cpe: switch to new binding implementation

Signed-off-by: Hank Donnay <hdonnay@redhat.com>
Change-Id: Icc05f1b5ebaae2f6ac6bc218dfd8a76b6a6a6964

Author: hdonnay

toolkit/types/cpe/bind.go

@@ -8,6 +8,8 @@ import (
 )
 
 // BindFS returns the WFN bound as CPE 2.3 formatted string.
+//
+// Deprecated: use [WFN.AppendText].
 func (w WFN) BindFS() string {
 	b := strings.Builder{}
 	b.WriteString(`cpe:2.3`)

toolkit/types/cpe/marshaling.go

@@ -9,14 +9,13 @@ import (
 
 // MarshalText implements [encoding.TextMarshaler].
 func (w *WFN) MarshalText() ([]byte, error) {
-	switch err := w.Valid(); {
-	case err == nil:
-	case errors.Is(err, ErrUnset):
-		return []byte{}, nil
-	default:
-		return nil, err
-	}
-	return []byte(w.BindFS()), nil
+	// Guess at a good initial size. Calculated via finding the mean size across
+	// the CPE Name dictionary and then rounding it up.
+	//
+	// 	zcat testdata/dictionary.list.gz | awk '/^#/{next}/^$/{next}{ct++;sum+=length($0)}END{print sum/ct}'
+	// 	55.9444 = 64
+	b := make([]byte, 0, 64)
+	return w.AppendText(b)
 }
 
 // UnmarshalText implements [encoding.TextUnmarshaler].

toolkit/types/cpe/wfn.go

@@ -204,7 +204,11 @@ func (w WFN) String() string {
 	case errors.Is(err, ErrUnset):
 		return ""
 	}
-	return w.BindFS()
+	b, _ := w.AppendText(make([]byte, 0, 64))
+	if len(b) == 0 {
+		return ""
+	}
+	return string(b)
 }
 
 // GoString implements [fmt.GoStringer].

toolkit/types/cpe/wfn_test.go

@@ -2,6 +2,7 @@ package cpe
 
 import (
 	"bufio"
+	"bytes"
 	"compress/gzip"
 	"errors"
 	"fmt"
@@ -451,22 +452,31 @@ func TestDictionary(t *testing.T) {
 	defer gz.Close()
 
 	s := bufio.NewScanner(gz)
+	defer func() {
+		if err := s.Err(); err != nil {
+			t.Error(err)
+		}
+	}()
+	back := make([]byte, 0, 128)
 	for i := 1; s.Scan(); i++ {
 		in := s.Text()
 		if len(in) == 0 || strings.HasPrefix(in, "#") {
 			continue
 		}
-		wfn, err := Unbind(in)
+
+		var wfn WFN
+		if err := wfn.UnmarshalFS(in); err != nil {
+			t.Fatalf("%v: %#q", err, in)
+		}
+		b, err := wfn.AppendText(back[:0])
 		if err != nil {
 			t.Fatalf("%v: %#q", err, in)
 		}
-		if got, want := wfn.BindFS(), s.Text(); got != want {
-			t.Logf(fmt, i, in, got, want)
+
+		if got, want := b, s.Bytes(); !bytes.Equal(got, want) {
+			t.Logf(fmt, i, in, string(got), string(want))
 			t.Logf("wfn: %#v", wfn)
 			t.Fail()
 		}
 	}
-	if err := s.Err(); err != nil {
-		t.Error(err)
-	}
 }