+/// Returns the environment variable \arg Name's value as a string encoded in
+/// UTF-8. \arg Name is assumed to be in UTF-8 encoding.
+Optional<std::string> Process::GetEnv(StringRef Name) {
+ // Convert the argument to UTF-16 to pass it to _wgetenv().
+ SmallVector<wchar_t, 128> NameUTF16;
+ if (windows::UTF8ToUTF16(Name, NameUTF16))
+ return None;
+
+ // Environment variable can be encoded in non-UTF8 encoding, and there's no
+ // way to know what the encoding is. The only reliable way to look up
+ // multibyte environment variable is to use GetEnvironmentVariableW().
+ SmallVector<wchar_t, MAX_PATH> Buf;
+ size_t Size = MAX_PATH;
+ do {
+ Buf.reserve(Size);
+ Size =
+ GetEnvironmentVariableW(NameUTF16.data(), Buf.data(), Buf.capacity());
+ if (Size == 0)
+ return None;
+
+ // Try again with larger buffer.
+ } while (Size > Buf.capacity());
+ Buf.set_size(Size);
+
+ // Convert the result from UTF-16 to UTF-8.
+ SmallVector<char, MAX_PATH> Res;
+ if (windows::UTF16ToUTF8(Buf.data(), Size, Res))
+ return None;
+ return std::string(Res.data());
+}
+
+static std::error_code windows_error(DWORD E) {
+ return mapWindowsError(E);
+}
+
+static void AllocateAndPush(const SmallVectorImpl<char> &S,
+ SmallVectorImpl<const char *> &Vector,
+ SpecificBumpPtrAllocator<char> &Allocator) {
+ char *Buffer = Allocator.Allocate(S.size() + 1);
+ ::memcpy(Buffer, S.data(), S.size());
+ Buffer[S.size()] = '\0';
+ Vector.push_back(Buffer);
+}
+
+/// Convert Arg from UTF-16 to UTF-8 and push it onto Args.
+static std::error_code
+ConvertAndPushArg(const wchar_t *Arg, SmallVectorImpl<const char *> &Args,
+ SpecificBumpPtrAllocator<char> &Allocator) {
+ SmallVector<char, MAX_PATH> ArgString;
+ if (std::error_code ec = windows::UTF16ToUTF8(Arg, wcslen(Arg), ArgString))
+ return ec;
+ AllocateAndPush(ArgString, Args, Allocator);
+ return std::error_code();
+}
+
+/// \brief Perform wildcard expansion of Arg, or just push it into Args if it
+/// doesn't have wildcards or doesn't match any files.
+static std::error_code
+WildcardExpand(const wchar_t *Arg, SmallVectorImpl<const char *> &Args,
+ SpecificBumpPtrAllocator<char> &Allocator) {
+ if (!wcspbrk(Arg, L"*?")) {
+ // Arg does not contain any wildcard characters. This is the common case.
+ return ConvertAndPushArg(Arg, Args, Allocator);
+ }
+
+ if (wcscmp(Arg, L"/?") == 0 || wcscmp(Arg, L"-?") == 0) {
+ // Don't wildcard expand /?. Always treat it as an option.
+ return ConvertAndPushArg(Arg, Args, Allocator);
+ }
+
+ // Extract any directory part of the argument.
+ SmallVector<char, MAX_PATH> Dir;
+ if (std::error_code ec = windows::UTF16ToUTF8(Arg, wcslen(Arg), Dir))
+ return ec;
+ sys::path::remove_filename(Dir);
+ const int DirSize = Dir.size();
+
+ // Search for matching files.
+ WIN32_FIND_DATAW FileData;
+ HANDLE FindHandle = FindFirstFileW(Arg, &FileData);
+ if (FindHandle == INVALID_HANDLE_VALUE) {
+ return ConvertAndPushArg(Arg, Args, Allocator);
+ }
+
+ std::error_code ec;
+ do {
+ SmallVector<char, MAX_PATH> FileName;
+ ec = windows::UTF16ToUTF8(FileData.cFileName, wcslen(FileData.cFileName),
+ FileName);
+ if (ec)
+ break;
+
+ // Push the filename onto Dir, and remove it afterwards.
+ llvm::sys::path::append(Dir, StringRef(FileName.data(), FileName.size()));
+ AllocateAndPush(Dir, Args, Allocator);
+ Dir.resize(DirSize);
+ } while (FindNextFileW(FindHandle, &FileData));
+
+ FindClose(FindHandle);
+ return ec;
+}
+
+std::error_code
+Process::GetArgumentVector(SmallVectorImpl<const char *> &Args,
+ ArrayRef<const char *>,
+ SpecificBumpPtrAllocator<char> &ArgAllocator) {
+ int ArgCount;
+ wchar_t **UnicodeCommandLine =
+ CommandLineToArgvW(GetCommandLineW(), &ArgCount);
+ if (!UnicodeCommandLine)
+ return windows_error(::GetLastError());
+
+ Args.reserve(ArgCount);
+ std::error_code ec;
+
+ for (int i = 0; i < ArgCount; ++i) {
+ ec = WildcardExpand(UnicodeCommandLine[i], Args, ArgAllocator);
+ if (ec)
+ break;
+ }
+
+ LocalFree(UnicodeCommandLine);
+ return ec;
+}
+