ac8b4718bd
Imported golang.org/x/telemetry@9c0d19e to avoid go version requirement change. For #3815 For golang/go#70056
83 lines
1.8 KiB
Go
83 lines
1.8 KiB
Go
// 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.
|
|
|
|
package counter
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"strings"
|
|
"unsafe"
|
|
|
|
"golang.org/x/telemetry/internal/mmap"
|
|
)
|
|
|
|
type File struct {
|
|
Meta map[string]string
|
|
Count map[string]uint64
|
|
}
|
|
|
|
func Parse(filename string, data []byte) (*File, error) {
|
|
if !bytes.HasPrefix(data, []byte(hdrPrefix)) || len(data) < pageSize {
|
|
if len(data) < pageSize {
|
|
return nil, fmt.Errorf("%s: file too short (%d<%d)", filename, len(data), pageSize)
|
|
}
|
|
return nil, fmt.Errorf("%s: wrong hdr (not %q)", filename, hdrPrefix)
|
|
}
|
|
corrupt := func() (*File, error) {
|
|
// TODO(rfindley): return a useful error message.
|
|
return nil, fmt.Errorf("%s: corrupt counter file", filename)
|
|
}
|
|
|
|
f := &File{
|
|
Meta: make(map[string]string),
|
|
Count: make(map[string]uint64),
|
|
}
|
|
np := round(len(hdrPrefix), 4)
|
|
hdrLen := *(*uint32)(unsafe.Pointer(&data[np]))
|
|
if hdrLen > pageSize {
|
|
return corrupt()
|
|
}
|
|
meta := data[np+4 : hdrLen]
|
|
if i := bytes.IndexByte(meta, 0); i >= 0 {
|
|
meta = meta[:i]
|
|
}
|
|
m := &mappedFile{
|
|
meta: string(meta),
|
|
hdrLen: hdrLen,
|
|
mapping: &mmap.Data{Data: data},
|
|
}
|
|
|
|
lines := strings.Split(m.meta, "\n")
|
|
for _, line := range lines {
|
|
if line == "" {
|
|
continue
|
|
}
|
|
k, v, ok := strings.Cut(line, ": ")
|
|
if !ok {
|
|
return corrupt()
|
|
}
|
|
f.Meta[k] = v
|
|
}
|
|
|
|
for i := uint32(0); i < numHash; i++ {
|
|
headOff := hdrLen + hashOff + i*4
|
|
head := m.load32(headOff)
|
|
off := head
|
|
for off != 0 {
|
|
ename, next, v, ok := m.entryAt(off)
|
|
if !ok {
|
|
return corrupt()
|
|
}
|
|
if _, ok := f.Count[string(ename)]; ok {
|
|
return corrupt()
|
|
}
|
|
ctrName := DecodeStack(string(ename))
|
|
f.Count[ctrName] = v.Load()
|
|
off = next
|
|
}
|
|
}
|
|
return f, nil
|
|
}
|