From 87df63f0ca9cf1df4f99f5818dad45bbc4c6e3e3 Mon Sep 17 00:00:00 2001 From: Carl Hetherington Date: Tue, 20 Apr 2021 22:53:46 +0200 Subject: [PATCH] Fix fopen() on windows to cope with long filenames (part of #1755). --- src/lib/cross.h | 1 + src/lib/cross_linux.cc | 8 +++++ src/lib/cross_osx.cc | 7 ++++ src/lib/cross_windows.cc | 35 +++++++++++++++++-- src/lib/util.cc | 1 + test/windows_test.cc | 72 ++++++++++++++++++++++++++++++++++++++++ test/wscript | 1 + 7 files changed, 123 insertions(+), 2 deletions(-) create mode 100644 test/windows_test.cc diff --git a/src/lib/cross.h b/src/lib/cross.h index cc066488a..bdcae3537 100644 --- a/src/lib/cross.h +++ b/src/lib/cross.h @@ -67,6 +67,7 @@ extern bool running_32_on_64 (); extern void unprivileged (); extern boost::filesystem::path config_path (); extern boost::filesystem::path directory_containing_executable (); +extern boost::filesystem::path fix_long_path (boost::filesystem::path path); namespace dcpomatic { std::string get_process_id (); } diff --git a/src/lib/cross_linux.cc b/src/lib/cross_linux.cc index 510bce8c3..816573230 100644 --- a/src/lib/cross_linux.cc +++ b/src/lib/cross_linux.cc @@ -420,3 +420,11 @@ dcpomatic::get_process_id () { return dcp::raw_convert(getpid()); } + + +boost::filesystem::path +fix_long_path (boost::filesystem::path path) +{ + return path; +} + diff --git a/src/lib/cross_osx.cc b/src/lib/cross_osx.cc index fc8ccd4a8..bd31541c5 100644 --- a/src/lib/cross_osx.cc +++ b/src/lib/cross_osx.cc @@ -607,3 +607,10 @@ dcpomatic::get_process_id () { return dcp::raw_convert(getpid()); } + + +boost::filesystem::path +fix_long_path (boost::filesystem::path path) +{ + return path; +} diff --git a/src/lib/cross_windows.cc b/src/lib/cross_windows.cc index 04ee26271..d97550ca9 100644 --- a/src/lib/cross_windows.cc +++ b/src/lib/cross_windows.cc @@ -26,6 +26,7 @@ #include "config.h" #include "exceptions.h" #include "dcpomatic_assert.h" +#include "util.h" #include #include extern "C" { @@ -234,6 +235,36 @@ disk_writer_path () #endif +/** Windows can't "by default" cope with paths longer than 260 characters, so if you pass such a path to + * any boost::filesystem method it will fail. There is a "fix" for this, which is to prepend + * the string \\?\ to the path. This will make it work, so long as: + * - the path is absolute. + * - the path only uses backslashes. + * - individual path components are "short enough" (probably less than 255 characters) + * + * See https://www.boost.org/doc/libs/1_57_0/libs/filesystem/doc/reference.html under + * "Warning: Long paths on Windows" for some details. + * + * Our fopen_boost uses this method to get this fix, but any other calls to boost::filesystem + * will not unless this method is explicitly called to pre-process the pathname. + */ +boost::filesystem::path +fix_long_path (boost::filesystem::path long_path) +{ + using namespace boost::filesystem; + path fixed = "\\\\?\\"; + /* We have to make the path canonical but we can't call canonical() on the long path + * as it will fail. So we'll sort of do it ourselves (possibly badly). + */ + if (long_path.is_absolute()) { + fixed += long_path.make_preferred(); + } else { + fixed += boost::filesystem::current_path() / long_path.make_preferred(); + } + return fixed; +} + + /* Apparently there is no way to create an ofstream using a UTF-8 filename under Windows. We are hence reduced to using fopen with this wrapper. @@ -242,8 +273,8 @@ FILE * fopen_boost (boost::filesystem::path p, string t) { wstring w (t.begin(), t.end()); - /* c_str() here should give a UTF-16 string */ - return _wfopen (p.c_str(), w.c_str ()); + /* c_str() on fixed here should give a UTF-16 string */ + return _wfopen (fix_long_path(p).c_str(), w.c_str()); } diff --git a/src/lib/util.cc b/src/lib/util.cc index 65bfd4534..8a039764d 100644 --- a/src/lib/util.cc +++ b/src/lib/util.cc @@ -1193,3 +1193,4 @@ start_of_thread (string) } #endif + diff --git a/test/windows_test.cc b/test/windows_test.cc new file mode 100644 index 000000000..4d07d5fdf --- /dev/null +++ b/test/windows_test.cc @@ -0,0 +1,72 @@ +/* + Copyright (C) 2021 Carl Hetherington + + This file is part of DCP-o-matic. + + DCP-o-matic is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + DCP-o-matic is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with DCP-o-matic. If not, see . + +*/ + + +#include "lib/cross.h" +#include "lib/util.h" +#include +#include +#include + + +BOOST_AUTO_TEST_CASE (fix_long_path_test) +{ +#ifdef DCPOMATIC_WINDOWS + BOOST_CHECK_EQUAL (fix_long_path("c:\\foo"), "\\\\?\\c:\\foo"); + BOOST_CHECK_EQUAL (fix_long_path("c:\\foo\\bar"), "\\\\?\\c:\\foo\\bar"); + boost::filesystem::path fixed_bar = "\\\\?\\"; + fixed_bar += boost::filesystem::current_path(); + fixed_bar /= "bar"; + BOOST_CHECK_EQUAL (fix_long_path("bar"), fixed_bar); +#else + BOOST_CHECK_EQUAL (fix_long_path("foo/bar/baz"), "foo/bar/baz"); +#endif +} + + +#ifdef DCPOMATIC_WINDOWS +BOOST_AUTO_TEST_CASE (windows_long_filename_test) +{ + using namespace boost::filesystem; + + path too_long = current_path() / "build\\test\\a\\really\\very\\long\\filesystem\\path\\indeed\\that\\will\\be\\so\\long\\that\\windows\\cannot\\normally\\cope\\with\\it\\unless\\we\\add\\this\\crazy\\prefix\\and\\then\\magically\\it\\can\\do\\it\\fine\\I\\dont\\really\\know\\why\\its\\like\\that\\but\\hey\\it\\is\\so\\here\\we\\are\\what\\can\\we\\do\\other\\than\\bodge\\it"; + + BOOST_CHECK (too_long.string().length() > 260); + boost::system::error_code ec; + create_directories (too_long, ec); + BOOST_CHECK (ec); + + path fixed_path = fix_long_path(too_long); + create_directories (fixed_path, ec); + BOOST_CHECK (!ec); + + auto file = fopen_boost(too_long / "hello", "w"); + BOOST_REQUIRE (file); + fprintf (file, "Hello_world"); + fclose (file); + + file = fopen_boost(too_long / "hello", "r"); + BOOST_REQUIRE (file); + char buffer[64]; + fscanf (file, "%63s", buffer); + BOOST_CHECK_EQUAL (strcmp(buffer, "Hello_world"), 0); +} +#endif + diff --git a/test/wscript b/test/wscript index 4303db835..e2628ecd8 100644 --- a/test/wscript +++ b/test/wscript @@ -138,6 +138,7 @@ def build(bld): video_level_test.cc video_mxf_content_test.cc vf_kdm_test.cc + windows_test.cc writer_test.cc zipper_test.cc """ -- 2.30.2