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zetcd/encode.go
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/* | |
Copyright (c) 2013, Samuel Stauffer <samuel@descolada.com> | |
All rights reserved. | |
Redistribution and use in source and binary forms, with or without | |
modification, are permitted provided that the following conditions are met: | |
* Redistributions of source code must retain the above copyright | |
notice, this list of conditions and the following disclaimer. | |
* Redistributions in binary form must reproduce the above copyright | |
notice, this list of conditions and the following disclaimer in the | |
documentation and/or other materials provided with the distribution. | |
* Neither the name of the author nor the | |
names of its contributors may be used to endorse or promote products | |
derived from this software without specific prior written permission. | |
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND | |
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY | |
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND | |
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
*/ | |
package zetcd | |
import ( | |
"encoding/binary" | |
"errors" | |
"io" | |
"net" | |
"reflect" | |
"runtime" | |
) | |
var ( | |
ErrShortBuffer = errors.New("short buffer") | |
ErrPtrExpected = errors.New("ptr expected") | |
ErrUnhandledFieldType = errors.New("unhandled field type") | |
) | |
type decoder interface { | |
Decode(buf []byte) (int, error) | |
} | |
type encoder interface { | |
Encode(buf []byte) (int, error) | |
} | |
func decodePacket(buf []byte, st interface{}) (n int, err error) { | |
defer func() { | |
if r := recover(); r != nil { | |
if e, ok := r.(runtime.Error); ok && e.Error() == "runtime error: slice bounds out of range" { | |
err = ErrShortBuffer | |
} else { | |
panic(r) | |
} | |
} | |
}() | |
v := reflect.ValueOf(st) | |
if v.Kind() != reflect.Ptr || v.IsNil() { | |
return 0, ErrPtrExpected | |
} | |
return decodePacketValue(buf, v) | |
} | |
func decodePacketValue(buf []byte, v reflect.Value) (int, error) { | |
rv := v | |
kind := v.Kind() | |
if kind == reflect.Ptr { | |
if v.IsNil() { | |
v.Set(reflect.New(v.Type().Elem())) | |
} | |
v = v.Elem() | |
kind = v.Kind() | |
} | |
n := 0 | |
switch kind { | |
default: | |
return n, ErrUnhandledFieldType | |
case reflect.Struct: | |
if de, ok := rv.Interface().(decoder); ok { | |
return de.Decode(buf) | |
} else if de, ok := v.Interface().(decoder); ok { | |
return de.Decode(buf) | |
} else { | |
for i := 0; i < v.NumField(); i++ { | |
field := v.Field(i) | |
n2, err := decodePacketValue(buf[n:], field) | |
n += n2 | |
if err != nil { | |
return n, err | |
} | |
} | |
} | |
case reflect.Bool: | |
v.SetBool(buf[n] != 0) | |
n++ | |
case reflect.Int32: | |
v.SetInt(int64(binary.BigEndian.Uint32(buf[n : n+4]))) | |
n += 4 | |
case reflect.Int64: | |
v.SetInt(int64(binary.BigEndian.Uint64(buf[n : n+8]))) | |
n += 8 | |
case reflect.String: | |
ln := int(binary.BigEndian.Uint32(buf[n : n+4])) | |
v.SetString(string(buf[n+4 : n+4+ln])) | |
n += 4 + ln | |
case reflect.Slice: | |
switch v.Type().Elem().Kind() { | |
default: | |
count := int(binary.BigEndian.Uint32(buf[n : n+4])) | |
n += 4 | |
values := reflect.MakeSlice(v.Type(), count, count) | |
v.Set(values) | |
for i := 0; i < count; i++ { | |
n2, err := decodePacketValue(buf[n:], values.Index(i)) | |
n += n2 | |
if err != nil { | |
return n, err | |
} | |
} | |
case reflect.Uint8: | |
ln := int(int32(binary.BigEndian.Uint32(buf[n : n+4]))) | |
if ln < 0 { | |
n += 4 | |
v.SetBytes(nil) | |
} else { | |
bytes := make([]byte, ln) | |
copy(bytes, buf[n+4:n+4+ln]) | |
v.SetBytes(bytes) | |
n += 4 + ln | |
} | |
} | |
} | |
return n, nil | |
} | |
func encodePacket(buf []byte, st interface{}) (n int, err error) { | |
defer func() { | |
if r := recover(); r != nil { | |
if e, ok := r.(runtime.Error); ok && e.Error() == "runtime error: slice bounds out of range" { | |
err = ErrShortBuffer | |
} else { | |
panic(r) | |
} | |
} | |
}() | |
v := reflect.ValueOf(st) | |
if v.Kind() != reflect.Ptr || v.IsNil() { | |
return 0, ErrPtrExpected | |
} | |
return encodePacketValue(buf, v) | |
} | |
func encodePacketValue(buf []byte, v reflect.Value) (int, error) { | |
rv := v | |
for v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface { | |
v = v.Elem() | |
} | |
n := 0 | |
switch v.Kind() { | |
default: | |
return n, ErrUnhandledFieldType | |
case reflect.Struct: | |
if en, ok := rv.Interface().(encoder); ok { | |
return en.Encode(buf) | |
} else if en, ok := v.Interface().(encoder); ok { | |
return en.Encode(buf) | |
} else { | |
for i := 0; i < v.NumField(); i++ { | |
field := v.Field(i) | |
n2, err := encodePacketValue(buf[n:], field) | |
n += n2 | |
if err != nil { | |
return n, err | |
} | |
} | |
} | |
case reflect.Bool: | |
if v.Bool() { | |
buf[n] = 1 | |
} else { | |
buf[n] = 0 | |
} | |
n++ | |
case reflect.Int32: | |
binary.BigEndian.PutUint32(buf[n:n+4], uint32(v.Int())) | |
n += 4 | |
case reflect.Int64: | |
binary.BigEndian.PutUint64(buf[n:n+8], uint64(v.Int())) | |
n += 8 | |
case reflect.String: | |
str := v.String() | |
binary.BigEndian.PutUint32(buf[n:n+4], uint32(len(str))) | |
copy(buf[n+4:n+4+len(str)], []byte(str)) | |
n += 4 + len(str) | |
case reflect.Slice: | |
switch v.Type().Elem().Kind() { | |
default: | |
count := v.Len() | |
startN := n | |
n += 4 | |
for i := 0; i < count; i++ { | |
n2, err := encodePacketValue(buf[n:], v.Index(i)) | |
n += n2 | |
if err != nil { | |
return n, err | |
} | |
} | |
binary.BigEndian.PutUint32(buf[startN:startN+4], uint32(count)) | |
case reflect.Uint8: | |
if v.IsNil() { | |
binary.BigEndian.PutUint32(buf[n:n+4], uint32(0xffffffff)) | |
n += 4 | |
} else { | |
bytes := v.Bytes() | |
binary.BigEndian.PutUint32(buf[n:n+4], uint32(len(bytes))) | |
copy(buf[n+4:n+4+len(bytes)], bytes) | |
n += 4 + len(bytes) | |
} | |
} | |
} | |
return n, nil | |
} | |
func ReadPacket(zk net.Conn, r interface{}) (string, error) { | |
buf := make([]byte, 256) | |
_, err := io.ReadFull(zk, buf[:4]) | |
if string(buf[:4]) == flwRUOK { | |
return flwRUOK, nil | |
} | |
if err != nil { | |
return "", err | |
} | |
blen := int(binary.BigEndian.Uint32(buf[:4])) | |
if cap(buf) < blen { | |
buf = make([]byte, blen) | |
} | |
_, err = io.ReadFull(zk, buf[:blen]) | |
if err != nil { | |
return "", err | |
} | |
_, err = decodePacket(buf[:blen], r) | |
return "", err | |
} | |
func WritePacket(zk net.Conn, r interface{}) error { | |
buf := make([]byte, 256) | |
n, err := encodePacket(buf[4:], r) | |
if err != nil { | |
return err | |
} | |
binary.BigEndian.PutUint32(buf[:4], uint32(n)) | |
_, err = zk.Write(buf[:n+4]) | |
return err | |
} | |
func (r *MultiRequest) Encode(buf []byte) (int, error) { | |
total := 0 | |
for _, op := range r.Ops { | |
op.Header.Done = false | |
n, err := encodePacketValue(buf[total:], reflect.ValueOf(op)) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
} | |
r.DoneHeader.Done = true | |
n, err := encodePacketValue(buf[total:], reflect.ValueOf(r.DoneHeader)) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
return total, nil | |
} | |
func (r *MultiRequest) Decode(buf []byte) (int, error) { | |
r.Ops = make([]MultiRequestOp, 0) | |
r.DoneHeader = MultiHeader{-1, true, -1} | |
total := 0 | |
for { | |
header := &MultiHeader{} | |
n, err := decodePacketValue(buf[total:], reflect.ValueOf(header)) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
if header.Done { | |
r.DoneHeader = *header | |
break | |
} | |
req := op2req(header.Type) | |
if req == nil { | |
return total, ErrAPIError | |
} | |
n, err = decodePacketValue(buf[total:], reflect.ValueOf(req)) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
r.Ops = append(r.Ops, MultiRequestOp{*header, req}) | |
} | |
return total, nil | |
} | |
func (r *MultiResponse) Encode(buf []byte) (int, error) { | |
total := 0 | |
for _, op := range r.Ops { | |
op.Header.Done = false | |
n, err := encodePacketValue(buf[total:], reflect.ValueOf(op.Header)) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
n = 0 | |
switch op.Header.Type { | |
case opCreate: | |
n, err = encodePacketValue(buf[total:], reflect.ValueOf(op.String)) | |
case opSetData: | |
n, err = encodePacketValue(buf[total:], reflect.ValueOf(op.Stat)) | |
} | |
total += n | |
if err != nil { | |
return total, err | |
} | |
} | |
r.DoneHeader.Done = true | |
n, err := encodePacketValue(buf[total:], reflect.ValueOf(r.DoneHeader)) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
return total, nil | |
} | |
func (r *MultiResponse) Decode(buf []byte) (int, error) { | |
r.Ops = make([]MultiResponseOp, 0) | |
r.DoneHeader = MultiHeader{-1, true, -1} | |
total := 0 | |
for { | |
header := &MultiHeader{} | |
n, err := decodePacketValue(buf[total:], reflect.ValueOf(header)) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
if header.Done { | |
r.DoneHeader = *header | |
break | |
} | |
res := MultiResponseOp{Header: *header} | |
var w reflect.Value | |
switch header.Type { | |
default: | |
return total, ErrAPIError | |
case opCreate: | |
w = reflect.ValueOf(&res.String) | |
case opSetData: | |
res.Stat = new(Stat) | |
w = reflect.ValueOf(res.Stat) | |
case opCheck, opDelete: | |
} | |
if w.IsValid() { | |
n, err := decodePacketValue(buf[total:], w) | |
if err != nil { | |
return total, err | |
} | |
total += n | |
} | |
r.Ops = append(r.Ops, res) | |
} | |
return total, nil | |
} | |
func readBuf(zk net.Conn) ([]byte, uint32, error) { | |
buf := make([]byte, 256) | |
if _, err := io.ReadFull(zk, buf[:4]); err != nil { | |
return nil, 0, err | |
} | |
blen := binary.BigEndian.Uint32(buf[:4]) | |
if cap(buf) < int(blen) { | |
buf = make([]byte, blen) | |
} | |
if _, err := io.ReadFull(zk, buf[:blen]); err != nil { | |
return nil, 0, err | |
} | |
return buf, blen, nil | |
} | |
func readReqOp(zk net.Conn) (Xid, interface{}, error) { | |
buf, blen, err := readBuf(zk) | |
if err != nil { | |
return 0, nil, err | |
} | |
hdr := &requestHeader{} | |
n, herr := decodePacket(buf, hdr) | |
if herr != nil { | |
return 0, nil, herr | |
} | |
op := op2req(hdr.Opcode) | |
_, oerr := decodePacket(buf[n:blen], op) | |
return hdr.Xid, op, oerr | |
} | |
func readRespOp(zk net.Conn, xid2resp func(Xid) interface{}) (*ResponseHeader, interface{}, error) { | |
buf, blen, err := readBuf(zk) | |
if err != nil { | |
return nil, nil, err | |
} | |
hdr := &ResponseHeader{} | |
n, herr := decodePacket(buf, hdr) | |
if herr != nil { | |
return nil, nil, herr | |
} | |
var resp interface{} | |
if hdr.Err != 0 { | |
return hdr, nil, nil | |
} | |
if hdr.Xid == -1 { | |
resp = &WatcherEvent{} | |
} else { | |
resp = xid2resp(hdr.Xid) | |
} | |
if resp == nil { | |
return nil, nil, ErrAPIError | |
} | |
_, oerr := decodePacket(buf[n:blen], resp) | |
return hdr, resp, oerr | |
} |