lib/colorize-w32.c

   1 /* Output colorization on MS-Windows.
   2    Copyright 2011-2025 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Eli Zaretskii.  */
  18
  19 #include <config.h>
  20
  21 #include "colorize.h"
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27
  28 #undef DATADIR  /* conflicts with objidl.h, which is included by windows.h */
  29 #include <windows.h>
  30
  31 static HANDLE hstdout = INVALID_HANDLE_VALUE;
  32 static SHORT norm_attr;
  33
  34 /* Initialize the normal text attribute used by the console.  */
  35 void
  36 init_colorize (void)
  37 {
  38   CONSOLE_SCREEN_BUFFER_INFO csbi;
  39
  40   hstdout = GetStdHandle (STD_OUTPUT_HANDLE);
  41   if (hstdout != INVALID_HANDLE_VALUE
  42       && GetConsoleScreenBufferInfo (hstdout, &csbi))
  43      norm_attr = csbi.wAttributes;
  44   else
  45     hstdout = INVALID_HANDLE_VALUE;
  46 }
  47
  48 /* Return non-zero if we should highlight matches in output.  */
  49 int
  50 should_colorize (void)
  51 {
  52   /* $TERM is not normally defined on DOS/Windows, so don't require
  53      it for highlighting.  But some programs, like Emacs, do define
  54      it when running Grep as a subprocess, so make sure they don't
  55      set TERM=dumb.  */
  56   char const *t = getenv ("TERM");
  57   return ! (t && strcmp (t, "dumb") == 0);
  58 }
  59
  60 /* Convert a color spec, a semi-colon separated list of the form
  61    "NN;MM;KK;...", where each number is a value of the SGR parameter,
  62    into the corresponding Windows console text attribute.
  63
  64    This function supports a subset of the SGR rendition aspects that
  65    the Windows console can display.  */
  66 static int
  67 w32_sgr2attr (const char *sgr_seq)
  68 {
  69   const char *s, *p;
  70   int code, fg = norm_attr & 15, bg = norm_attr & (15 << 4);
  71   int bright = 0, inverse = 0;
  72   static const int fg_color[] = {
  73     0,                  /* black */
  74     FOREGROUND_RED,     /* red */
  75     FOREGROUND_GREEN,   /* green */
  76     FOREGROUND_GREEN | FOREGROUND_RED, /* yellow */
  77     FOREGROUND_BLUE,                   /* blue */
  78     FOREGROUND_BLUE | FOREGROUND_RED,  /* magenta */
  79     FOREGROUND_BLUE | FOREGROUND_GREEN, /* cyan */
  80     FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE /* gray */
  81   };
  82   static const int bg_color[] = {
  83     0,                  /* black */
  84     BACKGROUND_RED,     /* red */
  85     BACKGROUND_GREEN,   /* green */
  86     BACKGROUND_GREEN | BACKGROUND_RED, /* yellow */
  87     BACKGROUND_BLUE,                   /* blue */
  88     BACKGROUND_BLUE | BACKGROUND_RED,  /* magenta */
  89     BACKGROUND_BLUE | BACKGROUND_GREEN, /* cyan */
  90     BACKGROUND_RED | BACKGROUND_GREEN | BACKGROUND_BLUE /* gray */
  91   };
  92
  93   for (s = p = sgr_seq; *s; p++)
  94     {
  95       if (*p == ';' || *p == '\0')
  96         {
  97           code = strtol (s, nullptr, 10);
  98           s = p + (*p != '\0');
  99
 100           switch (code)
 101             {
 102             case 0:     /* all attributes off */
 103               fg = norm_attr & 15;
 104               bg = norm_attr & (15 << 4);
 105               bright = 0;
 106               inverse = 0;
 107               break;
 108             case 1:     /* intensity on */
 109               bright = 1;
 110               break;
 111             case 7:     /* inverse video */
 112               inverse = 1;
 113               break;
 114             case 22:    /* intensity off */
 115               bright = 0;
 116               break;
 117             case 27:    /* inverse off */
 118               inverse = 0;
 119               break;
 120             case 30: case 31: case 32: case 33: /* foreground color */
 121             case 34: case 35: case 36: case 37:
 122               fg = fg_color[code - 30];
 123               break;
 124             case 39:    /* default foreground */
 125               fg = norm_attr & 15;
 126               break;
 127             case 40: case 41: case 42: case 43: /* background color */
 128             case 44: case 45: case 46: case 47:
 129               bg = bg_color[code - 40];
 130               break;
 131             case 49:    /* default background */
 132               bg = norm_attr & (15 << 4);
 133               break;
 134             default:
 135               break;
 136             }
 137         }
 138     }
 139   if (inverse)
 140     {
 141       int t = fg;
 142       fg = (bg >> 4);
 143       bg = (t << 4);
 144     }
 145   if (bright)
 146     fg |= FOREGROUND_INTENSITY;
 147
 148   return (bg & (15 << 4)) | (fg & 15);
 149 }
 150
 151 /* Start a colorized text attribute on stdout using the SGR_START
 152    format; the attribute is specified by SGR_SEQ.  */
 153 void
 154 print_start_colorize (char const *sgr_start, char const *sgr_seq)
 155 {
 156   /* If stdout is connected to a console, set the console text
 157      attribute directly instead of using SGR_START.  Otherwise, use
 158      SGR_START to emit the SGR escape sequence as on Posix platforms;
 159      this is needed when Grep is invoked as a subprocess of another
 160      program, such as Emacs, which will handle the display of the
 161      matches.  */
 162   if (hstdout != INVALID_HANDLE_VALUE)
 163     {
 164       SHORT attr = w32_sgr2attr (sgr_seq);
 165       SetConsoleTextAttribute (hstdout, attr);
 166     }
 167   else
 168     printf (sgr_start, sgr_seq);
 169 }
 170
 171 /* Clear to the end of the current line with the default attribute.
 172    This is needed for reasons similar to those that require the "EL to
 173    Right after SGR" operation on Posix platforms: if we don't do this,
 174    setting the 'mt', 'ms', or 'mc' capabilities to use a non-default
 175    background color spills that color to the empty space at the end of
 176    the last screen line in a match whose line spans multiple screen
 177    lines.  */
 178 static void
 179 w32_clreol (void)
 180 {
 181   DWORD nchars;
 182   COORD start_pos;
 183   DWORD written;
 184   CONSOLE_SCREEN_BUFFER_INFO csbi;
 185
 186   GetConsoleScreenBufferInfo (hstdout, &csbi);
 187   start_pos = csbi.dwCursorPosition;
 188   nchars = csbi.dwSize.X - start_pos.X;
 189
 190   FillConsoleOutputAttribute (hstdout, norm_attr, nchars, start_pos,
 191                               &written);
 192   FillConsoleOutputCharacter (hstdout, ' ', nchars, start_pos, &written);
 193 }
 194
 195 /* Restore the normal text attribute using the SGR_END string.  */
 196 void
 197 print_end_colorize (char const *sgr_end)
 198 {
 199   if (hstdout != INVALID_HANDLE_VALUE)
 200     {
 201       SetConsoleTextAttribute (hstdout, norm_attr);
 202       w32_clreol ();
 203     }
 204   else
 205     fputs (sgr_end, stdout);
 206 }