src/w16select.c

   1 /* 16-bit Windows Selection processing for emacs on MS-Windows
   2    Copyright (C) 1996, 1997, 2001, 2002, 2003, 2004,
   3                  2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software: you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation, either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 /* These functions work by using WinOldAp interface.  WinOldAp
  21    (WINOLDAP.MOD) is a Microsoft Windows extension supporting
  22    "old" (character-mode) application access to Dynamic Data Exchange,
  23    menus, and the Windows clipboard.  */
  24
  25 /* Written by Dale P. Smith <dpsm@en.com>  */
  26 /* Adapted to DJGPP by Eli Zaretskii <eliz@gnu.org>  */
  27
  28 #ifdef MSDOS
  29
  30 #include <config.h>
  31 #include <string.h>
  32 #include <dpmi.h>
  33 #include <go32.h>
  34 #include <sys/farptr.h>
  35 #include <setjmp.h>
  36 #include "lisp.h"
  37 #include "dispextern.h" /* frame.h seems to want this */
  38 #include "frame.h"      /* Need this to get the X window of selected_frame */
  39 #include "blockinput.h"
  40 #include "buffer.h"
  41 #include "character.h"
  42 #include "coding.h"
  43 #include "composite.h"
  44
  45 /* If ever some function outside this file will need to call any
  46    clipboard-related function, the following prototypes and constants
  47    should be put on a header file.  Right now, nobody else uses them.  */
  48
  49 #define CF_TEXT      0x01
  50 #define CF_BITMAP    0x02
  51 #define CF_METAFILE  0x03
  52 #define CF_SYLK      0x04
  53 #define CF_DIF       0x05
  54 #define CF_TIFF      0x06
  55 #define CF_OEMTEXT   0x07
  56 #define CF_DIBBITMAP 0x08
  57 #define CF_WINWRITE  0x80
  58 #define CF_DSPTEXT   0x81
  59 #define CF_DSPBITMAP 0x82
  60
  61 unsigned identify_winoldap_version (void);
  62 unsigned open_clipboard (void);
  63 unsigned empty_clipboard (void);
  64 unsigned set_clipboard_data (unsigned, void *, unsigned, int);
  65 unsigned get_clipboard_data_size (unsigned);
  66 unsigned get_clipboard_data (unsigned, void *, unsigned, int);
  67 unsigned close_clipboard (void);
  68 unsigned clipboard_compact (unsigned);
  69
  70 Lisp_Object QCLIPBOARD, QPRIMARY;
  71
  72 /* Coding system for communicating with other Windows programs via the
  73    clipboard.  */
  74 static Lisp_Object Vselection_coding_system;
  75
  76 /* Coding system for the next communicating with other Windows programs.  */
  77 static Lisp_Object Vnext_selection_coding_system;
  78
  79 /* The segment address and the size of the buffer in low
  80    memory used to move data between us and WinOldAp module.  */
  81 static struct {
  82   unsigned long size;
  83   unsigned short rm_segment;
  84 } clipboard_xfer_buf_info;
  85
  86 /* The last text we put into the clipboard.  This is used to prevent
  87    passing back our own text from the clipboard, instead of using the
  88    kill ring.  The former is undesirable because the clipboard data
  89    could be MULEtilated by inappropriately chosen
  90    (next-)selection-coding-system.  For this reason, we must store the
  91    text *after* it was encoded/Unix-to-DOS-converted.  */
  92 static unsigned char *last_clipboard_text;
  93
  94 /* The size of allocated storage for storing the clipboard data.  */
  95 static size_t clipboard_storage_size;
  96 \f
  97 /* C functions to access the Windows 3.1x clipboard from DOS apps.
  98
  99    The information was obtained from the Microsoft Knowledge Base,
 100    article Q67675 and can be found at:
 101    http://www.microsoft.com/kb/developr/win_dk/q67675.htm  */
 102
 103 /* See also Ralf Brown's Interrupt List.
 104
 105    I also seem to remember reading about this in Dr. Dobbs Journal a
 106    while ago, but if you knew my memory...  :-)
 107
 108    Dale P. Smith <dpsm@en.com> */
 109
 110 /* Return the WinOldAp support version, or 0x1700 if not supported.  */
 111 unsigned
 112 identify_winoldap_version ()
 113 {
 114   __dpmi_regs regs;
 115
 116   /* Calls Int 2Fh/AX=1700h
 117      Return Values   AX == 1700H: Clipboard functions not available
 118                         <> 1700H: AL = Major version number
 119                                   AH = Minor version number */
 120   regs.x.ax = 0x1700;
 121   __dpmi_int(0x2f, &regs);
 122   return regs.x.ax;
 123 }
 124
 125 /* Open the clipboard, return non-zero if successfull.  */
 126 unsigned
 127 open_clipboard ()
 128 {
 129   __dpmi_regs regs;
 130
 131   /* Is WINOLDAP supported?  */
 132   /* Kludge alert!!  If WinOldAp is not supported, we return a 0,
 133      which is the same as ``Clipboard already open''.  Currently,
 134      this is taken as an error by all the functions that use
 135      `open_clipboard', but if somebody someday will use that ``open''
 136      clipboard, they will have interesting time debugging it...  */
 137   if (identify_winoldap_version () == 0x1700)
 138     return 0;
 139
 140   /* Calls Int 2Fh/AX=1701h
 141      Return Values   AX == 0: Clipboard already open
 142                         <> 0: Clipboard opened */
 143   regs.x.ax = 0x1701;
 144   __dpmi_int(0x2f, &regs);
 145   return regs.x.ax;
 146 }
 147
 148 /* Empty clipboard, return non-zero if successfull.  */
 149 unsigned
 150 empty_clipboard ()
 151 {
 152   __dpmi_regs regs;
 153
 154   /* Calls Int 2Fh/AX=1702h
 155      Return Values   AX == 0: Error occurred
 156                         <> 0: OK, Clipboard emptied */
 157   regs.x.ax = 0x1702;
 158   __dpmi_int(0x2f, &regs);
 159   return regs.x.ax;
 160 }
 161
 162 /* Ensure we have a buffer in low memory with enough memory for data
 163    of size WANT_SIZE.  Return the linear address of the buffer.  */
 164 static unsigned long
 165 alloc_xfer_buf (want_size)
 166      unsigned want_size;
 167 {
 168   __dpmi_regs regs;
 169
 170   /* If the usual DJGPP transfer buffer is large enough, use that.  */
 171   if (want_size <= _go32_info_block.size_of_transfer_buffer)
 172     return __tb & 0xfffff;
 173
 174   /* Don't even try to allocate more than 1MB of memory: DOS cannot
 175      possibly handle that (it will overflow the BX register below).  */
 176   if (want_size > 0xfffff)
 177     return 0;
 178
 179   /* Need size rounded up to the nearest paragraph, and in
 180      paragraph units (1 paragraph = 16 bytes).  */
 181   clipboard_xfer_buf_info.size = (want_size + 15) >> 4;
 182
 183   /* The NT DPMI host crashes us if we free DOS memory via the
 184      DPMI service.  Work around by calling DOS allocate/free block.  */
 185   regs.h.ah = 0x48;
 186   regs.x.bx = clipboard_xfer_buf_info.size;
 187   __dpmi_int (0x21, &regs);
 188   if (regs.x.flags & 1)
 189     {
 190       clipboard_xfer_buf_info.size = 0;
 191       return 0;
 192     }
 193
 194   clipboard_xfer_buf_info.rm_segment = regs.x.ax;
 195   return (((int)clipboard_xfer_buf_info.rm_segment) << 4) & 0xfffff;
 196 }
 197
 198 /* Free our clipboard buffer.  We always free it after use, because
 199    keeping it leaves less free conventional memory for subprocesses.
 200    The clipboard buffer tends to be large in size, because for small
 201    clipboard data sizes we use the DJGPP transfer buffer.  */
 202 static void
 203 free_xfer_buf ()
 204 {
 205   /* If the size is 0, we used DJGPP transfer buffer, so don't free.  */
 206   if (clipboard_xfer_buf_info.size)
 207     {
 208       __dpmi_regs regs;
 209
 210       /* The NT DPMI host crashes us if we free DOS memory via
 211          the DPMI service.  Work around by calling DOS free block.  */
 212       regs.h.ah = 0x49;
 213       regs.x.es = clipboard_xfer_buf_info.rm_segment;
 214       __dpmi_int (0x21, &regs);
 215       clipboard_xfer_buf_info.size = 0;
 216     }
 217 }
 218
 219 /* Copy data into the clipboard, return zero if successfull.  */
 220 unsigned
 221 set_clipboard_data (Format, Data, Size, Raw)
 222      unsigned Format;
 223      void *Data;
 224      unsigned Size;
 225      int Raw;
 226 {
 227   __dpmi_regs regs;
 228   unsigned truelen;
 229   unsigned long xbuf_addr, buf_offset;
 230   unsigned char *dp = Data, *dstart = dp;
 231
 232   if (Format != CF_OEMTEXT)
 233     return 3;
 234
 235   /* need to know final size after '\r' chars are inserted (the
 236      standard CF_OEMTEXT clipboard format uses CRLF line endings,
 237      while Emacs uses just LF internally).  */
 238   truelen = Size + 1;           /* +1 for the terminating null */
 239
 240   if (!Raw)
 241     {
 242       /* avoid using strchr because it recomputes the length everytime */
 243       while ((dp = memchr (dp, '\n', Size - (dp - dstart))) != 0)
 244         {
 245           truelen++;
 246           dp++;
 247         }
 248     }
 249
 250   if (clipboard_compact (truelen) < truelen)
 251     return 1;
 252
 253   if ((xbuf_addr = alloc_xfer_buf (truelen)) == 0)
 254     return 1;
 255
 256   /* Move the buffer into the low memory, convert LF into CR-LF if needed.  */
 257   if (Raw)
 258     {
 259       dosmemput (Data, Size, xbuf_addr);
 260
 261       /* Terminate with a null, otherwise Windows does strange things
 262          when the text size is an integral multiple of 32 bytes. */
 263       _farpokeb (_dos_ds, xbuf_addr + Size, '\0');
 264     }
 265   else
 266     {
 267       dp = Data;
 268       buf_offset = xbuf_addr;
 269       _farsetsel (_dos_ds);
 270       while (Size--)
 271         {
 272           /* Don't allow them to put binary data into the clipboard, since
 273              it will cause yanked data to be truncated at the first null.  */
 274           if (*dp == '\0')
 275             return 2;
 276           if (*dp == '\n')
 277             _farnspokeb (buf_offset++, '\r');
 278           _farnspokeb (buf_offset++, *dp++);
 279         }
 280
 281       /* Terminate with a null, otherwise Windows does strange things
 282          when the text size is an integral multiple of 32 bytes. */
 283       _farnspokeb (buf_offset, '\0');
 284     }
 285
 286   /* Stash away the data we are about to put into the clipboard, so we
 287      could later check inside get_clipboard_data whether the clipboard
 288      still holds our data.  */
 289   if (clipboard_storage_size < truelen)
 290     {
 291       clipboard_storage_size = truelen + 100;
 292       last_clipboard_text =
 293         (char *) xrealloc (last_clipboard_text, clipboard_storage_size);
 294     }
 295   if (last_clipboard_text)
 296     dosmemget (xbuf_addr, truelen, last_clipboard_text);
 297
 298   /* Calls Int 2Fh/AX=1703h with:
 299                      DX = WinOldAp-Supported Clipboard format
 300                      ES:BX = Pointer to data
 301                      SI:CX = Size of data in bytes
 302      Return Values   AX == 0: Error occurred
 303                         <> 0: OK.  Data copied into the Clipboard.  */
 304   regs.x.ax = 0x1703;
 305   regs.x.dx = Format;
 306   regs.x.si = truelen >> 16;
 307   regs.x.cx = truelen & 0xffff;
 308   regs.x.es = xbuf_addr >> 4;
 309   regs.x.bx = xbuf_addr & 15;
 310   __dpmi_int(0x2f, &regs);
 311
 312   free_xfer_buf ();
 313
 314   /* If the above failed, invalidate the local copy of the clipboard.  */
 315   if (regs.x.ax == 0)
 316     *last_clipboard_text = '\0';
 317
 318   /* Zero means success, otherwise (1, 2, or 3) it's an error.  */
 319   return regs.x.ax > 0 ? 0 : 3;
 320 }
 321
 322 /* Return the size of the clipboard data of format FORMAT.  */
 323 unsigned
 324 get_clipboard_data_size (Format)
 325      unsigned Format;
 326 {
 327   __dpmi_regs regs;
 328
 329   /* Calls Int 2Fh/AX=1704h with:
 330                      DX = WinOldAp-Supported Clipboard format
 331      Return Values   DX:AX == Size of the data in bytes, including any
 332                               headers.
 333                            == 0 If data in this format is not in
 334                            the clipboard.  */
 335   regs.x.ax = 0x1704;
 336   regs.x.dx = Format;
 337   __dpmi_int(0x2f, &regs);
 338   return ( (((unsigned)regs.x.dx) << 16) | regs.x.ax);
 339 }
 340
 341 /* Get clipboard data, return its length.
 342    Warning: this doesn't check whether DATA has enough space to hold
 343    SIZE bytes.  */
 344 unsigned
 345 get_clipboard_data (Format, Data, Size, Raw)
 346      unsigned Format;
 347      void *Data;
 348      unsigned Size;
 349      int Raw;
 350 {
 351   __dpmi_regs regs;
 352   unsigned long xbuf_addr;
 353   unsigned char *dp = Data;
 354
 355   if (Format != CF_OEMTEXT)
 356     return 0;
 357
 358   if (Size == 0)
 359     return 0;
 360
 361   if ((xbuf_addr = alloc_xfer_buf (Size)) == 0)
 362     return 0;
 363
 364   /* Calls Int 2Fh/AX=1705h with:
 365                      DX = WinOldAp-Supported Clipboard format
 366                      ES:BX = Pointer to data buffer to hold data
 367      Return Values   AX == 0: Error occurred (or data in this format is not
 368                               in the clipboard)
 369                         <> 0: OK  */
 370   regs.x.ax = 0x1705;
 371   regs.x.dx = Format;
 372   regs.x.es = xbuf_addr >> 4;
 373   regs.x.bx = xbuf_addr & 15;
 374   __dpmi_int(0x2f, &regs);
 375   if (regs.x.ax != 0)
 376     {
 377       unsigned char null_char = '\0';
 378       unsigned long xbuf_beg = xbuf_addr;
 379
 380       /* If last_clipboard_text is NULL, we don't want to slow down
 381          the next loop by an additional test.  */
 382       register unsigned char *lcdp =
 383         last_clipboard_text == NULL ? &null_char : last_clipboard_text;
 384
 385       /* Copy data from low memory, remove CR
 386          characters before LF if needed.  */
 387       _farsetsel (_dos_ds);
 388       while (Size--)
 389         {
 390           register unsigned char c = _farnspeekb (xbuf_addr++);
 391
 392           if (*lcdp == c)
 393             lcdp++;
 394
 395           if ((*dp++ = c) == '\r' && !Raw && _farnspeekb (xbuf_addr) == '\n')
 396             {
 397               dp--;
 398               *dp++ = '\n';
 399               xbuf_addr++;
 400               if (*lcdp == '\n')
 401                 lcdp++;
 402             }
 403           /* Windows reportedly rounds up the size of clipboard data
 404              (passed in SIZE) to a multiple of 32, and removes trailing
 405              spaces from each line without updating SIZE.  We therefore
 406              bail out when we see the first null character.  */
 407           else if (c == '\0')
 408             break;
 409         }
 410
 411       /* If the text in clipboard is identical to what we put there
 412          last time set_clipboard_data was called, pretend there's no
 413          data in the clipboard.  This is so we don't pass our own text
 414          from the clipboard (which might be troublesome if the killed
 415          text includes null characters).  */
 416       if (last_clipboard_text &&
 417           xbuf_addr - xbuf_beg == (long)(lcdp - last_clipboard_text))
 418         dp = (unsigned char *)Data + 1;
 419     }
 420
 421   free_xfer_buf ();
 422
 423   return (unsigned) (dp - (unsigned char *)Data - 1);
 424 }
 425
 426 /* Close clipboard, return non-zero if successfull.  */
 427 unsigned
 428 close_clipboard ()
 429 {
 430   __dpmi_regs regs;
 431
 432   /* Calls Int 2Fh/AX=1708h
 433      Return Values   AX == 0: Error occurred
 434                         <> 0: OK */
 435   regs.x.ax = 0x1708;
 436   __dpmi_int(0x2f, &regs);
 437   return regs.x.ax;
 438 }
 439
 440 /* Compact clipboard data so that at least SIZE bytes is available.  */
 441 unsigned
 442 clipboard_compact (Size)
 443      unsigned Size;
 444 {
 445   __dpmi_regs regs;
 446
 447   /* Calls Int 2Fh/AX=1709H with:
 448                      SI:CX = Desired memory size in bytes.
 449      Return Values   DX:AX == Number of bytes of largest block of free memory.
 450                            == 0 if error or no memory  */
 451   regs.x.ax = 0x1709;
 452   regs.x.si = Size >> 16;
 453   regs.x.cx = Size & 0xffff;
 454   __dpmi_int(0x2f, &regs);
 455   return ((unsigned)regs.x.dx << 16) | regs.x.ax;
 456 }
 457 \f
 458 static char no_mem_msg[] =
 459   "(Not enough DOS memory to put saved text into clipboard.)";
 460 static char binary_msg[] =
 461   "(Binary characters in saved text; clipboard data not set.)";
 462 static char system_error_msg[] =
 463   "(Clipboard interface failure; clipboard data not set.)";
 464
 465 DEFUN ("w16-set-clipboard-data", Fw16_set_clipboard_data, Sw16_set_clipboard_data, 1, 2, 0,
 466        doc: /* This sets the clipboard data to the given text.  */)
 467      (string, frame)
 468      Lisp_Object string, frame;
 469 {
 470   unsigned ok = 1, put_status = 0;
 471   int nbytes, charset_info, no_crlf_conversion;
 472   unsigned char *src, *dst = NULL;
 473
 474   CHECK_STRING (string);
 475
 476   if (NILP (frame))
 477     frame = Fselected_frame ();
 478
 479   CHECK_LIVE_FRAME (frame);
 480   if ( !FRAME_MSDOS_P (XFRAME (frame)))
 481     goto done;
 482
 483   BLOCK_INPUT;
 484
 485   if (!open_clipboard ())
 486     goto error;
 487
 488   nbytes = SBYTES (string);
 489   src = SDATA (string);
 490
 491   /* Do we need to encode this text?  */
 492   for (dst = src; dst < src + nbytes; dst++)
 493     {
 494       if (*dst == '\0' || *dst >= 0x80)
 495         break;
 496     }
 497   if (dst >= src + nbytes)
 498     {
 499       /* No multibyte characters in text.  We need not encode it, but we
 500          will have to convert it to DOS CR-LF style.  */
 501       no_crlf_conversion = 0;
 502       Vlast_coding_system_used = Qraw_text;
 503       dst = NULL;       /* so we don't try to free a random pointer */
 504     }
 505   else
 506     {
 507       /* We must encode contents of STRING according to what
 508          clipboard-coding-system specifies.  */
 509       int bufsize;
 510       struct coding_system coding;
 511       unsigned char *htext2;
 512       Lisp_Object coding_system =
 513         NILP (Vnext_selection_coding_system) ?
 514         Vselection_coding_system : Vnext_selection_coding_system;
 515
 516       setup_coding_system (Fcheck_coding_system (coding_system), &coding);
 517       coding.dst_bytes = nbytes * 4;
 518       coding.destination = (unsigned char *) xmalloc (coding.dst_bytes);
 519       Vnext_selection_coding_system = Qnil;
 520       coding.mode |= CODING_MODE_LAST_BLOCK;
 521       dst = coding.destination;
 522       encode_coding_object (&coding, string, 0, 0,
 523                             SCHARS (string), nbytes, Qnil);
 524       no_crlf_conversion = 1;
 525       nbytes = coding.produced;
 526       Vlast_coding_system_used = CODING_ID_NAME (coding.id);
 527       src = dst;
 528     }
 529
 530   ok = empty_clipboard ()
 531     && ((put_status
 532          = set_clipboard_data (CF_OEMTEXT, src, nbytes, no_crlf_conversion))
 533         == 0);
 534
 535   if (!no_crlf_conversion)
 536   close_clipboard ();
 537
 538   if (ok) goto unblock;
 539
 540  error:
 541
 542   ok = 0;
 543
 544  unblock:
 545   xfree (dst);
 546   UNBLOCK_INPUT;
 547
 548   /* Notify user if the text is too large to fit into DOS memory.
 549      (This will happen somewhere after 600K bytes (470K in DJGPP v1.x),
 550      depending on user system configuration.)  If we just silently
 551      fail the function, people might wonder why their text sometimes
 552      doesn't make it to the clipboard.  */
 553   if (put_status)
 554     {
 555       switch (put_status)
 556         {
 557           case 1:
 558             message2 (no_mem_msg, sizeof (no_mem_msg) - 1, 0);
 559             break;
 560           case 2:
 561             message2 (binary_msg, sizeof (binary_msg) - 1, 0);
 562             break;
 563           case 3:
 564             message2 (system_error_msg, sizeof (system_error_msg) - 1, 0);
 565             break;
 566         }
 567       sit_for (make_number (2), 0, 2);
 568     }
 569
 570  done:
 571
 572   return (ok && put_status == 0 ? string : Qnil);
 573 }
 574
 575 DEFUN ("w16-get-clipboard-data", Fw16_get_clipboard_data, Sw16_get_clipboard_data, 0, 1, 0,
 576        doc: /* This gets the clipboard data in text format.  */)
 577      (frame)
 578      Lisp_Object frame;
 579 {
 580   unsigned data_size, truelen;
 581   unsigned char *htext = NULL;
 582   Lisp_Object ret = Qnil;
 583   int no_crlf_conversion, require_decoding = 0;
 584
 585   if (NILP (frame))
 586     frame = Fselected_frame ();
 587
 588   CHECK_LIVE_FRAME (frame);
 589   if ( !FRAME_MSDOS_P (XFRAME (frame)))
 590     goto done;
 591
 592   BLOCK_INPUT;
 593
 594   if (!open_clipboard ())
 595     goto unblock;
 596
 597   if ((data_size = get_clipboard_data_size (CF_OEMTEXT)) == 0 ||
 598       (htext = (unsigned char *)xmalloc (data_size)) == 0)
 599     goto closeclip;
 600
 601   /* need to know final size after '\r' chars are removed because
 602      we can't change the string size manually, and doing an extra
 603      copy is silly */
 604   if ((truelen = get_clipboard_data (CF_OEMTEXT, htext, data_size, 0)) == 0)
 605     goto closeclip;
 606
 607   /* Do we need to decode it?  */
 608   {
 609     /* If the clipboard data contains any 8-bit Latin-1 code, we
 610        need to decode it.  */
 611     int i;
 612
 613     for (i = 0; i < truelen; i++)
 614       {
 615         if (htext[i] >= 0x80)
 616           {
 617             require_decoding = 1;
 618             break;
 619           }
 620       }
 621   }
 622   if (require_decoding)
 623     {
 624       int bufsize;
 625       unsigned char *buf;
 626       struct coding_system coding;
 627       Lisp_Object coding_system = Vnext_selection_coding_system;
 628
 629       truelen = get_clipboard_data (CF_OEMTEXT, htext, data_size, 1);
 630       if (NILP (coding_system))
 631         coding_system = Vselection_coding_system;
 632       setup_coding_system (Fcheck_coding_system (coding_system), &coding);
 633       coding.source = htext;
 634       coding.mode |= CODING_MODE_LAST_BLOCK;
 635       /* We explicitly disable composition handling because selection
 636          data should not contain any composition sequence.  */
 637       coding.mode &= CODING_ANNOTATION_MASK;
 638       decode_coding_object (&coding, Qnil, 0, 0, truelen, truelen, Qt);
 639       ret = coding.dst_object;
 640       Vlast_coding_system_used = CODING_ID_NAME (coding.id);
 641     }
 642   else
 643     {
 644       ret = make_unibyte_string ((char *) htext, truelen);
 645       Vlast_coding_system_used = Qraw_text;
 646     }
 647
 648   xfree (htext);
 649   Vnext_selection_coding_system = Qnil;
 650
 651  closeclip:
 652   close_clipboard ();
 653
 654  unblock:
 655   UNBLOCK_INPUT;
 656
 657  done:
 658
 659   return (ret);
 660 }
 661
 662 /* Support checking for a clipboard selection. */
 663
 664 DEFUN ("x-selection-exists-p", Fx_selection_exists_p, Sx_selection_exists_p,
 665        0, 1, 0,
 666        doc: /* Whether there is an owner for the given X Selection.
 667 The arg should be the name of the selection in question, typically one of
 668 the symbols `PRIMARY', `SECONDARY', or `CLIPBOARD'.
 669 \(Those are literal upper-case symbol names, since that's what X expects.)
 670 For convenience, the symbol nil is the same as `PRIMARY',
 671 and t is the same as `SECONDARY'.  */)
 672      (selection)
 673      Lisp_Object selection;
 674 {
 675   CHECK_SYMBOL (selection);
 676
 677   /* Return nil for SECONDARY selection.  For PRIMARY (or nil)
 678      selection, check if there is some text on the kill-ring;
 679      for CLIPBOARD, check if the clipboard currently has valid
 680      text format contents.
 681
 682      The test for killed text on the kill-ring emulates the Emacs
 683      behavior on X, where killed text is also put into X selection
 684      by the X interface code.  (On MSDOS, killed text is only put
 685      into the clipboard if we run under Windows, so we cannot check
 686      the clipboard alone.)  */
 687   if ((EQ (selection, Qnil) || EQ (selection, QPRIMARY))
 688       && ! NILP (Fsymbol_value (Fintern_soft (build_string ("kill-ring"),
 689                                               Qnil))))
 690     return Qt;
 691
 692   if (EQ (selection, QCLIPBOARD))
 693     {
 694       Lisp_Object val = Qnil;
 695
 696       if (open_clipboard ())
 697         {
 698           if (get_clipboard_data_size (CF_OEMTEXT))
 699             val = Qt;
 700           close_clipboard ();
 701         }
 702       return val;
 703     }
 704   return Qnil;
 705 }
 706
 707 void
 708 syms_of_win16select ()
 709 {
 710   defsubr (&Sw16_set_clipboard_data);
 711   defsubr (&Sw16_get_clipboard_data);
 712   defsubr (&Sx_selection_exists_p);
 713
 714   DEFVAR_LISP ("selection-coding-system", &Vselection_coding_system,
 715                doc: /* Coding system for communicating with other X clients.
 716 When sending or receiving text via cut_buffer, selection, and clipboard,
 717 the text is encoded or decoded by this coding system.
 718 The default value is `iso-latin-1-dos'.  */);
 719   Vselection_coding_system = intern ("iso-latin-1-dos");
 720
 721   DEFVAR_LISP ("next-selection-coding-system", &Vnext_selection_coding_system,
 722                doc: /* Coding system for the next communication with other X clients.
 723 Usually, `selection-coding-system' is used for communicating with
 724 other X clients.  But, if this variable is set, it is used for the
 725 next communication only.  After the communication, this variable is
 726 set to nil.  */);
 727   Vnext_selection_coding_system = Qnil;
 728
 729   QPRIMARY   = intern ("PRIMARY");      staticpro (&QPRIMARY);
 730   QCLIPBOARD = intern ("CLIPBOARD");    staticpro (&QCLIPBOARD);
 731 }
 732
 733 #endif /* MSDOS */
 734
 735 /* arch-tag: 085a22c8-7324-436e-a6da-102464ce95d8
 736    (do not change this comment) */