[2023-09-17 21:51] David Levine
> > A format-patch is attached.
>
> Thanks. I think that the commit message should note that only header field
> bodies are folded. And because folding can only occur a
> t whitespace, it is possible to end up with more than 78 bytes in a line.
> How about this?
>
> mhbuild now folds header field bodies to avoid lines with more then 78
> bytes.
>
> This is required by RFC 5322 2.1.1. Line Length Limits.
>
> I'll add the first line of the commit message to docs/pending-release-notes.
> And add the year to the copyright notice in fold.[hc].
Done, updated version is attached.
Philipp
From 3157510d821db9bf62b051aeb1dcc94fac1dffcd Mon Sep 17 00:00:00 2001
From: Philipp Takacs
Date: Fri, 25 Aug 2023 09:29:42 +0200
Subject: [PATCH] mhbuild implement header folding
mhbuild now folds header field bodies to avoid lines with more then 78 bytes.
This is required by RFC 5322 2.1.1. Line Length Limits.
---
Makefile.am | 2 ++
sbr/fold.c| 63 +++
sbr/fold.h| 7 +
test/mhbuild/test-mhbuild | 53
uip/mhoutsbr.c| 7 -
5 files changed, 131 insertions(+), 1 deletion(-)
create mode 100644 sbr/fold.c
create mode 100644 sbr/fold.h
diff --git a/Makefile.am b/Makefile.am
index 4fc84c1d..168d9fe6 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -378,6 +378,7 @@ noinst_HEADERS = \
sbr/fmt_new.h \
sbr/fmt_rfc2047.h \
sbr/fmt_scan.h \
+sbr/fold.h \
sbr/folder_addmsg.h \
sbr/folder_delmsgs.h \
sbr/folder_free.h \
@@ -1106,6 +1107,7 @@ sbr_libmh_a_SOURCES = \
sbr/fmt_new.c \
sbr/fmt_rfc2047.c \
sbr/fmt_scan.c \
+sbr/fold.c \
sbr/folder_addmsg.c \
sbr/folder_delmsgs.c \
sbr/folder_free.c \
diff --git a/sbr/fold.c b/sbr/fold.c
new file mode 100644
index ..f6047703
--- /dev/null
+++ b/sbr/fold.c
@@ -0,0 +1,63 @@
+/* fold.c -- fold a mail header field
+ *
+ * This code is Copyright (c) 2023, by the authors of nmh. See the
+ * COPYRIGHT file in the root directory of the nmh distribution for
+ * complete copyright information. */
+
+#include "h/mh.h"
+#include "h/mime.h"
+#include "sbr/charstring.h"
+#include "fold.h"
+
+void
+fold(charstring_t dst, size_t namelen, const char *restrict body)
+{
+ const char *restrict body_next;
+ const char *restrict wsp;
+ const char *restrict wsp_next;
+ const bool crlf = strchr(body, '\r');
+ charstring_clear(dst);
+ namelen++;
+
+ while (*body) {
+ body_next = strchr(body, '\n');
+ if ((unsigned long) (body_next - body) <= MAXTEXTPERLN - namelen) {
+ charstring_push_back_chars(dst, body, body_next - body + 1, body_next - body + 1);
+ namelen = 0;
+ body = body_next + 1;
+ continue;
+ }
+ wsp = body;
+ while (namelen == 0 && (*wsp == ' ' || *wsp == '\t')) {
+ wsp++;
+ }
+ wsp = wsp_next = strpbrk(wsp, " \t");
+
+ /* if now whitespace is in the current line just print the curret line as is */
+ if (!wsp_next || wsp_next > body_next) {
+ charstring_push_back_chars(dst, body, body_next - body + 1, body_next - body + 1);
+ namelen = 0;
+ body = body_next + 1;
+ continue;
+ }
+
+ while ((unsigned long)(wsp_next - body) <= MAXTEXTPERLN - namelen) {
+ wsp = wsp_next;
+ wsp_next = strpbrk(wsp+1, " \t");
+ if (!wsp_next) {
+break;
+ }
+ if (wsp_next > body_next) {
+break;
+ }
+ }
+
+ charstring_push_back_chars(dst, body, wsp - body, wsp - body);
+ if (crlf) {
+ charstring_push_back(dst, '\r');
+ }
+ charstring_push_back(dst, '\n');
+ namelen = 0;
+ body = wsp;
+ }
+}
diff --git a/sbr/fold.h b/sbr/fold.h
new file mode 100644
index ..40bf6a49
--- /dev/null
+++ b/sbr/fold.h
@@ -0,0 +1,7 @@
+/* fold.h -- fold a mail header field
+ *
+ * This code is Copyright (c) 2023, by the authors of nmh. See the
+ * COPYRIGHT file in the root directory of the nmh distribution for
+ * complete copyright information. */
+
+void fold(charstring_t dst, size_t namelen, const char *restrict body);
diff --git a/test/mhbuild/test-mhbuild b/test/mhbuild/test-mhbuild
index 706a804a..f8d4992b 100755
--- a/test/mhbuild/test-mhbuild
+++ b/test/mhbuild/test-mhbuild
@@ -221,5 +221,58 @@ run_test "mhbuild $f" \
check "$f" "$expected"
+start_test "Checking for correct header folding"
+
+cat >"`mhpath new`" <<\E
+From: Somebody
+To: Nobody
+Subject: Test message
+References:
+
+This is a test
+E
+
+cat > "$expected" <<\E
+From: Somebody
+To: Nobody
+Subject: Test message
+References:
+
+MIME-Version: 1.0
+Content-Type: text/plain; charset="us-ascii"
+
+This is a test
+E
+
+run_test "mhbuild -auto `mhpath last`"
+check "`mhpath last`" "$expected"
+
+start_test "Checking header folding with a to long line"
+
+cat >"`mhpath new`" <<\E
+From: Somebody
+To: Nobody
+Subject: Test message
+References:
+
+This is a test
+E
+
+cat > "$expected" <<\E
+From: Somebody
+To: Nobody
+Subject: Tes
