mmap_span: Avoid allocating the span slice on every use

diff --git a/cmd/torrent-verify/main.go b/cmd/torrent-verify/main.go
index 3d56e7d3055c9211e2208b657192714975a22c57..4206756afbbe39eeb6b7eb913a1c671a31be0c64 100644 (file)
--- a/cmd/torrent-verify/main.go
+++ b/cmd/torrent-verify/main.go
@@ -33,7 +33,7 @@ func main() {
                log.Print(err)
        }
        defer devZero.Close()
-       var mMapSpan mmap_span.MMapSpan
+       var mMapSpan *mmap_span.MMapSpan
        for _, file := range metaInfo.Info.Files {
                filename := filepath.Join(append([]string{*dirPath, metaInfo.Info.Name}, file.Path...)...)
                osFile, err := os.Open(filename)
@@ -53,7 +53,7 @@ func main() {
                        log.Printf("file mmap has wrong size: %#v", filename)
                }
                osFile.Close()
-               mMapSpan = append(mMapSpan, goMMap)
+               mMapSpan.Append(goMMap)
        }
        log.Println(len(metaInfo.Info.Files))
        log.Println(mMapSpan.Size())

diff --git a/misc.go b/misc.go
index 96723ed588ca6c9caa634d81d3fa83bfb7b99936..a32404495b18d052067a1d2a2228a70be1654dbd 100644 (file)
--- a/misc.go
+++ b/misc.go
@@ -125,7 +125,8 @@ func upvertedSingleFileInfoFiles(info *metainfo.Info) []metainfo.FileInfo {
        return []metainfo.FileInfo{{Length: info.Length, Path: nil}}
 }
 
-func mmapTorrentData(md *metainfo.Info, location string) (mms mmap_span.MMapSpan, err error) {
+func mmapTorrentData(md *metainfo.Info, location string) (mms *mmap_span.MMapSpan, err error) {
+       mms = &mmap_span.MMapSpan{}
        defer func() {
                if err != nil {
                        mms.Close()
@@ -170,7 +171,7 @@ func mmapTorrentData(md *metainfo.Info, location string) (mms mmap_span.MMapSpan
                        if int64(len(mMap)) != miFile.Length {
                                panic("mmap has wrong length")
                        }
-                       mms = append(mms, mMap)
+                       mms.Append(mMap)
                }()
                if err != nil {
                        return

diff --git a/mmap_span/mmap_span.go b/mmap_span/mmap_span.go
index 66635a128c918b77739019bedfb4cecdeba04dc7..37e63af58970f1383979ad883407c5adf775f36c 100644 (file)
--- a/mmap_span/mmap_span.go
+++ b/mmap_span/mmap_span.go
@@ -14,30 +14,29 @@ func (me segment) Size() int64 {
        return int64(len(me.MMap))
 }
 
-type MMapSpan []gommap.MMap
+type MMapSpan struct {
+       span
+}
 
-func (me MMapSpan) span() (s span) {
-       for _, mmap := range me {
-               s = append(s, segment{mmap})
-       }
-       return
+func (me *MMapSpan) Append(mmap gommap.MMap) {
+       me.span = append(me.span, segment{mmap})
 }
 
 func (me MMapSpan) Close() {
-       for _, mMap := range me {
-               mMap.UnsafeUnmap()
+       for _, mMap := range me.span {
+               mMap.(segment).UnsafeUnmap()
        }
 }
 
 func (me MMapSpan) Size() (ret int64) {
-       for _, seg := range me.span() {
+       for _, seg := range me.span {
                ret += seg.Size()
        }
        return
 }
 
 func (me MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
-       me.span().ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
+       me.ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
                _n := copy(p, interval.(segment).MMap[intervalOffset:])
                p = p[_n:]
                n += _n
@@ -50,7 +49,7 @@ func (me MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
 }
 
 func (me MMapSpan) WriteSectionTo(w io.Writer, off, n int64) (written int64, err error) {
-       me.span().ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
+       me.ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
                var _n int
                p := interval.(segment).MMap[intervalOffset:]
                if n < int64(len(p)) {
@@ -68,7 +67,7 @@ func (me MMapSpan) WriteSectionTo(w io.Writer, off, n int64) (written int64, err
 }
 
 func (me MMapSpan) WriteAt(p []byte, off int64) (n int, err error) {
-       me.span().ApplyTo(off, func(iOff int64, i sizer) (stop bool) {
+       me.ApplyTo(off, func(iOff int64, i sizer) (stop bool) {
                mMap := i.(segment)
                _n := copy(mMap.MMap[iOff:], p)
                // err = mMap.Sync(gommap.MS_ASYNC)

diff --git a/torrent.go b/torrent.go
index 07f7b0b696a0b7d83efcf57e0aed89789ac42bc2..56b738a8d1d3922632dd669e42890832c31a991b 100644 (file)
--- a/torrent.go
+++ b/torrent.go
@@ -60,7 +60,7 @@ type torrent struct {
        length                      int64
        // Prevent mutations to Data memory maps while in use as they're not safe.
        dataLock sync.RWMutex
-       Data     mmap_span.MMapSpan
+       Data     *mmap_span.MMapSpan
 
        Info *MetaInfo
        // Active peer connections.
@@ -459,8 +459,10 @@ func (t *torrent) Close() (err error) {
        t.CeaseNetworking()
        close(t.closing)
        t.dataLock.Lock()
-       t.Data.Close()
-       t.Data = nil
+       if t.Data != nil {
+               t.Data.Close()
+               t.Data = nil
+       }
        t.dataLock.Unlock()
        for _, conn := range t.Conns {
                conn.Close()