Tcl Source Code

 * are for internal use only.  Make sure they do not overlap with the public
 * values above.
 *
 * The Tcl*Scan*Element() routines make a determination which of 4 modes of
 * conversion is most appropriate for Tcl*Convert*Element() to perform, and
 * sets two bits of the flags value to indicate the mode selected.
 *



























 * For more details, see the comments on the Tcl*Scan*Element and
 * Tcl*Convert*Element routines.
 */

enum ConvertFlags {
    CONVERT_NONE = 0,		/* The element needs no quoting. Its literal
				 * string is suitable as is. */
    DONT_USE_BRACES = TCL_DONT_USE_BRACES,
				/* The caller is insisting that brace quoting
				 * not be used when converting the list
				 * element. */
    CONVERT_BRACE = 2,		/* The conversion should be enclosing the
				 * literal string in braces. */
    CONVERT_ESCAPE = 4,		/* The conversion should be using backslashes
				 * to escape any characters in the string that
				 * require it. */
    DONT_QUOTE_HASH = TCL_DONT_QUOTE_HASH,
				/* The caller insists that a leading hash
				 * character ('#') should *not* be quoted. This
				 * is appropriate when the caller can guarantee
				 * the element is not the first element of a
				 * list, so [eval] cannot mis-parse the element
				 * as a comment.*/
    CONVERT_MASK = CONVERT_BRACE | CONVERT_ESCAPE,
				/* A mask value used to extract the conversion
				 * mode from the flags argument.
				 *
				 * Also indicates a strange conversion mode
				 * where all special characters are escaped
				 * with backslashes *except for braces*. This
				 * is a strange and unnecessary case, but it's
				 * part of the historical way in which lists
				 * have been formatted in Tcl. To experiment
				 * with removing this case, define the value of
				 * COMPAT to be 0. */
    CONVERT_ANY = 16		/* The caller of TclScanElement() declares it
				 * can make no promise about what public flags
				 * will be passed to the matching call of
				 * TclConvertElement(). As such,
				 * TclScanElement() has to determine the worst
				 * case destination buffer length over all
				 * possibilities, and in other cases this means
				 * an overestimate of the required size.
				 *
				 * Used only by callers of TclScanElement().
				 * The flag value produced by a call to
				 * Tcl*Scan*Element() will never leave this
				 * bit set. */
};
#ifndef COMPAT
#define COMPAT 1
#endif

/*
 * Prototypes for functions defined later in this file.
 */

static void		ClearHash(Tcl_HashTable *tablePtr);
static void		FreeProcessGlobalValue(void *clientData);

     * the element #{a"b} like this:
     *			{#{a"b}}
     * and not like this:
     *			\#{a\"b}
     * This is inconsistent with [list x{a"b}], but we will not change that now.
     * Set that preference here so that we compute a tight size requirement.
     */
    if ((*src == '#') && !(*flagPtr & DONT_QUOTE_HASH)) {
	preferBrace = 1;
    }
#endif

    if ((*p == '{') || (*p == '"')) {
	/*
	 * Must escape or protect so leading character of value is not

	bytesNeeded += extra;

	/*
	 * Make room to escape leading #, if needed.
	 */

	if ((*src == '#') && !(*flagPtr & DONT_QUOTE_HASH)) {
	    bytesNeeded++;
	}
	*flagPtr = CONVERT_ESCAPE;
	return bytesNeeded;
    }
    if (*flagPtr & CONVERT_ANY) {
	/*
	 * The caller has not let us know what flags it will pass to
	 * TclConvertElement() so compute the max size we might need for any
	 * possible choice.  Normally the formatting using escape sequences is
	 * the longer one, and a minimum "extra" value of 2 makes sure we
	 * don't request too small a buffer in those edge cases where that's
	 * not true.
	 */

	if (extra < 2) {
	    extra = 2;
	}
	*flagPtr &= ~CONVERT_ANY;
	*flagPtr |= DONT_USE_BRACES;
    }
    if (forbidNone) {
	/*
	 * We must request some form of quoting of escaping...
	 */

#if COMPAT
	if (preferEscape && !preferBrace) {
	    /*
	     * If we are quoting solely due to ] or internal " characters use
	     * the CONVERT_MASK mode where we escape all special characters
	     * except for braces. "extra" counted space needed to escape
	     * braces too, so subtract "braceCount" to get our actual needs.
	     */

	    bytesNeeded += (extra - braceCount);
	    /* Make room to escape leading #, if needed. */
	    if ((*src == '#') && !(*flagPtr & DONT_QUOTE_HASH)) {
		bytesNeeded++;
	    }

	    /*
	     * If the caller reports it will direct TclConvertElement() to
	     * use full escapes on the element, add back the bytes needed to
	     * escape the braces.
	     */

	    if (*flagPtr & DONT_USE_BRACES) {
		bytesNeeded += braceCount;
	    }
	    *flagPtr = CONVERT_MASK;
	    return bytesNeeded;
	}
#endif /* COMPAT */
	if (*flagPtr & DONT_USE_BRACES) {
	    /*
	     * If the caller reports it will direct TclConvertElement() to
	     * use escapes, add the extra bytes needed to have room for them.
	     */

	    bytesNeeded += extra;

	    /*
	     * Make room to escape leading #, if needed.
	     */

	    if ((*src == '#') && !(*flagPtr & DONT_QUOTE_HASH)) {
		bytesNeeded++;
	    }
	} else {
	    /*
	     * Add 2 bytes for room for the enclosing braces.
	     */

	    bytesNeeded += 2;
	}
	*flagPtr = CONVERT_BRACE;
	return bytesNeeded;
    }

    /*
     * So far, no need to quote or escape anything.
     */

    if ((*src == '#') && !(*flagPtr & DONT_QUOTE_HASH)) {
	/*
	 * If we need to quote a leading #, make room to enclose in braces.
	 */

	bytesNeeded += 2;
    }
    *flagPtr = CONVERT_NONE;

    int conversion = flags & CONVERT_MASK;
    char *p = dst;

    /*
     * Let the caller demand we use escape sequences rather than braces.
     */

    if ((flags & DONT_USE_BRACES) && (conversion & CONVERT_BRACE)) {
	conversion = CONVERT_ESCAPE;
    }

    /*
     * No matter what the caller demands, empty string must be braced!
     */

    if ((src == NULL) || (length == 0) || (*src == '\0' && length == TCL_INDEX_NONE)) {
	p[0] = '{';
	p[1] = '}';
	return 2;
    }

    /*
     * Escape leading hash as needed and requested.
     */

    if ((*src == '#') && !(flags & DONT_QUOTE_HASH)) {
	if (conversion == CONVERT_ESCAPE) {
	    p[0] = '\\';
	    p[1] = '#';
	    p += 2;
	    src++;
	    length -= (length > 0);
	} else {

    if (argc <= LOCAL_SIZE) {
	flagPtr = localFlags;
    } else {
	flagPtr = (char *)Tcl_Alloc(argc);
    }
    for (i = 0; i < argc; i++) {
	flagPtr[i] = ( i ? DONT_QUOTE_HASH : 0 );
	bytesNeeded += TclScanElement(argv[i], TCL_INDEX_NONE, &flagPtr[i]);
    }
    bytesNeeded += argc;

    /*
     * Pass two: copy into the result area.
     */

    result = (char *)Tcl_Alloc(bytesNeeded);
    dst = result;
    for (i = 0; i < argc; i++) {
	flagPtr[i] |= ( i ? DONT_QUOTE_HASH : 0 );
	dst += TclConvertElement(argv[i], TCL_INDEX_NONE, dst, flagPtr[i]);
	*dst = ' ';
	dst++;
    }
    dst[-1] = 0;

    if (flagPtr != localFlags) {

	while ((--dst >= dsPtr->string) && TclIsSpaceProcM(*dst)) {
	}

	/* Call again without whitespace to confound things. */
	quoteHash = !TclNeedSpace(dsPtr->string, dst+1);
    }
    if (!quoteHash) {
	flags |= DONT_QUOTE_HASH;
    }
    newSize = dsPtr->length + needSpace + TclScanElement(element, TCL_INDEX_NONE, &flags);
    if (!quoteHash) {
	flags |= DONT_QUOTE_HASH;
    }

    /*
     * Allocate a larger buffer for the string if the current one isn't large
     * enough. Allocate extra space in the new buffer so that there will be
     * room to grow before we have to allocate again. SPECIAL NOTE: must use
     * memcpy, not strcpy, to copy the string to a larger buffer, since there