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// Copyright 2023 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.
// Code generated by "gen.bash" from internal/trace; DO NOT EDIT.
//go:build go1.23
package raw
import (
"bufio"
"encoding/binary"
"fmt"
"io"
"golang.org/x/exp/trace/internal/tracev2"
"golang.org/x/exp/trace/internal/version"
)
// Reader parses trace bytes with only very basic validation
// into an event stream.
type Reader struct {
r *bufio.Reader
v version.Version
specs []tracev2.EventSpec
}
// NewReader creates a new reader for the trace wire format.
func NewReader(r io.Reader) (*Reader, error) {
br := bufio.NewReader(r)
v, err := version.ReadHeader(br)
if err != nil {
return nil, err
}
return &Reader{r: br, v: v, specs: v.Specs()}, nil
}
// Version returns the version of the trace that we're reading.
func (r *Reader) Version() version.Version {
return r.v
}
// ReadEvent reads and returns the next trace event in the byte stream.
func (r *Reader) ReadEvent() (Event, error) {
evb, err := r.r.ReadByte()
if err == io.EOF {
return Event{}, io.EOF
}
if err != nil {
return Event{}, err
}
if int(evb) >= len(r.specs) || evb == 0 {
return Event{}, fmt.Errorf("invalid event type: %d", evb)
}
ev := tracev2.EventType(evb)
spec := r.specs[ev]
args, err := r.readArgs(len(spec.Args))
if err != nil {
return Event{}, err
}
if spec.IsStack {
len := int(args[1])
for i := 0; i < len; i++ {
// Each stack frame has four args: pc, func ID, file ID, line number.
frame, err := r.readArgs(4)
if err != nil {
return Event{}, err
}
args = append(args, frame...)
}
}
var data []byte
if spec.HasData {
data, err = r.readData()
if err != nil {
return Event{}, err
}
}
return Event{
Version: r.v,
Ev: ev,
Args: args,
Data: data,
}, nil
}
func (r *Reader) readArgs(n int) ([]uint64, error) {
var args []uint64
for i := 0; i < n; i++ {
val, err := binary.ReadUvarint(r.r)
if err != nil {
return nil, err
}
args = append(args, val)
}
return args, nil
}
func (r *Reader) readData() ([]byte, error) {
len, err := binary.ReadUvarint(r.r)
if err != nil {
return nil, err
}
var data []byte
for i := 0; i < int(len); i++ {
b, err := r.r.ReadByte()
if err != nil {
return nil, err
}
data = append(data, b)
}
return data, nil
}
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