support read

weed/mount/page_writer/page_chunk_swapfile.go

@@ -0,0 +1,121 @@
+package page_writer
+
+import (
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/util"
+	"github.com/chrislusf/seaweedfs/weed/util/mem"
+	"os"
+)
+
+var (
+	_ = PageChunk(&SwapFileChunk{})
+)
+
+type ActualChunkIndex int
+
+type SwapFile struct {
+	dir                     string
+	file                    *os.File
+	logicToActualChunkIndex map[LogicChunkIndex]ActualChunkIndex
+	chunkSize               int64
+}
+
+type SwapFileChunk struct {
+	swapfile         *SwapFile
+	usage            *ChunkWrittenIntervalList
+	logicChunkIndex  LogicChunkIndex
+	actualChunkIndex ActualChunkIndex
+}
+
+func NewSwapFile(dir string, chunkSize int64) *SwapFile {
+	return &SwapFile{
+		dir:                     dir,
+		file:                    nil,
+		logicToActualChunkIndex: make(map[LogicChunkIndex]ActualChunkIndex),
+		chunkSize:               chunkSize,
+	}
+}
+func (sf *SwapFile) FreeResource() {
+	if sf.file != nil {
+		sf.file.Close()
+		os.Remove(sf.file.Name())
+	}
+}
+
+func (sf *SwapFile) NewTempFileChunk(logicChunkIndex LogicChunkIndex) (tc *SwapFileChunk) {
+	if sf.file == nil {
+		var err error
+		sf.file, err = os.CreateTemp(sf.dir, "")
+		if err != nil {
+			glog.Errorf("create swap file: %v", err)
+			return nil
+		}
+	}
+	actualChunkIndex, found := sf.logicToActualChunkIndex[logicChunkIndex]
+	if !found {
+		actualChunkIndex = ActualChunkIndex(len(sf.logicToActualChunkIndex))
+		sf.logicToActualChunkIndex[logicChunkIndex] = actualChunkIndex
+	}
+
+	return &SwapFileChunk{
+		swapfile:         sf,
+		usage:            newChunkWrittenIntervalList(),
+		logicChunkIndex:  logicChunkIndex,
+		actualChunkIndex: actualChunkIndex,
+	}
+}
+
+func (sc *SwapFileChunk) FreeResource() {
+}
+
+func (sc *SwapFileChunk) WriteDataAt(src []byte, offset int64) (n int) {
+	innerOffset := offset % sc.swapfile.chunkSize
+	var err error
+	n, err = sc.swapfile.file.WriteAt(src, int64(sc.actualChunkIndex)*sc.swapfile.chunkSize+innerOffset)
+	if err == nil {
+		sc.usage.MarkWritten(innerOffset, innerOffset+int64(n))
+	} else {
+		glog.Errorf("failed to write swap file %s: %v", sc.swapfile.file.Name(), err)
+	}
+	return
+}
+
+func (sc *SwapFileChunk) ReadDataAt(p []byte, off int64) (maxStop int64) {
+	chunkStartOffset := int64(sc.logicChunkIndex) * sc.swapfile.chunkSize
+	for t := sc.usage.head.next; t != sc.usage.tail; t = t.next {
+		logicStart := max(off, chunkStartOffset+t.StartOffset)
+		logicStop := min(off+int64(len(p)), chunkStartOffset+t.stopOffset)
+		if logicStart < logicStop {
+			actualStart := logicStart - chunkStartOffset + int64(sc.actualChunkIndex)*sc.swapfile.chunkSize
+			if _, err := sc.swapfile.file.ReadAt(p[logicStart-off:logicStop-off], actualStart); err != nil {
+				glog.Errorf("failed to reading swap file %s: %v", sc.swapfile.file.Name(), err)
+				break
+			}
+			maxStop = max(maxStop, logicStop)
+		}
+	}
+	return
+}
+
+func (sc *SwapFileChunk) IsComplete() bool {
+	return sc.usage.IsComplete(sc.swapfile.chunkSize)
+}
+
+func (sc *SwapFileChunk) WrittenSize() int64 {
+	return sc.usage.WrittenSize()
+}
+
+func (sc *SwapFileChunk) SaveContent(saveFn SaveToStorageFunc) {
+	if saveFn == nil {
+		return
+	}
+	for t := sc.usage.head.next; t != sc.usage.tail; t = t.next {
+		data := mem.Allocate(int(t.Size()))
+		sc.swapfile.file.ReadAt(data, t.StartOffset+int64(sc.actualChunkIndex)*sc.swapfile.chunkSize)
+		reader := util.NewBytesReader(data)
+		saveFn(reader, int64(sc.logicChunkIndex)*sc.swapfile.chunkSize+t.StartOffset, t.Size(), func() {
+		})
+		mem.Free(data)
+	}
+	sc.usage = newChunkWrittenIntervalList()
+}