pkg/email: add function that forms reply to an email

3 files changed, 132 insertions, 1 deletions

diff --git a/pkg/email/parser.go b/pkg/email/parser.go
index 42a890472..a764a5826 100644
--- a/pkg/email/parser.go
+++ b/pkg/email/parser.go
@@ -27,6 +27,8 @@ type Email struct {
 	CommandArgs []string // arguments for the command
 }
 
+const commandPrefix = "#syzbot "
+
 func Parse(r io.Reader, ownEmail string) (*Email, error) {
 	msg, err := mail.ReadMessage(r)
 	if err != nil {
@@ -112,7 +114,7 @@ func extractBugID(from, canonical string) string {
 // Commands are of the following form:
 // ^#syzbot cmd args...
 func extractCommand(body []byte) (cmd string, args []string) {
-	cmdPos := bytes.Index(append([]byte{'\n'}, body...), []byte("\n#syzbot "))
+	cmdPos := bytes.Index(append([]byte{'\n'}, body...), []byte("\n"+commandPrefix))
 	if cmdPos == -1 {
 		return
 	}
diff --git a/pkg/email/reply.go b/pkg/email/reply.go
new file mode 100644
index 000000000..65aec4509
--- /dev/null
+++ b/pkg/email/reply.go
@@ -0,0 +1,42 @@
+// Copyright 2017 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package email
+
+import (
+	"bufio"
+	"bytes"
+	"strings"
+)
+
+func FormReply(email, reply string) string {
+	s := bufio.NewScanner(strings.NewReader(email))
+	out := new(bytes.Buffer)
+	replied := false
+	for s.Scan() {
+		ln := s.Bytes()
+		out.WriteByte('>')
+		if len(ln) != 0 && ln[0] != '>' {
+			out.WriteByte(' ')
+		}
+		out.Write(ln)
+		out.WriteByte('\n')
+		if !replied && bytes.HasPrefix(ln, []byte(commandPrefix)) {
+			replied = true
+			writeReply(out, reply)
+		}
+	}
+	if !replied {
+		writeReply(out, reply)
+	}
+	return out.String()
+}
+
+func writeReply(out *bytes.Buffer, reply string) {
+	out.WriteByte('\n')
+	out.WriteString(reply)
+	if reply != "" && reply[len(reply)-1] != '\n' {
+		out.WriteByte('\n')
+	}
+	out.WriteByte('\n')
+}
diff --git a/pkg/email/reply_test.go b/pkg/email/reply_test.go
new file mode 100644
index 000000000..2dd9d894d
--- /dev/null
+++ b/pkg/email/reply_test.go
@@ -0,0 +1,87 @@
+// Copyright 2017 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package email
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestFormReply(t *testing.T) {
+	for i, test := range formReplyTests {
+		t.Run(fmt.Sprint(i), func(t *testing.T) {
+			result := FormReply(test.email, test.reply)
+			if test.result != result {
+				t.Logf("expect:\n%s", test.result)
+				t.Logf("got:\n%s", result)
+				t.Fail()
+			}
+		})
+	}
+}
+
+var formReplyTests = []struct {
+	email  string
+	reply  string
+	result string
+}{
+	{
+		email: `line1
+line2
+#syzbot foo
+line3
+`,
+		reply: "this is reply",
+		result: `> line1
+> line2
+> #syzbot foo
+
+this is reply
+
+> line3
+`,
+	},
+	{
+		email: `> line1
+> line2
+#syzbot foo
+line3
+`,
+		reply: "this is reply\n",
+		result: `>> line1
+>> line2
+> #syzbot foo
+
+this is reply
+
+> line3
+`,
+	},
+	{
+		email: `line1
+line2
+#syzbot foo`,
+		reply: "this is reply 1\nthis is reply 2",
+		result: `> line1
+> line2
+> #syzbot foo
+
+this is reply 1
+this is reply 2
+
+`,
+	},
+	{
+		email: `line1
+line2
+`,
+		reply: "this is reply",
+		result: `> line1
+> line2
+
+this is reply
+
+`,
+	},
+}