--- /dev/null
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Delete the next line to include in the gob package.
+// +build ignore
+
+package gob
+
+// This file is not normally included in the gob package. Used only for debugging the package itself.
+// Except for reading uints, it is an implementation of a reader that is independent of
+// the one implemented by Decoder.
+// To enable the Debug function, delete the +build ignore line above and do
+// go install
+
+import (
+ "bytes"
+ "fmt"
+ "io"
+ "os"
+ "strings"
+ "sync"
+)
+
+var dumpBytes = false // If true, print the remaining bytes in the input buffer at each item.
+
+// Init installs the debugging facility. If this file is not compiled in the
+// package, the tests in codec_test.go are no-ops.
+func init() {
+ debugFunc = Debug
+}
+
+var (
+ blanks = bytes.Repeat([]byte{' '}, 3*10)
+ empty = []byte(": <empty>\n")
+ tabs = strings.Repeat("\t", 100)
+)
+
+// tab indents itself when printed.
+type tab int
+
+func (t tab) String() string {
+ n := int(t)
+ if n > len(tabs) {
+ n = len(tabs)
+ }
+ return tabs[0:n]
+}
+
+func (t tab) print() {
+ fmt.Fprint(os.Stderr, t)
+}
+
+// A peekReader wraps an io.Reader, allowing one to peek ahead to see
+// what's coming without stealing the data from the client of the Reader.
+type peekReader struct {
+ r io.Reader
+ data []byte // read-ahead data
+}
+
+// newPeekReader returns a peekReader that wraps r.
+func newPeekReader(r io.Reader) *peekReader {
+ return &peekReader{r: r}
+}
+
+// Read is the usual method. It will first take data that has been read ahead.
+func (p *peekReader) Read(b []byte) (n int, err error) {
+ if len(p.data) == 0 {
+ return p.r.Read(b)
+ }
+ // Satisfy what's possible from the read-ahead data.
+ n = copy(b, p.data)
+ // Move data down to beginning of slice, to avoid endless growth
+ copy(p.data, p.data[n:])
+ p.data = p.data[:len(p.data)-n]
+ return
+}
+
+// peek returns as many bytes as possible from the unread
+// portion of the stream, up to the length of b.
+func (p *peekReader) peek(b []byte) (n int, err error) {
+ if len(p.data) > 0 {
+ n = copy(b, p.data)
+ if n == len(b) {
+ return
+ }
+ b = b[n:]
+ }
+ if len(b) == 0 {
+ return
+ }
+ m, e := io.ReadFull(p.r, b)
+ if m > 0 {
+ p.data = append(p.data, b[:m]...)
+ }
+ n += m
+ if e == io.ErrUnexpectedEOF {
+ // That means m > 0 but we reached EOF. If we got data
+ // we won't complain about not being able to peek enough.
+ if n > 0 {
+ e = nil
+ } else {
+ e = io.EOF
+ }
+ }
+ return n, e
+}
+
+type debugger struct {
+ mutex sync.Mutex
+ remain int // the number of bytes known to remain in the input
+ remainingKnown bool // the value of 'remain' is valid
+ r *peekReader
+ wireType map[typeId]*wireType
+ tmp []byte // scratch space for decoding uints.
+}
+
+// dump prints the next nBytes of the input.
+// It arranges to print the output aligned from call to
+// call, to make it easy to see what has been consumed.
+func (deb *debugger) dump(format string, args ...interface{}) {
+ if !dumpBytes {
+ return
+ }
+ fmt.Fprintf(os.Stderr, format+" ", args...)
+ if !deb.remainingKnown {
+ return
+ }
+ if deb.remain < 0 {
+ fmt.Fprintf(os.Stderr, "remaining byte count is negative! %d\n", deb.remain)
+ return
+ }
+ data := make([]byte, deb.remain)
+ n, _ := deb.r.peek(data)
+ if n == 0 {
+ os.Stderr.Write(empty)
+ return
+ }
+ b := new(bytes.Buffer)
+ fmt.Fprintf(b, "[%d]{\n", deb.remain)
+ // Blanks until first byte
+ lineLength := 0
+ if n := len(data); n%10 != 0 {
+ lineLength = 10 - n%10
+ fmt.Fprintf(b, "\t%s", blanks[:lineLength*3])
+ }
+ // 10 bytes per line
+ for len(data) > 0 {
+ if lineLength == 0 {
+ fmt.Fprint(b, "\t")
+ }
+ m := 10 - lineLength
+ lineLength = 0
+ if m > len(data) {
+ m = len(data)
+ }
+ fmt.Fprintf(b, "% x\n", data[:m])
+ data = data[m:]
+ }
+ fmt.Fprint(b, "}\n")
+ os.Stderr.Write(b.Bytes())
+}
+
+// Debug prints a human-readable representation of the gob data read from r.
+// It is a no-op unless debugging was enabled when the package was built.
+func Debug(r io.Reader) {
+ err := debug(r)
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "gob debug: %s\n", err)
+ }
+}
+
+// debug implements Debug, but catches panics and returns
+// them as errors to be printed by Debug.
+func debug(r io.Reader) (err error) {
+ defer catchError(&err)
+ fmt.Fprintln(os.Stderr, "Start of debugging")
+ deb := &debugger{
+ r: newPeekReader(r),
+ wireType: make(map[typeId]*wireType),
+ tmp: make([]byte, 16),
+ }
+ if b, ok := r.(*bytes.Buffer); ok {
+ deb.remain = b.Len()
+ deb.remainingKnown = true
+ }
+ deb.gobStream()
+ return
+}
+
+// note that we've consumed some bytes
+func (deb *debugger) consumed(n int) {
+ if deb.remainingKnown {
+ deb.remain -= n
+ }
+}
+
+// int64 decodes and returns the next integer, which must be present.
+// Don't call this if you could be at EOF.
+func (deb *debugger) int64() int64 {
+ return toInt(deb.uint64())
+}
+
+// uint64 returns and decodes the next unsigned integer, which must be present.
+// Don't call this if you could be at EOF.
+// TODO: handle errors better.
+func (deb *debugger) uint64() uint64 {
+ n, w, err := decodeUintReader(deb.r, deb.tmp)
+ if err != nil {
+ errorf("debug: read error: %s", err)
+ }
+ deb.consumed(w)
+ return n
+}
+
+// GobStream:
+// DelimitedMessage* (until EOF)
+func (deb *debugger) gobStream() {
+ // Make sure we're single-threaded through here.
+ deb.mutex.Lock()
+ defer deb.mutex.Unlock()
+
+ for deb.delimitedMessage(0) {
+ }
+}
+
+// DelimitedMessage:
+// uint(lengthOfMessage) Message
+func (deb *debugger) delimitedMessage(indent tab) bool {
+ for {
+ n := deb.loadBlock(true)
+ if n < 0 {
+ return false
+ }
+ deb.dump("Delimited message of length %d", n)
+ deb.message(indent)
+ }
+ return true
+}
+
+// loadBlock preps us to read a message
+// of the length specified next in the input. It returns
+// the length of the block. The argument tells whether
+// an EOF is acceptable now. If it is and one is found,
+// the return value is negative.
+func (deb *debugger) loadBlock(eofOK bool) int {
+ n64, w, err := decodeUintReader(deb.r, deb.tmp) // deb.uint64 will error at EOF
+ if err != nil {
+ if eofOK && err == io.EOF {
+ return -1
+ }
+ errorf("debug: unexpected error: %s", err)
+ }
+ deb.consumed(w)
+ n := int(n64)
+ if n < 0 {
+ errorf("huge value for message length: %d", n64)
+ }
+ return int(n)
+}
+
+// Message:
+// TypeSequence TypedValue
+// TypeSequence
+// (TypeDefinition DelimitedTypeDefinition*)?
+// DelimitedTypeDefinition:
+// uint(lengthOfTypeDefinition) TypeDefinition
+// TypedValue:
+// int(typeId) Value
+func (deb *debugger) message(indent tab) bool {
+ for {
+ // Convert the uint64 to a signed integer typeId
+ uid := deb.int64()
+ id := typeId(uid)
+ deb.dump("type id=%d", id)
+ if id < 0 {
+ deb.typeDefinition(indent, -id)
+ n := deb.loadBlock(false)
+ deb.dump("Message of length %d", n)
+ continue
+ } else {
+ deb.value(indent, id)
+ break
+ }
+ }
+ return true
+}
+
+// Helper methods to make it easy to scan a type descriptor.
+
+// common returns the CommonType at the input point.
+func (deb *debugger) common() CommonType {
+ fieldNum := -1
+ name := ""
+ id := typeId(0)
+ for {
+ delta := deb.delta(-1)
+ if delta == 0 {
+ break
+ }
+ fieldNum += delta
+ switch fieldNum {
+ case 0:
+ name = deb.string()
+ case 1:
+ // Id typeId
+ id = deb.typeId()
+ default:
+ errorf("corrupted CommonType")
+ }
+ }
+ return CommonType{name, id}
+}
+
+// uint returns the unsigned int at the input point, as a uint (not uint64).
+func (deb *debugger) uint() uint {
+ return uint(deb.uint64())
+}
+
+// int returns the signed int at the input point, as an int (not int64).
+func (deb *debugger) int() int {
+ return int(deb.int64())
+}
+
+// typeId returns the type id at the input point.
+func (deb *debugger) typeId() typeId {
+ return typeId(deb.int64())
+}
+
+// string returns the string at the input point.
+func (deb *debugger) string() string {
+ x := int(deb.uint64())
+ b := make([]byte, x)
+ nb, _ := deb.r.Read(b)
+ if nb != x {
+ errorf("corrupted type")
+ }
+ deb.consumed(nb)
+ return string(b)
+}
+
+// delta returns the field delta at the input point. The expect argument,
+// if non-negative, identifies what the value should be.
+func (deb *debugger) delta(expect int) int {
+ delta := int(deb.uint64())
+ if delta < 0 || (expect >= 0 && delta != expect) {
+ errorf("decode: corrupted type: delta %d expected %d", delta, expect)
+ }
+ return delta
+}
+
+// TypeDefinition:
+// [int(-typeId) (already read)] encodingOfWireType
+func (deb *debugger) typeDefinition(indent tab, id typeId) {
+ deb.dump("type definition for id %d", id)
+ // Encoding is of a wireType. Decode the structure as usual
+ fieldNum := -1
+ wire := new(wireType)
+ // A wireType defines a single field.
+ delta := deb.delta(-1)
+ fieldNum += delta
+ switch fieldNum {
+ case 0: // array type, one field of {{Common}, elem, length}
+ // Field number 0 is CommonType
+ deb.delta(1)
+ com := deb.common()
+ // Field number 1 is type Id of elem
+ deb.delta(1)
+ id := deb.typeId()
+ // Field number 3 is length
+ deb.delta(1)
+ length := deb.int()
+ wire.ArrayT = &arrayType{com, id, length}
+
+ case 1: // slice type, one field of {{Common}, elem}
+ // Field number 0 is CommonType
+ deb.delta(1)
+ com := deb.common()
+ // Field number 1 is type Id of elem
+ deb.delta(1)
+ id := deb.typeId()
+ wire.SliceT = &sliceType{com, id}
+
+ case 2: // struct type, one field of {{Common}, []fieldType}
+ // Field number 0 is CommonType
+ deb.delta(1)
+ com := deb.common()
+ // Field number 1 is slice of FieldType
+ deb.delta(1)
+ numField := int(deb.uint())
+ field := make([]*fieldType, numField)
+ for i := 0; i < numField; i++ {
+ field[i] = new(fieldType)
+ deb.delta(1) // field 0 of fieldType: name
+ field[i].Name = deb.string()
+ deb.delta(1) // field 1 of fieldType: id
+ field[i].Id = deb.typeId()
+ deb.delta(0) // end of fieldType
+ }
+ wire.StructT = &structType{com, field}
+
+ case 3: // map type, one field of {{Common}, key, elem}
+ // Field number 0 is CommonType
+ deb.delta(1)
+ com := deb.common()
+ // Field number 1 is type Id of key
+ deb.delta(1)
+ keyId := deb.typeId()
+ // Field number 2 is type Id of elem
+ deb.delta(1)
+ elemId := deb.typeId()
+ wire.MapT = &mapType{com, keyId, elemId}
+ case 4: // GobEncoder type, one field of {{Common}}
+ // Field number 0 is CommonType
+ deb.delta(1)
+ com := deb.common()
+ wire.GobEncoderT = &gobEncoderType{com}
+ default:
+ errorf("bad field in type %d", fieldNum)
+ }
+ deb.printWireType(indent, wire)
+ deb.delta(0) // end inner type (arrayType, etc.)
+ deb.delta(0) // end wireType
+ // Remember we've seen this type.
+ deb.wireType[id] = wire
+}
+
+// Value:
+// SingletonValue | StructValue
+func (deb *debugger) value(indent tab, id typeId) {
+ wire, ok := deb.wireType[id]
+ if ok && wire.StructT != nil {
+ deb.structValue(indent, id)
+ } else {
+ deb.singletonValue(indent, id)
+ }
+}
+
+// SingletonValue:
+// uint(0) FieldValue
+func (deb *debugger) singletonValue(indent tab, id typeId) {
+ deb.dump("Singleton value")
+ // is it a builtin type?
+ wire := deb.wireType[id]
+ _, ok := builtinIdToType[id]
+ if !ok && wire == nil {
+ errorf("type id %d not defined", id)
+ }
+ m := deb.uint64()
+ if m != 0 {
+ errorf("expected zero; got %d", m)
+ }
+ deb.fieldValue(indent, id)
+}
+
+// InterfaceValue:
+// NilInterfaceValue | NonNilInterfaceValue
+func (deb *debugger) interfaceValue(indent tab) {
+ deb.dump("Start of interface value")
+ if nameLen := deb.uint64(); nameLen == 0 {
+ deb.nilInterfaceValue(indent)
+ } else {
+ deb.nonNilInterfaceValue(indent, int(nameLen))
+ }
+}
+
+// NilInterfaceValue:
+// uint(0) [already read]
+func (deb *debugger) nilInterfaceValue(indent tab) int {
+ fmt.Fprintf(os.Stderr, "%snil interface\n", indent)
+ return 0
+}
+
+// NonNilInterfaceValue:
+// ConcreteTypeName TypeSequence InterfaceContents
+// ConcreteTypeName:
+// uint(lengthOfName) [already read=n] name
+// InterfaceContents:
+// int(concreteTypeId) DelimitedValue
+// DelimitedValue:
+// uint(length) Value
+func (deb *debugger) nonNilInterfaceValue(indent tab, nameLen int) {
+ // ConcreteTypeName
+ b := make([]byte, nameLen)
+ deb.r.Read(b) // TODO: CHECK THESE READS!!
+ deb.consumed(nameLen)
+ name := string(b)
+
+ for {
+ id := deb.typeId()
+ if id < 0 {
+ deb.typeDefinition(indent, -id)
+ n := deb.loadBlock(false)
+ deb.dump("Nested message of length %d", n)
+ } else {
+ // DelimitedValue
+ x := deb.uint64() // in case we want to ignore the value; we don't.
+ fmt.Fprintf(os.Stderr, "%sinterface value, type %q id=%d; valueLength %d\n", indent, name, id, x)
+ deb.value(indent, id)
+ break
+ }
+ }
+}
+
+// printCommonType prints a common type; used by printWireType.
+func (deb *debugger) printCommonType(indent tab, kind string, common *CommonType) {
+ indent.print()
+ fmt.Fprintf(os.Stderr, "%s %q id=%d\n", kind, common.Name, common.Id)
+}
+
+// printWireType prints the contents of a wireType.
+func (deb *debugger) printWireType(indent tab, wire *wireType) {
+ fmt.Fprintf(os.Stderr, "%stype definition {\n", indent)
+ indent++
+ switch {
+ case wire.ArrayT != nil:
+ deb.printCommonType(indent, "array", &wire.ArrayT.CommonType)
+ fmt.Fprintf(os.Stderr, "%slen %d\n", indent+1, wire.ArrayT.Len)
+ fmt.Fprintf(os.Stderr, "%selemid %d\n", indent+1, wire.ArrayT.Elem)
+ case wire.MapT != nil:
+ deb.printCommonType(indent, "map", &wire.MapT.CommonType)
+ fmt.Fprintf(os.Stderr, "%skey id=%d\n", indent+1, wire.MapT.Key)
+ fmt.Fprintf(os.Stderr, "%selem id=%d\n", indent+1, wire.MapT.Elem)
+ case wire.SliceT != nil:
+ deb.printCommonType(indent, "slice", &wire.SliceT.CommonType)
+ fmt.Fprintf(os.Stderr, "%selem id=%d\n", indent+1, wire.SliceT.Elem)
+ case wire.StructT != nil:
+ deb.printCommonType(indent, "struct", &wire.StructT.CommonType)
+ for i, field := range wire.StructT.Field {
+ fmt.Fprintf(os.Stderr, "%sfield %d:\t%s\tid=%d\n", indent+1, i, field.Name, field.Id)
+ }
+ case wire.GobEncoderT != nil:
+ deb.printCommonType(indent, "GobEncoder", &wire.GobEncoderT.CommonType)
+ }
+ indent--
+ fmt.Fprintf(os.Stderr, "%s}\n", indent)
+}
+
+// fieldValue prints a value of any type, such as a struct field.
+// FieldValue:
+// builtinValue | ArrayValue | MapValue | SliceValue | StructValue | InterfaceValue
+func (deb *debugger) fieldValue(indent tab, id typeId) {
+ _, ok := builtinIdToType[id]
+ if ok {
+ if id == tInterface {
+ deb.interfaceValue(indent)
+ } else {
+ deb.printBuiltin(indent, id)
+ }
+ return
+ }
+ wire, ok := deb.wireType[id]
+ if !ok {
+ errorf("type id %d not defined", id)
+ }
+ switch {
+ case wire.ArrayT != nil:
+ deb.arrayValue(indent, wire)
+ case wire.MapT != nil:
+ deb.mapValue(indent, wire)
+ case wire.SliceT != nil:
+ deb.sliceValue(indent, wire)
+ case wire.StructT != nil:
+ deb.structValue(indent, id)
+ case wire.GobEncoderT != nil:
+ deb.gobEncoderValue(indent, id)
+ default:
+ panic("bad wire type for field")
+ }
+}
+
+// printBuiltin prints a value not of a fundamental type, that is,
+// one whose type is known to gobs at bootstrap time.
+func (deb *debugger) printBuiltin(indent tab, id typeId) {
+ switch id {
+ case tBool:
+ x := deb.int64()
+ if x == 0 {
+ fmt.Fprintf(os.Stderr, "%sfalse\n", indent)
+ } else {
+ fmt.Fprintf(os.Stderr, "%strue\n", indent)
+ }
+ case tInt:
+ x := deb.int64()
+ fmt.Fprintf(os.Stderr, "%s%d\n", indent, x)
+ case tUint:
+ x := deb.int64()
+ fmt.Fprintf(os.Stderr, "%s%d\n", indent, x)
+ case tFloat:
+ x := deb.uint64()
+ fmt.Fprintf(os.Stderr, "%s%g\n", indent, floatFromBits(x))
+ case tComplex:
+ r := deb.uint64()
+ i := deb.uint64()
+ fmt.Fprintf(os.Stderr, "%s%g+%gi\n", indent, floatFromBits(r), floatFromBits(i))
+ case tBytes:
+ x := int(deb.uint64())
+ b := make([]byte, x)
+ deb.r.Read(b)
+ deb.consumed(x)
+ fmt.Fprintf(os.Stderr, "%s{% x}=%q\n", indent, b, b)
+ case tString:
+ x := int(deb.uint64())
+ b := make([]byte, x)
+ deb.r.Read(b)
+ deb.consumed(x)
+ fmt.Fprintf(os.Stderr, "%s%q\n", indent, b)
+ default:
+ panic("unknown builtin")
+ }
+}
+
+// ArrayValue:
+// uint(n) FieldValue*n
+func (deb *debugger) arrayValue(indent tab, wire *wireType) {
+ elemId := wire.ArrayT.Elem
+ u := deb.uint64()
+ length := int(u)
+ for i := 0; i < length; i++ {
+ deb.fieldValue(indent, elemId)
+ }
+ if length != wire.ArrayT.Len {
+ fmt.Fprintf(os.Stderr, "%s(wrong length for array: %d should be %d)\n", indent, length, wire.ArrayT.Len)
+ }
+}
+
+// MapValue:
+// uint(n) (FieldValue FieldValue)*n [n (key, value) pairs]
+func (deb *debugger) mapValue(indent tab, wire *wireType) {
+ keyId := wire.MapT.Key
+ elemId := wire.MapT.Elem
+ u := deb.uint64()
+ length := int(u)
+ for i := 0; i < length; i++ {
+ deb.fieldValue(indent+1, keyId)
+ deb.fieldValue(indent+1, elemId)
+ }
+}
+
+// SliceValue:
+// uint(n) (n FieldValue)
+func (deb *debugger) sliceValue(indent tab, wire *wireType) {
+ elemId := wire.SliceT.Elem
+ u := deb.uint64()
+ length := int(u)
+ deb.dump("Start of slice of length %d", length)
+
+ for i := 0; i < length; i++ {
+ deb.fieldValue(indent, elemId)
+ }
+}
+
+// StructValue:
+// (uint(fieldDelta) FieldValue)*
+func (deb *debugger) structValue(indent tab, id typeId) {
+ deb.dump("Start of struct value of %q id=%d\n<<\n", id.name(), id)
+ fmt.Fprintf(os.Stderr, "%s%s struct {\n", indent, id.name())
+ wire, ok := deb.wireType[id]
+ if !ok {
+ errorf("type id %d not defined", id)
+ }
+ strct := wire.StructT
+ fieldNum := -1
+ indent++
+ for {
+ delta := deb.uint64()
+ if delta == 0 { // struct terminator is zero delta fieldnum
+ break
+ }
+ fieldNum += int(delta)
+ if fieldNum < 0 || fieldNum >= len(strct.Field) {
+ deb.dump("field number out of range: prevField=%d delta=%d", fieldNum-int(delta), delta)
+ break
+ }
+ fmt.Fprintf(os.Stderr, "%sfield %d:\t%s\n", indent, fieldNum, wire.StructT.Field[fieldNum].Name)
+ deb.fieldValue(indent+1, strct.Field[fieldNum].Id)
+ }
+ indent--
+ fmt.Fprintf(os.Stderr, "%s} // end %s struct\n", indent, id.name())
+ deb.dump(">> End of struct value of type %d %q", id, id.name())
+}
+
+// GobEncoderValue:
+// uint(n) byte*n
+func (deb *debugger) gobEncoderValue(indent tab, id typeId) {
+ len := deb.uint64()
+ deb.dump("GobEncoder value of %q id=%d, length %d\n", id.name(), id, len)
+ fmt.Fprintf(os.Stderr, "%s%s (implements GobEncoder)\n", indent, id.name())
+ data := make([]byte, len)
+ _, err := deb.r.Read(data)
+ if err != nil {
+ errorf("gobEncoder data read: %s", err)
+ }
+ fmt.Fprintf(os.Stderr, "%s[% .2x]\n", indent+1, data)
+}
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