How can I find unused functions in a PHP project

How can I find unused functions in a PHP project?
Are there features or API's built into PHP that will allow me to analyse my codebase - for example Reflectiontoken_get_all()?
Are these API's feature rich enough for me not to have to rely on a third party tool to perform this type of analysis?

Answer :


Thanks Greg and Dave for the feedback. Wasn't quite what I was looking for, but I decided to put a bit of time into researching it and came up with this quick and dirty solution:
<?php
    $functions = array();
    $path = "/path/to/my/php/project";
    define_dir($path, $functions);
    reference_dir($path, $functions);
    echo
        "<table>" .
            "<tr>" .
                "<th>Name</th>" .
                "<th>Defined</th>" .
                "<th>Referenced</th>" .
            "</tr>";
    foreach ($functions as $name => $value) {
        echo
            "<tr>" . 
                "<td>" . htmlentities($name) . "</td>" .
                "<td>" . (isset($value[0]) ? count($value[0]) : "-") . "</td>" .
                "<td>" . (isset($value[1]) ? count($value[1]) : "-") . "</td>" .
            "</tr>";
    }
    echo "</table>";
    function define_dir($path, &$functions) {
        if ($dir = opendir($path)) {
            while (($file = readdir($dir)) !== false) {
                if (substr($file, 0, 1) == ".") continue;
                if (is_dir($path . "/" . $file)) {
                    define_dir($path . "/" . $file, $functions);
                } else {
                    if (substr($file, - 4, 4) != ".php") continue;
                    define_file($path . "/" . $file, $functions);
                }
            }
        }       
    }
    function define_file($path, &$functions) {
        $tokens = token_get_all(file_get_contents($path));
        for ($i = 0; $i < count($tokens); $i++) {
            $token = $tokens[$i];
            if (is_array($token)) {
                if ($token[0] != T_FUNCTION) continue;
                $i++;
                $token = $tokens[$i];
                if ($token[0] != T_WHITESPACE) die("T_WHITESPACE");
                $i++;
                $token = $tokens[$i];
                if ($token[0] != T_STRING) die("T_STRING");
                $functions[$token[1]][0][] = array($path, $token[2]);
            }
        }
    }
    function reference_dir($path, &$functions) {
        if ($dir = opendir($path)) {
            while (($file = readdir($dir)) !== false) {
                if (substr($file, 0, 1) == ".") continue;
                if (is_dir($path . "/" . $file)) {
                    reference_dir($path . "/" . $file, $functions);
                } else {
                    if (substr($file, - 4, 4) != ".php") continue;
                    reference_file($path . "/" . $file, $functions);
                }
            }
        }       
    }
    function reference_file($path, &$functions) {
        $tokens = token_get_all(file_get_contents($path));
        for ($i = 0; $i < count($tokens); $i++) {
            $token = $tokens[$i];
            if (is_array($token)) {
                if ($token[0] != T_STRING) continue;
                if ($tokens[$i + 1] != "(") continue;
                $functions[$token[1]][1][] = array($path, $token[2]);
            }
        }
    }
?>
I'll probably spend some more time on it so I can quickly find the files and line numbers of the function definitions and references; this information is being gathered, just not displayed.