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package storage
import (
"fmt"
"io"
"time"
"github.com/chrislusf/seaweedfs/weed/glog"
"github.com/chrislusf/seaweedfs/weed/storage/backend"
"github.com/chrislusf/seaweedfs/weed/storage/needle"
"github.com/chrislusf/seaweedfs/weed/storage/super_block"
. "github.com/chrislusf/seaweedfs/weed/storage/types"
)
// read fills in Needle content by looking up n.Id from NeedleMapper
func (v *Volume) readNeedle(n *needle.Needle, readOption *ReadOption, onReadSizeFn func(size Size)) (int, error) {
v.dataFileAccessLock.RLock()
defer v.dataFileAccessLock.RUnlock()
nv, ok := v.nm.Get(n.Id)
if !ok || nv.Offset.IsZero() {
return -1, ErrorNotFound
}
readSize := nv.Size
if readSize.IsDeleted() {
if readOption != nil && readOption.ReadDeleted && readSize != TombstoneFileSize {
glog.V(3).Infof("reading deleted %s", n.String())
readSize = -readSize
} else {
return -1, ErrorDeleted
}
}
if readSize == 0 {
return 0, nil
}
if onReadSizeFn != nil {
onReadSizeFn(readSize)
}
err := n.ReadData(v.DataBackend, nv.Offset.ToActualOffset(), readSize, v.Version())
if err == needle.ErrorSizeMismatch && OffsetSize == 4 {
err = n.ReadData(v.DataBackend, nv.Offset.ToActualOffset()+int64(MaxPossibleVolumeSize), readSize, v.Version())
}
v.checkReadWriteError(err)
if err != nil {
return 0, err
}
bytesRead := len(n.Data)
if !n.HasTtl() {
return bytesRead, nil
}
ttlMinutes := n.Ttl.Minutes()
if ttlMinutes == 0 {
return bytesRead, nil
}
if !n.HasLastModifiedDate() {
return bytesRead, nil
}
if time.Now().Before(time.Unix(0, int64(n.AppendAtNs)).Add(time.Duration(ttlMinutes) * time.Minute)) {
return bytesRead, nil
}
return -1, ErrorNotFound
}
// read fills in Needle content by looking up n.Id from NeedleMapper
func (v *Volume) ReadNeedleBlob(offset int64, size Size) ([]byte, error) {
v.dataFileAccessLock.RLock()
defer v.dataFileAccessLock.RUnlock()
return needle.ReadNeedleBlob(v.DataBackend, offset, size, v.Version())
}
type VolumeFileScanner interface {
VisitSuperBlock(super_block.SuperBlock) error
ReadNeedleBody() bool
VisitNeedle(n *needle.Needle, offset int64, needleHeader, needleBody []byte) error
}
func ScanVolumeFile(dirname string, collection string, id needle.VolumeId,
needleMapKind NeedleMapKind,
volumeFileScanner VolumeFileScanner) (err error) {
var v *Volume
if v, err = loadVolumeWithoutIndex(dirname, collection, id, needleMapKind); err != nil {
return fmt.Errorf("failed to load volume %d: %v", id, err)
}
if err = volumeFileScanner.VisitSuperBlock(v.SuperBlock); err != nil {
return fmt.Errorf("failed to process volume %d super block: %v", id, err)
}
defer v.Close()
version := v.Version()
offset := int64(v.SuperBlock.BlockSize())
return ScanVolumeFileFrom(version, v.DataBackend, offset, volumeFileScanner)
}
func ScanVolumeFileFrom(version needle.Version, datBackend backend.BackendStorageFile, offset int64, volumeFileScanner VolumeFileScanner) (err error) {
n, nh, rest, e := needle.ReadNeedleHeader(datBackend, version, offset)
if e != nil {
if e == io.EOF {
return nil
}
return fmt.Errorf("cannot read %s at offset %d: %v", datBackend.Name(), offset, e)
}
for n != nil {
var needleBody []byte
if volumeFileScanner.ReadNeedleBody() {
// println("needle", n.Id.String(), "offset", offset, "size", n.Size, "rest", rest)
if needleBody, err = n.ReadNeedleBody(datBackend, version, offset+NeedleHeaderSize, rest); err != nil {
glog.V(0).Infof("cannot read needle head [%d, %d) body [%d, %d) body length %d: %v", offset, offset+NeedleHeaderSize, offset+NeedleHeaderSize, offset+NeedleHeaderSize+rest, rest, err)
// err = fmt.Errorf("cannot read needle body: %v", err)
// return
}
}
err := volumeFileScanner.VisitNeedle(n, offset, nh, needleBody)
if err == io.EOF {
return nil
}
if err != nil {
glog.V(0).Infof("visit needle error: %v", err)
return fmt.Errorf("visit needle error: %v", err)
}
offset += NeedleHeaderSize + rest
glog.V(4).Infof("==> new entry offset %d", offset)
if n, nh, rest, err = needle.ReadNeedleHeader(datBackend, version, offset); err != nil {
if err == io.EOF {
return nil
}
return fmt.Errorf("cannot read needle header at offset %d: %v", offset, err)
}
glog.V(4).Infof("new entry needle size:%d rest:%d", n.Size, rest)
}
return nil
}
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