widget/windows/WindowsConsole.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "WindowsConsole.h"
   7
   8 #include <windows.h>
   9 #include <fcntl.h>
  10
  11 namespace mozilla {
  12
  13 static void AssignStdHandle(const char* aPath, const char* aMode, FILE* aStream,
  14                             DWORD aStdHandle) {
  15   // Visual Studio's _fileno() returns -2 for the standard
  16   // streams if they aren't associated with an output stream.
  17   const int fd = _fileno(aStream);
  18   if (fd == -2) {
  19     freopen(aPath, aMode, aStream);
  20     return;
  21   }
  22   if (fd < 0) {
  23     return;
  24   }
  25
  26   const HANDLE handle = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
  27   if (handle == INVALID_HANDLE_VALUE) {
  28     return;
  29   }
  30
  31   const HANDLE oldHandle = GetStdHandle(aStdHandle);
  32   if (handle == oldHandle) {
  33     return;
  34   }
  35
  36   SetStdHandle(aStdHandle, handle);
  37 }
  38
  39 // This code attaches the process to the appropriate console.
  40 void UseParentConsole() {
  41   if (AttachConsole(ATTACH_PARENT_PROCESS)) {
  42     // Redirect the standard streams to the existing console, but
  43     // only if they haven't been redirected to a valid file.
  44     AssignStdHandle("CONOUT$", "w", stdout, STD_OUTPUT_HANDLE);
  45     // There is no CONERR$, so use CONOUT$ for stderr as well.
  46     AssignStdHandle("CONOUT$", "w", stderr, STD_ERROR_HANDLE);
  47     AssignStdHandle("CONIN$", "r", stdin, STD_INPUT_HANDLE);
  48   }
  49 }
  50
  51 }  // namespace mozilla