mbox: extract formatting into a shared package

Move the mbox generation logic out of pkg/web into a new pkg/mbox
package so that both the web and API layers can use it. Replace the
hand-rolled header parsing and formatting with go-mbox and go-message
libraries: textproto.ReadHeader to parse stored headers,
textproto.WriteHeader for output, mail.Address for address formatting,
and mbox.Writer for the envelope framing. Normalize the body to CRLF
line endings.

Signed-off-by: Robin Jarry <robin@jarry.cc>

Author: rjarry

pkg/mbox/mbox.go

@@ -0,0 +1,214 @@
+// Patchwork - automated patch tracking system
+// Copyright (C) The Patchwork Contributors (see CONTRIBUTORS)
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package mbox
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/emersion/go-mbox"
+	"github.com/emersion/go-message/mail"
+	"github.com/emersion/go-message/textproto"
+	"github.com/uptrace/bun"
+
+	"github.com/getpatchwork/patchwork/pkg/db"
+	"github.com/getpatchwork/patchwork/pkg/log"
+)
+
+var (
+	postscriptRe   = regexp.MustCompile(`(?m)^-{2,3} ?$`)
+	mboxResponseRe = regexp.MustCompile(`(?mi)^(Tested|Reviewed|Acked|Signed-off|Nacked|Reported)-by:.*$`)
+	safeFilenameRe = regexp.MustCompile(`[^a-z0-9_.-]+`)
+)
+
+type Submission struct {
+	ID              int
+	Date            time.Time
+	Content         string
+	Diff            string
+	Headers         string
+	Submitter       mail.Address
+	DelegateEmail   string
+	ListEmail       string
+	CommentContents []string
+}
+
+func Format(sub Submission) []byte {
+	h, err := textproto.ReadHeader(bufio.NewReader(
+		strings.NewReader(sub.Headers + "\n")))
+	if err != nil {
+		log.Errorf("textproto.ReadHeader: %v", err)
+		h = textproto.Header{}
+	}
+
+	if fromVal := h.Get("From"); fromVal != "" {
+		fromAddr, err := mail.ParseAddress(fromVal)
+		if err == nil && fromAddr.Address == sub.ListEmail {
+			h.Set("X-Patchwork-Original-From", fromVal)
+			h.Set("From", sub.Submitter.String())
+		}
+	}
+	if !h.Has("Date") {
+		h.Set("Date", sub.Date.UTC().Format(time.RFC1123Z))
+	}
+	h.Set("X-Patchwork-Submitter", sub.Submitter.String())
+	h.Set("X-Patchwork-Id", strconv.Itoa(sub.ID))
+	if sub.Diff != "" && sub.DelegateEmail != "" {
+		h.Set("X-Patchwork-Delegate", sub.DelegateEmail)
+	}
+	h.Set("Content-Type", "text/plain; charset=utf-8")
+	h.Set("Content-Transfer-Encoding", "8bit")
+
+	var buf bytes.Buffer
+
+	mw := mbox.NewWriter(&buf)
+
+	w, err := mw.CreateMessage("patchwork", sub.Date)
+	if err != nil {
+		log.Errorf("mbox.CreateMessage: %v", err)
+		return nil
+	}
+
+	if err := textproto.WriteHeader(w, h); err != nil {
+		log.Errorf("textproto.WriteHeader: %v", err)
+		return nil
+	}
+
+	body := ""
+	if sub.Content != "" {
+		body = strings.TrimSpace(sub.Content) + "\n"
+	}
+
+	postscript := ""
+	if loc := postscriptRe.FindStringIndex(body); loc != nil {
+		postscript = body[loc[1]:]
+		body = strings.TrimSpace(body[:loc[0]]) + "\n"
+		postscript = strings.TrimRight(postscript, " \t\n")
+	}
+
+	for _, content := range sub.CommentContents {
+		for _, m := range mboxResponseRe.FindAllString(content, -1) {
+			body += m + "\n"
+		}
+	}
+
+	if postscript != "" {
+		body += "---" + postscript + "\n"
+	} else if sub.Diff != "" {
+		body += "---\n"
+	}
+
+	if sub.Diff != "" {
+		body += "\n" + sub.Diff
+	}
+
+	sc := bufio.NewScanner(strings.NewReader(body))
+	for sc.Scan() {
+		fmt.Fprintf(w, "%s\r\n", sc.Text())
+	}
+	mw.Close()
+
+	return buf.Bytes()
+}
+
+func SanitizeFilename(name string) string {
+	s := strings.ToLower(name)
+	s = safeFilenameRe.ReplaceAllString(s, "-")
+	s = strings.Trim(s, "-")
+	s = strings.Trim(s, "-")
+	if s == "" {
+		s = "patch"
+	}
+	return s
+}
+
+func BuildPatchSubmission(
+	ctx context.Context, idb bun.IDB, patch *db.Patch, listEmail string,
+) Submission {
+	sub := Submission{
+		ID:        patch.ID,
+		Date:      patch.Date,
+		Headers:   patch.Headers,
+		ListEmail: listEmail,
+	}
+	if patch.Content != nil {
+		sub.Content = *patch.Content
+	}
+	if patch.Diff != nil {
+		sub.Diff = *patch.Diff
+	}
+
+	var submitter db.Person
+	if idb.NewSelect().Model(&submitter).
+		Where("id = ?", patch.SubmitterID).
+		Scan(ctx) == nil {
+		sub.Submitter.Address = submitter.Email
+		if submitter.Name != nil {
+			sub.Submitter.Name = *submitter.Name
+		}
+	}
+
+	if patch.DelegateID != nil {
+		var delegate db.User
+		if idb.NewSelect().Model(&delegate).
+			Where("id = ?", *patch.DelegateID).
+			Scan(ctx) == nil {
+			sub.DelegateEmail = delegate.Email
+		}
+	}
+
+	var contents []string
+	if err := idb.NewSelect().
+		Model((*db.PatchComment)(nil)).Column("content").
+		Where("patch_id = ?", patch.ID).OrderExpr("date ASC").
+		Scan(ctx, &contents); err != nil {
+		log.Errorf("load patch comments: %v", err)
+	}
+	sub.CommentContents = contents
+
+	return sub
+}
+
+func BuildCoverSubmission(
+	ctx context.Context, idb bun.IDB, cover *db.Cover, listEmail string,
+) Submission {
+	sub := Submission{
+		ID:        cover.ID,
+		Date:      cover.Date,
+		Headers:   cover.Headers,
+		ListEmail: listEmail,
+	}
+	if cover.Content != nil {
+		sub.Content = *cover.Content
+	}
+
+	var submitter db.Person
+	if idb.NewSelect().Model(&submitter).
+		Where("id = ?", cover.SubmitterID).
+		Scan(ctx) == nil {
+		sub.Submitter.Address = submitter.Email
+		if submitter.Name != nil {
+			sub.Submitter.Name = *submitter.Name
+		}
+	}
+
+	var contents []string
+	if err := idb.NewSelect().
+		Model((*db.CoverComment)(nil)).Column("content").
+		Where("cover_id = ?", cover.ID).OrderExpr("date ASC").
+		Scan(ctx, &contents); err != nil {
+		log.Errorf("load cover comments: %v", err)
+	}
+	sub.CommentContents = contents
+
+	return sub
+}