lldb/source/Core/IOHandler.cpp

   1 //===-- IOHandler.cpp -----------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Core/IOHandler.h"
  10
  11 #if defined(__APPLE__)
  12 #include <deque>
  13 #endif
  14 #include <string>
  15
  16 #include "lldb/Core/Debugger.h"
  17 #include "lldb/Host/Config.h"
  18 #include "lldb/Host/File.h"
  19 #include "lldb/Host/StreamFile.h"
  20 #include "lldb/Utility/AnsiTerminal.h"
  21 #include "lldb/Utility/Predicate.h"
  22 #include "lldb/Utility/Status.h"
  23 #include "lldb/Utility/StreamString.h"
  24 #include "lldb/Utility/StringList.h"
  25 #include "lldb/lldb-forward.h"
  26
  27 #if LLDB_ENABLE_LIBEDIT
  28 #include "lldb/Host/Editline.h"
  29 #endif
  30 #include "lldb/Interpreter/CommandCompletions.h"
  31 #include "lldb/Interpreter/CommandInterpreter.h"
  32 #include "llvm/ADT/StringRef.h"
  33
  34 #ifdef _WIN32
  35 #include "lldb/Host/windows/windows.h"
  36 #endif
  37
  38 #include <memory>
  39 #include <mutex>
  40 #include <optional>
  41
  42 #include <cassert>
  43 #include <cctype>
  44 #include <cerrno>
  45 #include <clocale>
  46 #include <cstdint>
  47 #include <cstdio>
  48 #include <cstring>
  49 #include <type_traits>
  50
  51 using namespace lldb;
  52 using namespace lldb_private;
  53 using llvm::StringRef;
  54
  55 IOHandler::IOHandler(Debugger &debugger, IOHandler::Type type)
  56     : IOHandler(debugger, type,
  57                 FileSP(),       // Adopt STDIN from top input reader
  58                 StreamFileSP(), // Adopt STDOUT from top input reader
  59                 StreamFileSP(), // Adopt STDERR from top input reader
  60                 0               // Flags
  61
  62       ) {}
  63
  64 IOHandler::IOHandler(Debugger &debugger, IOHandler::Type type,
  65                      const lldb::FileSP &input_sp,
  66                      const lldb::StreamFileSP &output_sp,
  67                      const lldb::StreamFileSP &error_sp, uint32_t flags)
  68     : m_debugger(debugger), m_input_sp(input_sp), m_output_sp(output_sp),
  69       m_error_sp(error_sp), m_popped(false), m_flags(flags), m_type(type),
  70       m_user_data(nullptr), m_done(false), m_active(false) {
  71   // If any files are not specified, then adopt them from the top input reader.
  72   if (!m_input_sp || !m_output_sp || !m_error_sp)
  73     debugger.AdoptTopIOHandlerFilesIfInvalid(m_input_sp, m_output_sp,
  74                                              m_error_sp);
  75 }
  76
  77 IOHandler::~IOHandler() = default;
  78
  79 int IOHandler::GetInputFD() {
  80   return (m_input_sp ? m_input_sp->GetDescriptor() : -1);
  81 }
  82
  83 int IOHandler::GetOutputFD() {
  84   return (m_output_sp ? m_output_sp->GetFile().GetDescriptor() : -1);
  85 }
  86
  87 int IOHandler::GetErrorFD() {
  88   return (m_error_sp ? m_error_sp->GetFile().GetDescriptor() : -1);
  89 }
  90
  91 FILE *IOHandler::GetInputFILE() {
  92   return (m_input_sp ? m_input_sp->GetStream() : nullptr);
  93 }
  94
  95 FILE *IOHandler::GetOutputFILE() {
  96   return (m_output_sp ? m_output_sp->GetFile().GetStream() : nullptr);
  97 }
  98
  99 FILE *IOHandler::GetErrorFILE() {
 100   return (m_error_sp ? m_error_sp->GetFile().GetStream() : nullptr);
 101 }
 102
 103 FileSP IOHandler::GetInputFileSP() { return m_input_sp; }
 104
 105 StreamFileSP IOHandler::GetOutputStreamFileSP() { return m_output_sp; }
 106
 107 StreamFileSP IOHandler::GetErrorStreamFileSP() { return m_error_sp; }
 108
 109 bool IOHandler::GetIsInteractive() {
 110   return GetInputFileSP() ? GetInputFileSP()->GetIsInteractive() : false;
 111 }
 112
 113 bool IOHandler::GetIsRealTerminal() {
 114   return GetInputFileSP() ? GetInputFileSP()->GetIsRealTerminal() : false;
 115 }
 116
 117 void IOHandler::SetPopped(bool b) { m_popped.SetValue(b, eBroadcastOnChange); }
 118
 119 void IOHandler::WaitForPop() { m_popped.WaitForValueEqualTo(true); }
 120
 121 void IOHandler::PrintAsync(const char *s, size_t len, bool is_stdout) {
 122   std::lock_guard<std::recursive_mutex> guard(m_output_mutex);
 123   lldb::StreamFileSP stream = is_stdout ? m_output_sp : m_error_sp;
 124   stream->Write(s, len);
 125   stream->Flush();
 126 }
 127
 128 bool IOHandlerStack::PrintAsync(const char *s, size_t len, bool is_stdout) {
 129   std::lock_guard<std::recursive_mutex> guard(m_mutex);
 130   if (!m_top)
 131     return false;
 132   m_top->PrintAsync(s, len, is_stdout);
 133   return true;
 134 }
 135
 136 IOHandlerConfirm::IOHandlerConfirm(Debugger &debugger, llvm::StringRef prompt,
 137                                    bool default_response)
 138     : IOHandlerEditline(
 139           debugger, IOHandler::Type::Confirm,
 140           nullptr, // nullptr editline_name means no history loaded/saved
 141           llvm::StringRef(), // No prompt
 142           llvm::StringRef(), // No continuation prompt
 143           false,             // Multi-line
 144           false, // Don't colorize the prompt (i.e. the confirm message.)
 145           0, *this),
 146       m_default_response(default_response), m_user_response(default_response) {
 147   StreamString prompt_stream;
 148   prompt_stream.PutCString(prompt);
 149   if (m_default_response)
 150     prompt_stream.Printf(": [Y/n] ");
 151   else
 152     prompt_stream.Printf(": [y/N] ");
 153
 154   SetPrompt(prompt_stream.GetString());
 155 }
 156
 157 IOHandlerConfirm::~IOHandlerConfirm() = default;
 158
 159 void IOHandlerConfirm::IOHandlerComplete(IOHandler &io_handler,
 160                                          CompletionRequest &request) {
 161   if (request.GetRawCursorPos() != 0)
 162     return;
 163   request.AddCompletion(m_default_response ? "y" : "n");
 164 }
 165
 166 void IOHandlerConfirm::IOHandlerInputComplete(IOHandler &io_handler,
 167                                               std::string &line) {
 168   if (line.empty()) {
 169     // User just hit enter, set the response to the default
 170     m_user_response = m_default_response;
 171     io_handler.SetIsDone(true);
 172     return;
 173   }
 174
 175   if (line.size() == 1) {
 176     switch (line[0]) {
 177     case 'y':
 178     case 'Y':
 179       m_user_response = true;
 180       io_handler.SetIsDone(true);
 181       return;
 182     case 'n':
 183     case 'N':
 184       m_user_response = false;
 185       io_handler.SetIsDone(true);
 186       return;
 187     default:
 188       break;
 189     }
 190   }
 191
 192   if (line == "yes" || line == "YES" || line == "Yes") {
 193     m_user_response = true;
 194     io_handler.SetIsDone(true);
 195   } else if (line == "no" || line == "NO" || line == "No") {
 196     m_user_response = false;
 197     io_handler.SetIsDone(true);
 198   }
 199 }
 200
 201 std::optional<std::string>
 202 IOHandlerDelegate::IOHandlerSuggestion(IOHandler &io_handler,
 203                                        llvm::StringRef line) {
 204   return io_handler.GetDebugger()
 205       .GetCommandInterpreter()
 206       .GetAutoSuggestionForCommand(line);
 207 }
 208
 209 void IOHandlerDelegate::IOHandlerComplete(IOHandler &io_handler,
 210                                           CompletionRequest &request) {
 211   switch (m_completion) {
 212   case Completion::None:
 213     break;
 214   case Completion::LLDBCommand:
 215     io_handler.GetDebugger().GetCommandInterpreter().HandleCompletion(request);
 216     break;
 217   case Completion::Expression:
 218     lldb_private::CommandCompletions::InvokeCommonCompletionCallbacks(
 219         io_handler.GetDebugger().GetCommandInterpreter(),
 220         lldb::eVariablePathCompletion, request, nullptr);
 221     break;
 222   }
 223 }
 224
 225 IOHandlerEditline::IOHandlerEditline(
 226     Debugger &debugger, IOHandler::Type type,
 227     const char *editline_name, // Used for saving history files
 228     llvm::StringRef prompt, llvm::StringRef continuation_prompt,
 229     bool multi_line, bool color, uint32_t line_number_start,
 230     IOHandlerDelegate &delegate)
 231     : IOHandlerEditline(debugger, type,
 232                         FileSP(),       // Inherit input from top input reader
 233                         StreamFileSP(), // Inherit output from top input reader
 234                         StreamFileSP(), // Inherit error from top input reader
 235                         0,              // Flags
 236                         editline_name,  // Used for saving history files
 237                         prompt, continuation_prompt, multi_line, color,
 238                         line_number_start, delegate) {}
 239
 240 IOHandlerEditline::IOHandlerEditline(
 241     Debugger &debugger, IOHandler::Type type, const lldb::FileSP &input_sp,
 242     const lldb::StreamFileSP &output_sp, const lldb::StreamFileSP &error_sp,
 243     uint32_t flags,
 244     const char *editline_name, // Used for saving history files
 245     llvm::StringRef prompt, llvm::StringRef continuation_prompt,
 246     bool multi_line, bool color, uint32_t line_number_start,
 247     IOHandlerDelegate &delegate)
 248     : IOHandler(debugger, type, input_sp, output_sp, error_sp, flags),
 249 #if LLDB_ENABLE_LIBEDIT
 250       m_editline_up(),
 251 #endif
 252       m_delegate(delegate), m_prompt(), m_continuation_prompt(),
 253       m_current_lines_ptr(nullptr), m_base_line_number(line_number_start),
 254       m_curr_line_idx(UINT32_MAX), m_multi_line(multi_line), m_color(color),
 255       m_interrupt_exits(true) {
 256   SetPrompt(prompt);
 257
 258 #if LLDB_ENABLE_LIBEDIT
 259   bool use_editline = false;
 260
 261   use_editline = GetInputFILE() && GetOutputFILE() && GetErrorFILE() &&
 262                  m_input_sp && m_input_sp->GetIsRealTerminal();
 263
 264   if (use_editline) {
 265     m_editline_up = std::make_unique<Editline>(editline_name, GetInputFILE(),
 266                                                GetOutputFILE(), GetErrorFILE(),
 267                                                m_color, GetOutputMutex());
 268     m_editline_up->SetIsInputCompleteCallback(
 269         [this](Editline *editline, StringList &lines) {
 270           return this->IsInputCompleteCallback(editline, lines);
 271         });
 272
 273     m_editline_up->SetAutoCompleteCallback([this](CompletionRequest &request) {
 274       this->AutoCompleteCallback(request);
 275     });
 276
 277     if (debugger.GetUseAutosuggestion()) {
 278       m_editline_up->SetSuggestionCallback([this](llvm::StringRef line) {
 279         return this->SuggestionCallback(line);
 280       });
 281       m_editline_up->SetSuggestionAnsiPrefix(ansi::FormatAnsiTerminalCodes(
 282           debugger.GetAutosuggestionAnsiPrefix()));
 283       m_editline_up->SetSuggestionAnsiSuffix(ansi::FormatAnsiTerminalCodes(
 284           debugger.GetAutosuggestionAnsiSuffix()));
 285     }
 286     // See if the delegate supports fixing indentation
 287     const char *indent_chars = delegate.IOHandlerGetFixIndentationCharacters();
 288     if (indent_chars) {
 289       // The delegate does support indentation, hook it up so when any
 290       // indentation character is typed, the delegate gets a chance to fix it
 291       FixIndentationCallbackType f = [this](Editline *editline,
 292                                             const StringList &lines,
 293                                             int cursor_position) {
 294         return this->FixIndentationCallback(editline, lines, cursor_position);
 295       };
 296       m_editline_up->SetFixIndentationCallback(std::move(f), indent_chars);
 297     }
 298   }
 299 #endif
 300   SetBaseLineNumber(m_base_line_number);
 301   SetPrompt(prompt);
 302   SetContinuationPrompt(continuation_prompt);
 303 }
 304
 305 IOHandlerEditline::~IOHandlerEditline() {
 306 #if LLDB_ENABLE_LIBEDIT
 307   m_editline_up.reset();
 308 #endif
 309 }
 310
 311 void IOHandlerEditline::Activate() {
 312   IOHandler::Activate();
 313   m_delegate.IOHandlerActivated(*this, GetIsInteractive());
 314 }
 315
 316 void IOHandlerEditline::Deactivate() {
 317   IOHandler::Deactivate();
 318   m_delegate.IOHandlerDeactivated(*this);
 319 }
 320
 321 void IOHandlerEditline::TerminalSizeChanged() {
 322 #if LLDB_ENABLE_LIBEDIT
 323   if (m_editline_up)
 324     m_editline_up->TerminalSizeChanged();
 325 #endif
 326 }
 327
 328 // Split out a line from the buffer, if there is a full one to get.
 329 static std::optional<std::string> SplitLine(std::string &line_buffer) {
 330   size_t pos = line_buffer.find('\n');
 331   if (pos == std::string::npos)
 332     return std::nullopt;
 333   std::string line =
 334       std::string(StringRef(line_buffer.c_str(), pos).rtrim("\n\r"));
 335   line_buffer = line_buffer.substr(pos + 1);
 336   return line;
 337 }
 338
 339 // If the final line of the file ends without a end-of-line, return
 340 // it as a line anyway.
 341 static std::optional<std::string> SplitLineEOF(std::string &line_buffer) {
 342   if (llvm::all_of(line_buffer, llvm::isSpace))
 343     return std::nullopt;
 344   std::string line = std::move(line_buffer);
 345   line_buffer.clear();
 346   return line;
 347 }
 348
 349 bool IOHandlerEditline::GetLine(std::string &line, bool &interrupted) {
 350 #if LLDB_ENABLE_LIBEDIT
 351   if (m_editline_up) {
 352     return m_editline_up->GetLine(line, interrupted);
 353   }
 354 #endif
 355
 356   line.clear();
 357
 358   if (GetIsInteractive()) {
 359     const char *prompt = nullptr;
 360
 361     if (m_multi_line && m_curr_line_idx > 0)
 362       prompt = GetContinuationPrompt();
 363
 364     if (prompt == nullptr)
 365       prompt = GetPrompt();
 366
 367     if (prompt && prompt[0]) {
 368       if (m_output_sp) {
 369         m_output_sp->Printf("%s", prompt);
 370         m_output_sp->Flush();
 371       }
 372     }
 373   }
 374
 375   std::optional<std::string> got_line = SplitLine(m_line_buffer);
 376
 377   if (!got_line && !m_input_sp) {
 378     // No more input file, we are done...
 379     SetIsDone(true);
 380     return false;
 381   }
 382
 383   FILE *in = GetInputFILE();
 384   char buffer[256];
 385
 386   if (!got_line && !in && m_input_sp) {
 387     // there is no FILE*, fall back on just reading bytes from the stream.
 388     while (!got_line) {
 389       size_t bytes_read = sizeof(buffer);
 390       Status error = m_input_sp->Read((void *)buffer, bytes_read);
 391       if (error.Success() && !bytes_read) {
 392         got_line = SplitLineEOF(m_line_buffer);
 393         break;
 394       }
 395       if (error.Fail())
 396         break;
 397       m_line_buffer += StringRef(buffer, bytes_read);
 398       got_line = SplitLine(m_line_buffer);
 399     }
 400   }
 401
 402   if (!got_line && in) {
 403     while (!got_line) {
 404       char *r = fgets(buffer, sizeof(buffer), in);
 405 #ifdef _WIN32
 406       // ReadFile on Windows is supposed to set ERROR_OPERATION_ABORTED
 407       // according to the docs on MSDN. However, this has evidently been a
 408       // known bug since Windows 8. Therefore, we can't detect if a signal
 409       // interrupted in the fgets. So pressing ctrl-c causes the repl to end
 410       // and the process to exit. A temporary workaround is just to attempt to
 411       // fgets twice until this bug is fixed.
 412       if (r == nullptr)
 413         r = fgets(buffer, sizeof(buffer), in);
 414       // this is the equivalent of EINTR for Windows
 415       if (r == nullptr && GetLastError() == ERROR_OPERATION_ABORTED)
 416         continue;
 417 #endif
 418       if (r == nullptr) {
 419         if (ferror(in) && errno == EINTR)
 420           continue;
 421         if (feof(in))
 422           got_line = SplitLineEOF(m_line_buffer);
 423         break;
 424       }
 425       m_line_buffer += buffer;
 426       got_line = SplitLine(m_line_buffer);
 427     }
 428   }
 429
 430   if (got_line) {
 431     line = *got_line;
 432   }
 433
 434   return (bool)got_line;
 435 }
 436
 437 #if LLDB_ENABLE_LIBEDIT
 438 bool IOHandlerEditline::IsInputCompleteCallback(Editline *editline,
 439                                                 StringList &lines) {
 440   return m_delegate.IOHandlerIsInputComplete(*this, lines);
 441 }
 442
 443 int IOHandlerEditline::FixIndentationCallback(Editline *editline,
 444                                               const StringList &lines,
 445                                               int cursor_position) {
 446   return m_delegate.IOHandlerFixIndentation(*this, lines, cursor_position);
 447 }
 448
 449 std::optional<std::string>
 450 IOHandlerEditline::SuggestionCallback(llvm::StringRef line) {
 451   return m_delegate.IOHandlerSuggestion(*this, line);
 452 }
 453
 454 void IOHandlerEditline::AutoCompleteCallback(CompletionRequest &request) {
 455   m_delegate.IOHandlerComplete(*this, request);
 456 }
 457 #endif
 458
 459 const char *IOHandlerEditline::GetPrompt() {
 460 #if LLDB_ENABLE_LIBEDIT
 461   if (m_editline_up) {
 462     return m_editline_up->GetPrompt();
 463   } else {
 464 #endif
 465     if (m_prompt.empty())
 466       return nullptr;
 467 #if LLDB_ENABLE_LIBEDIT
 468   }
 469 #endif
 470   return m_prompt.c_str();
 471 }
 472
 473 bool IOHandlerEditline::SetPrompt(llvm::StringRef prompt) {
 474   m_prompt = std::string(prompt);
 475
 476 #if LLDB_ENABLE_LIBEDIT
 477   if (m_editline_up) {
 478     m_editline_up->SetPrompt(m_prompt.empty() ? nullptr : m_prompt.c_str());
 479     m_editline_up->SetPromptAnsiPrefix(
 480         ansi::FormatAnsiTerminalCodes(m_debugger.GetPromptAnsiPrefix()));
 481     m_editline_up->SetPromptAnsiSuffix(
 482         ansi::FormatAnsiTerminalCodes(m_debugger.GetPromptAnsiSuffix()));
 483   }
 484 #endif
 485   return true;
 486 }
 487
 488 const char *IOHandlerEditline::GetContinuationPrompt() {
 489   return (m_continuation_prompt.empty() ? nullptr
 490                                         : m_continuation_prompt.c_str());
 491 }
 492
 493 void IOHandlerEditline::SetContinuationPrompt(llvm::StringRef prompt) {
 494   m_continuation_prompt = std::string(prompt);
 495
 496 #if LLDB_ENABLE_LIBEDIT
 497   if (m_editline_up)
 498     m_editline_up->SetContinuationPrompt(m_continuation_prompt.empty()
 499                                              ? nullptr
 500                                              : m_continuation_prompt.c_str());
 501 #endif
 502 }
 503
 504 void IOHandlerEditline::SetBaseLineNumber(uint32_t line) {
 505   m_base_line_number = line;
 506 }
 507
 508 uint32_t IOHandlerEditline::GetCurrentLineIndex() const {
 509 #if LLDB_ENABLE_LIBEDIT
 510   if (m_editline_up)
 511     return m_editline_up->GetCurrentLine();
 512 #endif
 513   return m_curr_line_idx;
 514 }
 515
 516 StringList IOHandlerEditline::GetCurrentLines() const {
 517 #if LLDB_ENABLE_LIBEDIT
 518   if (m_editline_up)
 519     return m_editline_up->GetInputAsStringList();
 520 #endif
 521   // When libedit is not used, the current lines can be gotten from
 522   // `m_current_lines_ptr`, which is updated whenever a new line is processed.
 523   // This doesn't happen when libedit is used, in which case
 524   // `m_current_lines_ptr` is only updated when the full input is terminated.
 525
 526   if (m_current_lines_ptr)
 527     return *m_current_lines_ptr;
 528   return StringList();
 529 }
 530
 531 bool IOHandlerEditline::GetLines(StringList &lines, bool &interrupted) {
 532   m_current_lines_ptr = &lines;
 533
 534   bool success = false;
 535 #if LLDB_ENABLE_LIBEDIT
 536   if (m_editline_up) {
 537     return m_editline_up->GetLines(m_base_line_number, lines, interrupted);
 538   } else {
 539 #endif
 540     bool done = false;
 541     Status error;
 542
 543     while (!done) {
 544       // Show line numbers if we are asked to
 545       std::string line;
 546       if (m_base_line_number > 0 && GetIsInteractive()) {
 547         if (m_output_sp) {
 548           m_output_sp->Printf("%u%s",
 549                               m_base_line_number + (uint32_t)lines.GetSize(),
 550                               GetPrompt() == nullptr ? " " : "");
 551         }
 552       }
 553
 554       m_curr_line_idx = lines.GetSize();
 555
 556       bool interrupted = false;
 557       if (GetLine(line, interrupted) && !interrupted) {
 558         lines.AppendString(line);
 559         done = m_delegate.IOHandlerIsInputComplete(*this, lines);
 560       } else {
 561         done = true;
 562       }
 563     }
 564     success = lines.GetSize() > 0;
 565 #if LLDB_ENABLE_LIBEDIT
 566   }
 567 #endif
 568   return success;
 569 }
 570
 571 // Each IOHandler gets to run until it is done. It should read data from the
 572 // "in" and place output into "out" and "err and return when done.
 573 void IOHandlerEditline::Run() {
 574   std::string line;
 575   while (IsActive()) {
 576     bool interrupted = false;
 577     if (m_multi_line) {
 578       StringList lines;
 579       if (GetLines(lines, interrupted)) {
 580         if (interrupted) {
 581           m_done = m_interrupt_exits;
 582           m_delegate.IOHandlerInputInterrupted(*this, line);
 583
 584         } else {
 585           line = lines.CopyList();
 586           m_delegate.IOHandlerInputComplete(*this, line);
 587         }
 588       } else {
 589         m_done = true;
 590       }
 591     } else {
 592       if (GetLine(line, interrupted)) {
 593         if (interrupted)
 594           m_delegate.IOHandlerInputInterrupted(*this, line);
 595         else
 596           m_delegate.IOHandlerInputComplete(*this, line);
 597       } else {
 598         m_done = true;
 599       }
 600     }
 601   }
 602 }
 603
 604 void IOHandlerEditline::Cancel() {
 605 #if LLDB_ENABLE_LIBEDIT
 606   if (m_editline_up)
 607     m_editline_up->Cancel();
 608 #endif
 609 }
 610
 611 bool IOHandlerEditline::Interrupt() {
 612   // Let the delgate handle it first
 613   if (m_delegate.IOHandlerInterrupt(*this))
 614     return true;
 615
 616 #if LLDB_ENABLE_LIBEDIT
 617   if (m_editline_up)
 618     return m_editline_up->Interrupt();
 619 #endif
 620   return false;
 621 }
 622
 623 void IOHandlerEditline::GotEOF() {
 624 #if LLDB_ENABLE_LIBEDIT
 625   if (m_editline_up)
 626     m_editline_up->Interrupt();
 627 #endif
 628 }
 629
 630 void IOHandlerEditline::PrintAsync(const char *s, size_t len, bool is_stdout) {
 631 #if LLDB_ENABLE_LIBEDIT
 632   if (m_editline_up) {
 633     std::lock_guard<std::recursive_mutex> guard(m_output_mutex);
 634     lldb::StreamFileSP stream = is_stdout ? m_output_sp : m_error_sp;
 635     m_editline_up->PrintAsync(stream.get(), s, len);
 636   } else
 637 #endif
 638   {
 639 #ifdef _WIN32
 640     const char *prompt = GetPrompt();
 641     if (prompt) {
 642       // Back up over previous prompt using Windows API
 643       CONSOLE_SCREEN_BUFFER_INFO screen_buffer_info;
 644       HANDLE console_handle = GetStdHandle(STD_OUTPUT_HANDLE);
 645       GetConsoleScreenBufferInfo(console_handle, &screen_buffer_info);
 646       COORD coord = screen_buffer_info.dwCursorPosition;
 647       coord.X -= strlen(prompt);
 648       if (coord.X < 0)
 649         coord.X = 0;
 650       SetConsoleCursorPosition(console_handle, coord);
 651     }
 652 #endif
 653     IOHandler::PrintAsync(s, len, is_stdout);
 654 #ifdef _WIN32
 655     if (prompt)
 656       IOHandler::PrintAsync(prompt, strlen(prompt), is_stdout);
 657 #endif
 658   }
 659 }