Method parseOptions

app/src/main/java/androidx/room/FtsTableInfo.java:128–190

Parses FTS options from the create statement of an FTS table. This method assumes the given create statement is a valid well-formed SQLite statement as defined in the CREATE VIRTUAL TABLE syntax diagram . @param createStatement the "CREATE V

(String createStatement)

     * @return the set of FTS option key and values in the create statement.
     */
    @VisibleForTesting
    @SuppressWarnings("WeakerAccess") /* synthetic access */
    static Set<String> parseOptions(String createStatement) {
        if (createStatement.isEmpty()) {
            return new HashSet<>();
        }

        // Module arguments are within the parenthesis followed by the module name.
        String argsString = createStatement.substring(
                createStatement.indexOf('(') + 1,
                createStatement.lastIndexOf(')'));

        // Split the module argument string by the comma delimiter, keeping track of quotation so
        // so that if the delimiter is found within a string literal we don't substring at the wrong
        // index. SQLite supports four ways of quoting keywords, see:
        // https://www.sqlite.org/lang_keywords.html
        List<String> args = new ArrayList<>();
        ArrayDeque<Character> quoteStack = new ArrayDeque<>();
        int lastDelimiterIndex = -1;
        for (int i = 0; i < argsString.length(); i++) {
            char c = argsString.charAt(i);
            switch (c) {
                case '\'':
                case '"':
                case '`':
                    if (quoteStack.isEmpty()) {
                        quoteStack.push(c);
                    } else if (quoteStack.peek() == c) {
                        quoteStack.pop();
                    }
                    break;
                case '[':
                    if (quoteStack.isEmpty()) {
                        quoteStack.push(c);
                    }
                    break;
                case ']':
                    if (!quoteStack.isEmpty() && quoteStack.peek() == '[') {
                        quoteStack.pop();
                    }
                    break;
                case ',':
                    if (quoteStack.isEmpty()) {
                        args.add(argsString.substring(lastDelimiterIndex + 1, i).trim());
                        lastDelimiterIndex = i;
                    }
                    break;
            }
        }
        args.add(argsString.substring(lastDelimiterIndex + 1).trim()); // Add final argument.

        // Match args against valid options, otherwise they are column definitions.
        HashSet<String> options = new HashSet<>();
        for (String arg : args) {
            for (String validOption : FTS_OPTIONS) {
                if (arg.startsWith(validOption)) {
                    options.add(arg);
                }