forked from datastream/btree
/
serialize.go
222 lines (215 loc) · 5.15 KB
/
serialize.go
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package btree
import (
"bufio"
"code.google.com/p/goprotobuf/proto"
"io"
"log"
"os"
"strconv"
"sync/atomic"
)
// Dump btree to disk
func (t *Btree) Dump(filename string) error {
if !atomic.CompareAndSwapInt32(&t.state, StateNormal, StateDump) {
return nil
}
t.Lock()
snapversion := t.GetVersion()
t.Unlock()
size := len(t.nodes)
fd, err := os.OpenFile(filename+"_"+strconv.Itoa(int(snapversion)), os.O_CREATE|os.O_WRONLY|os.O_SYNC, 0644)
defer fd.Close()
if err != nil {
log.Fatal("file open failed ", filename, "version ", snapversion, err)
return err
}
fb := bufio.NewWriter(fd)
data, err := proto.Marshal(&t.BtreeMetaData)
if err != nil {
log.Fatal("encode tree info error ", err)
} else {
fb.Write(encodefixed32(uint64(len(data))))
if _, err = fb.Write(data); err != nil {
log.Fatal("write file error", err, "at version", snapversion)
return err
}
}
for i := 0; i < size; i++ {
if leaf, ok := t.nodes[i].(*Leaf); ok {
if leaf.GetVersion() <= snapversion {
var data []byte
var err error
if data, err = serializeLeaf(leaf); err != nil {
log.Fatal("encode error ", i, err)
return err
}
fb.Write(encodefixed32(uint64(isLeaf)))
if _, err = fb.Write(data); err != nil {
log.Fatal("write file error", err, "at version", snapversion)
return err
}
}
}
if node, ok := t.nodes[i].(*Node); ok {
if node.GetVersion() <= snapversion {
if data, err := serializeNode(node); err != nil {
log.Fatal("encode error ", i, err)
} else {
fb.Write(encodefixed32(uint64(isNode)))
if _, err = fb.Write(data); err != nil {
log.Fatal("write file error", err, "at version", snapversion)
return err
}
}
}
}
}
if err = fb.Flush(); err != nil {
log.Fatal("file flush failed ", filename, "version ", snapversion, err)
return err
}
atomic.CompareAndSwapInt32(&t.state, StateDump, StateNormal)
return nil
}
func serializeLeaf(leaf *Leaf) ([]byte, error) {
var rst []byte
var data []byte
var err error
if data, err = proto.Marshal(&leaf.IndexMetaData); err != nil {
return rst, err
}
rst = append(rst, encodefixed32(uint64(len(data)))...)
rst = append(rst, data...)
if data, err = proto.Marshal(&leaf.LeafRecordMetaData); err != nil {
return rst, err
}
rst = append(rst, encodefixed32(uint64(len(data)))...)
rst = append(rst, data...)
return rst, nil
}
func serializeNode(node *Node) ([]byte, error) {
var rst []byte
var data []byte
var err error
if data, err = proto.Marshal(&node.IndexMetaData); err != nil {
return rst, err
}
rst = append(rst, encodefixed32(uint64(len(data)))...)
rst = append(rst, data...)
if data, err = proto.Marshal(&node.NodeRecordMetaData); err != nil {
return rst, err
}
rst = append(rst, encodefixed32(uint64(len(data)))...)
rst = append(rst, data...)
return rst, nil
}
// Restore btree from disk
func Restore(filename string) (tree *Btree, err error) {
fd, err := os.Open(filename)
defer fd.Close()
if err != nil {
log.Fatal("file open failed ", filename, err)
return
}
tree = new(Btree)
tree.state = StateNormal
tree.nodes = make([]TreeNode, TreeSize)
reader := bufio.NewReader(fd)
buf, err := readBuf(4, reader)
if err != nil {
return nil, err
}
dataLength := int(decodefixed32(buf))
dataRecord, errs := readBuf(dataLength, reader)
if errs != nil {
return nil, errs
}
tree.BtreeMetaData = BtreeMetaData{}
proto.Unmarshal(dataRecord, &tree.BtreeMetaData)
tree.nodes = make([]TreeNode, tree.GetSize())
for {
// typepart
buf, err = readBuf(4, reader)
dataType := int(decodefixed32(buf))
if err != nil {
break
}
// get index
buf, err = readBuf(4, reader)
if err != nil {
break
}
dataLength = int(decodefixed32(buf))
dataRecord, err = readBuf(dataLength, reader)
if err != nil {
break
}
// get data
buf, err = readBuf(4, reader)
if err != nil {
break
}
dataLength = int(decodefixed32(buf))
dataRecord2, er2 := readBuf(dataLength, reader)
if er2 != nil {
err = er2
break
}
switch dataType {
case isNode:
{
node := new(Node)
proto.Unmarshal(dataRecord, &node.IndexMetaData)
proto.Unmarshal(dataRecord2, &node.NodeRecordMetaData)
tree.nodes[node.GetId()] = node
}
case isLeaf:
{
leaf := new(Leaf)
proto.Unmarshal(dataRecord, &leaf.IndexMetaData)
proto.Unmarshal(dataRecord2, &leaf.LeafRecordMetaData)
tree.nodes[leaf.GetId()] = leaf
}
}
}
if err == io.EOF {
err = nil
}
return
}
func readBuf(dataLength int, reader *bufio.Reader) ([]byte, error) {
dataRecord := make([]byte, dataLength)
index := 0
var err error
for {
var size int
if size, err = reader.Read(dataRecord[index:]); err != nil {
if err == io.EOF {
break
}
log.Println("read socket data failed", err, "read size:", size, "dataLength:", dataLength)
return nil, err
}
index += size
if index == dataLength {
break
}
}
return dataRecord, err
}
func encodefixed32(x uint64) []byte {
var p []byte
p = append(p,
uint8(x),
uint8(x>>8),
uint8(x>>16),
uint8(x>>24))
return p
}
func decodefixed32(num []byte) (x uint64) {
x = uint64(num[0])
x |= uint64(num[1]) << 8
x |= uint64(num[2]) << 16
x |= uint64(num[3]) << 24
return
}