1989 lines
55 KiB
Go
1989 lines
55 KiB
Go
// Copyright (c) 2012-2020 Ugorji Nwoke. All rights reserved.
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// Use of this source code is governed by a MIT license found in the LICENSE file.
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package codec
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import (
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"encoding"
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"errors"
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"io"
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"reflect"
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"strconv"
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"time"
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)
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const (
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msgBadDesc = "unrecognized descriptor byte"
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)
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const (
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decDefMaxDepth = 1024 // maximum depth
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decDefSliceCap = 8
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decDefChanCap = 64 // should be large, as cap cannot be expanded
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decScratchByteArrayLen = (7 * 8) // ??? cacheLineSize +
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// decFailNonEmptyIntf configures whether we error
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// when decoding naked into a non-empty interface.
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//
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// Typically, we cannot decode non-nil stream value into
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// nil interface with methods (e.g. io.Reader).
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// However, in some scenarios, this should be allowed:
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// - MapType
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// - SliceType
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// - Extensions
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//
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// Consequently, we should relax this. Put it behind a const flag for now.
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decFailNonEmptyIntf = false
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)
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var (
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errNeedMapOrArrayDecodeToStruct = errors.New("only encoded map or array can decode into struct")
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errCannotDecodeIntoNil = errors.New("cannot decode into nil")
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errExpandSliceCannotChange = errors.New("expand slice: cannot change")
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errDecoderNotInitialized = errors.New("Decoder not initialized")
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errDecUnreadByteNothingToRead = errors.New("cannot unread - nothing has been read")
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errDecUnreadByteLastByteNotRead = errors.New("cannot unread - last byte has not been read")
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errDecUnreadByteUnknown = errors.New("cannot unread - reason unknown")
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errMaxDepthExceeded = errors.New("maximum decoding depth exceeded")
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)
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// decByteState tracks where the []byte returned by the last call
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// to DecodeBytes or DecodeStringAsByte came from
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type decByteState uint8
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const (
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decByteStateNone decByteState = iota
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decByteStateZerocopy // view into the []byte that we are decoding from
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decByteStateReuseBuf // view into the transient buffer used internally by the decDriver
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// decByteStateNewAlloc
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)
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type decDriver interface {
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// this will check if the next token is a break.
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CheckBreak() bool
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// TryNil tries to decode as nil.
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// If a nil is in the stream, it consumes it and returns true.
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//
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// Note: if TryNil returns true, that must be handled.
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TryNil() bool
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// ContainerType returns one of: Bytes, String, Nil, Slice or Map.
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//
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// Return unSet if not known.
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//
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// Note: Implementations MUST fully consume sentinel container types, specifically Nil.
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ContainerType() (vt valueType)
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// DecodeNaked will decode primitives (number, bool, string, []byte) and RawExt.
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// For maps and arrays, it will not do the decoding in-band, but will signal
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// the decoder, so that is done later, by setting the fauxUnion.valueType field.
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//
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// Note: Numbers are decoded as int64, uint64, float64 only (no smaller sized number types).
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// for extensions, DecodeNaked must read the tag and the []byte if it exists.
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// if the []byte is not read, then kInterfaceNaked will treat it as a Handle
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// that stores the subsequent value in-band, and complete reading the RawExt.
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//
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// extensions should also use readx to decode them, for efficiency.
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// kInterface will extract the detached byte slice if it has to pass it outside its realm.
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DecodeNaked()
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DecodeInt64() (i int64)
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DecodeUint64() (ui uint64)
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DecodeFloat64() (f float64)
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DecodeBool() (b bool)
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// DecodeStringAsBytes returns the bytes representing a string.
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// It will return a view into scratch buffer or input []byte (if applicable).
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//
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// Note: This can also decode symbols, if supported.
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//
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// Users should consume it right away and not store it for later use.
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DecodeStringAsBytes() (v []byte)
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// DecodeBytes returns the bytes representing a binary value.
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// It will return a view into scratch buffer or input []byte (if applicable).
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//
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// All implementations must honor the contract below:
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// if ZeroCopy and applicable, return a view into input []byte we are decoding from
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// else if in == nil, return a view into scratch buffer
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// else append decoded value to in[:0] and return that
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// (this can be simulated by passing []byte{} as in parameter)
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//
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// Implementations must also update Decoder.decByteState on each call to
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// DecodeBytes or DecodeStringAsBytes. Some callers may check that and work appropriately.
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//
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// Note: DecodeBytes may decode past the length of the passed byte slice, up to the cap.
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// Consequently, it is ok to pass a zero-len slice to DecodeBytes, as the returned
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// byte slice will have the appropriate length.
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DecodeBytes(in []byte) (out []byte)
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// DecodeBytes(bs []byte, isstring, zerocopy bool) (bsOut []byte)
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// DecodeExt will decode into a *RawExt or into an extension.
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DecodeExt(v interface{}, xtag uint64, ext Ext)
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// decodeExt(verifyTag bool, tag byte) (xtag byte, xbs []byte)
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DecodeTime() (t time.Time)
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// ReadArrayStart will return the length of the array.
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// If the format doesn't prefix the length, it returns containerLenUnknown.
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// If the expected array was a nil in the stream, it returns containerLenNil.
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ReadArrayStart() int
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ReadArrayEnd()
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// ReadMapStart will return the length of the array.
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// If the format doesn't prefix the length, it returns containerLenUnknown.
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// If the expected array was a nil in the stream, it returns containerLenNil.
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ReadMapStart() int
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ReadMapEnd()
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reset()
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atEndOfDecode()
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nextValueBytes(start []byte) []byte
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decoder() *Decoder
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}
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type decDriverContainerTracker interface {
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ReadArrayElem()
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ReadMapElemKey()
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ReadMapElemValue()
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}
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type decDriverNoopContainerReader struct{}
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func (x decDriverNoopContainerReader) ReadArrayStart() (v int) { return }
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func (x decDriverNoopContainerReader) ReadArrayEnd() {}
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func (x decDriverNoopContainerReader) ReadMapStart() (v int) { return }
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func (x decDriverNoopContainerReader) ReadMapEnd() {}
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func (x decDriverNoopContainerReader) CheckBreak() (v bool) { return }
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func (x decDriverNoopContainerReader) atEndOfDecode() {}
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// DecodeOptions captures configuration options during decode.
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type DecodeOptions struct {
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// MapType specifies type to use during schema-less decoding of a map in the stream.
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// If nil (unset), we default to map[string]interface{} iff json handle and MapKeyAsString=true,
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// else map[interface{}]interface{}.
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MapType reflect.Type
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// SliceType specifies type to use during schema-less decoding of an array in the stream.
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// If nil (unset), we default to []interface{} for all formats.
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SliceType reflect.Type
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// MaxInitLen defines the maxinum initial length that we "make" a collection
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// (string, slice, map, chan). If 0 or negative, we default to a sensible value
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// based on the size of an element in the collection.
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//
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// For example, when decoding, a stream may say that it has 2^64 elements.
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// We should not auto-matically provision a slice of that size, to prevent Out-Of-Memory crash.
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// Instead, we provision up to MaxInitLen, fill that up, and start appending after that.
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MaxInitLen int
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// ReaderBufferSize is the size of the buffer used when reading.
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//
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// if > 0, we use a smart buffer internally for performance purposes.
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ReaderBufferSize int
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// MaxDepth defines the maximum depth when decoding nested
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// maps and slices. If 0 or negative, we default to a suitably large number (currently 1024).
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MaxDepth int16
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// If ErrorIfNoField, return an error when decoding a map
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// from a codec stream into a struct, and no matching struct field is found.
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ErrorIfNoField bool
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// If ErrorIfNoArrayExpand, return an error when decoding a slice/array that cannot be expanded.
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// For example, the stream contains an array of 8 items, but you are decoding into a [4]T array,
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// or you are decoding into a slice of length 4 which is non-addressable (and so cannot be set).
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ErrorIfNoArrayExpand bool
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// If SignedInteger, use the int64 during schema-less decoding of unsigned values (not uint64).
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SignedInteger bool
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// MapValueReset controls how we decode into a map value.
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//
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// By default, we MAY retrieve the mapping for a key, and then decode into that.
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// However, especially with big maps, that retrieval may be expensive and unnecessary
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// if the stream already contains all that is necessary to recreate the value.
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//
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// If true, we will never retrieve the previous mapping,
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// but rather decode into a new value and set that in the map.
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//
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// If false, we will retrieve the previous mapping if necessary e.g.
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// the previous mapping is a pointer, or is a struct or array with pre-set state,
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// or is an interface.
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MapValueReset bool
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// SliceElementReset: on decoding a slice, reset the element to a zero value first.
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//
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// concern: if the slice already contained some garbage, we will decode into that garbage.
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SliceElementReset bool
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// InterfaceReset controls how we decode into an interface.
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//
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// By default, when we see a field that is an interface{...},
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// or a map with interface{...} value, we will attempt decoding into the
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// "contained" value.
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//
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// However, this prevents us from reading a string into an interface{}
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// that formerly contained a number.
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//
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// If true, we will decode into a new "blank" value, and set that in the interface.
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// If false, we will decode into whatever is contained in the interface.
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InterfaceReset bool
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// InternString controls interning of strings during decoding.
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//
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// Some handles, e.g. json, typically will read map keys as strings.
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// If the set of keys are finite, it may help reduce allocation to
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// look them up from a map (than to allocate them afresh).
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//
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// Note: Handles will be smart when using the intern functionality.
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// Every string should not be interned.
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// An excellent use-case for interning is struct field names,
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// or map keys where key type is string.
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InternString bool
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// PreferArrayOverSlice controls whether to decode to an array or a slice.
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//
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// This only impacts decoding into a nil interface{}.
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//
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// Consequently, it has no effect on codecgen.
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//
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// *Note*: This only applies if using go1.5 and above,
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// as it requires reflect.ArrayOf support which was absent before go1.5.
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PreferArrayOverSlice bool
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// DeleteOnNilMapValue controls how to decode a nil value in the stream.
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//
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// If true, we will delete the mapping of the key.
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// Else, just set the mapping to the zero value of the type.
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//
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// Deprecated: This does NOTHING and is left behind for compiling compatibility.
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// This change is necessitated because 'nil' in a stream now consistently
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// means the zero value (ie reset the value to its zero state).
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DeleteOnNilMapValue bool
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// RawToString controls how raw bytes in a stream are decoded into a nil interface{}.
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// By default, they are decoded as []byte, but can be decoded as string (if configured).
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RawToString bool
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// ZeroCopy controls whether decoded values of []byte or string type
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// point into the input []byte parameter passed to a NewDecoderBytes/ResetBytes(...) call.
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//
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// To illustrate, if ZeroCopy and decoding from a []byte (not io.Writer),
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// then a []byte or string in the output result may just be a slice of (point into)
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// the input bytes.
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//
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// This optimization prevents unnecessary copying.
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//
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// However, it is made optional, as the caller MUST ensure that the input parameter []byte is
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// not modified after the Decode() happens, as any changes are mirrored in the decoded result.
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ZeroCopy bool
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// PreferPointerForStructOrArray controls whether a struct or array
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// is stored in a nil interface{}, or a pointer to it.
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//
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// This mostly impacts when we decode registered extensions.
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PreferPointerForStructOrArray bool
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}
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// ----------------------------------------
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func (d *Decoder) rawExt(f *codecFnInfo, rv reflect.Value) {
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d.d.DecodeExt(rv2i(rv), 0, nil)
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}
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func (d *Decoder) ext(f *codecFnInfo, rv reflect.Value) {
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d.d.DecodeExt(rv2i(rv), f.xfTag, f.xfFn)
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}
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func (d *Decoder) selferUnmarshal(f *codecFnInfo, rv reflect.Value) {
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rv2i(rv).(Selfer).CodecDecodeSelf(d)
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}
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func (d *Decoder) binaryUnmarshal(f *codecFnInfo, rv reflect.Value) {
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bm := rv2i(rv).(encoding.BinaryUnmarshaler)
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xbs := d.d.DecodeBytes(nil)
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fnerr := bm.UnmarshalBinary(xbs)
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d.onerror(fnerr)
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}
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func (d *Decoder) textUnmarshal(f *codecFnInfo, rv reflect.Value) {
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tm := rv2i(rv).(encoding.TextUnmarshaler)
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fnerr := tm.UnmarshalText(d.d.DecodeStringAsBytes())
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d.onerror(fnerr)
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}
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func (d *Decoder) jsonUnmarshal(f *codecFnInfo, rv reflect.Value) {
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tm := rv2i(rv).(jsonUnmarshaler)
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// grab the bytes to be read, as UnmarshalJSON needs the full JSON so as to unmarshal it itself.
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bs := d.blist.get(256)
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bs = d.d.nextValueBytes(bs)
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fnerr := tm.UnmarshalJSON(bs)
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d.blist.put(bs)
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d.onerror(fnerr)
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}
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func (d *Decoder) kErr(f *codecFnInfo, rv reflect.Value) {
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d.errorf("no decoding function defined for kind %v", rv.Kind())
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}
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func (d *Decoder) raw(f *codecFnInfo, rv reflect.Value) {
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rvSetBytes(rv, d.rawBytes())
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}
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func (d *Decoder) kString(f *codecFnInfo, rv reflect.Value) {
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rvSetString(rv, d.stringZC(d.d.DecodeStringAsBytes()))
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}
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func (d *Decoder) kBool(f *codecFnInfo, rv reflect.Value) {
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rvSetBool(rv, d.d.DecodeBool())
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}
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func (d *Decoder) kTime(f *codecFnInfo, rv reflect.Value) {
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rvSetTime(rv, d.d.DecodeTime())
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}
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func (d *Decoder) kFloat32(f *codecFnInfo, rv reflect.Value) {
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rvSetFloat32(rv, d.decodeFloat32())
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}
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func (d *Decoder) kFloat64(f *codecFnInfo, rv reflect.Value) {
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rvSetFloat64(rv, d.d.DecodeFloat64())
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}
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func (d *Decoder) kInt(f *codecFnInfo, rv reflect.Value) {
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rvSetInt(rv, int(chkOvf.IntV(d.d.DecodeInt64(), intBitsize)))
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}
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func (d *Decoder) kInt8(f *codecFnInfo, rv reflect.Value) {
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rvSetInt8(rv, int8(chkOvf.IntV(d.d.DecodeInt64(), 8)))
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}
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func (d *Decoder) kInt16(f *codecFnInfo, rv reflect.Value) {
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rvSetInt16(rv, int16(chkOvf.IntV(d.d.DecodeInt64(), 16)))
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}
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func (d *Decoder) kInt32(f *codecFnInfo, rv reflect.Value) {
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rvSetInt32(rv, int32(chkOvf.IntV(d.d.DecodeInt64(), 32)))
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}
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func (d *Decoder) kInt64(f *codecFnInfo, rv reflect.Value) {
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rvSetInt64(rv, d.d.DecodeInt64())
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}
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func (d *Decoder) kUint(f *codecFnInfo, rv reflect.Value) {
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rvSetUint(rv, uint(chkOvf.UintV(d.d.DecodeUint64(), uintBitsize)))
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}
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func (d *Decoder) kUintptr(f *codecFnInfo, rv reflect.Value) {
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rvSetUintptr(rv, uintptr(chkOvf.UintV(d.d.DecodeUint64(), uintBitsize)))
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}
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func (d *Decoder) kUint8(f *codecFnInfo, rv reflect.Value) {
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rvSetUint8(rv, uint8(chkOvf.UintV(d.d.DecodeUint64(), 8)))
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}
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func (d *Decoder) kUint16(f *codecFnInfo, rv reflect.Value) {
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rvSetUint16(rv, uint16(chkOvf.UintV(d.d.DecodeUint64(), 16)))
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}
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func (d *Decoder) kUint32(f *codecFnInfo, rv reflect.Value) {
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rvSetUint32(rv, uint32(chkOvf.UintV(d.d.DecodeUint64(), 32)))
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}
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func (d *Decoder) kUint64(f *codecFnInfo, rv reflect.Value) {
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rvSetUint64(rv, d.d.DecodeUint64())
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}
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func (d *Decoder) kInterfaceNaked(f *codecFnInfo) (rvn reflect.Value) {
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// nil interface:
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// use some hieristics to decode it appropriately
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// based on the detected next value in the stream.
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n := d.naked()
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d.d.DecodeNaked()
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// We cannot decode non-nil stream value into nil interface with methods (e.g. io.Reader).
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// Howver, it is possible that the user has ways to pass in a type for a given interface
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// - MapType
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// - SliceType
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// - Extensions
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//
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// Consequently, we should relax this. Put it behind a const flag for now.
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if decFailNonEmptyIntf && f.ti.numMeth > 0 {
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d.errorf("cannot decode non-nil codec value into nil %v (%v methods)", f.ti.rt, f.ti.numMeth)
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}
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switch n.v {
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case valueTypeMap:
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mtid := d.mtid
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if mtid == 0 {
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if d.jsms { // if json, default to a map type with string keys
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mtid = mapStrIntfTypId // for json performance
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} else {
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mtid = mapIntfIntfTypId
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}
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}
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if mtid == mapStrIntfTypId {
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var v2 map[string]interface{}
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d.decode(&v2)
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rvn = rv4i(&v2).Elem()
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} else if mtid == mapIntfIntfTypId {
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var v2 map[interface{}]interface{}
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d.decode(&v2)
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rvn = rv4i(&v2).Elem()
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} else if d.mtr {
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rvn = reflect.New(d.h.MapType)
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d.decode(rv2i(rvn))
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rvn = rvn.Elem()
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} else {
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rvn = rvZeroAddrK(d.h.MapType, reflect.Map)
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d.decodeValue(rvn, nil)
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}
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case valueTypeArray:
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if d.stid == 0 || d.stid == intfSliceTypId {
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var v2 []interface{}
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d.decode(&v2)
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rvn = rv4i(&v2).Elem()
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} else if d.str {
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rvn = reflect.New(d.h.SliceType)
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d.decode(rv2i(rvn))
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rvn = rvn.Elem()
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} else {
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rvn = rvZeroAddrK(d.h.SliceType, reflect.Slice)
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d.decodeValue(rvn, nil)
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}
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if reflectArrayOfSupported && d.h.PreferArrayOverSlice {
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rvn = rvGetArray4Slice(rvn)
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}
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case valueTypeExt:
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tag, bytes := n.u, n.l // calling decode below might taint the values
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bfn := d.h.getExtForTag(tag)
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var re = RawExt{Tag: tag}
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if bytes == nil {
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// it is one of the InterfaceExt ones: json and cbor.
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// most likely cbor, as json decoding never reveals valueTypeExt (no tagging support)
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if bfn == nil {
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d.decode(&re.Value)
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rvn = rv4i(&re).Elem()
|
|
} else {
|
|
if bfn.ext == SelfExt {
|
|
rvn = rvZeroAddr(bfn.rt)
|
|
d.decodeValue(rvn, d.h.fnNoExt(bfn.rt))
|
|
} else {
|
|
rvn = reflect.New(bfn.rt)
|
|
d.interfaceExtConvertAndDecode(rv2i(rvn), bfn.ext)
|
|
rvn = rvn.Elem()
|
|
}
|
|
}
|
|
} else {
|
|
// one of the BytesExt ones: binc, msgpack, simple
|
|
if bfn == nil {
|
|
re.setData(bytes, false)
|
|
rvn = rv4i(&re).Elem()
|
|
} else {
|
|
rvn = reflect.New(bfn.rt)
|
|
if bfn.ext == SelfExt {
|
|
d.sideDecode(rv2i(rvn), bytes)
|
|
} else {
|
|
bfn.ext.ReadExt(rv2i(rvn), bytes)
|
|
}
|
|
rvn = rvn.Elem()
|
|
}
|
|
}
|
|
// if struct/array, directly store pointer into the interface
|
|
if d.h.PreferPointerForStructOrArray && rvn.CanAddr() {
|
|
if rk := rvn.Kind(); rk == reflect.Array || rk == reflect.Struct {
|
|
rvn = rvn.Addr()
|
|
}
|
|
}
|
|
case valueTypeNil:
|
|
// rvn = reflect.Zero(f.ti.rt)
|
|
// 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:
|
|
halt.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 d.h.InterfaceReset || rvIsNil(rv) {
|
|
// 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 {
|
|
setZeroRV(rv)
|
|
}
|
|
return
|
|
}
|
|
} else {
|
|
// now we have a non-nil interface value, meaning it contains a type
|
|
rvn = rv.Elem()
|
|
}
|
|
|
|
// 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())
|
|
|
|
if isDecodeable(rvn) {
|
|
d.decodeValue(rvn, nil)
|
|
return
|
|
}
|
|
|
|
rvn2 := rvZeroAddrK(rvType(rvn), rvn.Kind())
|
|
rvSetDirect(rvn2, rvn)
|
|
d.decodeValue(rvn2, nil)
|
|
rv.Set(rvn2)
|
|
}
|
|
|
|
func decStructFieldKeyNotString(dd decDriver, keyType valueType, b *[decScratchByteArrayLen]byte) (rvkencname []byte) {
|
|
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 {
|
|
halt.errorf("invalid struct key type: %v", keyType)
|
|
}
|
|
return
|
|
}
|
|
|
|
func (d *Decoder) kStruct(f *codecFnInfo, rv reflect.Value) {
|
|
ctyp := d.d.ContainerType()
|
|
var mf MissingFielder
|
|
if f.ti.flagMissingFielder {
|
|
mf = rv2i(rv).(MissingFielder)
|
|
} else if f.ti.flagMissingFielderPtr {
|
|
mf = rv2i(rv.Addr()).(MissingFielder)
|
|
}
|
|
if ctyp == valueTypeMap {
|
|
containerLen := d.mapStart()
|
|
if containerLen == 0 {
|
|
d.mapEnd()
|
|
return
|
|
}
|
|
hasLen := containerLen >= 0
|
|
var name2 []byte
|
|
if mf != nil {
|
|
var namearr2 [16]byte
|
|
name2 = namearr2[:0]
|
|
}
|
|
var rvkencname []byte
|
|
for j := 0; d.mapNext(j, containerLen, hasLen); j++ {
|
|
d.mapElemKey()
|
|
if f.ti.keyType == valueTypeString {
|
|
rvkencname = d.d.DecodeStringAsBytes()
|
|
} else {
|
|
rvkencname = decStructFieldKeyNotString(d.d, f.ti.keyType, &d.b)
|
|
}
|
|
d.mapElemValue()
|
|
if si := f.ti.siForEncName(stringView(rvkencname)); si != nil {
|
|
d.decodeValue(si.path.fieldAlloc(rv), nil)
|
|
} else if mf != nil {
|
|
// store rvkencname in new []byte, as it previously shares Decoder.b, which is used in decode
|
|
name2 = append(name2[:0], rvkencname...)
|
|
var f interface{}
|
|
d.decode(&f)
|
|
if !mf.CodecMissingField(name2, f) && d.h.ErrorIfNoField {
|
|
d.errorf("no matching struct field when decoding stream map with key: %s ", stringView(name2))
|
|
}
|
|
} else {
|
|
d.structFieldNotFound(-1, stringView(rvkencname))
|
|
}
|
|
}
|
|
d.mapEnd()
|
|
} else if ctyp == valueTypeArray {
|
|
containerLen := d.arrayStart()
|
|
if containerLen == 0 {
|
|
d.arrayEnd()
|
|
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 f.ti.sfiSrc {
|
|
if hasLen {
|
|
if j == containerLen {
|
|
break
|
|
}
|
|
} else if d.checkBreak() {
|
|
checkbreak = true
|
|
break
|
|
}
|
|
d.arrayElem()
|
|
d.decodeValue(si.path.fieldAlloc(rv), nil)
|
|
}
|
|
var proceed bool
|
|
if hasLen {
|
|
proceed = containerLen > len(f.ti.sfiSrc)
|
|
} else {
|
|
proceed = !checkbreak
|
|
}
|
|
// if (hasLen && containerLen > len(f.ti.sfiSrc)) || (!hasLen && !checkbreak) {
|
|
if proceed {
|
|
// read remaining values and throw away
|
|
for j := len(f.ti.sfiSrc); ; j++ {
|
|
if !d.mapNext(j, containerLen, hasLen) {
|
|
break
|
|
}
|
|
d.arrayElem()
|
|
d.structFieldNotFound(j, "")
|
|
}
|
|
}
|
|
d.arrayEnd()
|
|
} else {
|
|
d.onerror(errNeedMapOrArrayDecodeToStruct)
|
|
}
|
|
}
|
|
|
|
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).
|
|
|
|
// Note: rv is a slice type here - guaranteed
|
|
|
|
rvCanset := rv.CanSet()
|
|
|
|
ctyp := d.d.ContainerType()
|
|
if ctyp == valueTypeBytes || ctyp == valueTypeString {
|
|
// you can only decode bytes or string in the stream into a slice or array of bytes
|
|
if !(f.ti.rtid == uint8SliceTypId || f.ti.elemkind == uint8(reflect.Uint8)) {
|
|
d.errorf("bytes/string in stream must decode into slice/array of bytes, not %v", f.ti.rt)
|
|
}
|
|
rvbs := rvGetBytes(rv)
|
|
if !rvCanset {
|
|
// not addressable byte slice, so do not decode into it past the length
|
|
rvbs = rvbs[:len(rvbs):len(rvbs)]
|
|
}
|
|
bs2 := d.decodeBytesInto(rvbs)
|
|
if !(len(bs2) > 0 && len(bs2) == len(rvbs) && &bs2[0] == &rvbs[0]) {
|
|
if rvCanset {
|
|
rvSetBytes(rv, bs2)
|
|
} else if len(rvbs) > 0 && len(bs2) > 0 {
|
|
copy(rvbs, bs2)
|
|
}
|
|
}
|
|
return
|
|
}
|
|
|
|
slh, containerLenS := d.decSliceHelperStart() // only expects valueType(Array|Map) - never Nil
|
|
|
|
// an array can never return a nil slice. so no need to check f.array here.
|
|
if containerLenS == 0 {
|
|
if rvCanset {
|
|
if rvIsNil(rv) {
|
|
rvSetDirect(rv, rvSliceZeroCap(f.ti.rt))
|
|
} else {
|
|
rvSetSliceLen(rv, 0)
|
|
}
|
|
}
|
|
slh.End()
|
|
return
|
|
}
|
|
|
|
rtelem0Mut := !isImmutableKind(reflect.Kind(f.ti.elemkind))
|
|
rtelem := f.ti.elem
|
|
rtelemkind := rtelem.Kind()
|
|
for rtelemkind == reflect.Ptr {
|
|
rtelem = rtelem.Elem()
|
|
rtelemkind = rtelem.Kind()
|
|
}
|
|
|
|
var fn *codecFn
|
|
|
|
var rvChanged bool
|
|
|
|
var rv0 = rv
|
|
var rv9 reflect.Value
|
|
|
|
rvlen := rvLenSlice(rv)
|
|
rvcap := rvCapSlice(rv)
|
|
hasLen := containerLenS > 0
|
|
if hasLen {
|
|
if containerLenS > rvcap {
|
|
oldRvlenGtZero := rvlen > 0
|
|
rvlen1 := decInferLen(containerLenS, d.h.MaxInitLen, int(f.ti.elemsize))
|
|
if rvlen1 == rvlen {
|
|
} else if rvlen1 <= rvcap {
|
|
if rvCanset {
|
|
rvlen = rvlen1
|
|
rvSetSliceLen(rv, rvlen)
|
|
}
|
|
} else if rvCanset { // rvlen1 > rvcap
|
|
rvlen = rvlen1
|
|
rv = reflect.MakeSlice(f.ti.rt, rvlen, rvlen)
|
|
rvCanset = false
|
|
rvcap = rvlen
|
|
rvChanged = true
|
|
} else { // rvlen1 > rvcap && !canSet
|
|
d.errorf("cannot decode into non-settable slice")
|
|
}
|
|
if rvChanged && oldRvlenGtZero && rtelem0Mut {
|
|
rvCopySlice(rv, rv0) // only copy up to length NOT cap i.e. rv0.Slice(0, rvcap)
|
|
}
|
|
} else if containerLenS != rvlen {
|
|
if rvCanset {
|
|
rvlen = containerLenS
|
|
rvSetSliceLen(rv, rvlen)
|
|
}
|
|
}
|
|
}
|
|
|
|
// consider creating new element once, and just decoding into it.
|
|
var elemReset = d.h.SliceElementReset
|
|
|
|
var j int
|
|
|
|
for ; d.mapNext(j, containerLenS, hasLen); j++ {
|
|
if j == 0 && f.seq == seqTypeSlice && rvIsNil(rv) { // means hasLen = false
|
|
if rvCanset {
|
|
rvlen = decDefSliceCap
|
|
rvcap = rvlen + rvlen
|
|
rv = reflect.MakeSlice(f.ti.rt, rvlen, rvcap)
|
|
rvCanset = false
|
|
rvChanged = true
|
|
} else {
|
|
d.errorf("cannot decode into non-settable slice")
|
|
}
|
|
}
|
|
// if indefinite, etc, then expand the slice if necessary
|
|
if j >= rvlen {
|
|
if f.seq == seqTypeArray {
|
|
decArrayCannotExpand(slh, hasLen, rvlen, j, containerLenS)
|
|
return
|
|
}
|
|
slh.ElemContainerState(j)
|
|
|
|
// expand the slice up to the cap.
|
|
// Note that we did, so we have to reset it later.
|
|
|
|
if rvlen < rvcap {
|
|
rvlen = rvcap
|
|
if rvCanset {
|
|
rvSetSliceLen(rv, rvlen)
|
|
} else if rvChanged {
|
|
rv = rvSlice(rv, rvlen)
|
|
} else {
|
|
d.onerror(errExpandSliceCannotChange)
|
|
}
|
|
} else {
|
|
if !(rvCanset || rvChanged) {
|
|
d.onerror(errExpandSliceCannotChange)
|
|
}
|
|
rvcap = int(growCap(uint(rvcap), uint(f.ti.elemsize), 1))
|
|
rvlen = rvcap
|
|
rv9 = reflect.MakeSlice(f.ti.rt, rvlen, rvcap)
|
|
rvCopySlice(rv9, rv)
|
|
rv = rv9
|
|
rvCanset = false
|
|
rvChanged = true
|
|
}
|
|
} else {
|
|
slh.ElemContainerState(j)
|
|
}
|
|
rv9 = rvSliceIndex(rv, j, f.ti)
|
|
if elemReset {
|
|
// rv9.Set(rtelem0Zero) // elem0Zero initialized to rvZeroK(f.ti.elem, f.ti.elemkind)
|
|
rvSetDirectZero(rv9)
|
|
}
|
|
|
|
if fn == nil {
|
|
fn = d.h.fn(rtelem)
|
|
}
|
|
d.decodeValue(rv9, fn)
|
|
}
|
|
if j < rvlen {
|
|
if rvCanset {
|
|
rvSetSliceLen(rv, j)
|
|
} else if rvChanged {
|
|
rv = rvSlice(rv, j)
|
|
}
|
|
// rvlen = j
|
|
} else if j == 0 && rvIsNil(rv) {
|
|
if rvCanset {
|
|
rv = rvSliceZeroCap(f.ti.rt)
|
|
rvCanset = false
|
|
rvChanged = true
|
|
}
|
|
}
|
|
slh.End()
|
|
|
|
if rvChanged { // infers rvCanset=true, so it can be reset
|
|
rv0.Set(rv)
|
|
}
|
|
}
|
|
|
|
func (d *Decoder) kSliceForChan(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).
|
|
|
|
if f.ti.chandir&uint8(reflect.SendDir) == 0 {
|
|
d.errorf("receive-only channel cannot be decoded")
|
|
}
|
|
ctyp := d.d.ContainerType()
|
|
if ctyp == valueTypeBytes || ctyp == valueTypeString {
|
|
// you can only decode bytes or string in the stream into a slice or array of bytes
|
|
if !(f.ti.rtid == uint8SliceTypId || f.ti.elemkind == uint8(reflect.Uint8)) {
|
|
d.errorf("bytes/string in stream must decode into slice/array of bytes, not %v", f.ti.rt)
|
|
}
|
|
bs2 := d.d.DecodeBytes(nil)
|
|
irv := rv2i(rv)
|
|
ch, ok := irv.(chan<- byte)
|
|
if !ok {
|
|
ch = irv.(chan byte)
|
|
}
|
|
for _, b := range bs2 {
|
|
ch <- b
|
|
}
|
|
return
|
|
}
|
|
|
|
var rvCanset = rv.CanSet()
|
|
|
|
// only expects valueType(Array|Map - nil handled above)
|
|
slh, containerLenS := d.decSliceHelperStart()
|
|
|
|
// an array can never return a nil slice. so no need to check f.array here.
|
|
if containerLenS == 0 {
|
|
if rvCanset && rvIsNil(rv) {
|
|
rvSetDirect(rv, reflect.MakeChan(f.ti.rt, 0))
|
|
}
|
|
slh.End()
|
|
return
|
|
}
|
|
|
|
rtelem0Mut := !isImmutableKind(reflect.Kind(f.ti.elemkind))
|
|
rtelem := f.ti.elem
|
|
rtelemkind := rtelem.Kind()
|
|
for rtelemkind == reflect.Ptr {
|
|
rtelem = rtelem.Elem()
|
|
rtelemkind = rtelem.Kind()
|
|
}
|
|
|
|
var fn *codecFn
|
|
|
|
var rvChanged bool
|
|
var rv0 = rv
|
|
var rv9 reflect.Value
|
|
|
|
var rvlen int // := rv.Len()
|
|
hasLen := containerLenS > 0
|
|
|
|
var j int
|
|
|
|
for ; d.mapNext(j, containerLenS, hasLen); j++ {
|
|
if j == 0 && rvIsNil(rv) {
|
|
if hasLen {
|
|
rvlen = decInferLen(containerLenS, d.h.MaxInitLen, int(f.ti.elemsize))
|
|
} else {
|
|
rvlen = decDefChanCap
|
|
}
|
|
if rvCanset {
|
|
rv = reflect.MakeChan(f.ti.rt, rvlen)
|
|
rvChanged = true
|
|
} else {
|
|
d.errorf("cannot decode into non-settable chan")
|
|
}
|
|
}
|
|
slh.ElemContainerState(j)
|
|
if rtelem0Mut || !rv9.IsValid() { // || (f.ti.elemkind == reflect.Ptr && rvIsNil(rv9)) {
|
|
rv9 = rvZeroAddrK(f.ti.elem, reflect.Kind(f.ti.elemkind))
|
|
}
|
|
if fn == nil {
|
|
fn = d.h.fn(rtelem)
|
|
}
|
|
d.decodeValue(rv9, fn)
|
|
rv.Send(rv9)
|
|
}
|
|
slh.End()
|
|
|
|
if rvChanged { // infers rvCanset=true, so it can be reset
|
|
rv0.Set(rv)
|
|
}
|
|
|
|
}
|
|
|
|
func (d *Decoder) kMap(f *codecFnInfo, rv reflect.Value) {
|
|
containerLen := d.mapStart()
|
|
ti := f.ti
|
|
if rvIsNil(rv) {
|
|
rvlen := decInferLen(containerLen, d.h.MaxInitLen, int(ti.keysize+ti.elemsize))
|
|
rvSetDirect(rv, makeMapReflect(ti.rt, rvlen))
|
|
}
|
|
|
|
if containerLen == 0 {
|
|
d.mapEnd()
|
|
return
|
|
}
|
|
|
|
ktype, vtype := ti.key, ti.elem
|
|
ktypeId := rt2id(ktype)
|
|
vtypeKind := vtype.Kind()
|
|
ktypeKind := ktype.Kind()
|
|
|
|
var vtypeElem reflect.Type
|
|
|
|
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() {
|
|
}
|
|
|
|
rvvMut := !isImmutableKind(vtypeKind)
|
|
rvvCanNil := isnilBitset.isset(byte(vtypeKind))
|
|
var vtypeIsPtr, vtypeIsMap bool
|
|
if rvvMut {
|
|
vtypeIsPtr = vtypeKind == reflect.Ptr
|
|
vtypeIsMap = vtypeKind == reflect.Ptr
|
|
}
|
|
|
|
var rvk, rvkn, rvv, rvvn, rvva, rvvz reflect.Value
|
|
|
|
// we do a doMapGet if kind is mutable, and InterfaceReset=true if interface
|
|
var doMapGet, doMapSet bool
|
|
|
|
if !d.h.MapValueReset {
|
|
if rvvMut && (vtypeKind != reflect.Interface || !d.h.InterfaceReset) {
|
|
doMapGet = true
|
|
rvva = mapAddrLoopvarRV(vtype, vtypeKind)
|
|
if vtypeKind == reflect.Ptr {
|
|
vtypeElem = vtype.Elem()
|
|
}
|
|
}
|
|
}
|
|
|
|
rvkMut := !isImmutableKind(ktype.Kind()) // if ktype is immutable, then re-use the same rvk.
|
|
ktypeIsString := ktypeId == stringTypId
|
|
ktypeIsIntf := ktypeId == intfTypId
|
|
|
|
hasLen := containerLen > 0
|
|
|
|
// kstrbs is used locally for the key bytes, so we can reduce allocation.
|
|
// When we read keys, we copy to this local bytes array, and use a stringView for lookup.
|
|
// We only convert it into a true string if we have to do a set on the map.
|
|
var kstrarr [64]byte // most keys are less than 32 bytes, and even more less than 64
|
|
var kstrbs = kstrarr[:0]
|
|
var kstr2bs []byte
|
|
var s string
|
|
|
|
var callFnRvk bool
|
|
|
|
fnRvk2 := func() (s string) {
|
|
callFnRvk = false
|
|
if len(kstr2bs) < 2 {
|
|
return string(kstr2bs)
|
|
}
|
|
if safeMode {
|
|
return d.string(kstr2bs)
|
|
}
|
|
// unsafe mode below
|
|
if d.decByteState == decByteStateZerocopy && d.h.ZeroCopy {
|
|
return stringView(kstr2bs)
|
|
}
|
|
callFnRvk = true
|
|
if d.decByteState == decByteStateReuseBuf {
|
|
kstrbs = append(kstrbs[:0], kstr2bs...)
|
|
kstr2bs = kstrbs
|
|
}
|
|
return stringView(kstr2bs)
|
|
}
|
|
|
|
for j := 0; d.mapNext(j, containerLen, hasLen); j++ {
|
|
callFnRvk = false
|
|
if j == 0 {
|
|
if !rvkMut {
|
|
rvkn = rvZeroAddrK(ktype, ktypeKind)
|
|
}
|
|
if !rvvMut {
|
|
rvvn = rvZeroAddrK(vtype, vtypeKind)
|
|
}
|
|
if !ktypeIsString && keyFn == nil {
|
|
keyFn = d.h.fn(ktypeLo)
|
|
}
|
|
if valFn == nil {
|
|
valFn = d.h.fn(vtypeLo)
|
|
}
|
|
}
|
|
|
|
if rvkMut {
|
|
rvk = rvZeroAddrK(ktype, ktypeKind)
|
|
} else {
|
|
rvk = rvkn
|
|
}
|
|
|
|
d.mapElemKey()
|
|
if ktypeIsString {
|
|
kstr2bs = d.d.DecodeStringAsBytes()
|
|
rvSetString(rvk, fnRvk2())
|
|
} else {
|
|
d.decByteState = decByteStateNone
|
|
d.decodeValue(rvk, keyFn)
|
|
// special case if interface wrapping a byte array.
|
|
if ktypeIsIntf {
|
|
if rvk2 := rvk.Elem(); rvk2.IsValid() && rvType(rvk2) == uint8SliceTyp {
|
|
kstr2bs = rvGetBytes(rvk2)
|
|
rvk.Set(rv4i(fnRvk2()))
|
|
}
|
|
// NOTE: consider failing early if map/slice/func
|
|
}
|
|
}
|
|
|
|
d.mapElemValue()
|
|
|
|
if d.d.TryNil() {
|
|
// since a map, we have to set zero value if needed
|
|
if !rvvz.IsValid() {
|
|
rvvz = rvZeroK(vtype, vtypeKind)
|
|
}
|
|
if callFnRvk {
|
|
s = d.string(kstr2bs)
|
|
if ktypeIsString {
|
|
rvSetString(rvk, s)
|
|
} else { // ktypeIsIntf
|
|
rvk.Set(rv4i(s))
|
|
}
|
|
}
|
|
mapSet(rv, rvk, rvvz)
|
|
continue
|
|
}
|
|
|
|
// there is non-nil content in the stream to decode ...
|
|
|
|
// set doMapSet to false if u do a get, and its a non-nil pointer, else keep as true
|
|
doMapSet = true
|
|
|
|
if rvvMut {
|
|
if doMapGet {
|
|
rvv = mapGet(rv, rvk, rvva)
|
|
if rvv.IsValid() && (!rvvCanNil || (rvvCanNil && !rvIsNil(rvv))) {
|
|
if vtypeIsPtr {
|
|
doMapSet = false
|
|
} else if vtypeKind != reflect.Map { // ok to decode directly into map
|
|
// make addressable (so you can set the slice/array elements or interface, etc)
|
|
rvvn = rvZeroAddrK(vtype, vtypeKind)
|
|
rvvn.Set(rvv)
|
|
rvv = rvvn
|
|
}
|
|
} else {
|
|
if vtypeIsMap {
|
|
rvv = reflect.New(vtypeElem)
|
|
} else {
|
|
rvv = rvZeroAddrK(vtype, vtypeKind)
|
|
}
|
|
}
|
|
} else {
|
|
rvv = rvZeroAddrK(vtype, vtypeKind)
|
|
}
|
|
} else {
|
|
rvv = rvvn
|
|
}
|
|
|
|
d.decodeValueNoCheckNil(rvv, valFn)
|
|
|
|
if doMapSet {
|
|
if callFnRvk {
|
|
s = d.string(kstr2bs)
|
|
if ktypeIsString {
|
|
rvSetString(rvk, s)
|
|
} else { // ktypeIsIntf
|
|
rvk.Set(rv4i(s))
|
|
}
|
|
}
|
|
mapSet(rv, rvk, rvv)
|
|
}
|
|
}
|
|
|
|
d.mapEnd()
|
|
}
|
|
|
|
// Decoder reads and decodes an object from an input stream in a supported format.
|
|
//
|
|
// Decoder is NOT safe for concurrent use i.e. a Decoder cannot be used
|
|
// concurrently in multiple goroutines.
|
|
//
|
|
// However, as Decoder could be allocation heavy to initialize, a Reset method is provided
|
|
// so its state can be reused to decode new input streams repeatedly.
|
|
// This is the idiomatic way to use.
|
|
type Decoder struct {
|
|
panicHdl
|
|
|
|
d decDriver
|
|
|
|
// cache the mapTypeId and sliceTypeId for faster comparisons
|
|
mtid uintptr
|
|
stid uintptr
|
|
|
|
h *BasicHandle
|
|
|
|
blist bytesFreelist
|
|
|
|
// ---- cpu cache line boundary?
|
|
decRd
|
|
|
|
// ---- cpu cache line boundary?
|
|
n fauxUnion
|
|
|
|
hh Handle
|
|
err error
|
|
|
|
// used for interning strings
|
|
is internerMap
|
|
|
|
// ---- cpu cache line boundary?
|
|
// ---- writable fields during execution --- *try* to keep in sep cache line
|
|
maxdepth int16
|
|
depth int16
|
|
|
|
// Extensions can call Decode() within a current Decode() call.
|
|
// We need to know when the top level Decode() call returns,
|
|
// so we can decide whether to Release() or not.
|
|
calls uint16 // what depth in mustDecode are we in now.
|
|
|
|
c containerState
|
|
|
|
decByteState
|
|
|
|
// b is an always-available scratch buffer used by Decoder and decDrivers.
|
|
// By being always-available, it can be used for one-off things without
|
|
// having to get from freelist, use, and return back to freelist.
|
|
b [decScratchByteArrayLen]byte
|
|
}
|
|
|
|
// NewDecoder returns a Decoder for decoding a stream of bytes from an io.Reader.
|
|
//
|
|
// For efficiency, Users are encouraged to configure ReaderBufferSize on the handle
|
|
// OR pass in a memory buffered reader (eg bufio.Reader, bytes.Buffer).
|
|
func NewDecoder(r io.Reader, h Handle) *Decoder {
|
|
d := h.newDecDriver().decoder()
|
|
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 := h.newDecDriver().decoder()
|
|
d.ResetBytes(in)
|
|
return d
|
|
}
|
|
|
|
func NewDecoderString(s string, h Handle) *Decoder {
|
|
return NewDecoderBytes(bytesView(s), h)
|
|
}
|
|
|
|
func (d *Decoder) r() *decRd {
|
|
return &d.decRd
|
|
}
|
|
|
|
func (d *Decoder) init(h Handle) {
|
|
initHandle(h)
|
|
d.bytes = true
|
|
d.err = errDecoderNotInitialized
|
|
d.h = h.getBasicHandle()
|
|
d.hh = h
|
|
d.be = h.isBinary()
|
|
if d.h.InternString && d.is == nil {
|
|
d.is.init()
|
|
}
|
|
// NOTE: do not initialize d.n here. It is lazily initialized in d.naked()
|
|
}
|
|
|
|
func (d *Decoder) resetCommon() {
|
|
d.d.reset()
|
|
d.err = nil
|
|
d.depth = 0
|
|
d.calls = 0
|
|
d.maxdepth = decDefMaxDepth
|
|
if d.h.MaxDepth > 0 {
|
|
d.maxdepth = d.h.MaxDepth
|
|
}
|
|
// reset all things which were cached from the Handle, but could change
|
|
d.mtid = 0
|
|
d.stid = 0
|
|
d.mtr = false
|
|
d.str = false
|
|
if d.h.MapType != nil {
|
|
d.mtid = rt2id(d.h.MapType)
|
|
d.mtr = fastpathAvIndex(d.mtid) != -1
|
|
}
|
|
if d.h.SliceType != nil {
|
|
d.stid = rt2id(d.h.SliceType)
|
|
d.str = fastpathAvIndex(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 {
|
|
r = &eofReader
|
|
}
|
|
d.bytes = false
|
|
if d.h.ReaderBufferSize > 0 {
|
|
if d.bi == nil {
|
|
d.bi = new(bufioDecReader)
|
|
}
|
|
d.bi.reset(r, d.h.ReaderBufferSize, &d.blist)
|
|
d.bufio = true
|
|
d.decReader = d.bi
|
|
} else {
|
|
if d.ri == nil {
|
|
d.ri = new(ioDecReader)
|
|
}
|
|
d.ri.reset(r, &d.blist)
|
|
d.bufio = false
|
|
d.decReader = 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 {
|
|
in = []byte{}
|
|
}
|
|
d.bufio = false
|
|
d.bytes = true
|
|
d.decReader = &d.rb
|
|
d.rb.reset(in)
|
|
d.resetCommon()
|
|
}
|
|
|
|
func (d *Decoder) ResetString(s string) {
|
|
d.ResetBytes(bytesView(s))
|
|
}
|
|
|
|
func (d *Decoder) naked() *fauxUnion {
|
|
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 i.e. the values
|
|
// in these containers will not be zero'ed before decoding.
|
|
// - 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).
|
|
//
|
|
// This in-place update maintains consistency in the decoding philosophy (i.e. we ALWAYS update
|
|
// in place by default). However, the consequence of this is that values in slices or maps
|
|
// which are not zero'ed before hand, will have part of the prior values in place after decode
|
|
// if the stream doesn't contain an update for those parts.
|
|
//
|
|
// This in-place update can be disabled by configuring the MapValueReset and SliceElementReset
|
|
// decode options available on every handle.
|
|
//
|
|
// Furthermore, 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) {
|
|
// tried to use closure, as runtime optimizes defer with no params.
|
|
// This seemed to be causing weird issues (like circular reference found, unexpected panic, etc).
|
|
// Also, see https://github.com/golang/go/issues/14939#issuecomment-417836139
|
|
defer func() {
|
|
if x := recover(); x != nil {
|
|
panicValToErr(d, x, &d.err)
|
|
err = d.err
|
|
}
|
|
}()
|
|
|
|
d.MustDecode(v)
|
|
return
|
|
}
|
|
|
|
// MustDecode is like Decode, but panics if unable to Decode.
|
|
//
|
|
// Note: This provides insight to the code location that triggered the error.
|
|
func (d *Decoder) MustDecode(v interface{}) {
|
|
halt.onerror(d.err)
|
|
if d.hh == nil {
|
|
halt.onerror(errNoFormatHandle)
|
|
}
|
|
|
|
// Top-level: v is a pointer and not nil.
|
|
d.calls++
|
|
d.decode(v)
|
|
d.calls--
|
|
if d.calls == 0 {
|
|
d.d.atEndOfDecode()
|
|
}
|
|
}
|
|
|
|
// Release releases shared (pooled) resources.
|
|
//
|
|
// It is important to call Release() when done with a Decoder, so those resources
|
|
// are released instantly for use by subsequently created Decoders.
|
|
//
|
|
// By default, Release() is automatically called unless the option ExplicitRelease is set.
|
|
//
|
|
// Deprecated: Release is a no-op as pooled resources are not used with an Decoder.
|
|
// This method is kept for compatibility reasons only.
|
|
func (d *Decoder) Release() {
|
|
}
|
|
|
|
func (d *Decoder) swallow() {
|
|
bs := d.blist.get(256)
|
|
bs = d.d.nextValueBytes(bs) // discard it
|
|
d.blist.put(bs)
|
|
}
|
|
|
|
func (d *Decoder) swallowErr() (err error) {
|
|
bs := d.blist.get(256)
|
|
defer func() {
|
|
panicToErr(d, &err)
|
|
d.blist.put(bs)
|
|
}()
|
|
bs = d.d.nextValueBytes(bs) // discard it
|
|
return
|
|
}
|
|
|
|
func setZero(iv interface{}) {
|
|
if iv == nil {
|
|
return
|
|
}
|
|
rv, ok := isNil(iv)
|
|
if ok {
|
|
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 *[]byte:
|
|
*v = nil
|
|
case *Raw:
|
|
*v = nil
|
|
case *time.Time:
|
|
*v = time.Time{}
|
|
case reflect.Value:
|
|
setZeroRV(v)
|
|
default:
|
|
if !fastpathDecodeSetZeroTypeSwitch(iv) {
|
|
setZeroRV(rv)
|
|
}
|
|
}
|
|
}
|
|
|
|
func setZeroRV(v reflect.Value) {
|
|
// If not decodeable (settable), we do not touch it.
|
|
// We considered empty'ing it if not decodeable e.g.
|
|
// - if chan, drain it
|
|
// - if map, clear it
|
|
// - if slice or array, zero all elements up to len
|
|
//
|
|
// However, we decided instead that we either will set the
|
|
// whole value to the zero value, or leave AS IS.
|
|
|
|
k := v.Kind()
|
|
if k == reflect.Ptr || k == reflect.Interface {
|
|
v = v.Elem()
|
|
}
|
|
if v.CanSet() {
|
|
rvSetDirectZero(v)
|
|
}
|
|
}
|
|
|
|
func (d *Decoder) decode(iv interface{}) {
|
|
// a switch with only concrete types can be optimized.
|
|
// consequently, we deal with nil and interfaces outside the switch.
|
|
|
|
if iv == nil {
|
|
d.onerror(errCannotDecodeIntoNil)
|
|
}
|
|
|
|
switch v := iv.(type) {
|
|
// case nil:
|
|
// case Selfer:
|
|
case reflect.Value:
|
|
if !isDecodeable(v) {
|
|
d.haltAsNotDecodeable(v)
|
|
}
|
|
d.decodeValue(v, nil)
|
|
case *string:
|
|
*v = d.stringZC(d.d.DecodeStringAsBytes())
|
|
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:
|
|
*v = float32(d.decodeFloat32())
|
|
case *float64:
|
|
*v = d.d.DecodeFloat64()
|
|
case *[]byte:
|
|
*v = d.decodeBytesInto(*v)
|
|
case []byte:
|
|
// not addressable byte slice, so do not decode into it past the length
|
|
b := d.decodeBytesInto(v[:len(v):len(v)])
|
|
if !(len(b) > 0 && len(b) == len(v) && &b[0] == &v[0]) { // not same slice
|
|
copy(v, b)
|
|
}
|
|
case *time.Time:
|
|
*v = d.d.DecodeTime()
|
|
case *Raw:
|
|
*v = d.rawBytes()
|
|
|
|
case *interface{}:
|
|
d.decodeValue(rv4i(iv), nil)
|
|
|
|
default:
|
|
// we can't check non-predefined types, as they might be a Selfer or extension.
|
|
if skipFastpathTypeSwitchInDirectCall || !fastpathDecodeTypeSwitch(iv, d) {
|
|
v := rv4i(iv)
|
|
if !isDecodeable(v) {
|
|
d.haltAsNotDecodeable(v)
|
|
}
|
|
d.decodeValue(v, nil)
|
|
}
|
|
}
|
|
}
|
|
|
|
// decodeValue MUST be called by the actual value we want to decode into,
|
|
// not its addr or a reference to it.
|
|
//
|
|
// This way, we know if it is itself a pointer, and can handle nil in
|
|
// the stream effectively.
|
|
//
|
|
// Note that decodeValue will handle nil in the stream early, so that the
|
|
// subsequent calls i.e. kXXX methods, etc do not have to handle it themselves.
|
|
func (d *Decoder) decodeValue(rv reflect.Value, fn *codecFn) {
|
|
if d.d.TryNil() {
|
|
setZeroRV(rv)
|
|
return
|
|
}
|
|
d.decodeValueNoCheckNil(rv, fn)
|
|
}
|
|
|
|
func (d *Decoder) decodeValueNoCheckNil(rv reflect.Value, fn *codecFn) {
|
|
// 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
|
|
PTR:
|
|
if rv.Kind() == reflect.Ptr {
|
|
rvpValid = true
|
|
if rvIsNil(rv) {
|
|
rvSetDirect(rv, reflect.New(rvType(rv).Elem()))
|
|
}
|
|
rvp = rv
|
|
rv = rv.Elem()
|
|
goto PTR
|
|
}
|
|
|
|
if fn == nil {
|
|
fn = d.h.fn(rvType(rv))
|
|
}
|
|
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.addrDf {
|
|
d.errorf("cannot decode into a non-pointer value")
|
|
} else {
|
|
fn.fd(d, &fn.i, rv)
|
|
}
|
|
} else {
|
|
fn.fd(d, &fn.i, 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)
|
|
} else if rvkencname != "" {
|
|
d.errorf("no matching struct field found when decoding stream map with key " + rvkencname)
|
|
}
|
|
}
|
|
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 (d *Decoder) ensureDecodeable(rv reflect.Value) {
|
|
// if !isDecodeable(rv) {
|
|
// d.haltAsNotDecodeable(rv)
|
|
// }
|
|
// }
|
|
|
|
func (d *Decoder) haltAsNotDecodeable(rv reflect.Value) {
|
|
if !rv.IsValid() {
|
|
d.onerror(errCannotDecodeIntoNil)
|
|
}
|
|
if !rv.CanInterface() {
|
|
d.errorf("cannot decode into a value without an interface: %v", rv)
|
|
}
|
|
d.errorf("cannot decode into value of kind: %v, %#v", rv.Kind(), rv2i(rv))
|
|
}
|
|
|
|
func (d *Decoder) depthIncr() {
|
|
d.depth++
|
|
if d.depth >= d.maxdepth {
|
|
d.onerror(errMaxDepthExceeded)
|
|
}
|
|
}
|
|
|
|
func (d *Decoder) depthDecr() {
|
|
d.depth--
|
|
}
|
|
|
|
// Possibly get an interned version of a string, iff InternString=true and decoding a map key.
|
|
//
|
|
// 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 || d.c != containerMapKey || len(v) < 2 || len(v) > internMaxStrLen {
|
|
return string(v)
|
|
}
|
|
return d.is.string(v)
|
|
}
|
|
|
|
func (d *Decoder) stringZC(v []byte) (s string) {
|
|
if !safeMode && d.decByteState == decByteStateZerocopy && d.h.ZeroCopy {
|
|
return stringView(v)
|
|
}
|
|
return d.string(v)
|
|
}
|
|
|
|
func (d *Decoder) zerocopy() bool {
|
|
return d.bytes && d.h.ZeroCopy
|
|
}
|
|
|
|
// decodeBytesInto is a convenience delegate function to decDriver.DecodeBytes.
|
|
// It ensures that `in` is not a nil byte, before calling decDriver.DecodeBytes,
|
|
// as decDriver.DecodeBytes treats a nil as a hint to use its internal scratch buffer.
|
|
func (d *Decoder) decodeBytesInto(in []byte) (v []byte) {
|
|
if in == nil {
|
|
in = []byte{}
|
|
}
|
|
return d.d.DecodeBytes(in)
|
|
}
|
|
|
|
func (d *Decoder) rawBytes() (v []byte) {
|
|
// ensure that this is not a view into the bytes
|
|
// i.e. if necessary, make new copy always.
|
|
return d.d.nextValueBytes(nil)
|
|
}
|
|
|
|
func (d *Decoder) wrapErr(v error, err *error) {
|
|
*err = wrapCodecErr(v, d.hh.Name(), d.NumBytesRead(), false)
|
|
}
|
|
|
|
// NumBytesRead returns the number of bytes read
|
|
func (d *Decoder) NumBytesRead() int {
|
|
return int(d.r().numread())
|
|
}
|
|
|
|
// decodeFloat32 will delegate to an appropriate DecodeFloat32 implementation (if exists),
|
|
// else if will call DecodeFloat64 and ensure the value doesn't overflow.
|
|
//
|
|
// Note that we return float64 to reduce unnecessary conversions
|
|
func (d *Decoder) decodeFloat32() float32 {
|
|
if d.js {
|
|
return d.jsondriver().DecodeFloat32() // custom implementation for 32-bit
|
|
}
|
|
return float32(chkOvf.Float32V(d.d.DecodeFloat64()))
|
|
}
|
|
|
|
// ---- container tracking
|
|
// Note: We update the .c after calling the callback.
|
|
// This way, the callback can know what the last status was.
|
|
|
|
// MARKER: do not call mapEnd if mapStart returns containerLenNil.
|
|
|
|
func (d *Decoder) mapNext(j, containerLen int, hasLen bool) bool {
|
|
// return (hasLen && j < containerLen) || !(hasLen || slh.d.checkBreak())
|
|
if hasLen {
|
|
return j < containerLen
|
|
}
|
|
return !d.checkBreak()
|
|
}
|
|
|
|
func (d *Decoder) mapStart() (v int) {
|
|
v = d.d.ReadMapStart()
|
|
if v != containerLenNil {
|
|
d.depthIncr()
|
|
d.c = containerMapStart
|
|
}
|
|
return
|
|
}
|
|
|
|
func (d *Decoder) mapElemKey() {
|
|
if d.js {
|
|
d.jsondriver().ReadMapElemKey()
|
|
}
|
|
d.c = containerMapKey
|
|
}
|
|
|
|
func (d *Decoder) mapElemValue() {
|
|
if d.js {
|
|
d.jsondriver().ReadMapElemValue()
|
|
}
|
|
d.c = containerMapValue
|
|
}
|
|
|
|
func (d *Decoder) mapEnd() {
|
|
d.d.ReadMapEnd()
|
|
d.depthDecr()
|
|
d.c = 0
|
|
}
|
|
|
|
func (d *Decoder) arrayStart() (v int) {
|
|
v = d.d.ReadArrayStart()
|
|
if v != containerLenNil {
|
|
d.depthIncr()
|
|
d.c = containerArrayStart
|
|
}
|
|
return
|
|
}
|
|
|
|
func (d *Decoder) arrayElem() {
|
|
if d.js {
|
|
d.jsondriver().ReadArrayElem()
|
|
}
|
|
d.c = containerArrayElem
|
|
}
|
|
|
|
func (d *Decoder) arrayEnd() {
|
|
d.d.ReadArrayEnd()
|
|
d.depthDecr()
|
|
d.c = 0
|
|
}
|
|
|
|
func (d *Decoder) interfaceExtConvertAndDecode(v interface{}, ext Ext) {
|
|
// var v interface{} = ext.ConvertExt(rv)
|
|
// d.d.decode(&v)
|
|
// ext.UpdateExt(rv, v)
|
|
|
|
// assume v is a pointer:
|
|
// - if struct|array, pass as is to ConvertExt
|
|
// - else make it non-addressable and pass to ConvertExt
|
|
// - make return value from ConvertExt addressable
|
|
// - decode into it
|
|
// - return the interface for passing into UpdateExt.
|
|
// - interface should be a pointer if struct|array, else a value
|
|
|
|
var s interface{}
|
|
rv := rv4i(v)
|
|
rv2 := rv.Elem()
|
|
rvk := rv2.Kind()
|
|
if rvk == reflect.Struct || rvk == reflect.Array {
|
|
s = ext.ConvertExt(v)
|
|
} else {
|
|
s = ext.ConvertExt(rv2i(rv2))
|
|
}
|
|
rv = rv4i(s)
|
|
if !rv.CanAddr() {
|
|
if rv.Kind() == reflect.Ptr {
|
|
rv2 = reflect.New(rvType(rv).Elem())
|
|
} else {
|
|
rv2 = rvZeroAddrK(rvType(rv), rv.Kind())
|
|
}
|
|
rvSetDirect(rv2, rv)
|
|
rv = rv2
|
|
}
|
|
d.decodeValue(rv, nil)
|
|
ext.UpdateExt(v, rv2i(rv))
|
|
}
|
|
|
|
func (d *Decoder) sideDecode(v interface{}, bs []byte) {
|
|
rv := baseRV(v)
|
|
NewDecoderBytes(bs, d.hh).decodeValue(rv, d.h.fnNoExt(rvType(rv)))
|
|
}
|
|
|
|
func (d *Decoder) fauxUnionReadRawBytes(asString bool) {
|
|
if asString || d.h.RawToString {
|
|
d.n.v = valueTypeString
|
|
// fauxUnion is only used within DecodeNaked calls; consequently, we should try to intern.
|
|
d.n.s = d.stringZC(d.d.DecodeBytes(nil))
|
|
} else {
|
|
d.n.v = valueTypeBytes
|
|
d.n.l = d.d.DecodeBytes([]byte{})
|
|
}
|
|
}
|
|
|
|
// --------------------------------------------------
|
|
|
|
// 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.
|
|
//
|
|
// Note: if IsNil, do not call ElemContainerState.
|
|
type decSliceHelper struct {
|
|
d *Decoder
|
|
ct valueType
|
|
Array bool
|
|
IsNil bool
|
|
}
|
|
|
|
func (d *Decoder) decSliceHelperStart() (x decSliceHelper, clen int) {
|
|
x.ct = d.d.ContainerType()
|
|
x.d = d
|
|
switch x.ct {
|
|
case valueTypeNil:
|
|
x.IsNil = true
|
|
case valueTypeArray:
|
|
x.Array = true
|
|
clen = d.arrayStart()
|
|
case valueTypeMap:
|
|
clen = d.mapStart()
|
|
clen += clen
|
|
default:
|
|
d.errorf("only encoded map or array can be decoded into a slice (%d)", x.ct)
|
|
}
|
|
return
|
|
}
|
|
|
|
func (x decSliceHelper) End() {
|
|
if x.IsNil {
|
|
} else if x.Array {
|
|
x.d.arrayEnd()
|
|
} else {
|
|
x.d.mapEnd()
|
|
}
|
|
}
|
|
|
|
func (x decSliceHelper) ElemContainerState(index int) {
|
|
// Note: if isnil, clen=0, so we never call into ElemContainerState
|
|
|
|
if x.Array {
|
|
x.d.arrayElem()
|
|
} else if index&1 == 0 { // index%2 == 0 {
|
|
x.d.mapElemKey()
|
|
} else {
|
|
x.d.mapElemValue()
|
|
}
|
|
}
|
|
|
|
// isDecodeable checks if value can be decoded into
|
|
//
|
|
// 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)
|
|
func isDecodeable(rv reflect.Value) (canDecode bool) {
|
|
switch rv.Kind() {
|
|
case reflect.Array:
|
|
canDecode = rv.CanAddr()
|
|
case reflect.Ptr, reflect.Slice, reflect.Chan, reflect.Map:
|
|
if !rvIsNil(rv) {
|
|
canDecode = true
|
|
}
|
|
}
|
|
return
|
|
}
|
|
|
|
func decByteSlice(r *decRd, 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 {
|
|
var len2 int
|
|
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
|
|
}
|
|
|
|
// 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) {
|
|
const maxLenIfUnset = 8 // 64
|
|
// handle when maxlen is not set i.e. <= 0
|
|
|
|
// clen==0: use 0
|
|
// maxlen<=0, clen<0: use default
|
|
// maxlen> 0, clen<0: use default
|
|
// maxlen<=0, clen>0: infer maxlen, and cap on it
|
|
// maxlen> 0, clen>0: cap at maxlen
|
|
|
|
if clen == 0 || clen == containerLenNil {
|
|
return
|
|
}
|
|
if clen < 0 {
|
|
return maxLenIfUnset
|
|
}
|
|
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 maxlen > maxLenIfUnset {
|
|
// maxlen = maxLenIfUnset
|
|
// }
|
|
}
|
|
if clen > maxlen {
|
|
rvlen = maxlen
|
|
} else {
|
|
rvlen = clen
|
|
}
|
|
return
|
|
}
|
|
|
|
func decArrayCannotExpand(slh decSliceHelper, hasLen bool, lenv, j, containerLenS int) {
|
|
slh.d.arrayCannotExpand(lenv, j+1)
|
|
// drain completely and return
|
|
slh.ElemContainerState(j)
|
|
slh.d.swallow()
|
|
j++
|
|
for ; slh.d.mapNext(j, containerLenS, hasLen); j++ {
|
|
slh.ElemContainerState(j)
|
|
slh.d.swallow()
|
|
}
|
|
slh.End()
|
|
}
|