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package filesys
import (
"io"
"log"
"os"
)
type WrittenIntervalNode struct {
DataOffset int64
TempOffset int64
Size int64
Next *WrittenIntervalNode
}
type WrittenIntervalLinkedList struct {
tempFile *os.File
Head *WrittenIntervalNode
Tail *WrittenIntervalNode
}
type WrittenContinuousIntervals struct {
tempFile *os.File
lastOffset int64
lists []*WrittenIntervalLinkedList
}
func (list *WrittenIntervalLinkedList) Offset() int64 {
return list.Head.DataOffset
}
func (list *WrittenIntervalLinkedList) Size() int64 {
return list.Tail.DataOffset + list.Tail.Size - list.Head.DataOffset
}
func (list *WrittenIntervalLinkedList) addNodeToTail(node *WrittenIntervalNode) {
// 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)
if list.Tail.TempOffset+list.Tail.Size == node.TempOffset {
// already connected
list.Tail.Size += node.Size
} else {
list.Tail.Next = node
list.Tail = node
}
}
func (list *WrittenIntervalLinkedList) addNodeToHead(node *WrittenIntervalNode) {
// 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)
node.Next = list.Head
list.Head = node
}
func (list *WrittenIntervalLinkedList) ReadData(buf []byte, start, stop int64) {
t := list.Head
for {
nodeStart, nodeStop := max(start, t.DataOffset), min(stop, t.DataOffset+t.Size)
if nodeStart < nodeStop {
// glog.V(4).Infof("copying start=%d stop=%d t=[%d,%d) => bufSize=%d nodeStart=%d, nodeStop=%d", start, stop, t.DataOffset, t.DataOffset+t.Size, len(buf), nodeStart, nodeStop)
list.tempFile.ReadAt(buf[nodeStart-start:nodeStop-start], t.TempOffset + nodeStart - t.DataOffset)
}
if t.Next == nil {
break
}
t = t.Next
}
}
func (c *WrittenContinuousIntervals) TotalSize() (total int64) {
for _, list := range c.lists {
total += list.Size()
}
return
}
func (list *WrittenIntervalLinkedList) subList(start, stop int64) *WrittenIntervalLinkedList {
var nodes []*WrittenIntervalNode
for t := list.Head; t != nil; t = t.Next {
nodeStart, nodeStop := max(start, t.DataOffset), min(stop, t.DataOffset+t.Size)
if nodeStart >= nodeStop {
// skip non overlapping WrittenIntervalNode
continue
}
nodes = append(nodes, &WrittenIntervalNode{
TempOffset: t.TempOffset + nodeStart - t.DataOffset,
DataOffset: nodeStart,
Size: nodeStop - nodeStart,
Next: nil,
})
}
for i := 1; i < len(nodes); i++ {
nodes[i-1].Next = nodes[i]
}
return &WrittenIntervalLinkedList{
tempFile: list.tempFile,
Head: nodes[0],
Tail: nodes[len(nodes)-1],
}
}
func (c *WrittenContinuousIntervals) debug() {
log.Printf("++")
for _, l := range c.lists {
log.Printf("++++")
for t := l.Head; ; t = t.Next {
log.Printf("[%d,%d) => [%d,%d) %d", t.DataOffset, t.DataOffset+t.Size, t.TempOffset, t.TempOffset+t.Size, t.Size)
if t.Next == nil {
break
}
}
log.Printf("----")
}
log.Printf("--")
}
func (c *WrittenContinuousIntervals) AddInterval(tempOffset int64, dataSize int, dataOffset int64) {
interval := &WrittenIntervalNode{DataOffset: dataOffset, TempOffset: tempOffset, Size: int64(dataSize)}
// append to the tail and return
if len(c.lists) == 1 {
lastSpan := c.lists[0]
if lastSpan.Tail.DataOffset+lastSpan.Tail.Size == dataOffset {
lastSpan.addNodeToTail(interval)
return
}
}
var newLists []*WrittenIntervalLinkedList
for _, list := range c.lists {
// if list is to the left of new interval, add to the new list
if list.Tail.DataOffset+list.Tail.Size <= interval.DataOffset {
newLists = append(newLists, list)
}
// if list is to the right of new interval, add to the new list
if interval.DataOffset+interval.Size <= list.Head.DataOffset {
newLists = append(newLists, list)
}
// if new interval overwrite the right part of the list
if list.Head.DataOffset < interval.DataOffset && interval.DataOffset < list.Tail.DataOffset+list.Tail.Size {
// create a new list of the left part of existing list
newLists = append(newLists, list.subList(list.Offset(), interval.DataOffset))
}
// if new interval overwrite the left part of the list
if list.Head.DataOffset < interval.DataOffset+interval.Size && interval.DataOffset+interval.Size < list.Tail.DataOffset+list.Tail.Size {
// create a new list of the right part of existing list
newLists = append(newLists, list.subList(interval.DataOffset+interval.Size, list.Tail.DataOffset+list.Tail.Size))
}
// skip anything that is fully overwritten by the new interval
}
c.lists = newLists
// add the new interval to the lists, connecting neighbor lists
var prevList, nextList *WrittenIntervalLinkedList
for _, list := range c.lists {
if list.Head.DataOffset == interval.DataOffset+interval.Size {
nextList = list
break
}
}
for _, list := range c.lists {
if list.Head.DataOffset+list.Size() == dataOffset {
list.addNodeToTail(interval)
prevList = list
break
}
}
if prevList != nil && nextList != nil {
// 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)
prevList.Tail.Next = nextList.Head
prevList.Tail = nextList.Tail
c.removeList(nextList)
} else if nextList != nil {
// add to head was not done when checking
nextList.addNodeToHead(interval)
}
if prevList == nil && nextList == nil {
c.lists = append(c.lists, &WrittenIntervalLinkedList{
tempFile: c.tempFile,
Head: interval,
Tail: interval,
})
}
return
}
func (c *WrittenContinuousIntervals) RemoveLargestIntervalLinkedList() *WrittenIntervalLinkedList {
var maxSize int64
maxIndex := -1
for k, list := range c.lists {
if maxSize <= list.Size() {
maxSize = list.Size()
maxIndex = k
}
}
if maxSize <= 0 {
return nil
}
t := c.lists[maxIndex]
t.tempFile = c.tempFile
c.lists = append(c.lists[0:maxIndex], c.lists[maxIndex+1:]...)
return t
}
func (c *WrittenContinuousIntervals) removeList(target *WrittenIntervalLinkedList) {
index := -1
for k, list := range c.lists {
if list.Offset() == target.Offset() {
index = k
}
}
if index < 0 {
return
}
c.lists = append(c.lists[0:index], c.lists[index+1:]...)
}
func (c *WrittenContinuousIntervals) ReadDataAt(data []byte, startOffset int64) (maxStop int64) {
for _, list := range c.lists {
start := max(startOffset, list.Offset())
stop := min(startOffset+int64(len(data)), list.Offset()+list.Size())
if start < stop {
list.ReadData(data[start-startOffset:], start, stop)
maxStop = max(maxStop, stop)
}
}
return
}
func (l *WrittenIntervalLinkedList) ToReader(start int64, stop int64) io.Reader {
// TODO: optimize this to avoid another loop
var readers []io.Reader
for t := l.Head; ; t = t.Next {
startOffset, stopOffset := max(t.DataOffset, start), min(t.DataOffset+t.Size, stop)
if startOffset < stopOffset {
// glog.V(4).Infof("ToReader read [%d,%d) from [%d,%d) %d", t.DataOffset, t.DataOffset+t.Size, t.TempOffset, t.TempOffset+t.Size, t.Size)
readers = append(readers, newFileSectionReader(l.tempFile, startOffset-t.DataOffset+t.TempOffset, startOffset, stopOffset-startOffset))
}
if t.Next == nil {
break
}
}
if len(readers) == 1 {
return readers[0]
}
return io.MultiReader(readers...)
}
type FileSectionReader struct {
file *os.File
tempStartOffset int64
Offset int64
dataStart int64
dataStop int64
}
var _ = io.Reader(&FileSectionReader{})
func newFileSectionReader(tempfile *os.File, offset int64, dataOffset int64, size int64) *FileSectionReader {
return &FileSectionReader{
file: tempfile,
tempStartOffset: offset,
Offset: offset,
dataStart: dataOffset,
dataStop: dataOffset + size,
}
}
func (f *FileSectionReader) Read(p []byte) (n int, err error) {
remaining := (f.dataStop - f.dataStart) - (f.Offset - f.tempStartOffset)
if remaining <= 0 {
return 0, io.EOF
}
dataLen := min(remaining, int64(len(p)))
// glog.V(4).Infof("reading [%d,%d) from %v [%d,%d)/[%d,%d) %d", f.Offset-f.tempStartOffset+f.dataStart, f.Offset-f.tempStartOffset+f.dataStart+dataLen, f.file.Name(), f.Offset, f.Offset+dataLen, f.tempStartOffset, f.tempStartOffset+f.dataStop-f.dataStart, f.dataStop-f.dataStart)
n, err = f.file.ReadAt(p[:dataLen], f.Offset)
if n > 0 {
f.Offset += int64(n)
} else {
err = io.EOF
}
return
}
|
