mirror of
https://github.com/golang/go
synced 2024-11-22 00:54:43 -07:00
gob: better debugging, commentary
Re-implement the debugging helper to be independent of the existing implementation. This is preparatory to a rewrite to clean up issue 1416. Include a definition of the grammar of the data stream. R=rsc CC=golang-dev https://golang.org/cl/3970045
This commit is contained in:
Rob Pike
parent
5cf120827c
commit
5b5a674b46
@ -1307,6 +1307,31 @@ func TestUnexportedFields(t *testing.T) {
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}
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}
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var singletons = []interface{}{
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true,
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7,
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3.2,
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"hello",
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[3]int{11, 22, 33},
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[]float32{0.5, 0.25, 0.125},
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map[string]int{"one": 1, "two": 2},
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}
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func TestDebugSingleton(t *testing.T) {
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if debugFunc == nil {
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return
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}
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b := new(bytes.Buffer)
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// Accumulate a number of values and print them out all at once.
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for _, x := range singletons {
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err := NewEncoder(b).Encode(x)
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if err != nil {
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t.Fatal("encode:", err)
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}
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}
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debugFunc(b)
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}
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// A type that won't be defined in the gob until we send it in an interface value.
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type OnTheFly struct {
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A int
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@ -1325,7 +1350,7 @@ type DT struct {
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S []string
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}
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func TestDebug(t *testing.T) {
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func TestDebugStruct(t *testing.T) {
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if debugFunc == nil {
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return
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}
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@ -2,309 +2,683 @@ package gob
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// This file is not normally included in the gob package. Used only for debugging the package itself.
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// Add debug.go to the files listed in the Makefile to add Debug to the gob package.
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// Except for reading uints, it is an implementation of a reader that is independent of
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// the one implemented by Decoder.
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import (
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"bytes"
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"fmt"
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"io"
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"os"
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"reflect"
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"runtime"
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"strings"
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"sync"
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)
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var dump = false // If true, print the remaining bytes in the input buffer at each item.
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var dumpBytes = false // If true, print the remaining bytes in the input buffer at each item.
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// Init installs the debugging facility. If this file is not compiled in the
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// package, the test in codec_test.go is a no-op.
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// package, the tests in codec_test.go are no-ops.
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func init() {
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debugFunc = Debug
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}
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var (
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blanks = bytes.Repeat([]byte{' '}, 3*10)
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empty = []byte(": <empty>\n")
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tabs = strings.Repeat("\t", 100)
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)
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// tab indents itself when printed.
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type tab int
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func (t tab) String() string {
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n := int(t)
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if n > len(tabs) {
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n = len(tabs)
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}
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return tabs[0:n]
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}
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func (t tab) print() {
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fmt.Fprint(os.Stderr, t)
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}
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// A peekReader wraps an io.Reader, allowing one to peek ahead to see
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// what's coming without stealing the data from the client of the Reader.
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type peekReader struct {
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r io.Reader
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data []byte // read-ahead data
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}
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// newPeekReader returns a peekReader that wraps r.
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func newPeekReader(r io.Reader) *peekReader {
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return &peekReader{r: r}
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}
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// Read is the usual method. It will first take data that has been read ahead.
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func (p *peekReader) Read(b []byte) (n int, err os.Error) {
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if len(p.data) == 0 {
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return p.r.Read(b)
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}
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// Satisfy what's possible from the read-ahead data.
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n = copy(b, p.data)
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// Move data down to beginning of slice, to avoid endless growth
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copy(p.data, p.data[n:])
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p.data = p.data[:len(p.data)-n]
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return
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}
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// peek returns as many bytes as possible from the unread
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// portion of the stream, up to the length of b.
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func (p *peekReader) peek(b []byte) (n int, err os.Error) {
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if len(p.data) > 0 {
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n = copy(b, p.data)
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if n == len(b) {
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return
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}
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b = b[n:]
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}
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if len(b) == 0 {
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return
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}
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m, e := io.ReadFull(p.r, b)
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if m > 0 {
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p.data = append(p.data, b[:m]...)
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}
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n += m
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if e == io.ErrUnexpectedEOF {
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// That means m > 0 but we reached EOF. If we got data
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// we won't complain about not being able to peek enough.
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if n > 0 {
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e = nil
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} else {
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e = os.EOF
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}
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}
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return n, e
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}
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// dump prints the next nBytes of the input.
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// It arranges to print the output aligned from call to
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// call, to make it easy to see what has been consumed.
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func (deb *debugger) dump(nBytes int, format string, args ...interface{}) {
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if !dumpBytes {
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return
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}
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fmt.Fprintf(os.Stderr, format+" ", args...)
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if nBytes < 0 {
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fmt.Fprintf(os.Stderr, "nbytes is negative! %d\n", nBytes)
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return
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}
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data := make([]byte, nBytes)
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n, _ := deb.r.peek(data)
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if n == 0 {
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os.Stderr.Write(empty)
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return
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}
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b := new(bytes.Buffer)
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fmt.Fprint(b, "{\n")
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// Blanks until first byte
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lineLength := 0
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if n := len(data); n%10 != 0 {
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lineLength = 10 - n%10
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fmt.Fprintf(b, "\t%s", blanks[:lineLength*3])
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}
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// 10 bytes per line
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for len(data) > 0 {
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if lineLength == 0 {
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fmt.Fprint(b, "\t")
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}
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m := 10 - lineLength
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lineLength = 0
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if m > len(data) {
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m = len(data)
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}
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fmt.Fprintf(b, "% x\n", data[:m])
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data = data[m:]
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}
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fmt.Fprint(b, "}\n")
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os.Stderr.Write(b.Bytes())
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}
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type debugger struct {
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mutex sync.Mutex
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r *peekReader
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wireType map[typeId]*wireType
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tmp []byte // scratch space for decoding uints.
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}
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// Debug prints a human-readable representation of the gob data read from r.
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func Debug(r io.Reader) {
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defer func() {
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if e := recover(); e != nil {
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if _, ok := e.(runtime.Error); ok {
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panic(e)
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}
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fmt.Printf("error during debugging: %v\n", e)
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}
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}()
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NewDecoder(r).debug()
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fmt.Fprintln(os.Stderr, "Start of debugging")
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deb := &debugger{
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r: newPeekReader(r),
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wireType: make(map[typeId]*wireType),
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tmp: make([]byte, 16),
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}
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deb.gobStream()
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}
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// debugRecv is like recv but prints what it sees.
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func (dec *Decoder) debugRecv() {
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if dec.byteBuffer != nil && dec.byteBuffer.Len() != 0 {
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fmt.Printf("error in recv: %d bytes left in input buffer\n", dec.byteBuffer.Len())
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return
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}
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// Read a count.
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var nbytes uint64
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nbytes, dec.err = decodeUintReader(dec.r, dec.countBuf[0:])
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if dec.err != nil {
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fmt.Printf("receiver error on count: %s\n", dec.err)
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return
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}
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// Allocate the buffer.
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if nbytes > uint64(len(dec.buf)) {
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dec.buf = make([]byte, nbytes+1000)
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}
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dec.byteBuffer = bytes.NewBuffer(dec.buf[0:nbytes])
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// Read the data
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_, dec.err = io.ReadFull(dec.r, dec.buf[0:nbytes])
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if dec.err != nil {
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fmt.Printf("receiver error on data: %s\n", dec.err)
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if dec.err == os.EOF {
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dec.err = io.ErrUnexpectedEOF
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}
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return
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}
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if dump {
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fmt.Printf("received %d bytes:\n\t% x\n", nbytes, dec.byteBuffer.Bytes())
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// toInt turns an encoded uint64 into an int, according to the marshaling rules.
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func toInt(x uint64) int64 {
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i := int64(x >> 1)
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if x&1 != 0 {
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i = ^i
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}
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return i
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}
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// readInt returns the next int, which must be present,
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// and the number of bytes it consumed.
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// Don't call this if you could be at EOF.
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func (deb *debugger) readInt() (i int64, w int) {
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var u uint64
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u, w = deb.readUint()
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return toInt(u), w
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}
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// debug is like Decode but just prints what it finds. It should be safe even for corrupted data.
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func (dec *Decoder) debug() {
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// readUint returns the next uint, which must be present.
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// and the number of bytes it consumed.
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// Don't call this if you could be at EOF.
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// TODO: handle errors better.
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func (deb *debugger) readUint() (x uint64, w int) {
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n, w, err := decodeUintReader(deb.r, deb.tmp)
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if err != nil {
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errorf("debug: read error: %s", err)
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}
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return n, w
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}
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// GobStream:
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// DelimitedMessage* (until EOF)
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func (deb *debugger) gobStream() {
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// Make sure we're single-threaded through here.
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dec.mutex.Lock()
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defer dec.mutex.Unlock()
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deb.mutex.Lock()
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defer deb.mutex.Unlock()
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dec.err = nil
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dec.debugRecv()
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if dec.err != nil {
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return
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for deb.delimitedMessage(0) {
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}
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dec.debugFromBuffer(0, false)
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}
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// printFromBuffer prints the next value. The buffer contains data, but it may
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// be a type descriptor and we may need to load more data to see the value;
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// printType takes care of that.
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func (dec *Decoder) debugFromBuffer(indent int, countPresent bool) {
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for dec.state.b.Len() > 0 {
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// Receive a type id.
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id := typeId(dec.state.decodeInt())
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// Is it a new type?
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if id < 0 { // 0 is the error state, handled above
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// If the id is negative, we have a type.
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dec.debugRecvType(-id)
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if dec.err != nil {
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break
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}
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continue
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// DelimitedMessage:
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// uint(lengthOfMessage) Message
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func (deb *debugger) delimitedMessage(indent tab) bool {
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for {
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n := deb.loadBlock(true)
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if n < 0 {
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return false
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}
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deb.dump(int(n), "Message of length %d", n)
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deb.message(indent, n)
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}
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return true
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}
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// No, it's a value.
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// Make sure the type has been defined already or is a builtin type (for
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// top-level singleton values).
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if dec.wireType[id] == nil && builtinIdToType[id] == nil {
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dec.err = errBadType
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// loadBlock preps us to read a message
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// of the length specified next in the input. It returns
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// the length of the block. The argument tells whether
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// an EOF is acceptable now. If it is and one is found,
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// the return value is negative.
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func (deb *debugger) loadBlock(eofOK bool) int {
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n64, _, err := decodeUintReader(deb.r, deb.tmp)
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if err != nil {
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if eofOK && err == os.EOF {
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return -1
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}
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errorf("debug: unexpected error: %s", err)
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}
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n := int(n64)
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if n < 0 {
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errorf("huge value for message length: %d", n64)
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}
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return n
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}
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// Message:
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// TypeSequence TypedValue
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// TypeSequence
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// (TypeDefinition DelimitedTypeDefinition*)?
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// DelimitedTypeDefinition:
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// uint(lengthOfTypeDefinition) TypeDefinition
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// TypedValue:
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// int(typeId) Value
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func (deb *debugger) message(indent tab, n int) bool {
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for {
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// Convert the uint64 to a signed integer typeId
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uid, w := deb.readInt()
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id := typeId(uid)
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n -= w
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deb.dump(n, "type id=%d", id)
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if id < 0 {
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n -= deb.typeDefinition(indent, -id, n)
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n = deb.loadBlock(false)
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deb.dump(n, "Message of length %d", n)
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continue
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} else {
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deb.value(indent, id, n)
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break
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}
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if countPresent {
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dec.state.decodeUint()
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}
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dec.debugPrint(indent, id)
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break
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}
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return true
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}
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func (dec *Decoder) debugRecvType(id typeId) {
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// Have we already seen this type? That's an error
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if _, alreadySeen := dec.wireType[id]; alreadySeen {
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dec.err = os.ErrorString("gob: duplicate type received")
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return
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// TypeDefinition:
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// [int(-typeId) (already read)] encodingOfWireType
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func (deb *debugger) typeDefinition(indent tab, id typeId, n int) int {
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deb.dump(n, "type definition for id %d", id)
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// Encoding is of a wireType. Decode the structure as usual
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fieldNum := -1
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m := 0
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// Closures to make it easy to scan.
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// Read a uint from the input
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getUint := func() uint {
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i, w := deb.readUint()
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m += w
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n -= w
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return uint(i)
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}
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// Read an int from the input
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getInt := func() int {
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i, w := deb.readInt()
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m += w
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n -= w
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return int(i)
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}
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// Read a string from the input
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getString := func() string {
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u, w := deb.readUint()
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x := int(u)
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m += w
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n -= w
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b := make([]byte, x)
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nb, _ := deb.r.Read(b)
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if nb != x {
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errorf("corrupted type")
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}
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m += x
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n -= x
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return string(b)
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}
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// Read a typeId from the input
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getTypeId := func() typeId {
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return typeId(getInt())
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}
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// Read a delta from the input.
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getDelta := func(expect int) int {
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u, w := deb.readUint()
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m += w
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n -= w
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delta := int(u)
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if delta < 0 || (expect >= 0 && delta != expect) {
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errorf("gob decode: corrupted type: delta %d expected %d", delta, expect)
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}
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return int(u)
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}
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// Read a CommonType from the input
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common := func() CommonType {
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fieldNum := -1
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name := ""
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id := typeId(0)
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for {
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delta := getDelta(-1)
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if delta == 0 {
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break
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}
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fieldNum += delta
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switch fieldNum {
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case 0:
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name = getString()
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case 1:
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// Id typeId
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id = getTypeId()
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default:
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errorf("corrupted CommonType")
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}
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}
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return CommonType{name, id}
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}
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// Type:
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wire := new(wireType)
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dec.err = dec.decode(tWireType, reflect.NewValue(wire))
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if dec.err == nil {
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printWireType(wire)
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}
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// Remember we've seen this type.
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dec.wireType[id] = wire
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// A wireType defines a single field.
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delta := getDelta(-1)
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fieldNum += delta
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switch fieldNum {
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case 0: // array type, one field of {{Common}, elem, length}
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// Field number 0 is CommonType
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getDelta(1)
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com := common()
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// Field number 1 is type Id of elem
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getDelta(1)
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id := getTypeId()
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// Field number 3 is length
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getDelta(1)
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length := getInt()
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wire.ArrayT = &arrayType{com, id, length}
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// Load the next parcel.
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dec.debugRecv()
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}
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case 1: // slice type, one field of {{Common}, elem}
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// Field number 0 is CommonType
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getDelta(1)
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com := common()
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// Field number 1 is type Id of elem
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getDelta(1)
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id := getTypeId()
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wire.SliceT = &sliceType{com, id}
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func printWireType(wire *wireType) {
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fmt.Printf("type definition {\n")
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switch {
|
||||
case wire.ArrayT != nil:
|
||||
printCommonType("array", &wire.ArrayT.CommonType)
|
||||
fmt.Printf("\tlen %d\n\telemid %d\n", wire.ArrayT.Len, wire.ArrayT.Elem)
|
||||
case wire.MapT != nil:
|
||||
printCommonType("map", &wire.MapT.CommonType)
|
||||
fmt.Printf("\tkeyid %d\n", wire.MapT.Key)
|
||||
fmt.Printf("\telemid %d\n", wire.MapT.Elem)
|
||||
case wire.SliceT != nil:
|
||||
printCommonType("slice", &wire.SliceT.CommonType)
|
||||
fmt.Printf("\telemid %d\n", wire.SliceT.Elem)
|
||||
case wire.StructT != nil:
|
||||
printCommonType("struct", &wire.StructT.CommonType)
|
||||
for i, field := range wire.StructT.Field {
|
||||
fmt.Printf("\tfield %d:\t%s\tid=%d\n", i, field.Name, field.Id)
|
||||
case 2: // struct type, one field of {{Common}, []fieldType}
|
||||
// Field number 0 is CommonType
|
||||
getDelta(1)
|
||||
com := common()
|
||||
// Field number 1 is slice of FieldType
|
||||
getDelta(1)
|
||||
numField := int(getUint())
|
||||
field := make([]*fieldType, numField)
|
||||
for i := 0; i < numField; i++ {
|
||||
field[i] = new(fieldType)
|
||||
getDelta(1) // field 0 of fieldType: name
|
||||
field[i].Name = getString()
|
||||
getDelta(1) // field 1 of fieldType: id
|
||||
field[i].Id = getTypeId()
|
||||
getDelta(0) // end of fieldType
|
||||
}
|
||||
wire.StructT = &structType{com, field}
|
||||
|
||||
case 3: // map type, one field of {{Common}, key, elem}
|
||||
// Field number 0 is CommonType
|
||||
getDelta(1)
|
||||
com := common()
|
||||
// Field number 1 is type Id of key
|
||||
getDelta(1)
|
||||
keyId := getTypeId()
|
||||
wire.SliceT = &sliceType{com, id}
|
||||
// Field number 2 is type Id of elem
|
||||
getDelta(1)
|
||||
elemId := getTypeId()
|
||||
wire.MapT = &mapType{com, keyId, elemId}
|
||||
default:
|
||||
errorf("bad field in type %d", fieldNum)
|
||||
}
|
||||
fmt.Printf("}\n")
|
||||
deb.printWireType(indent, wire)
|
||||
getDelta(0) // end inner type (arrayType, etc.)
|
||||
getDelta(0) // end wireType
|
||||
// Remember we've seen this type.
|
||||
deb.wireType[id] = wire
|
||||
return m
|
||||
}
|
||||
|
||||
func printCommonType(kind string, common *CommonType) {
|
||||
fmt.Printf("\t%s %q\n\tid: %d\n", kind, common.Name, common.Id)
|
||||
|
||||
// Value:
|
||||
// ConcreteValue | InterfaceValue
|
||||
func (deb *debugger) value(indent tab, id typeId, n int) int {
|
||||
if id == tInterface {
|
||||
return deb.interfaceValue(indent, n)
|
||||
}
|
||||
return deb.concreteValue(indent, id, n)
|
||||
}
|
||||
|
||||
func (dec *Decoder) debugPrint(indent int, id typeId) {
|
||||
wire, ok := dec.wireType[id]
|
||||
|
||||
// ConcreteValue:
|
||||
// SingletonValue | StructValue
|
||||
func (deb *debugger) concreteValue(indent tab, id typeId, n int) int {
|
||||
wire, ok := deb.wireType[id]
|
||||
if ok && wire.StructT != nil {
|
||||
dec.debugStruct(indent+1, id, wire)
|
||||
} else {
|
||||
dec.debugSingle(indent+1, id, wire)
|
||||
return deb.structValue(indent, id, n)
|
||||
}
|
||||
return deb.singletonValue(indent, id, n)
|
||||
}
|
||||
|
||||
func (dec *Decoder) debugSingle(indent int, id typeId, wire *wireType) {
|
||||
// SingletonValue:
|
||||
// int(0) FieldValue
|
||||
func (deb *debugger) singletonValue(indent tab, id typeId, n int) int {
|
||||
deb.dump(n, "Singleton value")
|
||||
// is it a builtin type?
|
||||
wire := deb.wireType[id]
|
||||
_, ok := builtinIdToType[id]
|
||||
if !ok && wire == nil {
|
||||
errorf("type id %d not defined\n", id)
|
||||
errorf("type id %d not defined", id)
|
||||
}
|
||||
dec.state.decodeUint()
|
||||
dec.printItem(indent, id)
|
||||
m, w := deb.readInt()
|
||||
if m != 0 {
|
||||
errorf("expected zero; got %d", n)
|
||||
}
|
||||
return w + deb.fieldValue(indent, id, n-w)
|
||||
}
|
||||
|
||||
func (dec *Decoder) printItem(indent int, id typeId) {
|
||||
if dump {
|
||||
fmt.Printf("print item %d bytes: % x\n", dec.state.b.Len(), dec.state.b.Bytes())
|
||||
// InterfaceValue:
|
||||
// NilInterfaceValue | NonNilInterfaceValue
|
||||
func (deb *debugger) interfaceValue(indent tab, n int) int {
|
||||
deb.dump(n, "Start of interface value")
|
||||
nameLen, w := deb.readUint()
|
||||
n -= w
|
||||
if n == 0 {
|
||||
return w + deb.nilInterfaceValue(indent)
|
||||
}
|
||||
return w + deb.nonNilInterfaceValue(indent, int(nameLen), n)
|
||||
}
|
||||
|
||||
// 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, n int) int {
|
||||
// ConcreteTypeName
|
||||
b := make([]byte, nameLen)
|
||||
deb.r.Read(b) // TODO: CHECK THESE READS!!
|
||||
w := nameLen
|
||||
n -= nameLen
|
||||
name := string(b)
|
||||
fmt.Fprintf(os.Stderr, "%sinterface value, type %q length %d\n", indent, name, n)
|
||||
|
||||
for {
|
||||
x, width := deb.readInt()
|
||||
n -= w
|
||||
w += width
|
||||
id := typeId(x)
|
||||
if id < 0 {
|
||||
deb.typeDefinition(indent, -id, n)
|
||||
n = deb.loadBlock(false)
|
||||
deb.dump(n, "Message of length %d", n)
|
||||
} else {
|
||||
// DelimitedValue
|
||||
x, width := deb.readUint() // in case we want to ignore the value; we don't.
|
||||
n -= w
|
||||
w += width
|
||||
fmt.Fprintf(os.Stderr, "%sinterface value, type %q id=%d; length %d\n", indent, name, id, x)
|
||||
ZZ := w + deb.value(indent, id, int(x))
|
||||
return ZZ
|
||||
}
|
||||
}
|
||||
panic("not reached")
|
||||
}
|
||||
|
||||
// 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)
|
||||
}
|
||||
}
|
||||
indent--
|
||||
fmt.Fprintf(os.Stderr, "%s}\n", indent)
|
||||
}
|
||||
|
||||
// fieldValue prints a value of any type, such as a struct field.
|
||||
func (deb *debugger) fieldValue(indent tab, id typeId, n int) int {
|
||||
_, ok := builtinIdToType[id]
|
||||
if ok {
|
||||
dec.printBuiltin(indent, id)
|
||||
return
|
||||
return deb.printBuiltin(indent, id, n)
|
||||
}
|
||||
wire, ok := dec.wireType[id]
|
||||
wire, ok := deb.wireType[id]
|
||||
if !ok {
|
||||
errorf("type id %d not defined\n", id)
|
||||
errorf("type id %d not defined", id)
|
||||
}
|
||||
switch {
|
||||
case wire.ArrayT != nil:
|
||||
dec.printArray(indent, wire)
|
||||
return deb.arrayValue(indent, wire, n)
|
||||
case wire.MapT != nil:
|
||||
dec.printMap(indent, wire)
|
||||
return deb.mapValue(indent, wire, n)
|
||||
case wire.SliceT != nil:
|
||||
dec.printSlice(indent, wire)
|
||||
return deb.sliceValue(indent, wire, n)
|
||||
case wire.StructT != nil:
|
||||
dec.debugStruct(indent, id, wire)
|
||||
return deb.structValue(indent, id, n)
|
||||
}
|
||||
panic("unreached")
|
||||
}
|
||||
|
||||
func (dec *Decoder) printArray(indent int, wire *wireType) {
|
||||
elemId := wire.ArrayT.Elem
|
||||
n := int(dec.state.decodeUint())
|
||||
for i := 0; i < n && dec.err == nil; i++ {
|
||||
dec.printItem(indent, elemId)
|
||||
}
|
||||
if n != wire.ArrayT.Len {
|
||||
tab(indent)
|
||||
fmt.Printf("(wrong length for array: %d should be %d)\n", n, wire.ArrayT.Len)
|
||||
}
|
||||
}
|
||||
|
||||
func (dec *Decoder) printMap(indent int, wire *wireType) {
|
||||
keyId := wire.MapT.Key
|
||||
elemId := wire.MapT.Elem
|
||||
n := int(dec.state.decodeUint())
|
||||
for i := 0; i < n && dec.err == nil; i++ {
|
||||
dec.printItem(indent, keyId)
|
||||
dec.printItem(indent+1, elemId)
|
||||
}
|
||||
}
|
||||
|
||||
func (dec *Decoder) printSlice(indent int, wire *wireType) {
|
||||
elemId := wire.SliceT.Elem
|
||||
n := int(dec.state.decodeUint())
|
||||
for i := 0; i < n && dec.err == nil; i++ {
|
||||
dec.printItem(indent, elemId)
|
||||
}
|
||||
}
|
||||
|
||||
func (dec *Decoder) printBuiltin(indent int, id typeId) {
|
||||
tab(indent)
|
||||
// printBuiltin prints a value not of a fundamental type, that is,
|
||||
// one whose type is known to gobs at bootstrap time.
|
||||
// That includes interfaces, although they may require
|
||||
// more unpacking down the line.
|
||||
func (deb *debugger) printBuiltin(indent tab, id typeId, n int) int {
|
||||
switch id {
|
||||
case tBool:
|
||||
if dec.state.decodeInt() == 0 {
|
||||
fmt.Printf("false\n")
|
||||
x, w := deb.readInt()
|
||||
if x == 0 {
|
||||
fmt.Fprintf(os.Stderr, "%sfalse\n", indent)
|
||||
} else {
|
||||
fmt.Printf("true\n")
|
||||
fmt.Fprintf(os.Stderr, "%strue\n", indent)
|
||||
}
|
||||
return w
|
||||
case tInt:
|
||||
fmt.Printf("%d\n", dec.state.decodeInt())
|
||||
x, w := deb.readInt()
|
||||
fmt.Fprintf(os.Stderr, "%s%d\n", indent, x)
|
||||
return w
|
||||
case tUint:
|
||||
fmt.Printf("%d\n", dec.state.decodeUint())
|
||||
x, w := deb.readInt()
|
||||
fmt.Fprintf(os.Stderr, "%s%d\n", indent, x)
|
||||
return w
|
||||
case tFloat:
|
||||
fmt.Printf("%g\n", floatFromBits(dec.state.decodeUint()))
|
||||
x, w := deb.readUint()
|
||||
fmt.Fprintf(os.Stderr, "%s%g\n", indent, floatFromBits(x))
|
||||
return w
|
||||
case tBytes:
|
||||
b := make([]byte, dec.state.decodeUint())
|
||||
dec.state.b.Read(b)
|
||||
fmt.Printf("% x\n", b)
|
||||
x, w := deb.readUint()
|
||||
b := make([]byte, x)
|
||||
deb.r.Read(b)
|
||||
fmt.Fprintf(os.Stderr, "%s{% x}=%q\n", indent, b, b)
|
||||
return w + int(x)
|
||||
case tString:
|
||||
b := make([]byte, dec.state.decodeUint())
|
||||
dec.state.b.Read(b)
|
||||
fmt.Printf("%q\n", b)
|
||||
x, w := deb.readUint()
|
||||
b := make([]byte, x)
|
||||
deb.r.Read(b)
|
||||
fmt.Fprintf(os.Stderr, "%s%q\n", indent, b)
|
||||
return w + int(x)
|
||||
case tInterface:
|
||||
b := make([]byte, dec.state.decodeUint())
|
||||
dec.state.b.Read(b)
|
||||
if len(b) == 0 {
|
||||
fmt.Printf("nil interface")
|
||||
} else {
|
||||
fmt.Printf("interface value; type %q\n", b)
|
||||
dec.debugFromBuffer(indent, true)
|
||||
}
|
||||
return deb.interfaceValue(indent, n)
|
||||
default:
|
||||
fmt.Print("unknown\n")
|
||||
}
|
||||
panic("unknown builtin")
|
||||
}
|
||||
|
||||
func (dec *Decoder) debugStruct(indent int, id typeId, wire *wireType) {
|
||||
tab(indent)
|
||||
fmt.Printf("%s struct {\n", id.name())
|
||||
|
||||
// ArrayValue:
|
||||
// uint(n) Value*n
|
||||
func (deb *debugger) arrayValue(indent tab, wire *wireType, n int) int {
|
||||
elemId := wire.ArrayT.Elem
|
||||
u, w := deb.readUint()
|
||||
length := int(u)
|
||||
for i := 0; i < length; i++ {
|
||||
w += deb.fieldValue(indent, elemId, n-w)
|
||||
}
|
||||
if length != wire.ArrayT.Len {
|
||||
fmt.Fprintf(os.Stderr, "%s(wrong length for array: %d should be %d)\n", indent, length, wire.ArrayT.Len)
|
||||
}
|
||||
return w
|
||||
}
|
||||
|
||||
// MapValue:
|
||||
// uint(n) (Value Value)*n [n (key, value) pairs]
|
||||
func (deb *debugger) mapValue(indent tab, wire *wireType, n int) int {
|
||||
keyId := wire.MapT.Key
|
||||
elemId := wire.MapT.Elem
|
||||
u, w := deb.readUint()
|
||||
length := int(u)
|
||||
for i := 0; i < length; i++ {
|
||||
w += deb.fieldValue(indent+1, keyId, n-w)
|
||||
w += deb.fieldValue(indent+1, elemId, n-w)
|
||||
}
|
||||
return w
|
||||
}
|
||||
|
||||
// SliceValue:
|
||||
// uint(n) (n Values)
|
||||
func (deb *debugger) sliceValue(indent tab, wire *wireType, n int) int {
|
||||
elemId := wire.SliceT.Elem
|
||||
u, w := deb.readUint()
|
||||
length := int(u)
|
||||
for i := 0; i < length; i++ {
|
||||
w += deb.fieldValue(indent, elemId, n-w)
|
||||
}
|
||||
return w
|
||||
}
|
||||
|
||||
// StructValue:
|
||||
// (int(fieldDelta) FieldValue)*
|
||||
func (deb *debugger) structValue(indent tab, id typeId, n int) int {
|
||||
deb.dump(n, "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
|
||||
state := newDecodeState(dec, dec.state.b)
|
||||
state.fieldnum = -1
|
||||
for dec.err == nil {
|
||||
delta := int(state.decodeUint())
|
||||
if delta < 0 {
|
||||
errorf("gob decode: corrupted data: negative delta")
|
||||
}
|
||||
fieldNum := -1
|
||||
indent++
|
||||
w := 0
|
||||
for {
|
||||
delta, wid := deb.readUint()
|
||||
w += wid
|
||||
n -= wid
|
||||
if delta == 0 { // struct terminator is zero delta fieldnum
|
||||
break
|
||||
}
|
||||
fieldNum := state.fieldnum + delta
|
||||
fieldNum += int(delta)
|
||||
if fieldNum < 0 || fieldNum >= len(strct.Field) {
|
||||
errorf("field number out of range")
|
||||
deb.dump(n, "field number out of range: prevField=%d delta=%d", fieldNum-int(delta), delta)
|
||||
break
|
||||
}
|
||||
tab(indent)
|
||||
fmt.Printf("%s(%d):\n", wire.StructT.Field[fieldNum].Name, fieldNum)
|
||||
dec.printItem(indent+1, strct.Field[fieldNum].Id)
|
||||
state.fieldnum = fieldNum
|
||||
}
|
||||
tab(indent)
|
||||
fmt.Printf(" } // end %s struct\n", id.name())
|
||||
}
|
||||
|
||||
func tab(indent int) {
|
||||
for i, w := 0, 0; i < indent; i += w {
|
||||
w = 10
|
||||
if i+w > indent {
|
||||
w = indent - i
|
||||
}
|
||||
fmt.Print("\t\t\t\t\t\t\t\t\t\t"[:w])
|
||||
fmt.Fprintf(os.Stderr, "%sfield %d:\t%s\n", indent, fieldNum, wire.StructT.Field[fieldNum].Name)
|
||||
wid = deb.fieldValue(indent+1, strct.Field[fieldNum].Id, n)
|
||||
w += wid
|
||||
n -= wid
|
||||
}
|
||||
indent--
|
||||
fmt.Fprintf(os.Stderr, "%s} // end %s struct\n", indent, id.name())
|
||||
deb.dump(n, ">> End of struct value of type %d %q", id, id.name())
|
||||
return w
|
||||
}
|
||||
|
||||
@ -49,14 +49,15 @@ func overflow(name string) os.ErrorString {
|
||||
|
||||
// decodeUintReader reads an encoded unsigned integer from an io.Reader.
|
||||
// Used only by the Decoder to read the message length.
|
||||
func decodeUintReader(r io.Reader, buf []byte) (x uint64, err os.Error) {
|
||||
_, err = r.Read(buf[0:1])
|
||||
func decodeUintReader(r io.Reader, buf []byte) (x uint64, width int, err os.Error) {
|
||||
width = 1
|
||||
_, err = r.Read(buf[0:width])
|
||||
if err != nil {
|
||||
return
|
||||
}
|
||||
b := buf[0]
|
||||
if b <= 0x7f {
|
||||
return uint64(b), nil
|
||||
return uint64(b), width, nil
|
||||
}
|
||||
nb := -int(int8(b))
|
||||
if nb > uint64Size {
|
||||
@ -75,6 +76,7 @@ func decodeUintReader(r io.Reader, buf []byte) (x uint64, err os.Error) {
|
||||
for i := 0; i < n; i++ {
|
||||
x <<= 8
|
||||
x |= uint64(buf[i])
|
||||
width++
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
@ -58,7 +58,7 @@ func (dec *Decoder) recvType(id typeId) {
|
||||
dec.wireType[id] = wire
|
||||
|
||||
// Load the next parcel.
|
||||
dec.recv()
|
||||
dec.recvMessage()
|
||||
}
|
||||
|
||||
// Decode reads the next value from the connection and stores
|
||||
@ -76,23 +76,28 @@ func (dec *Decoder) Decode(e interface{}) os.Error {
|
||||
return dec.DecodeValue(value)
|
||||
}
|
||||
|
||||
// recv reads the next count-delimited item from the input. It is the converse
|
||||
// of Encoder.send.
|
||||
func (dec *Decoder) recv() {
|
||||
// recvMessage reads the next count-delimited item from the input. It is the converse
|
||||
// of Encoder.writeMessage.
|
||||
func (dec *Decoder) recvMessage() {
|
||||
// Read a count.
|
||||
var nbytes uint64
|
||||
nbytes, dec.err = decodeUintReader(dec.r, dec.countBuf[0:])
|
||||
nbytes, _, dec.err = decodeUintReader(dec.r, dec.countBuf[0:])
|
||||
if dec.err != nil {
|
||||
return
|
||||
}
|
||||
dec.readMessage(int(nbytes), dec.r)
|
||||
}
|
||||
|
||||
// readMessage reads the next nbytes bytes from the input.
|
||||
func (dec *Decoder) readMessage(nbytes int, r io.Reader) {
|
||||
// Allocate the buffer.
|
||||
if nbytes > uint64(len(dec.buf)) {
|
||||
if nbytes > len(dec.buf) {
|
||||
dec.buf = make([]byte, nbytes+1000)
|
||||
}
|
||||
dec.byteBuffer = bytes.NewBuffer(dec.buf[0:nbytes])
|
||||
|
||||
// Read the data
|
||||
_, dec.err = io.ReadFull(dec.r, dec.buf[0:nbytes])
|
||||
_, dec.err = io.ReadFull(r, dec.buf[0:nbytes])
|
||||
if dec.err != nil {
|
||||
if dec.err == os.EOF {
|
||||
dec.err = io.ErrUnexpectedEOF
|
||||
@ -103,7 +108,7 @@ func (dec *Decoder) recv() {
|
||||
|
||||
// decodeValueFromBuffer grabs the next value from the input. The Decoder's
|
||||
// buffer already contains data. If the next item in the buffer is a type
|
||||
// descriptor, it may be necessary to reload the buffer, but recvType does that.
|
||||
// descriptor, it will be necessary to reload the buffer; recvType does that.
|
||||
func (dec *Decoder) decodeValueFromBuffer(value reflect.Value, ignoreInterfaceValue, countPresent bool) {
|
||||
for dec.state.b.Len() > 0 {
|
||||
// Receive a type id.
|
||||
@ -150,7 +155,7 @@ func (dec *Decoder) DecodeValue(value reflect.Value) os.Error {
|
||||
defer dec.mutex.Unlock()
|
||||
|
||||
dec.err = nil
|
||||
dec.recv()
|
||||
dec.recvMessage()
|
||||
if dec.err != nil {
|
||||
return dec.err
|
||||
}
|
||||
|
||||
@ -219,6 +219,54 @@ be predefined or be defined before the value in the stream.
|
||||
*/
|
||||
package gob
|
||||
|
||||
/*
|
||||
Grammar:
|
||||
|
||||
Tokens starting with a lower case letter are terminals; int(n)
|
||||
and uint(n) represent the signed/unsigned encodings of the value n.
|
||||
|
||||
GobStream:
|
||||
DelimitedMessage*
|
||||
DelimitedMessage:
|
||||
uint(lengthOfMessage) Message
|
||||
Message:
|
||||
TypeSequence TypedValue
|
||||
TypeSequence
|
||||
(TypeDefinition DelimitedTypeDefinition*)?
|
||||
DelimitedTypeDefinition:
|
||||
uint(lengthOfTypeDefinition) TypeDefinition
|
||||
TypedValue:
|
||||
int(typeId) Value
|
||||
TypeDefinition:
|
||||
int(-typeId) encodingOfWireType
|
||||
Value:
|
||||
ConcreteValue | InterfaceValue
|
||||
ConcreteValue:
|
||||
SingletonValue | StructValue
|
||||
SingletonValue:
|
||||
int(0) FieldValue
|
||||
InterfaceValue:
|
||||
NilInterfaceValue | NonNilInterfaceValue
|
||||
NilInterfaceValue:
|
||||
uint(0)
|
||||
NonNilInterfaceValue:
|
||||
ConcreteTypeName TypeSequence InterfaceContents
|
||||
ConcreteTypeName:
|
||||
uint(lengthOfName) [already read=n] name
|
||||
InterfaceContents:
|
||||
int(concreteTypeId) DelimitedValue
|
||||
DelimitedValue:
|
||||
uint(length) Value
|
||||
ArrayValue:
|
||||
uint(n) Value*n [n elements]
|
||||
MapValue:
|
||||
uint(n) (Value Value)*n [n (key, value) pairs]
|
||||
SliceValue:
|
||||
uint(n) Value*n [n elements]
|
||||
StructValue:
|
||||
(uint(fieldDelta) FieldValue)*
|
||||
*/
|
||||
|
||||
/*
|
||||
For implementers and the curious, here is an encoded example. Given
|
||||
type Point struct {x, y int}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user