From 1073b463b24b2b28541e270099b470265ad87798 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Fri, 28 Feb 2020 12:32:13 +0700
Subject: [PATCH] re-add remove PSK decoding function, and deprecate it

---
 codec.go      |  68 ++++++++++++++++++++++++++++
 codec_test.go | 122 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 190 insertions(+)
 create mode 100644 codec.go
 create mode 100644 codec_test.go

diff --git a/codec.go b/codec.go
new file mode 100644
index 0000000..bb20a61
--- /dev/null
+++ b/codec.go
@@ -0,0 +1,68 @@
+package pnet
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/base64"
+	"encoding/hex"
+	"fmt"
+	"io"
+)
+
+var (
+	pathPSKv1  = []byte("/key/swarm/psk/1.0.0/")
+	pathBin    = "/bin/"
+	pathBase16 = "/base16/"
+	pathBase64 = "/base64/"
+)
+
+func readHeader(r *bufio.Reader) ([]byte, error) {
+	header, err := r.ReadBytes('\n')
+	if err != nil {
+		return nil, err
+	}
+
+	return bytes.TrimRight(header, "\r\n"), nil
+}
+
+func expectHeader(r *bufio.Reader, expected []byte) error {
+	header, err := readHeader(r)
+	if err != nil {
+		return err
+	}
+	if !bytes.Equal(header, expected) {
+		return fmt.Errorf("expected file header %s, got: %s", pathPSKv1, header)
+	}
+	return nil
+}
+
+// DecodeV1PSK reads a Multicodec encoded V1 PSK.
+//
+// Deprecated: This functionality will soon be removed from libp2p.
+func DecodeV1PSK(in io.Reader) ([]byte, error) {
+	reader := bufio.NewReader(in)
+	if err := expectHeader(reader, pathPSKv1); err != nil {
+		return nil, err
+	}
+	header, err := readHeader(reader)
+	if err != nil {
+		return nil, err
+	}
+
+	var decoder io.Reader
+	switch string(header) {
+	case pathBase16:
+		decoder = hex.NewDecoder(reader)
+	case pathBase64:
+		decoder = base64.NewDecoder(base64.StdEncoding, reader)
+	case pathBin:
+		decoder = reader
+	default:
+		return nil, fmt.Errorf("unknown encoding: %s", header)
+	}
+	out := make([]byte, 32)
+	if _, err = io.ReadFull(decoder, out[:]); err != nil {
+		return nil, err
+	}
+	return out, nil
+}
diff --git a/codec_test.go b/codec_test.go
new file mode 100644
index 0000000..b4b9272
--- /dev/null
+++ b/codec_test.go
@@ -0,0 +1,122 @@
+package pnet
+
+import (
+	"bytes"
+	"encoding/base64"
+	"testing"
+)
+
+func bufWithBase(base string, windows bool) *bytes.Buffer {
+	b := &bytes.Buffer{}
+	b.Write(pathPSKv1)
+	if windows {
+		b.WriteString("\r")
+	}
+	b.WriteString("\n")
+	b.WriteString(base)
+	if windows {
+		b.WriteString("\r")
+	}
+	b.WriteString("\n")
+	return b
+}
+
+func TestDecodeHex(t *testing.T) {
+	testDecodeHex(t, true)
+	testDecodeHex(t, false)
+}
+
+func TestDecodeBad(t *testing.T) {
+	testDecodeBad(t, true)
+	testDecodeBad(t, false)
+}
+
+func testDecodeBad(t *testing.T, windows bool) {
+	b := bufWithBase("/verybadbase/", windows)
+	b.WriteString("Have fun decoding that key")
+
+	_, err := DecodeV1PSK(b)
+	if err == nil {
+		t.Fatal("expected 'unknown encoding' got nil")
+	}
+}
+
+func testDecodeHex(t *testing.T, windows bool) {
+	b := bufWithBase("/base16/", windows)
+	for i := 0; i < 32; i++ {
+		b.WriteString("FF")
+	}
+
+	psk, err := DecodeV1PSK(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for _, b := range psk {
+		if b != 255 {
+			t.Fatal("byte was wrong")
+		}
+	}
+}
+
+func TestDecodeB64(t *testing.T) {
+	testDecodeB64(t, true)
+	testDecodeB64(t, false)
+}
+
+func testDecodeB64(t *testing.T, windows bool) {
+	b := bufWithBase("/base64/", windows)
+	key := make([]byte, 32)
+	for i := 0; i < 32; i++ {
+		key[i] = byte(i)
+	}
+
+	e := base64.NewEncoder(base64.StdEncoding, b)
+	_, err := e.Write(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = e.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	psk, err := DecodeV1PSK(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i, b := range psk {
+		if b != psk[i] {
+			t.Fatal("byte was wrong")
+		}
+	}
+
+}
+
+func TestDecodeBin(t *testing.T) {
+	testDecodeBin(t, true)
+	testDecodeBin(t, false)
+}
+
+func testDecodeBin(t *testing.T, windows bool) {
+	b := bufWithBase("/bin/", windows)
+	key := make([]byte, 32)
+	for i := 0; i < 32; i++ {
+		key[i] = byte(i)
+	}
+
+	b.Write(key)
+
+	psk, err := DecodeV1PSK(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for i, b := range psk {
+		if b != psk[i] {
+			t.Fatal("byte was wrong")
+		}
+	}
+
+}