From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id DD0F51F453 for ; Sat, 9 Feb 2019 20:08:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726873AbfBIUIT (ORCPT ); Sat, 9 Feb 2019 15:08:19 -0500 Received: from injection.crustytoothpaste.net ([192.241.140.119]:34004 "EHLO injection.crustytoothpaste.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726836AbfBIUIT (ORCPT ); Sat, 9 Feb 2019 15:08:19 -0500 Received: from genre.crustytoothpaste.net (unknown [IPv6:2001:470:b978:101:d42:63e7:5548:1ee8]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by injection.crustytoothpaste.net (Postfix) with ESMTPSA id 7826F60737; Sat, 9 Feb 2019 20:08:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=crustytoothpaste.net; s=default; t=1549742896; bh=9LVKoqKzzq50MAOLT5jI4t2rUjK3uJlUYy3EKf00HJk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Reply-To: Subject:Date:To:CC:Resent-Date:Resent-From:Resent-To:Resent-Cc: In-Reply-To:References:Content-Type:Content-Disposition; b=cCXT0BkkPJfNtZN58J+ZyXyQ0G14EEe65jZwWXIHbcTP03q5ASlqWDbr9GBWR7cem J/ejUax3kwhFo6jok/6cvepC+uLqUa6fHUwc/1yz8heogyOrJ1VnmfOn6CCUWRMk79 VZHXTND+veBZNPZjXOm+edocdhZRwA5HeufcqkrHpbz+HiQsaY6UjOdgD8mCjEFx0H Kdxg6KwG07ejznUOYU3WuJz64FgsrBnH94lXWeF2OAglNJZIPXzdd2TYWkBdBo5bWF eQ8vIqPp5gH8R9SiN7D8YRIuctBGnwf/XhoSQOMoHNGNXs3CS0HvkwP/YUMHwQodBf VquShHqQIr99Qr+tvWJgnLNX3ouW3Jc2gCMmti6oOWsQ+cS0yWm7xuaKGS3NCMpi7+ Hvuk7gFZwkSnwgK3a8/gBISJunHU/Dw7ACrAQtUwFpZJPPyS1FuBhPY7UpvgTnYVOd tO5lfg4pz6R87RA2qsgkNRLaJcHgaPBuuZq4mEkx6JNsQilH7+x From: "brian m. carlson" To: git@vger.kernel.org Cc: larsxschneider@gmail.com, Rich Felker , Junio C Hamano , Kevin Daudt Subject: [PATCH] utf8: handle systems that don't write BOM for UTF-16 Date: Sat, 9 Feb 2019 20:08:01 +0000 Message-Id: <20190209200802.277139-1-sandals@crustytoothpaste.net> X-Mailer: git-send-email 2.20.1.791.gb4d0f1c61a In-Reply-To: <20190209145732.GA14229@alpha> References: <20190209145732.GA14229@alpha> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 127.0.1.1 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org When serializing UTF-16 (and UTF-32), there are three possible ways to write the stream. One can write the data with a BOM in either big-endian or little-endian format, or one can write the data without a BOM in big-endian format. Most systems' iconv implementations choose to write it with a BOM in some endianness, since this is the most foolproof, and it is resistant to misinterpretation on Windows, where UTF-16 and the little-endian serialization are very common. For compatibility with Windows and to avoid accidental misuse there, Git always wants to write UTF-16 with a BOM, and will refuse to read UTF-16 without it. However, musl's iconv implementation writes UTF-16 without a BOM, relying on the user to interpret it as big-endian. This causes t0028 and the related functionality to fail, since Git won't read the file without a BOM. Add a Makefile and #define knob, ICONV_NEEDS_BOM, that can be set if the iconv implementation has this behavior. When set, Git will write a BOM manually for UTF-16 and UTF-32 and then force the data to be written in UTF-16BE or UTF-32BE. We choose big-endian behavior here because the tests use the raw "UTF-16" encoding, which will be big-endian when the implementation requires this knob to be set. Update the tests to detect this case and write test data with an added BOM if necessary. Always write the BOM in the tests in big-endian format, since all iconv implementations that omit a BOM must use big-endian serialization according to the Unicode standard. Preserve the existing behavior for systems which do not have this knob enabled, since they may use optimized implementations, including defaulting to the native endianness, to gain improved performance, which can be significant with large checkouts. Signed-off-by: brian m. carlson --- Makefile | 6 ++++++ t/t0028-working-tree-encoding.sh | 25 ++++++++++++++++++++++--- utf8.c | 10 ++++++++++ 3 files changed, 38 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index 571160a2c4..b2a4765e5f 100644 --- a/Makefile +++ b/Makefile @@ -259,6 +259,9 @@ all:: # Define OLD_ICONV if your library has an old iconv(), where the second # (input buffer pointer) parameter is declared with type (const char **). # +# Define ICONV_NEEDS_BOM if your iconv implementation does not write a +# byte-order mark (BOM) when writing UTF-16 or UTF-32. +# # Define NO_DEFLATE_BOUND if your zlib does not have deflateBound. # # Define NO_R_TO_GCC_LINKER if your gcc does not like "-R/path/lib" @@ -1415,6 +1418,9 @@ ifndef NO_ICONV EXTLIBS += $(ICONV_LINK) -liconv endif endif +ifdef ICONV_NEEDS_BOM + BASIC_CFLAGS += -DICONV_NEEDS_BOM +endif ifdef NEEDS_LIBGEN EXTLIBS += -lgen endif diff --git a/t/t0028-working-tree-encoding.sh b/t/t0028-working-tree-encoding.sh index e58ecbfc44..bfc4a9d4dd 100755 --- a/t/t0028-working-tree-encoding.sh +++ b/t/t0028-working-tree-encoding.sh @@ -6,6 +6,25 @@ test_description='working-tree-encoding conversion via gitattributes' GIT_TRACE_WORKING_TREE_ENCODING=1 && export GIT_TRACE_WORKING_TREE_ENCODING +test_lazy_prereq NO_UTF16_BOM ' + test $(printf abc | iconv -f UTF-8 -t UTF-16 | wc -c) = 6 +' + +test_lazy_prereq NO_UTF32_BOM ' + test $(printf abc | iconv -f UTF-8 -t UTF-32 | wc -c) = 12 +' + +write_utf16 () { + test_have_prereq NO_UTF16_BOM && printf '\xfe\xff' + iconv -f UTF-8 -t UTF-16 + +} + +write_utf32 () { + test_have_prereq NO_UTF32_BOM && printf '\x00\x00\xfe\xff' + iconv -f UTF-8 -t UTF-32 +} + test_expect_success 'setup test files' ' git config core.eol lf && @@ -13,8 +32,8 @@ test_expect_success 'setup test files' ' echo "*.utf16 text working-tree-encoding=utf-16" >.gitattributes && echo "*.utf16lebom text working-tree-encoding=UTF-16LE-BOM" >>.gitattributes && printf "$text" >test.utf8.raw && - printf "$text" | iconv -f UTF-8 -t UTF-16 >test.utf16.raw && - printf "$text" | iconv -f UTF-8 -t UTF-32 >test.utf32.raw && + printf "$text" | write_utf16 >test.utf16.raw && + printf "$text" | write_utf32 >test.utf32.raw && printf "\377\376" >test.utf16lebom.raw && printf "$text" | iconv -f UTF-8 -t UTF-32LE >>test.utf16lebom.raw && @@ -223,7 +242,7 @@ test_expect_success ICONV_SHIFT_JIS 'check roundtrip encoding' ' text="hallo there!\nroundtrip test here!" && printf "$text" | iconv -f UTF-8 -t SHIFT-JIS >roundtrip.shift && - printf "$text" | iconv -f UTF-8 -t UTF-16 >roundtrip.utf16 && + printf "$text" | write_utf16 >roundtrip.utf16 && echo "*.shift text working-tree-encoding=SHIFT-JIS" >>.gitattributes && # SHIFT-JIS encoded files are round-trip checked by default... diff --git a/utf8.c b/utf8.c index 83824dc2f4..133199de0e 100644 --- a/utf8.c +++ b/utf8.c @@ -568,6 +568,16 @@ char *reencode_string_len(const char *in, size_t insz, bom_str = utf16_be_bom; bom_len = sizeof(utf16_be_bom); out_encoding = "UTF-16BE"; +#ifdef ICONV_NEEDS_BOM + } else if (same_utf_encoding("UTF-16", out_encoding)) { + bom_str = utf16_be_bom; + bom_len = sizeof(utf16_be_bom); + out_encoding = "UTF-16BE"; + } else if (same_utf_encoding("UTF-32", out_encoding)) { + bom_str = utf32_be_bom; + bom_len = sizeof(utf32_be_bom); + out_encoding = "UTF-32BE"; +#endif } conv = iconv_open(out_encoding, in_encoding);