ArrayList parseParams()

in src/core/src/main/java/org/apache/jmeter/engine/util/FunctionParser.java [191:253]
60 lines of code
21 McCabe index (conditional complexity)

    ArrayList<CompoundVariable> parseParams(StringReader reader) throws InvalidVariableException {
        ArrayList<CompoundVariable> result = new ArrayList<>();
        StringBuilder buffer = new StringBuilder();
        char[] current = new char[1];
        char previous = ' ';
        int functionRecursion = 0;
        int parenRecursion = 0;
        try {
            while (reader.read(current) == 1) {
                if (current[0] == '\\') { // Process escaped characters
                    buffer.append(current[0]); // Store the \
                    if (reader.read(current) == 0) {
                        break; // end of buffer
                    }
                    previous = ' ';
                    buffer.append(current[0]); // store the following character
                } else if (current[0] == ',' && functionRecursion == 0) {
                    CompoundVariable param = new CompoundVariable();
                    param.setParameters(buffer.toString());
                    buffer.setLength(0);
                    result.add(param);
                } else if (current[0] == ')' && functionRecursion == 0 && parenRecursion == 0) {
                    // Detect functionName() so this does not generate empty string as the parameter
                    if (buffer.length() == 0 && result.isEmpty()){
                        return result;
                    }
                    // Normal exit occurs here
                    CompoundVariable param = new CompoundVariable();
                    param.setParameters(buffer.toString());
                    buffer.setLength(0);
                    result.add(param);
                    return result;
                } else if (current[0] == '{' && previous == '$') {
                    buffer.append(current[0]);
                    previous = current[0];
                    functionRecursion++;
                } else if (current[0] == '}' && functionRecursion > 0) {
                    buffer.append(current[0]);
                    previous = current[0];
                    functionRecursion--;
                } else if (current[0] == ')' && functionRecursion == 0 && parenRecursion > 0) {
                    buffer.append(current[0]);
                    previous = current[0];
                    parenRecursion--;
                } else if (current[0] == '(' && functionRecursion == 0) {
                    buffer.append(current[0]);
                    previous = current[0];
                    parenRecursion++;
                } else {
                    buffer.append(current[0]);
                    previous = current[0];
                }
            }
        } catch (IOException e) {// Should not happen with StringReader
            log.error("Error parsing function: {}", buffer, e);
        }
        // Dropped out, i.e. did not find closing ')'
        log.warn("Probably an invalid function string: {}", buffer);
        CompoundVariable var = new CompoundVariable();
        var.setParameters(buffer.toString());
        result.add(var);
        return result;
    }