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filesStorage.go
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filesStorage.go
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package Torrent
import (
"bytes"
"github.com/JRonak/Torrent/MetaData"
"log"
"os"
)
type FileStorage struct {
files []*os.File
meta *MetaData.MetaInfo
MultipleFiles bool
writeChan chan localStruct
}
func (this *FileStorage) Init(meta *MetaData.MetaInfo) bool {
this.meta = meta
this.writeChan = make(chan localStruct, 10)
go this.write()
if meta.Info.Files != nil {
this.MultipleFiles = true
return this.multiInit()
} else {
this.MultipleFiles = false
return this.singleInit()
}
}
func (this *FileStorage) singleInit() bool {
if this.isFileExists(this.meta.Info.Name) {
file, err := os.OpenFile(this.meta.Info.Name, os.O_RDWR, 0766)
if err != nil {
log.Println(err)
return false
}
this.files = append(this.files, file)
return false
}
file := this.createFile(this.meta.Info.Name, this.meta.Size())
this.files = append(this.files, file)
return true
}
func (this *FileStorage) multiInit() bool {
if !this.isDirExists(this.meta.Info.Name) {
this.createDir(this.meta.Info.Name)
}
fileCreated := true
for _, f := range this.meta.Info.Files {
length := len(f.Path)
path := this.meta.Info.Name
for i := 0; i < length-1; i++ {
path += "/" + f.Path[i]
}
filePath := path + "/" + f.Path[length-1]
if !this.isDirExists(path) {
this.createDir(path)
}
if !this.isFileExists(filePath) {
file := this.createFile(filePath, f.Length)
this.files = append(this.files, file)
} else {
file, err := os.OpenFile(filePath, os.O_RDWR, 0777)
if err != nil {
log.Println(err)
continue
}
this.files = append(this.files, file)
fileCreated = false
}
}
return fileCreated
}
func (this *FileStorage) createFile(name string, size int) *os.File {
f, err := os.Create(name)
if err != nil {
log.Println(err)
return nil
}
buf := make([]byte, MB)
for size >= MB {
n, err := f.Write(buf)
if err != nil {
log.Println(err)
return nil
}
size -= n
}
if size > 0 {
_, err := f.Write(buf[:size])
if err != nil {
log.Println(err)
return nil
}
}
return f
}
func (this *FileStorage) createDir(name string) {
os.MkdirAll(name, 0766)
}
func (this *FileStorage) isDirExists(name string) bool {
f, err := os.Open(name)
if err != nil {
return false
}
defer f.Close()
stat, err := f.Stat()
if err != nil {
log.Println(err)
return false
}
if stat.IsDir() {
return true
}
return false
}
func (this *FileStorage) isFileExists(name string) bool {
f, err := os.Open(name)
if err != nil {
return false
}
defer f.Close()
stat, err := f.Stat()
if err != nil {
log.Println(err)
return false
}
if stat.IsDir() {
return false
}
return true
}
//Generic function
func writeFile(file *os.File, data *[]byte, offset int) {
if file != nil {
_, err := file.WriteAt(*data, int64(offset))
if err != nil {
log.Println(err)
}
}
}
func (this *FileStorage) writeMultiple(piece localStruct) {
pSize := len(*piece.data)
pStart := piece.offset * this.meta.Info.PieceLength
pEnd := pStart + pSize
pCurr := pStart
pOffset := 0
fOffset := 0
for i, file := range this.files {
fSize := this.meta.Info.Files[i].Length
fEnd := fOffset + fSize
if fOffset <= pStart && pStart <= fEnd {
if pEnd <= fEnd {
data := *piece.data
data = data[pOffset:]
writeFile(file, &data, (pCurr - fOffset))
break
} else {
data := *piece.data
data = data[pOffset:((fEnd - pCurr) + pOffset)]
writeFile(file, &data, (pCurr - fOffset))
pOffset = (fEnd - pCurr)
pCurr = fEnd
}
}
fOffset = fEnd
}
}
func (this *FileStorage) write() {
for i := range this.writeChan {
if !this.MultipleFiles {
if len(this.files) == 0 {
log.Fatal("file not added")
}
writeFile(this.files[0], i.data, this.meta.Info.PieceLength*i.offset)
} else {
this.tempWriteMulti(i)
}
}
}
func (this *FileStorage) PutBlock(data *[]byte, index int) {
this.writeChan <- localStruct{data: data, offset: index}
}
func (this *FileStorage) GetBlock(index, offset, size int) []byte {
if this.MultipleFiles {
return this.tempReadMultiple(index, offset, size)
} else {
return this.getBlockSingle(index, offset, size)
}
}
func (this *FileStorage) getBlockSingle(index, offset, size int) []byte {
file := this.files[0]
data := make([]byte, size)
n, err := file.ReadAt(data, int64((index*this.meta.Info.PieceLength)+offset))
if err != nil {
log.Println(err)
return nil
}
return data[:n]
}
func (this *FileStorage) getBlockMulti(index, offset, size int) []byte {
pStart := index * this.meta.Info.PieceLength
pEnd := pStart + size
pCurr := pStart
fCurr := 0
buff := bytes.NewBuffer(nil)
for i, file := range this.files {
fSize := this.meta.Info.Files[i].Length
fEnd := fCurr + fSize
if fCurr <= pStart && pStart < fEnd {
if pEnd <= fEnd {
data := make([]byte, (pEnd - pCurr))
file.ReadAt(data, int64(pCurr-fCurr))
buff.Write(data)
break
} else {
data := make([]byte, fEnd-pCurr)
file.ReadAt(data, int64(pCurr-fCurr))
buff.Write(data)
pCurr = fEnd
}
}
fCurr = fEnd
}
return buff.Bytes()
}
func (this *FileStorage) tempWriteMulti(piece localStruct) {
pieceSize := this.meta.Info.PieceLength
pieceStart := pieceSize * piece.offset
pieceEnd := pieceStart + pieceSize
pieceCurrent := pieceStart
fileStart := 0
for i, file := range this.files {
fileEnd := fileStart + this.meta.Info.Files[i].Length
if fileStart <= pieceCurrent && pieceCurrent < fileEnd {
if pieceEnd <= fileEnd {
data := *piece.data
data = data[pieceCurrent-pieceStart:]
_, err := file.WriteAt(data, int64(pieceCurrent-fileStart))
if err != nil {
log.Println(err)
}
break
} else {
data := *piece.data
dataStart := pieceCurrent - pieceStart
data = data[dataStart : dataStart+(fileEnd-pieceCurrent)]
_, err := file.WriteAt(data, int64(pieceCurrent-fileStart))
if err != nil {
log.Println(err)
}
pieceCurrent += (fileEnd - pieceCurrent)
}
}
fileStart = fileEnd
}
}
func (this *FileStorage) tempReadMultiple(index, offset, size int) []byte {
pieceSize := this.meta.Info.PieceLength
pieceStart := pieceSize*index + offset
pieceEnd := pieceStart + size
pieceCurrent := pieceStart
fileStart := 0
buffer := bytes.NewBuffer(nil)
for i, file := range this.files {
fileEnd := fileStart + this.meta.Info.Files[i].Length
if fileStart <= pieceCurrent && pieceCurrent < fileEnd {
if pieceEnd <= fileEnd {
data := make([]byte, pieceEnd-pieceCurrent)
file.ReadAt(data, int64(pieceCurrent-fileStart))
buffer.Write(data)
break
} else {
data := make([]byte, fileEnd-pieceCurrent)
file.ReadAt(data, int64(pieceCurrent-fileStart))
buffer.Write(data)
pieceCurrent += (fileEnd - pieceCurrent)
}
}
fileStart = fileEnd
}
return buffer.Bytes()
}