* fhandler.h (class fhandler_dev_clipboard): Remove member eof.

	* fhandler_clipboard.cc: Throughout remove handling of eof member.
	(fhandler_dev_clipboard::write): Handle EOF condition immediately,
	rather than pushing it erroneously to the next read call.  Rearrange
	code.  Fix bug in CF_UNICODETEXT case which potentially dropped single
	bytes at the end of the buffer.  Add comment.
	* strfuncs.cc (sys_cp_wcstombs): Allow returning non-NUL-terminated
	buffer if dst != NULL and len == (size_t) -1.  Extend leading comment
	to explain what's returned in more detail.

4 files changed, 87 insertions, 77 deletions

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 7ae793f3b..998be8dbd 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,15 @@
+2012-07-02  Corinna Vinschen  <corinna@vinschen.de>
+
+	* fhandler.h (class fhandler_dev_clipboard): Remove member eof.
+	* fhandler_clipboard.cc: Throughout remove handling of eof member.
+	(fhandler_dev_clipboard::write): Handle EOF condition immediately,
+	rather than pushing it erroneously to the next read call.  Rearrange
+	code.  Fix bug in CF_UNICODETEXT case which potentially dropped single
+	bytes at the end of the buffer.  Add comment.
+	* strfuncs.cc (sys_cp_wcstombs): Allow returning non-NUL-terminated
+	buffer if dst != NULL and len == (size_t) -1.  Extend leading comment
+	to explain what's returned in more detail.
+
 2012-07-02  Christopher Faylor  <me.cygwin2012@cgf.cx>
 
 	* fhandler_virtual.cc (fhandler_virtual::opendir): Eliminate duplicate
diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index 72f8d8429..9f30f5cc0 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -1721,7 +1721,6 @@ class fhandler_dev_clipboard: public fhandler_base
   _off64_t pos;
   void *membuffer;
   size_t msize;
-  bool eof;
  public:
   fhandler_dev_clipboard ();
   int is_windows () { return 1; }
diff --git a/winsup/cygwin/fhandler_clipboard.cc b/winsup/cygwin/fhandler_clipboard.cc
index 203af58bb..86f126c24 100644
--- a/winsup/cygwin/fhandler_clipboard.cc
+++ b/winsup/cygwin/fhandler_clipboard.cc
@@ -41,8 +41,7 @@ typedef struct
 } cygcb_t;
 
 fhandler_dev_clipboard::fhandler_dev_clipboard ()
-  : fhandler_base (), pos (0), membuffer (NULL), msize (0),
-  eof (true)
+  : fhandler_base (), pos (0), membuffer (NULL), msize (0)
 {
   /* FIXME: check for errors and loop until we can open the clipboard */
   OpenClipboard (NULL);
@@ -69,7 +68,6 @@ int
 fhandler_dev_clipboard::open (int flags, mode_t)
 {
   set_flags (flags | O_TEXT);
-  eof = false;
   pos = 0;
   if (membuffer)
     free (membuffer);
@@ -158,38 +156,28 @@ set_clipboard (const void *buf, size_t len)
 ssize_t __stdcall
 fhandler_dev_clipboard::write (const void *buf, size_t len)
 {
-  if (!eof)
+  /* write to our membuffer */
+  size_t cursize = msize;
+  void *tempbuffer = realloc (membuffer, cursize + len);
+  if (!tempbuffer)
     {
-      /* write to our membuffer */
-      size_t cursize = msize;
-      void *tempbuffer = realloc (membuffer, cursize + len);
-      if (!tempbuffer)
-	{
-	  debug_printf ("Couldn't realloc() clipboard buffer for write");
-	  return -1;
-	}
-      membuffer = tempbuffer;
-      msize = cursize + len;
-      memcpy ((unsigned char *) membuffer + cursize, buf, len);
-
-      /* now pass to windows */
-      if (set_clipboard (membuffer, msize))
-	{
-	  /* FIXME: membuffer is now out of sync with pos, but msize
-		    is used above */
-	  return -1;
-	}
-
-      pos = msize;
-
-      eof = false;
-      return len;
+      debug_printf ("Couldn't realloc() clipboard buffer for write");
+      return -1;
     }
-  else
+  membuffer = tempbuffer;
+  msize = cursize + len;
+  memcpy ((unsigned char *) membuffer + cursize, buf, len);
+
+  /* now pass to windows */
+  if (set_clipboard (membuffer, msize))
     {
-      /* FIXME: return 0 bytes written, file not open */
-      return 0;
+      /* FIXME: membuffer is now out of sync with pos, but msize
+		is used above */
+      return -1;
     }
+
+  pos = msize;
+  return len;
 }
 
 int __stdcall
@@ -230,66 +218,65 @@ void __stdcall
 fhandler_dev_clipboard::read (void *ptr, size_t& len)
 {
   HGLOBAL hglb;
-  size_t ret;
+  size_t ret = 0;
   UINT formatlist[2];
   int format;
-  size_t plen = len;
+  LPVOID cb_data;
 
-  len = 0;
-  if (eof)
-    return;
   if (!OpenClipboard (NULL))
-    return;
-  formatlist[0] = cygnativeformat;
-  formatlist[1] = CF_UNICODETEXT;
-  if ((format = GetPriorityClipboardFormat (formatlist, 2)) <= 0)
     {
-      CloseClipboard ();
+      len = 0;
       return;
     }
-  if (!(hglb = GetClipboardData (format)))
+  formatlist[0] = cygnativeformat;
+  formatlist[1] = CF_UNICODETEXT;
+  if ((format = GetPriorityClipboardFormat (formatlist, 2)) <= 0
+      || !(hglb = GetClipboardData (format))
+      || !(cb_data = GlobalLock (hglb)))
     {
       CloseClipboard ();
+      len = 0;
       return;
     }
   if (format == cygnativeformat)
     {
-      cygcb_t *clipbuf;
+      cygcb_t *clipbuf = (cygcb_t *) cb_data;
 
-      if (!(clipbuf = (cygcb_t *) GlobalLock (hglb)))
-	{
-	  CloseClipboard ();
-	  return;
+      if (pos < clipbuf->len)
+      	{
+	  ret = ((len > (clipbuf->len - pos)) ? (clipbuf->len - pos) : len);
+	  memcpy (ptr, clipbuf->data + pos , ret);
+	  pos += ret;
 	}
-      ret = ((plen > (clipbuf->len - pos)) ? (clipbuf->len - pos) : plen);
-      memcpy (ptr, clipbuf->data + pos , ret);
-      pos += ret;
-      if (pos + plen - ret >= clipbuf->len)
-	eof = true;
     }
   else
     {
-      int wret;
-      PWCHAR buf;
+      wchar_t *buf = (wchar_t *) cb_data;
 
-      if (!(buf = (PWCHAR) GlobalLock (hglb)))
+      size_t glen = GlobalSize (hglb) / sizeof (WCHAR) - 1;
+      if (pos < glen)
 	{
-	  CloseClipboard ();
-	  return;
+	  /* Comparing apples and oranges here, but the below loop could become
+	     extremly slow otherwise.  We rather return a few bytes less than
+	     possible instead of being even more slow than usual... */
+	  if (glen > pos + len)
+	    glen = pos + len;
+	  /* This loop is necessary because the number of bytes returned by
+	     sys_wcstombs does not indicate the number of wide chars used for
+	     it, so we could potentially drop wide chars. */
+	  while ((ret = sys_wcstombs (NULL, 0, buf + pos, glen - pos))
+		  != (size_t) -1
+		 && ret > len)
+	     --glen;
+	  if (ret == (size_t) -1)
+	    ret = 0;
+	  else
+	    {
+	      ret = sys_wcstombs ((char *) ptr, (size_t) -1,
+				  buf + pos, glen - pos);
+	      pos = glen;
+	    }
 	}
-      size_t glen = GlobalSize (hglb) / sizeof (WCHAR) - 1;
-      /* This loop is necessary because the number of bytes returned by
-	 sys_wcstombs does not indicate the number of wide chars used for
-	 it, so we could potentially drop wide chars. */
-      if (glen - pos > plen)
-	glen = pos + plen;
-      while ((wret = sys_wcstombs (NULL, 0, buf + pos, glen - pos)) != -1
-	     && (size_t) wret > plen)
-	--glen;
-      ret = sys_wcstombs ((char *) ptr, plen, buf + pos, glen - pos);
-      pos += ret;
-      if (pos + plen - ret >= wcslen (buf))
-	eof = true;
     }
   GlobalUnlock (hglb);
   CloseClipboard ();
@@ -316,7 +303,6 @@ fhandler_dev_clipboard::close ()
 {
   if (!have_execed)
     {
-      eof = true;
       pos = 0;
       if (membuffer)
 	{
@@ -333,7 +319,6 @@ fhandler_dev_clipboard::fixup_after_exec ()
 {
   if (!close_on_exec ())
     {
-      eof = false;
       pos = msize = 0;
       membuffer = NULL;
     }
diff --git a/winsup/cygwin/strfuncs.cc b/winsup/cygwin/strfuncs.cc
index 467f54e87..22ba4d619 100644
--- a/winsup/cygwin/strfuncs.cc
+++ b/winsup/cygwin/strfuncs.cc
@@ -393,9 +393,23 @@ __big5_mbtowc (struct _reent *r, wchar_t *pwc, const char *s, size_t n,
      sequence in by treating it as an UTF-8 char.  If that fails, the ASCII
      CAN was probably standalone and it gets just copied over as ASCII CAN.
 
-   - The functions always create 0-terminated results, no matter what.
-     If the result is truncated due to buffer size, it's a bug in Cygwin
-     and the buffer in the calling function should be raised. */
+   - Three cases have to be distinguished for the return value:
+
+     - dst == NULL; len is ignored, the return value is the number of bytes
+       required for the string without the trailing NUL, just like the return
+       value of the wcstombs function.
+
+     - dst != NULL, len == (size_t) -1; the return value is the size in bytes
+       of the destination string without the trailing NUL.  If the incoming
+       wide char string was not NUL-terminated, the target string won't be
+       NUL-terminated either.
+
+     - dst != NULL; len != (size_t) -1; the return value is the size in bytes
+       of the destination string without the trailing NUL.  The target string
+       will be NUL-terminated, no matter what.  If the result is truncated due
+       to buffer size, it's a bug in Cygwin and the buffer in the calling
+       function should be raised.
+*/
 size_t __stdcall
 sys_cp_wcstombs (wctomb_p f_wctomb, const char *charset, char *dst, size_t len,
 		 const wchar_t *src, size_t nwc)
@@ -473,7 +487,7 @@ sys_cp_wcstombs (wctomb_p f_wctomb, const char *charset, char *dst, size_t len,
       else
 	break;
     }
-  if (n && dst)
+  if (n && dst && len != (size_t) -1)
     {
       n = (n < len) ? n : len - 1;
       dst[n] = '\0';