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Differences Between: [Versions 39 and 401] [Versions 39 and 402] [Versions 39 and 403]

   1  <?php
   2  
   3  // This file is part of Moodle - http://moodle.org/
   4  //
   5  // Moodle is free software: you can redistribute it and/or modify
   6  // it under the terms of the GNU General Public License as published by
   7  // the Free Software Foundation, either version 3 of the License, or
   8  // (at your option) any later version.
   9  //
  10  // Moodle is distributed in the hope that it will be useful,
  11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  // GNU General Public License for more details.
  14  //
  15  // You should have received a copy of the GNU General Public License
  16  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17  
  18  /**
  19   * Classes for displaying and editing a nested list of items.
  20   *
  21   * Handles functionality for :
  22   *
  23   *    Construction of nested list from db records with some key pointing to a parent id.
  24   *    Display of list with or without editing icons with optional pagination.
  25   *    Reordering of items works across pages.
  26   *    Processing of editing actions on list.
  27   *
  28   * @package    core
  29   * @subpackage lib
  30   * @copyright  Jamie Pratt
  31   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  32   */
  33  
  34  defined('MOODLE_INTERNAL') || die();
  35  
  36  /**
  37   * Clues to reading this code:
  38   *
  39   * The functions that move things around the tree structure just update the
  40   * database - they don't update the in-memory structure, instead they trigger a
  41   * page reload so everything is rebuilt from scratch.
  42   *
  43   * @package moodlecore
  44   * @copyright Jamie Pratt
  45   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  46   */
  47  abstract class moodle_list {
  48      public $attributes;
  49      public $listitemclassname = 'list_item';
  50  
  51      /** @var array of $listitemclassname objects. */
  52      public $items = array();
  53  
  54      /** @var string 'ol' or 'ul'. */
  55      public $type;
  56  
  57      /** @var list_item or derived class. */
  58      public $parentitem = null;
  59      public $table;
  60      public $fieldnamesparent = 'parent';
  61  
  62      /** @var array Records from db, only used in top level list. */
  63      public $records = array();
  64  
  65      public $editable;
  66  
  67      /** @var array keys are child ids, values are parents. */
  68      public $childparent;
  69  
  70  //------------------------------------------------------
  71  //vars used for pagination.
  72      public $page = 0; // 0 means no pagination
  73      public $firstitem = 1;
  74      public $lastitem = 999999;
  75      public $pagecount;
  76      public $paged = false;
  77      public $offset = 0;
  78  //------------------------------------------------------
  79      public $pageurl;
  80      public $pageparamname;
  81  
  82      /**
  83       * Constructor.
  84       *
  85       * @param string $type
  86       * @param string $attributes
  87       * @param boolean $editable
  88       * @param moodle_url $pageurl url for this page
  89       * @param integer $page if 0 no pagination. (These three params only used in top level list.)
  90       * @param string $pageparamname name of url param that is used for passing page no
  91       * @param integer $itemsperpage no of top level items.
  92       */
  93      public function __construct($type='ul', $attributes='', $editable = false, $pageurl=null, $page = 0, $pageparamname = 'page', $itemsperpage = 20) {
  94          global $PAGE;
  95  
  96          $this->editable = $editable;
  97          $this->attributes = $attributes;
  98          $this->type = $type;
  99          $this->page = $page;
 100          $this->pageparamname = $pageparamname;
 101          $this->itemsperpage = $itemsperpage;
 102          if ($pageurl === null) {
 103              $this->pageurl = new moodle_url($PAGE->url);
 104              $this->pageurl->params(array($this->pageparamname => $this->page));
 105          } else {
 106              $this->pageurl = $pageurl;
 107          }
 108      }
 109  
 110      /**
 111       * Returns html string.
 112       *
 113       * @param integer $indent depth of indentation.
 114       */
 115      public function to_html($indent=0, $extraargs=array()) {
 116          if (count($this->items)) {
 117              $tabs = str_repeat("\t", $indent);
 118              $first = true;
 119              $itemiter = 1;
 120              $lastitem = '';
 121              $html = '';
 122  
 123              foreach ($this->items as $item) {
 124                  $last = (count($this->items) == $itemiter);
 125                  if ($this->editable) {
 126                      $item->set_icon_html($first, $last, $lastitem);
 127                  }
 128                  if ($itemhtml = $item->to_html($indent+1, $extraargs)) {
 129                      $html .= "$tabs\t<li".((!empty($item->attributes))?(' '.$item->attributes):'').">";
 130                      $html .= $itemhtml;
 131                      $html .= "</li>\n";
 132                  }
 133                  $first = false;
 134                  $lastitem = $item;
 135                  $itemiter++;
 136              }
 137          } else {
 138              $html = '';
 139          }
 140          if ($html) { //if there are list items to display then wrap them in ul / ol tag.
 141              $tabs = str_repeat("\t", $indent);
 142              $html = $tabs.'<'.$this->type.((!empty($this->attributes))?(' '.$this->attributes):'').">\n".$html;
 143              $html .= $tabs."</".$this->type.">\n";
 144          } else {
 145              $html ='';
 146          }
 147          return $html;
 148      }
 149  
 150      /**
 151       * Recurse down the tree and find an item by it's id.
 152       *
 153       * @param integer $id
 154       * @param boolean $suppresserror error if not item found?
 155       * @return list_item *copy* or null if item is not found
 156       */
 157      public function find_item($id, $suppresserror = false) {
 158          if (isset($this->items)) {
 159              foreach ($this->items as $key => $child) {
 160                  if ($child->id == $id) {
 161                      return $this->items[$key];
 162                  }
 163              }
 164              foreach (array_keys($this->items) as $key) {
 165                  $thischild = $this->items[$key];
 166                  $ref = $thischild->children->find_item($id, true);//error always reported at top level
 167                  if ($ref !== null) {
 168                      return $ref;
 169                  }
 170              }
 171          }
 172  
 173          if (!$suppresserror) {
 174              print_error('listnoitem');
 175          }
 176          return null;
 177      }
 178  
 179      public function add_item($item) {
 180          $this->items[] = $item;
 181      }
 182  
 183      public function set_parent($parent) {
 184          $this->parentitem = $parent;
 185      }
 186  
 187      /**
 188       * Produces a hierarchical tree of list items from a flat array of records.
 189       * 'parent' field is expected to point to a parent record.
 190       * records are already sorted.
 191       * If the parent field doesn't point to another record in the array then this is
 192       * a top level list
 193       *
 194       * @param integer $offset how many list toplevel items are there in lists before this one
 195       * @return array(boolean, integer) whether there is more than one page, $offset + how many toplevel items where there in this list.
 196       *
 197       */
 198      public function list_from_records($paged = false, $offset = 0) {
 199          $this->paged = $paged;
 200          $this->offset = $offset;
 201          $this->get_records();
 202          $records = $this->records;
 203          $page = $this->page;
 204          if (!empty($page)) {
 205              $this->firstitem = ($page - 1) * $this->itemsperpage;
 206              $this->lastitem = $this->firstitem + $this->itemsperpage - 1;
 207          }
 208          $itemiter = $offset;
 209          //make a simple array which is easier to search
 210          $this->childparent = array();
 211          foreach ($records as $record) {
 212              $this->childparent[$record->id] = $record->parent;
 213          }
 214  
 215          //create top level list items and they're responsible for creating their children
 216          foreach ($records as $record) {
 217              if (array_key_exists($record->parent, $this->childparent)) {
 218                  // This record is a child of another record, so it will be dealt
 219                  // with by a call to list_item::create_children, not here.
 220                  continue;
 221              }
 222  
 223              $inpage = $itemiter >= $this->firstitem && $itemiter <= $this->lastitem;
 224  
 225              // Make list item for top level for all items
 226              // we need the info about the top level items for reordering peers.
 227              if ($this->parentitem !== null) {
 228                  $newattributes = $this->parentitem->attributes;
 229              } else {
 230                  $newattributes = '';
 231              }
 232  
 233              $this->items[$itemiter] = new $this->listitemclassname($record, $this, $newattributes, $inpage);
 234  
 235              if ($inpage) {
 236                  $this->items[$itemiter]->create_children($records, $this->childparent, $record->id);
 237              } else {
 238                  // Don't recurse down the tree for items that are not on this page
 239                  $this->paged = true;
 240              }
 241  
 242              $itemiter++;
 243          }
 244          return array($this->paged, $itemiter);
 245      }
 246  
 247      /**
 248       * Should be overriden to return an array of records of list items.
 249       */
 250      public abstract function get_records();
 251  
 252      /**
 253       * display list of page numbers for navigation
 254       */
 255      public function display_page_numbers() {
 256          $html = '';
 257          $topcount = count($this->items);
 258          $this->pagecount = (integer) ceil(($topcount + $this->offset)/ QUESTION_PAGE_LENGTH );
 259          if (!empty($this->page) && ($this->paged)) {
 260              $html = "<div class=\"paging\">".get_string('page').":\n";
 261              foreach (range(1,$this->pagecount) as $currentpage) {
 262                  if ($this->page == $currentpage) {
 263                      $html .= " $currentpage \n";
 264                  }
 265                  else {
 266                      $html .= "<a href=\"".$this->pageurl->out(true, array($this->pageparamname => $currentpage))."\">";
 267                      $html .= " $currentpage </a>\n";
 268                  }
 269              }
 270              $html .= "</div>";
 271          }
 272          return $html;
 273      }
 274  
 275      /**
 276       * Returns an array of ids of peers of an item.
 277       *
 278       * @param    int itemid - if given, restrict records to those with this parent id.
 279       * @return   array peer ids
 280       */
 281      public function get_items_peers($itemid) {
 282          $itemref = $this->find_item($itemid);
 283          $peerids = $itemref->parentlist->get_child_ids();
 284          return $peerids;
 285      }
 286  
 287      /**
 288       * Returns an array of ids of child items.
 289       *
 290       * @return   array peer ids
 291       */
 292      public function get_child_ids() {
 293          $childids = array();
 294          foreach ($this->items as $child) {
 295             $childids[] = $child->id;
 296          }
 297          return $childids;
 298      }
 299  
 300      /**
 301       * Returns the value to be used as the parent for the $item when it goes to the top level.
 302       * Override if needed.
 303       *
 304       * @param list_item $item The item which its top level parent is going to be returned.
 305       * @return int
 306       */
 307      public function get_top_level_parent_id($item) {
 308          return 0; // Top level items have no parent.
 309      }
 310  
 311      /**
 312       * Move a record up or down
 313       *
 314       * @param string $direction up / down
 315       * @param integer $id
 316       */
 317      public function move_item_up_down($direction, $id) {
 318          $peers = $this->get_items_peers($id);
 319          $itemkey = array_search($id, $peers);
 320          switch ($direction) {
 321              case 'down' :
 322                  if (isset($peers[$itemkey+1])) {
 323                      $olditem = $peers[$itemkey+1];
 324                      $peers[$itemkey+1] = $id;
 325                      $peers[$itemkey] = $olditem;
 326                  } else {
 327                      print_error('listcantmoveup');
 328                  }
 329                  break;
 330  
 331              case 'up' :
 332                  if (isset($peers[$itemkey-1])) {
 333                      $olditem = $peers[$itemkey-1];
 334                      $peers[$itemkey-1] = $id;
 335                      $peers[$itemkey] = $olditem;
 336                  } else {
 337                      print_error('listcantmovedown');
 338                  }
 339                  break;
 340          }
 341          $this->reorder_peers($peers);
 342      }
 343  
 344      public function reorder_peers($peers) {
 345          global $DB;
 346          foreach ($peers as $key => $peer) {
 347              $DB->set_field($this->table, "sortorder", $key, array("id"=>$peer));
 348          }
 349      }
 350  
 351      /**
 352       * Moves the item one step up in the tree.
 353       *
 354       * @param int $id an item index.
 355       * @return list_item the item that used to be the parent of the item moved.
 356       */
 357      public function move_item_left($id) {
 358          global $DB;
 359  
 360          $item = $this->find_item($id);
 361          if (!isset($item->parentlist->parentitem->parentlist)) {
 362              print_error('listcantmoveleft');
 363          } else {
 364              $newpeers = $this->get_items_peers($item->parentlist->parentitem->id);
 365              if (isset($item->parentlist->parentitem->parentlist->parentitem)) {
 366                  $newparent = $item->parentlist->parentitem->parentlist->parentitem->id;
 367              } else {
 368                  $newparent = $this->get_top_level_parent_id($item);
 369              }
 370              $DB->set_field($this->table, "parent", $newparent, array("id"=>$item->id));
 371              $oldparentkey = array_search($item->parentlist->parentitem->id, $newpeers);
 372              $neworder = array_merge(array_slice($newpeers, 0, $oldparentkey+1), array($item->id), array_slice($newpeers, $oldparentkey+1));
 373              $this->reorder_peers($neworder);
 374          }
 375          return $item->parentlist->parentitem;
 376      }
 377  
 378      /**
 379       * Make item with id $id the child of the peer that is just above it in the sort order.
 380       *
 381       * @param integer $id
 382       */
 383      public function move_item_right($id) {
 384          global $DB;
 385  
 386          $peers = $this->get_items_peers($id);
 387          $itemkey = array_search($id, $peers);
 388          if (!isset($peers[$itemkey-1])) {
 389              print_error('listcantmoveright');
 390          } else {
 391              $DB->set_field($this->table, "parent", $peers[$itemkey-1], array("id"=>$peers[$itemkey]));
 392              $newparent = $this->find_item($peers[$itemkey-1]);
 393              if (isset($newparent->children)) {
 394                  $newpeers = $newparent->children->get_child_ids();
 395              }
 396              if ($newpeers) {
 397                  $newpeers[] = $peers[$itemkey];
 398                  $this->reorder_peers($newpeers);
 399              }
 400          }
 401      }
 402  
 403      /**
 404       * process any actions.
 405       *
 406       * @param integer $left id of item to move left
 407       * @param integer $right id of item to move right
 408       * @param integer $moveup id of item to move up
 409       * @param integer $movedown id of item to move down
 410       * @return unknown
 411       */
 412      public function process_actions($left, $right, $moveup, $movedown) {
 413          //should this action be processed by this list object?
 414          if (!(array_key_exists($left, $this->records) || array_key_exists($right, $this->records) || array_key_exists($moveup, $this->records) || array_key_exists($movedown, $this->records))) {
 415              return false;
 416          }
 417          if (!empty($left)) {
 418              $oldparentitem = $this->move_item_left($left);
 419              if ($this->item_is_last_on_page($oldparentitem->id)) {
 420                  // Item has jumped onto the next page, change page when we redirect.
 421                  $this->page ++;
 422                  $this->pageurl->params(array($this->pageparamname => $this->page));
 423              }
 424          } else if (!empty($right)) {
 425              $this->move_item_right($right);
 426              if ($this->item_is_first_on_page($right)) {
 427                  // Item has jumped onto the previous page, change page when we redirect.
 428                  $this->page --;
 429                  $this->pageurl->params(array($this->pageparamname => $this->page));
 430              }
 431          } else if (!empty($moveup)) {
 432              $this->move_item_up_down('up', $moveup);
 433              if ($this->item_is_first_on_page($moveup)) {
 434                  // Item has jumped onto the previous page, change page when we redirect.
 435                  $this->page --;
 436                  $this->pageurl->params(array($this->pageparamname => $this->page));
 437              }
 438          } else if (!empty($movedown)) {
 439              $this->move_item_up_down('down', $movedown);
 440              if ($this->item_is_last_on_page($movedown)) {
 441                  // Item has jumped onto the next page, change page when we redirect.
 442                  $this->page ++;
 443                  $this->pageurl->params(array($this->pageparamname => $this->page));
 444              }
 445          } else {
 446              return false;
 447          }
 448  
 449          redirect($this->pageurl);
 450      }
 451  
 452      /**
 453       * @param integer $itemid an item id.
 454       * @return boolean Is the item with the given id the first top-level item on
 455       * the current page?
 456       */
 457      public function item_is_first_on_page($itemid) {
 458          return $this->page && isset($this->items[$this->firstitem]) &&
 459                  $itemid == $this->items[$this->firstitem]->id;
 460      }
 461  
 462      /**
 463       * @param integer $itemid an item id.
 464       * @return boolean Is the item with the given id the last top-level item on
 465       * the current page?
 466       */
 467      public function item_is_last_on_page($itemid) {
 468          return $this->page && isset($this->items[$this->lastitem]) &&
 469                  $itemid == $this->items[$this->lastitem]->id;
 470      }
 471  }
 472  
 473  /**
 474   * @package moodlecore
 475   * @copyright Jamie Pratt
 476   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 477   */
 478  abstract class list_item {
 479      /** @var integer id of record, used if list is editable. */
 480      public $id;
 481  
 482      /** @var string name of this item, used if list is editable. */
 483      public $name;
 484  
 485      /** @var mixed The object or string representing this item. */
 486      public $item;
 487      public $fieldnamesname = 'name';
 488      public $attributes;
 489      public $display;
 490      public $icons = array();
 491  
 492      /** @var moodle_list */
 493      public $parentlist;
 494  
 495      /** @var moodle_list Set if there are any children of this listitem. */
 496      public $children;
 497  
 498      /**
 499       * Constructor
 500       * @param mixed $item fragment of html for list item or record
 501       * @param object $parent reference to parent of this item
 502       * @param string $attributes attributes for li tag
 503       * @param boolean $display whether this item is displayed. Some items may be loaded so we have a complete
 504       *                              structure in memory to work with for actions but are not displayed.
 505       * @return list_item
 506       */
 507      public function __construct($item, $parent, $attributes = '', $display = true) {
 508          $this->item = $item;
 509          if (is_object($this->item)) {
 510              $this->id = $this->item->id;
 511              $this->name = $this->item->{$this->fieldnamesname};
 512          }
 513          $this->set_parent($parent);
 514          $this->attributes = $attributes;
 515          $parentlistclass = get_class($parent);
 516          $this->children = new $parentlistclass($parent->type, $parent->attributes, $parent->editable, $parent->pageurl, 0);
 517          $this->children->set_parent($this);
 518          $this->display = $display;
 519      }
 520  
 521      /**
 522       * Output the html just for this item. Called by to_html which adds html for children.
 523       *
 524       */
 525      public function item_html($extraargs = array()) {
 526          if (is_string($this->item)) {
 527              $html = $this->item;
 528          } elseif (is_object($this->item)) {
 529              //for debug purposes only. You should create a sub class to
 530              //properly handle the record
 531              $html = join(', ', (array)$this->item);
 532          }
 533          return $html;
 534      }
 535  
 536      /**
 537       * Returns html
 538       *
 539       * @param integer $indent
 540       * @param array $extraargs any extra data that is needed to print the list item
 541       *                            may be used by sub class.
 542       * @return string html
 543       */
 544      public function to_html($indent = 0, $extraargs = array()) {
 545          if (!$this->display) {
 546              return '';
 547          }
 548          $tabs = str_repeat("\t", $indent);
 549  
 550          if (isset($this->children)) {
 551              $childrenhtml = $this->children->to_html($indent+1, $extraargs);
 552          } else {
 553              $childrenhtml = '';
 554          }
 555          return $this->item_html($extraargs).'&nbsp;'.(join('', $this->icons)).(($childrenhtml !='')?("\n".$childrenhtml):'');
 556      }
 557  
 558      public function set_icon_html($first, $last, $lastitem) {
 559          global $CFG;
 560          $strmoveup = get_string('moveup');
 561          $strmovedown = get_string('movedown');
 562          $strmoveleft = get_string('maketoplevelitem', 'question');
 563  
 564          if (right_to_left()) {   // Exchange arrows on RTL
 565              $rightarrow = 'left';
 566              $leftarrow  = 'right';
 567          } else {
 568              $rightarrow = 'right';
 569              $leftarrow  = 'left';
 570          }
 571  
 572          if (isset($this->parentlist->parentitem)) {
 573              $parentitem = $this->parentlist->parentitem;
 574              if (isset($parentitem->parentlist->parentitem)) {
 575                  $action = get_string('makechildof', 'question', $parentitem->parentlist->parentitem->name);
 576              } else {
 577                  $action = $strmoveleft;
 578              }
 579              $url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'left'=>$this->id)));
 580              $this->icons['left'] = $this->image_icon($action, $url, $leftarrow);
 581          } else {
 582              $this->icons['left'] =  $this->image_spacer();
 583          }
 584  
 585          if (!$first) {
 586              $url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'moveup'=>$this->id)));
 587              $this->icons['up'] = $this->image_icon($strmoveup, $url, 'up');
 588          } else {
 589              $this->icons['up'] =  $this->image_spacer();
 590          }
 591  
 592          if (!$last) {
 593              $url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'movedown'=>$this->id)));
 594              $this->icons['down'] = $this->image_icon($strmovedown, $url, 'down');
 595          } else {
 596              $this->icons['down'] =  $this->image_spacer();
 597          }
 598  
 599          if (!empty($lastitem)) {
 600              $makechildof = get_string('makechildof', 'question', $lastitem->name);
 601              $url = new moodle_url($this->parentlist->pageurl, (array('sesskey'=>sesskey(), 'right'=>$this->id)));
 602              $this->icons['right'] = $this->image_icon($makechildof, $url, $rightarrow);
 603          } else {
 604              $this->icons['right'] =  $this->image_spacer();
 605          }
 606      }
 607  
 608      public function image_icon($action, $url, $icon) {
 609          global $OUTPUT;
 610          return '<a title="' . s($action) .'" href="'.$url.'">' .
 611                  $OUTPUT->pix_icon('t/' . $icon, $action) . '</a> ';
 612      }
 613  
 614      public function image_spacer() {
 615          global $OUTPUT;
 616          return $OUTPUT->spacer();
 617      }
 618  
 619      /**
 620       * Recurse down tree creating list_items, called from moodle_list::list_from_records
 621       *
 622       * @param array $records
 623       * @param array $children
 624       * @param integer $thisrecordid
 625       */
 626      public function create_children(&$records, &$children, $thisrecordid) {
 627          //keys where value is $thisrecordid
 628          $thischildren = array_keys($children, $thisrecordid);
 629          foreach ($thischildren as $child) {
 630              $thisclass = get_class($this);
 631              $newlistitem = new $thisclass($records[$child], $this->children, $this->attributes);
 632              $this->children->add_item($newlistitem);
 633              $newlistitem->create_children($records, $children, $records[$child]->id);
 634          }
 635      }
 636  
 637      public function set_parent($parent) {
 638          $this->parentlist = $parent;
 639      }
 640  }