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[PATCH v2 3/7] format-patch: do not wrap rfc2047 encoded headers too late

From
JSJan H. Schönherr <schnhrr@cs.tu-berlin.de>
Date
Oct 18, 2012, 14:43 UTC
Message-ID
<1350571414-17907-4-git-send-email-schnhrr@cs.tu-berlin.de>
In-Reply-To
<1350571414-17907-1-git-send-email-schnhrr@cs.tu-berlin.de>
From: Jan H. Schönherr <schnhrr@cs.tu-berlin.de>

Encoded characters add more than one character at once to an encoded header. Include all characters that are about to be added in the length calculation for wrapping.

Additionally, RFC 2047 imposes a maximum line length of 76 characters if that line contains an rfc2047 encoded word.

Signed-off-by: Jan H. Schönherr <schnhrr@cs.tu-berlin.de>
---
v2:
- use constants for both, the 76 and 78 char limit
- rephrase comment
---
 pretty.c                | 26 +++++++++++++---------
 t/t4014-format-patch.sh | 58 +++++++++++++++++++++++++++++--------------------
 2 Dateien geändert, 51 Zeilen hinzugefügt(+), 33 Zeilen entfernt(-)
diff --git a/pretty.c b/pretty.c
index 71e4024..da75879 100644
--- a/pretty.c
+++ b/pretty.c
@@ -263,6 +263,9 @@ static void add_rfc822_quoted(struct strbuf *out, const char *s, int len)
 
 static int is_rfc2047_special(char ch)
 {
+	if (ch == ' ' || ch == '\n')
+		return 1;
+
 	return (non_ascii(ch) || (ch == '=') || (ch == '?') || (ch == '_'));
 }
 
@@ -270,6 +273,7 @@ static void add_rfc2047(struct strbuf *sb, const char *line, int len,
 		       const char *encoding)
 {
 	static const int max_length = 78; /* per rfc2822 */
+	static const int max_encoded_length = 76; /* per rfc2047 */
 	int i;
 	int line_len;
 
@@ -295,23 +299,25 @@ needquote:
 	line_len += strlen(encoding) + 5; /* 5 for =??q? */
 	for (i = 0; i < len; i++) {
 		unsigned ch = line[i] & 0xFF;
+		int is_special = is_rfc2047_special(ch);
+
+		/*
+		 * According to RFC 2047, we could encode the special character
+		 * ' ' (space) with '_' (underscore) for readability. But many
+		 * programs do not understand this and just leave the
+		 * underscore in place. Thus, we do nothing special here, which
+		 * causes ' ' to be encoded as '=20', avoiding this problem.
+		 */
 
-		if (line_len >= max_length - 2) {
+		if (line_len + 2 + (is_special ? 3 : 1) > max_encoded_length) {
 			strbuf_addf(sb, "?=\n =?%s?q?", encoding);
 			line_len = strlen(encoding) + 5 + 1; /* =??q? plus SP */
 		}
 
-		/*
-		 * We encode ' ' using '=20' even though rfc2047
-		 * allows using '_' for readability.  Unfortunately,
-		 * many programs do not understand this and just
-		 * leave the underscore in place.
-		 */
-		if (is_rfc2047_special(ch) || ch == ' ' || ch == '\n') {
+		if (is_special) {
 			strbuf_addf(sb, "=%02X", ch);
 			line_len += 3;
-		}
-		else {
+		} else {
 			strbuf_addch(sb, ch);
 			line_len++;
 		}
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index d66e358..1d5636d 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -772,30 +772,31 @@ M8="föö bar "
 M64=$M8$M8$M8$M8$M8$M8$M8$M8
 M512=$M64$M64$M64$M64$M64$M64$M64$M64
 cat >expect <<'EOF'
-Subject: [PATCH] =?UTF-8?q?f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
- =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar?=
+Subject: [PATCH] =?UTF-8?q?f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f?=
+ =?UTF-8?q?=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar?=
+ =?UTF-8?q?=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20?=
+ =?UTF-8?q?bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6?=
+ =?UTF-8?q?=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3?=
+ =?UTF-8?q?=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
+ =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3?=
+ =?UTF-8?q?=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f?=
+ =?UTF-8?q?=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar?=
+ =?UTF-8?q?=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20?=
+ =?UTF-8?q?bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6?=
+ =?UTF-8?q?=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3?=
+ =?UTF-8?q?=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
+ =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3?=
+ =?UTF-8?q?=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f?=
+ =?UTF-8?q?=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar?=
+ =?UTF-8?q?=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20?=
+ =?UTF-8?q?bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6?=
+ =?UTF-8?q?=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3?=
+ =?UTF-8?q?=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6?=
+ =?UTF-8?q?=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3?=
+ =?UTF-8?q?=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar=20f?=
+ =?UTF-8?q?=C3=B6=C3=B6=20bar=20f=C3=B6=C3=B6=20bar?=
 EOF
-test_expect_success 'format-patch wraps extremely long headers (rfc2047)' '
+test_expect_success 'format-patch wraps extremely long subject (rfc2047)' '
 	rm -rf patches/ &&
 	echo content >>file &&
 	git add file &&
@@ -862,6 +863,17 @@ test_expect_success 'format-patch wraps extremely long from-header (rfc822)' '
 '
 
 cat >expect <<'EOF'
+From: =?UTF-8?q?Fo=C3=B6=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo?=
+ =?UTF-8?q?=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20?=
+ =?UTF-8?q?Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar?=
+ =?UTF-8?q?=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20Foo=20Bar=20?=
+ =?UTF-8?q?Foo=20Bar=20Foo=20Bar?= <author@example.com>
+EOF
+test_expect_success 'format-patch wraps extremely long from-header (rfc2047)' '
+	check_author "Foö Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar"
+'
+
+cat >expect <<'EOF'
 Subject: header with . in it
 EOF
 test_expect_success 'subject lines do not have 822 atom-quoting' '

-- 
1.7.12
Previous: Jan H. SchönherrNext: Jan H. Schönherr
Message 4 of 8 in “Cure some format-patch wrapping and encoding issues”
  1. 0/7 Cure some format-patch wrapping and encoding issuesJan H. Schönherr, Oct 18, 2012
  2. 1/7 utf8: fix off-by-one wrapping of textJan H. Schönherr, Oct 18, 2012
  3. 2/7 format-patch: do not wrap non-rfc2047 headers too earlyJan H. Schönherr, Oct 18, 2012
  4. 3/7 format-patch: do not wrap rfc2047 encoded headers too lateJan H. Schönherr, Oct 18, 2012
  5. 4/7 format-patch: introduce helper function last_line_length()Jan H. Schönherr, Oct 18, 2012
  6. 5/7 format-patch: make rfc2047 encoding more strictJan H. Schönherr, Oct 18, 2012
  7. 6/7 format-patch: fix rfc2047 address encoding with respect to rfc822 specialsJan H. Schönherr, Oct 18, 2012
  8. 7/7 format-patch tests: check quoting/encoding in To: and Cc: headersJan H. Schönherr, Oct 18, 2012

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