Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Library functions for managing text filter plugins.

 *

 * @package   core

 * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

/** The states a filter can be in, stored in the filter_active table. */

define('TEXTFILTER_ON', 1);

/** The states a filter can be in, stored in the filter_active table. */

define('TEXTFILTER_INHERIT', 0);

/** The states a filter can be in, stored in the filter_active table. */

define('TEXTFILTER_OFF', -1);

/** The states a filter can be in, stored in the filter_active table. */

define('TEXTFILTER_DISABLED', -9999);

/**

 * Define one exclusive separator that we'll use in the temp saved tags

 *  keys. It must be something rare enough to avoid having matches with

 *  filterobjects. MDL-18165

 */

define('TEXTFILTER_EXCL_SEPARATOR', chr(0x1F) . '%' . chr(0x1F));

/**

 * Look up the name of this filter

 *

 * @param string $filter the filter name

 * @return string the human-readable name for this filter.

 */

function filter_get_name($filter) {

    if (strpos($filter, 'filter/') === 0) {

        debugging("Old '$filter'' parameter used in filter_get_name()");

        $filter = substr($filter, 7);

    } else if (strpos($filter, '/') !== false) {

        throw new coding_exception('Unknown filter type ' . $filter);

    }

    if (get_string_manager()->string_exists('filtername', 'filter_' . $filter)) {

        return get_string('filtername', 'filter_' . $filter);

    } else {

        return $filter;

    }

}

/**

 * Get the names of all the filters installed in this Moodle.

 *

 * @return array path => filter name from the appropriate lang file. e.g.

 * array('tex' => 'TeX Notation');

 * sorted in alphabetical order of name.

 */

function filter_get_all_installed() {

    $filternames = array();

    foreach (core_component::get_plugin_list('filter') as $filter => $fulldir) {

        if (class_exists("\\filter_{$filter}\\text_filter") || is_readable("$fulldir/filter.php")) {

            $filternames[$filter] = filter_get_name($filter);

        }

    }

    core_collator::asort($filternames);

    return $filternames;

}

/**

 * Set the global activated state for a text filter.

 *

 * @param string $filtername The filter name, for example 'tex'.

 * @param int $state One of the values TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_DISABLED.

 * @param int $move -1 means up, 0 means the same, 1 means down

 */

function filter_set_global_state($filtername, $state, $move = 0) {

    global $DB;

    // Check requested state is valid.

    if (!in_array($state, array(TEXTFILTER_ON, TEXTFILTER_OFF, TEXTFILTER_DISABLED))) {

        throw new coding_exception("Illegal option '$state' passed to filter_set_global_state. " .

                "Must be one of TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_DISABLED.");

    }

    if ($move > 0) {

        $move = 1;

    } else if ($move < 0) {

        $move = -1;

    }

    if (strpos($filtername, 'filter/') === 0) {

        $filtername = substr($filtername, 7);

    } else if (strpos($filtername, '/') !== false) {

        throw new coding_exception("Invalid filter name '$filtername' used in filter_set_global_state()");

    }

    $transaction = $DB->start_delegated_transaction();

    $syscontext = context_system::instance();

    $filters = $DB->get_records('filter_active', array('contextid' => $syscontext->id), 'sortorder ASC');

    $on = array();

    $off = array();

    foreach ($filters as $f) {

        if ($f->active == TEXTFILTER_DISABLED) {

            $off[$f->filter] = $f;

        } else {

            $on[$f->filter] = $f;

        }

    }

    // Update the state or add new record.

    if (isset($on[$filtername])) {

        $filter = $on[$filtername];

        if ($filter->active != $state) {

            add_to_config_log('filter_active', $filter->active, $state, $filtername);

            $filter->active = $state;

            $DB->update_record('filter_active', $filter);

            if ($filter->active == TEXTFILTER_DISABLED) {

                unset($on[$filtername]);

                $off = array($filter->filter => $filter) + $off;

            }

        }

    } else if (isset($off[$filtername])) {

        $filter = $off[$filtername];

        if ($filter->active != $state) {

            add_to_config_log('filter_active', $filter->active, $state, $filtername);

            $filter->active = $state;

            $DB->update_record('filter_active', $filter);

            if ($filter->active != TEXTFILTER_DISABLED) {

                unset($off[$filtername]);

                $on[$filter->filter] = $filter;

            }

        }

    } else {

        add_to_config_log('filter_active', '', $state, $filtername);

        $filter = new stdClass();

        $filter->filter    = $filtername;

        $filter->contextid = $syscontext->id;

        $filter->active    = $state;

        $filter->sortorder = 99999;

        $filter->id = $DB->insert_record('filter_active', $filter);

        $filters[$filter->id] = $filter;

        if ($state == TEXTFILTER_DISABLED) {

            $off[$filter->filter] = $filter;

        } else {

            $on[$filter->filter] = $filter;

        }

    }

    // Move only active.

    if ($move != 0 and isset($on[$filter->filter])) {

        // Capture the old order for logging.

        $oldorder = implode(', ', array_map(

                function($f) {

                    return $f->filter;

                }, $on));

        // Work out the new order.

        $i = 1;

        foreach ($on as $f) {

            $f->newsortorder = $i;

            $i++;

        }

        $filter->newsortorder = $filter->newsortorder + $move;

        foreach ($on as $f) {

            if ($f->id == $filter->id) {

                continue;

            }

            if ($f->newsortorder == $filter->newsortorder) {

                if ($move == 1) {

                    $f->newsortorder = $f->newsortorder - 1;

                } else {

                    $f->newsortorder = $f->newsortorder + 1;

                }

            }

        }

        core_collator::asort_objects_by_property($on, 'newsortorder', core_collator::SORT_NUMERIC);

        // Log in config_log.

        $neworder = implode(', ', array_map(

                function($f) {

                    return $f->filter;

                }, $on));

        add_to_config_log('order', $oldorder, $neworder, 'core_filter');

    }

    // Inactive are sorted by filter name.

    core_collator::asort_objects_by_property($off, 'filter', core_collator::SORT_NATURAL);

    // Update records if necessary.

    $i = 1;

    foreach ($on as $f) {

        if ($f->sortorder != $i) {

            $DB->set_field('filter_active', 'sortorder', $i, array('id' => $f->id));

        }

        $i++;

    }

    foreach ($off as $f) {

        if ($f->sortorder != $i) {

            $DB->set_field('filter_active', 'sortorder', $i, array('id' => $f->id));

        }

        $i++;

    }

    $transaction->allow_commit();

}

/**

 * Returns the active state for a filter in the given context.

 *

 * @param string $filtername The filter name, for example 'tex'.

 * @param integer $contextid The id of the context to get the data for.

 * @return int value of active field for the given filter.

 */

function filter_get_active_state(string $filtername, $contextid = null): int {

    global $DB;

    if ($contextid === null) {

        $contextid = context_system::instance()->id;

    }

    if (is_object($contextid)) {

        $contextid = $contextid->id;

    }

    if (strpos($filtername, 'filter/') === 0) {

        $filtername = substr($filtername, 7);

    } else if (strpos($filtername, '/') !== false) {

        throw new coding_exception("Invalid filter name '$filtername' used in filter_is_enabled()");

    }

    if ($active = $DB->get_field('filter_active', 'active', array('filter' => $filtername, 'contextid' => $contextid))) {

        return $active;

    }

    return TEXTFILTER_DISABLED;

}

/**

 * @param string $filtername The filter name, for example 'tex'.

 * @return boolean is this filter allowed to be used on this site. That is, the

 *      admin has set the global 'active' setting to On, or Off, but available.

 */

function filter_is_enabled($filtername) {

    if (strpos($filtername, 'filter/') === 0) {

        $filtername = substr($filtername, 7);

    } else if (strpos($filtername, '/') !== false) {

        throw new coding_exception("Invalid filter name '$filtername' used in filter_is_enabled()");

    }

    return array_key_exists($filtername, filter_get_globally_enabled());

}

/**

 * Return a list of all the filters that may be in use somewhere.

 *

 * @return array where the keys and values are both the filter name, like 'tex'.

 */

function filter_get_globally_enabled() {

    $cache = \cache::make_from_params(\cache_store::MODE_REQUEST, 'core_filter', 'global_filters');

    $enabledfilters = $cache->get('enabled');

    if ($enabledfilters !== false) {

        return $enabledfilters;

    }

    $filters = filter_get_global_states();

    $enabledfilters = array();

    foreach ($filters as $filter => $filerinfo) {

        if ($filerinfo->active != TEXTFILTER_DISABLED) {

            $enabledfilters[$filter] = $filter;

        }

    }

    $cache->set('enabled', $enabledfilters);

    return $enabledfilters;

}

/**

 * Get the globally enabled filters.

 *

 * This returns the filters which could be used in any context. Essentially

 * the filters which are not disabled for the entire site.

 *

 * @return array Keys are filter names, and values the config.

 */

function filter_get_globally_enabled_filters_with_config() {

    global $DB;

    $sql = "SELECT f.filter, fc.name, fc.value

              FROM {filter_active} f

         LEFT JOIN {filter_config} fc

                ON fc.filter = f.filter

               AND fc.contextid = f.contextid

             WHERE f.contextid = :contextid

               AND f.active != :disabled

          ORDER BY f.sortorder";

    $rs = $DB->get_recordset_sql($sql, [

        'contextid' => context_system::instance()->id,

        'disabled' => TEXTFILTER_DISABLED

    ]);

    // Massage the data into the specified format to return.

    $filters = array();

    foreach ($rs as $row) {

        if (!isset($filters[$row->filter])) {

            $filters[$row->filter] = array();

        }

        if ($row->name !== null) {

            $filters[$row->filter][$row->name] = $row->value;

        }

    }

    $rs->close();

    return $filters;

}

/**

 * Return the names of the filters that should also be applied to strings

 * (when they are enabled).

 *

 * @return array where the keys and values are both the filter name, like 'tex'.

 */

function filter_get_string_filters() {

    global $CFG;

    $stringfilters = array();

    if (!empty($CFG->filterall) && !empty($CFG->stringfilters)) {

        $stringfilters = explode(',', $CFG->stringfilters);

        $stringfilters = array_combine($stringfilters, $stringfilters);

    }

    return $stringfilters;

}

/**

 * Sets whether a particular active filter should be applied to all strings by

 * format_string, or just used by format_text.

 *

 * @param string $filter The filter name, for example 'tex'.

 * @param boolean $applytostrings if true, this filter will apply to format_string

 *      and format_text, when it is enabled.

 */

function filter_set_applies_to_strings($filter, $applytostrings) {

    $stringfilters = filter_get_string_filters();

    $prevfilters = $stringfilters;

    $allfilters = core_component::get_plugin_list('filter');

    if ($applytostrings) {

        $stringfilters[$filter] = $filter;

    } else {

        unset($stringfilters[$filter]);

    }

    // Remove missing filters.

    foreach ($stringfilters as $filter) {

        if (!isset($allfilters[$filter])) {

            unset($stringfilters[$filter]);

        }

    }

    if ($prevfilters != $stringfilters) {

        set_config('stringfilters', implode(',', $stringfilters));

        set_config('filterall', !empty($stringfilters));

    }

}

/**

 * Set the local activated state for a text filter.

 *

 * @param string $filter The filter name, for example 'tex'.

 * @param integer $contextid The id of the context to get the local config for.

 * @param integer $state One of the values TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_INHERIT.

 * @return void

 */

function filter_set_local_state($filter, $contextid, $state) {

    global $DB;

    // Check requested state is valid.

    if (!in_array($state, array(TEXTFILTER_ON, TEXTFILTER_OFF, TEXTFILTER_INHERIT))) {

        throw new coding_exception("Illegal option '$state' passed to filter_set_local_state. " .

                "Must be one of TEXTFILTER_ON, TEXTFILTER_OFF or TEXTFILTER_INHERIT.");

    }

    if ($contextid == context_system::instance()->id) {

        throw new coding_exception('You cannot use filter_set_local_state ' .

                'with $contextid equal to the system context id.');

    }

    if ($state == TEXTFILTER_INHERIT) {

        $DB->delete_records('filter_active', array('filter' => $filter, 'contextid' => $contextid));

        return;

    }

    $rec = $DB->get_record('filter_active', array('filter' => $filter, 'contextid' => $contextid));

    $insert = false;

    if (empty($rec)) {

        $insert = true;

        $rec = new stdClass;

        $rec->filter = $filter;

        $rec->contextid = $contextid;

    }

    $rec->active = $state;

    if ($insert) {

        $DB->insert_record('filter_active', $rec);

    } else {

        $DB->update_record('filter_active', $rec);

    }

}

/**

 * Set a particular local config variable for a filter in a context.

 *

 * @param string $filter The filter name, for example 'tex'.

 * @param integer $contextid The id of the context to get the local config for.

 * @param string $name the setting name.

 * @param string $value the corresponding value.

 */

function filter_set_local_config($filter, $contextid, $name, $value) {

    global $DB;

    $rec = $DB->get_record('filter_config', array('filter' => $filter, 'contextid' => $contextid, 'name' => $name));

    $insert = false;

    if (empty($rec)) {

        $insert = true;

        $rec = new stdClass;

        $rec->filter = $filter;

        $rec->contextid = $contextid;

        $rec->name = $name;

    }

    $rec->value = $value;

    if ($insert) {

        $DB->insert_record('filter_config', $rec);

    } else {

        $DB->update_record('filter_config', $rec);

    }

}

/**

 * Remove a particular local config variable for a filter in a context.

 *

 * @param string $filter The filter name, for example 'tex'.

 * @param integer $contextid The id of the context to get the local config for.

 * @param string $name the setting name.

 */

function filter_unset_local_config($filter, $contextid, $name) {

    global $DB;

    $DB->delete_records('filter_config', array('filter' => $filter, 'contextid' => $contextid, 'name' => $name));

}

/**

 * Get local config variables for a filter in a context. Normally (when your

 * filter is running) you don't need to call this, becuase the config is fetched

 * for you automatically. You only need this, for example, when you are getting

 * the config so you can show the user an editing from.

 *

 * @param string $filter The filter name, for example 'tex'.

 * @param integer $contextid The ID of the context to get the local config for.

 * @return array of name => value pairs.

 */

function filter_get_local_config($filter, $contextid) {

    global $DB;

    return $DB->get_records_menu('filter_config', array('filter' => $filter, 'contextid' => $contextid), '', 'name,value');

}

/**

 * This function is for use by backup. Gets all the filter information specific

 * to one context.

 *

 * @param int $contextid

 * @return array Array with two elements. The first element is an array of objects with

 *      fields filter and active. These come from the filter_active table. The

 *      second element is an array of objects with fields filter, name and value

 *      from the filter_config table.

 */

function filter_get_all_local_settings($contextid) {

    global $DB;

    return array(

        $DB->get_records('filter_active', array('contextid' => $contextid), 'filter', 'filter,active'),

        $DB->get_records('filter_config', array('contextid' => $contextid), 'filter,name', 'filter,name,value'),

    );

}

/**

 * Get the list of active filters, in the order that they should be used

 * for a particular context, along with any local configuration variables.

 *

 * @param context $context a context

 * @return array an array where the keys are the filter names, for example

 *      'tex' and the values are any local

 *      configuration for that filter, as an array of name => value pairs

 *      from the filter_config table. In a lot of cases, this will be an

 *      empty array. So, an example return value for this function might be

 *      array(tex' => array())

 */

function filter_get_active_in_context($context) {

    global $DB, $FILTERLIB_PRIVATE;

    if (!isset($FILTERLIB_PRIVATE)) {

        $FILTERLIB_PRIVATE = new stdClass();

    }

    // Use cache (this is a within-request cache only) if available. See

    // function filter_preload_activities.

    if (isset($FILTERLIB_PRIVATE->active) &&

            array_key_exists($context->id, $FILTERLIB_PRIVATE->active)) {

        return $FILTERLIB_PRIVATE->active[$context->id];

    }

    $contextids = str_replace('/', ',', trim($context->path, '/'));

    // Postgres recordset performance is much better with a limit.

    // This should be much larger than anything needed in practice. The code below checks we don't hit this limit.

    $maxpossiblerows = 10000;

    // The key line in the following query is the HAVING clause.

    // If a filter is disabled at system context, then there is a row with active -9999 and depth 1,

    // so the -MIN is always large, and the MAX will be smaller than that and this filter won't be returned.

    // Otherwise, there will be a bunch of +/-1s at various depths,

    // and this clause verifies there is a +1 that deeper than any -1.

    $rows = $DB->get_recordset_sql("

            SELECT active.filter, fc.name, fc.value

              FROM (

                    SELECT fa.filter, MAX(fa.sortorder) AS sortorder

                      FROM {filter_active} fa

                      JOIN {context} ctx ON fa.contextid = ctx.id

                     WHERE ctx.id IN ($contextids)

                  GROUP BY fa.filter

                    HAVING MAX(fa.active * ctx.depth) > -MIN(fa.active * ctx.depth)

                   ) active

         LEFT JOIN {filter_config} fc ON fc.filter = active.filter AND fc.contextid = ?

          ORDER BY active.sortorder

        ", [$context->id], 0, $maxpossiblerows);

    // Massage the data into the specified format to return.

    $filters = [];

    $rowcount = 0;

    foreach ($rows as $row) {

        $rowcount += 1;

        if (!isset($filters[$row->filter])) {

            $filters[$row->filter] = [];

        }

        if (!is_null($row->name)) {

            $filters[$row->filter][$row->name] = $row->value;

        }

    }

    $rows->close();

    if ($rowcount >= $maxpossiblerows) {

        // If this ever did happen, which seems essentially impossible, then it would lead to very subtle and

        // hard to understand bugs, so ensure it leads to an unmissable error.

        throw new coding_exception('Hit the row limit that should never be hit in filter_get_active_in_context.');

    }

    return $filters;

}

/**

 * Preloads the list of active filters for all activities (modules) on the course

 * using two database queries.

 *

 * @param course_modinfo $modinfo Course object from get_fast_modinfo

 */

function filter_preload_activities(course_modinfo $modinfo) {

    global $DB, $FILTERLIB_PRIVATE;

    if (!isset($FILTERLIB_PRIVATE)) {

        $FILTERLIB_PRIVATE = new stdClass();

    }

    // Don't repeat preload.

    if (!isset($FILTERLIB_PRIVATE->preloaded)) {

        $FILTERLIB_PRIVATE->preloaded = array();

    }

    if (!empty($FILTERLIB_PRIVATE->preloaded[$modinfo->get_course_id()])) {

        return;

    }

    $FILTERLIB_PRIVATE->preloaded[$modinfo->get_course_id()] = true;

    // Get contexts for all CMs.

    $cmcontexts = array();

    $cmcontextids = array();

    foreach ($modinfo->get_cms() as $cm) {

        $modulecontext = context_module::instance($cm->id);

        $cmcontextids[] = $modulecontext->id;

        $cmcontexts[] = $modulecontext;

    }

    // Get course context and all other parents.

    $coursecontext = context_course::instance($modinfo->get_course_id());

    $parentcontextids = explode('/', substr($coursecontext->path, 1));

    $allcontextids = array_merge($cmcontextids, $parentcontextids);

    // Get all filter_active rows relating to all these contexts.

    list ($sql, $params) = $DB->get_in_or_equal($allcontextids);

    $filteractives = $DB->get_records_select('filter_active', "contextid $sql", $params, 'sortorder');

    // Get all filter_config only for the cm contexts.

    list ($sql, $params) = $DB->get_in_or_equal($cmcontextids);

    $filterconfigs = $DB->get_records_select('filter_config', "contextid $sql", $params);

    // Note: I was a bit surprised that filter_config only works for the

    // most specific context (i.e. it does not need to be checked for course

    // context if we only care about CMs) however basede on code in

    // filter_get_active_in_context, this does seem to be correct.

    // Build course default active list. Initially this will be an array of

    // filter name => active score (where an active score >0 means it's active).

    $courseactive = array();

    // Also build list of filter_active rows below course level, by contextid.

    $remainingactives = array();

    // Array lists filters that are banned at top level.

    $banned = array();

    // Add any active filters in parent contexts to the array.

    foreach ($filteractives as $row) {

        $depth = array_search($row->contextid, $parentcontextids);

        if ($depth !== false) {

            // Find entry.

            if (!array_key_exists($row->filter, $courseactive)) {

                $courseactive[$row->filter] = 0;

            }

            // This maths copes with reading rows in any order. Turning on/off

            // at site level counts 1, at next level down 4, at next level 9,

            // then 16, etc. This means the deepest level always wins, except

            // against the -9999 at top level.

            $courseactive[$row->filter] +=

                ($depth + 1) * ($depth + 1) * $row->active;

            if ($row->active == TEXTFILTER_DISABLED) {

                $banned[$row->filter] = true;

            }

        } else {

            // Build list of other rows indexed by contextid.

            if (!array_key_exists($row->contextid, $remainingactives)) {

                $remainingactives[$row->contextid] = array();

            }

            $remainingactives[$row->contextid][] = $row;

        }

    }

    // Chuck away the ones that aren't active.

    foreach ($courseactive as $filter => $score) {

        if ($score <= 0) {

            unset($courseactive[$filter]);

        } else {

            $courseactive[$filter] = array();

        }

    }

    // Loop through the contexts to reconstruct filter_active lists for each

    // cm on the course.

    if (!isset($FILTERLIB_PRIVATE->active)) {

        $FILTERLIB_PRIVATE->active = array();

    }

    foreach ($cmcontextids as $contextid) {

        // Copy course list.

        $FILTERLIB_PRIVATE->active[$contextid] = $courseactive;

        // Are there any changes to the active list?

        if (array_key_exists($contextid, $remainingactives)) {

            foreach ($remainingactives[$contextid] as $row) {

                if ($row->active > 0 && empty($banned[$row->filter])) {

                    // If it's marked active for specific context, add entry

                    // (doesn't matter if one exists already).

                    $FILTERLIB_PRIVATE->active[$contextid][$row->filter] = array();

                } else {

                    // If it's marked inactive, remove entry (doesn't matter

                    // if it doesn't exist).

                    unset($FILTERLIB_PRIVATE->active[$contextid][$row->filter]);

                }

            }

        }

    }

    // Process all config rows to add config data to these entries.

    foreach ($filterconfigs as $row) {

        if (isset($FILTERLIB_PRIVATE->active[$row->contextid][$row->filter])) {

            $FILTERLIB_PRIVATE->active[$row->contextid][$row->filter][$row->name] = $row->value;

        }

    }

}

/**

 * List all of the filters that are available in this context, and what the

 * local and inherited states of that filter are.

 *

 * @param context $context a context that is not the system context.

 * @return array an array with filter names, for example 'tex'

 *      as keys. and and the values are objects with fields:

 *      ->filter filter name, same as the key.

 *      ->localstate TEXTFILTER_ON/OFF/INHERIT

 *      ->inheritedstate TEXTFILTER_ON/OFF - the state that will be used if localstate is set to TEXTFILTER_INHERIT.

 */

function filter_get_available_in_context($context) {

    global $DB;

    // The complex logic is working out the active state in the parent context,

    // so strip the current context from the list.

    $contextids = explode('/', trim($context->path, '/'));

    array_pop($contextids);

    $contextids = implode(',', $contextids);

    if (empty($contextids)) {

        throw new coding_exception('filter_get_available_in_context cannot be called with the system context.');

    }

    // The following SQL is tricky, in the same way at the SQL in filter_get_active_in_context.

    $sql = "SELECT parent_states.filter,

                CASE WHEN fa.active IS NULL THEN " . TEXTFILTER_INHERIT . "

                ELSE fa.active END AS localstate,

             parent_states.inheritedstate

         FROM (SELECT f.filter, MAX(f.sortorder) AS sortorder,

                    CASE WHEN MAX(f.active * ctx.depth) > -MIN(f.active * ctx.depth) THEN " . TEXTFILTER_ON . "

                    ELSE " . TEXTFILTER_OFF . " END AS inheritedstate

             FROM {filter_active} f

             JOIN {context} ctx ON f.contextid = ctx.id

             WHERE ctx.id IN ($contextids)

             GROUP BY f.filter

             HAVING MIN(f.active) > " . TEXTFILTER_DISABLED . "

         ) parent_states

         LEFT JOIN {filter_active} fa ON fa.filter = parent_states.filter AND fa.contextid = $context->id

         ORDER BY parent_states.sortorder";

    return $DB->get_records_sql($sql);

}

/**

 * This function is for use by the filter administration page.

 *

 * @return array 'filtername' => object with fields 'filter' (=filtername), 'active' and 'sortorder'

 */

function filter_get_global_states() {

    global $DB;

    $context = context_system::instance();

    return $DB->get_records('filter_active', array('contextid' => $context->id), 'sortorder', 'filter,active,sortorder');

}

/**

 * Retrieve all the filters and their states (including overridden ones in any context).

 *

 * @return array filters objects containing filter name, context, active state and sort order.

 */

function filter_get_all_states(): array {

    global $DB;

    return $DB->get_records('filter_active');

}

/**

 * Delete all the data in the database relating to a filter, prior to deleting it.

 *

 * @param string $filter The filter name, for example 'tex'.

 */

function filter_delete_all_for_filter($filter) {

    global $DB;

    unset_all_config_for_plugin('filter_' . $filter);

    $DB->delete_records('filter_active', array('filter' => $filter));

    $DB->delete_records('filter_config', array('filter' => $filter));

}

/**

 * Delete all the data in the database relating to a context, used when contexts are deleted.

 *

 * @param integer $contextid The id of the context being deleted.

 */

function filter_delete_all_for_context($contextid) {

    global $DB;

    $DB->delete_records('filter_active', array('contextid' => $contextid));

    $DB->delete_records('filter_config', array('contextid' => $contextid));

}

/**

 * Does this filter have a global settings page in the admin tree?

 * (The settings page for a filter must be called, for example, filtersettingfiltertex.)

 *

 * @param string $filter The filter name, for example 'tex'.

 * @return boolean Whether there should be a 'Settings' link on the config page.

 */

function filter_has_global_settings($filter) {

    global $CFG;

    $settingspath = $CFG->dirroot . '/filter/' . $filter . '/settings.php';

    if (is_readable($settingspath)) {

        return true;

    }

    $settingspath = $CFG->dirroot . '/filter/' . $filter . '/filtersettings.php';

    return is_readable($settingspath);

}

/**

 * Does this filter have local (per-context) settings?

 *

 * @param string $filter The filter name, for example 'tex'.

 * @return boolean Whether there should be a 'Settings' link on the manage filters in context page.

 */

function filter_has_local_settings($filter) {

    global $CFG;

    $settingspath = $CFG->dirroot . '/filter/' . $filter . '/filterlocalsettings.php';

    return is_readable($settingspath);

}

/**

 * Certain types of context (block and user) may not have local filter settings.

 * the function checks a context to see whether it may have local config.

 *

 * @param object $context a context.

 * @return boolean whether this context may have local filter settings.

 */

function filter_context_may_have_filter_settings($context) {

    return $context->contextlevel != CONTEXT_BLOCK && $context->contextlevel != CONTEXT_USER;

}

/**

 * Process phrases intelligently found within a HTML text (such as adding links).

 *

 * @param string $text            the text that we are filtering

 * @param filterobject[] $linkarray an array of filterobjects

 * @param array $ignoretagsopen   an array of opening tags that we should ignore while filtering

 * @param array $ignoretagsclose  an array of corresponding closing tags

 * @param bool $overridedefaultignore True to only use tags provided by arguments

 * @param bool $linkarrayalreadyprepared True to say that filter_prepare_phrases_for_filtering

 *      has already been called for $linkarray. Default false.

 * @return string

 */

function filter_phrases($text, $linkarray, $ignoretagsopen = null, $ignoretagsclose = null,

        $overridedefaultignore = false, $linkarrayalreadyprepared = false) {

    global $CFG;

    // Used if $CFG->filtermatchoneperpage is on. Array with keys being the workregexp

    // for things that have already been matched on this page.

    static $usedphrases = [];

    $ignoretags = array();  // To store all the enclosing tags to be completely ignored.

    $tags = array();        // To store all the simple tags to be ignored.

    if (!$linkarrayalreadyprepared) {

        $linkarray = filter_prepare_phrases_for_filtering($linkarray);

    }

    if (!$overridedefaultignore) {

        // A list of open/close tags that we should not replace within.

        // Extended to include <script>, <textarea>, <select> and <a> tags.

        // Regular expression allows tags with or without attributes.

        $filterignoretagsopen  = array('<head>', '<nolink>', '<span(\s[^>]*?)?class="nolink"(\s[^>]*?)?>',

                '<script(\s[^>]*?)?>', '<textarea(\s[^>]*?)?>',

                '<select(\s[^>]*?)?>', '<a(\s[^>]*?)?>');

        $filterignoretagsclose = array('</head>', '</nolink>', '</span>',

                 '</script>', '</textarea>', '</select>', '</a>');

    } else {

        // Set an empty default list.

        $filterignoretagsopen = array();

        $filterignoretagsclose = array();

    }

    // Add the user defined ignore tags to the default list.

    if ( is_array($ignoretagsopen) ) {

        foreach ($ignoretagsopen as $open) {

            $filterignoretagsopen[] = $open;

        }

        foreach ($ignoretagsclose as $close) {

            $filterignoretagsclose[] = $close;

        }

    }

    // Double up some magic chars to avoid "accidental matches".

    $text = preg_replace('/([#*%])/', '\1\1', $text);

    // Remove everything enclosed by the ignore tags from $text.

    filter_save_ignore_tags($text, $filterignoretagsopen, $filterignoretagsclose, $ignoretags);

    // Remove tags from $text.

    filter_save_tags($text, $tags);

    // Prepare the limit for preg_match calls.

    if (!empty($CFG->filtermatchonepertext) || !empty($CFG->filtermatchoneperpage)) {

        $pregreplacelimit = 1;

    } else {

        $pregreplacelimit = -1; // No limit.

    }

    // Time to cycle through each phrase to be linked.

    foreach ($linkarray as $key => $linkobject) {

        if ($linkobject->workregexp === null) {

            // This is the case if, when preparing the phrases for filtering,

            // we decided that this was not a suitable phrase to match.

            continue;

        }

        // If $CFG->filtermatchoneperpage, avoid previously matched linked phrases.

        if (!empty($CFG->filtermatchoneperpage) && isset($usedphrases[$linkobject->workregexp])) {

            continue;

        }

        // Do our highlighting.

        $resulttext = preg_replace_callback($linkobject->workregexp,

                function ($matches) use ($linkobject) {

                    if ($linkobject->workreplacementphrase === null) {

                        filter_prepare_phrase_for_replacement($linkobject);

                    }

                    return str_replace('$1', $matches[1], $linkobject->workreplacementphrase);

                }, $text, $pregreplacelimit);

        // If the text has changed we have to look for links again.

        if ($resulttext != $text) {

            $text = $resulttext;

            // Remove everything enclosed by the ignore tags from $text.

            filter_save_ignore_tags($text, $filterignoretagsopen, $filterignoretagsclose, $ignoretags);

            // Remove tags from $text.

            filter_save_tags($text, $tags);

            // If $CFG->filtermatchoneperpage, save linked phrases to request.

            if (!empty($CFG->filtermatchoneperpage)) {

                $usedphrases[$linkobject->workregexp] = 1;

            }

        }

    }

    // Rebuild the text with all the excluded areas.

    if (!empty($tags)) {

        $text = str_replace(array_keys($tags), $tags, $text);

    }

    if (!empty($ignoretags)) {

        $ignoretags = array_reverse($ignoretags);     // Reversed so "progressive" str_replace() will solve some nesting problems.

        $text = str_replace(array_keys($ignoretags), $ignoretags, $text);

    }

    // Remove the protective doubleups.

    $text = preg_replace('/([#*%])(\1)/', '\1', $text);

    // Add missing javascript for popus.

    $text = filter_add_javascript($text);

    return $text;

}

/**

 * Prepare a list of link for processing with {@link filter_phrases()}.

 *

 * @param filterobject[] $linkarray the links that will be passed to filter_phrases().

 * @return filterobject[] the updated list of links with necessary pre-processing done.

 */

function filter_prepare_phrases_for_filtering(array $linkarray) {

    // Time to cycle through each phrase to be linked.

    foreach ($linkarray as $linkobject) {

        // Set some defaults if certain properties are missing.

        // Properties may be missing if the filterobject class has not been used to construct the object.

        if (empty($linkobject->phrase)) {

            continue;

        }

        // Avoid integers < 1000 to be linked. See bug 1446.

        $intcurrent = intval($linkobject->phrase);

        if (!empty($intcurrent) && strval($intcurrent) == $linkobject->phrase && $intcurrent < 1000) {

            continue;

        }

        // Strip tags out of the phrase.

        $linkobject->workregexp = strip_tags($linkobject->phrase);

        if (!$linkobject->casesensitive) {

            $linkobject->workregexp = core_text::strtolower($linkobject->workregexp);

        }

        // Double up chars that might cause a false match -- the duplicates will

        // be cleared up before returning to the user.

        $linkobject->workregexp = preg_replace('/([#*%])/', '\1\1', $linkobject->workregexp);

        // Quote any regular expression characters and the delimiter in the work phrase to be searched.

        $linkobject->workregexp = preg_quote($linkobject->workregexp, '/');

        // If we ony want to match entire words then add \b assertions. However, only

        // do this if the first or last thing in the phrase to match is a word character.

        if ($linkobject->fullmatch) {

            if (preg_match('~^\w~', $linkobject->workregexp)) {

                $linkobject->workregexp = '\b' . $linkobject->workregexp;

            }