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_unlocked ("Throw to key ", port);
  63   scm_write (key, port);
  64   scm_puts_unlocked (" 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 #if SCM_ENABLE_DEPRECATED
 148   if (SCM_STACKP (frame))
 149     {
 150       scm_c_issue_deprecation_warning
 151         ("Passing a stack as the first argument to `scm_display_error' is "
 152          "deprecated.  Pass a frame instead.");
 153       if (SCM_STACK_LENGTH (frame))
 154         frame = scm_stack_ref (frame, SCM_INUM0);
 155       else
 156         frame = SCM_BOOL_F;
 157     }
 158 #endif
 159
 160   scm_i_display_error (frame, port, subr, message, args, rest);
 161
 162   return SCM_UNSPECIFIED;
 163 }
 164 #undef FUNC_NAME
 165
 166
 167 typedef struct {
 168   int level;
 169   int length;
 170 } print_params_t;
 171
 172 static int n_print_params = 9;
 173 static print_params_t default_print_params[] = {
 174   { 4, 9 }, { 4, 3 },
 175   { 3, 4 }, { 3, 3 },
 176   { 2, 4 }, { 2, 3 },
 177   { 1, 4 }, { 1, 3 }, { 1, 2 }
 178 };
 179 static print_params_t *print_params = default_print_params;
 180
 181 #ifdef GUILE_DEBUG
 182 SCM_DEFINE (scm_set_print_params_x, "set-print-params!", 1, 0, 0,
 183            (SCM params),
 184             "Set the print parameters to the values from @var{params}.\n"
 185             "@var{params} must be a list of two-element lists which must\n"
 186             "hold two integer values.")
 187 #define FUNC_NAME s_scm_set_print_params_x
 188 {
 189   int i;
 190   int n;
 191   SCM ls;
 192   print_params_t *new_params;
 193
 194   SCM_VALIDATE_NONEMPTYLIST_COPYLEN (2, params, n);
 195   for (ls = params; !SCM_NULL_OR_NIL_P (ls); ls = SCM_CDR (ls))
 196     SCM_ASSERT (scm_ilength (SCM_CAR (params)) == 2
 197                 && scm_is_unsigned_integer (SCM_CAAR (ls), 0, INT_MAX)
 198                 && scm_is_unsigned_integer (SCM_CADAR (ls), 0, INT_MAX),
 199                 params,
 200                 SCM_ARG2,
 201                 s_scm_set_print_params_x);
 202   new_params = scm_malloc (n * sizeof (print_params_t));
 203   if (print_params != default_print_params)
 204     free (print_params);
 205   print_params = new_params;
 206   for (i = 0; i < n; ++i)
 207     {
 208       print_params[i].level = scm_to_int (SCM_CAAR (params));
 209       print_params[i].length = scm_to_int (SCM_CADAR (params));
 210       params = SCM_CDR (params);
 211     }
 212   n_print_params = n;
 213   return SCM_UNSPECIFIED;
 214 }
 215 #undef FUNC_NAME
 216 #endif
 217
 218 static void
 219 indent (int n, SCM port)
 220 {
 221   int i;
 222   for (i = 0; i < n; ++i)
 223     scm_putc_unlocked (' ', port);
 224 }
 225
 226 static void
 227 display_frame_expr (char *hdr, SCM exp, char *tlr, int indentation, SCM sport, SCM port, scm_print_state *pstate)
 228 {
 229   int i = 0, n;
 230   scm_t_ptob_descriptor *ptob = SCM_PORT_DESCRIPTOR (sport);
 231   do
 232     {
 233       pstate->length = print_params[i].length;
 234       ptob->seek (sport, 0, SEEK_SET);
 235       if (scm_is_pair (exp))
 236         {
 237           pstate->level = print_params[i].level - 1;
 238           scm_iprlist (hdr, exp, tlr[0], sport, pstate);
 239           scm_puts_unlocked (&tlr[1], sport);
 240         }
 241       else
 242         {
 243           pstate->level = print_params[i].level;
 244           scm_iprin1 (exp, sport, pstate);
 245         }
 246       ptob->flush (sport);
 247       n = ptob->seek (sport, 0, SEEK_CUR);
 248       ++i;
 249     }
 250   while (indentation + n > SCM_BACKTRACE_WIDTH && i < n_print_params);
 251   ptob->truncate (sport, n);
 252
 253   scm_display (scm_strport_to_string (sport), port);
 254 }
 255
 256 static void
 257 display_application (SCM frame, int indentation, SCM sport, SCM port, scm_print_state *pstate)
 258 {
 259   SCM proc = scm_frame_procedure (frame);
 260   SCM name = (scm_is_true (scm_procedure_p (proc))
 261               ? scm_procedure_name (proc)
 262               : SCM_BOOL_F);
 263   display_frame_expr ("[",
 264                       scm_cons (scm_is_true (name) ? name : proc,
 265                                 scm_frame_arguments (frame)),
 266                       "]",
 267                       indentation,
 268                       sport,
 269                       port,
 270                       pstate);
 271 }
 272
 273 SCM_DEFINE (scm_display_application, "display-application", 1, 2, 0,
 274            (SCM frame, SCM port, SCM indent),
 275             "Display a procedure application @var{frame} to the output port\n"
 276             "@var{port}. @var{indent} specifies the indentation of the\n"
 277             "output.")
 278 #define FUNC_NAME s_scm_display_application
 279 {
 280   SCM_VALIDATE_FRAME (1, frame);
 281   if (SCM_UNBNDP (port))
 282     port = scm_current_output_port ();
 283   else
 284     SCM_VALIDATE_OPOUTPORT (2, port);
 285   if (SCM_UNBNDP (indent))
 286     indent = SCM_INUM0;
 287
 288   /* Display an application. */
 289   {
 290     SCM sport, print_state;
 291     scm_print_state *pstate;
 292
 293     /* Create a string port used for adaptation of printing parameters. */
 294     sport = scm_mkstrport (SCM_INUM0, SCM_BOOL_F,
 295                            SCM_OPN | SCM_WRTNG,
 296                            FUNC_NAME);
 297
 298     /* Create a print state for printing of frames. */
 299     print_state = scm_make_print_state ();
 300     pstate = SCM_PRINT_STATE (print_state);
 301     pstate->writingp = 1;
 302     pstate->fancyp = 1;
 303
 304     display_application (frame, scm_to_int (indent), sport, port, pstate);
 305     return SCM_BOOL_T;
 306   }
 307 }
 308 #undef FUNC_NAME
 309
 310 SCM_SYMBOL (sym_base, "base");
 311
 312 static void
 313 display_backtrace_get_file_line (SCM frame, SCM *file, SCM *line)
 314 {
 315   SCM source = scm_frame_source (frame);
 316   *file = *line = SCM_BOOL_F;
 317   if (scm_is_pair (source)
 318       && scm_is_pair (scm_cdr (source))
 319       && scm_is_pair (scm_cddr (source))
 320       && !scm_is_pair (scm_cdddr (source)))
 321     {
 322       /* (addr . (filename . (line . column))), from vm compilation */
 323       *file = scm_cadr (source);
 324       *line = scm_caddr (source);
 325     }
 326 }
 327
 328 static void
 329 display_backtrace_file (frame, last_file, port, pstate)
 330      SCM frame;
 331      SCM *last_file;
 332      SCM port;
 333      scm_print_state *pstate;
 334 {
 335   SCM file, line;
 336
 337   display_backtrace_get_file_line (frame, &file, &line);
 338
 339   if (scm_is_true (scm_equal_p (file, *last_file)))
 340     return;
 341
 342   *last_file = file;
 343
 344   scm_puts_unlocked ("In ", port);
 345   if (scm_is_false (file))
 346     if (scm_is_false (line))
 347       scm_puts_unlocked ("unknown file", port);
 348     else
 349       scm_puts_unlocked ("current input", port);
 350   else
 351     {
 352       pstate->writingp = 0;
 353       scm_iprin1 (file, port, pstate);
 354       pstate->writingp = 1;
 355     }
 356   scm_puts_unlocked (":\n", port);
 357 }
 358
 359 static void
 360 display_backtrace_file_and_line (SCM frame, SCM port, scm_print_state *pstate)
 361 {
 362   SCM file, line;
 363
 364   display_backtrace_get_file_line (frame, &file, &line);
 365
 366   if (scm_is_eq (SCM_PACK (SCM_SHOW_FILE_NAME), sym_base))
 367     {
 368       if (scm_is_false (file))
 369         {
 370           if (scm_is_false (line))
 371             scm_putc_unlocked ('?', port);
 372           else
 373             scm_puts_unlocked ("<stdin>", port);
 374         }
 375       else
 376         {
 377           pstate -> writingp = 0;
 378 #ifdef HAVE_POSIX
 379           scm_iprin1 ((scm_is_string (file)?
 380                        scm_basename (file, SCM_UNDEFINED) : file),
 381                       port, pstate);
 382 #else
 383           scm_iprin1 (file, port, pstate);
 384 #endif
 385           pstate -> writingp = 1;
 386         }
 387
 388       scm_putc_unlocked (':', port);
 389     }
 390   else if (scm_is_true (line))
 391     {
 392       int i, j=0;
 393       for (i = scm_to_int (line)+1; i > 0; i = i/10, j++)
 394         ;
 395       indent (4-j, port);
 396     }
 397
 398   if (scm_is_false (line))
 399     scm_puts_unlocked ("   ?", port);
 400   else
 401     scm_intprint (scm_to_int (line) + 1, 10, port);
 402   scm_puts_unlocked (": ", port);
 403 }
 404
 405 static void
 406 display_frame (SCM frame, int n, int nfield, int indentation,
 407                SCM sport, SCM port, scm_print_state *pstate)
 408 {
 409   int i, j;
 410
 411   /* display file name and line number */
 412   if (scm_is_true (SCM_PACK (SCM_SHOW_FILE_NAME)))
 413     display_backtrace_file_and_line (frame, port, pstate);
 414
 415   /* Check size of frame number. */
 416   for (i = 0, j = n; j > 0; ++i) j /= 10;
 417
 418   /* Number indentation. */
 419   indent (nfield - (i ? i : 1), port);
 420
 421   /* Frame number. */
 422   scm_iprin1 (scm_from_int (n), port, pstate);
 423
 424   /* Indentation. */
 425   indent (indentation, port);
 426
 427   /* Display an application. */
 428   display_application (frame, nfield + 1 + indentation, sport, port, pstate);
 429   scm_putc_unlocked ('\n', port);
 430 }
 431
 432 struct display_backtrace_args {
 433   SCM stack;
 434   SCM port;
 435   SCM first;
 436   SCM depth;
 437   SCM highlight_objects;
 438 };
 439
 440 static SCM
 441 display_backtrace_body (struct display_backtrace_args *a)
 442 #define FUNC_NAME "display_backtrace_body"
 443 {
 444   int n_frames, beg, end, n, i, j;
 445   int nfield, indentation;
 446   SCM frame, sport, print_state;
 447   SCM last_file;
 448   scm_print_state *pstate;
 449
 450   a->port = SCM_COERCE_OUTPORT (a->port);
 451
 452   /* Argument checking and extraction. */
 453   SCM_VALIDATE_STACK (1, a->stack);
 454   SCM_VALIDATE_OPOUTPORT (2, a->port);
 455   n_frames = scm_to_int (scm_stack_length (a->stack));
 456   n = scm_is_integer (a->depth) ? scm_to_int (a->depth) : SCM_BACKTRACE_DEPTH;
 457   if (SCM_BACKWARDS_P)
 458     {
 459       beg = scm_is_integer (a->first) ? scm_to_int (a->first) : 0;
 460       end = beg + n - 1;
 461       if (end >= n_frames)
 462         end = n_frames - 1;
 463       n = end - beg + 1;
 464     }
 465   else
 466     {
 467       if (scm_is_integer (a->first))
 468         {
 469           beg = scm_to_int (a->first);
 470           end = beg - n + 1;
 471           if (end < 0)
 472             end = 0;
 473         }
 474       else
 475         {
 476           beg = n - 1;
 477           end = 0;
 478           if (beg >= n_frames)
 479             beg = n_frames - 1;
 480         }
 481       n = beg - end + 1;
 482     }
 483   SCM_ASSERT (beg >= 0 && beg < n_frames, a->first, SCM_ARG3, s_display_backtrace);
 484   SCM_ASSERT (n > 0, a->depth, SCM_ARG4, s_display_backtrace);
 485
 486   /* Create a string port used for adaptation of printing parameters. */
 487   sport = scm_mkstrport (SCM_INUM0, SCM_BOOL_F,
 488                          SCM_OPN | SCM_WRTNG,
 489                          FUNC_NAME);
 490
 491   /* Create a print state for printing of frames. */
 492   print_state = scm_make_print_state ();
 493   pstate = SCM_PRINT_STATE (print_state);
 494   pstate->writingp = 1;
 495   pstate->fancyp = 1;
 496   pstate->highlight_objects = a->highlight_objects;
 497
 498   /* Determine size of frame number field. */
 499   j = end;
 500   for (i = 0; j > 0; ++i) j /= 10;
 501   nfield = i ? i : 1;
 502
 503   /* Print frames. */
 504   indentation = 1;
 505   last_file = SCM_UNDEFINED;
 506   if (SCM_BACKWARDS_P)
 507     end++;
 508   else
 509     end--;
 510   for (i = beg; i != end; SCM_BACKWARDS_P ? ++i : --i)
 511     {
 512       frame = scm_stack_ref (a->stack, scm_from_int (i));
 513       if (!scm_is_eq (SCM_PACK (SCM_SHOW_FILE_NAME), sym_base))
 514         display_backtrace_file (frame, &last_file, a->port, pstate);
 515       display_frame (frame, i, nfield, indentation, sport, a->port, pstate);
 516     }
 517
 518   scm_remember_upto_here_1 (print_state);
 519
 520   return SCM_UNSPECIFIED;
 521 }
 522 #undef FUNC_NAME
 523
 524 static SCM
 525 error_during_backtrace (void *data, SCM tag, SCM throw_args)
 526 {
 527   SCM port = SCM_PACK_POINTER (data);
 528
 529   scm_puts_unlocked ("Exception thrown while printing backtrace:\n", port);
 530   scm_print_exception (port, SCM_BOOL_F, tag, throw_args);
 531
 532   return SCM_UNSPECIFIED;
 533 }
 534
 535
 536 SCM_DEFINE (scm_display_backtrace_with_highlights, "display-backtrace", 2, 3, 0,
 537             (SCM stack, SCM port, SCM first, SCM depth, SCM highlights),
 538             "Display a backtrace to the output port @var{port}.  @var{stack}\n"
 539             "is the stack to take the backtrace from, @var{first} specifies\n"
 540             "where in the stack to start and @var{depth} how many frames\n"
 541             "to display.  @var{first} and @var{depth} can be @code{#f},\n"
 542             "which means that default values will be used.\n"
 543             "If @var{highlights} is given it should be a list; the elements\n"
 544             "of this list will be highlighted wherever they appear in the\n"
 545             "backtrace.")
 546 #define FUNC_NAME s_scm_display_backtrace_with_highlights
 547 {
 548   struct display_backtrace_args a;
 549   a.stack = stack;
 550   a.port  = port;
 551   a.first = first;
 552   a.depth = depth;
 553   if (SCM_UNBNDP (highlights))
 554     a.highlight_objects = SCM_EOL;
 555   else
 556     a.highlight_objects = highlights;
 557
 558   scm_internal_catch (SCM_BOOL_T,
 559                       (scm_t_catch_body) display_backtrace_body, &a,
 560                       (scm_t_catch_handler) error_during_backtrace, SCM_UNPACK_POINTER (port));
 561
 562   return SCM_UNSPECIFIED;
 563 }
 564 #undef FUNC_NAME
 565
 566 SCM
 567 scm_display_backtrace (SCM stack, SCM port, SCM first, SCM depth)
 568 {
 569   return scm_display_backtrace_with_highlights (stack, port, first, depth,
 570                                                 SCM_EOL);
 571 }
 572
 573 SCM_VARIABLE (scm_has_shown_backtrace_hint_p_var, "has-shown-backtrace-hint?");
 574
 575 SCM_DEFINE (scm_backtrace_with_highlights, "backtrace", 0, 1, 0,
 576             (SCM highlights),
 577             "Display a backtrace of the current stack to the current\n"
 578             "output port.  If @var{highlights} is given, it should be\n"
 579             "a list; the elements of this list will be highlighted\n"
 580             "wherever they appear in the backtrace.")
 581 #define FUNC_NAME s_scm_backtrace_with_highlights
 582 {
 583   SCM port = scm_current_output_port ();
 584   SCM stack = scm_make_stack (SCM_BOOL_T, SCM_EOL);
 585
 586   if (SCM_UNBNDP (highlights))
 587     highlights = SCM_EOL;
 588
 589   scm_newline (port);
 590   scm_puts_unlocked ("Backtrace:\n", port);
 591   scm_display_backtrace_with_highlights (stack, port, SCM_BOOL_F, SCM_BOOL_F,
 592                                          highlights);
 593   scm_newline (port);
 594
 595   return SCM_UNSPECIFIED;
 596 }
 597 #undef FUNC_NAME
 598
 599 SCM
 600 scm_backtrace (void)
 601 {
 602   return scm_backtrace_with_highlights (SCM_EOL);
 603 }
 604
 605 \f
 606
 607 void
 608 scm_init_backtrace ()
 609 {
 610   scm_c_define_gsubr ("print-exception", 4, 0, 0, boot_print_exception);
 611 #include "libguile/backtrace.x"
 612 }
 613
 614 /*
 615   Local Variables:
 616   c-file-style: "gnu"
 617   End:
 618 */