add other session providers (#5963)

vendor/github.com/lunny/nodb/dump.go

@@ -0,0 +1,200 @@
+package nodb
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"io"
+	"os"
+
+	"github.com/siddontang/go-snappy/snappy"
+)
+
+//dump format
+// fileIndex(bigendian int64)|filePos(bigendian int64)
+// |keylen(bigendian int32)|key|valuelen(bigendian int32)|value......
+//
+//key and value are both compressed for fast transfer dump on network using snappy
+
+type BinLogAnchor struct {
+	LogFileIndex int64
+	LogPos       int64
+}
+
+func (m *BinLogAnchor) WriteTo(w io.Writer) error {
+	if err := binary.Write(w, binary.BigEndian, m.LogFileIndex); err != nil {
+		return err
+	}
+
+	if err := binary.Write(w, binary.BigEndian, m.LogPos); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (m *BinLogAnchor) ReadFrom(r io.Reader) error {
+	err := binary.Read(r, binary.BigEndian, &m.LogFileIndex)
+	if err != nil {
+		return err
+	}
+
+	err = binary.Read(r, binary.BigEndian, &m.LogPos)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (l *Nodb) DumpFile(path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return l.Dump(f)
+}
+
+func (l *Nodb) Dump(w io.Writer) error {
+	m := new(BinLogAnchor)
+
+	var err error
+
+	l.wLock.Lock()
+	defer l.wLock.Unlock()
+
+	if l.binlog != nil {
+		m.LogFileIndex = l.binlog.LogFileIndex()
+		m.LogPos = l.binlog.LogFilePos()
+	}
+
+	wb := bufio.NewWriterSize(w, 4096)
+	if err = m.WriteTo(wb); err != nil {
+		return err
+	}
+
+	it := l.ldb.NewIterator()
+	it.SeekToFirst()
+
+	compressBuf := make([]byte, 4096)
+
+	var key []byte
+	var value []byte
+	for ; it.Valid(); it.Next() {
+		key = it.RawKey()
+		value = it.RawValue()
+
+		if key, err = snappy.Encode(compressBuf, key); err != nil {
+			return err
+		}
+
+		if err = binary.Write(wb, binary.BigEndian, uint16(len(key))); err != nil {
+			return err
+		}
+
+		if _, err = wb.Write(key); err != nil {
+			return err
+		}
+
+		if value, err = snappy.Encode(compressBuf, value); err != nil {
+			return err
+		}
+
+		if err = binary.Write(wb, binary.BigEndian, uint32(len(value))); err != nil {
+			return err
+		}
+
+		if _, err = wb.Write(value); err != nil {
+			return err
+		}
+	}
+
+	if err = wb.Flush(); err != nil {
+		return err
+	}
+
+	compressBuf = nil
+
+	return nil
+}
+
+func (l *Nodb) LoadDumpFile(path string) (*BinLogAnchor, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return l.LoadDump(f)
+}
+
+func (l *Nodb) LoadDump(r io.Reader) (*BinLogAnchor, error) {
+	l.wLock.Lock()
+	defer l.wLock.Unlock()
+
+	info := new(BinLogAnchor)
+
+	rb := bufio.NewReaderSize(r, 4096)
+
+	err := info.ReadFrom(rb)
+	if err != nil {
+		return nil, err
+	}
+
+	var keyLen uint16
+	var valueLen uint32
+
+	var keyBuf bytes.Buffer
+	var valueBuf bytes.Buffer
+
+	deKeyBuf := make([]byte, 4096)
+	deValueBuf := make([]byte, 4096)
+
+	var key, value []byte
+
+	for {
+		if err = binary.Read(rb, binary.BigEndian, &keyLen); err != nil && err != io.EOF {
+			return nil, err
+		} else if err == io.EOF {
+			break
+		}
+
+		if _, err = io.CopyN(&keyBuf, rb, int64(keyLen)); err != nil {
+			return nil, err
+		}
+
+		if key, err = snappy.Decode(deKeyBuf, keyBuf.Bytes()); err != nil {
+			return nil, err
+		}
+
+		if err = binary.Read(rb, binary.BigEndian, &valueLen); err != nil {
+			return nil, err
+		}
+
+		if _, err = io.CopyN(&valueBuf, rb, int64(valueLen)); err != nil {
+			return nil, err
+		}
+
+		if value, err = snappy.Decode(deValueBuf, valueBuf.Bytes()); err != nil {
+			return nil, err
+		}
+
+		if err = l.ldb.Put(key, value); err != nil {
+			return nil, err
+		}
+
+		keyBuf.Reset()
+		valueBuf.Reset()
+	}
+
+	deKeyBuf = nil
+	deValueBuf = nil
+
+	//if binlog enable, we will delete all binlogs and open a new one for handling simply
+	if l.binlog != nil {
+		l.binlog.PurgeAll()
+	}
+
+	return info, nil
+}