install.core.inc

<?php


/**
 * @file
 * API functions for installing Drupal.
 */

/**
 * Do not run the task during the current installation request.
 *
 * This can be used to skip running an installation task when certain
 * conditions are met, even though the task may still show on the list of
 * installation tasks presented to the user. For example, the Drupal installer
 * uses this flag to skip over the database configuration form when valid
 * database connection information is already available from settings.php. It
 * also uses this flag to skip language import tasks when the installation is
 * being performed in English.
 */
define('INSTALL_TASK_SKIP', 1);

/**
 * Run the task on each installation request until the database is set up.
 *
 * This is primarily used by the Drupal installer for bootstrap-related tasks.
 */
define('INSTALL_TASK_RUN_IF_REACHED', 2);

/**
 * Global flag to indicate that a task should be run on each installation
 * request that reaches it, until the database is set up and we are able to
 * record the fact that it already ran.
 *
 * This is the default method for running tasks and should be used for most
 * tasks that occur after the database is set up; these tasks will then run
 * once and be marked complete once they are successfully finished. For
 * example, the Drupal installer uses this flag for the batch installation of
 * modules on the new site, and also for the configuration form that collects
 * basic site information and sets up the site maintenance account.
 */
define('INSTALL_TASK_RUN_IF_NOT_COMPLETED', 3);

/**
 * Installs Drupal either interactively or via an array of passed-in settings.
 *
 * The Drupal installation happens in a series of steps, which may be spread
 * out over multiple page requests. Each request begins by trying to determine
 * the last completed installation step (also known as a "task"), if one is
 * available from a previous request. Control is then passed to the task
 * handler, which processes the remaining tasks that need to be run until (a)
 * an error is thrown, (b) a new page needs to be displayed, or (c) the
 * installation finishes (whichever happens first).
 *
 * @param $settings
 *   An optional array of installation settings. Leave this empty for a normal,
 *   interactive, browser-based installation intended to occur over multiple
 *   page requests. Alternatively, if an array of settings is passed in, the
 *   installer will attempt to use it to perform the installation in a single
 *   page request (optimized for the command line) and not send any output
 *   intended for the web browser. See install_state_defaults() for a list of
 *   elements that are allowed to appear in this array.
 *
 * @see install_state_defaults()
 */
function install_drupal($settings = array()) {
    global $install_state;
    // Initialize the installation state with the settings that were passed in,
    // as well as a boolean indicating whether or not this is an interactive
    // installation.
    $interactive = empty($settings);
    $install_state = $settings + array(
        'interactive' => $interactive,
    ) + install_state_defaults();
    try {
        // Begin the page request. This adds information about the current state of
        // the Drupal installation to the passed-in array.
        install_begin_request($install_state);
        // Based on the installation state, run the remaining tasks for this page
        // request, and collect any output.
        $output = install_run_tasks($install_state);
    } catch (Exception $e) {
        // When an installation error occurs, either send the error to the web
        // browser or pass on the exception so the calling script can use it.
        if ($install_state['interactive']) {
            install_display_output($e->getMessage(), $install_state);
        }
        else {
            throw $e;
        }
    }
    // All available tasks for this page request are now complete. Interactive
    // installations can send output to the browser or redirect the user to the
    // next page.
    if ($install_state['interactive']) {
        if ($install_state['parameters_changed']) {
            // Redirect to the correct page if the URL parameters have changed.
            install_goto(install_redirect_url($install_state));
        }
        elseif (isset($output)) {
            // Display a page only if some output is available. Otherwise it is
            // possible that we are printing a JSON page and theme output should
            // not be shown.
            install_display_output($output, $install_state);
        }
    }
}

/**
 * Returns an array of default settings for the global installation state.
 *
 * The installation state is initialized with these settings at the beginning
 * of each page request. They may evolve during the page request, but they are
 * initialized again once the next request begins.
 *
 * Non-interactive Drupal installations can override some of these default
 * settings by passing in an array to the installation script, most notably
 * 'parameters' (which contains one-time parameters such as 'profile' and
 * 'locale' that are normally passed in via the URL) and 'forms' (which can
 * be used to programmatically submit forms during the installation; the keys
 * of each element indicate the name of the installation task that the form
 * submission is for, and the values are used as the $form_state['values']
 * array that is passed on to the form submission via drupal_form_submit()).
 *
 * @see drupal_form_submit()
 */
function install_state_defaults() {
    $defaults = array(
        // The current task being processed.
'active_task' => NULL,
        // The last task that was completed during the previous installation
        // request.
'completed_task' => NULL,
        // This becomes TRUE only when Drupal's system module is installed.
'database_tables_exist' => FALSE,
        // An array of forms to be programmatically submitted during the
        // installation. The keys of each element indicate the name of the
        // installation task that the form submission is for, and the values are
        // used as the $form_state['values'] array that is passed on to the form
        // submission via drupal_form_submit().
'forms' => array(),
        // This becomes TRUE only at the end of the installation process, after
        // all available tasks have been completed and Drupal is fully installed.
        // It is used by the installer to store correct information in the database
        // about the completed installation, as well as to inform theme functions
        // that all tasks are finished (so that the task list can be displayed
        // correctly).
'installation_finished' => FALSE,
        // Whether or not this installation is interactive. By default this will
        // be set to FALSE if settings are passed in to install_drupal().
'interactive' => TRUE,
        // An array of available languages for the installation.
'locales' => array(),
        // An array of parameters for the installation, pre-populated by the URL
        // or by the settings passed in to install_drupal(). This is primarily
        // used to store 'profile' (the name of the chosen installation profile)
        // and 'locale' (the name of the chosen installation language), since
        // these settings need to persist from page request to page request before
        // the database is available for storage.
'parameters' => array(),
        // Whether or not the parameters have changed during the current page
        // request. For interactive installations, this will trigger a page
        // redirect.
'parameters_changed' => FALSE,
        // An array of information about the chosen installation profile. This will
        // be filled in based on the profile's .info file.
'profile_info' => array(),
        // An array of available installation profiles.
'profiles' => array(),
        // An array of server variables that will be substituted into the global
        // $_SERVER array via drupal_override_server_variables(). Used by
        // non-interactive installations only.
'server' => array(),
        // This becomes TRUE only when a valid database connection can be
        // established.
'settings_verified' => FALSE,
        // Installation tasks can set this to TRUE to force the page request to
        // end (even if there is no themable output), in the case of an interactive
        // installation. This is needed only rarely; for example, it would be used
        // by an installation task that prints JSON output rather than returning a
        // themed page. The most common example of this is during batch processing,
        // but the Drupal installer automatically takes care of setting this
        // parameter properly in that case, so that individual installation tasks
        // which implement the batch API do not need to set it themselves.
'stop_page_request' => FALSE,
        // Installation tasks can set this to TRUE to indicate that the task should
        // be run again, even if it normally wouldn't be. This can be used, for
        // example, if a single task needs to be spread out over multiple page
        // requests, or if it needs to perform some validation before allowing
        // itself to be marked complete. The most common examples of this are batch
        // processing and form submissions, but the Drupal installer automatically
        // takes care of setting this parameter properly in those cases, so that
        // individual installation tasks which implement the batch API or form API
        // do not need to set it themselves.
'task_not_complete' => FALSE,
        // A list of installation tasks which have already been performed during
        // the current page request.
'tasks_performed' => array(),
    );
    return $defaults;
}

/**
 * Begins an installation request, modifying the installation state as needed.
 *
 * This function performs commands that must run at the beginning of every page
 * request. It throws an exception if the installation should not proceed.
 *
 * @param $install_state
 *   An array of information about the current installation state. This is
 *   modified with information gleaned from the beginning of the page request.
 */
function install_begin_request(&$install_state) {
    // Add any installation parameters passed in via the URL.
    $install_state['parameters'] += $_GET;
    // Validate certain core settings that are used throughout the installation.
    if (!empty($install_state['parameters']['profile'])) {
        $install_state['parameters']['profile'] = preg_replace('/[^a-zA-Z_0-9]/', '', $install_state['parameters']['profile']);
    }
    if (!empty($install_state['parameters']['locale'])) {
        $install_state['parameters']['locale'] = preg_replace('/[^a-zA-Z_0-9\\-]/', '', $install_state['parameters']['locale']);
    }
    // Allow command line scripts to override server variables used by Drupal.
    require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
    if (!$install_state['interactive']) {
        drupal_override_server_variables($install_state['server']);
    }
    // The user agent header is used to pass a database prefix in the request when
    // running tests. However, for security reasons, it is imperative that no
    // installation be permitted using such a prefix.
    if (isset($_SERVER['HTTP_USER_AGENT']) && strpos($_SERVER['HTTP_USER_AGENT'], "simpletest") !== FALSE) {
        header($_SERVER['SERVER_PROTOCOL'] . ' 403 Forbidden');
        exit;
    }
    drupal_bootstrap(DRUPAL_BOOTSTRAP_CONFIGURATION);
    // This must go after drupal_bootstrap(), which unsets globals!
    global $conf;
    require_once DRUPAL_ROOT . '/modules/system/system.install';
    require_once DRUPAL_ROOT . '/includes/common.inc';
    require_once DRUPAL_ROOT . '/includes/file.inc';
    require_once DRUPAL_ROOT . '/includes/install.inc';
    require_once DRUPAL_ROOT . '/' . variable_get('path_inc', 'includes/path.inc');
    // Load module basics (needed for hook invokes).
    include_once DRUPAL_ROOT . '/includes/module.inc';
    include_once DRUPAL_ROOT . '/includes/session.inc';
    // Set up $language, so t() caller functions will still work.
    drupal_language_initialize();
    include_once DRUPAL_ROOT . '/includes/entity.inc';
    require_once DRUPAL_ROOT . '/includes/ajax.inc';
    $module_list['system']['filename'] = 'modules/system/system.module';
    $module_list['user']['filename'] = 'modules/user/user.module';
    module_list(TRUE, FALSE, FALSE, $module_list);
    drupal_load('module', 'system');
    drupal_load('module', 'user');
    // Load the cache infrastructure using a "fake" cache implementation that
    // does not attempt to write to the database. We need this during the initial
    // part of the installer because the database is not available yet. We
    // continue to use it even when the database does become available, in order
    // to preserve consistency between interactive and command-line installations
    // (the latter complete in one page request and therefore are forced to
    // continue using the cache implementation they started with) and also
    // because any data put in the cache during the installer is inherently
    // suspect, due to the fact that Drupal is not fully set up yet.
    require_once DRUPAL_ROOT . '/includes/cache.inc';
    require_once DRUPAL_ROOT . '/includes/cache-install.inc';
    $conf['cache_default_class'] = 'DrupalFakeCache';
    // Prepare for themed output. We need to run this at the beginning of the
    // page request to avoid a different theme accidentally getting set. (We also
    // need to run it even in the case of command-line installations, to prevent
    // any code in the installer that happens to initialize the theme system from
    // accessing the database before it is set up yet.)
    drupal_maintenance_theme();
    // Check existing settings.php.
    $install_state['settings_verified'] = install_verify_settings();
    if ($install_state['settings_verified']) {
        // Initialize the database system. Note that the connection
        // won't be initialized until it is actually requested.
        require_once DRUPAL_ROOT . '/includes/database/database.inc';
        // Verify the last completed task in the database, if there is one.
        $task = install_verify_completed_task();
    }
    else {
        $task = NULL;
        // Do not install over a configured settings.php. Check the 'db_url'
        // variable in addition to 'databases', since previous versions of Drupal
        // used that (and we do not want to allow installations on an existing site
        // whose settings file has not yet been updated).
        if (!empty($GLOBALS['databases']) || !empty($GLOBALS['db_url'])) {
            throw new Exception(install_already_done_error());
        }
    }
    // Modify the installation state as appropriate.
    $install_state['completed_task'] = $task;
    $install_state['database_tables_exist'] = !empty($task);
}

/**
 * Runs all tasks for the current installation request.
 *
 * In the case of an interactive installation, all tasks will be attempted
 * until one is reached that has output which needs to be displayed to the
 * user, or until a page redirect is required. Otherwise, tasks will be
 * attempted until the installation is finished.
 *
 * @param $install_state
 *   An array of information about the current installation state. This is
 *   passed along to each task, so it can be modified if necessary.
 *
 * @return
 *   HTML output from the last completed task.
 */
function install_run_tasks(&$install_state) {
    do {
        // Obtain a list of tasks to perform. The list of tasks itself can be
        // dynamic (e.g., some might be defined by the installation profile,
        // which is not necessarily known until the earlier tasks have run),
        // so we regenerate the remaining tasks based on the installation state,
        // each time through the loop.
        $tasks_to_perform = install_tasks_to_perform($install_state);
        // Run the first task on the list.
        reset($tasks_to_perform);
        $task_name = key($tasks_to_perform);
        $task = array_shift($tasks_to_perform);
        $install_state['active_task'] = $task_name;
        $original_parameters = $install_state['parameters'];
        $output = install_run_task($task, $install_state);
        $install_state['parameters_changed'] = $install_state['parameters'] != $original_parameters;
        // Store this task as having been performed during the current request,
        // and save it to the database as completed, if we need to and if the
        // database is in a state that allows us to do so. Also mark the
        // installation as 'done' when we have run out of tasks.
        if (!$install_state['task_not_complete']) {
            $install_state['tasks_performed'][] = $task_name;
            $install_state['installation_finished'] = empty($tasks_to_perform);
            if ($install_state['database_tables_exist'] && ($task['run'] == INSTALL_TASK_RUN_IF_NOT_COMPLETED || $install_state['installation_finished'])) {
                variable_set('install_task', $install_state['installation_finished'] ? 'done' : $task_name);
            }
        }
        // Stop when there are no tasks left. In the case of an interactive
        // installation, also stop if we have some output to send to the browser,
        // the URL parameters have changed, or an end to the page request was
        // specifically called for.
        $finished = empty($tasks_to_perform) || $install_state['interactive'] && (isset($output) || $install_state['parameters_changed'] || $install_state['stop_page_request']);
    } while (!$finished);
    return $output;
}

/**
 * Runs an individual installation task.
 *
 * @param $task
 *   An array of information about the task to be run as returned by
 *   hook_install_tasks().
 * @param $install_state
 *   An array of information about the current installation state. This is
 *   passed in by reference so that it can be modified by the task.
 *
 * @return
 *   The output of the task function, if there is any.
 */
function install_run_task($task, &$install_state) {
    $function = $task['function'];
    if ($task['type'] == 'form') {
        require_once DRUPAL_ROOT . '/includes/form.inc';
        if ($install_state['interactive']) {
            // For interactive forms, build the form and ensure that it will not
            // redirect, since the installer handles its own redirection only after
            // marking the form submission task complete.
            $form_state = array(
                // We need to pass $install_state by reference in order for forms to
                // modify it, since the form API will use it in call_user_func_array(),
                // which requires that referenced variables be passed explicitly.
'build_info' => array(
                    'args' => array(
                        &$install_state,
                    ),
                ),
                'no_redirect' => TRUE,
            );
            $form = drupal_build_form($function, $form_state);
            // If a successful form submission did not occur, the form needs to be
            // rendered, which means the task is not complete yet.
            if (empty($form_state['executed'])) {
                $install_state['task_not_complete'] = TRUE;
                return drupal_render($form);
            }
            // Otherwise, return nothing so the next task will run in the same
            // request.
            return;
        }
        else {
            // For non-interactive forms, submit the form programmatically with the
            // values taken from the installation state. Throw an exception if any
            // errors were encountered.
            $form_state = array(
                'values' => !empty($install_state['forms'][$function]) ? $install_state['forms'][$function] : array(),
                // We need to pass $install_state by reference in order for forms to
                // modify it, since the form API will use it in call_user_func_array(),
                // which requires that referenced variables be passed explicitly.
'build_info' => array(
                    'args' => array(
                        &$install_state,
                    ),
                ),
            );
            drupal_form_submit($function, $form_state);
            $errors = form_get_errors();
            if (!empty($errors)) {
                throw new Exception(implode("\n", $errors));
            }
        }
    }
    elseif ($task['type'] == 'batch') {
        // Start a new batch based on the task function, if one is not running
        // already.
        $current_batch = variable_get('install_current_batch');
        if (!$install_state['interactive'] || !$current_batch) {
            $batch = $function($install_state);
            if (empty($batch)) {
                // If the task did some processing and decided no batch was necessary,
                // there is nothing more to do here.
                return;
            }
            batch_set($batch);
            // For interactive batches, we need to store the fact that this batch
            // task is currently running. Otherwise, we need to make sure the batch
            // will complete in one page request.
            if ($install_state['interactive']) {
                variable_set('install_current_batch', $function);
            }
            else {
                $batch =& batch_get();
                $batch['progressive'] = FALSE;
            }
            // Process the batch. For progressive batches, this will redirect.
            // Otherwise, the batch will complete.
            batch_process(install_redirect_url($install_state), install_full_redirect_url($install_state));
        }
        elseif ($current_batch == $function) {
            include_once DRUPAL_ROOT . '/includes/batch.inc';
            $output = _batch_page();
            // The task is complete when we try to access the batch page and receive
            // FALSE in return, since this means we are at a URL where we are no
            // longer requesting a batch ID.
            if ($output === FALSE) {
                // Return nothing so the next task will run in the same request.
                variable_del('install_current_batch');
                return;
            }
            else {
                // We need to force the page request to end if the task is not
                // complete, since the batch API sometimes prints JSON output
                // rather than returning a themed page.
                $install_state['task_not_complete'] = $install_state['stop_page_request'] = TRUE;
                return $output;
            }
        }
    }
    else {
        // For normal tasks, just return the function result, whatever it is.
        return $function($install_state);
    }
}

/**
 * Returns a list of tasks to perform during the current installation request.
 *
 * Note that the list of tasks can change based on the installation state as
 * the page request evolves (for example, if an installation profile hasn't
 * been selected yet, we don't yet know which profile tasks need to be run).
 *
 * You can override this using hook_install_tasks() or
 * hook_install_tasks_alter().
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A list of tasks to be performed, with associated metadata as returned by
 *   hook_install_tasks().
 */
function install_tasks_to_perform($install_state) {
    // Start with a list of all currently available tasks.
    $tasks = install_tasks($install_state);
    foreach ($tasks as $name => $task) {
        // Remove any tasks that were already performed or that never should run.
        // Also, if we started this page request with an indication of the last
        // task that was completed, skip that task and all those that come before
        // it, unless they are marked as always needing to run.
        if ($task['run'] == INSTALL_TASK_SKIP || in_array($name, $install_state['tasks_performed']) || !empty($install_state['completed_task']) && empty($completed_task_found) && $task['run'] != INSTALL_TASK_RUN_IF_REACHED) {
            unset($tasks[$name]);
        }
        if (!empty($install_state['completed_task']) && $name == $install_state['completed_task']) {
            $completed_task_found = TRUE;
        }
    }
    return $tasks;
}

/**
 * Returns a list of all tasks the installer currently knows about.
 *
 * This function will return tasks regardless of whether or not they are
 * intended to run on the current page request. However, the list can change
 * based on the installation state (for example, if an installation profile
 * hasn't been selected yet, we don't yet know which profile tasks will be
 * available).
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A list of tasks, with associated metadata.
 */
function install_tasks($install_state) {
    // Determine whether translation import tasks will need to be performed.
    $needs_translations = count($install_state['locales']) > 1 && !empty($install_state['parameters']['locale']) && $install_state['parameters']['locale'] != 'en';
    // Start with the core installation tasks that run before handing control
    // to the installation profile.
    $tasks = array(
        'install_select_profile' => array(
            'display_name' => st('Choose profile'),
            'display' => count($install_state['profiles']) != 1,
            'run' => INSTALL_TASK_RUN_IF_REACHED,
        ),
        'install_select_locale' => array(
            'display_name' => st('Choose language'),
            'run' => INSTALL_TASK_RUN_IF_REACHED,
        ),
        'install_load_profile' => array(
            'run' => INSTALL_TASK_RUN_IF_REACHED,
        ),
        'install_verify_requirements' => array(
            'display_name' => st('Verify requirements'),
        ),
        'install_settings_form' => array(
            'display_name' => st('Set up database'),
            'type' => 'form',
            'run' => $install_state['settings_verified'] ? INSTALL_TASK_SKIP : INSTALL_TASK_RUN_IF_NOT_COMPLETED,
        ),
        'install_system_module' => array(),
        'install_bootstrap_full' => array(
            'run' => INSTALL_TASK_RUN_IF_REACHED,
        ),
        'install_profile_modules' => array(
            'display_name' => count($install_state['profiles']) == 1 ? st('Install site') : st('Install profile'),
            'type' => 'batch',
        ),
        'install_import_locales' => array(
            'display_name' => st('Set up translations'),
            'display' => $needs_translations,
            'type' => 'batch',
            'run' => $needs_translations ? INSTALL_TASK_RUN_IF_NOT_COMPLETED : INSTALL_TASK_SKIP,
        ),
        'install_configure_form' => array(
            'display_name' => st('Configure site'),
            'type' => 'form',
        ),
    );
    // Now add any tasks defined by the installation profile.
    if (!empty($install_state['parameters']['profile'])) {
        // Load the profile install file, because it is not always loaded when
        // hook_install_tasks() is invoked (e.g. batch processing).
        $profile_install_file = DRUPAL_ROOT . '/profiles/' . $install_state['parameters']['profile'] . '/' . $install_state['parameters']['profile'] . '.install';
        if (file_exists($profile_install_file)) {
            include_once $profile_install_file;
        }
        $function = $install_state['parameters']['profile'] . '_install_tasks';
        if (function_exists($function)) {
            $result = $function($install_state);
            if (is_array($result)) {
                $tasks += $result;
            }
        }
    }
    // Finish by adding the remaining core tasks.
    $tasks += array(
        'install_import_locales_remaining' => array(
            'display_name' => st('Finish translations'),
            'display' => $needs_translations,
            'type' => 'batch',
            'run' => $needs_translations ? INSTALL_TASK_RUN_IF_NOT_COMPLETED : INSTALL_TASK_SKIP,
        ),
        'install_finished' => array(
            'display_name' => st('Finished'),
        ),
    );
    // Allow the installation profile to modify the full list of tasks.
    if (!empty($install_state['parameters']['profile'])) {
        $profile_file = DRUPAL_ROOT . '/profiles/' . $install_state['parameters']['profile'] . '/' . $install_state['parameters']['profile'] . '.profile';
        if (file_exists($profile_file)) {
            include_once $profile_file;
            $function = $install_state['parameters']['profile'] . '_install_tasks_alter';
            if (function_exists($function)) {
                $function($tasks, $install_state);
            }
        }
    }
    // Fill in default parameters for each task before returning the list.
    foreach ($tasks as $task_name => &$task) {
        $task += array(
            'display_name' => NULL,
            'display' => !empty($task['display_name']),
            'type' => 'normal',
            'run' => INSTALL_TASK_RUN_IF_NOT_COMPLETED,
            'function' => $task_name,
        );
    }
    return $tasks;
}

/**
 * Returns a list of tasks that should be displayed to the end user.
 *
 * The output of this function is a list suitable for sending to
 * theme_task_list().
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A list of tasks, with keys equal to the machine-readable task name and
 *   values equal to the name that should be displayed.
 *
 * @see theme_task_list()
 */
function install_tasks_to_display($install_state) {
    $displayed_tasks = array();
    foreach (install_tasks($install_state) as $name => $task) {
        if ($task['display']) {
            $displayed_tasks[$name] = $task['display_name'];
        }
    }
    return $displayed_tasks;
}

/**
 * Returns the URL that should be redirected to during an installation request.
 *
 * The output of this function is suitable for sending to install_goto().
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   The URL to redirect to.
 *
 * @see install_full_redirect_url()
 */
function install_redirect_url($install_state) {
    return 'install.php?' . drupal_http_build_query($install_state['parameters']);
}

/**
 * Returns the complete URL redirected to during an installation request.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   The complete URL to redirect to.
 *
 * @see install_redirect_url()
 */
function install_full_redirect_url($install_state) {
    global $base_url;
    return $base_url . '/' . install_redirect_url($install_state);
}

/**
 * Displays themed installer output and ends the page request.
 *
 * Installation tasks should use drupal_set_title() to set the desired page
 * title, but otherwise this function takes care of theming the overall page
 * output during every step of the installation.
 *
 * @param $output
 *   The content to display on the main part of the page.
 * @param $install_state
 *   An array of information about the current installation state.
 */
function install_display_output($output, $install_state) {
    drupal_page_header();
    // Prevent install.php from being indexed when installed in a sub folder.
    // robots.txt rules are not read if the site is within domain.com/subfolder
    // resulting in /subfolder/install.php being found through search engines.
    // When settings.php is writeable this can be used via an external database
    // leading a malicious user to gain php access to the server.
    $noindex_meta_tag = array(
        '#tag' => 'meta',
        '#attributes' => array(
            'name' => 'robots',
            'content' => 'noindex, nofollow',
        ),
    );
    drupal_add_html_head($noindex_meta_tag, 'install_meta_robots');
    // Only show the task list if there is an active task; otherwise, the page
    // request has ended before tasks have even been started, so there is nothing
    // meaningful to show.
    if (isset($install_state['active_task'])) {
        // Let the theming function know when every step of the installation has
        // been completed.
        $active_task = $install_state['installation_finished'] ? NULL : $install_state['active_task'];
        drupal_add_region_content('sidebar_first', theme('task_list', array(
            'items' => install_tasks_to_display($install_state),
            'active' => $active_task,
        )));
    }
    print theme('install_page', array(
        'content' => $output,
    ));
    exit;
}

/**
 * Verifies the requirements for installing Drupal.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A themed status report, or an exception if there are requirement errors.
 *   If there are only requirement warnings, a themed status report is shown
 *   initially, but the user is allowed to bypass it by providing 'continue=1'
 *   in the URL. Otherwise, no output is returned, so that the next task can be
 *   run in the same page request.
 */
function install_verify_requirements(&$install_state) {
    // Check the installation requirements for Drupal and this profile.
    $requirements = install_check_requirements($install_state);
    // Verify existence of all required modules.
    $requirements += drupal_verify_profile($install_state);
    // Check the severity of the requirements reported.
    $severity = drupal_requirements_severity($requirements);
    // If there are errors, always display them. If there are only warnings, skip
    // them if the user has provided a URL parameter acknowledging the warnings
    // and indicating a desire to continue anyway. See drupal_requirements_url().
    if ($severity == REQUIREMENT_ERROR || $severity == REQUIREMENT_WARNING && empty($install_state['parameters']['continue'])) {
        if ($install_state['interactive']) {
            drupal_set_title(st('Requirements problem'));
            $status_report = theme('status_report', array(
                'requirements' => $requirements,
            ));
            $status_report .= st('Check the error messages and <a href="!url">proceed with the installation</a>.', array(
                '!url' => check_url(drupal_requirements_url($severity)),
            ));
            return $status_report;
        }
        else {
            // Throw an exception showing any unmet requirements.
            $failures = array();
            foreach ($requirements as $requirement) {
                // Skip warnings altogether for non-interactive installations; these
                // proceed in a single request so there is no good opportunity (and no
                // good method) to warn the user anyway.
                if (isset($requirement['severity']) && $requirement['severity'] == REQUIREMENT_ERROR) {
                    $failures[] = $requirement['title'] . ': ' . $requirement['value'] . "\n\n" . $requirement['description'];
                }
            }
            if (!empty($failures)) {
                throw new Exception(implode("\n\n", $failures));
            }
        }
    }
}

/**
 * Installation task; install the Drupal system module.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 */
function install_system_module(&$install_state) {
    // Install system.module.
    drupal_install_system();
    // Call file_ensure_htaccess() to ensure that all of Drupal's standard
    // directories (e.g., the public and private files directories) have
    // appropriate .htaccess files. These directories will have already been
    // created by this point in the installer, since Drupal creates them during
    // the install_verify_requirements() task. Note that we cannot call
    // file_ensure_htaccess() any earlier than this, since it relies on
    // system.module in order to work.
    file_ensure_htaccess();
    // Enable the user module so that sessions can be recorded during the
    // upcoming bootstrap step.
    module_enable(array(
        'user',
    ), FALSE);
    // Save the list of other modules to install for the upcoming tasks.
    // variable_set() can be used now that system.module is installed.
    $modules = $install_state['profile_info']['dependencies'];
    // The installation profile is also a module, which needs to be installed
    // after all the dependencies have been installed.
    $modules[] = drupal_get_profile();
    variable_set('install_profile_modules', array_diff($modules, array(
        'system',
    )));
    $install_state['database_tables_exist'] = TRUE;
    // Prevent the hook_requirements() check from telling us to convert the
    // database to utf8mb4.
    $connection = Database::getConnection();
    if ($connection->utf8mb4IsConfigurable() && $connection->utf8mb4IsActive()) {
        variable_set('drupal_all_databases_are_utf8mb4', TRUE);
    }
}

/**
 * Verifies and returns the last installation task that was completed.
 *
 * @return
 *   The last completed task, if there is one. An exception is thrown if Drupal
 *   is already installed.
 */
function install_verify_completed_task() {
    try {
        if ($result = db_query("SELECT value FROM {variable} WHERE name = :name", array(
            'name' => 'install_task',
        ))) {
            $task = unserialize($result->fetchField());
        }
    } catch (Exception $e) {
    }
    if (isset($task)) {
        if ($task == 'done') {
            throw new Exception(install_already_done_error());
        }
        return $task;
    }
}

/**
 * Verifies the existing settings in settings.php.
 */
function install_verify_settings() {
    global $databases;
    // Verify existing settings (if any).
    if (!empty($databases) && install_verify_pdo()) {
        $database = $databases['default']['default'];
        drupal_static_reset('conf_path');
        $settings_file = './' . conf_path(FALSE) . '/settings.php';
        $errors = install_database_errors($database, $settings_file);
        if (empty($errors)) {
            return TRUE;
        }
    }
    return FALSE;
}

/**
 * Verifies the PDO library.
 */
function install_verify_pdo() {
    // PDO was moved to PHP core in 5.2.0, but the old extension (targeting 5.0
    // and 5.1) is still available from PECL, and can still be built without
    // errors. To verify that the correct version is in use, we check the
    // PDO::ATTR_DEFAULT_FETCH_MODE constant, which is not available in the
    // PECL extension.
    return extension_loaded('pdo') && defined('PDO::ATTR_DEFAULT_FETCH_MODE');
}

/**
 * Form constructor for a form to configure and rewrite settings.php.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @see install_settings_form_validate()
 * @see install_settings_form_submit()
 * @ingroup forms
 */
function install_settings_form($form, &$form_state, &$install_state) {
    global $databases;
    $profile = $install_state['parameters']['profile'];
    $install_locale = $install_state['parameters']['locale'];
    drupal_static_reset('conf_path');
    $conf_path = './' . conf_path(FALSE);
    $settings_file = $conf_path . '/settings.php';
    $database = isset($databases['default']['default']) ? $databases['default']['default'] : array();
    drupal_set_title(st('Database configuration'));
    $drivers = drupal_get_database_types();
    $drivers_keys = array_keys($drivers);
    $form['driver'] = array(
        '#type' => 'radios',
        '#title' => st('Database type'),
        '#required' => TRUE,
        '#default_value' => !empty($database['driver']) ? $database['driver'] : current($drivers_keys),
        '#description' => st('The type of database your @drupal data will be stored in.', array(
            '@drupal' => drupal_install_profile_distribution_name(),
        )),
    );
    if (count($drivers) == 1) {
        $form['driver']['#disabled'] = TRUE;
        $form['driver']['#description'] .= ' ' . st('Your PHP configuration only supports a single database type, so it has been automatically selected.');
    }
    // Add driver specific configuration options.
    foreach ($drivers as $key => $driver) {
        $form['driver']['#options'][$key] = $driver->name();
        $form['settings'][$key] = $driver->getFormOptions($database);
        $form['settings'][$key]['#prefix'] = '<h2 class="js-hide">' . st('@driver_name settings', array(
            '@driver_name' => $driver->name(),
        )) . '</h2>';
        $form['settings'][$key]['#type'] = 'container';
        $form['settings'][$key]['#tree'] = TRUE;
        $form['settings'][$key]['advanced_options']['#parents'] = array(
            $key,
        );
        $form['settings'][$key]['#states'] = array(
            'visible' => array(
                ':input[name=driver]' => array(
                    'value' => $key,
                ),
            ),
        );
    }
    $form['actions'] = array(
        '#type' => 'actions',
    );
    $form['actions']['save'] = array(
        '#type' => 'submit',
        '#value' => st('Save and continue'),
        '#limit_validation_errors' => array(
            array(
                'driver',
            ),
            array(
                isset($form_state['input']['driver']) ? $form_state['input']['driver'] : current($drivers_keys),
            ),
        ),
        '#submit' => array(
            'install_settings_form_submit',
        ),
    );
    $form['errors'] = array();
    $form['settings_file'] = array(
        '#type' => 'value',
        '#value' => $settings_file,
    );
    return $form;
}

/**
 * Form validation handler for install_settings_form().
 *
 * @see install_settings_form_submit()
 */
function install_settings_form_validate($form, &$form_state) {
    $driver = $form_state['values']['driver'];
    $database = $form_state['values'][$driver];
    $database['driver'] = $driver;
    // TODO: remove when PIFR will be updated to use 'db_prefix' instead of
    // 'prefix' in the database settings form.
    $database['prefix'] = $database['db_prefix'];
    unset($database['db_prefix']);
    $form_state['storage']['database'] = $database;
    $errors = install_database_errors($database, $form_state['values']['settings_file']);
    foreach ($errors as $name => $message) {
        form_set_error($name, $message);
    }
}

/**
 * Checks a database connection and returns any errors.
 */
function install_database_errors($database, $settings_file) {
    global $databases;
    $errors = array();
    // Check database type.
    $database_types = drupal_get_database_types();
    $driver = $database['driver'];
    if (!isset($database_types[$driver])) {
        $errors['driver'] = st("In your %settings_file file you have configured @drupal to use a %driver server, however your PHP installation currently does not support this database type.", array(
            '%settings_file' => $settings_file,
            '@drupal' => drupal_install_profile_distribution_name(),
            '%driver' => $driver,
        ));
    }
    else {
        // Run driver specific validation
        $errors += $database_types[$driver]->validateDatabaseSettings($database);
        // Run tasks associated with the database type. Any errors are caught in the
        // calling function.
        $databases['default']['default'] = $database;
        // Just changing the global doesn't get the new information processed.
        // We tell tell the Database class to re-parse $databases.
        Database::parseConnectionInfo();
        try {
            db_run_tasks($driver);
        } catch (DatabaseTaskException $e) {
            // These are generic errors, so we do not have any specific key of the
            // database connection array to attach them to; therefore, we just put
            // them in the error array with standard numeric keys.
            $errors[$driver . '][0'] = $e->getMessage();
        }
    }
    return $errors;
}

/**
 * Form submission handler for install_settings_form().
 *
 * @see install_settings_form_validate()
 */
function install_settings_form_submit($form, &$form_state) {
    global $install_state;
    // Update global settings array and save.
    $settings['databases'] = array(
        'value' => array(
            'default' => array(
                'default' => $form_state['storage']['database'],
            ),
        ),
        'required' => TRUE,
    );
    $settings['drupal_hash_salt'] = array(
        'value' => drupal_random_key(),
        'required' => TRUE,
    );
    drupal_rewrite_settings($settings);
    // Indicate that the settings file has been verified, and check the database
    // for the last completed task, now that we have a valid connection. This
    // last step is important since we want to trigger an error if the new
    // database already has Drupal installed.
    $install_state['settings_verified'] = TRUE;
    $install_state['completed_task'] = install_verify_completed_task();
}

/**
 * Finds all .profile files.
 */
function install_find_profiles() {
    return file_scan_directory('./profiles', '/\\.profile$/', array(
        'key' => 'name',
    ));
}

/**
 * Selects which profile to install.
 *
 * @param $install_state
 *   An array of information about the current installation state. The chosen
 *   profile will be added here, if it was not already selected previously, as
 *   will a list of all available profiles.
 *
 * @return
 *   For interactive installations, a form allowing the profile to be selected,
 *   if the user has a choice that needs to be made. Otherwise, an exception is
 *   thrown if a profile cannot be chosen automatically.
 */
function install_select_profile(&$install_state) {
    $install_state['profiles'] += install_find_profiles();
    if (empty($install_state['parameters']['profile'])) {
        // Try to find a profile.
        $profile = _install_select_profile($install_state['profiles']);
        if (empty($profile)) {
            // We still don't have a profile, so display a form for selecting one.
            // Only do this in the case of interactive installations, since this is
            // not a real form with submit handlers (the database isn't even set up
            // yet), rather just a convenience method for setting parameters in the
            // URL.
            if ($install_state['interactive']) {
                include_once DRUPAL_ROOT . '/includes/form.inc';
                drupal_set_title(st('Select an installation profile'));
                $form = drupal_get_form('install_select_profile_form', $install_state['profiles']);
                return drupal_render($form);
            }
            else {
                throw new Exception(install_no_profile_error());
            }
        }
        else {
            $install_state['parameters']['profile'] = $profile;
        }
    }
}

/**
 * Selects an installation profile.
 *
 * A profile will be selected if:
 * - Only one profile is available,
 * - A profile was submitted through $_POST,
 * - Exactly one of the profiles is marked as "exclusive".
 * If multiple profiles are marked as "exclusive" then no profile will be
 * selected.
 *
 * @param array $profiles
 *   An associative array of profiles with the machine-readable names as keys.
 *
 * @return
 *   The machine-readable name of the selected profile or NULL if no profile was
 *   selected.
 */
function _install_select_profile($profiles) {
    if (sizeof($profiles) == 0) {
        throw new Exception(install_no_profile_error());
    }
    // Don't need to choose profile if only one available.
    if (sizeof($profiles) == 1) {
        $profile = array_pop($profiles);
        // TODO: is this right?
        require_once DRUPAL_ROOT . '/' . $profile->uri;
        return $profile->name;
    }
    else {
        foreach ($profiles as $profile) {
            if (!empty($_POST['profile']) && $_POST['profile'] == $profile->name) {
                return $profile->name;
            }
        }
    }
    // Check for a profile marked as "exclusive" and ensure that only one
    // profile is marked as such.
    $exclusive_profile = NULL;
    foreach ($profiles as $profile) {
        $profile_info = install_profile_info($profile->name);
        if (!empty($profile_info['exclusive'])) {
            if (empty($exclusive_profile)) {
                $exclusive_profile = $profile->name;
            }
            else {
                // We found a second "exclusive" profile. There's no way to choose
                // between them, so we ignore the property.
                return;
            }
        }
    }
    return $exclusive_profile;
}

/**
 * Form constructor for the profile selection form.
 *
 * @param $form_state
 *   Array of metadata about state of form processing.
 * @param $profile_files
 *   Array of .profile files, as returned from file_scan_directory().
 *
 * @ingroup forms
 */
function install_select_profile_form($form, &$form_state, $profile_files) {
    $profiles = array();
    $names = array();
    foreach ($profile_files as $profile) {
        // TODO: is this right?
        include_once DRUPAL_ROOT . '/' . $profile->uri;
        $details = install_profile_info($profile->name);
        // Don't show hidden profiles. This is used by to hide the testing profile,
        // which only exists to speed up test runs.
        if ($details['hidden'] === TRUE) {
            continue;
        }
        $profiles[$profile->name] = $details;
        // Determine the name of the profile; default to file name if defined name
        // is unspecified.
        $name = isset($details['name']) ? $details['name'] : $profile->name;
        $names[$profile->name] = $name;
    }
    // Display radio buttons alphabetically by human-readable name, but always
    // put the core profiles first (if they are present in the filesystem).
    natcasesort($names);
    if (isset($names['minimal'])) {
        // If the expert ("Minimal") core profile is present, put it in front of
        // any non-core profiles rather than including it with them alphabetically,
        // since the other profiles might be intended to group together in a
        // particular way.
        $names = array(
            'minimal' => $names['minimal'],
        ) + $names;
    }
    if (isset($names['standard'])) {
        // If the default ("Standard") core profile is present, put it at the very
        // top of the list. This profile will have its radio button pre-selected,
        // so we want it to always appear at the top.
        $names = array(
            'standard' => $names['standard'],
        ) + $names;
    }
    foreach ($names as $profile => $name) {
        $form['profile'][$name] = array(
            '#type' => 'radio',
            '#value' => 'standard',
            '#return_value' => $profile,
            '#title' => $name,
            '#description' => isset($profiles[$profile]['description']) ? $profiles[$profile]['description'] : '',
            '#parents' => array(
                'profile',
            ),
        );
    }
    $form['actions'] = array(
        '#type' => 'actions',
    );
    $form['actions']['submit'] = array(
        '#type' => 'submit',
        '#value' => st('Save and continue'),
    );
    return $form;
}

/**
 * Find all .po files for the current profile.
 */
function install_find_locales($profilename) {
    $locales = file_scan_directory('./profiles/' . $profilename . '/translations', '/\\.po$/', array(
        'recurse' => FALSE,
    ));
    array_unshift($locales, (object) array(
        'name' => 'en',
    ));
    foreach ($locales as $key => $locale) {
        // The locale (file name) might be drupal-7.2.cs.po instead of cs.po.
        $locales[$key]->langcode = preg_replace('!^(.+\\.)?([^\\.]+)$!', '\\2', $locale->name);
        // Language codes cannot exceed 12 characters to fit into the {languages}
        // table.
        if (strlen($locales[$key]->langcode) > 12) {
            unset($locales[$key]);
        }
    }
    return $locales;
}

/**
 * Installation task; select which locale to use for the current profile.
 *
 * @param $install_state
 *   An array of information about the current installation state. The chosen
 *   locale will be added here, if it was not already selected previously, as
 *   will a list of all available locales.
 *
 * @return
 *   For interactive installations, a form or other page output allowing the
 *   locale to be selected or providing information about locale selection, if
 *   a locale has not been chosen. Otherwise, an exception is thrown if a
 *   locale cannot be chosen automatically.
 */
function install_select_locale(&$install_state) {
    // Find all available locales.
    $profilename = $install_state['parameters']['profile'];
    $locales = install_find_locales($profilename);
    $install_state['locales'] += $locales;
    if (!empty($_POST['locale'])) {
        foreach ($locales as $locale) {
            if ($_POST['locale'] == $locale->langcode) {
                $install_state['parameters']['locale'] = $locale->langcode;
                return;
            }
        }
    }
    if (empty($install_state['parameters']['locale'])) {
        // If only the built-in (English) language is available, and we are
        // performing an interactive installation, inform the user that the
        // installer can be localized. Otherwise we assume the user knows what he
        // is doing.
        if (count($locales) == 1) {
            if ($install_state['interactive']) {
                drupal_set_title(st('Choose language'));
                if (!empty($install_state['parameters']['localize'])) {
                    $output = '<p>Follow these steps to translate Drupal into your language:</p>';
                    $output .= '<ol>';
                    $output .= '<li>Download a translation from the <a href="http://localize.drupal.org/download" target="_blank">translation server</a>.</li>';
                    $output .= '<li>Place it into the following directory:
<pre>
/profiles/' . $profilename . '/translations/
</pre></li>';
                    $output .= '</ol>';
                    $output .= '<p>For more information on installing Drupal in different languages, visit the <a href="http://drupal.org/localize" target="_blank">drupal.org handbook page</a>.</p>';
                    $output .= '<p>How should the installation continue?</p>';
                    $output .= '<ul>';
                    $output .= '<li><a href="install.php?profile=' . $profilename . '">Reload the language selection page after adding translations</a></li>';
                    $output .= '<li><a href="install.php?profile=' . $profilename . '&amp;locale=en">Continue installation in English</a></li>';
                    $output .= '</ul>';
                }
                else {
                    include_once DRUPAL_ROOT . '/includes/form.inc';
                    $elements = drupal_get_form('install_select_locale_form', $locales, $profilename);
                    $output = drupal_render($elements);
                }
                return $output;
            }
            // One language, but not an interactive installation. Assume the user
            // knows what he is doing.
            $locale = current($locales);
            $install_state['parameters']['locale'] = $locale->name;
            return;
        }
        else {
            // Allow profile to pre-select the language, skipping the selection.
            $function = $profilename . '_profile_details';
            if (function_exists($function)) {
                $details = $function();
                if (isset($details['language'])) {
                    foreach ($locales as $locale) {
                        if ($details['language'] == $locale->name) {
                            $install_state['parameters']['locale'] = $locale->name;
                            return;
                        }
                    }
                }
            }
            // We still don't have a locale, so display a form for selecting one.
            // Only do this in the case of interactive installations, since this is
            // not a real form with submit handlers (the database isn't even set up
            // yet), rather just a convenience method for setting parameters in the
            // URL.
            if ($install_state['interactive']) {
                drupal_set_title(st('Choose language'));
                include_once DRUPAL_ROOT . '/includes/form.inc';
                $elements = drupal_get_form('install_select_locale_form', $locales, $profilename);
                return drupal_render($elements);
            }
            else {
                throw new Exception(st('Sorry, you must select a language to continue the installation.'));
            }
        }
    }
}

/**
 * Form constructor for the language selection form.
 *
 * @ingroup forms
 */
function install_select_locale_form($form, &$form_state, $locales, $profilename) {
    include_once DRUPAL_ROOT . '/includes/iso.inc';
    $languages = _locale_get_predefined_list();
    foreach ($locales as $locale) {
        $name = $locale->langcode;
        if (isset($languages[$name])) {
            $name = $languages[$name][0] . (isset($languages[$name][1]) ? ' ' . st('(@language)', array(
                '@language' => $languages[$name][1],
            )) : '');
        }
        $form['locale'][$locale->langcode] = array(
            '#type' => 'radio',
            '#return_value' => $locale->langcode,
            '#default_value' => $locale->langcode == 'en' ? 'en' : '',
            '#title' => $name . ($locale->langcode == 'en' ? ' ' . st('(built-in)') : ''),
            '#parents' => array(
                'locale',
            ),
        );
    }
    if (count($locales) == 1) {
        $form['help'] = array(
            '#markup' => '<p><a href="install.php?profile=' . $profilename . '&amp;localize=true">' . st('Learn how to install Drupal in other languages') . '</a></p>',
        );
    }
    $form['actions'] = array(
        '#type' => 'actions',
    );
    $form['actions']['submit'] = array(
        '#type' => 'submit',
        '#value' => st('Save and continue'),
    );
    return $form;
}

/**
 * Indicates that there are no profiles available.
 */
function install_no_profile_error() {
    drupal_set_title(st('No profiles available'));
    return st('We were unable to find any installation profiles. Installation profiles tell us what modules to enable and what schema to install in the database. A profile is necessary to continue with the installation process.');
}

/**
 * Indicates that Drupal has already been installed.
 */
function install_already_done_error() {
    global $base_url;
    drupal_set_title(st('Drupal already installed'));
    return st('<ul><li>To start over, you must empty your existing database.</li><li>To install to a different database, edit the appropriate <em>settings.php</em> file in the <em>sites</em> folder.</li><li>To upgrade an existing installation, proceed to the <a href="@base-url/update.php">update script</a>.</li><li>View your <a href="@base-url">existing site</a>.</li></ul>', array(
        '@base-url' => $base_url,
    ));
}

/**
 * Loads information about the chosen profile during installation.
 *
 * @param $install_state
 *   An array of information about the current installation state. The loaded
 *   profile information will be added here, or an exception will be thrown if
 *   the profile cannot be loaded.
 */
function install_load_profile(&$install_state) {
    $profile_file = DRUPAL_ROOT . '/profiles/' . $install_state['parameters']['profile'] . '/' . $install_state['parameters']['profile'] . '.profile';
    if (file_exists($profile_file)) {
        include_once $profile_file;
        $install_state['profile_info'] = install_profile_info($install_state['parameters']['profile'], $install_state['parameters']['locale']);
    }
    else {
        throw new Exception(st('Sorry, the profile you have chosen cannot be loaded.'));
    }
}

/**
 * Performs a full bootstrap of Drupal during installation.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 */
function install_bootstrap_full(&$install_state) {
    drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
}

/**
 * Installs required modules via a batch process.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   The batch definition.
 */
function install_profile_modules(&$install_state) {
    $modules = variable_get('install_profile_modules', array());
    $files = system_rebuild_module_data();
    variable_del('install_profile_modules');
    // Always install required modules first. Respect the dependencies between
    // the modules.
    $required = array();
    $non_required = array();
    // Although the profile module is marked as required, it needs to go after
    // every dependency, including non-required ones. So clear its required
    // flag for now to allow it to install late.
    $files[$install_state['parameters']['profile']]->info['required'] = FALSE;
    // Add modules that other modules depend on.
    foreach ($modules as $module) {
        if ($files[$module]->requires) {
            $modules = array_merge($modules, array_keys($files[$module]->requires));
        }
    }
    $modules = array_unique($modules);
    foreach ($modules as $module) {
        if (!empty($files[$module]->info['required'])) {
            $required[$module] = $files[$module]->sort;
        }
        else {
            $non_required[$module] = $files[$module]->sort;
        }
    }
    arsort($required);
    arsort($non_required);
    $operations = array();
    foreach ($required + $non_required as $module => $weight) {
        $operations[] = array(
            '_install_module_batch',
            array(
                $module,
                $files[$module]->info['name'],
            ),
        );
    }
    $batch = array(
        'operations' => $operations,
        'title' => st('Installing @drupal', array(
            '@drupal' => drupal_install_profile_distribution_name(),
        )),
        'error_message' => st('The installation has encountered an error.'),
        'finished' => '_install_profile_modules_finished',
    );
    return $batch;
}

/**
 * Imports languages via a batch process during installation.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   The batch definition, if there are language files to import.
 */
function install_import_locales(&$install_state) {
    include_once DRUPAL_ROOT . '/includes/locale.inc';
    $install_locale = $install_state['parameters']['locale'];
    include_once DRUPAL_ROOT . '/includes/iso.inc';
    $predefined = _locale_get_predefined_list();
    if (!isset($predefined[$install_locale])) {
        // Drupal does not know about this language, so we prefill its values with
        // our best guess. The user will be able to edit afterwards.
        locale_add_language($install_locale, $install_locale, $install_locale, LANGUAGE_LTR, '', '', TRUE, TRUE);
    }
    else {
        // A known predefined language, details will be filled in properly.
        locale_add_language($install_locale, NULL, NULL, NULL, '', '', TRUE, TRUE);
    }
    // Collect files to import for this language.
    $batch = locale_batch_by_language($install_locale, NULL);
    if (!empty($batch)) {
        // Remember components we cover in this batch set.
        variable_set('install_locale_batch_components', $batch['#components']);
        return $batch;
    }
}

/**
 * Form constructor for a form to configure the new site.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @see install_configure_form_validate()
 * @see install_configure_form_submit()
 * @ingroup forms
 */
function install_configure_form($form, &$form_state, &$install_state) {
    drupal_set_title(st('Configure site'));
    // Warn about settings.php permissions risk
    $settings_dir = conf_path();
    $settings_file = $settings_dir . '/settings.php';
    // Check that $_POST is empty so we only show this message when the form is
    // first displayed, not on the next page after it is submitted. (We do not
    // want to repeat it multiple times because it is a general warning that is
    // not related to the rest of the installation process; it would also be
    // especially out of place on the last page of the installer, where it would
    // distract from the message that the Drupal installation has completed
    // successfully.)
    $skip_permissions_hardening = variable_get('skip_permissions_hardening', FALSE);
    // Allow system administrators to ignore permissions hardening for the site
    // directory. This allows additional files in the site directory to be
    // updated when they are managed in a version control system.
    if (!$skip_permissions_hardening) {
        if (empty($_POST) && (!drupal_verify_install_file(DRUPAL_ROOT . '/' . $settings_file, FILE_EXIST | FILE_READABLE | FILE_NOT_WRITABLE) || !drupal_verify_install_file(DRUPAL_ROOT . '/' . $settings_dir, FILE_NOT_WRITABLE, 'dir'))) {
            drupal_set_message(st('All necessary changes to %dir and %file have been made, so you should remove write permissions to them now in order to avoid security risks. If you are unsure how to do so, consult the <a href="@handbook_url">online handbook</a>.', array(
                '%dir' => $settings_dir,
                '%file' => $settings_file,
                '@handbook_url' => 'http://drupal.org/server-permissions',
            )), 'warning');
        }
    }
    drupal_add_js(drupal_get_path('module', 'system') . '/system.js');
    // Add JavaScript time zone detection.
    drupal_add_js('misc/timezone.js');
    // We add these strings as settings because JavaScript translation does not
    // work during installation.
    drupal_add_js(array(
        'copyFieldValue' => array(
            'edit-site-mail' => array(
                'edit-account-mail',
            ),
        ),
    ), 'setting');
    drupal_add_js('jQuery(function () { Drupal.cleanURLsInstallCheck(); });', 'inline');
    // Add JS to show / hide the 'Email administrator about site updates' elements
    drupal_add_js('jQuery(function () { Drupal.hideEmailAdministratorCheckbox() });', 'inline');
    // Build menu to allow clean URL check.
    menu_rebuild();
    // Cache a fully-built schema. This is necessary for any invocation of
    // index.php because: (1) setting cache table entries requires schema
    // information, (2) that occurs during bootstrap before any module are
    // loaded, so (3) if there is no cached schema, drupal_get_schema() will
    // try to generate one but with no loaded modules will return nothing.
    //
    // This logically could be done during the 'install_finished' task, but the
    // clean URL check requires it now.
    drupal_get_schema(NULL, TRUE);
    // Return the form.
    return _install_configure_form($form, $form_state, $install_state);
}

/**
 * Installation task; import remaining languages via a batch process.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   The batch definition, if there are language files to import.
 */
function install_import_locales_remaining(&$install_state) {
    include_once DRUPAL_ROOT . '/includes/locale.inc';
    // Collect files to import for this language. Skip components already covered
    // in the initial batch set.
    $install_locale = $install_state['parameters']['locale'];
    $batch = locale_batch_by_language($install_locale, NULL, variable_get('install_locale_batch_components', array()));
    // Remove temporary variable.
    variable_del('install_locale_batch_components');
    return $batch;
}

/**
 * Finishes importing files at end of installation.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @return
 *   A message informing the user that the installation is complete.
 */
function install_finished(&$install_state) {
    drupal_set_title(st('@drupal installation complete', array(
        '@drupal' => drupal_install_profile_distribution_name(),
    )), PASS_THROUGH);
    $messages = drupal_set_message();
    $output = '<p>' . st('Congratulations, you installed @drupal!', array(
        '@drupal' => drupal_install_profile_distribution_name(),
    )) . '</p>';
    $output .= '<p>' . (isset($messages['error']) ? st('Review the messages above before visiting <a href="@url">your new site</a>.', array(
        '@url' => url(''),
    )) : st('<a href="@url">Visit your new site</a>.', array(
        '@url' => url(''),
    ))) . '</p>';
    // Flush all caches to ensure that any full bootstraps during the installer
    // do not leave stale cached data, and that any content types or other items
    // registered by the installation profile are registered correctly.
    drupal_flush_all_caches();
    // Remember the profile which was used.
    variable_set('install_profile', drupal_get_profile());
    // Installation profiles are always loaded last
    db_update('system')->fields(array(
        'weight' => 1000,
    ))
        ->condition('type', 'module')
        ->condition('name', drupal_get_profile())
        ->execute();
    // Cache a fully-built schema.
    drupal_get_schema(NULL, TRUE);
    // Run cron to populate update status tables (if available) so that users
    // will be warned if they've installed an out of date Drupal version.
    // Will also trigger indexing of profile-supplied content or feeds.
    drupal_cron_run();
    return $output;
}

/**
 * Implements callback_batch_operation().
 *
 * Performs batch installation of modules.
 */
function _install_module_batch($module, $module_name, &$context) {
    // Install and enable the module right away, so that the module will be
    // loaded by drupal_bootstrap in subsequent batch requests, and other
    // modules possibly depending on it can safely perform their installation
    // steps.
    module_enable(array(
        $module,
    ), FALSE);
    $context['results'][] = $module;
    $context['message'] = st('Installed %module module.', array(
        '%module' => $module_name,
    ));
}

/**
 * Implements callback_batch_finished().
 *
 * 'Finished' callback for module installation batch.
 */
function _install_profile_modules_finished($success, $results, $operations) {
    // Flush all caches to complete the module installation process. Subsequent
    // installation tasks will now have full access to the profile's modules.
    drupal_flush_all_caches();
}

/**
 * Checks installation requirements and reports any errors.
 */
function install_check_requirements($install_state) {
    $profile = $install_state['parameters']['profile'];
    // Check the profile requirements.
    $requirements = drupal_check_profile($profile);
    // If Drupal is not set up already, we need to create a settings file.
    if (!$install_state['settings_verified']) {
        $writable = FALSE;
        $conf_path = './' . conf_path(FALSE, TRUE);
        $settings_file = $conf_path . '/settings.php';
        $default_settings_file = './sites/default/default.settings.php';
        $file = $conf_path;
        $exists = FALSE;
        // Verify that the directory exists.
        if (drupal_verify_install_file($conf_path, FILE_EXIST, 'dir')) {
            // Check if a settings.php file already exists.
            $file = $settings_file;
            if (drupal_verify_install_file($settings_file, FILE_EXIST)) {
                // If it does, make sure it is writable.
                $writable = drupal_verify_install_file($settings_file, FILE_READABLE | FILE_WRITABLE);
                $exists = TRUE;
            }
        }
        // If default.settings.php does not exist, or is not readable, throw an
        // error.
        if (!drupal_verify_install_file($default_settings_file, FILE_EXIST | FILE_READABLE)) {
            $requirements['default settings file exists'] = array(
                'title' => st('Default settings file'),
                'value' => st('The default settings file does not exist.'),
                'severity' => REQUIREMENT_ERROR,
                'description' => st('The @drupal installer requires that the %default-file file not be modified in any way from the original download.', array(
                    '@drupal' => drupal_install_profile_distribution_name(),
                    '%default-file' => $default_settings_file,
                )),
            );
        }
        elseif (!$exists) {
            $copied = drupal_verify_install_file($conf_path, FILE_EXIST | FILE_WRITABLE, 'dir') && @copy($default_settings_file, $settings_file);
            if ($copied) {
                // If the new settings file has the same owner as default.settings.php,
                // this means default.settings.php is owned by the webserver user.
                // This is an inherent security weakness because it allows a malicious
                // webserver process to append arbitrary PHP code and then execute it.
                // However, it is also a common configuration on shared hosting, and
                // there is nothing Drupal can do to prevent it. In this situation,
                // having settings.php also owned by the webserver does not introduce
                // any additional security risk, so we keep the file in place.
                if (fileowner($default_settings_file) === fileowner($settings_file)) {
                    $writable = drupal_verify_install_file($settings_file, FILE_READABLE | FILE_WRITABLE);
                    $exists = TRUE;
                }
                else {
                    $deleted = @drupal_unlink($settings_file);
                    // We expect deleting the file to be successful (since we just
                    // created it ourselves above), but if it fails somehow, we set a
                    // variable so we can display a one-time error message to the
                    // administrator at the bottom of the requirements list. We also try
                    // to make the file writable, to eliminate any conflicting error
                    // messages in the requirements list.
                    $exists = !$deleted;
                    if ($exists) {
                        $settings_file_ownership_error = TRUE;
                        $writable = drupal_verify_install_file($settings_file, FILE_READABLE | FILE_WRITABLE);
                    }
                }
            }
        }
        // If settings.php does not exist, throw an error.
        if (!$exists) {
            $requirements['settings file exists'] = array(
                'title' => st('Settings file'),
                'value' => st('The settings file does not exist.'),
                'severity' => REQUIREMENT_ERROR,
                'description' => st('The @drupal installer requires that you create a settings file as part of the installation process. Copy the %default_file file to %file. More details about installing Drupal are available in <a href="@install_txt">INSTALL.txt</a>.', array(
                    '@drupal' => drupal_install_profile_distribution_name(),
                    '%file' => $file,
                    '%default_file' => $default_settings_file,
                    '@install_txt' => base_path() . 'INSTALL.txt',
                )),
            );
        }
        else {
            $requirements['settings file exists'] = array(
                'title' => st('Settings file'),
                'value' => st('The %file file exists.', array(
                    '%file' => $file,
                )),
            );
            // If settings.php is not writable, throw an error.
            if (!$writable) {
                $requirements['settings file writable'] = array(
                    'title' => st('Settings file'),
                    'value' => st('The settings file is not writable.'),
                    'severity' => REQUIREMENT_ERROR,
                    'description' => st('The @drupal installer requires write permissions to %file during the installation process. If you are unsure how to grant file permissions, consult the <a href="@handbook_url">online handbook</a>.', array(
                        '@drupal' => drupal_install_profile_distribution_name(),
                        '%file' => $file,
                        '@handbook_url' => 'http://drupal.org/server-permissions',
                    )),
                );
            }
            else {
                $requirements['settings file'] = array(
                    'title' => st('Settings file'),
                    'value' => st('The settings file is writable.'),
                );
            }
            if (!empty($settings_file_ownership_error)) {
                $requirements['settings file ownership'] = array(
                    'title' => st('Settings file'),
                    'value' => st('The settings file is owned by the web server.'),
                    'severity' => REQUIREMENT_ERROR,
                    'description' => st('The @drupal installer failed to create a settings file with proper file ownership. Log on to your web server, remove the existing %file file, and create a new one by copying the %default_file file to %file. More details about installing Drupal are available in <a href="@install_txt">INSTALL.txt</a>. If you have problems with the file permissions on your server, consult the <a href="@handbook_url">online handbook</a>.', array(
                        '@drupal' => drupal_install_profile_distribution_name(),
                        '%file' => $file,
                        '%default_file' => $default_settings_file,
                        '@install_txt' => base_path() . 'INSTALL.txt',
                        '@handbook_url' => 'http://drupal.org/server-permissions',
                    )),
                );
            }
        }
    }
    return $requirements;
}

/**
 * Form constructor for a site configuration form.
 *
 * @param $install_state
 *   An array of information about the current installation state.
 *
 * @see install_configure_form()
 * @see install_configure_form_validate()
 * @see install_configure_form_submit()
 * @ingroup forms
 */
function _install_configure_form($form, &$form_state, &$install_state) {
    include_once DRUPAL_ROOT . '/includes/locale.inc';
    $form['site_information'] = array(
        '#type' => 'fieldset',
        '#title' => st('Site information'),
        '#collapsible' => FALSE,
    );
    $form['site_information']['site_name'] = array(
        '#type' => 'textfield',
        '#title' => st('Site name'),
        '#required' => TRUE,
        '#weight' => -20,
    );
    $form['site_information']['site_mail'] = array(
        '#type' => 'textfield',
        '#title' => st('Site e-mail address'),
        '#default_value' => ini_get('sendmail_from'),
        '#description' => st("Automated e-mails, such as registration information, will be sent from this address. Use an address ending in your site's domain to help prevent these e-mails from being flagged as spam."),
        '#required' => TRUE,
        '#weight' => -15,
    );
    $form['admin_account'] = array(
        '#type' => 'fieldset',
        '#title' => st('Site maintenance account'),
        '#collapsible' => FALSE,
    );
    $form['admin_account']['account']['#tree'] = TRUE;
    $form['admin_account']['account']['name'] = array(
        '#type' => 'textfield',
        '#title' => st('Username'),
        '#maxlength' => USERNAME_MAX_LENGTH,
        '#description' => st('Spaces are allowed; punctuation is not allowed except for periods, hyphens, and underscores.'),
        '#required' => TRUE,
        '#weight' => -10,
        '#attributes' => array(
            'class' => array(
                'username',
            ),
        ),
    );
    $form['admin_account']['account']['mail'] = array(
        '#type' => 'textfield',
        '#title' => st('E-mail address'),
        '#maxlength' => EMAIL_MAX_LENGTH,
        '#required' => TRUE,
        '#weight' => -5,
    );
    $form['admin_account']['account']['pass'] = array(
        '#type' => 'password_confirm',
        '#required' => TRUE,
        '#size' => 25,
        '#weight' => 0,
    );
    $form['server_settings'] = array(
        '#type' => 'fieldset',
        '#title' => st('Server settings'),
        '#collapsible' => FALSE,
    );
    $countries = country_get_list();
    $form['server_settings']['site_default_country'] = array(
        '#type' => 'select',
        '#title' => st('Default country'),
        '#empty_value' => '',
        '#default_value' => variable_get('site_default_country', NULL),
        '#options' => $countries,
        '#description' => st('Select the default country for the site.'),
        '#weight' => 0,
    );
    $form['server_settings']['date_default_timezone'] = array(
        '#type' => 'select',
        '#title' => st('Default time zone'),
        '#default_value' => date_default_timezone_get(),
        '#options' => system_time_zones(),
        '#description' => st('By default, dates in this site will be displayed in the chosen time zone.'),
        '#weight' => 5,
        '#attributes' => array(
            'class' => array(
                'timezone-detect',
            ),
        ),
    );
    $form['server_settings']['clean_url'] = array(
        '#type' => 'hidden',
        '#default_value' => 0,
        '#attributes' => array(
            'id' => 'edit-clean-url',
            'class' => array(
                'install',
            ),
        ),
    );
    $form['update_notifications'] = array(
        '#type' => 'fieldset',
        '#title' => st('Update notifications'),
        '#collapsible' => FALSE,
    );
    $form['update_notifications']['update_status_module'] = array(
        '#type' => 'checkboxes',
        '#options' => array(
            1 => st('Check for updates automatically'),
            2 => st('Receive e-mail notifications'),
        ),
        '#default_value' => array(
            1,
            2,
        ),
        '#description' => st('The system will notify you when updates and important security releases are available for installed components. Anonymous information about your site is sent to <a href="@drupal">Drupal.org</a>.', array(
            '@drupal' => 'http://drupal.org',
        )),
        '#weight' => 15,
    );
    $form['actions'] = array(
        '#type' => 'actions',
    );
    $form['actions']['submit'] = array(
        '#type' => 'submit',
        '#value' => st('Save and continue'),
        '#weight' => 15,
    );
    return $form;
}

/**
 * Form validation handler for install_configure_form().
 *
 * @see install_configure_form_submit()
 */
function install_configure_form_validate($form, &$form_state) {
    if ($error = user_validate_name($form_state['values']['account']['name'])) {
        form_error($form['admin_account']['account']['name'], $error);
    }
    if ($error = user_validate_mail($form_state['values']['account']['mail'])) {
        form_error($form['admin_account']['account']['mail'], $error);
    }
    if ($error = user_validate_mail($form_state['values']['site_mail'])) {
        form_error($form['site_information']['site_mail'], $error);
    }
}

/**
 * Form submission handler for install_configure_form().
 *
 * @see install_configure_form_validate()
 */
function install_configure_form_submit($form, &$form_state) {
    global $user;
    variable_set('site_name', $form_state['values']['site_name']);
    variable_set('site_mail', $form_state['values']['site_mail']);
    variable_set('date_default_timezone', $form_state['values']['date_default_timezone']);
    variable_set('site_default_country', $form_state['values']['site_default_country']);
    // Enable update.module if this option was selected.
    if ($form_state['values']['update_status_module'][1]) {
        module_enable(array(
            'update',
        ), FALSE);
        // Add the site maintenance account's email address to the list of
        // addresses to be notified when updates are available, if selected.
        if ($form_state['values']['update_status_module'][2]) {
            variable_set('update_notify_emails', array(
                $form_state['values']['account']['mail'],
            ));
        }
    }
    // We precreated user 1 with placeholder values. Let's save the real values.
    $account = user_load(1);
    $merge_data = array(
        'init' => $form_state['values']['account']['mail'],
        'roles' => !empty($account->roles) ? $account->roles : array(),
        'status' => 1,
        'timezone' => $form_state['values']['date_default_timezone'],
    );
    user_save($account, array_merge($form_state['values']['account'], $merge_data));
    // Load global $user and perform final login tasks.
    $user = user_load(1);
    user_login_finalize();
    if (isset($form_state['values']['clean_url'])) {
        variable_set('clean_url', $form_state['values']['clean_url']);
    }
    // Record when this install ran.
    variable_set('install_time', $_SERVER['REQUEST_TIME']);
}