patch 8.1.2094: the fileio.c file is too bigv8.1.2094

Problem:    The fileio.c file is too big.
Solution:   Move buf_write() to bufwrite.c. (Yegappan Lakshmanan,
            closes #4990)

1 files changed, 2559 insertions, 0 deletions

diff --git a/src/bufwrite.c b/src/bufwrite.c
new file mode 100644
index 0000000000..13091a336e
--- /dev/null
+++ b/src/bufwrite.c
@@ -0,0 +1,2559 @@
+/* vi:set ts=8 sts=4 sw=4 noet:
+ *
+ * VIM - Vi IMproved	by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ * See README.txt for an overview of the Vim source code.
+ */
+
+/*
+ * bufwrite.c: functions for writing a buffer
+ */
+
+#include "vim.h"
+
+#if defined(HAVE_UTIME) && defined(HAVE_UTIME_H)
+# include <utime.h>		// for struct utimbuf
+#endif
+
+#define SMALLBUFSIZE	256	// size of emergency write buffer
+
+/*
+ * Structure to pass arguments from buf_write() to buf_write_bytes().
+ */
+struct bw_info
+{
+    int		bw_fd;		// file descriptor
+    char_u	*bw_buf;	// buffer with data to be written
+    int		bw_len;		// length of data
+    int		bw_flags;	// FIO_ flags
+#ifdef FEAT_CRYPT
+    buf_T	*bw_buffer;	// buffer being written
+#endif
+    char_u	bw_rest[CONV_RESTLEN]; // not converted bytes
+    int		bw_restlen;	// nr of bytes in bw_rest[]
+    int		bw_first;	// first write call
+    char_u	*bw_conv_buf;	// buffer for writing converted chars
+    size_t	bw_conv_buflen; // size of bw_conv_buf
+    int		bw_conv_error;	// set for conversion error
+    linenr_T	bw_conv_error_lnum;  // first line with error or zero
+    linenr_T	bw_start_lnum;  // line number at start of buffer
+#ifdef USE_ICONV
+    iconv_t	bw_iconv_fd;	// descriptor for iconv() or -1
+#endif
+};
+
+/*
+ * Convert a Unicode character to bytes.
+ * Return TRUE for an error, FALSE when it's OK.
+ */
+    static int
+ucs2bytes(
+    unsigned	c,		// in: character
+    char_u	**pp,		// in/out: pointer to result
+    int		flags)		// FIO_ flags
+{
+    char_u	*p = *pp;
+    int		error = FALSE;
+    int		cc;
+
+
+    if (flags & FIO_UCS4)
+    {
+	if (flags & FIO_ENDIAN_L)
+	{
+	    *p++ = c;
+	    *p++ = (c >> 8);
+	    *p++ = (c >> 16);
+	    *p++ = (c >> 24);
+	}
+	else
+	{
+	    *p++ = (c >> 24);
+	    *p++ = (c >> 16);
+	    *p++ = (c >> 8);
+	    *p++ = c;
+	}
+    }
+    else if (flags & (FIO_UCS2 | FIO_UTF16))
+    {
+	if (c >= 0x10000)
+	{
+	    if (flags & FIO_UTF16)
+	    {
+		// Make two words, ten bits of the character in each.  First
+		// word is 0xd800 - 0xdbff, second one 0xdc00 - 0xdfff
+		c -= 0x10000;
+		if (c >= 0x100000)
+		    error = TRUE;
+		cc = ((c >> 10) & 0x3ff) + 0xd800;
+		if (flags & FIO_ENDIAN_L)
+		{
+		    *p++ = cc;
+		    *p++ = ((unsigned)cc >> 8);
+		}
+		else
+		{
+		    *p++ = ((unsigned)cc >> 8);
+		    *p++ = cc;
+		}
+		c = (c & 0x3ff) + 0xdc00;
+	    }
+	    else
+		error = TRUE;
+	}
+	if (flags & FIO_ENDIAN_L)
+	{
+	    *p++ = c;
+	    *p++ = (c >> 8);
+	}
+	else
+	{
+	    *p++ = (c >> 8);
+	    *p++ = c;
+	}
+    }
+    else    // Latin1
+    {
+	if (c >= 0x100)
+	{
+	    error = TRUE;
+	    *p++ = 0xBF;
+	}
+	else
+	    *p++ = c;
+    }
+
+    *pp = p;
+    return error;
+}
+
+/*
+ * Call write() to write a number of bytes to the file.
+ * Handles encryption and 'encoding' conversion.
+ *
+ * Return FAIL for failure, OK otherwise.
+ */
+    static int
+buf_write_bytes(struct bw_info *ip)
+{
+    int		wlen;
+    char_u	*buf = ip->bw_buf;	// data to write
+    int		len = ip->bw_len;	// length of data
+    int		flags = ip->bw_flags;	// extra flags
+
+    // Skip conversion when writing the crypt magic number or the BOM.
+    if (!(flags & FIO_NOCONVERT))
+    {
+	char_u		*p;
+	unsigned	c;
+	int		n;
+
+	if (flags & FIO_UTF8)
+	{
+	    // Convert latin1 in the buffer to UTF-8 in the file.
+	    p = ip->bw_conv_buf;	// translate to buffer
+	    for (wlen = 0; wlen < len; ++wlen)
+		p += utf_char2bytes(buf[wlen], p);
+	    buf = ip->bw_conv_buf;
+	    len = (int)(p - ip->bw_conv_buf);
+	}
+	else if (flags & (FIO_UCS4 | FIO_UTF16 | FIO_UCS2 | FIO_LATIN1))
+	{
+	    // Convert UTF-8 bytes in the buffer to UCS-2, UCS-4, UTF-16 or
+	    // Latin1 chars in the file.
+	    if (flags & FIO_LATIN1)
+		p = buf;	// translate in-place (can only get shorter)
+	    else
+		p = ip->bw_conv_buf;	// translate to buffer
+	    for (wlen = 0; wlen < len; wlen += n)
+	    {
+		if (wlen == 0 && ip->bw_restlen != 0)
+		{
+		    int		l;
+
+		    // Use remainder of previous call.  Append the start of
+		    // buf[] to get a full sequence.  Might still be too
+		    // short!
+		    l = CONV_RESTLEN - ip->bw_restlen;
+		    if (l > len)
+			l = len;
+		    mch_memmove(ip->bw_rest + ip->bw_restlen, buf, (size_t)l);
+		    n = utf_ptr2len_len(ip->bw_rest, ip->bw_restlen + l);
+		    if (n > ip->bw_restlen + len)
+		    {
+			// We have an incomplete byte sequence at the end to
+			// be written.  We can't convert it without the
+			// remaining bytes.  Keep them for the next call.
+			if (ip->bw_restlen + len > CONV_RESTLEN)
+			    return FAIL;
+			ip->bw_restlen += len;
+			break;
+		    }
+		    if (n > 1)
+			c = utf_ptr2char(ip->bw_rest);
+		    else
+			c = ip->bw_rest[0];
+		    if (n >= ip->bw_restlen)
+		    {
+			n -= ip->bw_restlen;
+			ip->bw_restlen = 0;
+		    }
+		    else
+		    {
+			ip->bw_restlen -= n;
+			mch_memmove(ip->bw_rest, ip->bw_rest + n,
+						      (size_t)ip->bw_restlen);
+			n = 0;
+		    }
+		}
+		else
+		{
+		    n = utf_ptr2len_len(buf + wlen, len - wlen);
+		    if (n > len - wlen)
+		    {
+			// We have an incomplete byte sequence at the end to
+			// be written.  We can't convert it without the
+			// remaining bytes.  Keep them for the next call.
+			if (len - wlen > CONV_RESTLEN)
+			    return FAIL;
+			ip->bw_restlen = len - wlen;
+			mch_memmove(ip->bw_rest, buf + wlen,
+						      (size_t)ip->bw_restlen);
+			break;
+		    }
+		    if (n > 1)
+			c = utf_ptr2char(buf + wlen);
+		    else
+			c = buf[wlen];
+		}
+
+		if (ucs2bytes(c, &p, flags) && !ip->bw_conv_error)
+		{
+		    ip->bw_conv_error = TRUE;
+		    ip->bw_conv_error_lnum = ip->bw_start_lnum;
+		}
+		if (c == NL)
+		    ++ip->bw_start_lnum;
+	    }
+	    if (flags & FIO_LATIN1)
+		len = (int)(p - buf);
+	    else
+	    {
+		buf = ip->bw_conv_buf;
+		len = (int)(p - ip->bw_conv_buf);
+	    }
+	}
+
+#ifdef MSWIN
+	else if (flags & FIO_CODEPAGE)
+	{
+	    // Convert UTF-8 or codepage to UCS-2 and then to MS-Windows
+	    // codepage.
+	    char_u	*from;
+	    size_t	fromlen;
+	    char_u	*to;
+	    int		u8c;
+	    BOOL	bad = FALSE;
+	    int		needed;
+
+	    if (ip->bw_restlen > 0)
+	    {
+		// Need to concatenate the remainder of the previous call and
+		// the bytes of the current call.  Use the end of the
+		// conversion buffer for this.
+		fromlen = len + ip->bw_restlen;
+		from = ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
+		mch_memmove(from, ip->bw_rest, (size_t)ip->bw_restlen);
+		mch_memmove(from + ip->bw_restlen, buf, (size_t)len);
+	    }
+	    else
+	    {
+		from = buf;
+		fromlen = len;
+	    }
+
+	    to = ip->bw_conv_buf;
+	    if (enc_utf8)
+	    {
+		// Convert from UTF-8 to UCS-2, to the start of the buffer.
+		// The buffer has been allocated to be big enough.
+		while (fromlen > 0)
+		{
+		    n = (int)utf_ptr2len_len(from, (int)fromlen);
+		    if (n > (int)fromlen)	// incomplete byte sequence
+			break;
+		    u8c = utf_ptr2char(from);
+		    *to++ = (u8c & 0xff);
+		    *to++ = (u8c >> 8);
+		    fromlen -= n;
+		    from += n;
+		}
+
+		// Copy remainder to ip->bw_rest[] to be used for the next
+		// call.
+		if (fromlen > CONV_RESTLEN)
+		{
+		    // weird overlong sequence
+		    ip->bw_conv_error = TRUE;
+		    return FAIL;
+		}
+		mch_memmove(ip->bw_rest, from, fromlen);
+		ip->bw_restlen = (int)fromlen;
+	    }
+	    else
+	    {
+		// Convert from enc_codepage to UCS-2, to the start of the
+		// buffer.  The buffer has been allocated to be big enough.
+		ip->bw_restlen = 0;
+		needed = MultiByteToWideChar(enc_codepage,
+			     MB_ERR_INVALID_CHARS, (LPCSTR)from, (int)fromlen,
+								     NULL, 0);
+		if (needed == 0)
+		{
+		    // When conversion fails there may be a trailing byte.
+		    needed = MultiByteToWideChar(enc_codepage,
+			 MB_ERR_INVALID_CHARS, (LPCSTR)from, (int)fromlen - 1,
+								     NULL, 0);
+		    if (needed == 0)
+		    {
+			// Conversion doesn't work.
+			ip->bw_conv_error = TRUE;
+			return FAIL;
+		    }
+		    // Save the trailing byte for the next call.
+		    ip->bw_rest[0] = from[fromlen - 1];
+		    ip->bw_restlen = 1;
+		}
+		needed = MultiByteToWideChar(enc_codepage, MB_ERR_INVALID_CHARS,
+				(LPCSTR)from, (int)(fromlen - ip->bw_restlen),
+							  (LPWSTR)to, needed);
+		if (needed == 0)
+		{
+		    // Safety check: Conversion doesn't work.
+		    ip->bw_conv_error = TRUE;
+		    return FAIL;
+		}
+		to += needed * 2;
+	    }
+
+	    fromlen = to - ip->bw_conv_buf;
+	    buf = to;
+# ifdef CP_UTF8	// VC 4.1 doesn't define CP_UTF8
+	    if (FIO_GET_CP(flags) == CP_UTF8)
+	    {
+		// Convert from UCS-2 to UTF-8, using the remainder of the
+		// conversion buffer.  Fails when out of space.
+		for (from = ip->bw_conv_buf; fromlen > 1; fromlen -= 2)
+		{
+		    u8c = *from++;
+		    u8c += (*from++ << 8);
+		    to += utf_char2bytes(u8c, to);
+		    if (to + 6 >= ip->bw_conv_buf + ip->bw_conv_buflen)
+		    {
+			ip->bw_conv_error = TRUE;
+			return FAIL;
+		    }
+		}
+		len = (int)(to - buf);
+	    }
+	    else
+# endif
+	    {
+		// Convert from UCS-2 to the codepage, using the remainder of
+		// the conversion buffer.  If the conversion uses the default
+		// character "0", the data doesn't fit in this encoding, so
+		// fail.
+		len = WideCharToMultiByte(FIO_GET_CP(flags), 0,
+			(LPCWSTR)ip->bw_conv_buf, (int)fromlen / sizeof(WCHAR),
+			(LPSTR)to, (int)(ip->bw_conv_buflen - fromlen), 0,
+									&bad);
+		if (bad)
+		{
+		    ip->bw_conv_error = TRUE;
+		    return FAIL;
+		}
+	    }
+	}
+#endif
+
+#ifdef MACOS_CONVERT
+	else if (flags & FIO_MACROMAN)
+	{
+	    // Convert UTF-8 or latin1 to Apple MacRoman.
+	    char_u	*from;
+	    size_t	fromlen;
+
+	    if (ip->bw_restlen > 0)
+	    {
+		// Need to concatenate the remainder of the previous call and
+		// the bytes of the current call.  Use the end of the
+		// conversion buffer for this.
+		fromlen = len + ip->bw_restlen;
+		from = ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
+		mch_memmove(from, ip->bw_rest, (size_t)ip->bw_restlen);
+		mch_memmove(from + ip->bw_restlen, buf, (size_t)len);
+	    }
+	    else
+	    {
+		from = buf;
+		fromlen = len;
+	    }
+
+	    if (enc2macroman(from, fromlen,
+			ip->bw_conv_buf, &len, ip->bw_conv_buflen,
+			ip->bw_rest, &ip->bw_restlen) == FAIL)
+	    {
+		ip->bw_conv_error = TRUE;
+		return FAIL;
+	    }
+	    buf = ip->bw_conv_buf;
+	}
+#endif
+
+#ifdef USE_ICONV
+	if (ip->bw_iconv_fd != (iconv_t)-1)
+	{
+	    const char	*from;
+	    size_t	fromlen;
+	    char	*to;
+	    size_t	tolen;
+
+	    // Convert with iconv().
+	    if (ip->bw_restlen > 0)
+	    {
+		char *fp;
+
+		// Need to concatenate the remainder of the previous call and
+		// the bytes of the current call.  Use the end of the
+		// conversion buffer for this.
+		fromlen = len + ip->bw_restlen;
+		fp = (char *)ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
+		mch_memmove(fp, ip->bw_rest, (size_t)ip->bw_restlen);
+		mch_memmove(fp + ip->bw_restlen, buf, (size_t)len);
+		from = fp;
+		tolen = ip->bw_conv_buflen - fromlen;
+	    }
+	    else
+	    {
+		from = (const char *)buf;
+		fromlen = len;
+		tolen = ip->bw_conv_buflen;
+	    }
+	    to = (char *)ip->bw_conv_buf;
+
+	    if (ip->bw_first)
+	    {
+		size_t	save_len = tolen;
+
+		// output the initial shift state sequence
+		(void)iconv(ip->bw_iconv_fd, NULL, NULL, &to, &tolen);
+
+		// There is a bug in iconv() on Linux (which appears to be
+		// wide-spread) which sets "to" to NULL and messes up "tolen".
+		if (to == NULL)
+		{
+		    to = (char *)ip->bw_conv_buf;
+		    tolen = save_len;
+		}
+		ip->bw_first = FALSE;
+	    }
+
+	    // If iconv() has an error or there is not enough room, fail.
+	    if ((iconv(ip->bw_iconv_fd, (void *)&from, &fromlen, &to, &tolen)
+			== (size_t)-1 && ICONV_ERRNO != ICONV_EINVAL)
+						    || fromlen > CONV_RESTLEN)
+	    {
+		ip->bw_conv_error = TRUE;
+		return FAIL;
+	    }
+
+	    // copy remainder to ip->bw_rest[] to be used for the next call.
+	    if (fromlen > 0)
+		mch_memmove(ip->bw_rest, (void *)from, fromlen);
+	    ip->bw_restlen = (int)fromlen;
+
+	    buf = ip->bw_conv_buf;
+	    len = (int)((char_u *)to - ip->bw_conv_buf);
+	}
+#endif
+    }
+
+    if (ip->bw_fd < 0)
+	// Only checking conversion, which is OK if we get here.
+	return OK;
+
+#ifdef FEAT_CRYPT
+    if (flags & FIO_ENCRYPTED)
+    {
+	// Encrypt the data. Do it in-place if possible, otherwise use an
+	// allocated buffer.
+# ifdef CRYPT_NOT_INPLACE
+	if (crypt_works_inplace(ip->bw_buffer->b_cryptstate))
+	{
+# endif
+	    crypt_encode_inplace(ip->bw_buffer->b_cryptstate, buf, len);
+# ifdef CRYPT_NOT_INPLACE
+	}
+	else
+	{
+	    char_u *outbuf;
+
+	    len = crypt_encode_alloc(curbuf->b_cryptstate, buf, len, &outbuf);
+	    if (len == 0)
+		return OK;  // Crypt layer is buffering, will flush later.
+	    wlen = write_eintr(ip->bw_fd, outbuf, len);
+	    vim_free(outbuf);
+	    return (wlen < len) ? FAIL : OK;
+	}
+# endif
+    }
+#endif
+
+    wlen = write_eintr(ip->bw_fd, buf, len);
+    return (wlen < len) ? FAIL : OK;
+}
+
+/*
+ * Check modification time of file, before writing to it.
+ * The size isn't checked, because using a tool like "gzip" takes care of
+ * using the same timestamp but can't set the size.
+ */
+    static int
+check_mtime(buf_T *buf, stat_T *st)
+{
+    if (buf->b_mtime_read != 0
+	    && time_differs((long)st->st_mtime, buf->b_mtime_read))
+    {
+	msg_scroll = TRUE;	    // don't overwrite messages here
+	msg_silent = 0;		    // must give this prompt
+	// don't use emsg() here, don't want to flush the buffers
+	msg_attr(_("WARNING: The file has been changed since reading it!!!"),
+						       HL_ATTR(HLF_E));
+	if (ask_yesno((char_u *)_("Do you really want to write to it"),
+								 TRUE) == 'n')
+	    return FAIL;
+	msg_scroll = FALSE;	    // always overwrite the file message now
+    }
+    return OK;
+}
+
+/*
+ * Generate a BOM in "buf[4]" for encoding "name".
+ * Return the length of the BOM (zero when no BOM).
+ */
+    static int
+make_bom(char_u *buf, char_u *name)
+{
+    int		flags;
+    char_u	*p;
+
+    flags = get_fio_flags(name);
+
+    // Can't put a BOM in a non-Unicode file.
+    if (flags == FIO_LATIN1 || flags == 0)
+	return 0;
+
+    if (flags == FIO_UTF8)	// UTF-8
+    {
+	buf[0] = 0xef;
+	buf[1] = 0xbb;
+	buf[2] = 0xbf;
+	return 3;
+    }
+    p = buf;
+    (void)ucs2bytes(0xfeff, &p, flags);
+    return (int)(p - buf);
+}
+
+#ifdef UNIX
+    static void
+set_file_time(
+    char_u  *fname,
+    time_t  atime,	    // access time
+    time_t  mtime)	    // modification time
+{
+# if defined(HAVE_UTIME) && defined(HAVE_UTIME_H)
+    struct utimbuf  buf;
+
+    buf.actime	= atime;
+    buf.modtime	= mtime;
+    (void)utime((char *)fname, &buf);
+# else
+#  if defined(HAVE_UTIMES)
+    struct timeval  tvp[2];
+
+    tvp[0].tv_sec   = atime;
+    tvp[0].tv_usec  = 0;
+    tvp[1].tv_sec   = mtime;
+    tvp[1].tv_usec  = 0;
+#   ifdef NeXT
+    (void)utimes((char *)fname, tvp);
+#   else
+    (void)utimes((char *)fname, (const struct timeval *)&tvp);
+#   endif
+#  endif
+# endif
+}
+#endif // UNIX
+
+/*
+ * buf_write() - write to file "fname" lines "start" through "end"
+ *
+ * We do our own buffering here because fwrite() is so slow.
+ *
+ * If "forceit" is true, we don't care for errors when attempting backups.
+ * In case of an error everything possible is done to restore the original
+ * file.  But when "forceit" is TRUE, we risk losing it.
+ *
+ * When "reset_changed" is TRUE and "append" == FALSE and "start" == 1 and
+ * "end" == curbuf->b_ml.ml_line_count, reset curbuf->b_changed.
+ *
+ * This function must NOT use NameBuff (because it's called by autowrite()).
+ *
+ * return FAIL for failure, OK otherwise
+ */
+    int
+buf_write(
+    buf_T	    *buf,
+    char_u	    *fname,
+    char_u	    *sfname,
+    linenr_T	    start,
+    linenr_T	    end,
+    exarg_T	    *eap,		// for forced 'ff' and 'fenc', can be
+					// NULL!
+    int		    append,		// append to the file
+    int		    forceit,
+    int		    reset_changed,
+    int		    filtering)
+{
+    int		    fd;
+    char_u	    *backup = NULL;
+    int		    backup_copy = FALSE; // copy the original file?
+    int		    dobackup;
+    char_u	    *ffname;
+    char_u	    *wfname = NULL;	// name of file to write to
+    char_u	    *s;
+    char_u	    *ptr;
+    char_u	    c;
+    int		    len;
+    linenr_T	    lnum;
+    long	    nchars;
+    char_u	    *errmsg = NULL;
+    int		    errmsg_allocated = FALSE;
+    char_u	    *errnum = NULL;
+    char_u	    *buffer;
+    char_u	    smallbuf[SMALLBUFSIZE];
+    char_u	    *backup_ext;
+    int		    bufsize;
+    long	    perm;		    // file permissions
+    int		    retval = OK;
+    int		    newfile = FALSE;	    // TRUE if file doesn't exist yet
+    int		    msg_save = msg_scroll;
+    int		    overwriting;	    // TRUE if writing over original
+    int		    no_eol = FALSE;	    // no end-of-line written
+    int		    device = FALSE;	    // writing to a device
+    stat_T	    st_old;
+    int		    prev_got_int = got_int;
+    int		    checking_conversion;
+    int		    file_readonly = FALSE;  // overwritten file is read-only
+    static char	    *err_readonly = "is read-only (cannot override: \"W\" in 'cpoptions')";
+#if defined(UNIX)			    // XXX fix me sometime?
+    int		    made_writable = FALSE;  // 'w' bit has been set
+#endif
+					// writing everything
+    int		    whole = (start == 1 && end == buf->b_ml.ml_line_count);
+    linenr_T	    old_line_count = buf->b_ml.ml_line_count;
+    int		    attr;
+    int		    fileformat;
+    int		    write_bin;
+    struct bw_info  write_info;		// info for buf_write_bytes()
+    int		    converted = FALSE;
+    int		    notconverted = FALSE;
+    char_u	    *fenc;		// effective 'fileencoding'
+    char_u	    *fenc_tofree = NULL; // allocated "fenc"
+    int		    wb_flags = 0;
+#ifdef HAVE_ACL
+    vim_acl_T	    acl = NULL;		// ACL copied from original file to
+					// backup or new file
+#endif
+#ifdef FEAT_PERSISTENT_UNDO
+    int		    write_undo_file = FALSE;
+    context_sha256_T sha_ctx;
+#endif
+    unsigned int    bkc = get_bkc_value(buf);
+
+    if (fname == NULL || *fname == NUL)	// safety check
+	return FAIL;
+    if (buf->b_ml.ml_mfp == NULL)
+    {
+	// This can happen during startup when there is a stray "w" in the
+	// vimrc file.
+	emsg(_(e_emptybuf));
+	return FAIL;
+    }
+
+    // Disallow writing from .exrc and .vimrc in current directory for
+    // security reasons.
+    if (check_secure())
+	return FAIL;
+
+    // Avoid a crash for a long name.
+    if (STRLEN(fname) >= MAXPATHL)
+    {
+	emsg(_(e_longname));
+	return FAIL;
+    }
+
+    // must init bw_conv_buf and bw_iconv_fd before jumping to "fail"
+    write_info.bw_conv_buf = NULL;
+    write_info.bw_conv_error = FALSE;
+    write_info.bw_conv_error_lnum = 0;
+    write_info.bw_restlen = 0;
+#ifdef USE_ICONV
+    write_info.bw_iconv_fd = (iconv_t)-1;
+#endif
+#ifdef FEAT_CRYPT
+    write_info.bw_buffer = buf;
+#endif
+
+    // After writing a file changedtick changes but we don't want to display
+    // the line.
+    ex_no_reprint = TRUE;
+
+    // If there is no file name yet, use the one for the written file.
+    // BF_NOTEDITED is set to reflect this (in case the write fails).
+    // Don't do this when the write is for a filter command.
+    // Don't do this when appending.
+    // Only do this when 'cpoptions' contains the 'F' flag.
+    if (buf->b_ffname == NULL
+	    && reset_changed
+	    && whole
+	    && buf == curbuf
+#ifdef FEAT_QUICKFIX
+	    && !bt_nofilename(buf)
+#endif
+	    && !filtering
+	    && (!append || vim_strchr(p_cpo, CPO_FNAMEAPP) != NULL)
+	    && vim_strchr(p_cpo, CPO_FNAMEW) != NULL)
+    {
+	if (set_rw_fname(fname, sfname) == FAIL)
+	    return FAIL;
+	buf = curbuf;	    // just in case autocmds made "buf" invalid
+    }
+
+    if (sfname == NULL)
+	sfname = fname;
+    // For Unix: Use the short file name whenever possible.
+    // Avoids problems with networks and when directory names are changed.
+    // Don't do this for MS-DOS, a "cd" in a sub-shell may have moved us to
+    // another directory, which we don't detect
+    ffname = fname;			    // remember full fname
+#ifdef UNIX
+    fname = sfname;
+#endif
+
+    if (buf->b_ffname != NULL && fnamecmp(ffname, buf->b_ffname) == 0)
+	overwriting = TRUE;
+    else
+	overwriting = FALSE;
+
+    if (exiting)
+	settmode(TMODE_COOK);	    // when exiting allow typeahead now
+
+    ++no_wait_return;		    // don't wait for return yet
+
+    // Set '[ and '] marks to the lines to be written.
+    buf->b_op_start.lnum = start;
+    buf->b_op_start.col = 0;
+    buf->b_op_end.lnum = end;
+    buf->b_op_end.col = 0;
+
+    {
+	aco_save_T	aco;
+	int		buf_ffname = FALSE;
+	int		buf_sfname = FALSE;
+	int		buf_fname_f = FALSE;
+	int		buf_fname_s = FALSE;
+	int		did_cmd = FALSE;
+	int		nofile_err = FALSE;
+	int		empty_memline = (buf->b_ml.ml_mfp == NULL);
+	bufref_T	bufref;
+
+	// Apply PRE autocommands.
+	// Set curbuf to the buffer to be written.
+	// Careful: The autocommands may call buf_write() recursively!
+	if (ffname == buf->b_ffname)
+	    buf_ffname = TRUE;
+	if (sfname == buf->b_sfname)
+	    buf_sfname = TRUE;
+	if (fname == buf->b_ffname)
+	    buf_fname_f = TRUE;
+	if (fname == buf->b_sfname)
+	    buf_fname_s = TRUE;
+
+	// set curwin/curbuf to buf and save a few things
+	aucmd_prepbuf(&aco, buf);
+	set_bufref(&bufref, buf);
+
+	if (append)
+	{
+	    if (!(did_cmd = apply_autocmds_exarg(EVENT_FILEAPPENDCMD,
+					 sfname, sfname, FALSE, curbuf, eap)))
+	    {
+#ifdef FEAT_QUICKFIX
+		if (overwriting && bt_nofilename(curbuf))
+		    nofile_err = TRUE;
+		else
+#endif
+		    apply_autocmds_exarg(EVENT_FILEAPPENDPRE,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    }
+	}
+	else if (filtering)
+	{
+	    apply_autocmds_exarg(EVENT_FILTERWRITEPRE,
+					    NULL, sfname, FALSE, curbuf, eap);
+	}
+	else if (reset_changed && whole)
+	{
+	    int was_changed = curbufIsChanged();
+
+	    did_cmd = apply_autocmds_exarg(EVENT_BUFWRITECMD,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    if (did_cmd)
+	    {
+		if (was_changed && !curbufIsChanged())
+		{
+		    // Written everything correctly and BufWriteCmd has reset
+		    // 'modified': Correct the undo information so that an
+		    // undo now sets 'modified'.
+		    u_unchanged(curbuf);
+		    u_update_save_nr(curbuf);
+		}
+	    }
+	    else
+	    {
+#ifdef FEAT_QUICKFIX
+		if (overwriting && bt_nofilename(curbuf))
+		    nofile_err = TRUE;
+		else
+#endif
+		    apply_autocmds_exarg(EVENT_BUFWRITEPRE,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    }
+	}
+	else
+	{
+	    if (!(did_cmd = apply_autocmds_exarg(EVENT_FILEWRITECMD,
+					 sfname, sfname, FALSE, curbuf, eap)))
+	    {
+#ifdef FEAT_QUICKFIX
+		if (overwriting && bt_nofilename(curbuf))
+		    nofile_err = TRUE;
+		else
+#endif
+		    apply_autocmds_exarg(EVENT_FILEWRITEPRE,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    }
+	}
+
+	// restore curwin/curbuf and a few other things
+	aucmd_restbuf(&aco);
+
+	// In three situations we return here and don't write the file:
+	// 1. the autocommands deleted or unloaded the buffer.
+	// 2. The autocommands abort script processing.
+	// 3. If one of the "Cmd" autocommands was executed.
+	if (!bufref_valid(&bufref))
+	    buf = NULL;
+	if (buf == NULL || (buf->b_ml.ml_mfp == NULL && !empty_memline)
+				       || did_cmd || nofile_err
+#ifdef FEAT_EVAL
+				       || aborting()
+#endif
+				       )
+	{
+	    --no_wait_return;
+	    msg_scroll = msg_save;
+	    if (nofile_err)
+		emsg(_("E676: No matching autocommands for acwrite buffer"));
+
+	    if (nofile_err
+#ifdef FEAT_EVAL
+		    || aborting()
+#endif
+		    )
+		// An aborting error, interrupt or exception in the
+		// autocommands.
+		return FAIL;
+	    if (did_cmd)
+	    {
+		if (buf == NULL)
+		    // The buffer was deleted.  We assume it was written
+		    // (can't retry anyway).
+		    return OK;
+		if (overwriting)
+		{
+		    // Assume the buffer was written, update the timestamp.
+		    ml_timestamp(buf);
+		    if (append)
+			buf->b_flags &= ~BF_NEW;
+		    else
+			buf->b_flags &= ~BF_WRITE_MASK;
+		}
+		if (reset_changed && buf->b_changed && !append
+			&& (overwriting || vim_strchr(p_cpo, CPO_PLUS) != NULL))
+		    // Buffer still changed, the autocommands didn't work
+		    // properly.
+		    return FAIL;
+		return OK;
+	    }
+#ifdef FEAT_EVAL
+	    if (!aborting())
+#endif
+		emsg(_("E203: Autocommands deleted or unloaded buffer to be written"));
+	    return FAIL;
+	}
+
+	// The autocommands may have changed the number of lines in the file.
+	// When writing the whole file, adjust the end.
+	// When writing part of the file, assume that the autocommands only
+	// changed the number of lines that are to be written (tricky!).
+	if (buf->b_ml.ml_line_count != old_line_count)
+	{
+	    if (whole)						// write all
+		end = buf->b_ml.ml_line_count;
+	    else if (buf->b_ml.ml_line_count > old_line_count)	// more lines
+		end += buf->b_ml.ml_line_count - old_line_count;
+	    else						// less lines
+	    {
+		end -= old_line_count - buf->b_ml.ml_line_count;
+		if (end < start)
+		{
+		    --no_wait_return;
+		    msg_scroll = msg_save;
+		    emsg(_("E204: Autocommand changed number of lines in unexpected way"));
+		    return FAIL;
+		}
+	    }
+	}
+
+	// The autocommands may have changed the name of the buffer, which may
+	// be kept in fname, ffname and sfname.
+	if (buf_ffname)
+	    ffname = buf->b_ffname;
+	if (buf_sfname)
+	    sfname = buf->b_sfname;
+	if (buf_fname_f)
+	    fname = buf->b_ffname;
+	if (buf_fname_s)
+	    fname = buf->b_sfname;
+    }
+
+#ifdef FEAT_NETBEANS_INTG
+    if (netbeans_active() && isNetbeansBuffer(buf))
+    {
+	if (whole)
+	{
+	    // b_changed can be 0 after an undo, but we still need to write
+	    // the buffer to NetBeans.
+	    if (buf->b_changed || isNetbeansModified(buf))
+	    {
+		--no_wait_return;		// may wait for return now
+		msg_scroll = msg_save;
+		netbeans_save_buffer(buf);	// no error checking...
+		return retval;
+	    }
+	    else
+	    {
+		errnum = (char_u *)"E656: ";
+		errmsg = (char_u *)_("NetBeans disallows writes of unmodified buffers");
+		buffer = NULL;
+		goto fail;
+	    }
+	}
+	else
+	{
+	    errnum = (char_u *)"E657: ";
+	    errmsg = (char_u *)_("Partial writes disallowed for NetBeans buffers");
+	    buffer = NULL;
+	    goto fail;
+	}
+    }
+#endif
+
+    if (shortmess(SHM_OVER) && !exiting)
+	msg_scroll = FALSE;	    // overwrite previous file message
+    else
+	msg_scroll = TRUE;	    // don't overwrite previous file message
+    if (!filtering)
+	filemess(buf,
+#ifndef UNIX
+		sfname,
+#else
+		fname,
+#endif
+		    (char_u *)"", 0);	// show that we are busy
+    msg_scroll = FALSE;		    // always overwrite the file message now
+
+    buffer = alloc(WRITEBUFSIZE);
+    if (buffer == NULL)		    // can't allocate big buffer, use small
+				    // one (to be able to write when out of
+				    // memory)
+    {
+	buffer = smallbuf;
+	bufsize = SMALLBUFSIZE;
+    }
+    else
+	bufsize = WRITEBUFSIZE;
+
+    // Get information about original file (if there is one).
+#if defined(UNIX)
+    st_old.st_dev = 0;
+    st_old.st_ino = 0;
+    perm = -1;
+    if (mch_stat((char *)fname, &st_old) < 0)
+	newfile = TRUE;
+    else
+    {
+	perm = st_old.st_mode;
+	if (!S_ISREG(st_old.st_mode))		// not a file
+	{
+	    if (S_ISDIR(st_old.st_mode))
+	    {
+		errnum = (char_u *)"E502: ";
+		errmsg = (char_u *)_("is a directory");
+		goto fail;
+	    }
+	    if (mch_nodetype(fname) != NODE_WRITABLE)
+	    {
+		errnum = (char_u *)"E503: ";
+		errmsg = (char_u *)_("is not a file or writable device");
+		goto fail;
+	    }
+	    // It's a device of some kind (or a fifo) which we can write to
+	    // but for which we can't make a backup.
+	    device = TRUE;
+	    newfile = TRUE;
+	    perm = -1;
+	}
+    }
+#else // !UNIX
+    // Check for a writable device name.
+    c = mch_nodetype(fname);
+    if (c == NODE_OTHER)
+    {
+	errnum = (char_u *)"E503: ";
+	errmsg = (char_u *)_("is not a file or writable device");
+	goto fail;
+    }
+    if (c == NODE_WRITABLE)
+    {
+# if defined(MSWIN)
+	// MS-Windows allows opening a device, but we will probably get stuck
+	// trying to write to it.
+	if (!p_odev)
+	{
+	    errnum = (char_u *)"E796: ";
+	    errmsg = (char_u *)_("writing to device disabled with 'opendevice' option");
+	    goto fail;
+	}
+# endif
+	device = TRUE;
+	newfile = TRUE;
+	perm = -1;
+    }
+    else
+    {
+	perm = mch_getperm(fname);
+	if (perm < 0)
+	    newfile = TRUE;
+	else if (mch_isdir(fname))
+	{
+	    errnum = (char_u *)"E502: ";
+	    errmsg = (char_u *)_("is a directory");
+	    goto fail;
+	}
+	if (overwriting)
+	    (void)mch_stat((char *)fname, &st_old);
+    }
+#endif // !UNIX
+
+    if (!device && !newfile)
+    {
+	// Check if the file is really writable (when renaming the file to
+	// make a backup we won't discover it later).
+	file_readonly = check_file_readonly(fname, (int)perm);
+
+	if (!forceit && file_readonly)
+	{
+	    if (vim_strchr(p_cpo, CPO_FWRITE) != NULL)
+	    {
+		errnum = (char_u *)"E504: ";
+		errmsg = (char_u *)_(err_readonly);
+	    }
+	    else
+	    {
+		errnum = (char_u *)"E505: ";
+		errmsg = (char_u *)_("is read-only (add ! to override)");
+	    }
+	    goto fail;
+	}
+
+	// Check if the timestamp hasn't changed since reading the file.
+	if (overwriting)
+	{
+	    retval = check_mtime(buf, &st_old);
+	    if (retval == FAIL)
+		goto fail;
+	}
+    }
+
+#ifdef HAVE_ACL
+    // For systems that support ACL: get the ACL from the original file.
+    if (!newfile)
+	acl = mch_get_acl(fname);
+#endif
+
+    // If 'backupskip' is not empty, don't make a backup for some files.
+    dobackup = (p_wb || p_bk || *p_pm != NUL);
+#ifdef FEAT_WILDIGN
+    if (dobackup && *p_bsk != NUL && match_file_list(p_bsk, sfname, ffname))
+	dobackup = FALSE;
+#endif
+
+    // Save the value of got_int and reset it.  We don't want a previous
+    // interruption cancel writing, only hitting CTRL-C while writing should
+    // abort it.
+    prev_got_int = got_int;
+    got_int = FALSE;
+
+    // Mark the buffer as 'being saved' to prevent changed buffer warnings
+    buf->b_saving = TRUE;
+
+    // If we are not appending or filtering, the file exists, and the
+    // 'writebackup', 'backup' or 'patchmode' option is set, need a backup.
+    // When 'patchmode' is set also make a backup when appending.
+    //
+    // Do not make any backup, if 'writebackup' and 'backup' are both switched
+    // off.  This helps when editing large files on almost-full disks.
+    if (!(append && *p_pm == NUL) && !filtering && perm >= 0 && dobackup)
+    {
+#if defined(UNIX) || defined(MSWIN)
+	stat_T	    st;
+#endif
+
+	if ((bkc & BKC_YES) || append)	// "yes"
+	    backup_copy = TRUE;
+#if defined(UNIX) || defined(MSWIN)
+	else if ((bkc & BKC_AUTO))	// "auto"
+	{
+	    int		i;
+
+# ifdef UNIX
+	    // Don't rename the file when:
+	    // - it's a hard link
+	    // - it's a symbolic link
+	    // - we don't have write permission in the directory
+	    // - we can't set the owner/group of the new file
+	    if (st_old.st_nlink > 1
+		    || mch_lstat((char *)fname, &st) < 0
+		    || st.st_dev != st_old.st_dev
+		    || st.st_ino != st_old.st_ino
+#  ifndef HAVE_FCHOWN
+		    || st.st_uid != st_old.st_uid
+		    || st.st_gid != st_old.st_gid
+#  endif
+		    )
+		backup_copy = TRUE;
+