text: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  // Author: laszlocsomor@google.com (Laszlo Csomor)
  //  Based on original Protocol Buffers design by
  //  Sanjay Ghemawat, Jeff Dean, and others.
  
  // Implementation for long-path-aware open/mkdir/access/etc. on Windows, as well
  // as for the supporting utility functions.
  //
  // These functions convert the input path to an absolute Windows path
  // with "\\?\" prefix, then pass that to _wopen/_wmkdir/_waccess/etc.
  // (declared in <io.h>) respectively. This allows working with files/directories
  // whose paths are longer than MAX_PATH (260 chars).
  //
  // This file is only used on Windows, it's empty on other platforms.
  
  #if defined(_WIN32) && !defined(_XBOX_ONE)
  
  // Comment this out to fall back to using the ANSI versions (open, mkdir, ...)
  // instead of the Unicode ones (_wopen, _wmkdir, ...). Doing so can be useful to
  // debug failing tests if that's caused by the long path support.
  #define SUPPORT_LONGPATHS
  
  #include <google/protobuf/io/io_win32.h>
  
  #include <ctype.h>
  #include <direct.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <io.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #include <wctype.h>
  
  #ifndef WIN32_LEAN_AND_MEAN
  #define WIN32_LEAN_AND_MEAN 1
  #endif
  
  #include <windows.h>
  
  #include <memory>
  #include <sstream>
  #include <string>
  #include <vector>
  
  namespace google {
  namespace protobuf {
  namespace io {
  namespace win32 {
  namespace {
  
  using std::string;
  using std::wstring;
  
  template <typename char_type>
  struct CharTraits {
    static bool is_alpha(char_type ch);
  };
  
  template <>
  struct CharTraits<char> {
    static bool is_alpha(char ch) { return isalpha(ch); }
  };
  
  template <>
  struct CharTraits<wchar_t> {
    static bool is_alpha(wchar_t ch) { return iswalpha(ch); }
  };
  
  template <typename char_type>
  bool null_or_empty(const char_type* s) {
    return s == nullptr || *s == 0;
  }
  
  // Returns true if the path starts with a drive letter, e.g. "c:".
  // Note that this won't check for the "\" after the drive letter, so this also
  // returns true for "c:foo" (which is "c:\${PWD}\foo").
  // This check requires that a path not have a longpath prefix ("\\?\").
  template <typename char_type>
  bool has_drive_letter(const char_type* ch) {
    return CharTraits<char_type>::is_alpha(ch[0]) && ch[1] == ':';
  }
  
  // Returns true if the path starts with a longpath prefix ("\\?\").
  template <typename char_type>
  bool has_longpath_prefix(const char_type* path) {
    return path[0] == '\\' && path[1] == '\\' && path[2] == '?' &&
           path[3] == '\\';
  }
  
  template <typename char_type>
  bool is_separator(char_type c) {
    return c == '/' || c == '\\';
  }
  
  // Returns true if the path starts with a drive specifier (e.g. "c:\").
  template <typename char_type>
  bool is_path_absolute(const char_type* path) {
    return has_drive_letter(path) && is_separator(path[2]);
  }
  
  template <typename char_type>
  bool is_drive_relative(const char_type* path) {
    return has_drive_letter(path) && (path[2] == 0 || !is_separator(path[2]));
  }
  
  wstring join_paths(const wstring& path1, const wstring& path2) {
    if (path1.empty() || is_path_absolute(path2.c_str()) ||
        has_longpath_prefix(path2.c_str())) {
      return path2;
    }
    if (path2.empty()) {
      return path1;
    }
  
    if (is_separator(path1[path1.size() - 1])) {
      return is_separator(path2[0]) ? (path1 + path2.substr(1))
                                         : (path1 + path2);
    } else {
      return is_separator(path2[0]) ? (path1 + path2)
                                         : (path1 + L'\\' + path2);
    }
  }
  
  wstring normalize(wstring path) {
    if (has_longpath_prefix(path.c_str())) {
      path = path.substr(4);
    }
  
    static const wstring dot(L".");
    static const wstring dotdot(L"..");
    const WCHAR* p = path.c_str();
  
    std::vector<wstring> segments;
    int segment_start = -1;
    // Find the path segments in `path` (separated by "/").
    for (int i = 0;; ++i) {
      if (!is_separator(p[i]) && p[i] != L'\0') {
        // The current character does not end a segment, so start one unless it's
        // already started.
        if (segment_start < 0) {
          segment_start = i;
        }
      } else if (segment_start >= 0 && i > segment_start) {
        // The current character is "/" or "\0", so this ends a segment.
        // Add that to `segments` if there's anything to add; handle "." and "..".
        wstring segment(p, segment_start, i - segment_start);
        segment_start = -1;
        if (segment == dotdot) {
          if (!segments.empty() &&
              (!has_drive_letter(segments[0].c_str()) || segments.size() > 1)) {
            segments.pop_back();
          }
        } else if (segment != dot && !segment.empty()) {
          segments.push_back(segment);
        }
      }
      if (p[i] == L'\0') {
        break;
      }
    }
  
    // Handle the case when `path` is just a drive specifier (or some degenerate
    // form of it, e.g. "c:\..").
    if (segments.size() == 1 && segments[0].size() == 2 &&
        has_drive_letter(segments[0].c_str())) {
      return segments[0] + L'\\';
    }
  
    // Join all segments.
    bool first = true;
    std::wstringstream result;
    for (int i = 0; i < segments.size(); ++i) {
      if (!first) {
        result << L'\\';
      }
      first = false;
      result << segments[i];
    }
    // Preserve trailing separator if the input contained it.
    if (!path.empty() && is_separator(p[path.size() - 1])) {
      result << L'\\';
    }
    return result.str();
  }
  
  bool as_windows_path(const char* path, wstring* result) {
    if (null_or_empty(path)) {
      result->clear();
      return true;
    }
    wstring wpath;
    if (!strings::utf8_to_wcs(path, &wpath)) {
      return false;
    }
    if (has_longpath_prefix(wpath.c_str())) {
      *result = wpath;
      return true;
    }
    if (is_separator(path[0]) || is_drive_relative(path)) {
      return false;
    }
  
  
    if (!is_path_absolute(wpath.c_str())) {
      int size = ::GetCurrentDirectoryW(0, nullptr);
      if (size == 0 && GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
        return false;
      }
      std::unique_ptr<WCHAR[]> wcwd(new WCHAR[size]);
      ::GetCurrentDirectoryW(size, wcwd.get());
      wpath = join_paths(wcwd.get(), wpath);
    }
    wpath = normalize(wpath);
    if (!has_longpath_prefix(wpath.c_str())) {
      // Add the "\\?\" prefix unconditionally. This way we prevent the Win32 API
      // from processing the path and "helpfully" removing trailing dots from the
      // path, for example.
      // See https://github.com/bazelbuild/bazel/issues/2935
      wpath = wstring(L"\\\\?\\") + wpath;
    }
    *result = wpath;
    return true;
  }
  
  }  // namespace
  
  int open(const char* path, int flags, int mode) {
  #ifdef SUPPORT_LONGPATHS
    wstring wpath;
    if (!as_windows_path(path, &wpath)) {
      errno = ENOENT;
      return -1;
    }
    return ::_wopen(wpath.c_str(), flags, mode);
  #else
    return ::_open(path, flags, mode);
  #endif
  }
  
  int mkdir(const char* path, int _mode) {
  #ifdef SUPPORT_LONGPATHS
    wstring wpath;
    if (!as_windows_path(path, &wpath)) {
      errno = ENOENT;
      return -1;
    }
    return ::_wmkdir(wpath.c_str());
  #else   // not SUPPORT_LONGPATHS
    return ::_mkdir(path);
  #endif  // not SUPPORT_LONGPATHS
  }
  
  int access(const char* path, int mode) {
  #ifdef SUPPORT_LONGPATHS
    wstring wpath;
    if (!as_windows_path(path, &wpath)) {
      errno = ENOENT;
      return -1;
    }
    return ::_waccess(wpath.c_str(), mode);
  #else
    return ::_access(path, mode);
  #endif
  }
  
  int chdir(const char* path) {
  #ifdef SUPPORT_LONGPATHS
    wstring wpath;
    if (!as_windows_path(path, &wpath)) {
      errno = ENOENT;
      return -1;
    }
    return ::_wchdir(wpath.c_str());
  #else
    return ::_chdir(path);
  #endif
  }
  
  int stat(const char* path, struct _stat* buffer) {
  #ifdef SUPPORT_LONGPATHS
    wstring wpath;
    if (!as_windows_path(path, &wpath)) {
      errno = ENOENT;
      return -1;
    }
    return ::_wstat(wpath.c_str(), buffer);
  #else   // not SUPPORT_LONGPATHS
    return ::_stat(path, buffer);
  #endif  // not SUPPORT_LONGPATHS
  }
  
  FILE* fopen(const char* path, const char* mode) {
  #ifdef SUPPORT_LONGPATHS
    if (null_or_empty(path)) {
      errno = EINVAL;
      return nullptr;
    }
    wstring wpath;
    if (!as_windows_path(path, &wpath)) {
      errno = ENOENT;
      return nullptr;
    }
    wstring wmode;
    if (!strings::utf8_to_wcs(mode, &wmode)) {
      errno = EINVAL;
      return nullptr;
    }
    return ::_wfopen(wpath.c_str(), wmode.c_str());
  #else
    return ::fopen(path, mode);
  #endif
  }
  
  int close(int fd) { return ::_close(fd); }
  
  int dup(int fd) { return ::_dup(fd); }
  
  int dup2(int fd1, int fd2) { return ::_dup2(fd1, fd2); }
  
  int read(int fd, void* buffer, size_t size) {
    return ::_read(fd, buffer, size);
  }
  
  int setmode(int fd, int mode) { return ::_setmode(fd, mode); }
  
  int write(int fd, const void* buffer, size_t size) {
    return ::_write(fd, buffer, size);
  }
  
  wstring testonly_utf8_to_winpath(const char* path) {
    wstring wpath;
    return as_windows_path(path, &wpath) ? wpath : wstring();
  }
  
  ExpandWildcardsResult ExpandWildcards(
      const string& path, std::function<void(const string&)> consume) {
    if (path.find_first_of("*?") == string::npos) {
      // There are no wildcards in the path, we don't need to expand it.
      consume(path);
      return ExpandWildcardsResult::kSuccess;
    }
  
    wstring wpath;
    if (!as_windows_path(path.c_str(), &wpath)) {
      return ExpandWildcardsResult::kErrorInputPathConversion;
    }
  
    static const wstring kDot = L".";
    static const wstring kDotDot = L"..";
    WIN32_FIND_DATAW metadata;
    HANDLE handle = ::FindFirstFileW(wpath.c_str(), &metadata);
    if (handle == INVALID_HANDLE_VALUE) {
      // The pattern does not match any files (or directories).
      return ExpandWildcardsResult::kErrorNoMatchingFile;
    }
  
    string::size_type pos = path.find_last_of("\\/");
    string dirname;
    if (pos != string::npos) {
      dirname = path.substr(0, pos + 1);
    }
  
    ExpandWildcardsResult matched = ExpandWildcardsResult::kErrorNoMatchingFile;
    do {
      // Ignore ".", "..", and directories.
      if ((metadata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0 &&
          kDot != metadata.cFileName && kDotDot != metadata.cFileName) {
        matched = ExpandWildcardsResult::kSuccess;
        string filename;
        if (!strings::wcs_to_utf8(metadata.cFileName, &filename)) {
          return ExpandWildcardsResult::kErrorOutputPathConversion;
        }
  
        if (dirname.empty()) {
          consume(filename);
        } else {
          consume(dirname + filename);
        }
      }
    } while (::FindNextFileW(handle, &metadata));
    FindClose(handle);
    return matched;
  }
  
  namespace strings {
  
  bool wcs_to_mbs(const WCHAR* s, string* out, bool outUtf8) {
    if (null_or_empty(s)) {
      out->clear();
      return true;
    }
    BOOL usedDefaultChar = FALSE;
    SetLastError(0);
    int size = WideCharToMultiByte(
        outUtf8 ? CP_UTF8 : CP_ACP, 0, s, -1, nullptr, 0, nullptr,
        outUtf8 ? nullptr : &usedDefaultChar);
    if ((size == 0 && GetLastError() != ERROR_INSUFFICIENT_BUFFER)
        || usedDefaultChar) {
      return false;
    }
    std::unique_ptr<CHAR[]> astr(new CHAR[size]);
    WideCharToMultiByte(
        outUtf8 ? CP_UTF8 : CP_ACP, 0, s, -1, astr.get(), size, nullptr, nullptr);
    out->assign(astr.get());
    return true;
  }
  
  bool mbs_to_wcs(const char* s, wstring* out, bool inUtf8) {
    if (null_or_empty(s)) {
      out->clear();
      return true;
    }
  
    SetLastError(0);
    int size =
        MultiByteToWideChar(inUtf8 ? CP_UTF8 : CP_ACP, 0, s, -1, nullptr, 0);
    if (size == 0 && GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
      return false;
    }
    std::unique_ptr<WCHAR[]> wstr(new WCHAR[size]);
    MultiByteToWideChar(
        inUtf8 ? CP_UTF8 : CP_ACP, 0, s, -1, wstr.get(), size + 1);
    out->assign(wstr.get());
    return true;
  }
  
  bool utf8_to_wcs(const char* input, wstring* out) {
    return mbs_to_wcs(input, out, true);
  }
  
  bool wcs_to_utf8(const wchar_t* input, string* out) {
    return wcs_to_mbs(input, out, true);
  }
  
  }  // namespace strings
  }  // namespace win32
  }  // namespace io
  }  // namespace protobuf
  }  // namespace google
  
  #endif  // defined(_WIN32)
  