src/output.c

   1 /* GNU m4 -- A simple macro processor
   2
   3    Copyright (C) 1989, 1990, 1991, 1992, 1993, 1994, 2004, 2005, 2006,
   4    2007 Free Software Foundation, Inc.
   5
   6    This file is part of GNU M4.
   7
   8    GNU M4 is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    GNU M4 is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "m4.h"
  23
  24 #include <limits.h>
  25 #include <sys/stat.h>
  26
  27 #include "gl_avltree_oset.h"
  28
  29 /* Size of initial in-memory buffer size for diversions.  Small diversions
  30    would usually fit in.  */
  31 #define INITIAL_BUFFER_SIZE 512
  32
  33 /* Maximum value for the total of all in-memory buffer sizes for
  34    diversions.  */
  35 #define MAXIMUM_TOTAL_SIZE (512 * 1024)
  36
  37 /* Size of buffer size to use while copying files.  */
  38 #define COPY_BUFFER_SIZE (32 * 512)
  39
  40 /* Output functions.  Most of the complexity is for handling cpp like
  41    sync lines.
  42
  43    This code is fairly entangled with the code in input.c, and maybe it
  44    belongs there?  */
  45
  46 typedef struct temp_dir m4_temp_dir;
  47
  48 /* When part of diversion_table, each struct m4_diversion either
  49    represents an open file (zero size, non-NULL u.file), an in-memory
  50    buffer (non-zero size, non-NULL u.buffer), or an unused placeholder
  51    diversion (zero size, u is NULL, non-zero used indicates that a
  52    file has been created).  When not part of diversion_table, u.next
  53    is a pointer to the free_list chain.  */
  54
  55 typedef struct m4_diversion m4_diversion;
  56
  57 struct m4_diversion
  58   {
  59     union
  60       {
  61         FILE *file;             /* diversion file on disk */
  62         char *buffer;           /* in-memory diversion buffer */
  63         m4_diversion *next;     /* free-list pointer */
  64       } u;
  65     int divnum;                 /* which diversion this represents */
  66     int size;                   /* usable size before reallocation */
  67     int used;                   /* used length in characters */
  68   };
  69
  70 /* Table of diversions 1 through INT_MAX.  */
  71 static gl_oset_t diversion_table;
  72
  73 /* Diversion 0 (not part of diversion_table).  */
  74 static m4_diversion div0;
  75
  76 /* Linked list of reclaimed diversion storage.  */
  77 static m4_diversion *free_list;
  78
  79 /* Obstack from which diversion storage is allocated.  */
  80 static struct obstack diversion_storage;
  81
  82 /* Total size of all in-memory buffer sizes.  */
  83 static int total_buffer_size;
  84
  85 /* The number of the currently active diversion.  This variable is
  86    maintained for the `divnum' builtin function.  */
  87 int current_diversion;
  88
  89 /* Current output diversion, NULL if output is being currently discarded.  */
  90 static m4_diversion *output_diversion;
  91
  92 /* Values of some output_diversion fields, cached out for speed.  */
  93 static FILE *output_file;       /* current value of (file) */
  94 static char *output_cursor;     /* current value of (buffer + used) */
  95 static int output_unused;       /* current value of (size - used) */
  96
  97 /* Number of input line we are generating output for.  */
  98 int output_current_line;
  99
 100 /* Temporary directory holding all spilled diversion files.  */
 101 static m4_temp_dir *output_temp_dir;
 102
 103
 104 \f
 105 /*------------------------.
 106 | Output initialization.  |
 107 `------------------------*/
 108
 109 /* Callback for comparing list elements ELT1 and ELT2 for order in
 110    diversion_table.  */
 111 static int
 112 cmp_diversion_CB (const void *elt1, const void *elt2)
 113 {
 114   const m4_diversion *d1 = (const m4_diversion *) elt1;
 115   const m4_diversion *d2 = (const m4_diversion *) elt2;
 116   /* No need to worry about overflow, since we don't create diversions
 117      with negative divnum.  */
 118   return d1->divnum - d2->divnum;
 119 }
 120
 121 /* Callback for comparing list element ELT against THRESHOLD.  */
 122 static bool
 123 threshold_diversion_CB (const void *elt, const void *threshold)
 124 {
 125   const m4_diversion *div = (const m4_diversion *) elt;
 126   /* No need to worry about overflow, since we don't create diversions
 127      with negative divnum.  */
 128   return div->divnum >= *(const int *) threshold;
 129 }
 130
 131 void
 132 output_init (void)
 133 {
 134   diversion_table = gl_oset_create_empty (GL_AVLTREE_OSET, cmp_diversion_CB,
 135                                           NULL);
 136   div0.u.file = stdout;
 137   output_diversion = &div0;
 138   output_file = stdout;
 139   obstack_init (&diversion_storage);
 140 }
 141
 142 void
 143 output_exit (void)
 144 {
 145   /* Order is important, since we may have registered cleanup_tmpfile
 146      as an atexit handler, and it must not traverse stale memory.  */
 147   gl_oset_t table = diversion_table;
 148   diversion_table = NULL;
 149   gl_oset_free (table);
 150   obstack_free (&diversion_storage, NULL);
 151 }
 152
 153 /* Clean up any temporary directory.  Designed for use as an atexit
 154    handler, where it is not safe to call exit() recursively; so this
 155    calls _exit if a problem is encountered.  */
 156 static void
 157 cleanup_tmpfile (void)
 158 {
 159   /* Close any open diversions.  */
 160   bool fail = false;
 161
 162   if (diversion_table)
 163     {
 164       const void *elt;
 165       gl_oset_iterator_t iter = gl_oset_iterator (diversion_table);
 166       while (gl_oset_iterator_next (&iter, &elt))
 167         {
 168           m4_diversion *diversion = (m4_diversion *) elt;
 169           if (!diversion->size && diversion->u.file
 170               && close_stream_temp (diversion->u.file) != 0)
 171             {
 172               m4_warn (errno, NULL,
 173                        _("cannot clean temporary file for diversion"));
 174               fail = true;
 175             }
 176         }
 177       gl_oset_iterator_free (&iter);
 178     }
 179
 180   /* Clean up the temporary directory.  */
 181   if (cleanup_temp_dir (output_temp_dir) != 0)
 182     fail = true;
 183   if (fail)
 184     _exit (exit_failure);
 185 }
 186
 187 /* Convert DIVNUM into a temporary file name for use in m4_tmp*.  */
 188 static const char *
 189 m4_tmpname (int divnum)
 190 {
 191   static char *buffer;
 192   static char *tail;
 193   if (buffer == NULL)
 194     {
 195       tail = xasprintf ("%s/m4-%d", output_temp_dir->dir_name, INT_MAX);
 196       buffer = obstack_copy0 (&diversion_storage, tail, strlen (tail));
 197       free (tail);
 198       tail = strrchr (buffer, '-') + 1;
 199     }
 200   if (sprintf (tail, "%d", divnum) < 0)
 201     m4_error (EXIT_FAILURE, errno, NULL,
 202               _("cannot create temporary file for diversion"));
 203   return buffer;
 204 }
 205
 206 /* Create a temporary file for diversion DIVNUM open for reading and
 207    writing in a secure temp directory.  The file will be automatically
 208    closed and deleted on a fatal signal.  The file can be closed and
 209    reopened with m4_tmpclose and m4_tmpopen; when finally done with
 210    the file, close it with m4_tmpremove.  Exits on failure, so the
 211    return value is always an open file.  */
 212 static FILE *
 213 m4_tmpfile (int divnum)
 214 {
 215   const char *name;
 216   FILE *file;
 217
 218   if (output_temp_dir == NULL)
 219     {
 220       output_temp_dir = create_temp_dir ("m4-", NULL, true);
 221       if (output_temp_dir == NULL)
 222         m4_error (EXIT_FAILURE, errno, NULL,
 223                   _("cannot create temporary file for diversion"));
 224       atexit (cleanup_tmpfile);
 225     }
 226   name = m4_tmpname (divnum);
 227   register_temp_file (output_temp_dir, name);
 228   file = fopen_temp (name, O_BINARY ? "wb+" : "w+");
 229   if (file == NULL)
 230     {
 231       unregister_temp_file (output_temp_dir, name);
 232       m4_error (EXIT_FAILURE, errno, NULL,
 233                 _("cannot create temporary file for diversion"));
 234     }
 235   else if (set_cloexec_flag (fileno (file), true) != 0)
 236     m4_warn (errno, NULL, _("cannot protect diversion across forks"));
 237   return file;
 238 }
 239
 240 /* Reopen a temporary file for diversion DIVNUM for reading and
 241    writing in a secure temp directory.  Exits on failure, so the
 242    return value is always an open file.  */
 243 static FILE *
 244 m4_tmpopen (int divnum)
 245 {
 246   const char *name = m4_tmpname (divnum);
 247   FILE *file;
 248
 249   file = fopen_temp (name, O_BINARY ? "ab+" : "a+");
 250   if (file == NULL)
 251     m4_error (EXIT_FAILURE, errno, NULL,
 252               _("cannot create temporary file for diversion"));
 253   else if (set_cloexec_flag (fileno (file), true) != 0)
 254     m4_warn (errno, NULL, _("cannot protect diversion across forks"));
 255   /* POSIX states that it is undefined whether an append stream starts
 256      at offset 0 or at the end.  We want the beginning.  */
 257   else if (fseeko (file, 0, SEEK_SET) != 0)
 258     m4_error (EXIT_FAILURE, errno, NULL,
 259               _("cannot seek to beginning of diversion"));
 260   return file;
 261 }
 262
 263 /* Close, but don't delete, a temporary FILE.  */
 264 static int
 265 m4_tmpclose (FILE *file)
 266 {
 267   return close_stream_temp (file);
 268 }
 269
 270 /* Delete a closed temporary FILE for diversion DIVNUM.  */
 271 static int
 272 m4_tmpremove (int divnum)
 273 {
 274   return cleanup_temp_file (output_temp_dir, m4_tmpname (divnum));
 275 }
 276
 277 /*-----------------------------------------------------------------------.
 278 | Reorganize in-memory diversion buffers so the current diversion can    |
 279 | accomodate LENGTH more characters without further reorganization.  The |
 280 | current diversion buffer is made bigger if possible.  But to make room |
 281 | for a bigger buffer, one of the in-memory diversion buffers might have |
 282 | to be flushed to a newly created temporary file.  This flushed buffer  |
 283 | might well be the current one.                                         |
 284 `-----------------------------------------------------------------------*/
 285
 286 static void
 287 make_room_for (int length)
 288 {
 289   int wanted_size;
 290   m4_diversion *selected_diversion = NULL;
 291
 292   /* Compute needed size for in-memory buffer.  Diversions in-memory
 293      buffers start at 0 bytes, then 512, then keep doubling until it is
 294      decided to flush them to disk.  */
 295
 296   output_diversion->used = output_diversion->size - output_unused;
 297
 298   for (wanted_size = output_diversion->size;
 299        wanted_size < output_diversion->used + length;
 300        wanted_size = wanted_size == 0 ? INITIAL_BUFFER_SIZE : wanted_size * 2)
 301     ;
 302
 303   /* Check if we are exceeding the maximum amount of buffer memory.  */
 304
 305   if (total_buffer_size - output_diversion->size + wanted_size
 306       > MAXIMUM_TOTAL_SIZE)
 307     {
 308       int selected_used;
 309       char *selected_buffer;
 310       m4_diversion *diversion;
 311       int count;
 312       gl_oset_iterator_t iter;
 313       const void *elt;
 314
 315       /* Find out the buffer having most data, in view of flushing it to
 316          disk.  Fake the current buffer as having already received the
 317          projected data, while making the selection.  So, if it is
 318          selected indeed, we will flush it smaller, before it grows.  */
 319
 320       selected_diversion = output_diversion;
 321       selected_used = output_diversion->used + length;
 322
 323       iter = gl_oset_iterator (diversion_table);
 324       while (gl_oset_iterator_next (&iter, &elt))
 325         {
 326           diversion = (m4_diversion *) elt;
 327           if (diversion->used > selected_used)
 328             {
 329               selected_diversion = diversion;
 330               selected_used = diversion->used;
 331             }
 332         }
 333       gl_oset_iterator_free (&iter);
 334
 335       /* Create a temporary file, write the in-memory buffer of the
 336          diversion to this file, then release the buffer.  Zero the
 337          diversion before doing anything that can exit () (including
 338          m4_tmpfile), so that the atexit handler doesn't try to close
 339          a garbage pointer as a file.  */
 340
 341       selected_buffer = selected_diversion->u.buffer;
 342       total_buffer_size -= selected_diversion->size;
 343       selected_diversion->size = 0;
 344       selected_diversion->u.file = NULL;
 345       selected_diversion->u.file = m4_tmpfile (selected_diversion->divnum);
 346
 347       if (selected_diversion->used > 0)
 348         {
 349           count = fwrite (selected_buffer, (size_t) selected_diversion->used,
 350                           1, selected_diversion->u.file);
 351           if (count != 1)
 352             m4_error (EXIT_FAILURE, errno, NULL,
 353                       _("cannot flush diversion to temporary file"));
 354         }
 355
 356       /* Reclaim the buffer space for other diversions.  */
 357
 358       free (selected_buffer);
 359       selected_diversion->used = 1;
 360     }
 361
 362   /* Reload output_file, just in case the flushed diversion was current.  */
 363
 364   if (output_diversion == selected_diversion)
 365     {
 366       /* The flushed diversion was current indeed.  */
 367
 368       output_file = output_diversion->u.file;
 369       output_cursor = NULL;
 370       output_unused = 0;
 371     }
 372   else
 373     {
 374       /* Close any selected file since it is not the current diversion.  */
 375       if (selected_diversion)
 376         {
 377           FILE *file = selected_diversion->u.file;
 378           selected_diversion->u.file = NULL;
 379           if (m4_tmpclose (file) != 0)
 380             m4_warn (errno, NULL,
 381                      _("cannot close temporary file for diversion"));
 382         }
 383
 384       /* The current buffer may be safely reallocated.  */
 385       output_diversion->u.buffer
 386         = xrealloc (output_diversion->u.buffer, (size_t) wanted_size);
 387
 388       total_buffer_size += wanted_size - output_diversion->size;
 389       output_diversion->size = wanted_size;
 390
 391       output_cursor = output_diversion->u.buffer + output_diversion->used;
 392       output_unused = wanted_size - output_diversion->used;
 393     }
 394 }
 395
 396 /*------------------------------------------------------------------------.
 397 | Output one character CHAR, when it is known that it goes to a diversion |
 398 | file or an in-memory diversion buffer.                                  |
 399 `------------------------------------------------------------------------*/
 400
 401 #define OUTPUT_CHARACTER(Char) \
 402   if (output_file)                                                      \
 403     putc ((Char), output_file);                                         \
 404   else if (output_unused == 0)                                          \
 405     output_character_helper ((Char));                                   \
 406   else                                                                  \
 407     (output_unused--, *output_cursor++ = (Char))
 408
 409 static void
 410 output_character_helper (int character)
 411 {
 412   make_room_for (1);
 413
 414   if (output_file)
 415     putc (character, output_file);
 416   else
 417     {
 418       *output_cursor++ = character;
 419       output_unused--;
 420     }
 421 }
 422
 423 /*------------------------------------------------------------------------.
 424 | Output one TEXT having LENGTH characters, when it is known that it goes |
 425 | to a diversion file or an in-memory diversion buffer.                   |
 426 `------------------------------------------------------------------------*/
 427
 428 void
 429 output_text (const char *text, int length)
 430 {
 431   int count;
 432
 433   if (!output_diversion || !length)
 434     return;
 435
 436   if (!output_file && length > output_unused)
 437     make_room_for (length);
 438
 439   if (output_file)
 440     {
 441       count = fwrite (text, length, 1, output_file);
 442       if (count != 1)
 443         m4_error (EXIT_FAILURE, errno, NULL, _("error copying inserted file"));
 444     }
 445   else
 446     {
 447       memcpy (output_cursor, text, (size_t) length);
 448       output_cursor += length;
 449       output_unused -= length;
 450     }
 451 }
 452
 453 /*--------------------------------------------------------------------.
 454 | Add some text into an obstack OBS, taken from TEXT, having LENGTH   |
 455 | characters.  If OBS is NULL, output the text to an external file    |
 456 | or an in-memory diversion buffer instead.  If OBS is NULL, and      |
 457 | there is no output file, the text is discarded.  LINE is the line   |
 458 | where the token starts (not necessarily current_line, in the case   |
 459 | of multiline tokens).                                               |
 460 |                                                                     |
 461 | If we are generating sync lines, the output has to be examined,     |
 462 | because we need to know how much output each input line generates.  |
 463 | In general, sync lines are output whenever a single input lines     |
 464 | generates several output lines, or when several input lines do not  |
 465 | generate any output.                                                |
 466 `--------------------------------------------------------------------*/
 467
 468 void
 469 shipout_text (struct obstack *obs, const char *text, int length, int line)
 470 {
 471   static bool start_of_output_line = true;
 472   const char *cursor;
 473
 474   /* If output goes to an obstack, merely add TEXT to it.  */
 475
 476   if (obs != NULL)
 477     {
 478       obstack_grow (obs, text, length);
 479       return;
 480     }
 481
 482   /* Do nothing if TEXT should be discarded.  */
 483
 484   if (output_diversion == NULL)
 485     return;
 486
 487   /* Output TEXT to a file, or in-memory diversion buffer.  */
 488
 489   if (!sync_output)
 490     switch (length)
 491       {
 492
 493         /* In-line short texts.  */
 494
 495       case 8: OUTPUT_CHARACTER (*text); text++;
 496       case 7: OUTPUT_CHARACTER (*text); text++;
 497       case 6: OUTPUT_CHARACTER (*text); text++;
 498       case 5: OUTPUT_CHARACTER (*text); text++;
 499       case 4: OUTPUT_CHARACTER (*text); text++;
 500       case 3: OUTPUT_CHARACTER (*text); text++;
 501       case 2: OUTPUT_CHARACTER (*text); text++;
 502       case 1: OUTPUT_CHARACTER (*text);
 503       case 0:
 504         return;
 505
 506         /* Optimize longer texts.  */
 507
 508       default:
 509         output_text (text, length);
 510       }
 511   else
 512     {
 513       /* Check for syncline only at the start of a token.  Multiline
 514          tokens, and tokens that are out of sync but in the middle of
 515          the line, must wait until the next raw newline triggers a
 516          syncline.  */
 517       if (start_of_output_line)
 518         {
 519           start_of_output_line = false;
 520           output_current_line++;
 521 #ifdef DEBUG_OUTPUT
 522           xfprintf (stderr, "DEBUG: line %d, cur %d, cur out %d\n",
 523                    line, current_line, output_current_line);
 524 #endif
 525
 526           /* Output a `#line NUM' synchronization directive if needed.
 527              If output_current_line was previously given a negative
 528              value (invalidated), output `#line NUM "FILE"' instead.  */
 529
 530           if (output_current_line != line)
 531             {
 532               OUTPUT_CHARACTER ('#');
 533               OUTPUT_CHARACTER ('l');
 534               OUTPUT_CHARACTER ('i');
 535               OUTPUT_CHARACTER ('n');
 536               OUTPUT_CHARACTER ('e');
 537               OUTPUT_CHARACTER (' ');
 538               for (cursor = ntoa (line, 10); *cursor; cursor++)
 539                 OUTPUT_CHARACTER (*cursor);
 540               if (output_current_line < 1 && current_file[0] != '\0')
 541                 {
 542                   OUTPUT_CHARACTER (' ');
 543                   OUTPUT_CHARACTER ('"');
 544                   for (cursor = current_file; *cursor; cursor++)
 545                     OUTPUT_CHARACTER (*cursor);
 546                   OUTPUT_CHARACTER ('"');
 547                 }
 548               OUTPUT_CHARACTER ('\n');
 549               output_current_line = line;
 550             }
 551         }
 552
 553       /* Output the token, and track embedded newlines.  */
 554       for (; length-- > 0; text++)
 555         {
 556           if (start_of_output_line)
 557             {
 558               start_of_output_line = false;
 559               output_current_line++;
 560 #ifdef DEBUG_OUTPUT
 561               xfprintf (stderr, "DEBUG: line %d, cur %d, cur out %d\n",
 562                        line, current_line, output_current_line);
 563 #endif
 564             }
 565           OUTPUT_CHARACTER (*text);
 566           if (*text == '\n')
 567             start_of_output_line = true;
 568         }
 569     }
 570 }
 571 \f
 572 /* Functions for use by diversions.  */
 573
 574 /*--------------------------------------------------------------------------.
 575 | Make a file for diversion DIVNUM, and install it in the diversion table.  |
 576 | Grow the size of the diversion table as needed.                           |
 577 `--------------------------------------------------------------------------*/
 578
 579 /* The number of possible diversions is limited only by memory and
 580    available file descriptors (each overflowing diversion uses one).  */
 581
 582 void
 583 make_diversion (int divnum)
 584 {
 585   m4_diversion *diversion = NULL;
 586
 587   if (current_diversion == divnum)
 588     return;
 589
 590   if (output_diversion)
 591     {
 592       if (!output_diversion->size && !output_diversion->u.file)
 593         {
 594           if (!gl_oset_remove (diversion_table, output_diversion))
 595             assert (false);
 596           output_diversion->u.next = free_list;
 597           output_diversion->used = 0;
 598           free_list = output_diversion;
 599         }
 600       else if (output_diversion->size)
 601         output_diversion->used = output_diversion->size - output_unused;
 602       else if (output_diversion->used)
 603         {
 604           FILE *file = output_diversion->u.file;
 605           output_diversion->u.file = NULL;
 606           if (m4_tmpclose (file) != 0)
 607             m4_warn (errno, NULL,
 608                      _("cannot close temporary file for diversion"));
 609         }
 610       output_diversion = NULL;
 611       output_file = NULL;
 612       output_cursor = NULL;
 613       output_unused = 0;
 614     }
 615
 616   current_diversion = divnum;
 617
 618   if (divnum < 0)
 619     return;
 620
 621   if (divnum == 0)
 622     diversion = &div0;
 623   else
 624     {
 625       const void *elt;
 626       if (gl_oset_search_atleast (diversion_table, threshold_diversion_CB,
 627                                   &divnum, &elt))
 628         {
 629           m4_diversion *temp = (m4_diversion *) elt;
 630           if (temp->divnum == divnum)
 631             diversion = temp;
 632         }
 633     }
 634   if (diversion == NULL)
 635     {
 636       /* First time visiting this diversion.  */
 637       if (free_list)
 638         {
 639           diversion = free_list;
 640           free_list = diversion->u.next;
 641         }
 642       else
 643         {
 644           diversion = (m4_diversion *) obstack_alloc (&diversion_storage,
 645                                                       sizeof *diversion);
 646           diversion->size = 0;
 647           diversion->used = 0;
 648         }
 649       diversion->u.file = NULL;
 650       diversion->divnum = divnum;
 651       gl_oset_add (diversion_table, diversion);
 652     }
 653
 654   output_diversion = diversion;
 655   if (output_diversion->size)
 656     {
 657       output_cursor = output_diversion->u.buffer + output_diversion->used;
 658       output_unused = output_diversion->size - output_diversion->used;
 659     }
 660   else
 661     {
 662       if (!output_diversion->u.file && output_diversion->used)
 663         output_diversion->u.file = m4_tmpopen (output_diversion->divnum);
 664       output_file = output_diversion->u.file;
 665     }
 666   output_current_line = -1;
 667 }
 668
 669 /*-------------------------------------------------------------------.
 670 | Insert a FILE into the current output file, in the same manner     |
 671 | diversions are handled.  This allows files to be included, without |
 672 | having them rescanned by m4.                                       |
 673 `-------------------------------------------------------------------*/
 674
 675 void
 676 insert_file (FILE *file)
 677 {
 678   char buffer[COPY_BUFFER_SIZE];
 679   size_t length;
 680
 681   /* Optimize out inserting into a sink.  */
 682
 683   if (!output_diversion)
 684     return;
 685
 686   /* Insert output by big chunks.  */
 687
 688   for (;;)
 689     {
 690       length = fread (buffer, 1, COPY_BUFFER_SIZE, file);
 691       if (ferror (file))
 692         m4_error (EXIT_FAILURE, errno, NULL, _("error reading inserted file"));
 693       if (length == 0)
 694         break;
 695       output_text (buffer, length);
 696     }
 697 }
 698
 699 /*-------------------------------------------------------------------.
 700 | Insert DIVERSION (but not div0) into the current output file.  The |
 701 | diversion is NOT placed on the expansion obstack, because it must  |
 702 | not be rescanned.  When the file is closed, it is deleted by the   |
 703 | system.                                                            |
 704 `-------------------------------------------------------------------*/
 705
 706 static void
 707 insert_diversion_helper (m4_diversion *diversion)
 708 {
 709   /* Effectively undivert only if an output stream is active.  */
 710   if (output_diversion)
 711     {
 712       if (diversion->size)
 713         output_text (diversion->u.buffer, diversion->used);
 714       else
 715         {
 716           if (!diversion->u.file)
 717             diversion->u.file = m4_tmpopen (diversion->divnum);
 718           insert_file (diversion->u.file);
 719         }
 720
 721       output_current_line = -1;
 722     }
 723
 724   /* Return all space used by the diversion.  */
 725   if (diversion->size)
 726     {
 727       free (diversion->u.buffer);
 728       diversion->size = 0;
 729       diversion->used = 0;
 730     }
 731   else
 732     {
 733       if (diversion->u.file)
 734         {
 735           FILE *file = diversion->u.file;
 736           diversion->u.file = NULL;
 737           diversion->used = 0;
 738           if (m4_tmpclose (file) != 0)
 739             m4_warn (errno, NULL,
 740                      _("cannot clean temporary file for diversion"));
 741         }
 742       if (m4_tmpremove (diversion->divnum) != 0)
 743         m4_warn (errno, NULL, _("cannot clean temporary file for diversion"));
 744     }
 745   gl_oset_remove (diversion_table, diversion);
 746   diversion->u.next = free_list;
 747   free_list = diversion;
 748 }
 749
 750 /*-------------------------------------------------------------------------.
 751 | Insert diversion number DIVNUM into the current output file.  The        |
 752 | diversion is NOT placed on the expansion obstack, because it must not be |
 753 | rescanned.  When the file is closed, it is deleted by the system.        |
 754 `-------------------------------------------------------------------------*/
 755
 756 void
 757 insert_diversion (int divnum)
 758 {
 759   const void *elt;
 760
 761   /* Do not care about nonexistent diversions, and undiverting stdout
 762      or self is a no-op.  */
 763   if (divnum <= 0 || current_diversion == divnum)
 764     return;
 765   if (gl_oset_search_atleast (diversion_table, threshold_diversion_CB,
 766                               &divnum, &elt))
 767     {
 768       m4_diversion *diversion = (m4_diversion *) elt;
 769       if (diversion->divnum == divnum)
 770         insert_diversion_helper (diversion);
 771     }
 772 }
 773
 774 /*-------------------------------------------------------------------------.
 775 | Get back all diversions.  This is done just before exiting from main (), |
 776 | and from m4_undivert (), if called without arguments.                    |
 777 `-------------------------------------------------------------------------*/
 778
 779 void
 780 undivert_all (void)
 781 {
 782   const void *elt;
 783   gl_oset_iterator_t iter = gl_oset_iterator (diversion_table);
 784   while (gl_oset_iterator_next (&iter, &elt))
 785     {
 786       m4_diversion *diversion = (m4_diversion *) elt;
 787       if (diversion->divnum != current_diversion)
 788         insert_diversion_helper (diversion);
 789     }
 790   gl_oset_iterator_free (&iter);
 791 }
 792
 793 /*-------------------------------------------------------------.
 794 | Produce all diversion information in frozen format on FILE.  |
 795 `-------------------------------------------------------------*/
 796
 797 void
 798 freeze_diversions (FILE *file)
 799 {
 800   int saved_number;
 801   int last_inserted;
 802   gl_oset_iterator_t iter;
 803   const void *elt;
 804
 805   saved_number = current_diversion;
 806   last_inserted = 0;
 807   make_diversion (0);
 808   output_file = file;           /* kludge in the frozen file */
 809
 810   iter = gl_oset_iterator (diversion_table);
 811   while (gl_oset_iterator_next (&iter, &elt))
 812     {
 813       m4_diversion *diversion = (m4_diversion *) elt;;
 814       if (diversion->size || diversion->used)
 815         {
 816           if (diversion->size)
 817             xfprintf (file, "D%d,%d\n", diversion->divnum, diversion->used);
 818           else
 819             {
 820               struct stat file_stat;
 821               diversion->u.file = m4_tmpopen (diversion->divnum);
 822               if (fstat (fileno (diversion->u.file), &file_stat) < 0)
 823                 m4_error (EXIT_FAILURE, errno, NULL,
 824                           _("cannot stat diversion"));
 825               if (file_stat.st_size < 0
 826                   || file_stat.st_size != (unsigned long int) file_stat.st_size)
 827                 m4_error (EXIT_FAILURE, 0, NULL, _("diversion too large"));
 828               xfprintf (file, "D%d,%lu\n", diversion->divnum,
 829                         (unsigned long int) file_stat.st_size);
 830             }
 831
 832           insert_diversion_helper (diversion);
 833           putc ('\n', file);
 834
 835           last_inserted = diversion->divnum;
 836         }
 837     }
 838   gl_oset_iterator_free (&iter);
 839
 840   /* Save the active diversion number, if not already.  */
 841
 842   if (saved_number != last_inserted)
 843     xfprintf (file, "D%d,0\n\n", saved_number);
 844 }