1 files changed, 84 insertions, 0 deletions
diff --git a/internal/ctflag/ctflag.go b/internal/ctflag/ctflag.go
new file mode 100644
index 0000000..c6a7559
--- /dev/null
+++ b/internal/ctflag/ctflag.go
@@ -0,0 +1,84 @@
+// BSD 2-Clause License
+//
+// Copyright (c) 2022, the ct authors
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+//  1. Redistributions of source code must retain the above copyright notice, this
+//     list of conditions and the following disclaimer.
+//
+//  2. Redistributions in binary form must reproduce the above copyright notice,
+//     this list of conditions and the following disclaimer in the documentation
+//     and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// From:
+// https://gitlab.torproject.org/rgdd/ct/-/tree/main/internal/ctflag
+package ctflag
+
+import (
+	"flag"
+	"fmt"
+)
+
+// NewFlagSet outputs a new flag set that continues on errors without standard
+// library prints (so that the application gets full control of error handling)
+func NewFlagSet() flag.FlagSet {
+	fs := flag.NewFlagSet("", flag.ContinueOnError)
+	fs.SetOutput(discard{})
+	return *fs
+}
+
+// Parse tries to parse command-line options into a flag set.  Trailing
+// arguments are not permitted, i.e., all options must be parseable flags.
+func Parse(fs flag.FlagSet, args []string) error {
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+	if len(fs.Args()) != 0 {
+		return fmt.Errorf("trailing arguments: %v", fs.Args())
+	}
+	return nil
+}
+
+// WantHelp outputs true if the index i is out-of-range, or if the argument at
+// index i starts with "help" or "-"
+func WantHelp(args []string, i int) bool {
+	if i+1 > len(args) {
+		return true
+	}
+	if args[i] == "help" {
+		return true
+	}
+	return len(args[i]) == 0 || args[i][0] == '-'
+}
+
+// String adds a new string option to a flag set
+func String(fs *flag.FlagSet, opt *string, short, long, value string) {
+	fs.StringVar(opt, short, value, "")
+	fs.StringVar(opt, long, value, "")
+}
+
+// Bool adds a new bool option to a flag set
+func Bool(fs *flag.FlagSet, opt *bool, short, long string, value bool) {
+	fs.BoolVar(opt, short, value, "")
+	fs.BoolVar(opt, long, value, "")
+}
+
+type discard struct{}
+
+func (d discard) Write(_ []byte) (int, error) {
+	return 0, nil
+}