Current File : /home/vacivi36/ava/admin/tool/customlang/classes/local/mlang/phpparser.php
<?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/>.
/**
* Mlang PHP based on David Mudrak phpparser for local_amos.
*
* @package tool_customlang
* @copyright 2020 Ferran Recio <ferran@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace tool_customlang\local\mlang;
use coding_exception;
use moodle_exception;
/**
* Parser of Moodle strings defined as associative array.
*
* Moodle core just includes this file format directly as normal PHP code. However
* for security reasons, we must not do this for files uploaded by anonymous users.
* This parser reconstructs the associative $string array without actually including
* the file.
*/
class phpparser {
/** @var holds the singleton instance of self */
private static $instance = null;
/**
* Prevents direct creation of object
*/
private function __construct() {
}
/**
* Prevent from cloning the instance
*/
public function __clone() {
throw new coding_exception('Cloning os singleton is not allowed');
}
/**
* Get the singleton instance fo this class
*
* @return phpparser singleton instance of phpparser
*/
public static function get_instance(): phpparser {
if (is_null(self::$instance)) {
self::$instance = new phpparser();
}
return self::$instance;
}
/**
* Parses the given data in Moodle PHP string format
*
* Note: This method is adapted from local_amos as it is highly tested and robust.
* The priority is keeping it similar to the original one to make it easier to mantain.
*
* @param string $data definition of the associative array
* @param int $format the data format on the input, defaults to the one used since 2.0
* @return langstring[] array of langstrings of this file
*/
public function parse(string $data, int $format = 2): array {
$result = [];
$strings = $this->extract_strings($data);
foreach ($strings as $id => $text) {
$cleaned = clean_param($id, PARAM_STRINGID);
if ($cleaned !== $id) {
continue;
}
$text = langstring::fix_syntax($text, 2, $format);
$result[] = new langstring($id, $text);
}
return $result;
}
/**
* Low level parsing method
*
* Note: This method is adapted from local_amos as it is highly tested and robust.
* The priority is keeping it similar to the original one to make it easier to mantain.
*
* @param string $data
* @return string[] the data strings
*/
protected function extract_strings(string $data): array {
$strings = []; // To be returned.
if (empty($data)) {
return $strings;
}
// Tokenize data - we expect valid PHP code.
$tokens = token_get_all($data);
// Get rid of all non-relevant tokens.
$rubbish = [T_WHITESPACE, T_INLINE_HTML, T_COMMENT, T_DOC_COMMENT, T_OPEN_TAG, T_CLOSE_TAG];
foreach ($tokens as $i => $token) {
if (is_array($token)) {
if (in_array($token[0], $rubbish)) {
unset($tokens[$i]);
}
}
}
$id = null;
$text = null;
$line = 0;
$expect = 'STRING_VAR'; // The first expected token is '$string'.
// Iterate over tokens and look for valid $string array assignment patterns.
foreach ($tokens as $token) {
$foundtype = null;
$founddata = null;
if (is_array($token)) {
$foundtype = $token[0];
$founddata = $token[1];
if (!empty($token[2])) {
$line = $token[2];
}
} else {
$foundtype = 'char';
$founddata = $token;
}
if ($expect == 'STRING_VAR') {
if ($foundtype === T_VARIABLE and $founddata === '$string') {
$expect = 'LEFT_BRACKET';
continue;
} else {
// Allow other code at the global level.
continue;
}
}
if ($expect == 'LEFT_BRACKET') {
if ($foundtype === 'char' and $founddata === '[') {
$expect = 'STRING_ID';
continue;
} else {
throw new moodle_exception('Parsing error. Expected character [ at line '.$line);
}
}
if ($expect == 'STRING_ID') {
if ($foundtype === T_CONSTANT_ENCAPSED_STRING) {
$id = $this->decapsulate($founddata);
$expect = 'RIGHT_BRACKET';
continue;
} else {
throw new moodle_exception('Parsing error. Expected T_CONSTANT_ENCAPSED_STRING array key at line '.$line);
}
}
if ($expect == 'RIGHT_BRACKET') {
if ($foundtype === 'char' and $founddata === ']') {
$expect = 'ASSIGNMENT';
continue;
} else {
throw new moodle_exception('Parsing error. Expected character ] at line '.$line);
}
}
if ($expect == 'ASSIGNMENT') {
if ($foundtype === 'char' and $founddata === '=') {
$expect = 'STRING_TEXT';
continue;
} else {
throw new moodle_exception('Parsing error. Expected character = at line '.$line);
}
}
if ($expect == 'STRING_TEXT') {
if ($foundtype === T_CONSTANT_ENCAPSED_STRING) {
$text = $this->decapsulate($founddata);
$expect = 'SEMICOLON';
continue;
} else {
throw new moodle_exception(
'Parsing error. Expected T_CONSTANT_ENCAPSED_STRING array item value at line '.$line
);
}
}
if ($expect == 'SEMICOLON') {
if (is_null($id) or is_null($text)) {
throw new moodle_exception('Parsing error. NULL string id or value at line '.$line);
}
if ($foundtype === 'char' and $founddata === ';') {
if (!empty($id)) {
$strings[$id] = $text;
}
$id = null;
$text = null;
$expect = 'STRING_VAR';
continue;
} else {
throw new moodle_exception('Parsing error. Expected character ; at line '.$line);
}
}
}
return $strings;
}
/**
* Given one T_CONSTANT_ENCAPSED_STRING, return its value without quotes
*
* Also processes escaped quotes inside the text.
*
* Note: This method is taken directly from local_amos as it is highly tested and robust.
*
* @param string $text value obtained by token_get_all()
* @return string value without quotes
*/
protected function decapsulate(string $text): string {
if (strlen($text) < 2) {
throw new moodle_exception('Parsing error. Expected T_CONSTANT_ENCAPSED_STRING in decapsulate()');
}
if (substr($text, 0, 1) == "'" and substr($text, -1) == "'") {
// Single quoted string.
$text = trim($text, "'");
$text = str_replace("\'", "'", $text);
$text = str_replace('\\\\', '\\', $text);
return $text;
} else if (substr($text, 0, 1) == '"' and substr($text, -1) == '"') {
// Double quoted string.
$text = trim($text, '"');
$text = str_replace('\"', '"', $text);
$text = str_replace('\\\\', '\\', $text);
return $text;
} else {
throw new moodle_exception(
'Parsing error. Unexpected quotation in T_CONSTANT_ENCAPSED_STRING in decapsulate(): '.$text
);
}
}
}
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