open-consul/vendor/github.com/SAP/go-hdb/internal/protocol/segment.go

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2018-06-21 14:49:35 +00:00
/*
Copyright 2014 SAP SE
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package protocol
import (
"fmt"
"github.com/SAP/go-hdb/internal/bufio"
)
const (
segmentHeaderSize = 24
)
type commandOptions int8
const (
coNil commandOptions = 0x00
coSelfetchOff commandOptions = 0x01
coScrollableCursorOn commandOptions = 0x02
coNoResultsetCloseNeeded commandOptions = 0x04
coHoldCursorOverCommtit commandOptions = 0x08
coExecuteLocally commandOptions = 0x10
)
var commandOptionsText = map[commandOptions]string{
coSelfetchOff: "selfetchOff",
coScrollableCursorOn: "scrollabeCursorOn",
coNoResultsetCloseNeeded: "noResltsetCloseNeeded",
coHoldCursorOverCommtit: "holdCursorOverCommit",
coExecuteLocally: "executLocally",
}
func (k commandOptions) String() string {
t := make([]string, 0, len(commandOptionsText))
for option, text := range commandOptionsText {
if (k & option) != 0 {
t = append(t, text)
}
}
return fmt.Sprintf("%v", t)
}
//segment header
type segmentHeader struct {
segmentLength int32
segmentOfs int32
noOfParts int16
segmentNo int16
segmentKind segmentKind
messageType messageType
commit bool
commandOptions commandOptions
functionCode functionCode
}
func (h *segmentHeader) String() string {
switch h.segmentKind {
default: //error
return fmt.Sprintf(
"segment length %d segment ofs %d noOfParts %d, segmentNo %d segmentKind %s",
h.segmentLength,
h.segmentOfs,
h.noOfParts,
h.segmentNo,
h.segmentKind,
)
case skRequest:
return fmt.Sprintf(
"segment length %d segment ofs %d noOfParts %d, segmentNo %d segmentKind %s messageType %s commit %t commandOptions %s",
h.segmentLength,
h.segmentOfs,
h.noOfParts,
h.segmentNo,
h.segmentKind,
h.messageType,
h.commit,
h.commandOptions,
)
case skReply:
return fmt.Sprintf(
"segment length %d segment ofs %d noOfParts %d, segmentNo %d segmentKind %s functionCode %s",
h.segmentLength,
h.segmentOfs,
h.noOfParts,
h.segmentNo,
h.segmentKind,
h.functionCode,
)
}
}
// request
func (h *segmentHeader) write(wr *bufio.Writer) error {
wr.WriteInt32(h.segmentLength)
wr.WriteInt32(h.segmentOfs)
wr.WriteInt16(h.noOfParts)
wr.WriteInt16(h.segmentNo)
wr.WriteInt8(int8(h.segmentKind))
switch h.segmentKind {
default: //error
wr.WriteZeroes(11) //segmentHeaderLength
case skRequest:
wr.WriteInt8(int8(h.messageType))
wr.WriteBool(h.commit)
wr.WriteInt8(int8(h.commandOptions))
wr.WriteZeroes(8) //segmentHeaderSize
case skReply:
wr.WriteZeroes(1) //reserved
wr.WriteInt16(int16(h.functionCode))
wr.WriteZeroes(8) //segmentHeaderSize
}
if trace {
outLogger.Printf("write segment header: %s", h)
}
return nil
}
// reply || error
func (h *segmentHeader) read(rd *bufio.Reader) error {
h.segmentLength = rd.ReadInt32()
h.segmentOfs = rd.ReadInt32()
h.noOfParts = rd.ReadInt16()
h.segmentNo = rd.ReadInt16()
h.segmentKind = segmentKind(rd.ReadInt8())
switch h.segmentKind {
default: //error
rd.Skip(11) //segmentHeaderLength
case skRequest:
h.messageType = messageType(rd.ReadInt8())
h.commit = rd.ReadBool()
h.commandOptions = commandOptions(rd.ReadInt8())
rd.Skip(8) //segmentHeaderLength
case skReply:
rd.Skip(1) //reserved
h.functionCode = functionCode(rd.ReadInt16())
rd.Skip(8) //segmentHeaderLength
}
if trace {
outLogger.Printf("read segment header: %s", h)
}
return rd.GetError()
}