add subcommand that prints licenses, and link to licenses from the webadmin/webaccount/webmail interfaces

mox-/licenses.go

@@ -0,0 +1,55 @@
+package mox
+
+import (
+	"fmt"
+	"io"
+	"io/fs"
+	"strings"
+)
+
+var LicensesFsys fs.FS
+
+// LicensesWrite writes the licenses to dst.
+func LicensesWrite(dst io.Writer) error {
+	copyFile := func(p string) error {
+		f, err := LicensesFsys.Open(p)
+		if err != nil {
+			return fmt.Errorf("open license file: %v", err)
+		}
+		if _, err := io.Copy(dst, f); err != nil {
+			return fmt.Errorf("copy license file: %v", err)
+		}
+		if err := f.Close(); err != nil {
+			return fmt.Errorf("close license file: %v", err)
+		}
+		return nil
+	}
+
+	if _, err := fmt.Fprintf(dst, "# github.com/mjl-/mox/LICENSE\n\n"); err != nil {
+		return err
+	}
+	if err := copyFile("LICENSE.MIT"); err != nil {
+		return err
+	}
+
+	if _, err := fmt.Fprintf(dst, "\n\n# https://publicsuffix.org - Public Suffix List Mozilla\n\n"); err != nil {
+		return err
+	}
+	if err := copyFile("LICENSE.MPLv2.0"); err != nil {
+		return err
+	}
+
+	err := fs.WalkDir(LicensesFsys, "licenses", func(path string, d fs.DirEntry, err error) error {
+		if !d.Type().IsRegular() {
+			return nil
+		}
+		if _, err := fmt.Fprintf(dst, "\n\n# %s\n\n", strings.TrimPrefix(path, "licenses/")); err != nil {
+			return err
+		}
+		return copyFile(path)
+	})
+	if err != nil {
+		return fmt.Errorf("walk licenses: %v", err)
+	}
+	return nil
+}