class views_handler

class views_handler extends views_object {
    
    /**
     * The top object of a view.
     *
     * @var view
     */
    var $view = NULL;
    
    /**
     * Where the $query object will reside:
     *
     * @var views_plugin_query
     */
    var $query = NULL;
    
    /**
     * The type of the handler, for example filter/footer/field.
     */
    var $handler_type = NULL;
    
    /**
     * init the handler with necessary data.
     * @param $view
     *   The $view object this handler is attached to.
     * @param $options
     *   The item from the database; the actual contents of this will vary
     *   based upon the type of handler.
     */
    function init(&$view, $options) {
        $this->view =& $view;
        $display_id = $this->view->current_display;
        // Check to see if this handler type is defaulted. Note that
        // we have to do a lookup because the type is singular but the
        // option is stored as the plural.
        $types = views_object_types();
        $plural = $this->handler_type;
        if (isset($types[$this->handler_type]['plural'])) {
            $plural = $types[$this->handler_type]['plural'];
        }
        if ($this->view->display_handler
            ->is_defaulted($plural)) {
            $display_id = 'default';
        }
        $this->localization_keys = array(
            $display_id,
            $this->handler_type,
            $options['table'],
            $options['id'],
        );
        $this->unpack_options($this->options, $options);
        // This exist on most handlers, but not all. So they are still optional.
        if (isset($options['table'])) {
            $this->table = $options['table'];
        }
        if (isset($this->definition['real field'])) {
            $this->real_field = $this->definition['real field'];
        }
        if (isset($this->definition['field'])) {
            $this->real_field = $this->definition['field'];
        }
        if (isset($options['field'])) {
            $this->field = $options['field'];
            if (!isset($this->real_field)) {
                $this->real_field = $options['field'];
            }
        }
        $this->query =& $view->query;
    }
    function option_definition() {
        $options = parent::option_definition();
        $options['id'] = array(
            'default' => '',
        );
        $options['table'] = array(
            'default' => '',
        );
        $options['field'] = array(
            'default' => '',
        );
        $options['relationship'] = array(
            'default' => 'none',
        );
        $options['group_type'] = array(
            'default' => 'group',
        );
        $options['ui_name'] = array(
            'default' => '',
        );
        return $options;
    }
    
    /**
     * Return a string representing this handler's name in the UI.
     */
    function ui_name($short = FALSE) {
        if (!empty($this->options['ui_name'])) {
            $title = check_plain($this->options['ui_name']);
            return $title;
        }
        $title = $short && isset($this->definition['title short']) ? $this->definition['title short'] : $this->definition['title'];
        return t('!group: !title', array(
            '!group' => $this->definition['group'],
            '!title' => $title,
        ));
    }
    
    /**
     * Shortcut to get a handler's raw field value.
     *
     * This should be overridden for handlers with formulae or other
     * non-standard fields. Because this takes an argument, fields
     * overriding this can just call return parent::get_field($formula)
     */
    function get_field($field = NULL) {
        if (!isset($field)) {
            if (!empty($this->formula)) {
                $field = $this->get_formula();
            }
            else {
                $field = $this->table_alias . '.' . $this->real_field;
            }
        }
        // If grouping, check to see if the aggregation method needs to modify the field.
        if ($this->view->display_handler
            ->use_group_by()) {
            $info = $this->query
                ->get_aggregation_info();
            if (!empty($info[$this->options['group_type']]['method']) && function_exists($info[$this->options['group_type']]['method'])) {
                return $info[$this->options['group_type']]['method']($this->options['group_type'], $field);
            }
        }
        return $field;
    }
    
    /**
     * Sanitize the value for output.
     *
     * @param $value
     *   The value being rendered.
     * @param $type
     *   The type of sanitization needed. If not provided, check_plain() is used.
     */
    function sanitize_value($value, $type = NULL) {
        switch ($type) {
            case 'xss':
                $value = filter_xss($value);
                break;
            case 'url':
                $value = check_url($value);
                break;
            default:
                $value = check_plain($value);
                break;
        }
        return $value;
    }
    
    /**
     * Validate the options form.
     */
    function options_validate($form, &$form_state) {
    }
    function options_form(&$form, &$form_state) {
        $form['ui_name'] = array(
            '#type' => 'textfield',
            '#title' => t('Administrative Title'),
            '#description' => t('This title will be displayed on the views edit page instead of the default one. This might be useful if you have the same item twice.'),
            '#default_value' => $this->options['ui_name'],
        );
    }
    
    /**
     * Perform any necessary changes to the form values prior to storage.
     * There is no need for this function to actually store the data.
     */
    function options_submit($form, &$form_state) {
    }
    
    /**
     * Provides the handler some groupby.
     */
    function use_group_by() {
        return TRUE;
    }
    
    /**
     * If a handler has 'extra options' it will get a little settings widget and
     * another form called extra_options.
     */
    function has_extra_options() {
        return FALSE;
    }
    
    /**
     * Provide defaults for the handler.
     */
    function extra_options(&$option) {
    }
    
    /**
     * Provide a form for setting options.
     */
    function extra_options_form(&$form, &$form_state) {
    }
    
    /**
     * Validate the options form.
     */
    function extra_options_validate($form, &$form_state) {
    }
    
    /**
     * Perform any necessary changes to the form values prior to storage.
     * There is no need for this function to actually store the data.
     */
    function extra_options_submit($form, &$form_state) {
    }
    
    /**
     * Determine if a handler can be exposed.
     */
    function can_expose() {
        return FALSE;
    }
    
    /**
     * Set new exposed option defaults when exposed setting is flipped
     * on.
     */
    function expose_options() {
    }
    
    /**
     * Get information about the exposed form for the form renderer.
     */
    function exposed_info() {
    }
    
    /**
     * Render our chunk of the exposed handler form when selecting
     */
    function exposed_form(&$form, &$form_state) {
    }
    
    /**
     * Validate the exposed handler form
     */
    function exposed_validate(&$form, &$form_state) {
    }
    
    /**
     * Submit the exposed handler form
     */
    function exposed_submit(&$form, &$form_state) {
    }
    
    /**
     * Overridable form for exposed handler options.
     *
     * If overridden, it is best to call the parent or re-implement
     * the stuff here.
     *
     * Many handlers will need to override this in order to provide options
     * that are nicely tailored to the given filter.
     */
    function expose_form(&$form, &$form_state) {
        $form['expose']['start_left'] = array(
            '#value' => '<div class="views-left-50">',
        );
        $this->expose_form_left($form, $form_state);
        $form['expose']['end_left'] = array(
            '#value' => '</div>',
        );
        $form['expose']['start_checkboxes'] = array(
            '#value' => '<div class="form-checkboxes views-left-40 clear-block">',
        );
        $this->expose_form_right($form, $form_state);
        $form['expose']['end_checkboxes'] = array(
            '#value' => '</div>',
        );
    }
    function expose_form_left(&$form, &$form_state) {
    }
    function expose_form_right(&$form, &$form_state) {
    }
    
    /**
     * Validate the options form.
     */
    function expose_validate($form, &$form_state) {
    }
    
    /**
     * Perform any necessary changes to the form exposes prior to storage.
     * There is no need for this function to actually store the data.
     */
    function expose_submit($form, &$form_state) {
    }
    
    /**
     * Shortcut to display the expose/hide button.
     */
    function show_expose_button(&$form, &$form_state) {
        $form['expose_button'] = array(
            '#prefix' => '<div class="views-expose clear-block">',
            '#suffix' => '</div>',
        );
        if (empty($this->options['exposed'])) {
            $form['expose_button']['button'] = array(
                '#type' => 'submit',
                '#value' => t('Expose'),
                '#submit' => array(
                    'views_ui_config_item_form_expose',
                ),
            );
            $form['expose_button']['markup'] = array(
                '#prefix' => '<div class="description">',
                '#value' => t('This item is currently not exposed. If you <strong>expose</strong> it, users will be able to change the filter as they view it.'),
                '#suffix' => '</div>',
            );
        }
        else {
            $form['expose_button']['button'] = array(
                '#type' => 'submit',
                '#value' => t('Hide'),
                '#submit' => array(
                    'views_ui_config_item_form_expose',
                ),
            );
            $form['expose_button']['markup'] = array(
                '#prefix' => '<div class="description">',
                '#value' => t('This item is currently exposed. If you <strong>hide</strong> it, users will not be able to change the filter as they view it.'),
                '#suffix' => '</div>',
            );
        }
    }
    
    /**
     * Shortcut to display the exposed options form.
     */
    function show_expose_form(&$form, &$form_state) {
        if (empty($this->options['exposed'])) {
            return;
        }
        $form['expose'] = array(
            '#prefix' => '<div class="views-expose-options clear-block">',
            '#suffix' => '</div>',
        );
        $this->expose_form($form, $form_state);
        // When we click the expose button, we add new gadgets to the form but they
        // have no data in $_POST so their defaults get wiped out. This prevents
        // these defaults from getting wiped out. This setting will only be TRUE
        // during a 2nd pass rerender.
        if (!empty($form_state['force_expose_options'])) {
            foreach (element_children($form['expose']) as $id) {
                if (isset($form['expose'][$id]['#default_value']) && !isset($form['expose'][$id]['#value'])) {
                    $form['expose'][$id]['#value'] = $form['expose'][$id]['#default_value'];
                }
            }
        }
    }
    
    /**
     * Check whether current user has access to this handler.
     *
     * @return boolean
     */
    function access() {
        if (isset($this->definition['access callback']) && function_exists($this->definition['access callback'])) {
            if (isset($this->definition['access arguments']) && is_array($this->definition['access arguments'])) {
                return call_user_func_array($this->definition['access callback'], $this->definition['access arguments']);
            }
            return $this->definition['access callback']();
        }
        return TRUE;
    }
    
    /**
     * Run before the view is built.
     *
     * This gives all the handlers some time to set up before any handler has
     * been fully run.
     */
    function pre_query() {
    }
    
    /**
     * Called just prior to query(), this lets a handler set up any relationship
     * it needs.
     */
    function set_relationship() {
        // Ensure this gets set to something.
        $this->relationship = NULL;
        // Don't process non-existant relationships.
        if (empty($this->options['relationship']) || $this->options['relationship'] == 'none') {
            return;
        }
        $relationship = $this->options['relationship'];
        // Ignore missing/broken relationships.
        if (empty($this->view->relationship[$relationship])) {
            return;
        }
        // Check to see if the relationship has already processed. If not, then we
        // cannot process it.
        if (empty($this->view->relationship[$relationship]->alias)) {
            return;
        }
        // Finally!
        $this->relationship = $this->view->relationship[$relationship]->alias;
    }
    
    /**
     * Add this handler into the query.
     *
     * If we were using PHP5, this would be abstract.
     */
    function query($group_by = FALSE) {
    }
    
    /**
     * Ensure the main table for this handler is in the query. This is used
     * a lot.
     */
    function ensure_my_table() {
        if (!isset($this->table_alias)) {
            if (!method_exists($this->query, 'ensure_table')) {
                vpr(t('Ensure my table called but query has no ensure_table method.'));
                return;
            }
            $this->table_alias = $this->query
                ->ensure_table($this->table, $this->relationship);
        }
        return $this->table_alias;
    }
    
    /**
     * Provide text for the administrative summary
     */
    function admin_summary() {
    }
    
    /**
     * Determine if the argument needs a style plugin.
     *
     * @return TRUE/FALSE
     */
    function needs_style_plugin() {
        return FALSE;
    }
    
    /**
     * Determine if this item is 'exposed', meaning it provides form elements
     * to let users modify the view.
     *
     * @return TRUE/FALSE
     */
    function is_exposed() {
        return !empty($this->options['exposed']);
    }
    
    /**
     * Take input from exposed handlers and assign to this handler, if necessary.
     */
    function accept_exposed_input($input) {
        return TRUE;
    }
    
    /**
     * If set to remember exposed input in the session, store it there.
     */
    function store_exposed_input($input, $status) {
        return TRUE;
    }
    
    /**
     * Get the join object that should be used for this handler.
     *
     * This method isn't used a great deal, but it's very handy for easily
     * getting the join if it is necessary to make some changes to it, such
     * as adding an 'extra'.
     */
    function get_join() {
        // get the join from this table that links back to the base table.
        // Determine the primary table to seek
        if (empty($this->query->relationships[$this->relationship])) {
            $base_table = $this->query->base_table;
        }
        else {
            $base_table = $this->query->relationships[$this->relationship]['base'];
        }
        $join = views_get_table_join($this->table, $base_table);
        if ($join) {
            return drupal_clone($join);
        }
    }
    
    /**
     * Validates the handler against the complete View.
     *
     * This is called when the complete View is being validated. For validating
     * the handler options form use options_validate().
     *
     * @see views_handler::options_validate()
     *
     * @return
     *   Empty array if the handler is valid; an array of error strings if it is not.
     */
    function validate() {
        return array();
    }
    
    /**
     * Determine if the handler is considered 'broken', meaning it's a
     * a placeholder used when a handler can't be found.
     */
    function broken() {
    }

}