gdb/ui-style.c

   1 /* Styling for ui_file
   2    Copyright (C) 2018-2019 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include "defs.h"
  20 #include "ui-style.h"
  21
  22 /* A regular expression that is used for matching ANSI terminal escape
  23    sequences.  */
  24
  25 static const char *ansi_regex_text =
  26   /* Introduction.  */
  27   "^\033\\["
  28 #define DATA_SUBEXP 1
  29   /* Capture parameter and intermediate bytes.  */
  30   "("
  31   /* Parameter bytes.  */
  32   "[\x30-\x3f]*"
  33   /* Intermediate bytes.  */
  34   "[\x20-\x2f]*"
  35   /* End the first capture.  */
  36   ")"
  37   /* The final byte.  */
  38 #define FINAL_SUBEXP 2
  39   "([\x40-\x7e])";
  40
  41 /* The number of subexpressions to allocate space for, including the
  42    "0th" whole match subexpression.  */
  43 #define NUM_SUBEXPRESSIONS 3
  44
  45 /* The compiled form of ansi_regex_text.  */
  46
  47 static regex_t ansi_regex;
  48
  49 /* This maps bright colors to RGB triples.  The index is the bright
  50    color index, starting with bright black.  The values come from
  51    xterm.  */
  52
  53 static const uint8_t bright_colors[][3] = {
  54   { 127, 127, 127 },            /* Black.  */
  55   { 255, 0, 0 },                /* Red.  */
  56   { 0, 255, 0 },                /* Green.  */
  57   { 255, 255, 0 },              /* Yellow.  */
  58   { 92, 92, 255 },              /* Blue.  */
  59   { 255, 0, 255 },              /* Magenta.  */
  60   { 0, 255, 255 },              /* Cyan.  */
  61   { 255, 255, 255 }             /* White.  */
  62 };
  63
  64 /* See ui-style.h.  */
  65
  66 bool
  67 ui_file_style::color::append_ansi (bool is_fg, std::string *str) const
  68 {
  69   if (m_simple)
  70     {
  71       if (m_value >= BLACK && m_value <= WHITE)
  72         str->append (std::to_string (m_value + (is_fg ? 30 : 40)));
  73       else if (m_value > WHITE && m_value <= WHITE + 8)
  74         str->append (std::to_string (m_value - WHITE + (is_fg ? 90 : 100)));
  75       else if (m_value != -1)
  76         {
  77           str->append (is_fg ? "38;5;" : "48;5;");
  78           str->append (std::to_string (m_value));
  79         }
  80       else
  81         return false;
  82     }
  83   else
  84     {
  85       str->append (is_fg ? "38;2;" : "48;2;");
  86       str->append (std::to_string (m_red)
  87                    + ";" + std::to_string (m_green)
  88                    + ";" + std::to_string (m_blue));
  89     }
  90   return true;
  91 }
  92
  93 /* See ui-style.h.  */
  94
  95 void
  96 ui_file_style::color::get_rgb (uint8_t *rgb) const
  97 {
  98   if (m_simple)
  99     {
 100       /* Can't call this for a basic color or NONE -- those will end
 101          up in the assert below.  */
 102       if (m_value >= 8 && m_value <= 15)
 103         memcpy (rgb, bright_colors[m_value - 8], 3 * sizeof (uint8_t));
 104       else if (m_value >= 16 && m_value <= 231)
 105         {
 106           int value = m_value;
 107           value -= 16;
 108           /* This obscure formula seems to be what terminals actually
 109              do.  */
 110           int component = value / 36;
 111           rgb[0] = component == 0 ? 0 : (55 + component * 40);
 112           value %= 36;
 113           component = value / 6;
 114           rgb[1] = component == 0 ? 0 : (55 + component * 40);
 115           value %= 6;
 116           rgb[2] = value == 0 ? 0 : (55 + value * 40);
 117         }
 118       else if (m_value >= 232)
 119         {
 120           uint8_t v = (m_value - 232) * 10 + 8;
 121           rgb[0] = v;
 122           rgb[1] = v;
 123           rgb[2] = v;
 124         }
 125       else
 126         gdb_assert_not_reached ("get_rgb called on invalid color");
 127     }
 128   else
 129     {
 130       rgb[0] = m_red;
 131       rgb[1] = m_green;
 132       rgb[2] = m_blue;
 133     }
 134 }
 135
 136 /* See ui-style.h.  */
 137
 138 std::string
 139 ui_file_style::to_ansi () const
 140 {
 141   std::string result ("\033[");
 142   bool need_semi = m_foreground.append_ansi (true, &result);
 143   if (!m_background.is_none ())
 144     {
 145       if (need_semi)
 146         result.push_back (';');
 147       m_background.append_ansi (false, &result);
 148       need_semi = true;
 149     }
 150   if (m_intensity != NORMAL)
 151     {
 152       if (need_semi)
 153         result.push_back (';');
 154       result.append (std::to_string (m_intensity));
 155       need_semi = true;
 156     }
 157   if (m_reverse)
 158     {
 159       if (need_semi)
 160         result.push_back (';');
 161       result.push_back ('7');
 162     }
 163   result.push_back ('m');
 164   return result;
 165 }
 166
 167 /* Read a ";" and a number from STRING.  Return the number of
 168    characters read and put the number into *NUM.  */
 169
 170 static bool
 171 read_semi_number (const char *string, int *idx, long *num)
 172 {
 173   if (string[*idx] != ';')
 174     return false;
 175   ++*idx;
 176   if (string[*idx] < '0' || string[*idx] > '9')
 177     return false;
 178   char *tail;
 179   *num = strtol (string + *idx, &tail, 10);
 180   *idx = tail - string;
 181   return true;
 182 }
 183
 184 /* A helper for ui_file_style::parse that reads an extended color
 185    sequence; that is, and 8- or 24- bit color.  */
 186
 187 static bool
 188 extended_color (const char *str, int *idx, ui_file_style::color *color)
 189 {
 190   long value;
 191
 192   if (!read_semi_number (str, idx, &value))
 193     return false;
 194
 195   if (value == 5)
 196     {
 197       /* 8-bit color.  */
 198       if (!read_semi_number (str, idx, &value))
 199         return false;
 200
 201       if (value >= 0 && value <= 255)
 202         *color = ui_file_style::color (value);
 203       else
 204         return false;
 205     }
 206   else if (value == 2)
 207     {
 208       /* 24-bit color.  */
 209       long r, g, b;
 210       if (!read_semi_number (str, idx, &r)
 211           || r > 255
 212           || !read_semi_number (str, idx, &g)
 213           || g > 255
 214           || !read_semi_number (str, idx, &b)
 215           || b > 255)
 216         return false;
 217       *color = ui_file_style::color (r, g, b);
 218     }
 219   else
 220     {
 221       /* Unrecognized sequence.  */
 222       return false;
 223     }
 224
 225   return true;
 226 }
 227
 228 /* See ui-style.h.  */
 229
 230 bool
 231 ui_file_style::parse (const char *buf, size_t *n_read)
 232 {
 233   regmatch_t subexps[NUM_SUBEXPRESSIONS];
 234
 235   int match = regexec (&ansi_regex, buf, ARRAY_SIZE (subexps), subexps, 0);
 236   if (match == REG_NOMATCH)
 237     {
 238       *n_read = 0;
 239       return false;
 240     }
 241   /* Other failures mean the regexp is broken.  */
 242   gdb_assert (match == 0);
 243   /* The regexp is anchored.  */
 244   gdb_assert (subexps[0].rm_so == 0);
 245   /* The final character exists.  */
 246   gdb_assert (subexps[FINAL_SUBEXP].rm_eo - subexps[FINAL_SUBEXP].rm_so == 1);
 247
 248   if (buf[subexps[FINAL_SUBEXP].rm_so] != 'm')
 249     {
 250       /* We don't handle this sequence, so just drop it.  */
 251       *n_read = subexps[0].rm_eo;
 252       return false;
 253     }
 254
 255   /* Examine each setting in the match and apply it to the result.
 256      See the Select Graphic Rendition section of
 257      https://en.wikipedia.org/wiki/ANSI_escape_code.  In essence each
 258      code is just a number, separated by ";"; there are some more
 259      wrinkles but we don't support them all..  */
 260
 261   /* "\033[m" means the same thing as "\033[0m", so handle that
 262      specially here.  */
 263   if (subexps[DATA_SUBEXP].rm_so == subexps[DATA_SUBEXP].rm_eo)
 264     *this = ui_file_style ();
 265
 266   for (regoff_t i = subexps[DATA_SUBEXP].rm_so;
 267        i < subexps[DATA_SUBEXP].rm_eo;
 268        ++i)
 269     {
 270       if (buf[i] == ';')
 271         {
 272           /* Skip.  */
 273         }
 274       else if (buf[i] >= '0' && buf[i] <= '9')
 275         {
 276           char *tail;
 277           long value = strtol (buf + i, &tail, 10);
 278           i = tail - buf;
 279
 280           switch (value)
 281             {
 282             case 0:
 283               /* Reset.  */
 284               *this = ui_file_style ();
 285               break;
 286             case 1:
 287               /* Bold.  */
 288               m_intensity = BOLD;
 289               break;
 290             case 2:
 291               /* Dim.  */
 292               m_intensity = DIM;
 293               break;
 294             case 7:
 295               /* Reverse.  */
 296               m_reverse = true;
 297               break;
 298             case 21:
 299               m_intensity = NORMAL;
 300               break;
 301             case 22:
 302               /* Normal.  */
 303               m_intensity = NORMAL;
 304               break;
 305             case 27:
 306               /* Inverse off.  */
 307               m_reverse = false;
 308               break;
 309
 310             case 30:
 311             case 31:
 312             case 32:
 313             case 33:
 314             case 34:
 315             case 35:
 316             case 36:
 317             case 37:
 318               /* Note: not 38.  */
 319             case 39:
 320               m_foreground = color (value - 30);
 321               break;
 322
 323             case 40:
 324             case 41:
 325             case 42:
 326             case 43:
 327             case 44:
 328             case 45:
 329             case 46:
 330             case 47:
 331               /* Note: not 48.  */
 332             case 49:
 333               m_background = color (value - 40);
 334               break;
 335
 336             case 90:
 337             case 91:
 338             case 92:
 339             case 93:
 340             case 94:
 341             case 95:
 342             case 96:
 343             case 97:
 344               m_foreground = color (value - 90 + 8);
 345               break;
 346
 347             case 100:
 348             case 101:
 349             case 102:
 350             case 103:
 351             case 104:
 352             case 105:
 353             case 106:
 354             case 107:
 355               m_background = color (value - 100 + 8);
 356               break;
 357
 358             case 38:
 359               /* If we can't parse the extended color, fail.  */
 360               if (!extended_color (buf, &i, &m_foreground))
 361                 {
 362                   *n_read = subexps[0].rm_eo;
 363                   return false;
 364                 }
 365               break;
 366
 367             case 48:
 368               /* If we can't parse the extended color, fail.  */
 369               if (!extended_color (buf, &i, &m_background))
 370                 {
 371                   *n_read = subexps[0].rm_eo;
 372                   return false;
 373                 }
 374               break;
 375
 376             default:
 377               /* Ignore everything else.  */
 378               break;
 379             }
 380         }
 381       else
 382         {
 383           /* Unknown, let's just ignore.  */
 384         }
 385     }
 386
 387   *n_read = subexps[0].rm_eo;
 388   return true;
 389 }
 390
 391 /* See ui-style.h.  */
 392
 393 bool
 394 skip_ansi_escape (const char *buf, int *n_read)
 395 {
 396   regmatch_t subexps[NUM_SUBEXPRESSIONS];
 397
 398   int match = regexec (&ansi_regex, buf, ARRAY_SIZE (subexps), subexps, 0);
 399   if (match == REG_NOMATCH || buf[subexps[FINAL_SUBEXP].rm_so] != 'm')
 400     return false;
 401
 402   *n_read = subexps[FINAL_SUBEXP].rm_eo;
 403   return true;
 404 }
 405
 406 void
 407 _initialize_ui_style ()
 408 {
 409   int code = regcomp (&ansi_regex, ansi_regex_text, REG_EXTENDED);
 410   /* If the regular expression was incorrect, it was a programming
 411      error.  */
 412   gdb_assert (code == 0);
 413 }