libguile/backtrace.c

   1 /* Printing of backtraces and error messages
   2  * Copyright (C) 1996,1997,1998,1999,2000,2001, 2003, 2004, 2006, 2009, 2010, 2011 Free Software Foundation
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public License
   6  * as published by the Free Software Foundation; either version 3 of
   7  * the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301 USA
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include <config.h>
  22 #endif
  23
  24 #include <stdio.h>
  25 #include <ctype.h>
  26
  27 #include "libguile/_scm.h"
  28
  29 #ifdef HAVE_UNISTD_H
  30 #include <unistd.h>
  31 #endif
  32 #ifdef HAVE_IO_H
  33 #include <io.h>
  34 #endif
  35
  36 #include "libguile/deprecation.h"
  37 #include "libguile/stacks.h"
  38 #include "libguile/srcprop.h"
  39 #include "libguile/struct.h"
  40 #include "libguile/strports.h"
  41 #include "libguile/throw.h"
  42 #include "libguile/fluids.h"
  43 #include "libguile/ports.h"
  44 #include "libguile/strings.h"
  45 #include "libguile/dynwind.h"
  46 #include "libguile/frames.h"
  47
  48 #include "libguile/validate.h"
  49 #include "libguile/backtrace.h"
  50 #include "libguile/filesys.h"
  51 #include "libguile/private-options.h"
  52
  53 /* {Error reporting and backtraces}
  54  *
  55  * Note that these functions shouldn't generate errors themselves.
  56  */
  57
  58 static SCM
  59 boot_print_exception (SCM port, SCM frame, SCM key, SCM args)
  60 #define FUNC_NAME "boot-print-exception"
  61 {
  62   scm_puts ("Throw to key ", port);
  63   scm_write (key, port);
  64   scm_puts (" with args ", port);
  65   scm_write (args, port);
  66   return SCM_UNSPECIFIED;
  67 }
  68 #undef FUNC_NAME
  69
  70 SCM
  71 scm_print_exception (SCM port, SCM frame, SCM key, SCM args)
  72 #define FUNC_NAME "print-exception"
  73 {
  74   static SCM print_exception = SCM_BOOL_F;
  75
  76   SCM_VALIDATE_OPOUTPORT (1, port);
  77   if (scm_is_true (frame))
  78     SCM_VALIDATE_FRAME (2, frame);
  79   SCM_VALIDATE_SYMBOL (3, key);
  80   SCM_VALIDATE_LIST (4, args);
  81
  82   if (scm_is_false (print_exception))
  83     print_exception =
  84       scm_module_variable (scm_the_root_module (),
  85                            scm_from_latin1_symbol ("print-exception"));
  86
  87   return scm_call_4 (scm_variable_ref (print_exception),
  88                      port, frame, key, args);
  89 }
  90 #undef FUNC_NAME
  91
  92
  93 \f
  94
  95 /* Print parameters for error messages. */
  96
  97 #define DISPLAY_ERROR_MESSAGE_MAX_LEVEL   7
  98 #define DISPLAY_ERROR_MESSAGE_MAX_LENGTH 10
  99
 100 /* Print parameters for failing expressions in error messages.
 101  * (See also `print_params' below for backtrace print parameters.)
 102  */
 103
 104 #define DISPLAY_EXPRESSION_MAX_LEVEL      2
 105 #define DISPLAY_EXPRESSION_MAX_LENGTH     3
 106
 107 #undef SCM_ASSERT
 108 #define SCM_ASSERT(_cond, _arg, _pos, _subr) \
 109         if (!(_cond)) \
 110           return SCM_BOOL_F;
 111
 112
 113 void
 114 scm_display_error_message (SCM message, SCM args, SCM port)
 115 {
 116   scm_print_exception (port, SCM_BOOL_F, scm_misc_error_key,
 117                        scm_list_3 (SCM_BOOL_F, message, args));
 118 }
 119
 120
 121 /* The function scm_i_display_error prints out a detailed error message.  This
 122  * function will be called directly within libguile to signal error messages.
 123  * No parameter checks will be performed by scm_i_display_error.  Thus, User
 124  * code should rather use the function scm_display_error.
 125  */
 126 void
 127 scm_i_display_error (SCM frame, SCM port, SCM subr, SCM message, SCM args, SCM rest)
 128 {
 129   scm_print_exception (port, frame, scm_misc_error_key,
 130                        scm_list_3 (subr, message, args));
 131 }
 132
 133
 134 SCM_DEFINE (scm_display_error, "display-error", 6, 0, 0,
 135             (SCM frame, SCM port, SCM subr, SCM message, SCM args, SCM rest),
 136             "Display an error message to the output port @var{port}.\n"
 137             "@var{frame} is the frame in which the error occurred, @var{subr} is\n"
 138             "the name of the procedure in which the error occurred and\n"
 139             "@var{message} is the actual error message, which may contain\n"
 140             "formatting instructions. These will format the arguments in\n"
 141             "the list @var{args} accordingly.  @var{rest} is currently\n"
 142             "ignored.")
 143 #define FUNC_NAME s_scm_display_error
 144 {
 145   SCM_VALIDATE_OUTPUT_PORT (2, port);
 146
 147   scm_i_display_error (frame, port, subr, message, args, rest);
 148
 149   return SCM_UNSPECIFIED;
 150 }
 151 #undef FUNC_NAME
 152
 153
 154 typedef struct {
 155   int level;
 156   int length;
 157 } print_params_t;
 158
 159 static int n_print_params = 9;
 160 static print_params_t default_print_params[] = {
 161   { 4, 9 }, { 4, 3 },
 162   { 3, 4 }, { 3, 3 },
 163   { 2, 4 }, { 2, 3 },
 164   { 1, 4 }, { 1, 3 }, { 1, 2 }
 165 };
 166 static print_params_t *print_params = default_print_params;
 167
 168 #ifdef GUILE_DEBUG
 169 SCM_DEFINE (scm_set_print_params_x, "set-print-params!", 1, 0, 0,
 170            (SCM params),
 171             "Set the print parameters to the values from @var{params}.\n"
 172             "@var{params} must be a list of two-element lists which must\n"
 173             "hold two integer values.")
 174 #define FUNC_NAME s_scm_set_print_params_x
 175 {
 176   int i;
 177   int n;
 178   SCM ls;
 179   print_params_t *new_params;
 180
 181   SCM_VALIDATE_NONEMPTYLIST_COPYLEN (2, params, n);
 182   for (ls = params; !SCM_NULL_OR_NIL_P (ls); ls = SCM_CDR (ls))
 183     SCM_ASSERT (scm_ilength (SCM_CAR (params)) == 2
 184                 && scm_is_unsigned_integer (SCM_CAAR (ls), 0, INT_MAX)
 185                 && scm_is_unsigned_integer (SCM_CADAR (ls), 0, INT_MAX),
 186                 params,
 187                 SCM_ARG2,
 188                 s_scm_set_print_params_x);
 189   new_params = scm_malloc (n * sizeof (print_params_t));
 190   if (print_params != default_print_params)
 191     free (print_params);
 192   print_params = new_params;
 193   for (i = 0; i < n; ++i)
 194     {
 195       print_params[i].level = scm_to_int (SCM_CAAR (params));
 196       print_params[i].length = scm_to_int (SCM_CADAR (params));
 197       params = SCM_CDR (params);
 198     }
 199   n_print_params = n;
 200   return SCM_UNSPECIFIED;
 201 }
 202 #undef FUNC_NAME
 203 #endif
 204
 205 static void
 206 indent (int n, SCM port)
 207 {
 208   int i;
 209   for (i = 0; i < n; ++i)
 210     scm_putc (' ', port);
 211 }
 212
 213 static void
 214 display_frame_expr (char *hdr, SCM exp, char *tlr, int indentation, SCM sport, SCM port, scm_print_state *pstate)
 215 {
 216   int i = 0, n;
 217   scm_t_ptob_descriptor *ptob = scm_ptobs + SCM_PTOBNUM (sport);
 218   do
 219     {
 220       pstate->length = print_params[i].length;
 221       ptob->seek (sport, 0, SEEK_SET);
 222       if (scm_is_pair (exp))
 223         {
 224           pstate->level = print_params[i].level - 1;
 225           scm_iprlist (hdr, exp, tlr[0], sport, pstate);
 226           scm_puts (&tlr[1], sport);
 227         }
 228       else
 229         {
 230           pstate->level = print_params[i].level;
 231           scm_iprin1 (exp, sport, pstate);
 232         }
 233       ptob->flush (sport);
 234       n = ptob->seek (sport, 0, SEEK_CUR);
 235       ++i;
 236     }
 237   while (indentation + n > SCM_BACKTRACE_WIDTH && i < n_print_params);
 238   ptob->truncate (sport, n);
 239
 240   scm_display (scm_strport_to_string (sport), port);
 241 }
 242
 243 static void
 244 display_application (SCM frame, int indentation, SCM sport, SCM port, scm_print_state *pstate)
 245 {
 246   SCM proc = scm_frame_procedure (frame);
 247   SCM name = (scm_is_true (scm_procedure_p (proc))
 248               ? scm_procedure_name (proc)
 249               : SCM_BOOL_F);
 250   display_frame_expr ("[",
 251                       scm_cons (scm_is_true (name) ? name : proc,
 252                                 scm_frame_arguments (frame)),
 253                       "]",
 254                       indentation,
 255                       sport,
 256                       port,
 257                       pstate);
 258 }
 259
 260 SCM_DEFINE (scm_display_application, "display-application", 1, 2, 0,
 261            (SCM frame, SCM port, SCM indent),
 262             "Display a procedure application @var{frame} to the output port\n"
 263             "@var{port}. @var{indent} specifies the indentation of the\n"
 264             "output.")
 265 #define FUNC_NAME s_scm_display_application
 266 {
 267   SCM_VALIDATE_FRAME (1, frame);
 268   if (SCM_UNBNDP (port))
 269     port = scm_current_output_port ();
 270   else
 271     SCM_VALIDATE_OPOUTPORT (2, port);
 272   if (SCM_UNBNDP (indent))
 273     indent = SCM_INUM0;
 274
 275   /* Display an application. */
 276   {
 277     SCM sport, print_state;
 278     scm_print_state *pstate;
 279
 280     /* Create a string port used for adaptation of printing parameters. */
 281     sport = scm_mkstrport (SCM_INUM0,
 282                            scm_make_string (scm_from_int (240),
 283                                             SCM_UNDEFINED),
 284                            SCM_OPN | SCM_WRTNG,
 285                            FUNC_NAME);
 286
 287     /* Create a print state for printing of frames. */
 288     print_state = scm_make_print_state ();
 289     pstate = SCM_PRINT_STATE (print_state);
 290     pstate->writingp = 1;
 291     pstate->fancyp = 1;
 292
 293     display_application (frame, scm_to_int (indent), sport, port, pstate);
 294     return SCM_BOOL_T;
 295   }
 296 }
 297 #undef FUNC_NAME
 298
 299 SCM_SYMBOL (sym_base, "base");
 300
 301 static void
 302 display_backtrace_get_file_line (SCM frame, SCM *file, SCM *line)
 303 {
 304   SCM source = scm_frame_source (frame);
 305   *file = *line = SCM_BOOL_F;
 306   if (scm_is_pair (source)
 307       && scm_is_pair (scm_cdr (source))
 308       && scm_is_pair (scm_cddr (source))
 309       && !scm_is_pair (scm_cdddr (source)))
 310     {
 311       /* (addr . (filename . (line . column))), from vm compilation */
 312       *file = scm_cadr (source);
 313       *line = scm_caddr (source);
 314     }
 315 }
 316
 317 static void
 318 display_backtrace_file (frame, last_file, port, pstate)
 319      SCM frame;
 320      SCM *last_file;
 321      SCM port;
 322      scm_print_state *pstate;
 323 {
 324   SCM file, line;
 325
 326   display_backtrace_get_file_line (frame, &file, &line);
 327
 328   if (scm_is_true (scm_equal_p (file, *last_file)))
 329     return;
 330
 331   *last_file = file;
 332
 333   scm_puts ("In ", port);
 334   if (scm_is_false (file))
 335     if (scm_is_false (line))
 336       scm_puts ("unknown file", port);
 337     else
 338       scm_puts ("current input", port);
 339   else
 340     {
 341       pstate->writingp = 0;
 342       scm_iprin1 (file, port, pstate);
 343       pstate->writingp = 1;
 344     }
 345   scm_puts (":\n", port);
 346 }
 347
 348 static void
 349 display_backtrace_file_and_line (SCM frame, SCM port, scm_print_state *pstate)
 350 {
 351   SCM file, line;
 352
 353   display_backtrace_get_file_line (frame, &file, &line);
 354
 355   if (scm_is_eq (SCM_PACK (SCM_SHOW_FILE_NAME), sym_base))
 356     {
 357       if (scm_is_false (file))
 358         {
 359           if (scm_is_false (line))
 360             scm_putc ('?', port);
 361           else
 362             scm_puts ("<stdin>", port);
 363         }
 364       else
 365         {
 366           pstate -> writingp = 0;
 367 #ifdef HAVE_POSIX
 368           scm_iprin1 ((scm_is_string (file)?
 369                        scm_basename (file, SCM_UNDEFINED) : file),
 370                       port, pstate);
 371 #else
 372           scm_iprin1 (file, port, pstate);
 373 #endif
 374           pstate -> writingp = 1;
 375         }
 376
 377       scm_putc (':', port);
 378     }
 379   else if (scm_is_true (line))
 380     {
 381       int i, j=0;
 382       for (i = scm_to_int (line)+1; i > 0; i = i/10, j++)
 383         ;
 384       indent (4-j, port);
 385     }
 386
 387   if (scm_is_false (line))
 388     scm_puts ("   ?", port);
 389   else
 390     scm_intprint (scm_to_int (line) + 1, 10, port);
 391   scm_puts (": ", port);
 392 }
 393
 394 static void
 395 display_frame (SCM frame, int n, int nfield, int indentation,
 396                SCM sport, SCM port, scm_print_state *pstate)
 397 {
 398   int i, j;
 399
 400   /* display file name and line number */
 401   if (scm_is_true (SCM_PACK (SCM_SHOW_FILE_NAME)))
 402     display_backtrace_file_and_line (frame, port, pstate);
 403
 404   /* Check size of frame number. */
 405   for (i = 0, j = n; j > 0; ++i) j /= 10;
 406
 407   /* Number indentation. */
 408   indent (nfield - (i ? i : 1), port);
 409
 410   /* Frame number. */
 411   scm_iprin1 (scm_from_int (n), port, pstate);
 412
 413   /* Indentation. */
 414   indent (indentation, port);
 415
 416   /* Display an application. */
 417   display_application (frame, nfield + 1 + indentation, sport, port, pstate);
 418   scm_putc ('\n', port);
 419 }
 420
 421 struct display_backtrace_args {
 422   SCM stack;
 423   SCM port;
 424   SCM first;
 425   SCM depth;
 426   SCM highlight_objects;
 427 };
 428
 429 static SCM
 430 display_backtrace_body (struct display_backtrace_args *a)
 431 #define FUNC_NAME "display_backtrace_body"
 432 {
 433   int n_frames, beg, end, n, i, j;
 434   int nfield, indent_p, indentation;
 435   SCM frame, sport, print_state;
 436   SCM last_file;
 437   scm_print_state *pstate;
 438
 439   a->port = SCM_COERCE_OUTPORT (a->port);
 440
 441   /* Argument checking and extraction. */
 442   SCM_VALIDATE_STACK (1, a->stack);
 443   SCM_VALIDATE_OPOUTPORT (2, a->port);
 444   n_frames = scm_to_int (scm_stack_length (a->stack));
 445   n = scm_is_integer (a->depth) ? scm_to_int (a->depth) : SCM_BACKTRACE_DEPTH;
 446   if (SCM_BACKWARDS_P)
 447     {
 448       beg = scm_is_integer (a->first) ? scm_to_int (a->first) : 0;
 449       end = beg + n - 1;
 450       if (end >= n_frames)
 451         end = n_frames - 1;
 452       n = end - beg + 1;
 453     }
 454   else
 455     {
 456       if (scm_is_integer (a->first))
 457         {
 458           beg = scm_to_int (a->first);
 459           end = beg - n + 1;
 460           if (end < 0)
 461             end = 0;
 462         }
 463       else
 464         {
 465           beg = n - 1;
 466           end = 0;
 467           if (beg >= n_frames)
 468             beg = n_frames - 1;
 469         }
 470       n = beg - end + 1;
 471     }
 472   SCM_ASSERT (beg >= 0 && beg < n_frames, a->first, SCM_ARG3, s_display_backtrace);
 473   SCM_ASSERT (n > 0, a->depth, SCM_ARG4, s_display_backtrace);
 474
 475   /* Create a string port used for adaptation of printing parameters. */
 476   sport = scm_mkstrport (SCM_INUM0,
 477                          scm_make_string (scm_from_int (240), SCM_UNDEFINED),
 478                          SCM_OPN | SCM_WRTNG,
 479                          FUNC_NAME);
 480
 481   /* Create a print state for printing of frames. */
 482   print_state = scm_make_print_state ();
 483   pstate = SCM_PRINT_STATE (print_state);
 484   pstate->writingp = 1;
 485   pstate->fancyp = 1;
 486   pstate->highlight_objects = a->highlight_objects;
 487
 488   /* First find out if it's reasonable to do indentation. */
 489   indent_p = 0;
 490
 491   /* Determine size of frame number field. */
 492   j = end;
 493   for (i = 0; j > 0; ++i) j /= 10;
 494   nfield = i ? i : 1;
 495
 496   /* Print frames. */
 497   indentation = 1;
 498   last_file = SCM_UNDEFINED;
 499   if (SCM_BACKWARDS_P)
 500     end++;
 501   else
 502     end--;
 503   for (i = beg; i != end; SCM_BACKWARDS_P ? ++i : --i)
 504     {
 505       frame = scm_stack_ref (a->stack, scm_from_int (i));
 506       if (!scm_is_eq (SCM_PACK (SCM_SHOW_FILE_NAME), sym_base))
 507         display_backtrace_file (frame, &last_file, a->port, pstate);
 508       display_frame (frame, i, nfield, indentation, sport, a->port, pstate);
 509     }
 510
 511   scm_remember_upto_here_1 (print_state);
 512
 513   return SCM_UNSPECIFIED;
 514 }
 515 #undef FUNC_NAME
 516
 517 static SCM
 518 error_during_backtrace (void *data, SCM tag, SCM throw_args)
 519 {
 520   SCM port = PTR2SCM (data);
 521
 522   scm_puts ("Exception thrown while printing backtrace:\n", port);
 523   scm_print_exception (port, SCM_BOOL_F, tag, throw_args);
 524
 525   return SCM_UNSPECIFIED;
 526 }
 527
 528
 529 SCM_DEFINE (scm_display_backtrace_with_highlights, "display-backtrace", 2, 3, 0,
 530             (SCM stack, SCM port, SCM first, SCM depth, SCM highlights),
 531             "Display a backtrace to the output port @var{port}.  @var{stack}\n"
 532             "is the stack to take the backtrace from, @var{first} specifies\n"
 533             "where in the stack to start and @var{depth} how many frames\n"
 534             "to display.  @var{first} and @var{depth} can be @code{#f},\n"
 535             "which means that default values will be used.\n"
 536             "If @var{highlights} is given it should be a list; the elements\n"
 537             "of this list will be highlighted wherever they appear in the\n"
 538             "backtrace.")
 539 #define FUNC_NAME s_scm_display_backtrace_with_highlights
 540 {
 541   struct display_backtrace_args a;
 542   a.stack = stack;
 543   a.port  = port;
 544   a.first = first;
 545   a.depth = depth;
 546   if (SCM_UNBNDP (highlights))
 547     a.highlight_objects = SCM_EOL;
 548   else
 549     a.highlight_objects = highlights;
 550
 551   scm_internal_catch (SCM_BOOL_T,
 552                       (scm_t_catch_body) display_backtrace_body, &a,
 553                       (scm_t_catch_handler) error_during_backtrace, SCM2PTR (port));
 554
 555   return SCM_UNSPECIFIED;
 556 }
 557 #undef FUNC_NAME
 558
 559 SCM
 560 scm_display_backtrace (SCM stack, SCM port, SCM first, SCM depth)
 561 {
 562   return scm_display_backtrace_with_highlights (stack, port, first, depth,
 563                                                 SCM_EOL);
 564 }
 565
 566 SCM_VARIABLE (scm_has_shown_backtrace_hint_p_var, "has-shown-backtrace-hint?");
 567
 568 SCM_DEFINE (scm_backtrace_with_highlights, "backtrace", 0, 1, 0,
 569             (SCM highlights),
 570             "Display a backtrace of the current stack to the current\n"
 571             "output port.  If @var{highlights} is given, it should be\n"
 572             "a list; the elements of this list will be highlighted\n"
 573             "wherever they appear in the backtrace.")
 574 #define FUNC_NAME s_scm_backtrace_with_highlights
 575 {
 576   SCM port = scm_current_output_port ();
 577   SCM stack = scm_make_stack (SCM_BOOL_T, SCM_EOL);
 578
 579   if (SCM_UNBNDP (highlights))
 580     highlights = SCM_EOL;
 581
 582   scm_newline (port);
 583   scm_puts ("Backtrace:\n", port);
 584   scm_display_backtrace_with_highlights (stack, port, SCM_BOOL_F, SCM_BOOL_F,
 585                                          highlights);
 586   scm_newline (port);
 587
 588   return SCM_UNSPECIFIED;
 589 }
 590 #undef FUNC_NAME
 591
 592 SCM
 593 scm_backtrace (void)
 594 {
 595   return scm_backtrace_with_highlights (SCM_EOL);
 596 }
 597
 598 \f
 599
 600 void
 601 scm_init_backtrace ()
 602 {
 603   scm_c_define_gsubr ("print-exception", 4, 0, 0, boot_print_exception);
 604 #include "libguile/backtrace.x"
 605 }
 606
 607 /*
 608   Local Variables:
 609   c-file-style: "gnu"
 610   End:
 611 */