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f3cacc1 Apr 7, 2018
@ugorji @client9
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// Copyright (c) 2012-2018 Ugorji Nwoke. All rights reserved.
// Use of this source code is governed by a MIT license found in the LICENSE file.
package codec
import (
"encoding"
"errors"
"fmt"
"io"
"reflect"
"strconv"
"sync"
"time"
)
// Some tagging information for error messages.
const (
msgBadDesc = "unrecognized descriptor byte"
msgDecCannotExpandArr = "cannot expand go array from %v to stream length: %v"
)
const decDefSliceCap = 8
const decDefChanCap = 64 // should be large, as cap cannot be expanded
const decScratchByteArrayLen = cacheLineSize - 8
var (
errstrOnlyMapOrArrayCanDecodeIntoStruct = "only encoded map or array can be decoded into a struct"
errstrCannotDecodeIntoNil = "cannot decode into nil"
errmsgExpandSliceOverflow = "expand slice: slice overflow"
errmsgExpandSliceCannotChange = "expand slice: cannot change"
errDecoderNotInitialized = errors.New("Decoder not initialized")
errDecUnreadByteNothingToRead = errors.New("cannot unread - nothing has been read")
errDecUnreadByteLastByteNotRead = errors.New("cannot unread - last byte has not been read")
errDecUnreadByteUnknown = errors.New("cannot unread - reason unknown")
)
// decReader abstracts the reading source, allowing implementations that can
// read from an io.Reader or directly off a byte slice with zero-copying.
type decReader interface {
unreadn1()
// readx will use the implementation scratch buffer if possible i.e. n < len(scratchbuf), OR
// just return a view of the []byte being decoded from.
// Ensure you call detachZeroCopyBytes later if this needs to be sent outside codec control.
readx(n int) []byte
readb([]byte)
readn1() uint8
numread() int // number of bytes read
track()
stopTrack() []byte
// skip will skip any byte that matches, and return the first non-matching byte
skip(accept *bitset256) (token byte)
// readTo will read any byte that matches, stopping once no-longer matching.
readTo(in []byte, accept *bitset256) (out []byte)
// readUntil will read, only stopping once it matches the 'stop' byte.
readUntil(in []byte, stop byte) (out []byte)
}
type decDriver interface {
// this will check if the next token is a break.
CheckBreak() bool
// Note: TryDecodeAsNil should be careful not to share any temporary []byte with
// the rest of the decDriver. This is because sometimes, we optimize by holding onto
// a transient []byte, and ensuring the only other call we make to the decDriver
// during that time is maybe a TryDecodeAsNil() call.
TryDecodeAsNil() bool
// vt is one of: Bytes, String, Nil, Slice or Map. Return unSet if not known.
ContainerType() (vt valueType)
// IsBuiltinType(rt uintptr) bool
// DecodeNaked will decode primitives (number, bool, string, []byte) and RawExt.
// For maps and arrays, it will not do the decoding in-band, but will signal
// the decoder, so that is done later, by setting the decNaked.valueType field.
//
// Note: Numbers are decoded as int64, uint64, float64 only (no smaller sized number types).
// for extensions, DecodeNaked must read the tag and the []byte if it exists.
// if the []byte is not read, then kInterfaceNaked will treat it as a Handle
// that stores the subsequent value in-band, and complete reading the RawExt.
//
// extensions should also use readx to decode them, for efficiency.
// kInterface will extract the detached byte slice if it has to pass it outside its realm.
DecodeNaked()
// Deprecated: use DecodeInt64 and DecodeUint64 instead
// DecodeInt(bitsize uint8) (i int64)
// DecodeUint(bitsize uint8) (ui uint64)
DecodeInt64() (i int64)
DecodeUint64() (ui uint64)
DecodeFloat64() (f float64)
DecodeBool() (b bool)
// DecodeString can also decode symbols.
// It looks redundant as DecodeBytes is available.
// However, some codecs (e.g. binc) support symbols and can
// return a pre-stored string value, meaning that it can bypass
// the cost of []byte->string conversion.
DecodeString() (s string)
DecodeStringAsBytes() (v []byte)
// DecodeBytes may be called directly, without going through reflection.
// Consequently, it must be designed to handle possible nil.
DecodeBytes(bs []byte, zerocopy bool) (bsOut []byte)
// DecodeBytes(bs []byte, isstring, zerocopy bool) (bsOut []byte)
// decodeExt will decode into a *RawExt or into an extension.
DecodeExt(v interface{}, xtag uint64, ext Ext) (realxtag uint64)
// decodeExt(verifyTag bool, tag byte) (xtag byte, xbs []byte)
DecodeTime() (t time.Time)
ReadArrayStart() int
ReadArrayElem()
ReadArrayEnd()
ReadMapStart() int
ReadMapElemKey()
ReadMapElemValue()
ReadMapEnd()
reset()
uncacheRead()
}
type decDriverNoopContainerReader struct{}
func (x decDriverNoopContainerReader) ReadArrayStart() (v int) { return }
func (x decDriverNoopContainerReader) ReadArrayElem() {}
func (x decDriverNoopContainerReader) ReadArrayEnd() {}
func (x decDriverNoopContainerReader) ReadMapStart() (v int) { return }
func (x decDriverNoopContainerReader) ReadMapElemKey() {}
func (x decDriverNoopContainerReader) ReadMapElemValue() {}
func (x decDriverNoopContainerReader) ReadMapEnd() {}
func (x decDriverNoopContainerReader) CheckBreak() (v bool) { return }
// func (x decNoSeparator) uncacheRead() {}
// DecodeOptions captures configuration options during decode.
type DecodeOptions struct {
// MapType specifies type to use during schema-less decoding of a map in the stream.
// If nil (unset), we default to map[string]interface{} iff json handle and MapStringAsKey=true,
// else map[interface{}]interface{}.
MapType reflect.Type
// SliceType specifies type to use during schema-less decoding of an array in the stream.
// If nil (unset), we default to []interface{} for all formats.
SliceType reflect.Type
// MaxInitLen defines the maxinum initial length that we "make" a collection
// (string, slice, map, chan). If 0 or negative, we default to a sensible value
// based on the size of an element in the collection.
//
// For example, when decoding, a stream may say that it has 2^64 elements.
// We should not auto-matically provision a slice of that size, to prevent Out-Of-Memory crash.
// Instead, we provision up to MaxInitLen, fill that up, and start appending after that.
MaxInitLen int
// ReaderBufferSize is the size of the buffer used when reading.
//
// if > 0, we use a smart buffer internally for performance purposes.
ReaderBufferSize int
// If ErrorIfNoField, return an error when decoding a map
// from a codec stream into a struct, and no matching struct field is found.
ErrorIfNoField bool
// If ErrorIfNoArrayExpand, return an error when decoding a slice/array that cannot be expanded.
// For example, the stream contains an array of 8 items, but you are decoding into a [4]T array,
// or you are decoding into a slice of length 4 which is non-addressable (and so cannot be set).
ErrorIfNoArrayExpand bool
// If SignedInteger, use the int64 during schema-less decoding of unsigned values (not uint64).
SignedInteger bool
// MapValueReset controls how we decode into a map value.
//
// By default, we MAY retrieve the mapping for a key, and then decode into that.
// However, especially with big maps, that retrieval may be expensive and unnecessary
// if the stream already contains all that is necessary to recreate the value.
//
// If true, we will never retrieve the previous mapping,
// but rather decode into a new value and set that in the map.
//
// If false, we will retrieve the previous mapping if necessary e.g.
// the previous mapping is a pointer, or is a struct or array with pre-set state,
// or is an interface.
MapValueReset bool
// SliceElementReset: on decoding a slice, reset the element to a zero value first.
//
// concern: if the slice already contained some garbage, we will decode into that garbage.
SliceElementReset bool
// InterfaceReset controls how we decode into an interface.
//
// By default, when we see a field that is an interface{...},
// or a map with interface{...} value, we will attempt decoding into the
// "contained" value.
//
// However, this prevents us from reading a string into an interface{}
// that formerly contained a number.
//
// If true, we will decode into a new "blank" value, and set that in the interface.
// If false, we will decode into whatever is contained in the interface.
InterfaceReset bool
// InternString controls interning of strings during decoding.
//
// Some handles, e.g. json, typically will read map keys as strings.
// If the set of keys are finite, it may help reduce allocation to
// look them up from a map (than to allocate them afresh).
//
// Note: Handles will be smart when using the intern functionality.
// Every string should not be interned.
// An excellent use-case for interning is struct field names,
// or map keys where key type is string.
InternString bool
// PreferArrayOverSlice controls whether to decode to an array or a slice.
//
// This only impacts decoding into a nil interface{}.
// Consequently, it has no effect on codecgen.
//
// *Note*: This only applies if using go1.5 and above,
// as it requires reflect.ArrayOf support which was absent before go1.5.
PreferArrayOverSlice bool
// DeleteOnNilMapValue controls how to decode a nil value in the stream.
//
// If true, we will delete the mapping of the key.
// Else, just set the mapping to the zero value of the type.
DeleteOnNilMapValue bool
}
// ------------------------------------
type bufioDecReader struct {
buf []byte
r io.Reader
c int // cursor
n int // num read
err error
tr []byte
trb bool
b [4]byte
}
func (z *bufioDecReader) reset(r io.Reader) {
z.r, z.c, z.n, z.err, z.trb = r, 0, 0, nil, false
if z.tr != nil {
z.tr = z.tr[:0]
}
}
func (z *bufioDecReader) Read(p []byte) (n int, err error) {
if z.err != nil {
return 0, z.err
}
p0 := p
n = copy(p, z.buf[z.c:])
z.c += n
if z.c == len(z.buf) {
z.c = 0
}
z.n += n
if len(p) == n {
if z.c == 0 {
z.buf = z.buf[:1]
z.buf[0] = p[len(p)-1]
z.c = 1
}
if z.trb {
z.tr = append(z.tr, p0[:n]...)
}
return
}
p = p[n:]
var n2 int
// if we are here, then z.buf is all read
if len(p) > len(z.buf) {
n2, err = decReadFull(z.r, p)
n += n2
z.n += n2
z.err = err
// don't return EOF if some bytes were read. keep for next time.
if n > 0 && err == io.EOF {
err = nil
}
// always keep last byte in z.buf
z.buf = z.buf[:1]
z.buf[0] = p[len(p)-1]
z.c = 1
if z.trb {
z.tr = append(z.tr, p0[:n]...)
}
return
}
// z.c is now 0, and len(p) <= len(z.buf)
for len(p) > 0 && z.err == nil {
// println("len(p) loop starting ... ")
z.c = 0
z.buf = z.buf[0:cap(z.buf)]
n2, err = z.r.Read(z.buf)
if n2 > 0 {
if err == io.EOF {
err = nil
}
z.buf = z.buf[:n2]
n2 = copy(p, z.buf)
z.c = n2
n += n2
z.n += n2
p = p[n2:]
}
z.err = err
// println("... len(p) loop done")
}
if z.c == 0 {
z.buf = z.buf[:1]
z.buf[0] = p[len(p)-1]
z.c = 1
}
if z.trb {
z.tr = append(z.tr, p0[:n]...)
}
return
}
func (z *bufioDecReader) ReadByte() (b byte, err error) {
z.b[0] = 0
_, err = z.Read(z.b[:1])
b = z.b[0]
return
}
func (z *bufioDecReader) UnreadByte() (err error) {
if z.err != nil {
return z.err
}
if z.c > 0 {
z.c--
z.n--
if z.trb {
z.tr = z.tr[:len(z.tr)-1]
}
return
}
return errDecUnreadByteNothingToRead
}
func (z *bufioDecReader) numread() int {
return z.n
}
func (z *bufioDecReader) readx(n int) (bs []byte) {
if n <= 0 || z.err != nil {
return
}
if z.c+n <= len(z.buf) {
bs = z.buf[z.c : z.c+n]
z.n += n
z.c += n
if z.trb {
z.tr = append(z.tr, bs...)
}
return
}
bs = make([]byte, n)
_, err := z.Read(bs)
if err != nil {
panic(err)
}
return
}
func (z *bufioDecReader) readb(bs []byte) {
_, err := z.Read(bs)
if err != nil {
panic(err)
}
}
// func (z *bufioDecReader) readn1eof() (b uint8, eof bool) {
// b, err := z.ReadByte()
// if err != nil {
// if err == io.EOF {
// eof = true
// } else {
// panic(err)
// }
// }
// return
// }
func (z *bufioDecReader) readn1() (b uint8) {
b, err := z.ReadByte()
if err != nil {
panic(err)
}
return
}
func (z *bufioDecReader) search(in []byte, accept *bitset256, stop, flag uint8) (token byte, out []byte) {
// flag: 1 (skip), 2 (readTo), 4 (readUntil)
if flag == 4 {
for i := z.c; i < len(z.buf); i++ {
if z.buf[i] == stop {
token = z.buf[i]
z.n = z.n + (i - z.c) - 1
i++
out = z.buf[z.c:i]
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...)
}
z.c = i
return
}
}
} else {
for i := z.c; i < len(z.buf); i++ {
if !accept.isset(z.buf[i]) {
token = z.buf[i]
z.n = z.n + (i - z.c) - 1
if flag == 1 {
i++
} else {
out = z.buf[z.c:i]
}
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...)
}
z.c = i
return
}
}
}
z.n += len(z.buf) - z.c
if flag != 1 {
out = append(in, z.buf[z.c:]...)
}
if z.trb {
z.tr = append(z.tr, z.buf[z.c:]...)
}
var n2 int
if z.err != nil {
return
}
for {
z.c = 0
z.buf = z.buf[0:cap(z.buf)]
n2, z.err = z.r.Read(z.buf)
if n2 > 0 && z.err != nil {
z.err = nil
}
z.buf = z.buf[:n2]
if flag == 4 {
for i := 0; i < n2; i++ {
if z.buf[i] == stop {
token = z.buf[i]
z.n += i - 1
i++
out = append(out, z.buf[z.c:i]...)
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...)
}
z.c = i
return
}
}
} else {
for i := 0; i < n2; i++ {
if !accept.isset(z.buf[i]) {
token = z.buf[i]
z.n += i - 1
if flag == 1 {
i++
}
if flag != 1 {
out = append(out, z.buf[z.c:i]...)
}
if z.trb {
z.tr = append(z.tr, z.buf[z.c:i]...)
}
z.c = i
return
}
}
}
if flag != 1 {
out = append(out, z.buf[:n2]...)
}
z.n += n2
if z.err != nil {
return
}
if z.trb {
z.tr = append(z.tr, z.buf[:n2]...)
}
}
}
func (z *bufioDecReader) skip(accept *bitset256) (token byte) {
token, _ = z.search(nil, accept, 0, 1)
return
}
func (z *bufioDecReader) readTo(in []byte, accept *bitset256) (out []byte) {
_, out = z.search(in, accept, 0, 2)
return
}
func (z *bufioDecReader) readUntil(in []byte, stop byte) (out []byte) {
_, out = z.search(in, nil, stop, 4)
return
}
func (z *bufioDecReader) unreadn1() {
err := z.UnreadByte()
if err != nil {
panic(err)
}
}
func (z *bufioDecReader) track() {
if z.tr != nil {
z.tr = z.tr[:0]
}
z.trb = true
}
func (z *bufioDecReader) stopTrack() (bs []byte) {
z.trb = false
return z.tr
}
// ioDecReader is a decReader that reads off an io.Reader.
//
// It also has a fallback implementation of ByteScanner if needed.
type ioDecReader struct {
r io.Reader // the reader passed in
rr io.Reader
br io.ByteScanner
l byte // last byte
ls byte // last byte status. 0: init-canDoNothing, 1: canRead, 2: canUnread
trb bool // tracking bytes turned on
_ bool
b [4]byte // tiny buffer for reading single bytes
x [scratchByteArrayLen]byte // for: get struct field name, swallow valueTypeBytes, etc
n int // num read
tr []byte // tracking bytes read
}
func (z *ioDecReader) reset(r io.Reader) {
z.r = r
z.rr = r
z.l, z.ls, z.n, z.trb = 0, 0, 0, false
if z.tr != nil {
z.tr = z.tr[:0]
}
var ok bool
if z.br, ok = r.(io.ByteScanner); !ok {
z.br = z
z.rr = z
}
}
func (z *ioDecReader) Read(p []byte) (n int, err error) {
if len(p) == 0 {
return
}
var firstByte bool
if z.ls == 1 {
z.ls = 2
p[0] = z.l
if len(p) == 1 {
n = 1
return
}
firstByte = true
p = p[1:]
}
n, err = z.r.Read(p)
if n > 0 {
if err == io.EOF && n == len(p) {
err = nil // read was successful, so postpone EOF (till next time)
}
z.l = p[n-1]
z.ls = 2
}
if firstByte {
n++
}
return
}
func (z *ioDecReader) ReadByte() (c byte, err error) {
n, err := z.Read(z.b[:1])
if n == 1 {
c = z.b[0]
if err == io.EOF {
err = nil // read was successful, so postpone EOF (till next time)
}
}
return
}
func (z *ioDecReader) UnreadByte() (err error) {
switch z.ls {
case 2:
z.ls = 1
case 0:
err = errDecUnreadByteNothingToRead
case 1:
err = errDecUnreadByteLastByteNotRead
default:
err = errDecUnreadByteUnknown
}
return
}
func (z *ioDecReader) numread() int {
return z.n
}
func (z *ioDecReader) readx(n int) (bs []byte) {
if n <= 0 {
return
}
if n < len(z.x) {
bs = z.x[:n]
} else {
bs = make([]byte, n)
}
if _, err := decReadFull(z.rr, bs); err != nil {
panic(err)
}
z.n += len(bs)
if z.trb {
z.tr = append(z.tr, bs...)
}
return
}
func (z *ioDecReader) readb(bs []byte) {
// if len(bs) == 0 {
// return
// }
if _, err := decReadFull(z.rr, bs); err != nil {
panic(err)
}
z.n += len(bs)
if z.trb {
z.tr = append(z.tr, bs...)
}
}
func (z *ioDecReader) readn1eof() (b uint8, eof bool) {
b, err := z.br.ReadByte()
if err == nil {
z.n++
if z.trb {
z.tr = append(z.tr, b)
}
} else if err == io.EOF {
eof = true
} else {
panic(err)
}
return
}
func (z *ioDecReader) readn1() (b uint8) {
var err error
if b, err = z.br.ReadByte(); err == nil {
z.n++
if z.trb {
z.tr = append(z.tr, b)
}
return
}
panic(err)
}
func (z *ioDecReader) skip(accept *bitset256) (token byte) {
for {
var eof bool
token, eof = z.readn1eof()
if eof {
return
}
if accept.isset(token) {
continue
}
return
}
}
func (z *ioDecReader) readTo(in []byte, accept *bitset256) (out []byte) {
out = in
for {
token, eof := z.readn1eof()
if eof {
return
}
if accept.isset(token) {
out = append(out, token)
} else {
z.unreadn1()
return
}
}
}
func (z *ioDecReader) readUntil(in []byte, stop byte) (out []byte) {
out = in
for {
token, eof := z.readn1eof()
if eof {
panic(io.EOF)
}
out = append(out, token)
if token == stop {
return
}
}
}
func (z *ioDecReader) unreadn1() {
err := z.br.UnreadByte()
if err != nil {
panic(err)
}
z.n--
if z.trb {
if l := len(z.tr) - 1; l >= 0 {
z.tr = z.tr[:l]
}
}
}
func (z *ioDecReader) track() {
if z.tr != nil {
z.tr = z.tr[:0]
}
z.trb = true
}
func (z *ioDecReader) stopTrack() (bs []byte) {
z.trb = false
return z.tr
}
// ------------------------------------
var errBytesDecReaderCannotUnread = errors.New("cannot unread last byte read")
// bytesDecReader is a decReader that reads off a byte slice with zero copying
type bytesDecReader struct {
b []byte // data
c int // cursor
a int // available
t int // track start
}
func (z *bytesDecReader) reset(in []byte) {
z.b = in
z.a = len(in)
z.c = 0
z.t = 0
}
func (z *bytesDecReader) numread() int {
return z.c
}
func (z *bytesDecReader) unreadn1() {
if z.c == 0 || len(z.b) == 0 {
panic(errBytesDecReaderCannotUnread)
}
z.c--
z.a++
return
}
func (z *bytesDecReader) readx(n int) (bs []byte) {
// slicing from a non-constant start position is more expensive,
// as more computation is required to decipher the pointer start position.
// However, we do it only once, and it's better than reslicing both z.b and return value.
if n <= 0 {
} else if z.a == 0 {
panic(io.EOF)
} else if n > z.a {
panic(io.ErrUnexpectedEOF)
} else {
c0 := z.c
z.c = c0 + n
z.a = z.a - n
bs = z.b[c0:z.c]
}
return
}
func (z *bytesDecReader) readb(bs []byte) {
copy(bs, z.readx(len(bs)))
}
func (z *bytesDecReader) readn1() (v uint8) {
if z.a == 0 {
panic(io.EOF)
}
v = z.b[z.c]
z.c++
z.a--
return
}
// func (z *bytesDecReader) readn1eof() (v uint8, eof bool) {
// if z.a == 0 {
// eof = true
// return
// }
// v = z.b[z.c]
// z.c++
// z.a--
// return
// }
func (z *bytesDecReader) skip(accept *bitset256) (token byte) {
if z.a == 0 {
return
}
blen := len(z.b)
for i := z.c; i < blen; i++ {
if !accept.isset(z.b[i]) {
token = z.b[i]
i++
z.a -= (i - z.c)
z.c = i
return
}
}
z.a, z.c = 0, blen
return
}
func (z *bytesDecReader) readTo(_ []byte, accept *bitset256) (out []byte) {
if z.a == 0 {
return
}
blen := len(z.b)
for i := z.c; i < blen; i++ {
if !accept.isset(z.b[i]) {
out = z.b[z.c:i]
z.a -= (i - z.c)
z.c = i
return
}
}
out = z.b[z.c:]
z.a, z.c = 0, blen
return
}
func (z *bytesDecReader) readUntil(_ []byte, stop byte) (out []byte) {
if z.a == 0 {
panic(io.EOF)
}
blen := len(z.b)
for i := z.c; i < blen; i++ {
if z.b[i] == stop {
i++
out = z.b[z.c:i]
z.a -= (i - z.c)
z.c = i
return
}
}
z.a, z.c = 0, blen
panic(io.EOF)
}
func (z *bytesDecReader) track() {
z.t = z.c
}
func (z *bytesDecReader) stopTrack() (bs []byte) {
return z.b[z.t:z.c]
}
// ----------------------------------------
// func (d *Decoder) builtin(f *codecFnInfo, rv reflect.Value) {
// d.d.DecodeBuiltin(f.ti.rtid, rv2i(rv))
// }
func (d *Decoder) rawExt(f *codecFnInfo, rv reflect.Value) {
d.d.DecodeExt(rv2i(rv), 0, nil)
}
func (d *Decoder) ext(f *codecFnInfo, rv reflect.Value) {
d.d.DecodeExt(rv2i(rv), f.xfTag, f.xfFn)
}
func (d *Decoder) selferUnmarshal(f *codecFnInfo, rv reflect.Value) {
rv2i(rv).(Selfer).CodecDecodeSelf(d)
}
func (d *Decoder) binaryUnmarshal(f *codecFnInfo, rv reflect.Value) {
bm := rv2i(rv).(encoding.BinaryUnmarshaler)
xbs := d.d.DecodeBytes(nil, true)
if fnerr := bm.UnmarshalBinary(xbs); fnerr != nil {
panic(fnerr)
}
}
func (d *Decoder) textUnmarshal(f *codecFnInfo, rv reflect.Value) {
tm := rv2i(rv).(encoding.TextUnmarshaler)
fnerr := tm.UnmarshalText(d.d.DecodeStringAsBytes())
if fnerr != nil {
panic(fnerr)
}
}
func (d *Decoder) jsonUnmarshal(f *codecFnInfo, rv reflect.Value) {
tm := rv2i(rv).(jsonUnmarshaler)
// bs := d.d.DecodeBytes(d.b[:], true, true)
// grab the bytes to be read, as UnmarshalJSON needs the full JSON so as to unmarshal it itself.
fnerr := tm.UnmarshalJSON(d.nextValueBytes())
if fnerr != nil {
panic(fnerr)
}
}
func (d *Decoder) kErr(f *codecFnInfo, rv reflect.Value) {
d.errorf("no decoding function defined for kind %v", rv.Kind())
}
// var kIntfCtr uint64
func (d *Decoder) kInterfaceNaked(f *codecFnInfo) (rvn reflect.Value) {
// nil interface:
// use some hieristics to decode it appropriately
// based on the detected next value in the stream.
n := d.naked()
d.d.DecodeNaked()
if n.v == valueTypeNil {
return
}
// We cannot decode non-nil stream value into nil interface with methods (e.g. io.Reader).
if f.ti.numMeth > 0 {
d.errorf("cannot decode non-nil codec value into nil %v (%v methods)", f.ti.rt, f.ti.numMeth)
return
}
// var useRvn bool
switch n.v {
case valueTypeMap:
// if json, default to a map type with string keys
mtid := d.mtid
if mtid == 0 {
if d.jsms {
mtid = mapStrIntfTypId
} else {
mtid = mapIntfIntfTypId
}
}
if mtid == mapIntfIntfTypId {
n.initContainers()
if n.lm < arrayCacheLen {
n.ma[n.lm] = nil
rvn = n.rma[n.lm]
n.lm++
d.decode(&n.ma[n.lm-1])
n.lm--
} else {
var v2 map[interface{}]interface{}
d.decode(&v2)
rvn = reflect.ValueOf(&v2).Elem()
}
} else if mtid == mapStrIntfTypId { // for json performance
n.initContainers()
if n.ln < arrayCacheLen {
n.na[n.ln] = nil
rvn = n.rna[n.ln]
n.ln++
d.decode(&n.na[n.ln-1])
n.ln--
} else {
var v2 map[string]interface{}
d.decode(&v2)
rvn = reflect.ValueOf(&v2).Elem()
}
} else {
if d.mtr {
rvn = reflect.New(d.h.MapType)
d.decode(rv2i(rvn))
rvn = rvn.Elem()
} else {
rvn = reflect.New(d.h.MapType).Elem()
d.decodeValue(rvn, nil, true)
}
}
case valueTypeArray:
if d.stid == 0 || d.stid == intfSliceTypId {
n.initContainers()
if n.ls < arrayCacheLen {
n.sa[n.ls] = nil
rvn = n.rsa[n.ls]
n.ls++
d.decode(&n.sa[n.ls-1])
n.ls--
} else {
var v2 []interface{}
d.decode(&v2)
rvn = reflect.ValueOf(&v2).Elem()
}
if reflectArrayOfSupported && d.stid == 0 && d.h.PreferArrayOverSlice {
rvn2 := reflect.New(reflectArrayOf(rvn.Len(), intfTyp)).Elem()
reflect.Copy(rvn2, rvn)
rvn = rvn2
}
} else {
if d.str {
rvn = reflect.New(d.h.SliceType)
d.decode(rv2i(rvn))
rvn = rvn.Elem()
} else {
rvn = reflect.New(d.h.SliceType).Elem()
d.decodeValue(rvn, nil, true)
}
}
case valueTypeExt:
var v interface{}
tag, bytes := n.u, n.l // calling decode below might taint the values
if bytes == nil {
n.initContainers()
if n.li < arrayCacheLen {
n.ia[n.li] = nil
n.li++
d.decode(&n.ia[n.li-1])
// v = *(&n.ia[l])
n.li--
v = n.ia[n.li]
n.ia[n.li] = nil
} else {
d.decode(&v)
}
}
bfn := d.h.getExtForTag(tag)
if bfn == nil {
var re RawExt
re.Tag = tag
re.Data = detachZeroCopyBytes(d.bytes, nil, bytes)
re.Value = v
rvn = reflect.ValueOf(&re).Elem()
} else {
rvnA := reflect.New(bfn.rt)
if bytes != nil {
bfn.ext.ReadExt(rv2i(rvnA), bytes)
} else {
bfn.ext.UpdateExt(rv2i(rvnA), v)
}
rvn = rvnA.Elem()
}
case valueTypeNil:
// no-op
case valueTypeInt:
rvn = n.ri
case valueTypeUint:
rvn = n.ru
case valueTypeFloat:
rvn = n.rf
case valueTypeBool:
rvn = n.rb
case valueTypeString, valueTypeSymbol:
rvn = n.rs
case valueTypeBytes:
rvn = n.rl
case valueTypeTime:
rvn = n.rt
default:
panicv.errorf("kInterfaceNaked: unexpected valueType: %d", n.v)
}
return
}
func (d *Decoder) kInterface(f *codecFnInfo, rv reflect.Value) {
// Note:
// A consequence of how kInterface works, is that
// if an interface already contains something, we try
// to decode into what was there before.
// We do not replace with a generic value (as got from decodeNaked).
// every interface passed here MUST be settable.
var rvn reflect.Value
if rv.IsNil() || d.h.InterfaceReset {
// check if mapping to a type: if so, initialize it and move on
rvn = d.h.intf2impl(f.ti.rtid)
if rvn.IsValid() {
rv.Set(rvn)
} else {
rvn = d.kInterfaceNaked(f)
if rvn.IsValid() {
rv.Set(rvn)
} else if d.h.InterfaceReset {
// reset to zero value based on current type in there.
rv.Set(reflect.Zero(rv.Elem().Type()))
}
return
}
} else {
// now we have a non-nil interface value, meaning it contains a type
rvn = rv.Elem()
}
if d.d.TryDecodeAsNil() {
rv.Set(reflect.Zero(rvn.Type()))
return
}
// Note: interface{} is settable, but underlying type may not be.
// Consequently, we MAY have to create a decodable value out of the underlying value,
// decode into it, and reset the interface itself.
// fmt.Printf(">>>> kInterface: rvn type: %v, rv type: %v\n", rvn.Type(), rv.Type())
rvn2, canDecode := isDecodeable(rvn)
if canDecode {
d.decodeValue(rvn2, nil, true)
return
}
rvn2 = reflect.New(rvn.Type()).Elem()
rvn2.Set(rvn)
d.decodeValue(rvn2, nil, true)
rv.Set(rvn2)
}
func decStructFieldKey(dd decDriver, keyType valueType, b *[decScratchByteArrayLen]byte) (rvkencname []byte) {
// use if-else-if, not switch (which compiles to binary-search)
// since keyType is typically valueTypeString, branch prediction is pretty good.
if keyType == valueTypeString {
rvkencname = dd.DecodeStringAsBytes()
} else if keyType == valueTypeInt {
rvkencname = strconv.AppendInt(b[:0], dd.DecodeInt64(), 10)
} else if keyType == valueTypeUint {
rvkencname = strconv.AppendUint(b[:0], dd.DecodeUint64(), 10)
} else if keyType == valueTypeFloat {
rvkencname = strconv.AppendFloat(b[:0], dd.DecodeFloat64(), 'f', -1, 64)
} else {
rvkencname = dd.DecodeStringAsBytes()
}
return rvkencname
}
func (d *Decoder) kStruct(f *codecFnInfo, rv reflect.Value) {
fti := f.ti
dd := d.d
elemsep := d.esep
sfn := structFieldNode{v: rv, update: true}
ctyp := dd.ContainerType()
if ctyp == valueTypeMap {
containerLen := dd.ReadMapStart()
if containerLen == 0 {
dd.ReadMapEnd()
return
}
tisfi := fti.sfiSort
hasLen := containerLen >= 0
var rvkencname []byte
for j := 0; (hasLen && j < containerLen) || !(hasLen || dd.CheckBreak()); j++ {
if elemsep {
dd.ReadMapElemKey()
}
rvkencname = decStructFieldKey(dd, fti.keyType, &d.b)
if elemsep {
dd.ReadMapElemValue()
}
if k := fti.indexForEncName(rvkencname); k > -1 {
si := tisfi[k]
if dd.TryDecodeAsNil() {
si.setToZeroValue(rv)
} else {
d.decodeValue(sfn.field(si), nil, true)
}
} else {
d.structFieldNotFound(-1, stringView(rvkencname))
}
// keepAlive4StringView(rvkencnameB) // not needed, as reference is outside loop
}
dd.ReadMapEnd()
} else if ctyp == valueTypeArray {
containerLen := dd.ReadArrayStart()
if containerLen == 0 {
dd.ReadArrayEnd()
return
}
// Not much gain from doing it two ways for array.
// Arrays are not used as much for structs.
hasLen := containerLen >= 0
for j, si := range fti.sfiSrc {
if (hasLen && j == containerLen) || (!hasLen && dd.CheckBreak()) {
break
}
if elemsep {
dd.ReadArrayElem()
}
if dd.TryDecodeAsNil() {
si.setToZeroValue(rv)
} else {
d.decodeValue(sfn.field(si), nil, true)
}
}
if containerLen > len(fti.sfiSrc) {
// read remaining values and throw away
for j := len(fti.sfiSrc); j < containerLen; j++ {
if elemsep {
dd.ReadArrayElem()
}
d.structFieldNotFound(j, "")
}
}
dd.ReadArrayEnd()
} else {
d.errorstr(errstrOnlyMapOrArrayCanDecodeIntoStruct)
return
}
}
func (d *Decoder) kSlice(f *codecFnInfo, rv reflect.Value) {
// A slice can be set from a map or array in stream.
// This way, the order can be kept (as order is lost with map).
ti := f.ti
if f.seq == seqTypeChan && ti.chandir&uint8(reflect.SendDir) == 0 {
d.errorf("receive-only channel cannot be decoded")
}
dd := d.d
rtelem0 := ti.elem
ctyp := dd.ContainerType()
if ctyp == valueTypeBytes || ctyp == valueTypeString {
// you can only decode bytes or string in the stream into a slice or array of bytes
if !(ti.rtid == uint8SliceTypId || rtelem0.Kind() == reflect.Uint8) {
d.errorf("bytes/string in stream must decode into slice/array of bytes, not %v", ti.rt)
}
if f.seq == seqTypeChan {
bs2 := dd.DecodeBytes(nil, true)
irv := rv2i(rv)
ch, ok := irv.(chan<- byte)
if !ok {
ch = irv.(chan byte)
}
for _, b := range bs2 {
ch <- b
}
} else {
rvbs := rv.Bytes()
bs2 := dd.DecodeBytes(rvbs, false)
// if rvbs == nil && bs2 != nil || rvbs != nil && bs2 == nil || len(bs2) != len(rvbs) {
if !(len(bs2) > 0 && len(bs2) == len(rvbs) && &bs2[0] == &rvbs[0]) {
if rv.CanSet() {
rv.SetBytes(bs2)
} else if len(rvbs) > 0 && len(bs2) > 0 {
copy(rvbs, bs2)
}
}
}
return
}
// array := f.seq == seqTypeChan
slh, containerLenS := d.decSliceHelperStart() // only expects valueType(Array|Map)
// an array can never return a nil slice. so no need to check f.array here.
if containerLenS == 0 {
if rv.CanSet() {
if f.seq == seqTypeSlice {
if rv.IsNil() {
rv.Set(reflect.MakeSlice(ti.rt, 0, 0))
} else {
rv.SetLen(0)
}
} else if f.seq == seqTypeChan {
if rv.IsNil() {
rv.Set(reflect.MakeChan(ti.rt, 0))
}
}
}
slh.End()
return
}
rtelem0Size := int(rtelem0.Size())
rtElem0Kind := rtelem0.Kind()
rtelem0Mut := !isImmutableKind(rtElem0Kind)
rtelem := rtelem0
rtelemkind := rtelem.Kind()
for rtelemkind == reflect.Ptr {
rtelem = rtelem.Elem()
rtelemkind = rtelem.Kind()
}
var fn *codecFn
var rvCanset = rv.CanSet()
var rvChanged bool
var rv0 = rv
var rv9 reflect.Value
rvlen := rv.Len()
rvcap := rv.Cap()
hasLen := containerLenS > 0
if hasLen && f.seq == seqTypeSlice {
if containerLenS > rvcap {
oldRvlenGtZero := rvlen > 0
rvlen = decInferLen(containerLenS, d.h.MaxInitLen, int(rtelem0.Size()))
if rvlen <= rvcap {
if rvCanset {
rv.SetLen(rvlen)
}
} else if rvCanset {
rv = reflect.MakeSlice(ti.rt, rvlen, rvlen)
rvcap = rvlen
rvChanged = true
} else {
d.errorf("cannot decode into non-settable slice")
}
if rvChanged && oldRvlenGtZero && !isImmutableKind(rtelem0.Kind()) {
reflect.Copy(rv, rv0) // only copy up to length NOT cap i.e. rv0.Slice(0, rvcap)
}
} else if containerLenS != rvlen {
rvlen = containerLenS
if rvCanset {
rv.SetLen(rvlen)
}
// else {
// rv = rv.Slice(0, rvlen)
// rvChanged = true
// d.errorf("cannot decode into non-settable slice")
// }
}
}
// consider creating new element once, and just decoding into it.
var rtelem0Zero reflect.Value
var rtelem0ZeroValid bool
var decodeAsNil bool
var j int
d.cfer()
for ; (hasLen && j < containerLenS) || !(hasLen || dd.CheckBreak()); j++ {
if j == 0 && (f.seq == seqTypeSlice || f.seq == seqTypeChan) && rv.IsNil() {
if hasLen {
rvlen = decInferLen(containerLenS, d.h.MaxInitLen, rtelem0Size)
} else if f.seq == seqTypeSlice {
rvlen = decDefSliceCap
} else {
rvlen = decDefChanCap
}
if rvCanset {
if f.seq == seqTypeSlice {
rv = reflect.MakeSlice(ti.rt, rvlen, rvlen)
rvChanged = true
} else { // chan
// xdebugf(">>>>>> haslen = %v, make chan of type '%v' with length: %v", hasLen, ti.rt, rvlen)
rv = reflect.MakeChan(ti.rt, rvlen)
rvChanged = true
}
} else {
d.errorf("cannot decode into non-settable slice")
}
}
slh.ElemContainerState(j)
decodeAsNil = dd.TryDecodeAsNil()
if f.seq == seqTypeChan {
if decodeAsNil {
rv.Send(reflect.Zero(rtelem0))
continue
}
if rtelem0Mut || !rv9.IsValid() { // || (rtElem0Kind == reflect.Ptr && rv9.IsNil()) {
rv9 = reflect.New(rtelem0).Elem()
}
if fn == nil {
fn = d.cf.get(rtelem, true, true)
}
d.decodeValue(rv9, fn, true)
// xdebugf(">>>> rv9 sent on %v during decode: %v, with len=%v, cap=%v", rv.Type(), rv9, rv.Len(), rv.Cap())
rv.Send(rv9)
} else {
// if indefinite, etc, then expand the slice if necessary
var decodeIntoBlank bool
if j >= rvlen {
if f.seq == seqTypeArray {
d.arrayCannotExpand(rvlen, j+1)
decodeIntoBlank = true
} else { // if f.seq == seqTypeSlice
// rv = reflect.Append(rv, reflect.Zero(rtelem0)) // append logic + varargs
var rvcap2 int
var rvErrmsg2 string
rv9, rvcap2, rvChanged, rvErrmsg2 =
expandSliceRV(rv, ti.rt, rvCanset, rtelem0Size, 1, rvlen, rvcap)
if rvErrmsg2 != "" {
d.errorf(rvErrmsg2)
}
rvlen++
if rvChanged {
rv = rv9
rvcap = rvcap2
}
}
}
if decodeIntoBlank {
if !decodeAsNil {
d.swallow()
}
} else {
rv9 = rv.Index(j)
if d.h.SliceElementReset || decodeAsNil {
if !rtelem0ZeroValid {
rtelem0ZeroValid = true
rtelem0Zero = reflect.Zero(rtelem0)
}
rv9.Set(rtelem0Zero)
}
if decodeAsNil {
continue
}
if fn == nil {
fn = d.cf.get(rtelem, true, true)
}
d.decodeValue(rv9, fn, true)
}
}
}
if f.seq == seqTypeSlice {
if j < rvlen {
if rv.CanSet() {
rv.SetLen(j)
} else if rvCanset {
rv = rv.Slice(0, j)
rvChanged = true
} // else { d.errorf("kSlice: cannot change non-settable slice") }
rvlen = j
} else if j == 0 && rv.IsNil() {
if rvCanset {
rv = reflect.MakeSlice(ti.rt, 0, 0)
rvChanged = true
} // else { d.errorf("kSlice: cannot change non-settable slice") }
}
}
slh.End()
if rvChanged { // infers rvCanset=true, so it can be reset
rv0.Set(rv)
}
}
// func (d *Decoder) kArray(f *codecFnInfo, rv reflect.Value) {
// // d.decodeValueFn(rv.Slice(0, rv.Len()))
// f.kSlice(rv.Slice(0, rv.Len()))
// }
func (d *Decoder) kMap(f *codecFnInfo, rv reflect.Value) {
dd := d.d
containerLen := dd.ReadMapStart()
elemsep := d.esep
ti := f.ti
if rv.IsNil() {
rv.Set(makeMapReflect(ti.rt, containerLen))
}
if containerLen == 0 {
dd.ReadMapEnd()
return
}
ktype, vtype := ti.key, ti.elem
ktypeId := rt2id(ktype)
vtypeKind := vtype.Kind()
var keyFn, valFn *codecFn
var ktypeLo, vtypeLo reflect.Type
for ktypeLo = ktype; ktypeLo.Kind() == reflect.Ptr; ktypeLo = ktypeLo.Elem() {
}
for vtypeLo = vtype; vtypeLo.Kind() == reflect.Ptr; vtypeLo = vtypeLo.Elem() {
}
var mapGet, mapSet bool
rvvImmut := isImmutableKind(vtypeKind)
if !d.h.MapValueReset {
// if pointer, mapGet = true
// if interface, mapGet = true if !DecodeNakedAlways (else false)
// if builtin, mapGet = false
// else mapGet = true
if vtypeKind == reflect.Ptr {
mapGet = true
} else if vtypeKind == reflect.Interface {
if !d.h.InterfaceReset {
mapGet = true
}
} else if !rvvImmut {
mapGet = true
}
}
var rvk, rvkp, rvv, rvz reflect.Value
rvkMut := !isImmutableKind(ktype.Kind()) // if ktype is immutable, then re-use the same rvk.
ktypeIsString := ktypeId == stringTypId
ktypeIsIntf := ktypeId == intfTypId
hasLen := containerLen > 0
var kstrbs []byte
d.cfer()
for j := 0; (hasLen && j < containerLen) || !(hasLen || dd.CheckBreak()); j++ {
if rvkMut || !rvkp.IsValid() {
rvkp = reflect.New(ktype)
rvk = rvkp.Elem()
}
if elemsep {
dd.ReadMapElemKey()
}
if false && dd.TryDecodeAsNil() { // nil cannot be a map key, so disregard this block
// Previously, if a nil key, we just ignored the mapped value and continued.
// However, that makes the result of encoding and then decoding map[intf]intf{nil:nil}
// to be an empty map.
// Instead, we treat a nil key as the zero value of the type.
rvk.Set(reflect.Zero(ktype))
} else if ktypeIsString {
kstrbs = dd.DecodeStringAsBytes()
rvk.SetString(stringView(kstrbs))
// NOTE: if doing an insert, you MUST use a real string (not stringview)
} else {
if keyFn == nil {
keyFn = d.cf.get(ktypeLo, true, true)
}
d.decodeValue(rvk, keyFn, true)
}
// special case if a byte array.
if ktypeIsIntf {
if rvk2 := rvk.Elem(); rvk2.IsValid() {
if rvk2.Type() == uint8SliceTyp {
rvk = reflect.ValueOf(d.string(rvk2.Bytes()))
} else {
rvk = rvk2
}
}
}
if elemsep {
dd.ReadMapElemValue()
}
// Brittle, but OK per TryDecodeAsNil() contract.
// i.e. TryDecodeAsNil never shares slices with other decDriver procedures
if dd.TryDecodeAsNil() {
if ktypeIsString {
rvk.SetString(d.string(kstrbs))
}
if d.h.DeleteOnNilMapValue {
rv.SetMapIndex(rvk, reflect.Value{})
} else {
rv.SetMapIndex(rvk, reflect.Zero(vtype))
}
continue
}
mapSet = true // set to false if u do a get, and its a non-nil pointer
if mapGet {
// mapGet true only in case where kind=Ptr|Interface or kind is otherwise mutable.
rvv = rv.MapIndex(rvk)
if !rvv.IsValid() {
rvv = reflect.New(vtype).Elem()
} else if vtypeKind == reflect.Ptr {
if rvv.IsNil() {
rvv = reflect.New(vtype).Elem()
} else {
mapSet = false
}
} else if vtypeKind == reflect.Interface {
// not addressable, and thus not settable.
// e MUST create a settable/addressable variant
rvv2 := reflect.New(rvv.Type()).Elem()
if !rvv.IsNil() {
rvv2.Set(rvv)
}
rvv = rvv2
}
// else it is ~mutable, and we can just decode into it directly
} else if rvvImmut {
if !rvz.IsValid() {
rvz = reflect.New(vtype).Elem()
}
rvv = rvz
} else {
rvv = reflect.New(vtype).Elem()
}
// We MUST be done with the stringview of the key, before decoding the value
// so that we don't bastardize the reused byte array.
if mapSet && ktypeIsString {
rvk.SetString(d.string(kstrbs))
}
if valFn == nil {
valFn = d.cf.get(vtypeLo, true, true)
}
d.decodeValue(rvv, valFn, true)
// d.decodeValueFn(rvv, valFn)
if mapSet {
rv.SetMapIndex(rvk, rvv)
}
// if ktypeIsString {
// // keepAlive4StringView(kstrbs) // not needed, as reference is outside loop
// }
}
dd.ReadMapEnd()
}
// decNaked is used to keep track of the primitives decoded.
// Without it, we would have to decode each primitive and wrap it
// in an interface{}, causing an allocation.
// In this model, the primitives are decoded in a "pseudo-atomic" fashion,
// so we can rest assured that no other decoding happens while these
// primitives are being decoded.
//
// maps and arrays are not handled by this mechanism.
// However, RawExt is, and we accommodate for extensions that decode
// RawExt from DecodeNaked, but need to decode the value subsequently.
// kInterfaceNaked and swallow, which call DecodeNaked, handle this caveat.
//
// However, decNaked also keeps some arrays of default maps and slices
// used in DecodeNaked. This way, we can get a pointer to it
// without causing a new heap allocation.
//
// kInterfaceNaked will ensure that there is no allocation for the common
// uses.
type decNakedContainers struct {
// array/stacks for reducing allocation
// keep arrays at the bottom? Chance is that they are not used much.
ia [arrayCacheLen]interface{}
ma [arrayCacheLen]map[interface{}]interface{}
na [arrayCacheLen]map[string]interface{}
sa [arrayCacheLen][]interface{}
// ria [arrayCacheLen]reflect.Value // not needed, as we decode directly into &ia[n]
rma, rna, rsa [arrayCacheLen]reflect.Value // reflect.Value mapping to above
}
func (n *decNakedContainers) init() {
for i := 0; i < arrayCacheLen; i++ {
// n.ria[i] = reflect.ValueOf(&(n.ia[i])).Elem()
n.rma[i] = reflect.ValueOf(&(n.ma[i])).Elem()
n.rna[i] = reflect.ValueOf(&(n.na[i])).Elem()
n.rsa[i] = reflect.ValueOf(&(n.sa[i])).Elem()
}
}
type decNaked struct {
// r RawExt // used for RawExt, uint, []byte.
// primitives below
u uint64
i int64
f float64
l []byte
s string
// ---- cpu cache line boundary?
t time.Time
b bool
// state
v valueType
li, lm, ln, ls int8
inited bool
*decNakedContainers
ru, ri, rf, rl, rs, rb, rt reflect.Value // mapping to the primitives above
// _ [6]uint64 // padding // no padding - rt goes into next cache line
}
func (n *decNaked) init() {
if n.inited {
return
}
n.ru = reflect.ValueOf(&n.u).Elem()
n.ri = reflect.ValueOf(&n.i).Elem()
n.rf = reflect.ValueOf(&n.f).Elem()
n.rl = reflect.ValueOf(&n.l).Elem()
n.rs = reflect.ValueOf(&n.s).Elem()
n.rt = reflect.ValueOf(&n.t).Elem()
n.rb = reflect.ValueOf(&n.b).Elem()
n.inited = true
// n.rr[] = reflect.ValueOf(&n.)
}
func (n *decNaked) initContainers() {
if n.decNakedContainers == nil {
n.decNakedContainers = new(decNakedContainers)
n.decNakedContainers.init()
}
}
func (n *decNaked) reset() {
if n == nil {
return
}
n.li, n.lm, n.ln, n.ls = 0, 0, 0, 0
}
type rtid2rv struct {
rtid uintptr
rv reflect.Value
}
// --------------
type decReaderSwitch struct {
rb bytesDecReader
// ---- cpu cache line boundary?
ri *ioDecReader
mtr, str bool // whether maptype or slicetype are known types
be bool // is binary encoding
bytes bool // is bytes reader
js bool // is json handle
jsms bool // is json handle, and MapKeyAsString
esep bool // has elem separators
}
// TODO: Uncomment after mid-stack inlining enabled in go 1.11
//
// func (z *decReaderSwitch) unreadn1() {
// if z.bytes {
// z.rb.unreadn1()
// } else {
// z.ri.unreadn1()
// }
// }
// func (z *decReaderSwitch) readx(n int) []byte {
// if z.bytes {
// return z.rb.readx(n)
// }
// return z.ri.readx(n)
// }
// func (z *decReaderSwitch) readb(s []byte) {
// if z.bytes {
// z.rb.readb(s)
// } else {
// z.ri.readb(s)
// }
// }
// func (z *decReaderSwitch) readn1() uint8 {
// if z.bytes {
// return z.rb.readn1()
// }
// return z.ri.readn1()
// }
// func (z *decReaderSwitch) numread() int {
// if z.bytes {
// return z.rb.numread()
// }
// return z.ri.numread()
// }
// func (z *decReaderSwitch) track() {
// if z.bytes {
// z.rb.track()
// } else {
// z.ri.track()
// }
// }
// func (z *decReaderSwitch) stopTrack() []byte {
// if z.bytes {
// return z.rb.stopTrack()
// }
// return z.ri.stopTrack()
// }
// func (z *decReaderSwitch) skip(accept *bitset256) (token byte) {
// if z.bytes {
// return z.rb.skip(accept)
// }
// return z.ri.skip(accept)
// }
// func (z *decReaderSwitch) readTo(in []byte, accept *bitset256) (out []byte) {
// if z.bytes {
// return z.rb.readTo(in, accept)
// }
// return z.ri.readTo(in, accept)
// }
// func (z *decReaderSwitch) readUntil(in []byte, stop byte) (out []byte) {
// if z.bytes {
// return z.rb.readUntil(in, stop)
// }
// return z.ri.readUntil(in, stop)
// }
// A Decoder reads and decodes an object from an input stream in the codec format.
type Decoder struct {
panicHdl
// hopefully, reduce derefencing cost by laying the decReader inside the Decoder.
// Try to put things that go together to fit within a cache line (8 words).
d decDriver
// NOTE: Decoder shouldn't call it's read methods,
// as the handler MAY need to do some coordination.
r decReader
h *BasicHandle
bi *bufioDecReader
// cache the mapTypeId and sliceTypeId for faster comparisons
mtid uintptr
stid uintptr
// ---- cpu cache line boundary?
decReaderSwitch
// ---- cpu cache line boundary?
codecFnPooler
// cr containerStateRecv
n *decNaked
nsp *sync.Pool
err error
// ---- cpu cache line boundary?
b [decScratchByteArrayLen]byte // scratch buffer, used by Decoder and xxxEncDrivers
is map[string]string // used for interning strings
// padding - false sharing help // modify 232 if Decoder struct changes.
// _ [cacheLineSize - 232%cacheLineSize]byte
}
// NewDecoder returns a Decoder for decoding a stream of bytes from an io.Reader.
//
// For efficiency, Users are encouraged to pass in a memory buffered reader
// (eg bufio.Reader, bytes.Buffer).
func NewDecoder(r io.Reader, h Handle) *Decoder {
d := newDecoder(h)
d.Reset(r)
return d
}
// NewDecoderBytes returns a Decoder which efficiently decodes directly
// from a byte slice with zero copying.
func NewDecoderBytes(in []byte, h Handle) *Decoder {
d := newDecoder(h)
d.ResetBytes(in)
return d
}
var defaultDecNaked decNaked
func newDecoder(h Handle) *Decoder {
d := &Decoder{h: h.getBasicHandle(), err: errDecoderNotInitialized}
d.hh = h
d.be = h.isBinary()
// NOTE: do not initialize d.n here. It is lazily initialized in d.naked()
var jh *JsonHandle
jh, d.js = h.(*JsonHandle)
if d.js {
d.jsms = jh.MapKeyAsString
}
d.esep = d.hh.hasElemSeparators()
if d.h.InternString {
d.is = make(map[string]string, 32)
}
d.d = h.newDecDriver(d)
// d.cr, _ = d.d.(containerStateRecv)
return d
}
func (d *Decoder) resetCommon() {
d.n.reset()
d.d.reset()
d.err = nil
// reset all things which were cached from the Handle, but could change
d.mtid, d.stid = 0, 0
d.mtr, d.str = false, false
if d.h.MapType != nil {
d.mtid = rt2id(d.h.MapType)
d.mtr = fastpathAV.index(d.mtid) != -1
}
if d.h.SliceType != nil {
d.stid = rt2id(d.h.SliceType)
d.str = fastpathAV.index(d.stid) != -1
}
}
// Reset the Decoder with a new Reader to decode from,
// clearing all state from last run(s).
func (d *Decoder) Reset(r io.Reader) {
if r == nil {
return
}
if d.bi == nil {
d.bi = new(bufioDecReader)
}
d.bytes = false
if d.h.ReaderBufferSize > 0 {
d.bi.buf = make([]byte, 0, d.h.ReaderBufferSize)
d.bi.reset(r)
d.r = d.bi
} else {
// d.ri.x = &d.b
// d.s = d.sa[:0]
if d.ri == nil {
d.ri = new(ioDecReader)
}
d.ri.reset(r)
d.r = d.ri
}
d.resetCommon()
}
// ResetBytes resets the Decoder with a new []byte to decode from,
// clearing all state from last run(s).
func (d *Decoder) ResetBytes(in []byte) {
if in == nil {
return
}
d.bytes = true
d.rb.reset(in)
d.r = &d.rb
d.resetCommon()
}
// naked must be called before each call to .DecodeNaked,
// as they will use it.
func (d *Decoder) naked() *decNaked {
if d.n == nil {
// consider one of:
// - get from sync.Pool (if GC is frequent, there's no value here)
// - new alloc (safest. only init'ed if it a naked decode will be done)
// - field in Decoder (makes the Decoder struct very big)
// To support using a decoder where a DecodeNaked is not needed,
// we prefer #1 or #2.
// d.n = new(decNaked) // &d.nv // new(decNaked) // grab from a sync.Pool
// d.n.init()
var v interface{}
d.nsp, v = pool.decNaked()
d.n = v.(*decNaked)
}
return d.n
}
// Decode decodes the stream from reader and stores the result in the
// value pointed to by v. v cannot be a nil pointer. v can also be
// a reflect.Value of a pointer.
//
// Note that a pointer to a nil interface is not a nil pointer.
// If you do not know what type of stream it is, pass in a pointer to a nil interface.
// We will decode and store a value in that nil interface.
//
// Sample usages:
// // Decoding into a non-nil typed value
// var f float32
// err = codec.NewDecoder(r, handle).Decode(&f)
//
// // Decoding into nil interface
// var v interface{}
// dec := codec.NewDecoder(r, handle)
// err = dec.Decode(&v)
//
// When decoding into a nil interface{}, we will decode into an appropriate value based
// on the contents of the stream:
// - Numbers are decoded as float64, int64 or uint64.
// - Other values are decoded appropriately depending on the type:
// bool, string, []byte, time.Time, etc
// - Extensions are decoded as RawExt (if no ext function registered for the tag)
// Configurations exist on the Handle to override defaults
// (e.g. for MapType, SliceType and how to decode raw bytes).
//
// When decoding into a non-nil interface{} value, the mode of encoding is based on the
// type of the value. When a value is seen:
// - If an extension is registered for it, call that extension function
// - If it implements BinaryUnmarshaler, call its UnmarshalBinary(data []byte) error
// - Else decode it based on its reflect.Kind
//
// There are some special rules when decoding into containers (slice/array/map/struct).
// Decode will typically use the stream contents to UPDATE the container.
// - A map can be decoded from a stream map, by updating matching keys.
// - A slice can be decoded from a stream array,
// by updating the first n elements, where n is length of the stream.
// - A slice can be decoded from a stream map, by decoding as if
// it contains a sequence of key-value pairs.
// - A struct can be decoded from a stream map, by updating matching fields.
// - A struct can be decoded from a stream array,
// by updating fields as they occur in the struct (by index).
//
// When decoding a stream map or array with length of 0 into a nil map or slice,
// we reset the destination map or slice to a zero-length value.
//
// However, when decoding a stream nil, we reset the destination container
// to its "zero" value (e.g. nil for slice/map, etc).
//
// Note: we allow nil values in the stream anywhere except for map keys.
// A nil value in the encoded stream where a map key is expected is treated as an error.
func (d *Decoder) Decode(v interface{}) (err error) {
defer d.deferred(&err)
d.MustDecode(v)
return
}
// MustDecode is like Decode, but panics if unable to Decode.
// This provides insight to the code location that triggered the error.
func (d *Decoder) MustDecode(v interface{}) {
// TODO: Top-level: ensure that v is a pointer and not nil.
if d.err != nil {
panic(d.err)
}
if d.d.TryDecodeAsNil() {
setZero(v)
} else {
d.decode(v)
}
d.alwaysAtEnd()
// xprintf(">>>>>>>> >>>>>>>> num decFns: %v\n", d.cf.sn)
}
func (d *Decoder) deferred(err1 *error) {
d.alwaysAtEnd()
if recoverPanicToErr {
if x := recover(); x != nil {
panicValToErr(d, x, err1)
panicValToErr(d, x, &d.err)
}
}
}
func (d *Decoder) alwaysAtEnd() {
if d.n != nil {
// if n != nil, then nsp != nil (they are always set together)
d.nsp.Put(d.n)
d.n, d.nsp = nil, nil
}
d.codecFnPooler.alwaysAtEnd()
}
// // this is not a smart swallow, as it allocates objects and does unnecessary work.
// func (d *Decoder) swallowViaHammer() {
// var blank interface{}
// d.decodeValueNoFn(reflect.ValueOf(&blank).Elem())
// }
func (d *Decoder) swallow() {
// smarter decode that just swallows the content
dd := d.d
if dd.TryDecodeAsNil() {
return
}
elemsep := d.esep
switch dd.ContainerType() {
case valueTypeMap:
containerLen := dd.ReadMapStart()
hasLen := containerLen >= 0
for j := 0; (hasLen && j < containerLen) || !(hasLen || dd.CheckBreak()); j++ {
// if clenGtEqualZero {if j >= containerLen {break} } else if dd.CheckBreak() {break}
if elemsep {
dd.ReadMapElemKey()
}
d.swallow()
if elemsep {
dd.ReadMapElemValue()
}
d.swallow()
}
dd.ReadMapEnd()
case valueTypeArray:
containerLen := dd.ReadArrayStart()
hasLen := containerLen >= 0
for j := 0; (hasLen && j < containerLen) || !(hasLen || dd.CheckBreak()); j++ {
if elemsep {
dd.ReadArrayElem()
}
d.swallow()
}
dd.ReadArrayEnd()
case valueTypeBytes:
dd.DecodeBytes(d.b[:], true)
case valueTypeString:
dd.DecodeStringAsBytes()
default:
// these are all primitives, which we can get from decodeNaked
// if RawExt using Value, complete the processing.
n := d.naked()
dd.DecodeNaked()
if n.v == valueTypeExt && n.l == nil {
n.initContainers()
if n.li < arrayCacheLen {
n.ia[n.li] = nil
n.li++
d.decode(&n.ia[n.li-1])
n.ia[n.li-1] = nil
n.li--
} else {
var v2 interface{}
d.decode(&v2)
}
}
}
}
func setZero(iv interface{}) {
if iv == nil || definitelyNil(iv) {
return
}
var canDecode bool
switch v := iv.(type) {
case *string:
*v = ""
case *bool:
*v = false
case *int:
*v = 0
case *int8:
*v = 0
case *int16:
*v = 0
case *int32:
*v = 0
case *int64:
*v = 0
case *uint:
*v = 0
case *uint8:
*v = 0
case *uint16:
*v = 0
case *uint32:
*v = 0
case *uint64:
*v = 0
case *float32:
*v = 0
case *float64:
*v = 0
case *[]uint8:
*v = nil
case *Raw:
*v = nil
case *time.Time:
*v = time.Time{}
case reflect.Value:
if v, canDecode = isDecodeable(v); canDecode && v.CanSet() {
v.Set(reflect.Zero(v.Type()))
} // TODO: else drain if chan, clear if map, set all to nil if slice???
default:
if !fastpathDecodeSetZeroTypeSwitch(iv) {
v := reflect.ValueOf(iv)
if v, canDecode = isDecodeable(v); canDecode && v.CanSet() {
v.Set(reflect.Zero(v.Type()))
} // TODO: else drain if chan, clear if map, set all to nil if slice???
}
}
}
func (d *Decoder) decode(iv interface{}) {
// check nil and interfaces explicitly,
// so that type switches just have a run of constant non-interface types.
if iv == nil {
d.errorstr(errstrCannotDecodeIntoNil)
return
}
if v, ok := iv.(Selfer); ok {
v.CodecDecodeSelf(d)
return
}
switch v := iv.(type) {
// case nil:
// case Selfer:
case reflect.Value:
v = d.ensureDecodeable(v)
d.decodeValue(v, nil, true)
case *string:
*v = d.d.DecodeString()
case *bool:
*v = d.d.DecodeBool()
case *int:
*v = int(chkOvf.IntV(d.d.DecodeInt64(), intBitsize))
case *int8:
*v = int8(chkOvf.IntV(d.d.DecodeInt64(), 8))
case *int16:
*v = int16(chkOvf.IntV(d.d.DecodeInt64(), 16))
case *int32:
*v = int32(chkOvf.IntV(d.d.DecodeInt64(), 32))
case *int64:
*v = d.d.DecodeInt64()
case *uint:
*v = uint(chkOvf.UintV(d.d.DecodeUint64(), uintBitsize))
case *uint8:
*v = uint8(chkOvf.UintV(d.d.DecodeUint64(), 8))
case *uint16:
*v = uint16(chkOvf.UintV(d.d.DecodeUint64(), 16))
case *uint32:
*v = uint32(chkOvf.UintV(d.d.DecodeUint64(), 32))
case *uint64:
*v = d.d.DecodeUint64()
case *float32:
f64 := d.d.DecodeFloat64()
if chkOvf.Float32(f64) {
d.errorf("float32 overflow: %v", f64)
}
*v = float32(f64)
case *float64:
*v = d.d.DecodeFloat64()
case *[]uint8:
*v = d.d.DecodeBytes(*v, false)
case []uint8:
b := d.d.DecodeBytes(v, false)
if !(len(b) > 0 && len(b) == len(v) && &b[0] == &v[0]) {
copy(v, b)
}
case *time.Time:
*v = d.d.DecodeTime()
case *Raw:
*v = d.rawBytes()
case *interface{}:
d.decodeValue(reflect.ValueOf(iv).Elem(), nil, true)
// d.decodeValueNotNil(reflect.ValueOf(iv).Elem())
default:
if !fastpathDecodeTypeSwitch(iv, d) {
v := reflect.ValueOf(iv)
v = d.ensureDecodeable(v)
d.decodeValue(v, nil, false)
// d.decodeValueFallback(v)
}
}
}
func (d *Decoder) decodeValue(rv reflect.Value, fn *codecFn, chkAll bool) {
// If stream is not containing a nil value, then we can deref to the base
// non-pointer value, and decode into that.
var rvp reflect.Value
var rvpValid bool
if rv.Kind() == reflect.Ptr {
rvpValid = true
for {
if rv.IsNil() {
rv.Set(reflect.New(rv.Type().Elem()))
}
rvp = rv
rv = rv.Elem()
if rv.Kind() != reflect.Ptr {
break
}
}
}
if fn == nil {
// always pass checkCodecSelfer=true, in case T or ****T is passed, where *T is a Selfer
fn = d.cfer().get(rv.Type(), chkAll, true) // chkAll, chkAll)
}
if fn.i.addrD {
if rvpValid {
fn.fd(d, &fn.i, rvp)
} else if rv.CanAddr() {
fn.fd(d, &fn.i, rv.Addr())
} else if !fn.i.addrF {
fn.fd(d, &fn.i, rv)
} else {
d.errorf("cannot decode into a non-pointer value")
}
} else {
fn.fd(d, &fn.i, rv)
}
// return rv
}
func (d *Decoder) structFieldNotFound(index int, rvkencname string) {
// NOTE: rvkencname may be a stringView, so don't pass it to another function.
if d.h.ErrorIfNoField {
if index >= 0 {
d.errorf("no matching struct field found when decoding stream array at index %v", index)
return
} else if rvkencname != "" {
d.errorf("no matching struct field found when decoding stream map with key " + rvkencname)
return
}
}
d.swallow()
}
func (d *Decoder) arrayCannotExpand(sliceLen, streamLen int) {
if d.h.ErrorIfNoArrayExpand {
d.errorf("cannot expand array len during decode from %v to %v", sliceLen, streamLen)
}
}
func isDecodeable(rv reflect.Value) (rv2 reflect.Value, canDecode bool) {
switch rv.Kind() {
case reflect.Array:
return rv, true
case reflect.Ptr:
if !rv.IsNil() {
return rv.Elem(), true
}
case reflect.Slice, reflect.Chan, reflect.Map:
if !rv.IsNil() {
return rv, true
}
}
return
}
func (d *Decoder) ensureDecodeable(rv reflect.Value) (rv2 reflect.Value) {
// decode can take any reflect.Value that is a inherently addressable i.e.
// - array
// - non-nil chan (we will SEND to it)
// - non-nil slice (we will set its elements)
// - non-nil map (we will put into it)
// - non-nil pointer (we can "update" it)
rv2, canDecode := isDecodeable(rv)
if canDecode {
return
}
if !rv.IsValid() {
d.errorstr(errstrCannotDecodeIntoNil)
return
}
if !rv.CanInterface() {
d.errorf("cannot decode into a value without an interface: %v", rv)
return
}
rvi := rv2i(rv)
rvk := rv.Kind()
d.errorf("cannot decode into value of kind: %v, type: %T, %v", rvk, rvi, rvi)
return
}
// Possibly get an interned version of a string
//
// This should mostly be used for map keys, where the key type is string.
// This is because keys of a map/struct are typically reused across many objects.
func (d *Decoder) string(v []byte) (s string) {
if d.is == nil {
return string(v) // don't return stringView, as we need a real string here.
}
s, ok := d.is[string(v)] // no allocation here, per go implementation
if !ok {
s = string(v) // new allocation here
d.is[s] = s
}
return s
}
// nextValueBytes returns the next value in the stream as a set of bytes.
func (d *Decoder) nextValueBytes() (bs []byte) {
d.d.uncacheRead()
d.r.track()
d.swallow()
bs = d.r.stopTrack()
return
}
func (d *Decoder) rawBytes() []byte {
// ensure that this is not a view into the bytes
// i.e. make new copy always.
bs := d.nextValueBytes()
bs2 := make([]byte, len(bs))
copy(bs2, bs)
return bs2
}
func (d *Decoder) wrapErrstr(v interface{}, err *error) {
*err = fmt.Errorf("%s decode error [pos %d]: %v", d.hh.Name(), d.r.numread(), v)
}
func (d *Decoder) NumBytesRead() int {
return d.r.numread()
}
// --------------------------------------------------
// decSliceHelper assists when decoding into a slice, from a map or an array in the stream.
// A slice can be set from a map or array in stream. This supports the MapBySlice interface.
type decSliceHelper struct {
d *Decoder
// ct valueType
array bool
}
func (d *Decoder) decSliceHelperStart() (x decSliceHelper, clen int) {
dd := d.d
ctyp := dd.ContainerType()
switch ctyp {
case valueTypeArray:
x.array = true
clen = dd.ReadArrayStart()
case valueTypeMap:
clen = dd.ReadMapStart() * 2
default:
d.errorf("only encoded map or array can be decoded into a slice (%d)", ctyp)
}
// x.ct = ctyp
x.d = d
return
}
func (x decSliceHelper) End() {
if x.array {
x.d.d.ReadArrayEnd()
} else {
x.d.d.ReadMapEnd()
}
}
func (x decSliceHelper) ElemContainerState(index int) {
if x.array {
x.d.d.ReadArrayElem()
} else if index%2 == 0 {
x.d.d.ReadMapElemKey()
} else {
x.d.d.ReadMapElemValue()
}
}
func decByteSlice(r decReader, clen, maxInitLen int, bs []byte) (bsOut []byte) {
if clen == 0 {
return zeroByteSlice
}
if len(bs) == clen {
bsOut = bs
r.readb(bsOut)
} else if cap(bs) >= clen {
bsOut = bs[:clen]
r.readb(bsOut)
} else {
// bsOut = make([]byte, clen)
len2 := decInferLen(clen, maxInitLen, 1)
bsOut = make([]byte, len2)
r.readb(bsOut)
for len2 < clen {
len3 := decInferLen(clen-len2, maxInitLen, 1)
bs3 := bsOut
bsOut = make([]byte, len2+len3)
copy(bsOut, bs3)
r.readb(bsOut[len2:])
len2 += len3
}
}
return
}
func detachZeroCopyBytes(isBytesReader bool, dest []byte, in []byte) (out []byte) {
if xlen := len(in); xlen > 0 {
if isBytesReader || xlen <= scratchByteArrayLen {
if cap(dest) >= xlen {
out = dest[:xlen]
} else {
out = make([]byte, xlen)
}
copy(out, in)
return
}
}
return in
}
// decInferLen will infer a sensible length, given the following:
// - clen: length wanted.
// - maxlen: max length to be returned.
// if <= 0, it is unset, and we infer it based on the unit size
// - unit: number of bytes for each element of the collection
func decInferLen(clen, maxlen, unit int) (rvlen int) {
// handle when maxlen is not set i.e. <= 0
if clen <= 0 {
return
}
if unit == 0 {
return clen
}
if maxlen <= 0 {
// no maxlen defined. Use maximum of 256K memory, with a floor of 4K items.
// maxlen = 256 * 1024 / unit
// if maxlen < (4 * 1024) {
// maxlen = 4 * 1024
// }
if unit < (256 / 4) {
maxlen = 256 * 1024 / unit
} else {
maxlen = 4 * 1024
}
}
if clen > maxlen {
rvlen = maxlen
} else {
rvlen = clen
}
return
}
func expandSliceRV(s reflect.Value, st reflect.Type, canChange bool, stElemSize, num, slen, scap int) (
s2 reflect.Value, scap2 int, changed bool, err string) {
l1 := slen + num // new slice length
if l1 < slen {
err = errmsgExpandSliceOverflow
return
}
if l1 <= scap {
if s.CanSet() {
s.SetLen(l1)
} else if canChange {
s2 = s.Slice(0, l1)
scap2 = scap
changed = true
} else {
err = errmsgExpandSliceCannotChange
return
}
return
}
if !canChange {
err = errmsgExpandSliceCannotChange
return
}
scap2 = growCap(scap, stElemSize, num)
s2 = reflect.MakeSlice(st, l1, scap2)
changed = true
reflect.Copy(s2, s)
return
}
func decReadFull(r io.Reader, bs []byte) (n int, err error) {
var nn int
for n < len(bs) && err == nil {
nn, err = r.Read(bs[n:])
if nn > 0 {
if err == io.EOF {
// leave EOF for next time
err = nil
}
n += nn
}
}
// do not do this - it serves no purpose
// if n != len(bs) && err == io.EOF { err = io.ErrUnexpectedEOF }
return
}