add other session providers (#5963)

vendor/github.com/couchbase/gomemcached/mc_res.go

@@ -0,0 +1,267 @@
+package gomemcached
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"sync"
+)
+
+// MCResponse is memcached response
+type MCResponse struct {
+	// The command opcode of the command that sent the request
+	Opcode CommandCode
+	// The status of the response
+	Status Status
+	// The opaque sent in the request
+	Opaque uint32
+	// The CAS identifier (if applicable)
+	Cas uint64
+	// Extras, key, and body for this response
+	Extras, Key, Body []byte
+	// If true, this represents a fatal condition and we should hang up
+	Fatal bool
+	// Datatype identifier
+	DataType uint8
+}
+
+// A debugging string representation of this response
+func (res MCResponse) String() string {
+	return fmt.Sprintf("{MCResponse status=%v keylen=%d, extralen=%d, bodylen=%d}",
+		res.Status, len(res.Key), len(res.Extras), len(res.Body))
+}
+
+// Response as an error.
+func (res *MCResponse) Error() string {
+	return fmt.Sprintf("MCResponse status=%v, opcode=%v, opaque=%v, msg: %s",
+		res.Status, res.Opcode, res.Opaque, string(res.Body))
+}
+
+func errStatus(e error) Status {
+	status := Status(0xffff)
+	if res, ok := e.(*MCResponse); ok {
+		status = res.Status
+	}
+	return status
+}
+
+// IsNotFound is true if this error represents a "not found" response.
+func IsNotFound(e error) bool {
+	return errStatus(e) == KEY_ENOENT
+}
+
+// IsFatal is false if this error isn't believed to be fatal to a connection.
+func IsFatal(e error) bool {
+	if e == nil {
+		return false
+	}
+	_, ok := isFatal[errStatus(e)]
+	if ok {
+		return true
+	}
+	return false
+}
+
+// Size is number of bytes this response consumes on the wire.
+func (res *MCResponse) Size() int {
+	return HDR_LEN + len(res.Extras) + len(res.Key) + len(res.Body)
+}
+
+func (res *MCResponse) fillHeaderBytes(data []byte) int {
+	pos := 0
+	data[pos] = RES_MAGIC
+	pos++
+	data[pos] = byte(res.Opcode)
+	pos++
+	binary.BigEndian.PutUint16(data[pos:pos+2],
+		uint16(len(res.Key)))
+	pos += 2
+
+	// 4
+	data[pos] = byte(len(res.Extras))
+	pos++
+	// Data type
+	if res.DataType != 0 {
+		data[pos] = byte(res.DataType)
+	} else {
+		data[pos] = 0
+	}
+	pos++
+	binary.BigEndian.PutUint16(data[pos:pos+2], uint16(res.Status))
+	pos += 2
+
+	// 8
+	binary.BigEndian.PutUint32(data[pos:pos+4],
+		uint32(len(res.Body)+len(res.Key)+len(res.Extras)))
+	pos += 4
+
+	// 12
+	binary.BigEndian.PutUint32(data[pos:pos+4], res.Opaque)
+	pos += 4
+
+	// 16
+	binary.BigEndian.PutUint64(data[pos:pos+8], res.Cas)
+	pos += 8
+
+	if len(res.Extras) > 0 {
+		copy(data[pos:pos+len(res.Extras)], res.Extras)
+		pos += len(res.Extras)
+	}
+
+	if len(res.Key) > 0 {
+		copy(data[pos:pos+len(res.Key)], res.Key)
+		pos += len(res.Key)
+	}
+
+	return pos
+}
+
+// HeaderBytes will get just the header bytes for this response.
+func (res *MCResponse) HeaderBytes() []byte {
+	data := make([]byte, HDR_LEN+len(res.Extras)+len(res.Key))
+
+	res.fillHeaderBytes(data)
+
+	return data
+}
+
+// Bytes will return the actual bytes transmitted for this response.
+func (res *MCResponse) Bytes() []byte {
+	data := make([]byte, res.Size())
+
+	pos := res.fillHeaderBytes(data)
+
+	copy(data[pos:pos+len(res.Body)], res.Body)
+
+	return data
+}
+
+// Transmit will send this response message across a writer.
+func (res *MCResponse) Transmit(w io.Writer) (n int, err error) {
+	if len(res.Body) < 128 {
+		n, err = w.Write(res.Bytes())
+	} else {
+		n, err = w.Write(res.HeaderBytes())
+		if err == nil {
+			m := 0
+			m, err = w.Write(res.Body)
+			m += n
+		}
+	}
+	return
+}
+
+// Receive will fill this MCResponse with the data from this reader.
+func (res *MCResponse) Receive(r io.Reader, hdrBytes []byte) (n int, err error) {
+	if len(hdrBytes) < HDR_LEN {
+		hdrBytes = []byte{
+			0, 0, 0, 0, 0, 0, 0, 0,
+			0, 0, 0, 0, 0, 0, 0, 0,
+			0, 0, 0, 0, 0, 0, 0, 0}
+	}
+	n, err = io.ReadFull(r, hdrBytes)
+	if err != nil {
+		return n, err
+	}
+
+	if hdrBytes[0] != RES_MAGIC && hdrBytes[0] != REQ_MAGIC {
+		return n, fmt.Errorf("bad magic: 0x%02x", hdrBytes[0])
+	}
+
+	klen := int(binary.BigEndian.Uint16(hdrBytes[2:4]))
+	elen := int(hdrBytes[4])
+
+	res.Opcode = CommandCode(hdrBytes[1])
+	res.DataType = uint8(hdrBytes[5])
+	res.Status = Status(binary.BigEndian.Uint16(hdrBytes[6:8]))
+	res.Opaque = binary.BigEndian.Uint32(hdrBytes[12:16])
+	res.Cas = binary.BigEndian.Uint64(hdrBytes[16:24])
+
+	bodyLen := int(binary.BigEndian.Uint32(hdrBytes[8:12])) - (klen + elen)
+
+	//defer function to debug the panic seen with MB-15557
+	defer func() {
+		if e := recover(); e != nil {
+			err = fmt.Errorf(`Panic in Receive. Response %v \n
+                        key len %v extra len %v bodylen %v`, res, klen, elen, bodyLen)
+		}
+	}()
+
+	buf := make([]byte, klen+elen+bodyLen)
+	m, err := io.ReadFull(r, buf)
+	if err == nil {
+		res.Extras = buf[0:elen]
+		res.Key = buf[elen : klen+elen]
+		res.Body = buf[klen+elen:]
+	}
+
+	return n + m, err
+}
+
+type MCResponsePool struct {
+	pool *sync.Pool
+}
+
+func NewMCResponsePool() *MCResponsePool {
+	rv := &MCResponsePool{
+		pool: &sync.Pool{
+			New: func() interface{} {
+				return &MCResponse{}
+			},
+		},
+	}
+
+	return rv
+}
+
+func (this *MCResponsePool) Get() *MCResponse {
+	return this.pool.Get().(*MCResponse)
+}
+
+func (this *MCResponsePool) Put(r *MCResponse) {
+	if r == nil {
+		return
+	}
+
+	r.Extras = nil
+	r.Key = nil
+	r.Body = nil
+	r.Fatal = false
+
+	this.pool.Put(r)
+}
+
+type StringMCResponsePool struct {
+	pool *sync.Pool
+	size int
+}
+
+func NewStringMCResponsePool(size int) *StringMCResponsePool {
+	rv := &StringMCResponsePool{
+		pool: &sync.Pool{
+			New: func() interface{} {
+				return make(map[string]*MCResponse, size)
+			},
+		},
+		size: size,
+	}
+
+	return rv
+}
+
+func (this *StringMCResponsePool) Get() map[string]*MCResponse {
+	return this.pool.Get().(map[string]*MCResponse)
+}
+
+func (this *StringMCResponsePool) Put(m map[string]*MCResponse) {
+	if m == nil || len(m) > 2*this.size {
+		return
+	}
+
+	for k := range m {
+		m[k] = nil
+		delete(m, k)
+	}
+
+	this.pool.Put(m)
+}