/com_contenthistory/models/history.php

<?php
/**
 * @package     Joomla.Administrator
 * @subpackage  com_contenthistory
 *
 * @copyright   Copyright (C) 2005 - 2015 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

defined('_JEXEC') or die;

/**
 * Methods supporting a list of contenthistory records.
 *
 * @since  3.2
 */
class ContenthistoryModelHistory extends JModelList
{
    /**
     * Constructor.
     *
     * @param   array  $config  An optional associative array of configuration settings.
     *
     * @see     JControllerLegacy
     * @since   3.2
     */
    public function __construct($config = array())
    {
        if (empty($config['filter_fields']))
        {
            $config['filter_fields'] = array(
                    'version_id', 'h.version_id',
                    'version_note', 'h.version_note',
                    'save_date', 'h.save_date',
                    'editor_user_id', 'h.editor_user_id',
            );
        }

        parent::__construct($config);
    }

    /**
     * Method to test whether a history record can be deleted. Note that we check whether we have edit permissions
     * for the content item row.
     *
     * @param   object  $record  A JTable object.
     *
     * @return  boolean  True if allowed to delete the record. Defaults to the permission set in the component.
     *
     * @since   3.2
     */
    protected function canEdit($record)
    {
        if (!empty($record->ucm_type_id))
        {
            $result = false;

            // Check that the type id matches the type alias
            $typeAlias = JFactory::getApplication()->input->get('type_alias');
            $contentTypeTable = JTable::getInstance('Contenttype', 'JTable');

            if ($contentTypeTable->getTypeId($typeAlias) == $record->ucm_type_id)
            {
                /**
                 * Make sure user has edit privileges for this content item. Note that we use edit permissions
                 * for the content item, not delete permissions for the content history row.
                 */
                $user = JFactory::getUser();
                $result = $user->authorise('core.edit', $typeAlias . (int) $record->version_id);
            }
        }

        return $result;
    }

    /**
     * Method to delete one or more records from content history table.
     *
     * @param   array  &$pks  An array of record primary keys.
     *
     * @return  boolean  True if successful, false if an error occurs.
     *
     * @since   3.2
     */
    public function delete(&$pks)
    {
        $pks = (array) $pks;
        $table = $this->getTable();

        // Iterate the items to delete each one.
        foreach ($pks as $i => $pk)
        {
            if ($table->load($pk))
            {
                if ($this->canEdit($table))
                {
                    if (!$table->delete($pk))
                    {
                        $this->setError($table->getError());

                        return false;
                    }
                }
                else
                {
                    // Prune items that you can't change.
                    unset($pks[$i]);
                    $error = $this->getError();

                    if ($error)
                    {
                        JLog::add($error, JLog::WARNING, 'jerror');

                        return false;
                    }
                    else
                    {
                        JLog::add(JText::_('JLIB_APPLICATION_ERROR_DELETE_NOT_PERMITTED'), JLog::WARNING, 'jerror');

                        return false;
                    }
                }
            }
            else
            {
                $this->setError($table->getError());

                return false;
            }
        }

        // Clear the component's cache
        $this->cleanCache();

        return true;
    }

    /**
     * Method to get a table object, load it if necessary.
     *
     * @param   string  $type    The table name. Optional.
     * @param   string  $prefix  The class prefix. Optional.
     * @param   array   $config  Configuration array for model. Optional.
     *
     * @return  JTable  A JTable object
     *
     * @since   3.2
     */
    public function getTable($type = 'Contenthistory', $prefix = 'JTable', $config = array())
    {
        return JTable::getInstance($type, $prefix, $config);
    }

    /**
     * Method to toggle on and off the keep forever value for one or more records from content history table.
     *
     * @param   array  &$pks  An array of record primary keys.
     *
     * @return  boolean  True if successful, false if an error occurs.
     *
     * @since   3.2
     */
    public function keep(&$pks)
    {
        $pks = (array) $pks;
        $table = $this->getTable();

        // Iterate the items to delete each one.
        foreach ($pks as $i => $pk)
        {
            if ($table->load($pk))
            {
                if ($this->canEdit($table))
                {
                    $table->keep_forever = $table->keep_forever ? 0 : 1;

                    if (!$table->store())
                    {
                        $this->setError($table->getError());

                        return false;
                    }
                }
                else
                {
                    // Prune items that you can't change.
                    unset($pks[$i]);
                    $error = $this->getError();

                    if ($error)
                    {
                        JLog::add($error, JLog::WARNING, 'jerror');

                        return false;
                    }
                    else
                    {
                        JLog::add(JText::_('COM_CONTENTHISTORY_ERROR_KEEP_NOT_PERMITTED'), JLog::WARNING, 'jerror');

                        return false;
                    }
                }
            }
            else
            {
                $this->setError($table->getError());

                return false;
            }
        }

        // Clear the component's cache
        $this->cleanCache();

        return true;
    }

    /**
     * Method to auto-populate the model state.
     *
     * Note. Calling getState in this method will result in recursion.
     *
     * @param   string  $ordering   An optional ordering field.
     * @param   string  $direction  An optional direction (asc|desc).
     *
     * @return  void
     *
     * @since   3.2
     */
    protected function populateState($ordering = null, $direction = null)
    {
        $input = JFactory::getApplication()->input;
        $itemId = $input->get('item_id', 0, 'integer');
        $typeId = $input->get('type_id', 0, 'integer');
        $typeAlias = $input->get('type_alias', '', 'string');

        $this->setState('item_id', $itemId);
        $this->setState('type_id', $typeId);
        $this->setState('type_alias', $typeAlias);
        $this->setState('sha1_hash', $this->getSha1Hash());

        // Load the parameters.
        $params = JComponentHelper::getParams('com_contenthistory');
        $this->setState('params', $params);

        // List state information.
        parent::populateState('h.save_date', 'DESC');
    }

    /**
     * Build an SQL query to load the list data.
     *
     * @return  JDatabaseQuery
     *
     * @since   3.2
     */
    protected function getListQuery()
    {
        // Create a new query object.
        $db = $this->getDbo();
        $query = $db->getQuery(true);

        // Select the required fields from the table.
        $query->select(
            $this->getState(
                'list.select',
                'h.version_id, h.ucm_item_id, h.ucm_type_id, h.version_note, h.save_date, h.editor_user_id,' .
                'h.character_count, h.sha1_hash, h.version_data, h.keep_forever'
            )
        )
        ->from($db->quoteName('#__ucm_history') . ' AS h')
        ->where($db->quoteName('h.ucm_item_id') . ' = ' . $this->getState('item_id'))
        ->where($db->quoteName('h.ucm_type_id') . ' = ' . $this->getState('type_id'))

        // Join over the users for the editor
        ->select('uc.name AS editor')
        ->join('LEFT', '#__users AS uc ON uc.id = h.editor_user_id');

        // Add the list ordering clause.
        $orderCol = $this->state->get('list.ordering');
        $orderDirn = $this->state->get('list.direction');
        $query->order($db->quoteName($orderCol) . $orderDirn);

        return $query;
    }

    /**
     * Get the sha1 hash value for the current item being edited.
     *
     * @return  string  sha1 hash of row data
     *
     * @since   3.2
     */
    protected function getSha1Hash()
    {
        $result = false;
        $typeTable = JTable::getInstance('Contenttype', 'JTable');
        $typeId = JFactory::getApplication()->input->getInteger('type_id', 0);
        $typeTable->load($typeId);
        $typeAliasArray = explode('.', $typeTable->type_alias);
        JTable::addIncludePath(JPATH_ROOT . '/administrator/components/' . $typeAliasArray[0] . '/tables');
        $contentTable = $typeTable->getContentTable();
        $keyValue = JFactory::getApplication()->input->getInteger('item_id', 0);

        if ($contentTable && $contentTable->load($keyValue))
        {
            $helper = new JHelper;

            $dataObject = $helper->getDataObject($contentTable);
            $result = $this->getTable('Contenthistory', 'JTable')->getSha1(json_encode($dataObject), $typeTable);
        }

        return $result;
    }
}