2 files changed, 144 insertions, 0 deletions
diff --git a/internal/fmtio/fmtio.go b/internal/fmtio/fmtio.go
new file mode 100644
index 0000000..0e252d4
--- /dev/null
+++ b/internal/fmtio/fmtio.go
@@ -0,0 +1,79 @@
+// package fmtio provides basic utilities to format input and output
+package fmtio
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ed25519"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"git.sigsum.org/sigsum-go/pkg/hex"
+	"git.sigsum.org/sigsum-go/pkg/types"
+)
+
+func BytesFromStdin() ([]byte, error) {
+	b, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		return nil, err
+	}
+	return b, nil
+}
+
+// StringFromStdin reads bytes from stdin, parsing them as a string without
+// leading and trailing white space
+func StringFromStdin() (string, error) {
+	b, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		return "", err
+	}
+	return string(bytes.TrimSpace(b)), nil
+}
+
+func SignerFromHex(s string) (crypto.Signer, error) {
+	b, err := hex.Deserialize(s)
+	if err != nil {
+		return nil, err
+	}
+	if n := len(b); n != ed25519.PrivateKeySize {
+		return nil, fmt.Errorf("invalid size %d", n)
+	}
+	return ed25519.PrivateKey(b), nil
+}
+
+func PublicKeyFromHex(s string) (pub types.PublicKey, err error) {
+	b, err := hex.Deserialize(s)
+	if err != nil {
+		return pub, err
+	}
+	if n := len(b); n != types.PublicKeySize {
+		return pub, fmt.Errorf("invalid size %d", n)
+	}
+	copy(pub[:], b)
+	return
+}
+
+func KeyHashFromHex(s string) (h types.Hash, err error) {
+	b, err := hex.Deserialize(s)
+	if err != nil {
+		return h, err
+	}
+	if n := len(b); n != types.HashSize {
+		return h, fmt.Errorf("invalid size %d", n)
+	}
+	copy(h[:], b)
+	return
+}
+
+func SignatureFromHex(s string) (sig types.Signature, err error) {
+	b, err := hex.Deserialize(s)
+	if err != nil {
+		return sig, err
+	}
+	if n := len(b); n != types.SignatureSize {
+		return sig, fmt.Errorf("invalid size %d", n)
+	}
+	copy(sig[:], b)
+	return
+}
diff --git a/internal/options/options.go b/internal/options/options.go
new file mode 100644
index 0000000..cc8e02a
--- /dev/null
+++ b/internal/options/options.go
@@ -0,0 +1,65 @@
+package options
+
+import (
+	"flag"
+	"fmt"
+)
+
+const (
+	DefaultString = "default string"
+	DefaultUint64 = 18446744073709551615
+)
+
+// New initializes a flag set using the provided arguments.
+//
+//   - args should start with the (sub)command's name
+//   - usage is a function that prints a usage message
+//   - set is a function that sets the command's flag arguments
+//
+func New(args []string, usage func(), set func(*flag.FlagSet)) *flag.FlagSet {
+	if len(args) == 0 {
+		args = append(args, "")
+	}
+
+	fs := flag.NewFlagSet(args[0], flag.ExitOnError)
+	fs.Usage = func() {
+		usage()
+	}
+	set(fs)
+	fs.Parse(args[1:])
+	return fs
+}
+
+// AddString adds a string option to a flag set
+func AddString(fs *flag.FlagSet, opt *string, short, long, value string) {
+	fs.StringVar(opt, short, value, "")
+	fs.StringVar(opt, long, value, "")
+}
+
+// AdUint64 adds an uint64 option to a flag set
+func AddUint64(fs *flag.FlagSet, opt *uint64, short, long string, value uint64) {
+	fs.Uint64Var(opt, short, value, "")
+	fs.Uint64Var(opt, long, value, "")
+}
+
+// CheckString checks that a string option has a non-default value
+func CheckString(optionName, value string, err error) error {
+	if err != nil {
+		return err
+	}
+	if value == DefaultString {
+		return fmt.Errorf("%s is a required option", optionName)
+	}
+	return nil
+}
+
+// CheckUint checks that an uint64 option has a non-default value
+func CheckUint64(optionName string, value uint64, err error) error {
+	if err != nil {
+		return err
+	}
+	if value == DefaultUint64 {
+		return fmt.Errorf("%s is a required option", optionName)
+	}
+	return nil
+}