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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * Language string based on David Mudrak langstring from local_amos.
  19   *
  20   * @package    tool_customlang
  21   * @copyright  2020 Ferran Recio <ferran@moodle.com>
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  namespace tool_customlang\local\mlang;
  26  
  27  use moodle_exception;
  28  use stdclass;
  29  
  30  /**
  31   * Class containing a lang string cleaned.
  32   *
  33   * @package    tool_customlang
  34   * @copyright  2020 Ferran Recio <ferran@moodle.com>
  35   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  36   */
  37  
  38  /**
  39   * Represents a single string
  40   */
  41  class langstring {
  42  
  43      /** @var string identifier */
  44      public $id = null;
  45  
  46      /** @var string */
  47      public $text = '';
  48  
  49      /** @var int the time stamp when this string was saved */
  50      public $timemodified = null;
  51  
  52      /** @var bool is deleted */
  53      public $deleted = false;
  54  
  55      /** @var stdclass extra information about the string */
  56      public $extra = null;
  57  
  58      /**
  59       * Class constructor.
  60       *
  61       * @param string $id string identifier
  62       * @param string $text string text
  63       * @param int $timemodified
  64       * @param int $deleted
  65       * @param stdclass $extra
  66       */
  67      public function __construct(string $id, string $text = '', int $timemodified = null,
  68              int $deleted = 0, stdclass $extra = null) {
  69  
  70          if (is_null($timemodified)) {
  71              $timemodified = time();
  72          }
  73          $this->id           = $id;
  74          $this->text         = $text;
  75          $this->timemodified = $timemodified;
  76          $this->deleted      = $deleted;
  77          $this->extra        = $extra;
  78      }
  79  
  80      /**
  81       * Given a string text, returns it being formatted properly for storing in AMOS repository.
  82       *
  83       * Note: This method is taken directly from local_amos as it is highly tested and robust.
  84       * The Moodle 1.x part is keep on puspose to make it easier the copy paste from both codes.
  85       * This could change in the future when AMOS stop suporting the 1.x langstrings.
  86       *
  87       * We need to know for what branch the string should be prepared due to internal changes in
  88       * format required by get_string()
  89       * - for get_string() in Moodle 1.6 - 1.9 use $format == 1
  90       * - for get_string() in Moodle 2.0 and higher use $format == 2
  91       *
  92       * Typical usages of this methods:
  93       *  $t = langstring::fix_syntax($t);          // sanity new translations of 2.x strings
  94       *  $t = langstring::fix_syntax($t, 1);       // sanity legacy 1.x strings
  95       *  $t = langstring::fix_syntax($t, 2, 1);    // convert format of 1.x strings into 2.x
  96       *
  97       * Backward converting 2.x format into 1.x is not supported
  98       *
  99       * @param string $text string text to be fixed
 100       * @param int $format target get_string() format version
 101       * @param int $from which format version does the text come from, defaults to the same as $format
 102       * @return string
 103       */
 104      public static function fix_syntax(string $text, int $format = 2, ?int $from = null): string {
 105          if (is_null($from)) {
 106              $from = $format;
 107          }
 108  
 109          // Common filter.
 110          $clean = trim($text);
 111          $search = [
 112              // Remove \r if it is part of \r\n.
 113              '/\r(?=\n)/',
 114  
 115              // Control characters to be replaced with \n
 116              // LINE TABULATION, FORM FEED, CARRIAGE RETURN, END OF TRANSMISSION BLOCK,
 117              // END OF MEDIUM, SUBSTITUTE, BREAK PERMITTED HERE, NEXT LINE, START OF STRING,
 118              // STRING TERMINATOR and Unicode character categorys Zl and Zp.
 119              '/[\x{0B}-\r\x{17}\x{19}\x{1A}\x{82}\x{85}\x{98}\x{9C}\p{Zl}\p{Zp}]/u',
 120  
 121              // Control characters to be removed
 122              // NULL, ENQUIRY, ACKNOWLEDGE, BELL, SHIFT {OUT,IN}, DATA LINK ESCAPE,
 123              // DEVICE CONTROL {ONE,TWO,THREE,FOUR}, NEGATIVE ACKNOWLEDGE, SYNCHRONOUS IDLE, ESCAPE,
 124              // DELETE, PADDING CHARACTER, HIGH OCTET PRESET, NO BREAK HERE, INDEX,
 125              // {START,END} OF SELECTED AREA, CHARACTER TABULATION {SET,WITH JUSTIFICATION},
 126              // LINE TABULATION SET, PARTIAL LINE {FORWARD,BACKWARD}, REVERSE LINE FEED,
 127              // SINGLE SHIFT {TWO,THREE}, DEVICE CONTROL STRING, PRIVATE USE {ONE,TWO},
 128              // SET TRANSMIT STATE, MESSAGE WAITING, {START,END} OF GUARDED AREA,
 129              // {SINGLE {GRAPHIC,} CHARACTER,CONTROL SEQUENCE} INTRODUCER, OPERATING SYSTEM COMMAND,
 130              // PRIVACY MESSAGE, APPLICATION PROGRAM COMMAND, ZERO WIDTH {,NO-BREAK} SPACE,
 131              // REPLACEMENT CHARACTER.
 132              '/[\0\x{05}-\x{07}\x{0E}-\x{16}\x{1B}\x{7F}\x{80}\x{81}\x{83}\x{84}\x{86}-\x{93}\x{95}-\x{97}\x{99}-\x{9B}\x{9D}-\x{9F}\x{200B}\x{FEFF}\x{FFFD}]++/u',
 133  
 134              // Remove trailing whitespace at the end of lines in a multiline string.
 135              '/[ \t]+(?=\n)/',
 136          ];
 137          $replace = [
 138              '',
 139              "\n",
 140              '',
 141              '',
 142          ];
 143          $clean = preg_replace($search, $replace, $clean);
 144  
 145          if (($format === 2) && ($from === 2)) {
 146              // Sanity translations of 2.x strings.
 147              $clean = preg_replace("/\n{3,}/", "\n\n\n", $clean); // Collapse runs of blank lines.
 148  
 149          } else if (($format === 2) && ($from === 1)) {
 150              // Convert 1.x string into 2.x format.
 151              $clean = preg_replace("/\n{3,}/", "\n\n\n", $clean); // Collapse runs of blank lines.
 152              $clean = preg_replace('/%+/', '%', $clean); // Collapse % characters.
 153              $clean = str_replace('\$', '@@@___XXX_ESCAPED_DOLLAR__@@@', $clean); // Remember for later.
 154              $clean = str_replace("\\", '', $clean); // Delete all slashes.
 155              $clean = preg_replace('/(^|[^{])\$a\b(\->[a-zA-Z0-9_]+)?/', '\\1{$a\\2}', $clean); // Wrap placeholders.
 156              $clean = str_replace('@@@___XXX_ESCAPED_DOLLAR__@@@', '$', $clean);
 157              $clean = str_replace('&#36;', '$', $clean);
 158  
 159          } else if (($format === 1) && ($from === 1)) {
 160              // Sanity legacy 1.x strings.
 161              $clean = preg_replace("/\n{3,}/", "\n\n", $clean); // Collapse runs of blank lines.
 162              $clean = str_replace('\$', '@@@___XXX_ESCAPED_DOLLAR__@@@', $clean);
 163              $clean = str_replace("\\", '', $clean); // Delete all slashes.
 164              $clean = str_replace('$', '\$', $clean); // Escape all embedded variables.
 165              // Unescape placeholders: only $a and $a->something are allowed. All other $variables are left escaped.
 166              $clean = preg_replace('/\\\\\$a\b(\->[a-zA-Z0-9_]+)?/', '$a\\1', $clean); // Unescape placeholders.
 167              $clean = str_replace('@@@___XXX_ESCAPED_DOLLAR__@@@', '\$', $clean);
 168              $clean = str_replace('"', "\\\"", $clean); // Add slashes for ".
 169              $clean = preg_replace('/%+/', '%', $clean); // Collapse % characters.
 170              $clean = str_replace('%', '%%', $clean); // Duplicate %.
 171  
 172          } else {
 173              throw new moodle_exception('Unknown get_string() format version');
 174          }
 175          return $clean;
 176      }
 177  }