// 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 decodeError struct { codecError pos int } func (d decodeError) Error() string { return fmt.Sprintf("%s decode error [pos %d]: %v", d.name, d.pos, d.err) } 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() var mf MissingFielder if fti.mf { mf = rv2i(rv).(MissingFielder) } else if fti.mfp { mf = rv2i(rv.Addr()).(MissingFielder) } 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 if mf != nil { var f interface{} d.decode(&f) if !mf.CodecMissingField(rvkencname, f) && d.h.ErrorIfNoField { d.errorf("no matching struct field found when decoding stream map with key " + stringView(rvkencname)) } } 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 var checkbreak bool for j, si := range fti.sfiSrc { if hasLen && j == containerLen { break } if !hasLen && dd.CheckBreak() { checkbreak = true break } if elemsep { dd.ReadArrayElem() } if dd.TryDecodeAsNil() { si.setToZeroValue(rv) } else { d.decodeValue(sfn.field(si), nil, true) } } if (hasLen && containerLen > len(fti.sfiSrc)) || (!hasLen && !checkbreak) { // read remaining values and throw away for j := len(fti.sfiSrc); ; j++ { if (hasLen && j == containerLen) || (!hasLen && dd.CheckBreak()) { break } 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 bi *bufioDecReader 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 bufio bool // is this a bufioDecReader? } /* func (z *decReaderSwitch) unreadn1() { if z.bytes { z.rb.unreadn1() } else if z.bufio { z.bi.unreadn1() } else { z.ri.unreadn1() } } func (z *decReaderSwitch) readx(n int) []byte { if z.bytes { return z.rb.readx(n) } else if z.bufio { return z.bi.readx(n) } return z.ri.readx(n) } func (z *decReaderSwitch) readb(s []byte) { if z.bytes { z.rb.readb(s) } else if z.bufio { z.bi.readb(s) } else { z.ri.readb(s) } } func (z *decReaderSwitch) readn1() uint8 { if z.bytes { return z.rb.readn1() } else if z.bufio { return z.bi.readn1() } return z.ri.readn1() } func (z *decReaderSwitch) numread() int { if z.bytes { return z.rb.numread() } else if z.bufio { return z.bi.numread() } return z.ri.numread() } func (z *decReaderSwitch) track() { if z.bytes { z.rb.track() } else if z.bufio { z.bi.track() } else { z.ri.track() } } func (z *decReaderSwitch) stopTrack() []byte { if z.bytes { return z.rb.stopTrack() } else if z.bufio { return z.bi.stopTrack() } return z.ri.stopTrack() } func (z *decReaderSwitch) skip(accept *bitset256) (token byte) { if z.bytes { return z.rb.skip(accept) } else if z.bufio { return z.bi.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) } else if z.bufio { return z.bi.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) } else if z.bufio { return z.bi.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 // bi *bufioDecReader // cache the mapTypeId and sliceTypeId for faster comparisons mtid uintptr stid uintptr n *decNaked nsp *sync.Pool // ---- cpu cache line boundary? decReaderSwitch // ---- cpu cache line boundary? codecFnPooler // cr containerStateRecv err error h *BasicHandle _ [1]uint64 // padding // ---- 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.r = &d.decReaderSwitch 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 } d.bytes = false if d.h.ReaderBufferSize > 0 { if d.bi == nil { d.bi = new(bufioDecReader) } if cap(d.bi.buf) < d.h.ReaderBufferSize { d.bi.buf = make([]byte, 0, d.h.ReaderBufferSize) } else { d.bi.buf = d.bi.buf[:0] } d.bi.reset(r) d.r = d.bi d.bufio = true } 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.bufio = false } 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) wrapErr(v interface{}, err *error) { *err = decodeError{codecError: codecError{name: d.hh.Name(), err: v}, pos: d.r.numread()} } // NumBytesRead returns the number of bytes read 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 }