mirror of
https://github.com/seaweedfs/seaweedfs.git
synced 2024-12-06 04:29:02 +08:00
224 lines
6.1 KiB
Go
224 lines
6.1 KiB
Go
package filesys
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import (
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"bytes"
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"io"
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"github.com/chrislusf/seaweedfs/weed/util"
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)
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type IntervalNode struct {
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Data []byte
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Offset int64
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Size int64
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Next *IntervalNode
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}
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type IntervalLinkedList struct {
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Head *IntervalNode
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Tail *IntervalNode
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}
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type ContinuousIntervals struct {
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lists []*IntervalLinkedList
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}
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func (list *IntervalLinkedList) Offset() int64 {
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return list.Head.Offset
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}
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func (list *IntervalLinkedList) Size() int64 {
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return list.Tail.Offset + list.Tail.Size - list.Head.Offset
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}
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func (list *IntervalLinkedList) addNodeToTail(node *IntervalNode) {
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// glog.V(4).Infof("add to tail [%d,%d) + [%d,%d) => [%d,%d)", list.Head.Offset, list.Tail.Offset+list.Tail.Size, node.Offset, node.Offset+node.Size, list.Head.Offset, node.Offset+node.Size)
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list.Tail.Next = node
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list.Tail = node
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}
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func (list *IntervalLinkedList) addNodeToHead(node *IntervalNode) {
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// glog.V(4).Infof("add to head [%d,%d) + [%d,%d) => [%d,%d)", node.Offset, node.Offset+node.Size, list.Head.Offset, list.Tail.Offset+list.Tail.Size, node.Offset, list.Tail.Offset+list.Tail.Size)
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node.Next = list.Head
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list.Head = node
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}
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func (list *IntervalLinkedList) ReadData(buf []byte, start, stop int64) {
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t := list.Head
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for {
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nodeStart, nodeStop := max(start, t.Offset), min(stop, t.Offset+t.Size)
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if nodeStart < nodeStop {
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// glog.V(0).Infof("copying start=%d stop=%d t=[%d,%d) t.data=%d => bufSize=%d nodeStart=%d, nodeStop=%d", start, stop, t.Offset, t.Offset+t.Size, len(t.Data), len(buf), nodeStart, nodeStop)
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copy(buf[nodeStart-start:], t.Data[nodeStart-t.Offset:nodeStop-t.Offset])
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}
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if t.Next == nil {
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break
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}
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t = t.Next
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}
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}
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func (c *ContinuousIntervals) TotalSize() (total int64) {
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for _, list := range c.lists {
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total += list.Size()
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}
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return
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}
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func subList(list *IntervalLinkedList, start, stop int64) *IntervalLinkedList {
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var nodes []*IntervalNode
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for t := list.Head; t != nil; t = t.Next {
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nodeStart, nodeStop := max(start, t.Offset), min(stop, t.Offset+t.Size)
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if nodeStart >= nodeStop {
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// skip non overlapping IntervalNode
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continue
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}
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nodes = append(nodes, &IntervalNode{
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Data: t.Data[nodeStart-t.Offset : nodeStop-t.Offset],
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Offset: nodeStart,
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Size: nodeStop - nodeStart,
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Next: nil,
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})
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}
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for i := 1; i < len(nodes); i++ {
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nodes[i-1].Next = nodes[i]
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}
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return &IntervalLinkedList{
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Head: nodes[0],
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Tail: nodes[len(nodes)-1],
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}
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}
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func (c *ContinuousIntervals) AddInterval(data []byte, offset int64) {
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interval := &IntervalNode{Data: data, Offset: offset, Size: int64(len(data))}
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// append to the tail and return
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if len(c.lists) == 1 {
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lastSpan := c.lists[0]
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if lastSpan.Tail.Offset+lastSpan.Tail.Size == offset {
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lastSpan.addNodeToTail(interval)
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return
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}
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}
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var newLists []*IntervalLinkedList
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for _, list := range c.lists {
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// if list is to the left of new interval, add to the new list
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if list.Tail.Offset+list.Tail.Size <= interval.Offset {
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newLists = append(newLists, list)
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}
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// if list is to the right of new interval, add to the new list
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if interval.Offset+interval.Size <= list.Head.Offset {
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newLists = append(newLists, list)
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}
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// if new interval overwrite the right part of the list
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if list.Head.Offset < interval.Offset && interval.Offset < list.Tail.Offset+list.Tail.Size {
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// create a new list of the left part of existing list
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newLists = append(newLists, subList(list, list.Offset(), interval.Offset))
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}
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// if new interval overwrite the left part of the list
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if list.Head.Offset < interval.Offset+interval.Size && interval.Offset+interval.Size < list.Tail.Offset+list.Tail.Size {
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// create a new list of the right part of existing list
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newLists = append(newLists, subList(list, interval.Offset+interval.Size, list.Tail.Offset+list.Tail.Size))
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}
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// skip anything that is fully overwritten by the new interval
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}
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c.lists = newLists
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// add the new interval to the lists, connecting neighbor lists
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var prevList, nextList *IntervalLinkedList
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for _, list := range c.lists {
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if list.Head.Offset == interval.Offset+interval.Size {
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nextList = list
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break
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}
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}
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for _, list := range c.lists {
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if list.Head.Offset+list.Size() == offset {
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list.addNodeToTail(interval)
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prevList = list
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break
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}
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}
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if prevList != nil && nextList != nil {
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// glog.V(4).Infof("connecting [%d,%d) + [%d,%d) => [%d,%d)", prevList.Head.Offset, prevList.Tail.Offset+prevList.Tail.Size, nextList.Head.Offset, nextList.Tail.Offset+nextList.Tail.Size, prevList.Head.Offset, nextList.Tail.Offset+nextList.Tail.Size)
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prevList.Tail.Next = nextList.Head
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prevList.Tail = nextList.Tail
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c.removeList(nextList)
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} else if nextList != nil {
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// add to head was not done when checking
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nextList.addNodeToHead(interval)
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}
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if prevList == nil && nextList == nil {
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c.lists = append(c.lists, &IntervalLinkedList{
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Head: interval,
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Tail: interval,
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})
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}
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return
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}
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func (c *ContinuousIntervals) RemoveLargestIntervalLinkedList() *IntervalLinkedList {
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var maxSize int64
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maxIndex := -1
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for k, list := range c.lists {
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if maxSize <= list.Size() {
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maxSize = list.Size()
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maxIndex = k
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}
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}
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if maxSize <= 0 {
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return nil
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}
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t := c.lists[maxIndex]
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c.lists = append(c.lists[0:maxIndex], c.lists[maxIndex+1:]...)
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return t
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}
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func (c *ContinuousIntervals) removeList(target *IntervalLinkedList) {
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index := -1
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for k, list := range c.lists {
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if list.Offset() == target.Offset() {
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index = k
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}
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}
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if index < 0 {
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return
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}
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c.lists = append(c.lists[0:index], c.lists[index+1:]...)
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}
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func (c *ContinuousIntervals) ReadDataAt(data []byte, startOffset int64) (maxStop int64) {
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for _, list := range c.lists {
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start := max(startOffset, list.Offset())
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stop := min(startOffset+int64(len(data)), list.Offset()+list.Size())
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if start < stop {
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list.ReadData(data[start-startOffset:], start, stop)
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maxStop = max(maxStop, stop)
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}
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}
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return
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}
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func (l *IntervalLinkedList) ToReader() io.Reader {
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var readers []io.Reader
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t := l.Head
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readers = append(readers, util.NewBytesReader(t.Data))
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for t.Next != nil {
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t = t.Next
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readers = append(readers, bytes.NewReader(t.Data))
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}
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if len(readers) == 1 {
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return readers[0]
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}
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return io.MultiReader(readers...)
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}
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