Restructure constant generation

templates/const.go.tpl → gen/const.go.tpl

@@ -6,7 +6,6 @@ type Codec uint64
 
 // These are multicodec-packed content types.
 const (
-{{ range .Codecs }}// {{ if .IsDeprecated }}Deprecated: {{ end }}{{ .Tag }}{{ if .Description }}: {{ .Description }}{{ end }}
-   {{ .VarName }} Codec = {{ .Code }}
-{{ end }}
-)
+{{ range . }}// {{ if .IsDeprecated }}Deprecated: {{ end }}{{ .Tag }}{{ if .Description }}: {{ .Description }}{{ end }}
+{{ .VarName }} Codec = {{ .Code }} // {{ .Name }}
+{{ end }})

gen/gen.go

@@ -9,9 +9,59 @@ import (
 	"text/template"
 )
 
-// TemplateData is the data structure that is passed into the go template
-type TemplateData struct {
-	Codecs []Codec
+// Codec represents a row in the canonical multicodec table
+type Codec struct {
+	Name        string
+	Tag         string
+	Code        string
+	Description string
+}
+
+// IsDeprecated returns true if the description contains the word deprecated
+func (c Codec) IsDeprecated() bool {
+	return strings.Contains(strings.ToLower(c.Description), "deprecated")
+}
+
+// VarName returns the variable name to be used in Go for this codec
+// Implementation adapted from https://github.com/iancoleman/strcase
+func (c Codec) VarName() string {
+	if c.Name == "" {
+		return c.Name
+	}
+
+	// convert the string to camelcase
+	n := strings.Builder{}
+	n.Grow(len(c.Name))
+	capNext := true
+	for i, v := range []byte(c.Name) {
+		vIsCap := v >= 'A' && v <= 'Z'
+		vIsLow := v >= 'a' && v <= 'z'
+		vIsNum := v >= '0' && v <= '9'
+		if capNext {
+			if vIsLow {
+				v += 'A'
+				v -= 'a'
+			}
+		} else if i == 0 {
+			if vIsCap {
+				v += 'a'
+				v -= 'A'
+			}
+		}
+		if vIsCap || vIsLow {
+			n.WriteByte(v)
+			capNext = false
+		} else if vIsNum {
+			n.WriteByte(v)
+			capNext = true
+		} else {
+			capNext = v == '_' || v == ' ' || v == '-' || v == '.'
+			if capNext {
+				n.WriteByte('_')
+			}
+		}
+	}
+	return n.String()
 }
 
 func main() {
@@ -28,48 +78,32 @@ func main() {
 	}
 
 	codecs := make([]Codec, len(records)-1)
-	for i, record := range records {
-
-		// Skip header line
-		if i == 0 {
-			continue
-		}
-
-		c := Codec{
+	for i, record := range records[1:] { // Skip header line
+		codecs[i] = Codec{
 			Name:        strings.TrimSpace(record[0]),
 			Tag:         strings.TrimSpace(record[1]),
 			Code:        strings.TrimSpace(record[2]),
 			Description: strings.TrimSpace(record[3]),
 		}
-		codecs[i-1] = c
 	}
 
-	tData := TemplateData{
-		Codecs: codecs,
+	tplFileName := "const.go.tpl"
+	t, err := template.
+		New(tplFileName).
+		Funcs(template.FuncMap{"ToTitle": strings.Title}).
+		ParseFiles(path.Join("gen", tplFileName))
+	if err != nil {
+		log.Fatal(err)
 	}
 
-	templates := []string{"codecs", "const"}
-	for _, templateName := range templates {
-
-		tplFileName := templateName + ".go.tpl"
-		t, err := template.
-			New(tplFileName).
-			Funcs(template.FuncMap{"ToTitle": strings.Title}).
-			ParseFiles(path.Join("templates", tplFileName))
-		if err != nil {
-			log.Fatal(err)
-		}
-
-		out, err := os.Create(templateName + ".go")
-		if err != nil {
-			log.Fatal(err)
-		}
+	out, err := os.Create("const.go")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer out.Close()
 
-		err = t.Execute(out, tData)
-		if err != nil {
-			out.Close()
-			log.Fatal(err)
-		}
-		out.Close()
+	err = t.Execute(out, codecs)
+	if err != nil {
+		log.Fatal(err)
 	}
 }

init.go

@@ -2,3 +2,4 @@ package multicodec
 
 //go:generate go run ./gen/
 //go:generate go fmt ./...
+//go:generate stringer -type=Codec -linecomment