windows_exporter/perflib/nametable.go

82 lines
1.6 KiB
Go

package perflib
import (
"bytes"
"fmt"
"strconv"
"sync"
)
// Initialize global name tables
// TODO: profiling, add option to disable name tables if necessary
// Not sure if we should resolve the names at all or just have the caller do it on demand
// (for many use cases the index is sufficient)
var CounterNameTable = *QueryNameTable("Counter 009")
func (p *perfObjectType) LookupName() string {
return CounterNameTable.LookupString(p.ObjectNameTitleIndex)
}
type NameTable struct {
once sync.Once
name string
table struct {
index map[uint32]string
string map[string]uint32
}
}
func (t *NameTable) LookupString(index uint32) string {
t.initialize()
return t.table.index[index]
}
func (t *NameTable) LookupIndex(str string) uint32 {
t.initialize()
return t.table.string[str]
}
// QueryNameTable Query a perflib name table from the registry. Specify the type and the language
// code (i.e. "Counter 009" or "Help 009") for English language.
func QueryNameTable(tableName string) *NameTable {
return &NameTable{
name: tableName,
}
}
func (t *NameTable) initialize() {
t.once.Do(func() {
t.table.index = make(map[uint32]string)
t.table.string = make(map[string]uint32)
buffer, err := queryRawData(t.name)
if err != nil {
panic(err)
}
r := bytes.NewReader(buffer)
for {
index, err := readUTF16String(r)
if err != nil {
break
}
desc, err := readUTF16String(r)
if err != nil {
break
}
if err != nil {
panic(fmt.Sprint("Invalid index ", index))
}
indexInt, _ := strconv.Atoi(index)
t.table.index[uint32(indexInt)] = desc
t.table.string[desc] = uint32(indexInt)
}
})
}