Merge #13878: utils: Add fstream wrapper to allow to pass unicode filename on Windows

43c7fbb1e79a4a2219306bf3da1a2dfdf9213f2c Make MSVC compiler read the source code using utf-8 (Chun Kuan Lee)
f86a571edb9627c126b9ccd7da68bd7d1657b8f8 tests: Add test case for std::ios_base::ate (Chun Kuan Lee)
a554cc901a32f41162089d6b20ad39d5aeff0583 Move boost/std fstream to fsbridge (Chun Kuan Lee)
86eb3b3f1ab594142b6baa9576717ff121f3b745 utils: Add fsbridge fstream function wrapper (Chun Kuan Lee)

Pull request description:

  If compiled with mingw, use glibc++ extension `stdio_filebuf` to open the file by `FILE*` instead of filename.

  In other condition, we can use boost::fstream.

Tree-SHA512: b5dbd83e347fb9b2a0c8b1c2c7bd71a272e839ec0617883b2a0ec12506ae9e825373cf6e95b9bcc91d7edc85bf51580a7716b56a9ecaad776bc3ae61638cb3da

1 files changed, 102 insertions, 0 deletions

diff --git a/src/fs.cpp b/src/fs.cpp
index df79b5e3df..a146107c4c 100644
--- a/src/fs.cpp
+++ b/src/fs.cpp
@@ -113,4 +113,106 @@ std::string get_filesystem_error_message(const fs::filesystem_error& e)
 #endif
 }
 
+#ifdef WIN32
+#ifdef __GLIBCXX__
+
+// reference: https://github.com/gcc-mirror/gcc/blob/gcc-7_3_0-release/libstdc%2B%2B-v3/include/std/fstream#L270
+
+static std::string openmodeToStr(std::ios_base::openmode mode)
+{
+    switch (mode & ~std::ios_base::ate) {
+    case std::ios_base::out:
+    case std::ios_base::out | std::ios_base::trunc:
+        return "w";
+    case std::ios_base::out | std::ios_base::app:
+    case std::ios_base::app:
+        return "a";
+    case std::ios_base::in:
+        return "r";
+    case std::ios_base::in | std::ios_base::out:
+        return "r+";
+    case std::ios_base::in | std::ios_base::out | std::ios_base::trunc:
+        return "w+";
+    case std::ios_base::in | std::ios_base::out | std::ios_base::app:
+    case std::ios_base::in | std::ios_base::app:
+        return "a+";
+    case std::ios_base::out | std::ios_base::binary:
+    case std::ios_base::out | std::ios_base::trunc | std::ios_base::binary:
+        return "wb";
+    case std::ios_base::out | std::ios_base::app | std::ios_base::binary:
+    case std::ios_base::app | std::ios_base::binary:
+        return "ab";
+    case std::ios_base::in | std::ios_base::binary:
+        return "rb";
+    case std::ios_base::in | std::ios_base::out | std::ios_base::binary:
+        return "r+b";
+    case std::ios_base::in | std::ios_base::out | std::ios_base::trunc | std::ios_base::binary:
+        return "w+b";
+    case std::ios_base::in | std::ios_base::out | std::ios_base::app | std::ios_base::binary:
+    case std::ios_base::in | std::ios_base::app | std::ios_base::binary:
+        return "a+b";
+    default:
+        return std::string();
+    }
+}
+
+void ifstream::open(const fs::path& p, std::ios_base::openmode mode)
+{
+    close();
+    m_file = fsbridge::fopen(p, openmodeToStr(mode).c_str());
+    if (m_file == nullptr) {
+        return;
+    }
+    m_filebuf = __gnu_cxx::stdio_filebuf<char>(m_file, mode);
+    rdbuf(&m_filebuf);
+    if (mode & std::ios_base::ate) {
+        seekg(0, std::ios_base::end);
+    }
+}
+
+void ifstream::close()
+{
+    if (m_file != nullptr) {
+        m_filebuf.close();
+        fclose(m_file);
+    }
+    m_file = nullptr;
+}
+
+void ofstream::open(const fs::path& p, std::ios_base::openmode mode)
+{
+    close();
+    m_file = fsbridge::fopen(p, openmodeToStr(mode).c_str());
+    if (m_file == nullptr) {
+        return;
+    }
+    m_filebuf = __gnu_cxx::stdio_filebuf<char>(m_file, mode);
+    rdbuf(&m_filebuf);
+    if (mode & std::ios_base::ate) {
+        seekp(0, std::ios_base::end);
+    }
+}
+
+void ofstream::close()
+{
+    if (m_file != nullptr) {
+        m_filebuf.close();
+        fclose(m_file);
+    }
+    m_file = nullptr;
+}
+#else // __GLIBCXX__
+
+static_assert(sizeof(*fs::path().BOOST_FILESYSTEM_C_STR) == sizeof(wchar_t),
+    "Warning: This build is using boost::filesystem ofstream and ifstream "
+    "implementations which will fail to open paths containing multibyte "
+    "characters. You should delete this static_assert to ignore this warning, "
+    "or switch to a different C++ standard library like the Microsoft C++ "
+    "Standard Library (where boost uses non-standard extensions to construct "
+    "stream objects with wide filenames), or the GNU libstdc++ library (where "
+    "a more complicated workaround has been implemented above).");
+
+#endif // __GLIBCXX__
+#endif // WIN32
+
 } // fsbridge