[dart:io] Adds Platform.ansiSupported

runtime/bin/platform_win.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/platform.h"
 
 #include <crtdbg.h>
@@ skipping 47 matching lines @@
     // See: https://msdn.microsoft.com/en-us/library/windows/desktop/ms680621(v=vs.85).aspx
     SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);
   }
 
   static void SaveAndConfigureConsole() {
     MutexLocker ml(platform_win_mutex_);
     ASSERT(saved_output_cp_ == -1);
     saved_output_cp_ = GetConsoleOutputCP();
     SetConsoleOutputCP(CP_UTF8);
 
+    ansi_supported_ = true;
     HANDLE out = GetStdHandle(STD_OUTPUT_HANDLE);
     if ((out != INVALID_HANDLE_VALUE) &&
         GetConsoleMode(out, &saved_console_out_mode_)) {
       const DWORD request =
           saved_console_out_mode_ | ENABLE_VIRTUAL_TERMINAL_PROCESSING;
-      SetConsoleMode(out, request);
+      ansi_supported_ = ansi_supported_ && SetConsoleMode(out, request);
+    } else {
+      ansi_supported_ = false;
     }
 
     HANDLE in = GetStdHandle(STD_INPUT_HANDLE);
     if ((in != INVALID_HANDLE_VALUE) &&
         GetConsoleMode(in, &saved_console_in_mode_)) {
       const DWORD request =
           saved_console_in_mode_ | ENABLE_VIRTUAL_TERMINAL_INPUT;
-      SetConsoleMode(in, request);
+      ansi_supported_ = ansi_supported_ && SetConsoleMode(in, request);
+    } else {
+      ansi_supported_ = false;
     }
   }
 
   static void RestoreConsole() {
     MutexLocker ml(platform_win_mutex_);
     if (saved_output_cp_ != -1) {
       SetConsoleOutputCP(saved_output_cp_);
       saved_output_cp_ = -1;
     }
     HANDLE out = GetStdHandle(STD_OUTPUT_HANDLE);
     if (out != INVALID_HANDLE_VALUE) {
       SetConsoleMode(out, saved_console_out_mode_);
       saved_console_out_mode_ = 0;
     }
     HANDLE in = GetStdHandle(STD_INPUT_HANDLE);
     if (in != INVALID_HANDLE_VALUE) {
       SetConsoleMode(in, saved_console_in_mode_);
       saved_console_in_mode_ = 0;
     }
   }
 
+  static bool ansi_supported() { return ansi_supported_; }
+
  private:
   static Mutex* platform_win_mutex_;
   static int saved_output_cp_;
   static DWORD saved_console_out_mode_;
   static DWORD saved_console_in_mode_;
+  static bool ansi_supported_;
 
   static void InvalidParameterHandler(const wchar_t* expression,
                                       const wchar_t* function,
                                       const wchar_t* file,
                                       unsigned int line,
                                       uintptr_t reserved) {
     // Doing nothing here means that the CRT call that invoked it will
     // return an error code and/or set errno.
   }
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(PlatformWin);
 };
 
 int PlatformWin::saved_output_cp_ = -1;
 DWORD PlatformWin::saved_console_out_mode_ = 0;
 DWORD PlatformWin::saved_console_in_mode_ = 0;
 Mutex* PlatformWin::platform_win_mutex_ = NULL;
+bool PlatformWin::ansi_supported_ = false;
 
 bool Platform::Initialize() {
   PlatformWin::InitOnce();
   PlatformWin::SaveAndConfigureConsole();
   return true;
 }
 
 
 int Platform::NumberOfProcessors() {
   SYSTEM_INFO info;
@@ skipping 76 matching lines @@
   if (GetLastError() != ERROR_SUCCESS) {
     return NULL;
   }
   char* path = StringUtilsWin::WideToUtf8(tmp_buffer);
   // Return the canonical path as the returned path might contain symlinks.
   const char* canon_path = File::GetCanonicalPath(path);
   return canon_path;
 }
 
 
+bool Platform::AnsiSupported() {
+  return PlatformWin::ansi_supported();
+}
+
+
 void Platform::Exit(int exit_code) {
   // TODO(zra): Remove once VM shuts down cleanly.
   ::dart::private_flag_windows_run_tls_destructors = false;
   // Restore the console's output code page
   PlatformWin::RestoreConsole();
   // On Windows we use ExitProcess so that threads can't clobber the exit_code.
   // See: https://code.google.com/p/nativeclient/issues/detail?id=2870
   ::ExitProcess(exit_code);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)