Merge pull request #79 from willnorris/spdx

Add support for SPDX style headers

main.go

@@ -49,6 +49,7 @@ Flags:
 
 var (
 	skipExtensionFlags skipExtensionFlag
+	spdx               spdxFlag
 
 	holder    = flag.String("c", "Google LLC", "copyright holder")
 	license   = flag.String("l", "apache", "license type: apache, bsd, mit, mpl")
@@ -58,6 +59,15 @@ var (
 	checkonly = flag.Bool("check", false, "check only mode: verify presence of license headers and exit with non-zero code if missing")
 )
 
+func init() {
+	flag.Usage = func() {
+		fmt.Fprintln(os.Stderr, helpText)
+		flag.PrintDefaults()
+	}
+	flag.Var(&skipExtensionFlags, "skip", "To skip files to check/add the header file, for example: -skip rb -skip go")
+	flag.Var(&spdx, "s", "Include SPDX identifier in license header. Set -s=only to only include SPDX identifier.")
+}
+
 type skipExtensionFlag []string
 
 func (i *skipExtensionFlag) String() string {
@@ -69,41 +79,54 @@ func (i *skipExtensionFlag) Set(value string) error {
 	return nil
 }
 
-func main() {
-	flag.Usage = func() {
-		fmt.Fprintln(os.Stderr, helpText)
-		flag.PrintDefaults()
+// spdxFlag defines the line flag behavior for specifying SPDX support.
+type spdxFlag string
+
+const (
+	spdxOff  spdxFlag = ""
+	spdxOn   spdxFlag = "true" // value set by flag package on bool flag
+	spdxOnly spdxFlag = "only"
+)
+
+// IsBoolFlag causes a bare '-s' flag to be set as the string 'true'.  This
+// allows the use of the bare '-s' or setting a string '-s=only'.
+func (i *spdxFlag) IsBoolFlag() bool { return true }
+func (i *spdxFlag) String() string   { return string(*i) }
+
+func (i *spdxFlag) Set(value string) error {
+	v := spdxFlag(value)
+	if v != spdxOn && v != spdxOnly {
+		return fmt.Errorf("error: flag 's' expects '%v' or '%v'", spdxOn, spdxOnly)
 	}
-	flag.Var(&skipExtensionFlags, "skip", "To skip files to check/add the header file, for example: -skip rb -skip go")
+	*i = v
+	return nil
+}
+
+func main() {
 	flag.Parse()
 	if flag.NArg() == 0 {
 		flag.Usage()
 		os.Exit(1)
 	}
 
-	data := &copyrightData{
-		Year:   *year,
-		Holder: *holder,
+	// map legacy license values
+	if t, ok := legacyLicenseTypes[*license]; ok {
+		*license = t
 	}
 
-	var t *template.Template
-	if *licensef != "" {
-		d, err := ioutil.ReadFile(*licensef)
-		if err != nil {
-			log.Printf("license file: %v", err)
-			os.Exit(1)
-		}
-		t, err = template.New("").Parse(string(d))
-		if err != nil {
-			log.Printf("license file: %v", err)
-			os.Exit(1)
-		}
-	} else {
-		t = licenseTemplate[*license]
-		if t == nil {
-			log.Printf("unknown license: %s", *license)
-			os.Exit(1)
-		}
+	data := licenseData{
+		Year:   *year,
+		Holder: *holder,
+		SPDXID: *license,
+	}
+
+	tpl, err := fetchTemplate(*license, *licensef, spdx)
+	if err != nil {
+		log.Fatal(err)
+	}
+	t, err := template.New("").Parse(tpl)
+	if err != nil {
+		log.Fatal(err)
 	}
 
 	// process at most 1000 files in parallel
@@ -189,7 +212,7 @@ func walk(ch chan<- *file, start string) {
 // addLicense add a license to the file if missing.
 //
 // It returns true if the file was updated.
-func addLicense(path string, fmode os.FileMode, tmpl *template.Template, data *copyrightData) (bool, error) {
+func addLicense(path string, fmode os.FileMode, tmpl *template.Template, data licenseData) (bool, error) {
 	var lic []byte
 	var err error
 	lic, err = licenseHeader(path, tmpl, data)
@@ -227,32 +250,32 @@ func fileHasLicense(path string) (bool, error) {
 	return hasLicense(b) || isGenerated(b), nil
 }
 
-func licenseHeader(path string, tmpl *template.Template, data *copyrightData) ([]byte, error) {
+func licenseHeader(path string, tmpl *template.Template, data licenseData) ([]byte, error) {
 	var lic []byte
 	var err error
 	switch fileExtension(path) {
 	default:
 		return nil, nil
 	case ".c", ".h", ".gv":
-		lic, err = prefix(tmpl, data, "/*", " * ", " */")
+		lic, err = executeTemplate(tmpl, data, "/*", " * ", " */")
 	case ".js", ".mjs", ".cjs", ".jsx", ".tsx", ".css", ".scss", ".sass", ".tf", ".ts":
-		lic, err = prefix(tmpl, data, "/**", " * ", " */")
+		lic, err = executeTemplate(tmpl, data, "/**", " * ", " */")
 	case ".cc", ".cpp", ".cs", ".go", ".hh", ".hpp", ".java", ".m", ".mm", ".proto", ".rs", ".scala", ".swift", ".dart", ".groovy", ".kt", ".kts", ".v", ".sv":
-		lic, err = prefix(tmpl, data, "", "// ", "")
+		lic, err = executeTemplate(tmpl, data, "", "// ", "")
 	case ".py", ".sh", ".yaml", ".yml", ".dockerfile", "dockerfile", ".rb", "gemfile", ".tcl", ".bzl":
-		lic, err = prefix(tmpl, data, "", "# ", "")
+		lic, err = executeTemplate(tmpl, data, "", "# ", "")
 	case ".el", ".lisp":
-		lic, err = prefix(tmpl, data, "", ";; ", "")
+		lic, err = executeTemplate(tmpl, data, "", ";; ", "")
 	case ".erl":
-		lic, err = prefix(tmpl, data, "", "% ", "")
+		lic, err = executeTemplate(tmpl, data, "", "% ", "")
 	case ".hs", ".sql", ".sdl":
-		lic, err = prefix(tmpl, data, "", "-- ", "")
+		lic, err = executeTemplate(tmpl, data, "", "-- ", "")
 	case ".html", ".xml", ".vue":
-		lic, err = prefix(tmpl, data, "<!--", " ", "-->")
+		lic, err = executeTemplate(tmpl, data, "<!--", " ", "-->")
 	case ".php":
-		lic, err = prefix(tmpl, data, "", "// ", "")
+		lic, err = executeTemplate(tmpl, data, "", "// ", "")
 	case ".ml", ".mli", ".mll", ".mly":
-		lic, err = prefix(tmpl, data, "(**", "   ", "*)")
+		lic, err = executeTemplate(tmpl, data, "(**", "   ", "*)")
 	}
 	return lic, err
 }
@@ -308,5 +331,6 @@ func hasLicense(b []byte) bool {
 		n = len(b)
 	}
 	return bytes.Contains(bytes.ToLower(b[:n]), []byte("copyright")) ||
-		bytes.Contains(bytes.ToLower(b[:n]), []byte("mozilla public"))
+		bytes.Contains(bytes.ToLower(b[:n]), []byte("mozilla public")) ||
+		bytes.Contains(bytes.ToLower(b[:n]), []byte("SPDX-License-Identifier"))
 }

testdata/custom.tpl

@@ -0,0 +1,3 @@
+Copyright {{.Year}} {{.Holder}}
+
+Custom License Template

tmpl.go

@@ -19,27 +19,69 @@ import (
 	"bytes"
 	"fmt"
 	"html/template"
+	"io/ioutil"
 	"strings"
 	"unicode"
 )
 
-var licenseTemplate = make(map[string]*template.Template)
-
-func init() {
-	licenseTemplate["apache"] = template.Must(template.New("").Parse(tmplApache))
-	licenseTemplate["mit"] = template.Must(template.New("").Parse(tmplMIT))
-	licenseTemplate["bsd"] = template.Must(template.New("").Parse(tmplBSD))
-	licenseTemplate["mpl"] = template.Must(template.New("").Parse(tmplMPL))
+var licenseTemplate = map[string]string{
+	"Apache-2.0": tmplApache,
+	"MIT":        tmplMIT,
+	"bsd":        tmplBSD,
+	"MPL-2.0":    tmplMPL,
 }
 
-type copyrightData struct {
-	Year   string
-	Holder string
+// maintain backwards compatibility by mapping legacy license types to their
+// SPDX equivalents.
+var legacyLicenseTypes = map[string]string{
+	"apache": "Apache-2.0",
+	"mit":    "MIT",
+	"mpl":    "MPL-2.0",
 }
 
-// prefix will execute a license template t with data d
+// licenseData specifies the data used to fill out a license template.
+type licenseData struct {
+	Year   string // Copyright year(s).
+	Holder string // Name of the copyright holder.
+	SPDXID string // SPDX Identifier
+}
+
+// fetchTemplate returns the license template for the specified license and
+// optional templateFile. If templateFile is provided, the license is read
+// from the specified file. Otherwise, a template is loaded for the specified
+// license, if recognized.
+func fetchTemplate(license string, templateFile string, spdx spdxFlag) (string, error) {
+	var t string
+	if spdx == spdxOnly {
+		t = tmplSPDX
+	} else if templateFile != "" {
+		d, err := ioutil.ReadFile(templateFile)
+		if err != nil {
+			return "", fmt.Errorf("license file: %w", err)
+		}
+
+		t = string(d)
+	} else {
+		t = licenseTemplate[license]
+		if t == "" {
+			if spdx == spdxOn {
+				// unknown license, but SPDX headers requested
+				t = tmplSPDX
+			} else {
+				return "", fmt.Errorf("unknown license: %q. Include the '-s' flag to request SPDX style headers using this license.", license)
+			}
+		} else if spdx == spdxOn {
+			// append spdx headers to recognized license
+			t = t + spdxSuffix
+		}
+	}
+
+	return t, nil
+}
+
+// executeTemplate will execute a license template t with data d
 // and prefix the result with top, middle and bottom.
-func prefix(t *template.Template, d *copyrightData, top, mid, bot string) ([]byte, error) {
+func executeTemplate(t *template.Template, d licenseData, top, mid, bot string) ([]byte, error) {
 	var buf bytes.Buffer
 	if err := t.Execute(&buf, d); err != nil {
 		return nil, err
@@ -99,3 +141,8 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.`
 const tmplMPL = `This Source Code Form is subject to the terms of the Mozilla Public
 License, v. 2.0. If a copy of the MPL was not distributed with this
 file, You can obtain one at https://mozilla.org/MPL/2.0/.`
+
+const tmplSPDX = `{{ if and .Year .Holder }}Copyright {{.Year}} {{.Holder}}
+{{ end }}SPDX-License-Identifier: {{.SPDXID}}`
+
+const spdxSuffix = "\n\nSPDX-License-Identifier: {{.SPDXID}}"

tmpl_test.go

@@ -0,0 +1,140 @@
+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"errors"
+	"html/template"
+	"os"
+	"testing"
+)
+
+func init() {
+	// ensure that pre-defined templates must parse
+	template.Must(template.New("").Parse(tmplApache))
+	template.Must(template.New("").Parse(tmplMIT))
+	template.Must(template.New("").Parse(tmplBSD))
+	template.Must(template.New("").Parse(tmplMPL))
+}
+
+func TestFetchTemplate(t *testing.T) {
+	tests := []struct {
+		description  string   // test case description
+		license      string   // license passed to fetchTemplate
+		templateFile string   // templatefile passed to fetchTemplate
+		spdx         spdxFlag // spdx value passed to fetchTemplate
+		wantTemplate string   // expected returned template
+		wantErr      error    // expected returned error
+	}{
+		// custom template files
+		{
+			"non-existant template file",
+			"",
+			"/does/not/exist",
+			spdxOff,
+			"",
+			os.ErrNotExist,
+		},
+		{
+			"custom template file",
+			"",
+			"testdata/custom.tpl",
+			spdxOff,
+			"Copyright {{.Year}} {{.Holder}}\n\nCustom License Template\n",
+			nil,
+		},
+
+		{
+			"unknown license",
+			"unknown",
+			"",
+			spdxOff,
+			"",
+			errors.New(`unknown license: "unknown". Include the '-s' flag to request SPDX style headers using this license.`),
+		},
+
+		// pre-defined license templates, no SPDX
+		{
+			"apache license template",
+			"Apache-2.0",
+			"",
+			spdxOff,
+			tmplApache,
+			nil,
+		},
+		{
+			"mit license template",
+			"MIT",
+			"",
+			spdxOff,
+			tmplMIT,
+			nil,
+		},
+		{
+			"bsd license template",
+			"bsd",
+			"",
+			spdxOff,
+			tmplBSD,
+			nil,
+		},
+		{
+			"mpl license template",
+			"MPL-2.0",
+			"",
+			spdxOff,
+			tmplMPL,
+			nil,
+		},
+
+		// SPDX variants
+		{
+			"apache license template with SPDX added",
+			"Apache-2.0",
+			"",
+			spdxOn,
+			tmplApache + spdxSuffix,
+			nil,
+		},
+		{
+			"apache license template with SPDX only",
+			"Apache-2.0",
+			"",
+			spdxOnly,
+			tmplSPDX,
+			nil,
+		},
+		{
+			"unknown license with SPDX only",
+			"unknown",
+			"",
+			spdxOnly,
+			tmplSPDX,
+			nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			tpl, err := fetchTemplate(tt.license, tt.templateFile, tt.spdx)
+			if tt.wantErr != nil && (err == nil || (!errors.Is(err, tt.wantErr) && err.Error() != tt.wantErr.Error())) {
+				t.Fatalf("fetchTemplate(%q, %q) returned error: %#v, want %#v", tt.license, tt.templateFile, err, tt.wantErr)
+			}
+			if tpl != tt.wantTemplate {
+				t.Errorf("fetchTemplate(%q, %q) returned template: %q, want %q", tt.license, tt.templateFile, tpl, tt.wantTemplate)
+			}
+		})
+	}
+}