src/diffviewer/ydiff.c

   1 /*
   2    File difference viewer
   3
   4    Copyright (C) 2007-2025
   5    Free Software Foundation, Inc.
   6
   7    Written by:
   8    Daniel Borca <dborca@yahoo.com>, 2007
   9    Slava Zanko <slavazanko@gmail.com>, 2010, 2013
  10    Andrew Borodin <aborodin@vmail.ru>, 2010-2022
  11    Ilia Maslakov <il.smind@gmail.com>, 2010
  12
  13    This file is part of the Midnight Commander.
  14
  15    The Midnight Commander is free software: you can redistribute it
  16    and/or modify it under the terms of the GNU General Public License as
  17    published by the Free Software Foundation, either version 3 of the License,
  18    or (at your option) any later version.
  19
  20    The Midnight Commander is distributed in the hope that it will be useful,
  21    but WITHOUT ANY WARRANTY; without even the implied warranty of
  22    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23    GNU General Public License for more details.
  24
  25    You should have received a copy of the GNU General Public License
  26    along with this program.  If not, see <https://www.gnu.org/licenses/>.
  27  */
  28
  29 #include <config.h>
  30
  31 #include <ctype.h>
  32 #include <errno.h>
  33 #include <stddef.h>  // ptrdiff_t
  34 #include <stdlib.h>
  35 #include <sys/stat.h>
  36 #include <sys/types.h>
  37 #include <sys/wait.h>
  38
  39 #include "lib/global.h"
  40 #include "lib/tty/tty.h"
  41 #include "lib/tty/color.h"
  42 #include "lib/tty/key.h"
  43 #include "lib/skin.h"  // EDITOR_NORMAL_COLOR
  44 #include "lib/vfs/vfs.h"
  45 #include "lib/util.h"
  46 #include "lib/widget.h"
  47 #include "lib/strutil.h"
  48 #ifdef HAVE_CHARSET
  49 #    include "lib/charsets.h"
  50 #endif
  51 #include "lib/event.h"  // mc_event_raise()
  52
  53 #include "src/filemanager/cmd.h"  // edit_file_at_line()
  54 #include "src/filemanager/panel.h"
  55 #include "src/filemanager/layout.h"  // Needed for get_current_index and get_other_panel
  56
  57 #include "src/execute.h"  // toggle_subshell()
  58 #include "src/keymap.h"
  59 #include "src/setup.h"
  60 #include "src/history.h"
  61 #ifdef HAVE_CHARSET
  62 #    include "src/selcodepage.h"
  63 #endif
  64
  65 #include "ydiff.h"
  66 #include "internal.h"
  67
  68 /*** global variables ****************************************************************************/
  69
  70 /*** file scope macro definitions ****************************************************************/
  71
  72 #define FILE_READ_BUF  4096
  73 #define FILE_FLAG_TEMP (1 << 0)
  74
  75 #define ADD_CH         '+'
  76 #define DEL_CH         '-'
  77 #define CHG_CH         '*'
  78 #define EQU_CH         ' '
  79
  80 #define HDIFF_ENABLE   1
  81 #define HDIFF_MINCTX   5
  82 #define HDIFF_DEPTH    10
  83
  84 #define FILE_DIRTY(fs)                                                                             \
  85     do                                                                                             \
  86     {                                                                                              \
  87         (fs)->pos = 0;                                                                             \
  88         (fs)->len = 0;                                                                             \
  89     }                                                                                              \
  90     while (0)
  91
  92 /*** file scope type declarations ****************************************************************/
  93
  94 typedef enum
  95 {
  96     FROM_LEFT_TO_RIGHT,
  97     FROM_RIGHT_TO_LEFT
  98 } action_direction_t;
  99
 100 /*** forward declarations (file scope functions) *************************************************/
 101
 102 /*** file scope variables ************************************************************************/
 103
 104 /* --------------------------------------------------------------------------------------------- */
 105 /*** file scope functions ************************************************************************/
 106 /* --------------------------------------------------------------------------------------------- */
 107
 108 static inline int
 109 TAB_SKIP (int ts, int pos)
 110 {
 111     if (ts > 0 && ts < 9)
 112         return ts - pos % ts;
 113     else
 114         return 8 - pos % 8;
 115 }
 116
 117 /* --------------------------------------------------------------------------------------------- */
 118
 119 /**
 120  * Fill buffer by spaces
 121  *
 122  * @param buf buffer
 123  * @param n number of spaces
 124  * @param zero_terminate add a nul after @n spaces
 125  */
 126 static void
 127 fill_by_space (char *buf, size_t n, gboolean zero_terminate)
 128 {
 129     memset (buf, ' ', n);
 130     if (zero_terminate)
 131         buf[n] = '\0';
 132 }
 133
 134 /* --------------------------------------------------------------------------------------------- */
 135
 136 static gboolean
 137 rewrite_backup_content (const vfs_path_t *from_file_name_vpath, const char *to_file_name)
 138 {
 139     FILE *backup_fd;
 140     char *contents;
 141     gsize length;
 142     const char *from_file_name;
 143
 144     from_file_name = vfs_path_get_last_path_str (from_file_name_vpath);
 145     if (!g_file_get_contents (from_file_name, &contents, &length, NULL))
 146         return FALSE;
 147
 148     backup_fd = fopen (to_file_name, "w");
 149     if (backup_fd == NULL)
 150     {
 151         g_free (contents);
 152         return FALSE;
 153     }
 154
 155     length = fwrite ((const void *) contents, length, 1, backup_fd);
 156
 157     fflush (backup_fd);
 158     fclose (backup_fd);
 159     g_free (contents);
 160     return TRUE;
 161 }
 162
 163 /* buffered I/O ************************************************************* */
 164
 165 /**
 166  * Try to open a temporary file.
 167  * @note the name is not altered if this function fails
 168  *
 169  * @param[out] name address of a pointer to store the temporary name
 170  * @return file descriptor on success, negative on error
 171  */
 172
 173 static int
 174 open_temp (void **name)
 175 {
 176     int fd;
 177     vfs_path_t *diff_file_name = NULL;
 178
 179     fd = mc_mkstemps (&diff_file_name, "mcdiff", NULL);
 180     if (fd == -1)
 181     {
 182         message (D_ERROR, MSG_ERROR, _ ("Cannot create temporary diff file\n%s"),
 183                  unix_error_string (errno));
 184         return -1;
 185     }
 186
 187     *name = vfs_path_free (diff_file_name, FALSE);
 188     return fd;
 189 }
 190
 191 /* --------------------------------------------------------------------------------------------- */
 192
 193 /**
 194  * Allocate file structure and associate file descriptor to it.
 195  *
 196  * @param fd file descriptor
 197  * @return file structure
 198  */
 199
 200 static FBUF *
 201 dview_fdopen (int fd)
 202 {
 203     FBUF *fs;
 204
 205     if (fd < 0)
 206         return NULL;
 207
 208     fs = g_try_malloc (sizeof (FBUF));
 209     if (fs == NULL)
 210         return NULL;
 211
 212     fs->buf = g_try_malloc (FILE_READ_BUF);
 213     if (fs->buf == NULL)
 214     {
 215         g_free (fs);
 216         return NULL;
 217     }
 218
 219     fs->fd = fd;
 220     FILE_DIRTY (fs);
 221     fs->flags = 0;
 222     fs->data = NULL;
 223
 224     return fs;
 225 }
 226
 227 /* --------------------------------------------------------------------------------------------- */
 228
 229 /**
 230  * Free file structure without closing the file.
 231  *
 232  * @param fs file structure
 233  * @return 0 on success, non-zero on error
 234  */
 235
 236 static int
 237 dview_ffree (FBUF *fs)
 238 {
 239     int rv = 0;
 240
 241     if ((fs->flags & FILE_FLAG_TEMP) != 0)
 242     {
 243         rv = unlink (fs->data);
 244         g_free (fs->data);
 245     }
 246     g_free (fs->buf);
 247     g_free (fs);
 248     return rv;
 249 }
 250
 251 /* --------------------------------------------------------------------------------------------- */
 252
 253 /**
 254  * Open a binary temporary file in R/W mode.
 255  * @note the file will be deleted when closed
 256  *
 257  * @return file structure
 258  */
 259 static FBUF *
 260 dview_ftemp (void)
 261 {
 262     int fd;
 263     FBUF *fs;
 264
 265     fs = dview_fdopen (0);
 266     if (fs == NULL)
 267         return NULL;
 268
 269     fd = open_temp (&fs->data);
 270     if (fd < 0)
 271     {
 272         dview_ffree (fs);
 273         return NULL;
 274     }
 275
 276     fs->fd = fd;
 277     fs->flags = FILE_FLAG_TEMP;
 278     return fs;
 279 }
 280
 281 /* --------------------------------------------------------------------------------------------- */
 282
 283 /**
 284  * Open a binary file in specified mode.
 285  *
 286  * @param filename file name
 287  * @param flags open mode, a combination of O_RDONLY, O_WRONLY, O_RDWR
 288  *
 289  * @return file structure
 290  */
 291
 292 static FBUF *
 293 dview_fopen (const char *filename, int flags)
 294 {
 295     int fd;
 296     FBUF *fs;
 297
 298     fs = dview_fdopen (0);
 299     if (fs == NULL)
 300         return NULL;
 301
 302     fd = open (filename, flags);
 303     if (fd < 0)
 304     {
 305         dview_ffree (fs);
 306         return NULL;
 307     }
 308
 309     fs->fd = fd;
 310     return fs;
 311 }
 312
 313 /* --------------------------------------------------------------------------------------------- */
 314
 315 /**
 316  * Read a line of bytes from file until newline or EOF.
 317  * @note does not stop on null-byte
 318  * @note buf will not be null-terminated
 319  *
 320  * @param buf destination buffer
 321  * @param size size of buffer
 322  * @param fs file structure
 323  *
 324  * @return number of bytes read
 325  */
 326
 327 static size_t
 328 dview_fgets (char *buf, size_t size, FBUF *fs)
 329 {
 330     size_t j = 0;
 331
 332     do
 333     {
 334         int i;
 335         gboolean stop = FALSE;
 336
 337         for (i = fs->pos; j < size && i < fs->len && !stop; i++, j++)
 338         {
 339             buf[j] = fs->buf[i];
 340             if (buf[j] == '\n')
 341                 stop = TRUE;
 342         }
 343         fs->pos = i;
 344
 345         if (j == size || stop)
 346             break;
 347
 348         fs->pos = 0;
 349         fs->len = read (fs->fd, fs->buf, FILE_READ_BUF);
 350     }
 351     while (fs->len > 0);
 352
 353     return j;
 354 }
 355
 356 /* --------------------------------------------------------------------------------------------- */
 357
 358 /**
 359  * Seek into file.
 360  * @note avoids thrashing read cache when possible
 361  *
 362  * @param fs file structure
 363  * @param off offset
 364  * @param whence seek directive: SEEK_SET, SEEK_CUR or SEEK_END
 365  *
 366  * @return position in file, starting from beginning
 367  */
 368
 369 static off_t
 370 dview_fseek (FBUF *fs, off_t off, int whence)
 371 {
 372     off_t rv;
 373
 374     if (fs->len != 0 && whence != SEEK_END)
 375     {
 376         rv = lseek (fs->fd, 0, SEEK_CUR);
 377         if (rv != -1)
 378         {
 379             if (whence == SEEK_CUR)
 380             {
 381                 whence = SEEK_SET;
 382                 off += rv - fs->len + fs->pos;
 383             }
 384             if (off - rv >= -fs->len && off - rv <= 0)
 385             {
 386                 fs->pos = fs->len + off - rv;
 387                 return off;
 388             }
 389         }
 390     }
 391
 392     rv = lseek (fs->fd, off, whence);
 393     if (rv != -1)
 394         FILE_DIRTY (fs);
 395     return rv;
 396 }
 397
 398 /* --------------------------------------------------------------------------------------------- */
 399
 400 /**
 401  * Seek to the beginning of file, thrashing read cache.
 402  *
 403  * @param fs file structure
 404  *
 405  * @return 0 if success, non-zero on error
 406  */
 407
 408 static off_t
 409 dview_freset (FBUF *fs)
 410 {
 411     off_t rv;
 412
 413     rv = lseek (fs->fd, 0, SEEK_SET);
 414     if (rv != -1)
 415         FILE_DIRTY (fs);
 416     return rv;
 417 }
 418
 419 /* --------------------------------------------------------------------------------------------- */
 420
 421 /**
 422  * Write bytes to file.
 423  * @note thrashes read cache
 424  *
 425  * @param fs file structure
 426  * @param buf source buffer
 427  * @param size size of buffer
 428  *
 429  * @return number of written bytes, -1 on error
 430  */
 431
 432 static ssize_t
 433 dview_fwrite (FBUF *fs, const char *buf, size_t size)
 434 {
 435     ssize_t rv;
 436
 437     rv = write (fs->fd, buf, size);
 438     if (rv >= 0)
 439         FILE_DIRTY (fs);
 440     return rv;
 441 }
 442
 443 /* --------------------------------------------------------------------------------------------- */
 444
 445 /**
 446  * Truncate file to the current position.
 447  * @note thrashes read cache
 448  *
 449  * @param fs file structure
 450  *
 451  * @return current file size on success, negative on error
 452  */
 453
 454 static off_t
 455 dview_ftrunc (FBUF *fs)
 456 {
 457     off_t off;
 458
 459     off = lseek (fs->fd, 0, SEEK_CUR);
 460     if (off != -1)
 461     {
 462         int rv;
 463
 464         rv = ftruncate (fs->fd, off);
 465         if (rv != 0)
 466             off = -1;
 467         else
 468             FILE_DIRTY (fs);
 469     }
 470     return off;
 471 }
 472
 473 /* --------------------------------------------------------------------------------------------- */
 474
 475 /**
 476  * Close file.
 477  * @note if this is temporary file, it is deleted
 478  *
 479  * @param fs file structure
 480  * @return 0 on success, non-zero on error
 481  */
 482
 483 static int
 484 dview_fclose (FBUF *fs)
 485 {
 486     int rv = -1;
 487
 488     if (fs != NULL)
 489     {
 490         rv = close (fs->fd);
 491         dview_ffree (fs);
 492     }
 493
 494     return rv;
 495 }
 496
 497 /* --------------------------------------------------------------------------------------------- */
 498
 499 /**
 500  * Create pipe stream to process.
 501  *
 502  * @param cmd shell command line
 503  * @param flags open mode, either O_RDONLY or O_WRONLY
 504  *
 505  * @return file structure
 506  */
 507
 508 static FBUF *
 509 dview_popen (const char *cmd, int flags)
 510 {
 511     FILE *f;
 512     FBUF *fs;
 513     const char *type = NULL;
 514
 515     if (flags == O_RDONLY)
 516         type = "r";
 517     else if (flags == O_WRONLY)
 518         type = "w";
 519
 520     if (type == NULL)
 521         return NULL;
 522
 523     fs = dview_fdopen (0);
 524     if (fs == NULL)
 525         return NULL;
 526
 527     f = popen (cmd, type);
 528     if (f == NULL)
 529     {
 530         dview_ffree (fs);
 531         return NULL;
 532     }
 533
 534     fs->fd = fileno (f);
 535     fs->data = f;
 536     return fs;
 537 }
 538
 539 /* --------------------------------------------------------------------------------------------- */
 540
 541 /**
 542  * Close pipe stream.
 543  *
 544  * @param fs structure
 545  * @return 0 on success, non-zero on error
 546  */
 547
 548 static int
 549 dview_pclose (FBUF *fs)
 550 {
 551     int rv = -1;
 552
 553     if (fs != NULL)
 554     {
 555         rv = pclose (fs->data);
 556         dview_ffree (fs);
 557     }
 558
 559     return rv;
 560 }
 561
 562 /* --------------------------------------------------------------------------------------------- */
 563
 564 /**
 565  * Get one char (byte) from string
 566  *
 567  * @param str ...
 568  * @param ch ...
 569  * @return TRUE on success, FALSE otherwise
 570  */
 571
 572 static gboolean
 573 dview_get_byte (const char *str, int *ch)
 574 {
 575     if (str == NULL)
 576         return FALSE;
 577
 578     *ch = (unsigned char) (*str);
 579     return TRUE;
 580 }
 581
 582 /* --------------------------------------------------------------------------------------------- */
 583
 584 #ifdef HAVE_CHARSET
 585 /**
 586  * Get utf multibyte char from string
 587  *
 588  * @param str ...
 589  * @param ch ...
 590  * @param ch_length ...
 591  * @return TRUE on success, FALSE otherwise
 592  */
 593
 594 static gboolean
 595 dview_get_utf (const char *str, int *ch, int *ch_length)
 596 {
 597     if (str == NULL)
 598         return FALSE;
 599
 600     *ch = g_utf8_get_char_validated (str, -1);
 601
 602     if (*ch < 0)
 603     {
 604         *ch = (unsigned char) (*str);
 605         *ch_length = 1;
 606     }
 607     else
 608     {
 609         const char *next_ch;
 610
 611         // Calculate UTF-8 char length
 612         next_ch = g_utf8_next_char (str);
 613         *ch_length = next_ch - str;
 614     }
 615
 616     return TRUE;
 617 }
 618
 619 /* --------------------------------------------------------------------------------------------- */
 620
 621 static int
 622 dview_str_utf8_offset_to_pos (const char *text, size_t length)
 623 {
 624     ptrdiff_t result;
 625
 626     if (text == NULL || text[0] == '\0')
 627         return length;
 628
 629     if (g_utf8_validate (text, -1, NULL))
 630         result = g_utf8_offset_to_pointer (text, length) - text;
 631     else
 632     {
 633         gunichar uni;
 634         char *tmpbuf, *buffer;
 635
 636         buffer = tmpbuf = g_strdup (text);
 637         while (tmpbuf[0] != '\0')
 638         {
 639             uni = g_utf8_get_char_validated (tmpbuf, -1);
 640             if ((uni != (gunichar) (-1)) && (uni != (gunichar) (-2)))
 641                 tmpbuf = g_utf8_next_char (tmpbuf);
 642             else
 643             {
 644                 tmpbuf[0] = '.';
 645                 tmpbuf++;
 646             }
 647         }
 648         result = g_utf8_offset_to_pointer (tmpbuf, length) - tmpbuf;
 649         g_free (buffer);
 650     }
 651     return MAX (length, (size_t) result);
 652 }
 653 #endif
 654
 655 /* --------------------------------------------------------------------------------------------- */
 656
 657 /* diff parse *************************************************************** */
 658
 659 /**
 660  * Read decimal number from string.
 661  *
 662  * @param[in,out] str string to parse
 663  * @param[out] n extracted number
 664  * @return 0 if success, otherwise non-zero
 665  */
 666
 667 static int
 668 scan_deci (const char **str, int *n)
 669 {
 670     const char *p = *str;
 671     char *q;
 672
 673     errno = 0;
 674     *n = strtol (p, &q, 10);
 675     if (errno != 0 || p == q)
 676         return -1;
 677     *str = q;
 678     return 0;
 679 }
 680
 681 /* --------------------------------------------------------------------------------------------- */
 682
 683 /**
 684  * Parse line for diff statement.
 685  *
 686  * @param p string to parse
 687  * @param ops list of diff statements
 688  * @return 0 if success, otherwise non-zero
 689  */
 690
 691 static int
 692 scan_line (const char *p, GArray *ops)
 693 {
 694     DIFFCMD op;
 695
 696     int f1, f2;
 697     int t1, t2;
 698     int cmd;
 699     gboolean range = FALSE;
 700
 701     /* handle the following cases:
 702      *  NUMaNUM[,NUM]
 703      *  NUM[,NUM]cNUM[,NUM]
 704      *  NUM[,NUM]dNUM
 705      * where NUM is a positive integer
 706      */
 707
 708     if (scan_deci (&p, &f1) != 0 || f1 < 0)
 709         return -1;
 710
 711     f2 = f1;
 712     if (*p == ',')
 713     {
 714         p++;
 715         if (scan_deci (&p, &f2) != 0 || f2 < f1)
 716             return -1;
 717
 718         range = TRUE;
 719     }
 720
 721     cmd = *p++;
 722     if (cmd == 'a')
 723     {
 724         if (range)
 725             return -1;
 726     }
 727     else if (cmd != 'c' && cmd != 'd')
 728         return -1;
 729
 730     if (scan_deci (&p, &t1) != 0 || t1 < 0)
 731         return -1;
 732
 733     t2 = t1;
 734     range = FALSE;
 735     if (*p == ',')
 736     {
 737         p++;
 738         if (scan_deci (&p, &t2) != 0 || t2 < t1)
 739             return -1;
 740
 741         range = TRUE;
 742     }
 743
 744     if (cmd == 'd' && range)
 745         return -1;
 746
 747     op.a[0][0] = f1;
 748     op.a[0][1] = f2;
 749     op.cmd = cmd;
 750     op.a[1][0] = t1;
 751     op.a[1][1] = t2;
 752     g_array_append_val (ops, op);
 753     return 0;
 754 }
 755
 756 /* --------------------------------------------------------------------------------------------- */
 757
 758 /**
 759  * Parse diff output and extract diff statements.
 760  *
 761  * @param f stream to read from
 762  * @param ops list of diff statements to fill
 763  * @return positive number indicating number of hunks, otherwise negative
 764  */
 765
 766 static int
 767 scan_diff (FBUF *f, GArray *ops)
 768 {
 769     int sz;
 770     char buf[BUFSIZ];
 771
 772     while ((sz = dview_fgets (buf, sizeof (buf) - 1, f)) != 0)
 773     {
 774         if (isdigit (buf[0]))
 775         {
 776             if (buf[sz - 1] != '\n')
 777                 return -1;
 778
 779             buf[sz] = '\0';
 780             if (scan_line (buf, ops) != 0)
 781                 return -1;
 782         }
 783         else
 784             while (buf[sz - 1] != '\n' && (sz = dview_fgets (buf, sizeof (buf), f)) != 0)
 785                 ;
 786     }
 787
 788     return ops->len;
 789 }
 790
 791 /* --------------------------------------------------------------------------------------------- */
 792
 793 /**
 794  * Invoke diff and extract diff statements.
 795  *
 796  * @param args extra arguments to be passed to diff
 797  * @param extra more arguments to be passed to diff
 798  * @param file1 first file to compare
 799  * @param file2 second file to compare
 800  * @param ops list of diff statements to fill
 801  *
 802  * @return positive number indicating number of hunks, otherwise negative
 803  */
 804
 805 static int
 806 dff_execute (const char *args, const char *extra, const char *file1, const char *file2, GArray *ops)
 807 {
 808     static const char *opt = " --old-group-format='%df%(f=l?:,%dl)d%dE\n'"
 809                              " --new-group-format='%dea%dF%(F=L?:,%dL)\n'"
 810                              " --changed-group-format='%df%(f=l?:,%dl)c%dF%(F=L?:,%dL)\n'"
 811                              " --unchanged-group-format=''";
 812
 813     int rv;
 814     FBUF *f;
 815     char *cmd;
 816     int code;
 817     char *file1_esc, *file2_esc;
 818
 819     // escape potential $ to avoid shell variable substitutions in popen()
 820     file1_esc = str_shell_escape (file1);
 821     file2_esc = str_shell_escape (file2);
 822     cmd = g_strdup_printf ("diff %s %s %s %s %s", args, extra, opt, file1_esc, file2_esc);
 823     g_free (file1_esc);
 824     g_free (file2_esc);
 825
 826     if (cmd == NULL)
 827         return -1;
 828
 829     f = dview_popen (cmd, O_RDONLY);
 830     g_free (cmd);
 831
 832     if (f == NULL)
 833         return -1;
 834
 835     rv = scan_diff (f, ops);
 836     code = dview_pclose (f);
 837
 838     if (rv < 0 || code == -1 || !WIFEXITED (code) || WEXITSTATUS (code) == 2)
 839         rv = -1;
 840
 841     return rv;
 842 }
 843
 844 /* --------------------------------------------------------------------------------------------- */
 845
 846 static gboolean
 847 printer_for (char ch, DFUNC printer, void *ctx, FBUF *f, int *line, off_t *off)
 848 {
 849     size_t sz;
 850     char buf[BUFSIZ];
 851
 852     sz = dview_fgets (buf, sizeof (buf), f);
 853     if (sz == 0)
 854         return FALSE;
 855
 856     (*line)++;
 857     printer (ctx, ch, *line, *off, sz, buf);
 858     *off += sz;
 859
 860     while (buf[sz - 1] != '\n')
 861     {
 862         sz = dview_fgets (buf, sizeof (buf), f);
 863         if (sz == 0)
 864         {
 865             printer (ctx, 0, 0, 0, 1, "\n");
 866             break;
 867         }
 868
 869         printer (ctx, 0, 0, 0, sz, buf);
 870         *off += sz;
 871     }
 872
 873     return TRUE;
 874 }
 875
 876 /* --------------------------------------------------------------------------------------------- */
 877
 878 /**
 879  * Reparse and display file according to diff statements.
 880  *
 881  * @param ord DIFF_LEFT if 1st file is displayed , DIFF_RIGHT if 2nd file is displayed.
 882  * @param filename file name to display
 883  * @param ops list of diff statements
 884  * @param printer printf-like function to be used for displaying
 885  * @param ctx printer context
 886  *
 887  * @return 0 if success, otherwise non-zero
 888  */
 889
 890 static int
 891 dff_reparse (diff_place_t ord, const char *filename, const GArray *ops, DFUNC printer, void *ctx)
 892 {
 893     size_t i;
 894     FBUF *f;
 895     int line = 0;
 896     off_t off = 0;
 897     const DIFFCMD *op;
 898     diff_place_t eff;
 899     int add_cmd, del_cmd;
 900
 901     f = dview_fopen (filename, O_RDONLY);
 902     if (f == NULL)
 903         return -1;
 904
 905     if (ord != DIFF_LEFT)
 906         ord = DIFF_RIGHT;
 907     eff = ord;
 908
 909     if (ord != DIFF_LEFT)
 910     {
 911         add_cmd = 'd';
 912         del_cmd = 'a';
 913     }
 914     else
 915     {
 916         add_cmd = 'a';
 917         del_cmd = 'd';
 918     }
 919 #define F1 a[eff][0]
 920 #define F2 a[eff][1]
 921 #define T1 a[ord ^ 1][0]
 922 #define T2 a[ord ^ 1][1]
 923     for (i = 0; i < ops->len; i++)
 924     {
 925         int n;
 926
 927         op = &g_array_index (ops, DIFFCMD, i);
 928
 929         n = op->F1;
 930         if (op->cmd != add_cmd)
 931             n--;
 932
 933         while (line < n && printer_for (EQU_CH, printer, ctx, f, &line, &off))
 934             ;
 935
 936         if (line != n)
 937             goto err;
 938
 939         if (op->cmd == add_cmd)
 940             for (n = op->T2 - op->T1 + 1; n != 0; n--)
 941                 printer (ctx, DEL_CH, 0, 0, 1, "\n");
 942
 943         if (op->cmd == del_cmd)
 944         {
 945             for (n = op->F2 - op->F1 + 1;
 946                  n != 0 && printer_for (ADD_CH, printer, ctx, f, &line, &off); n--)
 947                 ;
 948
 949             if (n != 0)
 950                 goto err;
 951         }
 952
 953         if (op->cmd == 'c')
 954         {
 955             for (n = op->F2 - op->F1 + 1;
 956                  n != 0 && printer_for (CHG_CH, printer, ctx, f, &line, &off); n--)
 957                 ;
 958
 959             if (n != 0)
 960                 goto err;
 961
 962             for (n = op->T2 - op->T1 - (op->F2 - op->F1); n > 0; n--)
 963                 printer (ctx, CHG_CH, 0, 0, 1, "\n");
 964         }
 965     }
 966 #undef T2
 967 #undef T1
 968 #undef F2
 969 #undef F1
 970
 971     while (printer_for (EQU_CH, printer, ctx, f, &line, &off))
 972         ;
 973
 974     dview_fclose (f);
 975     return 0;
 976
 977 err:
 978     dview_fclose (f);
 979     return -1;
 980 }
 981
 982 /* --------------------------------------------------------------------------------------------- */
 983
 984 /* horizontal diff ********************************************************** */
 985
 986 /**
 987  * Longest common substring.
 988  *
 989  * @param s first string
 990  * @param m length of first string
 991  * @param t second string
 992  * @param n length of second string
 993  * @param ret list of offsets for longest common substrings inside each string
 994  * @param min minimum length of common substrings
 995  *
 996  * @return 0 if success, nonzero otherwise
 997  */
 998
 999 static int
1000 lcsubstr (const char *s, int m, const char *t, int n, GArray *ret, int min)
1001 {
1002     int i, j;
1003     int *Lprev, *Lcurr;
1004     int z = 0;
1005
1006     if (m < min || n < min)
1007     {
1008         // XXX early culling
1009         return 0;
1010     }
1011
1012     Lprev = g_try_new0 (int, n + 1);
1013     if (Lprev == NULL)
1014         return -1;
1015
1016     Lcurr = g_try_new0 (int, n + 1);
1017     if (Lcurr == NULL)
1018     {
1019         g_free (Lprev);
1020         return -1;
1021     }
1022
1023     for (i = 0; i < m; i++)
1024     {
1025         int *L;
1026
1027         L = Lprev;
1028         Lprev = Lcurr;
1029         Lcurr = L;
1030 #ifdef USE_MEMSET_IN_LCS
1031         memset (Lcurr, 0, (n + 1) * sizeof (*Lcurr));
1032 #endif
1033         for (j = 0; j < n; j++)
1034         {
1035 #ifndef USE_MEMSET_IN_LCS
1036             Lcurr[j + 1] = 0;
1037 #endif
1038             if (s[i] == t[j])
1039             {
1040                 int v;
1041
1042                 v = Lprev[j] + 1;
1043                 Lcurr[j + 1] = v;
1044                 if (z < v)
1045                 {
1046                     z = v;
1047                     g_array_set_size (ret, 0);
1048                 }
1049                 if (z == v && z >= min)
1050                 {
1051                     int off0, off1;
1052                     size_t k;
1053
1054                     off0 = i - z + 1;
1055                     off1 = j - z + 1;
1056
1057                     for (k = 0; k < ret->len; k++)
1058                     {
1059                         PAIR *p = (PAIR *) g_array_index (ret, PAIR, k);
1060                         if ((*p)[0] == off0 || (*p)[1] >= off1)
1061                             break;
1062                     }
1063                     if (k == ret->len)
1064                     {
1065                         PAIR p2;
1066
1067                         p2[0] = off0;
1068                         p2[1] = off1;
1069                         g_array_append_val (ret, p2);
1070                     }
1071                 }
1072             }
1073         }
1074     }
1075
1076     g_free (Lcurr);
1077     g_free (Lprev);
1078     return z;
1079 }
1080
1081 /* --------------------------------------------------------------------------------------------- */
1082
1083 /**
1084  * Scan recursively for common substrings and build ranges.
1085  *
1086  * @param s first string
1087  * @param t second string
1088  * @param bracket current limits for both of the strings
1089  * @param min minimum length of common substrings
1090  * @param hdiff list of horizontal diff ranges to fill
1091  * @param depth recursion depth
1092  *
1093  * @return 0 if success, nonzero otherwise
1094  */
1095
1096 static gboolean
1097 hdiff_multi (const char *s, const char *t, const BRACKET bracket, int min, GArray *hdiff,
1098              unsigned int depth)
1099 {
1100     BRACKET p;
1101
1102     if (depth-- != 0)
1103     {
1104         GArray *ret;
1105         BRACKET b;
1106         int len;
1107
1108         ret = g_array_new (FALSE, TRUE, sizeof (PAIR));
1109
1110         len = lcsubstr (s + bracket[DIFF_LEFT].off, bracket[DIFF_LEFT].len,
1111                         t + bracket[DIFF_RIGHT].off, bracket[DIFF_RIGHT].len, ret, min);
1112         if (ret->len != 0)
1113         {
1114             size_t k = 0;
1115             const PAIR *data = (const PAIR *) &g_array_index (ret, PAIR, 0);
1116             const PAIR *data2;
1117
1118             b[DIFF_LEFT].off = bracket[DIFF_LEFT].off;
1119             b[DIFF_LEFT].len = (*data)[0];
1120             b[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off;
1121             b[DIFF_RIGHT].len = (*data)[1];
1122             if (!hdiff_multi (s, t, b, min, hdiff, depth))
1123                 return FALSE;
1124
1125             for (k = 0; k < ret->len - 1; k++)
1126             {
1127                 data = (const PAIR *) &g_array_index (ret, PAIR, k);
1128                 data2 = (const PAIR *) &g_array_index (ret, PAIR, k + 1);
1129                 b[DIFF_LEFT].off = bracket[DIFF_LEFT].off + (*data)[0] + len;
1130                 b[DIFF_LEFT].len = (*data2)[0] - (*data)[0] - len;
1131                 b[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off + (*data)[1] + len;
1132                 b[DIFF_RIGHT].len = (*data2)[1] - (*data)[1] - len;
1133                 if (!hdiff_multi (s, t, b, min, hdiff, depth))
1134                     return FALSE;
1135             }
1136             data = (const PAIR *) &g_array_index (ret, PAIR, k);
1137             b[DIFF_LEFT].off = bracket[DIFF_LEFT].off + (*data)[0] + len;
1138             b[DIFF_LEFT].len = bracket[DIFF_LEFT].len - (*data)[0] - len;
1139             b[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off + (*data)[1] + len;
1140             b[DIFF_RIGHT].len = bracket[DIFF_RIGHT].len - (*data)[1] - len;
1141             if (!hdiff_multi (s, t, b, min, hdiff, depth))
1142                 return FALSE;
1143
1144             g_array_free (ret, TRUE);
1145             return TRUE;
1146         }
1147     }
1148
1149     p[DIFF_LEFT].off = bracket[DIFF_LEFT].off;
1150     p[DIFF_LEFT].len = bracket[DIFF_LEFT].len;
1151     p[DIFF_RIGHT].off = bracket[DIFF_RIGHT].off;
1152     p[DIFF_RIGHT].len = bracket[DIFF_RIGHT].len;
1153     g_array_append_val (hdiff, p);
1154
1155     return TRUE;
1156 }
1157
1158 /* --------------------------------------------------------------------------------------------- */
1159
1160 /**
1161  * Build list of horizontal diff ranges.
1162  *
1163  * @param s first string
1164  * @param m length of first string
1165  * @param t second string
1166  * @param n length of second string
1167  * @param min minimum length of common substrings
1168  * @param hdiff list of horizontal diff ranges to fill
1169  * @param depth recursion depth
1170  *
1171  * @return 0 if success, nonzero otherwise
1172  */
1173
1174 static gboolean
1175 hdiff_scan (const char *s, int m, const char *t, int n, int min, GArray *hdiff, unsigned int depth)
1176 {
1177     int i;
1178     BRACKET b;
1179
1180     // dumbscan (single horizontal diff) -- does not compress whitespace
1181     for (i = 0; i < m && i < n && s[i] == t[i]; i++)
1182         ;
1183     for (; m > i && n > i && s[m - 1] == t[n - 1]; m--, n--)
1184         ;
1185
1186     b[DIFF_LEFT].off = i;
1187     b[DIFF_LEFT].len = m - i;
1188     b[DIFF_RIGHT].off = i;
1189     b[DIFF_RIGHT].len = n - i;
1190
1191     // smartscan (multiple horizontal diff)
1192     return hdiff_multi (s, t, b, min, hdiff, depth);
1193 }
1194
1195 /* --------------------------------------------------------------------------------------------- */
1196
1197 /* read line **************************************************************** */
1198
1199 /**
1200  * Check if character is inside horizontal diff limits.
1201  *
1202  * @param k rank of character inside line
1203  * @param hdiff horizontal diff structure
1204  * @param ord DIFF_LEFT if reading from first file, DIFF_RIGHT if reading from 2nd file
1205  *
1206  * @return TRUE if inside hdiff limits, FALSE otherwise
1207  */
1208
1209 static gboolean
1210 is_inside (int k, GArray *hdiff, diff_place_t ord)
1211 {
1212     size_t i;
1213     BRACKET *b;
1214
1215     for (i = 0; i < hdiff->len; i++)
1216     {
1217         int start, end;
1218
1219         b = &g_array_index (hdiff, BRACKET, i);
1220         start = (*b)[ord].off;
1221         end = start + (*b)[ord].len;
1222         if (k >= start && k < end)
1223             return TRUE;
1224     }
1225     return FALSE;
1226 }
1227
1228 /* --------------------------------------------------------------------------------------------- */
1229
1230 /**
1231  * Copy 'src' to 'dst' expanding tabs.
1232  * @note The procedure returns when all bytes are consumed from 'src'
1233  *
1234  * @param dst destination buffer
1235  * @param src source buffer
1236  * @param srcsize size of src buffer
1237  * @param base virtual base of this string, needed to calculate tabs
1238  * @param ts tab size
1239  *
1240  * @return new virtual base
1241  */
1242
1243 static int
1244 cvt_cpy (char *dst, const char *src, size_t srcsize, int base, int ts)
1245 {
1246     int i;
1247
1248     for (i = 0; srcsize != 0; i++, src++, dst++, srcsize--)
1249     {
1250         *dst = *src;
1251         if (*src == '\t')
1252         {
1253             int j;
1254
1255             j = TAB_SKIP (ts, i + base);
1256             i += j - 1;
1257             fill_by_space (dst, j, FALSE);
1258             dst += j - 1;
1259         }
1260     }
1261     return i + base;
1262 }
1263
1264 /* --------------------------------------------------------------------------------------------- */
1265
1266 /**
1267  * Copy 'src' to 'dst' expanding tabs.
1268  *
1269  * @param dst destination buffer
1270  * @param dstsize size of dst buffer
1271  * @param[in,out] _src source buffer
1272  * @param srcsize size of src buffer
1273  * @param base virtual base of this string, needed to calculate tabs
1274  * @param ts tab size
1275  *
1276  * @return new virtual base
1277  *
1278  * @note The procedure returns when all bytes are consumed from 'src'
1279  *       or 'dstsize' bytes are written to 'dst'
1280  * @note Upon return, 'src' points to the first unwritten character in source
1281  */
1282
1283 static int
1284 cvt_ncpy (char *dst, int dstsize, const char **_src, size_t srcsize, int base, int ts)
1285 {
1286     int i;
1287     const char *src = *_src;
1288
1289     for (i = 0; i < dstsize && srcsize != 0; i++, src++, dst++, srcsize--)
1290     {
1291         *dst = *src;
1292         if (*src == '\t')
1293         {
1294             int j;
1295
1296             j = TAB_SKIP (ts, i + base);
1297             if (j > dstsize - i)
1298                 j = dstsize - i;
1299             i += j - 1;
1300             fill_by_space (dst, j, FALSE);
1301             dst += j - 1;
1302         }
1303     }
1304     *_src = src;
1305     return i + base;
1306 }
1307
1308 /* --------------------------------------------------------------------------------------------- */
1309
1310 /**
1311  * Read line from memory, converting tabs to spaces and padding with spaces.
1312  *
1313  * @param src buffer to read from
1314  * @param srcsize size of src buffer
1315  * @param dst buffer to read to
1316  * @param dstsize size of dst buffer, excluding trailing null
1317  * @param skip number of characters to skip
1318  * @param ts tab size
1319  * @param show_cr show trailing carriage return as ^M
1320  *
1321  * @return negative on error, otherwise number of bytes except padding
1322  */
1323
1324 static int
1325 cvt_mget (const char *src, size_t srcsize, char *dst, int dstsize, int skip, int ts,
1326           gboolean show_cr)
1327 {
1328     int sz = 0;
1329
1330     if (src != NULL)
1331     {
1332         int i;
1333         char *tmp = dst;
1334         const int base = 0;
1335
1336         for (i = 0; dstsize != 0 && srcsize != 0 && *src != '\n'; i++, src++, srcsize--)
1337         {
1338             if (*src == '\t')
1339             {
1340                 int j;
1341
1342                 j = TAB_SKIP (ts, i + base);
1343                 i += j - 1;
1344                 while (j-- > 0)
1345                 {
1346                     if (skip > 0)
1347                         skip--;
1348                     else if (dstsize != 0)
1349                     {
1350                         dstsize--;
1351                         *dst++ = ' ';
1352                     }
1353                 }
1354             }
1355             else if (src[0] == '\r' && (srcsize == 1 || src[1] == '\n'))
1356             {
1357                 if (skip == 0 && show_cr)
1358                 {
1359                     if (dstsize > 1)
1360                     {
1361                         dstsize -= 2;
1362                         *dst++ = '^';
1363                         *dst++ = 'M';
1364                     }
1365                     else
1366                     {
1367                         dstsize--;
1368                         *dst++ = '.';
1369                     }
1370                 }
1371                 break;
1372             }
1373             else if (skip > 0)
1374             {
1375 #ifdef HAVE_CHARSET
1376                 int ch = 0;
1377                 int ch_length = 1;
1378
1379                 (void) dview_get_utf (src, &ch, &ch_length);
1380
1381                 if (ch_length > 1)
1382                     skip += ch_length - 1;
1383 #endif
1384
1385                 skip--;
1386             }
1387             else
1388             {
1389                 dstsize--;
1390                 *dst++ = *src;
1391             }
1392         }
1393         sz = dst - tmp;
1394     }
1395
1396     fill_by_space (dst, dstsize, TRUE);
1397
1398     return sz;
1399 }
1400
1401 /* --------------------------------------------------------------------------------------------- */
1402
1403 /**
1404  * Read line from memory and build attribute array.
1405  *
1406  * @param src buffer to read from
1407  * @param srcsize size of src buffer
1408  * @param dst buffer to read to
1409  * @param dstsize size of dst buffer, excluding trailing null
1410  * @param skip number of characters to skip
1411  * @param ts tab size
1412  * @param show_cr show trailing carriage return as ^M
1413  * @param hdiff horizontal diff structure
1414  * @param ord DIFF_LEFT if reading from first file, DIFF_RIGHT if reading from 2nd file
1415  * @param att buffer of attributes
1416  *
1417  * @return negative on error, otherwise number of bytes except padding
1418  */
1419
1420 static int
1421 cvt_mgeta (const char *src, size_t srcsize, char *dst, int dstsize, int skip, int ts,
1422            gboolean show_cr, GArray *hdiff, diff_place_t ord, char *att)
1423 {
1424     int sz = 0;
1425
1426     if (src != NULL)
1427     {
1428         int i, k;
1429         char *tmp = dst;
1430         const int base = 0;
1431
1432         for (i = 0, k = 0; dstsize != 0 && srcsize != 0 && *src != '\n'; i++, k++, src++, srcsize--)
1433         {
1434             if (*src == '\t')
1435             {
1436                 int j;
1437
1438                 j = TAB_SKIP (ts, i + base);
1439                 i += j - 1;
1440                 while (j-- > 0)
1441                 {
1442                     if (skip != 0)
1443                         skip--;
1444                     else if (dstsize != 0)
1445                     {
1446                         dstsize--;
1447                         *att++ = is_inside (k, hdiff, ord);
1448                         *dst++ = ' ';
1449                     }
1450                 }
1451             }
1452             else if (src[0] == '\r' && (srcsize == 1 || src[1] == '\n'))
1453             {
1454                 if (skip == 0 && show_cr)
1455                 {
1456                     if (dstsize > 1)
1457                     {
1458                         dstsize -= 2;
1459                         *att++ = is_inside (k, hdiff, ord);
1460                         *dst++ = '^';
1461                         *att++ = is_inside (k, hdiff, ord);
1462                         *dst++ = 'M';
1463                     }
1464                     else
1465                     {
1466                         dstsize--;
1467                         *att++ = is_inside (k, hdiff, ord);
1468                         *dst++ = '.';
1469                     }
1470                 }
1471                 break;
1472             }
1473             else if (skip != 0)
1474             {
1475 #ifdef HAVE_CHARSET
1476                 int ch = 0;
1477                 int ch_length = 1;
1478
1479                 (void) dview_get_utf (src, &ch, &ch_length);
1480                 if (ch_length > 1)
1481                     skip += ch_length - 1;
1482 #endif
1483
1484                 skip--;
1485             }
1486             else
1487             {
1488                 dstsize--;
1489                 *att++ = is_inside (k, hdiff, ord);
1490                 *dst++ = *src;
1491             }
1492         }
1493         sz = dst - tmp;
1494     }
1495
1496     memset (att, '\0', dstsize);
1497     fill_by_space (dst, dstsize, TRUE);
1498
1499     return sz;
1500 }
1501
1502 /* --------------------------------------------------------------------------------------------- */
1503
1504 /**
1505  * Read line from file, converting tabs to spaces and padding with spaces.
1506  *
1507  * @param f file stream to read from
1508  * @param off offset of line inside file
1509  * @param dst buffer to read to
1510  * @param dstsize size of dst buffer, excluding trailing null
1511  * @param skip number of characters to skip
1512  * @param ts tab size
1513  * @param show_cr show trailing carriage return as ^M
1514  *
1515  * @return negative on error, otherwise number of bytes except padding
1516  */
1517
1518 static int
1519 cvt_fget (FBUF *f, off_t off, char *dst, size_t dstsize, int skip, int ts, gboolean show_cr)
1520 {
1521     int base = 0;
1522     int old_base = base;
1523     size_t amount = dstsize;
1524     size_t useful, offset;
1525     size_t i;
1526     size_t sz;
1527     int lastch = '\0';
1528     const char *q = NULL;
1529     char tmp[BUFSIZ];  // XXX capacity must be >= MAX{dstsize + 1, amount}
1530     char cvt[BUFSIZ];  // XXX capacity must be >= MAX_TAB_WIDTH * amount
1531
1532     if (sizeof (tmp) < amount || sizeof (tmp) <= dstsize || sizeof (cvt) < 8 * amount)
1533     {
1534         // abnormal, but avoid buffer overflow
1535         fill_by_space (dst, dstsize, TRUE);
1536         return 0;
1537     }
1538
1539     dview_fseek (f, off, SEEK_SET);
1540
1541     while (skip > base)
1542     {
1543         old_base = base;
1544         sz = dview_fgets (tmp, amount, f);
1545         if (sz == 0)
1546             break;
1547
1548         base = cvt_cpy (cvt, tmp, sz, old_base, ts);
1549         if (cvt[base - old_base - 1] == '\n')
1550         {
1551             q = &cvt[base - old_base - 1];
1552             base = old_base + q - cvt + 1;
1553             break;
1554         }
1555     }
1556
1557     if (base < skip)
1558     {
1559         fill_by_space (dst, dstsize, TRUE);
1560         return 0;
1561     }
1562
1563     useful = base - skip;
1564     offset = skip - old_base;
1565
1566     if (useful <= dstsize)
1567     {
1568         if (useful != 0)
1569             memmove (dst, cvt + offset, useful);
1570
1571         if (q == NULL)
1572         {
1573             sz = dview_fgets (tmp, dstsize - useful + 1, f);
1574             if (sz != 0)
1575             {
1576                 const char *ptr = tmp;
1577
1578                 useful += cvt_ncpy (dst + useful, dstsize - useful, &ptr, sz, base, ts) - base;
1579                 if (ptr < tmp + sz)
1580                     lastch = *ptr;
1581             }
1582         }
1583         sz = useful;
1584     }
1585     else
1586     {
1587         memmove (dst, cvt + offset, dstsize);
1588         sz = dstsize;
1589         lastch = cvt[offset + dstsize];
1590     }
1591
1592     dst[sz] = lastch;
1593     for (i = 0; i < sz && dst[i] != '\n'; i++)
1594         if (dst[i] == '\r' && dst[i + 1] == '\n')
1595         {
1596             if (show_cr)
1597             {
1598                 if (i + 1 < dstsize)
1599                 {
1600                     dst[i++] = '^';
1601                     dst[i++] = 'M';
1602                 }
1603                 else
1604                     dst[i++] = '*';
1605             }
1606             break;
1607         }
1608
1609     fill_by_space (dst, dstsize, TRUE);
1610
1611     return sz;
1612 }
1613
1614 /* --------------------------------------------------------------------------------------------- */
1615 /* diff printers et al ****************************************************** */
1616
1617 static void
1618 cc_free_elt (gpointer elt)
1619 {
1620     DIFFLN *p = (DIFFLN *) elt;
1621
1622     if (p != NULL)
1623         g_free (p->p);
1624 }
1625
1626 /* --------------------------------------------------------------------------------------------- */
1627
1628 static int
1629 printer (void *ctx, int ch, int line, off_t off, size_t sz, const char *str)
1630 {
1631     GArray *a = ((PRINTER_CTX *) ctx)->a;
1632     DSRC dsrc = ((PRINTER_CTX *) ctx)->dsrc;
1633
1634     if (ch != 0)
1635     {
1636         DIFFLN p;
1637
1638         p.p = NULL;
1639         p.ch = ch;
1640         p.line = line;
1641         p.u.off = off;
1642         if (dsrc == DATA_SRC_MEM && line != 0)
1643         {
1644             if (sz != 0 && str[sz - 1] == '\n')
1645                 sz--;
1646             if (sz > 0)
1647                 p.p = g_strndup (str, sz);
1648             p.u.len = sz;
1649         }
1650         g_array_append_val (a, p);
1651     }
1652     else if (dsrc == DATA_SRC_MEM)
1653     {
1654         DIFFLN *p;
1655
1656         p = &g_array_index (a, DIFFLN, a->len - 1);
1657         if (sz != 0 && str[sz - 1] == '\n')
1658             sz--;
1659         if (sz != 0)
1660         {
1661             size_t new_size;
1662             char *q;
1663
1664             new_size = p->u.len + sz;
1665             q = g_realloc (p->p, new_size);
1666             memcpy (q + p->u.len, str, sz);
1667             p->p = q;
1668         }
1669         p->u.len += sz;
1670     }
1671     if (dsrc == DATA_SRC_TMP && (line != 0 || ch == 0))
1672     {
1673         FBUF *f = ((PRINTER_CTX *) ctx)->f;
1674         dview_fwrite (f, str, sz);
1675     }
1676     return 0;
1677 }
1678
1679 /* --------------------------------------------------------------------------------------------- */
1680
1681 static int
1682 redo_diff (WDiff *dview)
1683 {
1684     FBUF *const *f = dview->f;
1685     PRINTER_CTX ctx;
1686     GArray *ops;
1687     int ndiff;
1688     int rv = 0;
1689     char extra[BUF_MEDIUM];
1690
1691     extra[0] = '\0';
1692     if (dview->opt.quality == 2)
1693         strcat (extra, " -d");
1694     if (dview->opt.quality == 1)
1695         strcat (extra, " --speed-large-files");
1696     if (dview->opt.strip_trailing_cr)
1697         strcat (extra, " --strip-trailing-cr");
1698     if (dview->opt.ignore_tab_expansion)
1699         strcat (extra, " -E");
1700     if (dview->opt.ignore_space_change)
1701         strcat (extra, " -b");
1702     if (dview->opt.ignore_all_space)
1703         strcat (extra, " -w");
1704     if (dview->opt.ignore_case)
1705         strcat (extra, " -i");
1706
1707     if (dview->dsrc != DATA_SRC_MEM)
1708     {
1709         dview_freset (f[DIFF_LEFT]);
1710         dview_freset (f[DIFF_RIGHT]);
1711     }
1712
1713     ops = g_array_new (FALSE, FALSE, sizeof (DIFFCMD));
1714     ndiff = dff_execute (dview->args, extra, dview->file[DIFF_LEFT], dview->file[DIFF_RIGHT], ops);
1715     if (ndiff < 0)
1716     {
1717         if (ops != NULL)
1718             g_array_free (ops, TRUE);
1719         return -1;
1720     }
1721
1722     ctx.dsrc = dview->dsrc;
1723     ctx.a = dview->a[DIFF_LEFT];
1724     ctx.f = f[DIFF_LEFT];
1725     rv |= dff_reparse (DIFF_LEFT, dview->file[DIFF_LEFT], ops, printer, &ctx);
1726
1727     ctx.a = dview->a[DIFF_RIGHT];
1728     ctx.f = f[DIFF_RIGHT];
1729     rv |= dff_reparse (DIFF_RIGHT, dview->file[DIFF_RIGHT], ops, printer, &ctx);
1730
1731     if (ops != NULL)
1732         g_array_free (ops, TRUE);
1733
1734     if (rv != 0 || dview->a[DIFF_LEFT]->len != dview->a[DIFF_RIGHT]->len)
1735         return -1;
1736
1737     if (dview->dsrc == DATA_SRC_TMP)
1738     {
1739         dview_ftrunc (f[DIFF_LEFT]);
1740         dview_ftrunc (f[DIFF_RIGHT]);
1741     }
1742
1743     if (dview->dsrc == DATA_SRC_MEM && HDIFF_ENABLE)
1744     {
1745         size_t i;
1746
1747         dview->hdiff = g_ptr_array_new ();
1748
1749         for (i = 0; i < dview->a[DIFF_LEFT]->len; i++)
1750         {
1751             GArray *h = NULL;
1752             const DIFFLN *p;
1753             const DIFFLN *q;
1754
1755             p = &g_array_index (dview->a[DIFF_LEFT], DIFFLN, i);
1756             q = &g_array_index (dview->a[DIFF_RIGHT], DIFFLN, i);
1757             if (p->line != 0 && q->line != 0 && p->ch == CHG_CH)
1758             {
1759                 gboolean runresult;
1760
1761                 h = g_array_new (FALSE, FALSE, sizeof (BRACKET));
1762
1763                 runresult =
1764                     hdiff_scan (p->p, p->u.len, q->p, q->u.len, HDIFF_MINCTX, h, HDIFF_DEPTH);
1765                 if (!runresult)
1766                 {
1767                     g_array_free (h, TRUE);
1768                     h = NULL;
1769                 }
1770             }
1771
1772             g_ptr_array_add (dview->hdiff, h);
1773         }
1774     }
1775     return ndiff;
1776 }
1777
1778 /* --------------------------------------------------------------------------------------------- */
1779
1780 static void
1781 destroy_hdiff (WDiff *dview)
1782 {
1783     if (dview->hdiff != NULL)
1784     {
1785         int i;
1786         int len;
1787
1788         len = dview->a[DIFF_LEFT]->len;
1789
1790         for (i = 0; i < len; i++)
1791         {
1792             GArray *h;
1793
1794             h = (GArray *) g_ptr_array_index (dview->hdiff, i);
1795             if (h != NULL)
1796                 g_array_free (h, TRUE);
1797         }
1798         g_ptr_array_free (dview->hdiff, TRUE);
1799         dview->hdiff = NULL;
1800     }
1801
1802     mc_search_free (dview->search.handle);
1803     dview->search.handle = NULL;
1804     MC_PTR_FREE (dview->search.last_string);
1805 }
1806
1807 /* --------------------------------------------------------------------------------------------- */
1808 /* stuff ******************************************************************** */
1809
1810 static int
1811 get_digits (unsigned int n)
1812 {
1813     int d = 1;
1814
1815     while ((n /= 10) != 0)
1816         d++;
1817     return d;
1818 }
1819
1820 /* --------------------------------------------------------------------------------------------- */
1821
1822 static int
1823 get_line_numbers (const GArray *a, size_t pos, int *linenum, int *lineofs)
1824 {
1825     const DIFFLN *p;
1826
1827     *linenum = 0;
1828     *lineofs = 0;
1829
1830     if (a->len != 0)
1831     {
1832         if (pos >= a->len)
1833             pos = a->len - 1;
1834
1835         p = &g_array_index (a, DIFFLN, pos);
1836
1837         if (p->line == 0)
1838         {
1839             int n;
1840
1841             for (n = pos; n > 0; n--)
1842             {
1843                 p--;
1844                 if (p->line != 0)
1845                     break;
1846             }
1847             *lineofs = pos - n + 1;
1848         }
1849
1850         *linenum = p->line;
1851     }
1852     return 0;
1853 }
1854
1855 /* --------------------------------------------------------------------------------------------- */
1856
1857 static int
1858 calc_nwidth (const GArray *const *a)
1859 {
1860     int l1, o1;
1861     int l2, o2;
1862
1863     get_line_numbers (a[DIFF_LEFT], a[DIFF_LEFT]->len - 1, &l1, &o1);
1864     get_line_numbers (a[DIFF_RIGHT], a[DIFF_RIGHT]->len - 1, &l2, &o2);
1865     if (l1 < l2)
1866         l1 = l2;
1867     return get_digits (l1);
1868 }
1869
1870 /* --------------------------------------------------------------------------------------------- */
1871
1872 static int
1873 find_prev_hunk (const GArray *a, int pos)
1874 {
1875 #if 1
1876     for (; pos > 0 && ((DIFFLN *) &g_array_index (a, DIFFLN, pos))->ch != EQU_CH; pos--)
1877         ;
1878     for (; pos > 0 && ((DIFFLN *) &g_array_index (a, DIFFLN, pos))->ch == EQU_CH; pos--)
1879         ;
1880     for (; pos > 0 && ((DIFFLN *) &g_array_index (a, DIFFLN, pos))->ch != EQU_CH; pos--)
1881         ;
1882     if (pos > 0 && (size_t) pos < a->len)
1883         pos++;
1884 #else
1885     for (; pos > 0 && ((DIFFLN *) &g_array_index (a, DIFFLN, pos - 1))->ch == EQU_CH; pos--)
1886         ;
1887     for (; pos > 0 && ((DIFFLN *) &g_array_index (a, DIFFLN, pos - 1))->ch != EQU_CH; pos--)
1888         ;
1889 #endif
1890
1891     return pos;
1892 }
1893
1894 /* --------------------------------------------------------------------------------------------- */
1895
1896 static size_t
1897 find_next_hunk (const GArray *a, size_t pos)
1898 {
1899     for (; pos < a->len && ((DIFFLN *) &g_array_index (a, DIFFLN, pos))->ch != EQU_CH; pos++)
1900         ;
1901     for (; pos < a->len && ((DIFFLN *) &g_array_index (a, DIFFLN, pos))->ch == EQU_CH; pos++)
1902         ;
1903     return pos;
1904 }
1905
1906 /* --------------------------------------------------------------------------------------------- */
1907 /**
1908  * Find start and end lines of the current hunk.
1909  *
1910  * @param dview WDiff widget
1911  * @return boolean and
1912  * start_line1 first line of current hunk (file[0])
1913  * end_line1 last line of current hunk (file[0])
1914  * start_line1 first line of current hunk (file[0])
1915  * end_line1 last line of current hunk (file[0])
1916  */
1917
1918 static int
1919 get_current_hunk (WDiff *dview, int *start_line1, int *end_line1, int *start_line2, int *end_line2)
1920 {
1921     const GArray *a0 = dview->a[DIFF_LEFT];
1922     const GArray *a1 = dview->a[DIFF_RIGHT];
1923     size_t pos;
1924     int ch;
1925     int res = 0;
1926
1927     // Is file empty?
1928     if (a0->len == 0)
1929         return 0;
1930
1931     *start_line1 = 1;
1932     *start_line2 = 1;
1933     *end_line1 = 1;
1934     *end_line2 = 1;
1935
1936     pos = dview->skip_rows;
1937     ch = ((DIFFLN *) &g_array_index (a0, DIFFLN, pos))->ch;
1938     if (ch != EQU_CH)
1939     {
1940         switch (ch)
1941         {
1942         case ADD_CH:
1943             res = DIFF_DEL;
1944             break;
1945         case DEL_CH:
1946             res = DIFF_ADD;
1947             break;
1948         case CHG_CH:
1949             res = DIFF_CHG;
1950             break;
1951         default:
1952             break;
1953         }
1954
1955         for (; pos > 0 && ((DIFFLN *) &g_array_index (a0, DIFFLN, pos))->ch != EQU_CH; pos--)
1956             ;
1957         if (pos > 0)
1958         {
1959             *start_line1 = ((DIFFLN *) &g_array_index (a0, DIFFLN, pos))->line + 1;
1960             *start_line2 = ((DIFFLN *) &g_array_index (a1, DIFFLN, pos))->line + 1;
1961         }
1962
1963         for (pos = dview->skip_rows;
1964              pos < a0->len && ((DIFFLN *) &g_array_index (a0, DIFFLN, pos))->ch != EQU_CH; pos++)
1965         {
1966             int l0, l1;
1967
1968             l0 = ((DIFFLN *) &g_array_index (a0, DIFFLN, pos))->line;
1969             l1 = ((DIFFLN *) &g_array_index (a1, DIFFLN, pos))->line;
1970             if (l0 > 0)
1971                 *end_line1 = MAX (*start_line1, l0);
1972             if (l1 > 0)
1973                 *end_line2 = MAX (*start_line2, l1);
1974         }
1975     }
1976     return res;
1977 }
1978
1979 /* --------------------------------------------------------------------------------------------- */
1980 /**
1981  * Remove hunk from file.
1982  *
1983  * @param dview           WDiff widget
1984  * @param merge_file      file stream for writing data
1985  * @param from1           first line of hunk
1986  * @param to1             last line of hunk
1987  * @param merge_direction in what direction files should be merged
1988  */
1989
1990 static void
1991 dview_remove_hunk (WDiff *dview, FILE *merge_file, int from1, int to1,
1992                    action_direction_t merge_direction)
1993 {
1994     int line;
1995     char buf[BUF_10K];
1996     FILE *f0;
1997
1998     if (merge_direction == FROM_RIGHT_TO_LEFT)
1999         f0 = fopen (dview->file[DIFF_RIGHT], "r");
2000     else
2001         f0 = fopen (dview->file[DIFF_LEFT], "r");
2002
2003     for (line = 0; fgets (buf, sizeof (buf), f0) != NULL && line < from1 - 1; line++)
2004         fputs (buf, merge_file);
2005
2006     while (fgets (buf, sizeof (buf), f0) != NULL)
2007     {
2008         line++;
2009         if (line >= to1)
2010             fputs (buf, merge_file);
2011     }
2012     fclose (f0);
2013 }
2014
2015 /* --------------------------------------------------------------------------------------------- */
2016 /**
2017  * Add hunk to file.
2018  *
2019  * @param dview           WDiff widget
2020  * @param merge_file      file stream for writing data
2021  * @param from1           first line of source hunk
2022  * @param from2           first line of destination hunk
2023  * @param to1             last line of source hunk
2024  * @param merge_direction in what direction files should be merged
2025  */
2026
2027 static void
2028 dview_add_hunk (WDiff *dview, FILE *merge_file, int from1, int from2, int to2,
2029                 action_direction_t merge_direction)
2030 {
2031     int line;
2032     char buf[BUF_10K];
2033     FILE *f0, *f1;
2034
2035     if (merge_direction == FROM_RIGHT_TO_LEFT)
2036     {
2037         f0 = fopen (dview->file[DIFF_RIGHT], "r");
2038         f1 = fopen (dview->file[DIFF_LEFT], "r");
2039     }
2040     else
2041     {
2042         f0 = fopen (dview->file[DIFF_LEFT], "r");
2043         f1 = fopen (dview->file[DIFF_RIGHT], "r");
2044     }
2045
2046     for (line = 0; fgets (buf, sizeof (buf), f0) != NULL && line < from1 - 1; line++)
2047         fputs (buf, merge_file);
2048     for (line = 0; fgets (buf, sizeof (buf), f1) != NULL && line <= to2;)
2049     {
2050         line++;
2051         if (line >= from2)
2052             fputs (buf, merge_file);
2053     }
2054     while (fgets (buf, sizeof (buf), f0) != NULL)
2055         fputs (buf, merge_file);
2056
2057     fclose (f0);
2058     fclose (f1);
2059 }
2060
2061 /* --------------------------------------------------------------------------------------------- */
2062 /**
2063  * Replace hunk in file.
2064  *
2065  * @param dview           WDiff widget
2066  * @param merge_file      file stream for writing data
2067  * @param from1           first line of source hunk
2068  * @param to1             last line of source hunk
2069  * @param from2           first line of destination hunk
2070  * @param to2             last line of destination hunk
2071  * @param merge_direction in what direction files should be merged
2072  */
2073
2074 static void
2075 dview_replace_hunk (WDiff *dview, FILE *merge_file, int from1, int to1, int from2, int to2,
2076                     action_direction_t merge_direction)
2077 {
2078     int line1, line2;
2079     char buf[BUF_10K];
2080     FILE *f0, *f1;
2081
2082     if (merge_direction == FROM_RIGHT_TO_LEFT)
2083     {
2084         f0 = fopen (dview->file[DIFF_RIGHT], "r");
2085         f1 = fopen (dview->file[DIFF_LEFT], "r");
2086     }
2087     else
2088     {
2089         f0 = fopen (dview->file[DIFF_LEFT], "r");
2090         f1 = fopen (dview->file[DIFF_RIGHT], "r");
2091     }
2092
2093     for (line1 = 0; fgets (buf, sizeof (buf), f0) != NULL && line1 < from1 - 1; line1++)
2094         fputs (buf, merge_file);
2095     for (line2 = 0; fgets (buf, sizeof (buf), f1) != NULL && line2 <= to2;)
2096     {
2097         line2++;
2098         if (line2 >= from2)
2099             fputs (buf, merge_file);
2100     }
2101     while (fgets (buf, sizeof (buf), f0) != NULL)
2102     {
2103         line1++;
2104         if (line1 > to1)
2105             fputs (buf, merge_file);
2106     }
2107     fclose (f0);
2108     fclose (f1);
2109 }
2110
2111 /* --------------------------------------------------------------------------------------------- */
2112 /**
2113  * Merge hunk.
2114  *
2115  * @param dview           WDiff widget
2116  * @param merge_direction in what direction files should be merged
2117  */
2118
2119 static void
2120 do_merge_hunk (WDiff *dview, action_direction_t merge_direction)
2121 {
2122     int from1, to1, from2, to2;
2123     int hunk;
2124     diff_place_t n_merge = (merge_direction == FROM_RIGHT_TO_LEFT) ? DIFF_RIGHT : DIFF_LEFT;
2125
2126     if (merge_direction == FROM_RIGHT_TO_LEFT)
2127         hunk = get_current_hunk (dview, &from2, &to2, &from1, &to1);
2128     else
2129         hunk = get_current_hunk (dview, &from1, &to1, &from2, &to2);
2130
2131     if (hunk > 0)
2132     {
2133         int merge_file_fd;
2134         FILE *merge_file;
2135         vfs_path_t *merge_file_name_vpath = NULL;
2136
2137         if (!dview->merged[n_merge])
2138         {
2139             dview->merged[n_merge] = mc_util_make_backup_if_possible (dview->file[n_merge], "~~~");
2140             if (!dview->merged[n_merge])
2141             {
2142                 message (D_ERROR, MSG_ERROR, _ ("Cannot create backup file\n%s%s\n%s"),
2143                          dview->file[n_merge], "~~~", unix_error_string (errno));
2144                 return;
2145             }
2146         }
2147
2148         merge_file_fd = mc_mkstemps (&merge_file_name_vpath, "mcmerge", NULL);
2149         if (merge_file_fd == -1)
2150         {
2151             message (D_ERROR, MSG_ERROR, _ ("Cannot create temporary merge file\n%s"),
2152                      unix_error_string (errno));
2153             return;
2154         }
2155
2156         merge_file = fdopen (merge_file_fd, "w");
2157
2158         switch (hunk)
2159         {
2160         case DIFF_DEL:
2161             if (merge_direction == FROM_RIGHT_TO_LEFT)
2162                 dview_add_hunk (dview, merge_file, from1, from2, to2, FROM_RIGHT_TO_LEFT);
2163             else
2164                 dview_remove_hunk (dview, merge_file, from1, to1, FROM_LEFT_TO_RIGHT);
2165             break;
2166         case DIFF_ADD:
2167             if (merge_direction == FROM_RIGHT_TO_LEFT)
2168                 dview_remove_hunk (dview, merge_file, from1, to1, FROM_RIGHT_TO_LEFT);
2169             else
2170                 dview_add_hunk (dview, merge_file, from1, from2, to2, FROM_LEFT_TO_RIGHT);
2171             break;
2172         case DIFF_CHG:
2173             dview_replace_hunk (dview, merge_file, from1, to1, from2, to2, merge_direction);
2174             break;
2175         default:
2176             break;
2177         }
2178         fflush (merge_file);
2179         fclose (merge_file);
2180         {
2181             int res;
2182
2183             res = rewrite_backup_content (merge_file_name_vpath, dview->file[n_merge]);
2184             (void) res;
2185         }
2186         mc_unlink (merge_file_name_vpath);
2187         vfs_path_free (merge_file_name_vpath, TRUE);
2188     }
2189 }
2190
2191 /* --------------------------------------------------------------------------------------------- */
2192 /* view routines and callbacks ********************************************** */
2193
2194 static void
2195 dview_compute_split (WDiff *dview, int i)
2196 {
2197     dview->bias += i;
2198     if (dview->bias < 2 - dview->half1)
2199         dview->bias = 2 - dview->half1;
2200     if (dview->bias > dview->half2 - 2)
2201         dview->bias = dview->half2 - 2;
2202 }
2203
2204 /* --------------------------------------------------------------------------------------------- */
2205
2206 static void
2207 dview_compute_areas (WDiff *dview)
2208 {
2209     Widget *w = WIDGET (dview);
2210
2211     dview->height = w->rect.lines - 1;
2212     dview->half1 = w->rect.cols / 2;
2213     dview->half2 = w->rect.cols - dview->half1;
2214
2215     dview_compute_split (dview, 0);
2216 }
2217
2218 /* --------------------------------------------------------------------------------------------- */
2219
2220 static void
2221 dview_reread (WDiff *dview)
2222 {
2223     int ndiff;
2224
2225     destroy_hdiff (dview);
2226     if (dview->a[DIFF_LEFT] != NULL)
2227         g_array_free (dview->a[DIFF_LEFT], TRUE);
2228     if (dview->a[DIFF_RIGHT] != NULL)
2229         g_array_free (dview->a[DIFF_RIGHT], TRUE);
2230
2231     dview->a[DIFF_LEFT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
2232     g_array_set_clear_func (dview->a[DIFF_LEFT], cc_free_elt);
2233     dview->a[DIFF_RIGHT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
2234     g_array_set_clear_func (dview->a[DIFF_RIGHT], cc_free_elt);
2235
2236     ndiff = redo_diff (dview);
2237     if (ndiff >= 0)
2238         dview->ndiff = ndiff;
2239 }
2240
2241 /* --------------------------------------------------------------------------------------------- */
2242
2243 #ifdef HAVE_CHARSET
2244 static void
2245 dview_set_codeset (WDiff *dview)
2246 {
2247     const char *encoding_id = NULL;
2248
2249     dview->utf8 = TRUE;
2250     encoding_id = get_codepage_id (mc_global.source_codepage >= 0 ? mc_global.source_codepage
2251                                                                   : mc_global.display_codepage);
2252     if (encoding_id != NULL)
2253     {
2254         GIConv conv;
2255
2256         conv = str_crt_conv_from (encoding_id);
2257         if (conv != INVALID_CONV)
2258         {
2259             if (dview->converter != str_cnv_from_term)
2260                 str_close_conv (dview->converter);
2261             dview->converter = conv;
2262         }
2263         dview->utf8 = (gboolean) str_isutf8 (encoding_id);
2264     }
2265 }
2266
2267 /* --------------------------------------------------------------------------------------------- */
2268
2269 static void
2270 dview_select_encoding (WDiff *dview)
2271 {
2272     if (do_select_codepage ())
2273         dview_set_codeset (dview);
2274     dview_reread (dview);
2275     tty_touch_screen ();
2276     repaint_screen ();
2277 }
2278 #endif
2279
2280 /* --------------------------------------------------------------------------------------------- */
2281
2282 static void
2283 dview_load_options (WDiff *dview)
2284 {
2285     gboolean show_numbers;
2286     int tab_size;
2287
2288     dview->display_symbols =
2289         mc_config_get_bool (mc_global.main_config, "DiffView", "show_symbols", FALSE);
2290     show_numbers = mc_config_get_bool (mc_global.main_config, "DiffView", "show_numbers", FALSE);
2291     if (show_numbers)
2292         dview->display_numbers = 1;
2293     tab_size = mc_config_get_int (mc_global.main_config, "DiffView", "tab_size", 8);
2294     if (tab_size > 0 && tab_size < 9)
2295         dview->tab_size = tab_size;
2296     else
2297         dview->tab_size = 8;
2298
2299     dview->opt.quality = mc_config_get_int (mc_global.main_config, "DiffView", "diff_quality", 0);
2300
2301     dview->opt.strip_trailing_cr =
2302         mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_tws", FALSE);
2303     dview->opt.ignore_all_space =
2304         mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_all_space", FALSE);
2305     dview->opt.ignore_space_change =
2306         mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_space_change", FALSE);
2307     dview->opt.ignore_tab_expansion =
2308         mc_config_get_bool (mc_global.main_config, "DiffView", "diff_tab_expansion", FALSE);
2309     dview->opt.ignore_case =
2310         mc_config_get_bool (mc_global.main_config, "DiffView", "diff_ignore_case", FALSE);
2311
2312     dview->new_frame = TRUE;
2313 }
2314
2315 /* --------------------------------------------------------------------------------------------- */
2316
2317 static void
2318 dview_save_options (WDiff *dview)
2319 {
2320     mc_config_set_bool (mc_global.main_config, "DiffView", "show_symbols", dview->display_symbols);
2321     mc_config_set_bool (mc_global.main_config, "DiffView", "show_numbers",
2322                         dview->display_numbers != 0);
2323     mc_config_set_int (mc_global.main_config, "DiffView", "tab_size", dview->tab_size);
2324
2325     mc_config_set_int (mc_global.main_config, "DiffView", "diff_quality", dview->opt.quality);
2326
2327     mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_tws",
2328                         dview->opt.strip_trailing_cr);
2329     mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_all_space",
2330                         dview->opt.ignore_all_space);
2331     mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_space_change",
2332                         dview->opt.ignore_space_change);
2333     mc_config_set_bool (mc_global.main_config, "DiffView", "diff_tab_expansion",
2334                         dview->opt.ignore_tab_expansion);
2335     mc_config_set_bool (mc_global.main_config, "DiffView", "diff_ignore_case",
2336                         dview->opt.ignore_case);
2337 }
2338
2339 /* --------------------------------------------------------------------------------------------- */
2340
2341 static void
2342 dview_diff_options (WDiff *dview)
2343 {
2344     const char *quality_str[] = {
2345         N_ ("No&rmal"),
2346         N_ ("&Fastest (Assume large files)"),
2347         N_ ("&Minimal (Find a smaller set of change)"),
2348     };
2349
2350     quick_widget_t quick_widgets[] = {
2351         // clang-format off
2352         QUICK_START_GROUPBOX (N_ ("Diff algorithm")),
2353             QUICK_RADIO (3, (const char **) quality_str, (int *) &dview->opt.quality, NULL),
2354         QUICK_STOP_GROUPBOX,
2355         QUICK_START_GROUPBOX (N_ ("Diff extra options")),
2356             QUICK_CHECKBOX (N_ ("&Ignore case"), &dview->opt.ignore_case, NULL),
2357             QUICK_CHECKBOX (N_ ("Ignore tab &expansion"), &dview->opt.ignore_tab_expansion, NULL),
2358             QUICK_CHECKBOX (N_ ("Ignore &space change"), &dview->opt.ignore_space_change, NULL),
2359             QUICK_CHECKBOX (N_ ("Ignore all &whitespace"), &dview->opt.ignore_all_space, NULL),
2360             QUICK_CHECKBOX (N_ ("Strip &trailing carriage return"), &dview->opt.strip_trailing_cr,
2361                             NULL),
2362         QUICK_STOP_GROUPBOX,
2363         QUICK_BUTTONS_OK_CANCEL,
2364         QUICK_END,
2365         // clang-format on
2366     };
2367
2368     WRect r = { -1, -1, 0, 56 };
2369
2370     quick_dialog_t qdlg = {
2371         .rect = r,
2372         .title = N_ ("Diff Options"),
2373         .help = "[Diff Options]",
2374         .widgets = quick_widgets,
2375         .callback = NULL,
2376         .mouse_callback = NULL,
2377     };
2378
2379     if (quick_dialog (&qdlg) != B_CANCEL)
2380         dview_reread (dview);
2381 }
2382
2383 /* --------------------------------------------------------------------------------------------- */
2384
2385 static int
2386 dview_init (WDiff *dview, const char *args, const char *file1, const char *file2,
2387             const char *label1, const char *label2, DSRC dsrc)
2388 {
2389     FBUF *f[DIFF_COUNT];
2390
2391     f[DIFF_LEFT] = NULL;
2392     f[DIFF_RIGHT] = NULL;
2393
2394     if (dsrc == DATA_SRC_TMP)
2395     {
2396         f[DIFF_LEFT] = dview_ftemp ();
2397         if (f[DIFF_LEFT] == NULL)
2398             return -1;
2399
2400         f[DIFF_RIGHT] = dview_ftemp ();
2401         if (f[DIFF_RIGHT] == NULL)
2402         {
2403             dview_fclose (f[DIFF_LEFT]);
2404             return -1;
2405         }
2406     }
2407     else if (dsrc == DATA_SRC_ORG)
2408     {
2409         f[DIFF_LEFT] = dview_fopen (file1, O_RDONLY);
2410         if (f[DIFF_LEFT] == NULL)
2411             return -1;
2412
2413         f[DIFF_RIGHT] = dview_fopen (file2, O_RDONLY);
2414         if (f[DIFF_RIGHT] == NULL)
2415         {
2416             dview_fclose (f[DIFF_LEFT]);
2417             return -1;
2418         }
2419     }
2420
2421     dview->view_quit = FALSE;
2422
2423     dview->bias = 0;
2424     dview->new_frame = TRUE;
2425     dview->skip_rows = 0;
2426     dview->skip_cols = 0;
2427     dview->display_symbols = FALSE;
2428     dview->display_numbers = 0;
2429     dview->show_cr = TRUE;
2430     dview->tab_size = 8;
2431     dview->ord = DIFF_LEFT;
2432     dview->full = FALSE;
2433
2434     dview->search.handle = NULL;
2435     dview->search.last_string = NULL;
2436     dview->search.last_found_line = -1;
2437     dview->search.last_accessed_num_line = -1;
2438
2439     dview_load_options (dview);
2440
2441     dview->args = args;
2442     dview->file[DIFF_LEFT] = file1;
2443     dview->file[DIFF_RIGHT] = file2;
2444     dview->label[DIFF_LEFT] = g_strdup (label1);
2445     dview->label[DIFF_RIGHT] = g_strdup (label2);
2446     dview->f[DIFF_LEFT] = f[0];
2447     dview->f[DIFF_RIGHT] = f[1];
2448     dview->merged[DIFF_LEFT] = FALSE;
2449     dview->merged[DIFF_RIGHT] = FALSE;
2450     dview->hdiff = NULL;
2451     dview->dsrc = dsrc;
2452 #ifdef HAVE_CHARSET
2453     dview->converter = str_cnv_from_term;
2454     dview_set_codeset (dview);
2455 #endif
2456     dview->a[DIFF_LEFT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
2457     g_array_set_clear_func (dview->a[DIFF_LEFT], cc_free_elt);
2458     dview->a[DIFF_RIGHT] = g_array_new (FALSE, FALSE, sizeof (DIFFLN));
2459     g_array_set_clear_func (dview->a[DIFF_RIGHT], cc_free_elt);
2460
2461     return 0;
2462 }
2463
2464 /* --------------------------------------------------------------------------------------------- */
2465
2466 static void
2467 dview_fini (WDiff *dview)
2468 {
2469     if (dview->dsrc != DATA_SRC_MEM)
2470     {
2471         dview_fclose (dview->f[DIFF_RIGHT]);
2472         dview_fclose (dview->f[DIFF_LEFT]);
2473     }
2474
2475 #ifdef HAVE_CHARSET
2476     if (dview->converter != str_cnv_from_term)
2477         str_close_conv (dview->converter);
2478 #endif
2479
2480     destroy_hdiff (dview);
2481     if (dview->a[DIFF_LEFT] != NULL)
2482     {
2483         g_array_free (dview->a[DIFF_LEFT], TRUE);
2484         dview->a[DIFF_LEFT] = NULL;
2485     }
2486     if (dview->a[DIFF_RIGHT] != NULL)
2487     {
2488         g_array_free (dview->a[DIFF_RIGHT], TRUE);
2489         dview->a[DIFF_RIGHT] = NULL;
2490     }
2491
2492     g_free (dview->label[DIFF_LEFT]);
2493     g_free (dview->label[DIFF_RIGHT]);
2494 }
2495
2496 /* --------------------------------------------------------------------------------------------- */
2497
2498 static int
2499 dview_display_file (const WDiff *dview, diff_place_t ord, int r, int c, int height, int width)
2500 {
2501     size_t i, k;
2502     int j;
2503     char buf[BUFSIZ];
2504     FBUF *f = dview->f[ord];
2505     int skip = dview->skip_cols;
2506     gboolean display_symbols = dview->display_symbols;
2507     int display_numbers = dview->display_numbers;
2508     gboolean show_cr = dview->show_cr;
2509     int tab_size = 8;
2510     const DIFFLN *p;
2511     int nwidth = display_numbers;
2512     int xwidth;
2513
2514     xwidth = display_numbers;
2515     if (display_symbols)
2516         xwidth++;
2517     if (dview->tab_size > 0 && dview->tab_size < 9)
2518         tab_size = dview->tab_size;
2519
2520     if (xwidth != 0)
2521     {
2522         if (xwidth > width && display_symbols)
2523         {
2524             xwidth--;
2525             display_symbols = FALSE;
2526         }
2527         if (xwidth > width && display_numbers != 0)
2528         {
2529             xwidth = width;
2530             display_numbers = width;
2531         }
2532
2533         xwidth++;
2534         c += xwidth;
2535         width -= xwidth;
2536         if (width < 0)
2537             width = 0;
2538     }
2539
2540     if ((int) sizeof (buf) <= width || (int) sizeof (buf) <= nwidth)
2541     {
2542         // abnormal, but avoid buffer overflow
2543         return -1;
2544     }
2545
2546     for (i = dview->skip_rows, j = 0; i < dview->a[ord]->len && j < height; j++, i++)
2547     {
2548         int ch;
2549         int next_ch = 0;
2550         int col;
2551         size_t cnt;
2552
2553         p = (DIFFLN *) &g_array_index (dview->a[ord], DIFFLN, i);
2554         ch = p->ch;
2555         tty_setcolor (NORMAL_COLOR);
2556         if (display_symbols)
2557         {
2558             tty_gotoyx (r + j, c - 2);
2559             tty_print_char (ch);
2560         }
2561         if (p->line != 0)
2562         {
2563             if (display_numbers != 0)
2564             {
2565                 tty_gotoyx (r + j, c - xwidth);
2566                 g_snprintf (buf, display_numbers + 1, "%*d", nwidth, p->line);
2567                 tty_print_string (str_fit_to_term (buf, nwidth, J_LEFT_FIT));
2568             }
2569             if (ch == ADD_CH)
2570                 tty_setcolor (DFF_ADD_COLOR);
2571             if (ch == CHG_CH)
2572                 tty_setcolor (DFF_CHG_COLOR);
2573             if (f == NULL)
2574             {
2575                 if (i == (size_t) dview->search.last_found_line)
2576                     tty_setcolor (MARKED_SELECTED_COLOR);
2577                 else if (dview->hdiff != NULL && g_ptr_array_index (dview->hdiff, i) != NULL)
2578                 {
2579                     char att[BUFSIZ];
2580
2581 #ifdef HAVE_CHARSET
2582                     if (dview->utf8)
2583                         k = dview_str_utf8_offset_to_pos (p->p, width);
2584                     else
2585 #endif
2586                         k = width;
2587
2588                     cvt_mgeta (p->p, p->u.len, buf, k, skip, tab_size, show_cr,
2589                                g_ptr_array_index (dview->hdiff, i), ord, att);
2590                     tty_gotoyx (r + j, c);
2591                     col = 0;
2592
2593                     for (cnt = 0; cnt < strlen (buf) && col < width; cnt++)
2594                     {
2595                         gboolean ch_res;
2596
2597 #ifdef HAVE_CHARSET
2598                         if (dview->utf8)
2599                         {
2600                             int ch_length = 0;
2601
2602                             ch_res = dview_get_utf (buf + cnt, &next_ch, &ch_length);
2603                             if (ch_length > 1)
2604                                 cnt += ch_length - 1;
2605                             if (!g_unichar_isprint (next_ch))
2606                                 next_ch = '.';
2607                         }
2608                         else
2609 #endif
2610                             ch_res = dview_get_byte (buf + cnt, &next_ch);
2611
2612                         if (ch_res)
2613                         {
2614                             tty_setcolor (att[cnt] ? DFF_CHH_COLOR : DFF_CHG_COLOR);
2615 #ifdef HAVE_CHARSET
2616                             if (mc_global.utf8_display)
2617                             {
2618                                 if (!dview->utf8)
2619                                 {
2620                                     next_ch = convert_from_8bit_to_utf_c ((unsigned char) next_ch,
2621                                                                           dview->converter);
2622                                 }
2623                             }
2624                             else if (dview->utf8)
2625                                 next_ch = convert_from_utf_to_current_c (next_ch, dview->converter);
2626                             else
2627                                 next_ch = convert_to_display_c (next_ch);
2628 #endif
2629                             tty_print_anychar (next_ch);
2630                             col++;
2631                         }
2632                     }
2633                     continue;
2634                 }
2635
2636                 if (ch == CHG_CH)
2637                     tty_setcolor (DFF_CHH_COLOR);
2638
2639 #ifdef HAVE_CHARSET
2640                 if (dview->utf8)
2641                     k = dview_str_utf8_offset_to_pos (p->p, width);
2642                 else
2643 #endif
2644                     k = width;
2645                 cvt_mget (p->p, p->u.len, buf, k, skip, tab_size, show_cr);
2646             }
2647             else
2648                 cvt_fget (f, p->u.off, buf, width, skip, tab_size, show_cr);
2649         }
2650         else
2651         {
2652             if (display_numbers != 0)
2653             {
2654                 tty_gotoyx (r + j, c - xwidth);
2655                 fill_by_space (buf, display_numbers, TRUE);
2656                 tty_print_string (buf);
2657             }
2658             if (ch == DEL_CH)
2659                 tty_setcolor (DFF_DEL_COLOR);
2660             if (ch == CHG_CH)
2661                 tty_setcolor (DFF_CHD_COLOR);
2662             fill_by_space (buf, width, TRUE);
2663         }
2664         tty_gotoyx (r + j, c);
2665         // tty_print_nstring (buf, width);
2666         col = 0;
2667         for (cnt = 0; cnt < strlen (buf) && col < width; cnt++)
2668         {
2669             gboolean ch_res;
2670
2671 #ifdef HAVE_CHARSET
2672             if (dview->utf8)
2673             {
2674                 int ch_length = 0;
2675
2676                 ch_res = dview_get_utf (buf + cnt, &next_ch, &ch_length);
2677                 if (ch_length > 1)
2678                     cnt += ch_length - 1;
2679                 if (!g_unichar_isprint (next_ch))
2680                     next_ch = '.';
2681             }
2682             else
2683 #endif
2684                 ch_res = dview_get_byte (buf + cnt, &next_ch);
2685
2686             if (ch_res)
2687             {
2688 #ifdef HAVE_CHARSET
2689                 if (mc_global.utf8_display)
2690                 {
2691                     if (!dview->utf8)
2692                         next_ch =
2693                             convert_from_8bit_to_utf_c ((unsigned char) next_ch, dview->converter);
2694                 }
2695                 else if (dview->utf8)
2696                     next_ch = convert_from_utf_to_current_c (next_ch, dview->converter);
2697                 else
2698                     next_ch = convert_to_display_c (next_ch);
2699 #endif
2700
2701                 tty_print_anychar (next_ch);
2702                 col++;
2703             }
2704         }
2705     }
2706     tty_setcolor (NORMAL_COLOR);
2707     k = width;
2708     if (width < xwidth - 1)
2709         k = xwidth - 1;
2710     fill_by_space (buf, k, TRUE);
2711     for (; j < height; j++)
2712     {
2713         if (xwidth != 0)
2714         {
2715             tty_gotoyx (r + j, c - xwidth);
2716             // tty_print_nstring (buf, xwidth - 1);
2717             tty_print_string (str_fit_to_term (buf, xwidth - 1, J_LEFT_FIT));
2718         }
2719         tty_gotoyx (r + j, c);
2720         // tty_print_nstring (buf, width);
2721         tty_print_string (str_fit_to_term (buf, width, J_LEFT_FIT));
2722     }
2723
2724     return 0;
2725 }
2726
2727 /* --------------------------------------------------------------------------------------------- */
2728
2729 static void
2730 dview_status (const WDiff *dview, diff_place_t ord, int width, int c)
2731 {
2732     const char *buf;
2733     int filename_width;
2734     int linenum, lineofs;
2735     vfs_path_t *vpath;
2736     char *path;
2737
2738     tty_setcolor (STATUSBAR_COLOR);
2739
2740     tty_gotoyx (0, c);
2741     get_line_numbers (dview->a[ord], dview->skip_rows, &linenum, &lineofs);
2742
2743     filename_width = width - 24;
2744     if (filename_width < 8)
2745         filename_width = 8;
2746
2747     vpath = vfs_path_from_str (dview->label[ord]);
2748     path = vfs_path_to_str_flags (vpath, 0, VPF_STRIP_HOME | VPF_STRIP_PASSWORD);
2749     vfs_path_free (vpath, TRUE);
2750     buf = str_term_trim (path, filename_width);
2751     if (ord == DIFF_LEFT)
2752         tty_printf ("%s%-*s %6d+%-4d Col %-4d ", dview->merged[ord] ? "* " : "  ", filename_width,
2753                     buf, linenum, lineofs, dview->skip_cols);
2754     else
2755         tty_printf ("%s%-*s %6d+%-4d Dif %-4d ", dview->merged[ord] ? "* " : "  ", filename_width,
2756                     buf, linenum, lineofs, dview->ndiff);
2757     g_free (path);
2758 }
2759
2760 /* --------------------------------------------------------------------------------------------- */
2761
2762 static void
2763 dview_redo (WDiff *dview)
2764 {
2765     if (dview->display_numbers != 0)
2766     {
2767         int old;
2768
2769         old = dview->display_numbers;
2770         dview->display_numbers = calc_nwidth ((const GArray *const *) dview->a);
2771         dview->new_frame = (old != dview->display_numbers);
2772     }
2773     dview_reread (dview);
2774 }
2775
2776 /* --------------------------------------------------------------------------------------------- */
2777
2778 static void
2779 dview_update (WDiff *dview)
2780 {
2781     int height = dview->height;
2782     int width1, width2;
2783     int last;
2784
2785     last = dview->a[DIFF_LEFT]->len - 1;
2786
2787     if (dview->skip_rows > last)
2788         dview->skip_rows = dview->search.last_accessed_num_line = last;
2789     if (dview->skip_rows < 0)
2790         dview->skip_rows = dview->search.last_accessed_num_line = 0;
2791     if (dview->skip_cols < 0)
2792         dview->skip_cols = 0;
2793
2794     if (height < 2)
2795         return;
2796
2797     // use an actual length of dview->a
2798     if (dview->display_numbers != 0)
2799         dview->display_numbers = calc_nwidth ((const GArray *const *) dview->a);
2800
2801     width1 = dview->half1 + dview->bias;
2802     width2 = dview->half2 - dview->bias;
2803     if (dview->full)
2804     {
2805         width1 = COLS;
2806         width2 = 0;
2807     }
2808
2809     if (dview->new_frame)
2810     {
2811         int xwidth;
2812
2813         tty_setcolor (NORMAL_COLOR);
2814         xwidth = dview->display_numbers;
2815         if (dview->display_symbols)
2816             xwidth++;
2817         if (width1 > 1)
2818             tty_draw_box (1, 0, height, width1, FALSE);
2819         if (width2 > 1)
2820             tty_draw_box (1, width1, height, width2, FALSE);
2821
2822         if (xwidth != 0)
2823         {
2824             xwidth++;
2825             if (xwidth < width1 - 1)
2826             {
2827                 tty_gotoyx (1, xwidth);
2828                 tty_print_alt_char (ACS_TTEE, FALSE);
2829                 tty_gotoyx (height, xwidth);
2830                 tty_print_alt_char (ACS_BTEE, FALSE);
2831                 tty_draw_vline (2, xwidth, ACS_VLINE, height - 2);
2832             }
2833             if (xwidth < width2 - 1)
2834             {
2835                 tty_gotoyx (1, width1 + xwidth);
2836                 tty_print_alt_char (ACS_TTEE, FALSE);
2837                 tty_gotoyx (height, width1 + xwidth);
2838                 tty_print_alt_char (ACS_BTEE, FALSE);
2839                 tty_draw_vline (2, width1 + xwidth, ACS_VLINE, height - 2);
2840             }
2841         }
2842         dview->new_frame = FALSE;
2843     }
2844
2845     if (width1 > 2)
2846     {
2847         dview_status (dview, dview->ord, width1, 0);
2848         dview_display_file (dview, dview->ord, 2, 1, height - 2, width1 - 2);
2849     }
2850     if (width2 > 2)
2851     {
2852         diff_place_t ord;
2853
2854         ord = dview->ord == DIFF_LEFT ? DIFF_RIGHT : DIFF_LEFT;
2855         dview_status (dview, ord, width2, width1);
2856         dview_display_file (dview, ord, 2, width1 + 1, height - 2, width2 - 2);
2857     }
2858 }
2859
2860 /* --------------------------------------------------------------------------------------------- */
2861
2862 static void
2863 dview_edit (WDiff *dview, diff_place_t ord)
2864 {
2865     Widget *h;
2866     gboolean h_modal;
2867     int linenum, lineofs;
2868
2869     if (dview->dsrc == DATA_SRC_TMP)
2870     {
2871         error_dialog (_ ("Edit"), _ ("Edit is disabled"));
2872         return;
2873     }
2874
2875     h = WIDGET (WIDGET (dview)->owner);
2876     h_modal = widget_get_state (h, WST_MODAL);
2877
2878     get_line_numbers (dview->a[ord], dview->skip_rows, &linenum, &lineofs);
2879
2880     // disallow edit file in several editors
2881     widget_set_state (h, WST_MODAL, TRUE);
2882
2883     {
2884         vfs_path_t *tmp_vpath;
2885
2886         tmp_vpath = vfs_path_from_str (dview->file[ord]);
2887         edit_file_at_line (tmp_vpath, use_internal_edit, linenum);
2888         vfs_path_free (tmp_vpath, TRUE);
2889     }
2890
2891     widget_set_state (h, WST_MODAL, h_modal);
2892     dview_redo (dview);
2893     dview_update (dview);
2894 }
2895
2896 /* --------------------------------------------------------------------------------------------- */
2897
2898 static void
2899 dview_goto_cmd (WDiff *dview, diff_place_t ord)
2900 {
2901     static gboolean first_run = TRUE;
2902
2903     static const char *title[2] = {
2904         N_ ("Goto line (left)"),
2905         N_ ("Goto line (right)"),
2906     };
2907
2908     int newline;
2909     char *input;
2910
2911     input = input_dialog (_ (title[ord]), _ ("Enter line:"), MC_HISTORY_YDIFF_GOTO_LINE,
2912                           first_run ? NULL : INPUT_LAST_TEXT, INPUT_COMPLETE_NONE);
2913     if (input != NULL)
2914     {
2915         const char *s = input;
2916
2917         if (scan_deci (&s, &newline) == 0 && *s == '\0')
2918         {
2919             size_t i = 0;
2920
2921             if (newline > 0)
2922                 for (; i < dview->a[ord]->len; i++)
2923                 {
2924                     const DIFFLN *p;
2925
2926                     p = &g_array_index (dview->a[ord], DIFFLN, i);
2927                     if (p->line == newline)
2928                         break;
2929                 }
2930
2931             dview->skip_rows = dview->search.last_accessed_num_line = (ssize_t) i;
2932         }
2933
2934         g_free (input);
2935     }
2936
2937     first_run = FALSE;
2938 }
2939
2940 /* --------------------------------------------------------------------------------------------- */
2941
2942 static void
2943 dview_labels (WDiff *dview)
2944 {
2945     Widget *d = WIDGET (dview);
2946     WButtonBar *b;
2947
2948     b = buttonbar_find (DIALOG (d->owner));
2949
2950     buttonbar_set_label (b, 1, Q_ ("ButtonBar|Help"), d->keymap, d);
2951     buttonbar_set_label (b, 2, Q_ ("ButtonBar|Save"), d->keymap, d);
2952     buttonbar_set_label (b, 4, Q_ ("ButtonBar|Edit"), d->keymap, d);
2953     buttonbar_set_label (b, 5, Q_ ("ButtonBar|Merge"), d->keymap, d);
2954     buttonbar_set_label (b, 7, Q_ ("ButtonBar|Search"), d->keymap, d);
2955     buttonbar_set_label (b, 9, Q_ ("ButtonBar|Options"), d->keymap, d);
2956     buttonbar_set_label (b, 10, Q_ ("ButtonBar|Quit"), d->keymap, d);
2957 }
2958
2959 /* --------------------------------------------------------------------------------------------- */
2960
2961 static gboolean
2962 dview_save (WDiff *dview)
2963 {
2964     gboolean res = TRUE;
2965
2966     if (dview->merged[DIFF_LEFT])
2967     {
2968         res = mc_util_unlink_backup_if_possible (dview->file[DIFF_LEFT], "~~~");
2969         dview->merged[DIFF_LEFT] = !res;
2970     }
2971     if (dview->merged[DIFF_RIGHT])
2972     {
2973         res = mc_util_unlink_backup_if_possible (dview->file[DIFF_RIGHT], "~~~");
2974         dview->merged[DIFF_RIGHT] = !res;
2975     }
2976     return res;
2977 }
2978
2979 /* --------------------------------------------------------------------------------------------- */
2980
2981 static void
2982 dview_do_save (WDiff *dview)
2983 {
2984     (void) dview_save (dview);
2985 }
2986
2987 /* --------------------------------------------------------------------------------------------- */
2988
2989 /*
2990  * Check if it's OK to close the diff viewer.  If there are unsaved changes,
2991  * ask user.
2992  */
2993 static gboolean
2994 dview_ok_to_exit (WDiff *dview)
2995 {
2996     gboolean res = TRUE;
2997     int act;
2998
2999     if (!dview->merged[DIFF_LEFT] && !dview->merged[DIFF_RIGHT])
3000         return res;
3001
3002     act = query_dialog (_ ("Quit"),
3003                         !mc_global.midnight_shutdown
3004                             ? _ ("File(s) was modified. Save with exit?")
3005                             : _ ("Midnight Commander is being shut down.\nSave modified file(s)?"),
3006                         D_NORMAL, 2, _ ("&Yes"), _ ("&No"));
3007
3008     // Esc is No
3009     if (mc_global.midnight_shutdown || (act == -1))
3010         act = 1;
3011
3012     switch (act)
3013     {
3014     case -1:  // Esc
3015         res = FALSE;
3016         break;
3017     case 0:  // Yes
3018         (void) dview_save (dview);
3019         res = TRUE;
3020         break;
3021     case 1:  // No
3022         if (mc_util_restore_from_backup_if_possible (dview->file[DIFF_LEFT], "~~~"))
3023             res = mc_util_unlink_backup_if_possible (dview->file[DIFF_LEFT], "~~~");
3024         if (mc_util_restore_from_backup_if_possible (dview->file[DIFF_RIGHT], "~~~"))
3025             res = mc_util_unlink_backup_if_possible (dview->file[DIFF_RIGHT], "~~~");
3026         MC_FALLTHROUGH;
3027     default:
3028         res = TRUE;
3029         break;
3030     }
3031     return res;
3032 }
3033
3034 /* --------------------------------------------------------------------------------------------- */
3035
3036 static cb_ret_t
3037 dview_execute_cmd (WDiff *dview, long command)
3038 {
3039     cb_ret_t res = MSG_HANDLED;
3040
3041     switch (command)
3042     {
3043     case CK_ShowSymbols:
3044         dview->display_symbols = !dview->display_symbols;
3045         dview->new_frame = TRUE;
3046         break;
3047     case CK_ShowNumbers:
3048         dview->display_numbers ^= calc_nwidth ((const GArray *const *) dview->a);
3049         dview->new_frame = TRUE;
3050         break;
3051     case CK_SplitFull:
3052         dview->full = !dview->full;
3053         dview->new_frame = TRUE;
3054         break;
3055     case CK_SplitEqual:
3056         if (!dview->full)
3057         {
3058             dview->bias = 0;
3059             dview->new_frame = TRUE;
3060         }
3061         break;
3062     case CK_SplitMore:
3063         if (!dview->full)
3064         {
3065             dview_compute_split (dview, 1);
3066             dview->new_frame = TRUE;
3067         }
3068         break;
3069
3070     case CK_SplitLess:
3071         if (!dview->full)
3072         {
3073             dview_compute_split (dview, -1);
3074             dview->new_frame = TRUE;
3075         }
3076         break;
3077     case CK_Tab2:
3078         dview->tab_size = 2;
3079         break;
3080     case CK_Tab3:
3081         dview->tab_size = 3;
3082         break;
3083     case CK_Tab4:
3084         dview->tab_size = 4;
3085         break;
3086     case CK_Tab8:
3087         dview->tab_size = 8;
3088         break;
3089     case CK_Swap:
3090         dview->ord ^= 1;
3091         break;
3092     case CK_Redo:
3093         dview_redo (dview);
3094         break;
3095     case CK_HunkNext:
3096         dview->skip_rows = dview->search.last_accessed_num_line =
3097             find_next_hunk (dview->a[DIFF_LEFT], dview->skip_rows);
3098         break;
3099     case CK_HunkPrev:
3100         dview->skip_rows = dview->search.last_accessed_num_line =
3101             find_prev_hunk (dview->a[DIFF_LEFT], dview->skip_rows);
3102         break;
3103     case CK_Goto:
3104         dview_goto_cmd (dview, DIFF_RIGHT);
3105         break;
3106     case CK_Edit:
3107         dview_edit (dview, dview->ord);
3108         break;
3109     case CK_Merge:
3110         do_merge_hunk (dview, FROM_LEFT_TO_RIGHT);
3111         dview_redo (dview);
3112         break;
3113     case CK_MergeOther:
3114         do_merge_hunk (dview, FROM_RIGHT_TO_LEFT);
3115         dview_redo (dview);
3116         break;
3117     case CK_EditOther:
3118         dview_edit (dview, dview->ord ^ 1);
3119         break;
3120     case CK_Search:
3121         dview_search_cmd (dview);
3122         break;
3123     case CK_SearchContinue:
3124         dview_continue_search_cmd (dview);
3125         break;
3126     case CK_Top:
3127         dview->skip_rows = dview->search.last_accessed_num_line = 0;
3128         break;
3129     case CK_Bottom:
3130         dview->skip_rows = dview->search.last_accessed_num_line = dview->a[DIFF_LEFT]->len - 1;
3131         break;
3132     case CK_Up:
3133         if (dview->skip_rows > 0)
3134         {
3135             dview->skip_rows--;
3136             dview->search.last_accessed_num_line = dview->skip_rows;
3137         }
3138         break;
3139     case CK_Down:
3140         dview->skip_rows++;
3141         dview->search.last_accessed_num_line = dview->skip_rows;
3142         break;
3143     case CK_PageDown:
3144         if (dview->height > 2)
3145         {
3146             dview->skip_rows += dview->height - 2;
3147             dview->search.last_accessed_num_line = dview->skip_rows;
3148         }
3149         break;
3150     case CK_PageUp:
3151         if (dview->height > 2)
3152         {
3153             dview->skip_rows -= dview->height - 2;
3154             dview->search.last_accessed_num_line = dview->skip_rows;
3155         }
3156         break;
3157     case CK_Left:
3158         dview->skip_cols--;
3159         break;
3160     case CK_Right:
3161         dview->skip_cols++;
3162         break;
3163     case CK_LeftQuick:
3164         dview->skip_cols -= 8;
3165         break;
3166     case CK_RightQuick:
3167         dview->skip_cols += 8;
3168         break;
3169     case CK_Home:
3170         dview->skip_cols = 0;
3171         break;
3172     case CK_Shell:
3173         toggle_subshell ();
3174         break;
3175     case CK_Quit:
3176         dview->view_quit = TRUE;
3177         break;
3178     case CK_Save:
3179         dview_do_save (dview);
3180         break;
3181     case CK_Options:
3182         dview_diff_options (dview);
3183         break;
3184 #ifdef HAVE_CHARSET
3185     case CK_SelectCodepage:
3186         dview_select_encoding (dview);
3187         break;
3188 #endif
3189     case CK_Cancel:
3190         // don't close diffviewer due to SIGINT
3191         break;
3192     default:
3193         res = MSG_NOT_HANDLED;
3194     }
3195     return res;
3196 }
3197
3198 /* --------------------------------------------------------------------------------------------- */
3199
3200 static cb_ret_t
3201 dview_handle_key (WDiff *dview, int key)
3202 {
3203     long command;
3204
3205 #ifdef HAVE_CHARSET
3206     key = convert_from_input_c (key);
3207 #endif
3208
3209     command = widget_lookup_key (WIDGET (dview), key);
3210     if (command == CK_IgnoreKey)
3211         return MSG_NOT_HANDLED;
3212
3213     return dview_execute_cmd (dview, command);
3214 }
3215
3216 /* --------------------------------------------------------------------------------------------- */
3217
3218 static cb_ret_t
3219 dview_callback (Widget *w, Widget *sender, widget_msg_t msg, int parm, void *data)
3220 {
3221     WDiff *dview = (WDiff *) w;
3222     WDialog *h = DIALOG (w->owner);
3223     cb_ret_t i;
3224
3225     switch (msg)
3226     {
3227     case MSG_INIT:
3228         dview_labels (dview);
3229         dview_update (dview);
3230         return MSG_HANDLED;
3231
3232     case MSG_DRAW:
3233         dview->new_frame = TRUE;
3234         dview_update (dview);
3235         return MSG_HANDLED;
3236
3237     case MSG_KEY:
3238         i = dview_handle_key (dview, parm);
3239         if (dview->view_quit)
3240             dlg_close (h);
3241         else
3242             dview_update (dview);
3243         return i;
3244
3245     case MSG_ACTION:
3246         i = dview_execute_cmd (dview, parm);
3247         if (dview->view_quit)
3248             dlg_close (h);
3249         else
3250             dview_update (dview);
3251         return i;
3252
3253     case MSG_RESIZE:
3254         widget_default_callback (w, NULL, MSG_RESIZE, 0, data);
3255         dview_compute_areas (dview);
3256         return MSG_HANDLED;
3257
3258     case MSG_DESTROY:
3259         dview_save_options (dview);
3260         dview_fini (dview);
3261         return MSG_HANDLED;
3262
3263     default:
3264         return widget_default_callback (w, sender, msg, parm, data);
3265     }
3266 }
3267
3268 /* --------------------------------------------------------------------------------------------- */
3269
3270 static void
3271 dview_mouse_callback (Widget *w, mouse_msg_t msg, mouse_event_t *event)
3272 {
3273     WDiff *dview = (WDiff *) w;
3274
3275     (void) event;
3276
3277     switch (msg)
3278     {
3279     case MSG_MOUSE_SCROLL_UP:
3280     case MSG_MOUSE_SCROLL_DOWN:
3281         if (msg == MSG_MOUSE_SCROLL_UP)
3282             dview->skip_rows -= 2;
3283         else
3284             dview->skip_rows += 2;
3285
3286         dview->search.last_accessed_num_line = dview->skip_rows;
3287         dview_update (dview);
3288         break;
3289
3290     default:
3291         break;
3292     }
3293 }
3294
3295 /* --------------------------------------------------------------------------------------------- */
3296
3297 static cb_ret_t
3298 dview_dialog_callback (Widget *w, Widget *sender, widget_msg_t msg, int parm, void *data)
3299 {
3300     WDiff *dview;
3301     WDialog *h = DIALOG (w);
3302
3303     switch (msg)
3304     {
3305     case MSG_ACTION:
3306         // Handle shortcuts.
3307
3308         /* Note: the buttonbar sends messages directly to the the WDiff, not to
3309          * here, which is why we can pass NULL in the following call. */
3310         return dview_execute_cmd (NULL, parm);
3311
3312     case MSG_VALIDATE:
3313         dview = (WDiff *) widget_find_by_type (CONST_WIDGET (h), dview_callback);
3314         // don't stop the dialog before final decision
3315         widget_set_state (w, WST_ACTIVE, TRUE);
3316         if (dview_ok_to_exit (dview))
3317             dlg_close (h);
3318         return MSG_HANDLED;
3319
3320     default:
3321         return dlg_default_callback (w, sender, msg, parm, data);
3322     }
3323 }
3324
3325 /* --------------------------------------------------------------------------------------------- */
3326
3327 static char *
3328 dview_get_title (const WDialog *h, size_t len)
3329 {
3330     const WDiff *dview;
3331     const char *modified = " (*) ";
3332     const char *notmodified = "     ";
3333     size_t len1;
3334     GString *title;
3335
3336     dview = (const WDiff *) widget_find_by_type (CONST_WIDGET (h), dview_callback);
3337     len1 = (len - str_term_width1 (_ ("Diff:")) - strlen (modified) - 3) / 2;
3338
3339     title = g_string_sized_new (len);
3340     g_string_append (title, _ ("Diff:"));
3341     g_string_append (title, dview->merged[DIFF_LEFT] ? modified : notmodified);
3342     g_string_append (title, str_term_trim (dview->label[DIFF_LEFT], len1));
3343     g_string_append (title, " | ");
3344     g_string_append (title, dview->merged[DIFF_RIGHT] ? modified : notmodified);
3345     g_string_append (title, str_term_trim (dview->label[DIFF_RIGHT], len1));
3346
3347     return g_string_free (title, FALSE);
3348 }
3349
3350 /* --------------------------------------------------------------------------------------------- */
3351
3352 static int
3353 diff_view (const char *file1, const char *file2, const char *label1, const char *label2)
3354 {
3355     int error;
3356     WDiff *dview;
3357     Widget *w;
3358     WDialog *dview_dlg;
3359     Widget *dw;
3360     WRect r;
3361     WGroup *g;
3362
3363     // Create dialog and widgets, put them on the dialog
3364     dview_dlg = dlg_create (FALSE, 0, 0, 1, 1, WPOS_FULLSCREEN, FALSE, NULL, dview_dialog_callback,
3365                             NULL, "[Diff Viewer]", NULL);
3366     dw = WIDGET (dview_dlg);
3367     widget_want_tab (dw, TRUE);
3368     r = dw->rect;
3369
3370     g = GROUP (dview_dlg);
3371
3372     dview = g_new0 (WDiff, 1);
3373     w = WIDGET (dview);
3374     r.lines--;
3375     widget_init (w, &r, dview_callback, dview_mouse_callback);
3376     w->options |= WOP_SELECTABLE;
3377     w->keymap = diff_map;
3378     group_add_widget_autopos (g, w, WPOS_KEEP_ALL, NULL);
3379
3380     w = WIDGET (buttonbar_new ());
3381     group_add_widget_autopos (g, w, w->pos_flags, NULL);
3382
3383     dview_dlg->get_title = dview_get_title;
3384
3385     error =
3386         dview_init (dview, "-a", file1, file2, label1, label2, DATA_SRC_MEM);  // XXX binary diff?
3387     if (error >= 0)
3388         error = redo_diff (dview);
3389     if (error >= 0)
3390     {
3391         dview->ndiff = error;
3392         dview_compute_areas (dview);
3393         error = 0;
3394     }
3395
3396     if (error == 0)
3397         dlg_run (dview_dlg);
3398
3399     if (error != 0 || widget_get_state (dw, WST_CLOSED))
3400         widget_destroy (dw);
3401
3402     return error == 0 ? 1 : 0;
3403 }
3404
3405 /*** public functions ****************************************************************************/
3406 /* --------------------------------------------------------------------------------------------- */
3407
3408 #define GET_FILE_AND_STAMP(n)                                                                      \
3409     do                                                                                             \
3410     {                                                                                              \
3411         use_copy##n = 0;                                                                           \
3412         real_file##n = file##n;                                                                    \
3413         if (!vfs_file_is_local (file##n))                                                          \
3414         {                                                                                          \
3415             real_file##n = mc_getlocalcopy (file##n);                                              \
3416             if (real_file##n != NULL)                                                              \
3417             {                                                                                      \
3418                 use_copy##n = 1;                                                                   \
3419                 if (mc_stat (real_file##n, &st##n) != 0)                                           \
3420                     use_copy##n = -1;                                                              \
3421             }                                                                                      \
3422         }                                                                                          \
3423     }                                                                                              \
3424     while (0)
3425
3426 #define UNGET_FILE(n)                                                                              \
3427     do                                                                                             \
3428     {                                                                                              \
3429         if (use_copy##n != 0)                                                                      \
3430         {                                                                                          \
3431             gboolean changed = FALSE;                                                              \
3432             if (use_copy##n > 0)                                                                   \
3433             {                                                                                      \
3434                 time_t mtime;                                                                      \
3435                 mtime = st##n.st_mtime;                                                            \
3436                 if (mc_stat (real_file##n, &st##n) == 0)                                           \
3437                     changed = (mtime != st##n.st_mtime);                                           \
3438             }                                                                                      \
3439             mc_ungetlocalcopy (file##n, real_file##n, changed);                                    \
3440             vfs_path_free (real_file##n, TRUE);                                                    \
3441         }                                                                                          \
3442     }                                                                                              \
3443     while (0)
3444
3445 gboolean
3446 dview_diff_cmd (const void *f0, const void *f1)
3447 {
3448     int rv = 0;
3449     vfs_path_t *file0 = NULL;
3450     vfs_path_t *file1 = NULL;
3451     gboolean is_dir0 = FALSE;
3452     gboolean is_dir1 = FALSE;
3453
3454     switch (mc_global.mc_run_mode)
3455     {
3456     case MC_RUN_FULL:
3457     {
3458         // run from panels
3459         const WPanel *panel0 = (const WPanel *) f0;
3460         const WPanel *panel1 = (const WPanel *) f1;
3461         const file_entry_t *fe0, *fe1;
3462
3463         fe0 = panel_current_entry (panel0);
3464         if (fe0 == NULL)
3465         {
3466             message (D_ERROR, MSG_ERROR, "%s", _ ("File name is empty!"));
3467             goto ret;
3468         }
3469
3470         file0 = vfs_path_append_new (panel0->cwd_vpath, fe0->fname->str, (char *) NULL);
3471         is_dir0 = S_ISDIR (fe0->st.st_mode);
3472         if (is_dir0)
3473         {
3474             message (D_ERROR, MSG_ERROR, _ ("\"%s\" is a directory"),
3475                      path_trunc (fe0->fname->str, 30));
3476             goto ret;
3477         }
3478
3479         fe1 = panel_current_entry (panel1);
3480         if (fe1 == NULL)
3481         {
3482             message (D_ERROR, MSG_ERROR, "%s", _ ("File name is empty!"));
3483             goto ret;
3484         }
3485         file1 = vfs_path_append_new (panel1->cwd_vpath, fe1->fname->str, (char *) NULL);
3486         is_dir1 = S_ISDIR (fe1->st.st_mode);
3487         if (is_dir1)
3488         {
3489             message (D_ERROR, MSG_ERROR, _ ("\"%s\" is a directory"),
3490                      path_trunc (fe1->fname->str, 30));
3491             goto ret;
3492         }
3493         break;
3494     }
3495
3496     case MC_RUN_DIFFVIEWER:
3497     {
3498         // run from command line
3499         const char *p0 = (const char *) f0;
3500         const char *p1 = (const char *) f1;
3501         struct stat st;
3502
3503         file0 = vfs_path_from_str (p0);
3504         if (mc_stat (file0, &st) == 0)
3505         {
3506             is_dir0 = S_ISDIR (st.st_mode);
3507             if (is_dir0)
3508             {
3509                 message (D_ERROR, MSG_ERROR, _ ("\"%s\" is a directory"), path_trunc (p0, 30));
3510                 goto ret;
3511             }
3512         }
3513         else
3514         {
3515             message (D_ERROR, MSG_ERROR, _ ("Cannot stat \"%s\"\n%s"), path_trunc (p0, 30),
3516                      unix_error_string (errno));
3517             goto ret;
3518         }
3519
3520         file1 = vfs_path_from_str (p1);
3521         if (mc_stat (file1, &st) == 0)
3522         {
3523             is_dir1 = S_ISDIR (st.st_mode);
3524             if (is_dir1)
3525             {
3526                 message (D_ERROR, MSG_ERROR, _ ("\"%s\" is a directory"), path_trunc (p1, 30));
3527                 goto ret;
3528             }
3529         }
3530         else
3531         {
3532             message (D_ERROR, MSG_ERROR, _ ("Cannot stat \"%s\"\n%s"), path_trunc (p1, 30),
3533                      unix_error_string (errno));
3534             goto ret;
3535         }
3536         break;
3537     }
3538
3539     default:
3540         // this should not happened
3541         message (D_ERROR, MSG_ERROR, _ ("Diff viewer: invalid mode"));
3542         return FALSE;
3543     }
3544
3545     if (rv == 0)
3546     {
3547         rv = -1;
3548         if (file0 != NULL && file1 != NULL)
3549         {
3550             int use_copy0, use_copy1;
3551             struct stat st0, st1;
3552             vfs_path_t *real_file0, *real_file1;
3553
3554             GET_FILE_AND_STAMP (0);
3555             GET_FILE_AND_STAMP (1);
3556
3557             if (real_file0 != NULL && real_file1 != NULL)
3558                 rv = diff_view (vfs_path_as_str (real_file0), vfs_path_as_str (real_file1),
3559                                 vfs_path_as_str (file0), vfs_path_as_str (file1));
3560
3561             UNGET_FILE (1);
3562             UNGET_FILE (0);
3563         }
3564     }
3565
3566     if (rv == 0)
3567         message (D_ERROR, MSG_ERROR, _ ("Two files are needed to compare"));
3568
3569 ret:
3570     vfs_path_free (file1, TRUE);
3571     vfs_path_free (file0, TRUE);
3572
3573     return (rv != 0);
3574 }
3575
3576 #undef GET_FILE_AND_STAMP
3577 #undef UNGET_FILE
3578
3579 /* --------------------------------------------------------------------------------------------- */