v.ReplicaType == CopyNil {
+		if e = v.readSuperBlock(); e != nil {
+			return e
+		}
+	} else {
+		v.maybeWriteSuperBlock()
+	}
+	if alsoLoadIndex {
+		indexFile, ie := os.OpenFile(fileName+".idx", os.O_RDWR|os.O_CREATE, 0644)
+		if ie != nil {
+			return fmt.Errorf("cannot create Volume Data %s.dat: %s", fileName, e)
+		}
+		v.nm = LoadNeedleMap(indexFile)
+	}
+	return nil
+}
+func (v *Volume) Version() Version {
+	return v.SuperBlock.Version
+}
+func (v *Volume) Size() int64 {
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
+	stat, e := v.dataFile.Stat()
+	if e == nil {
+		return stat.Size()
+	}
+	fmt.Printf("Failed to read file size %s %s\n", v.dataFile.Name(), e.Error())
+	return -1
+}
+func (v *Volume) Close() {
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
+	v.nm.Close()
+	v.dataFile.Close()
+}
+func (v *Volume) maybeWriteSuperBlock() {
+	stat, e := v.dataFile.Stat()
+	if e != nil {
+		fmt.Printf("failed to stat datafile %s: %s", v.dataFile, e)
+		return
+	}
+	if stat.Size() == 0 {
+		v.SuperBlock.Version = CurrentVersion
+		v.dataFile.Write(v.SuperBlock.Bytes())
+	}
+}
+func (v *Volume) readSuperBlock() (err error) {
+	v.dataFile.Seek(0, 0)
+	header := make([]byte, SuperBlockSize)
+	if _, e := v.dataFile.Read(header); e != nil {
+		return fmt.Errorf("cannot read superblock: %s", e)
+	}
+	v.SuperBlock, err = ParseSuperBlock(header)
+	return err
+}
+func ParseSuperBlock(header []byte) (superBlock SuperBlock, err error) {
+	superBlock.Version = Version(header[0])
+	if superBlock.ReplicaType, err = NewReplicationTypeFromByte(header[1]); err != nil {
+		err = fmt.Errorf("cannot read replica type: %s", err)
+	}
+	return
+}
+func (v *Volume) NeedToReplicate() bool {
+	return v.ReplicaType.GetCopyCount() > 1
+}
+
+func (v *Volume) write(n *Needle) (size uint32, err error) {
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
+	var offset int64
+	if offset, err = v.dataFile.Seek(0, 2); err != nil {
+		return
+	}
+	if size, err = n.Append(v.dataFile, v.Version()); err != nil {
+		return
+	}
+	nv, ok := v.nm.Get(n.Id)
+	if !ok || int64(nv.Offset)*NeedlePaddingSize < offset {
+		_, err = v.nm.Put(n.Id, uint32(offset/NeedlePaddingSize), n.Size)
+	}
+	return
+}
+func (v *Volume) delete(n *Needle) (uint32, error) {
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
+	nv, ok := v.nm.Get(n.Id)
+	//fmt.Println("key", n.Id, "volume offset", nv.Offset, "data_size", n.Size, "cached size", nv.Size)
+	if ok {
+		v.nm.Delete(n.Id)
+		v.dataFile.Seek(int64(nv.Offset*NeedlePaddingSize), 0)
+		_, err := n.Append(v.dataFile, v.Version())
+		return nv.Size, err
+	}
+	return 0, nil
+}
+
+func (v *Volume) read(n *Needle) (int, error) {
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
+	nv, ok := v.nm.Get(n.Id)
+	if ok && nv.Offset > 0 {
+		v.dataFile.Seek(int64(nv.Offset)*NeedlePaddingSize, 0)
+		return n.Read(v.dataFile, nv.Size, v.Version())
+	}
+	return -1, errors.New("Not Found")
+}
+
+func (v *Volume) garbageLevel() float64 {
+	return float64(v.nm.deletionByteCounter) / float64(v.ContentSize())
+}
+
+func (v *Volume) compact() error {
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
+
+	filePath := path.Join(v.dir, v.Id.String())
+	return v.copyDataAndGenerateIndexFile(filePath+".cpd", filePath+".cpx")
+}
+func (v *Volume) commitCompact() error {
+	v.accessLock.Lock()
+	defer v.accessLock.Unlock()
+	v.dataFile.Close()
+	var e error
+	if e = os.Rename(path.Join(v.dir, v.Id.String()+".cpd"), path.Join(v.dir, v.Id.String()+".dat")); e != nil {
+		return e
+	}
+	if e = os.Rename(path.Join(v.dir, v.Id.String()+".cpx"), path.Join(v.dir, v.Id.String()+".idx")); e != nil {
+		return e
+	}
+	if e = v.load(true); e != nil {
+		return e
+	}
+	return nil
+}
+
+func ScanVolumeFile(dirname string, id VolumeId,
+	visitSuperBlock func(SuperBlock) error,
+	visitNeedle func(n *Needle, offset uint32) error) (err error) {
+	var v *Volume
+	if v, err = LoadVolumeOnly(dirname, id); err != nil {
+		return
+	}
+	if err = visitSuperBlock(v.SuperBlock); err != nil {
+		return
+	}
+
+	version := v.Version()
+
+	offset := uint32(SuperBlockSize)
+	n, rest, e := ReadNeedleHeader(v.dataFile, version)
+	if e != nil {
+		err = fmt.Errorf("cannot read needle header: %s", e)
+		return
+	}
+	for n != nil {
+		if err = n.ReadNeedleBody(v.dataFile, version, rest); err != nil {
+			err = fmt.Errorf("cannot read needle body: %s", err)
+			return
+		}
+		if err = visitNeedle(n, offset); err != nil {
+			return
+		}
+		offset += NeedleHeaderSize + rest
+		if n, rest, err = ReadNeedleHeader(v.dataFile, version); err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return fmt.Errorf("cannot read needle header: %s", err)
+		}
+	}
+
+	return
+}
+
+func (v *Volume) copyDataAndGenerateIndexFile(dstName, idxName string) (err error) {
+	var (
+		dst, idx *os.File
+	)
+	if dst, err = os.OpenFile(dstName, os.O_WRONLY|os.O_CREATE, 0644); err != nil {
+		return
+	}
+	defer dst.Close()
+
+	if idx, err = os.OpenFile(idxName, os.O_WRONLY|os.O_CREATE, 0644); err != nil {
+		return
+	}
+	defer idx.Close()
+
+	nm := NewNeedleMap(idx)
+	new_offset := uint32(SuperBlockSize)
+
+	err = ScanVolumeFile(v.dir, v.Id, func(superBlock SuperBlock) error {
+		_, err = dst.Write(superBlock.Bytes())
+		return err
+	}, func(n *Needle, offset uint32) error {
+		nv, ok := v.nm.Get(n.Id)
+		//log.Println("file size is", n.Size, "rest", rest)
+		if ok && nv.Offset*NeedlePaddingSize == offset {
+			if nv.Size > 0 {
+				if _, err = nm.Put(n.Id, new_offset/NeedlePaddingSize, n.Size); err != nil {
+					return fmt.Errorf("cannot put needle: %s", err)
+				}
+				if _, err = n.Append(dst, v.Version()); err != nil {
+					return fmt.Errorf("cannot append needle: %s", err)
+				}
+				new_offset += n.DiskSize()
+				//log.Println("saving key", n.Id, "volume offset", old_offset, "=>", new_offset, "data_size", n.Size, "rest", rest)
+			}
+		}
+		return nil
+	})
+
+	return
+}
+func (v *Volume) ContentSize() uint64 {
+	return v.nm.fileByteCounter
+}