<?php
/**
 * Chromium Command Line Switch Parser
 * 
 * This file parses the command lines as they are available in Chromium. The list will
 * automatically be updated every day, and include comments and additional information
 * which is available in Chromium's source-code. Conditions will be converted to readable
 * sentences, the list will be sorted alphabetically and we'll output an JSON file.
 *
 * There's no license on this file. Do with it whatever you want :-)
 *
 * @copyright Copyright (c) 2010 - Peter Beverloo
 * @author Peter Beverloo <peter@lvp-media.com>
 * @package ChromiumTools
 * @version $Id$
 */

if (!isset ($_SERVER ['argc']))
    die ();

$chromeSwitches   = file ('http://src.chromium.org/viewvc/chrome/trunk/src/chrome/common/chrome_switches.cc');
$commentBuffer    = array ();
$currentCondition = '';
$switches     = array ();

function clearifyCondition ($condition)
{
    if (substr ($condition, 0, 7) == 'defined' && strpos ($condition, '||') !== false)
    {
        preg_match_all ('/defined\(([^\)]+)\)/s', $condition, $matches);
        return 'One of these constants must be defined: "' . implode ('", "', $matches [1]) . '".';
    }
    
    if (substr ($condition, 0, 7) == 'defined')
    {
        return 'The constant "' . substr ($condition, 8, -1) . '" must be defined.';
    }
    
    if (substr ($condition, 0, 8) == '!defined')
    {
        return 'The constant "' . substr ($condition, 9, -1) . '" must not be defined.';
    }
    
    return $condition;
}

foreach ($chromeSwitches as $idx => $line)
{
    $line = trim ($line);
    switch (substr ($line, 0, 1))
    {
        case '/': /* comment line */
        {
            $commentBuffer [] = ltrim (substr ($line, 2));
            break;
        }
        
        case 'c': /* const char */
        {
            if (substr ($line, 0, 10) != 'const char')
                continue;
            
            $switchName = substr ($line, strpos ($line, '"') + 1, -2);
            if (substr ($switchName, 0, 5) == 'onst ')
            {
                /* Switch is on the next line, 80-character lines are so.. 1990. This line is over 140 characters in length! */
                $switchName = substr (trim ($chromeSwitches [$idx + 1]), 1, -2);
            }
            
            $switches [$switchName] = array
            (
                'comment'       => implode (' ', $commentBuffer),
                'condition'     => $currentCondition
            );
            
            $commentBuffer = array ();
            break;
        }
        
        case '#': /* condition */
        {
            $directive = substr ($line, 1, strpos ($line, ' ') ?: 8);
            switch (trim ($directive))
            {
                case 'if': /* if-condition */
                {
                    $currentCondition = clearifyCondition (substr ($line, 4));
                    break;
                }
                
                case 'ifndef': /* if not defined */
                {
                    $currentCondition = 'The constant "' . substr ($line, 8) . '" must not be defined.';
                    break;
                }
                
                case 'else': /* reverse the condition */
                {
                    if (strpos ('must not be', $currentCondition) !== false)
                    {
                        $currentCondition = str_replace ('must not be', 'must be', $currentCondition);
                    }
                    else
                    {
                        $currentCondition = str_replace ('must be', 'must not be', $currentCondition);
                    }
                    
                    break;
                }
                
                default: /* reset the condition state */
                {
                    $currentCondition = '';
                }
            }
            
            break;
        }
        
        default: /* reset comment state */
        {
            $commentBuffer = array ();
            break;
        }
    }
}

/**
 * Now sort the switches and generate a list of conditions, so we can refer to
 * them by number instead of having to include the entire condition every time.
 */

$conditionList = array ();
$switchList = array ();

ksort ($switches);
foreach ($switches as $name => $information)
{
    if (strlen ($information ['condition']))
    {
        if (!isset ($conditionList [$information ['condition']]))
        {
            $conditionList [$information ['condition']] = count ($conditionList) + 1;
        }
        
        $information ['condition'] = $conditionList [$information ['condition']];
    }
    
    $switchList [] = array
    (
        'name'      => $name,
        'comment'       => $information ['comment'],
        'condition'     => $information ['condition']
    );
}

/**
 * Done. Now create a JSON file based on the gathered information.
 */

file_put_contents (__DIR__ . '/chromium-command-line-switches.json', json_encode (array
(
    'switches'      => $switchList,
    'conditions'    => array_flip ($conditionList)
)));