(add_to_log): Pass 1 byte less to message_dolog.

[gnu-emacs] / src / w16select.c

diff --git a/src/w16select.c b/src/w16select.c
index e94a420d1a4b89e1265a4b8c620aa14222215672..674be37544e38b23e9c1a104d186eab1ddd7854f 100644 (file)
--- a/src/w16select.c
+++ b/src/w16select.c
@@ -77,11 +77,21 @@ static Lisp_Object Vnext_selection_coding_system;
 
 /* The segment address and the size of the buffer in low
    memory used to move data between us and WinOldAp module.  */
-
 static struct {
   unsigned long size;
   unsigned short rm_segment;
 } clipboard_xfer_buf_info;
+
+/* The last text we put into the clipboard.  This is used to prevent
+   passing back our own text from the clipboard, instead of using the
+   kill ring.  The former is undesirable because the clipboard data
+   could be MULEtilated by inappropriately chosen
+   (next-)selection-coding-system.  For this reason, we must store the
+   text *after* it was encoded/Unix-to-DOS-converted.  */
+static unsigned char *last_clipboard_text;
+
+/* The size of allocated storage for storing the clipboard data.  */
+static size_t clipboard_storage_size;
 \f
 /* Emulation of `__dpmi_int' and friends for DJGPP v1.x  */
 
@@ -291,6 +301,18 @@ set_clipboard_data (Format, Data, Size, Raw)
       _farnspokeb (buf_offset, '\0');
     }
 
+  /* Stash away the data we are about to put into the clipboard, so we
+     could later check inside get_clipboard_data whether the clipboard
+     still holds our data.  */
+  if (clipboard_storage_size < truelen)
+    {
+      clipboard_storage_size = truelen + 100;
+      last_clipboard_text =
+       (char *) xrealloc (last_clipboard_text, clipboard_storage_size);
+    }
+  if (last_clipboard_text)
+    dosmemget (xbuf_addr, truelen, last_clipboard_text);
+
   /* Calls Int 2Fh/AX=1703h with:
                     DX = WinOldAp-Supported Clipboard format
                      ES:BX = Pointer to data
@@ -307,6 +329,10 @@ set_clipboard_data (Format, Data, Size, Raw)
 
   free_xfer_buf ();
 
+  /* If the above failed, invalidate the local copy of the clipboard.  */
+  if (regs.x.ax == 0)
+    *last_clipboard_text = '\0';
+
   /* Zero means success, otherwise (1 or 2) it's an error.  */
   return regs.x.ax > 0 ? 0 : 1;
 }
@@ -343,10 +369,6 @@ get_clipboard_data (Format, Data, Size, Raw)
   __dpmi_regs regs;
   unsigned long xbuf_addr;
   unsigned char *dp = Data;
-  /* The last 32-byte aligned block of data.  See commentary below.  */
-  unsigned char *last_block = dp + ((Size & 0x1f)
-                                   ? (Size & 0x20)
-                                   : Size - 0x20);
 
   if (Format != CF_OEMTEXT)
     return 0;
@@ -370,6 +392,14 @@ get_clipboard_data (Format, Data, Size, Raw)
   __dpmi_int(0x2f, &regs);
   if (regs.x.ax != 0)
     {
+      unsigned char null_char = '\0';
+      unsigned long xbuf_beg = xbuf_addr;
+
+      /* If last_clipboard_text is NULL, we don't want to slow down
+        the next loop by an additional test.  */
+      register unsigned char *lcdp =
+       last_clipboard_text == NULL ? &null_char : last_clipboard_text;
+       
       /* Copy data from low memory, remove CR
         characters before LF if needed.  */
       _farsetsel (_dos_ds);
@@ -377,20 +407,33 @@ get_clipboard_data (Format, Data, Size, Raw)
        {
          register unsigned char c = _farnspeekb (xbuf_addr++);
 
+         if (*lcdp == c)
+           lcdp++;
+
          if ((*dp++ = c) == '\r' && !Raw && _farnspeekb (xbuf_addr) == '\n')
            {
              dp--;
              *dp++ = '\n';
              xbuf_addr++;
-             last_block--;     /* adjust the beginning of the last 32 bytes */
+             if (*lcdp == '\n')
+               lcdp++;
            }
          /* Windows reportedly rounds up the size of clipboard data
-            (passed in SIZE) to a multiple of 32.  We therefore bail
-            out when we see the first null character in the last 32-byte
-            block.  */
-         else if (c == '\0' && dp > last_block)
+            (passed in SIZE) to a multiple of 32, and removes trailing
+            spaces from each line without updating SIZE.  We therefore
+            bail out when we see the first null character.  */
+         else if (c == '\0')
            break;
        }
+
+      /* If the text in clipboard is identical to what we put there
+        last time set_clipboard_data was called, pretend there's no
+        data in the clipboard.  This is so we don't pass our own text
+        from the clipboard (which might be troublesome if the killed
+        text includes null characters).  */
+      if (last_clipboard_text &&
+         xbuf_addr - xbuf_beg == (long)(lcdp - last_clipboard_text))
+       dp = (unsigned char *)Data + 1;
     }
 
   free_xfer_buf ();
@@ -495,6 +538,8 @@ DEFUN ("w16-set-clipboard-data", Fw16_set_clipboard_data, Sw16_set_clipboard_dat
       dst = (unsigned char *) xmalloc (bufsize);
       encode_coding (&coding, src, dst, nbytes, bufsize);
       no_crlf_conversion = 1;
+      nbytes = coding.produced;
+      src = dst;
     }
 
   if (!open_clipboard ())