mod/book/locallib.php

   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  * Book module local lib functions
  19  *
  20  * @package    mod_book
  21  * @copyright  2010-2011 Petr Skoda {@link http://skodak.org}
  22  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  */
  24
  25 defined('MOODLE_INTERNAL') || die;
  26
  27 require_once(__DIR__.'/lib.php');
  28 require_once($CFG->libdir.'/filelib.php');
  29
  30 /**
  31  * The following defines are used to define how the chapters and subchapters of a book should be displayed in that table of contents.
  32  * BOOK_NUM_NONE        No special styling will applied and the editor will be able to do what ever thay want in the title
  33  * BOOK_NUM_NUMBERS     Chapters and subchapters are numbered (1, 1.1, 1.2, 2, ...)
  34  * BOOK_NUM_BULLETS     Subchapters are indented and displayed with bullets
  35  * BOOK_NUM_INDENTED    Subchapters are indented
  36  */
  37 define('BOOK_NUM_NONE',     '0');
  38 define('BOOK_NUM_NUMBERS',  '1');
  39 define('BOOK_NUM_BULLETS',  '2');
  40 define('BOOK_NUM_INDENTED', '3');
  41
  42 /**
  43  * The following defines are used to define the navigation style used within a book.
  44  * BOOK_LINK_TOCONLY    Only the table of contents is shown, in a side region.
  45  * BOOK_LINK_IMAGE      Arrows link to previous/next/exit pages, in addition to the TOC.
  46  * BOOK_LINK_TEXT       Page names and arrows link to previous/next/exit pages, in addition to the TOC.
  47  */
  48 define ('BOOK_LINK_TOCONLY', '0');
  49 define ('BOOK_LINK_IMAGE', '1');
  50 define ('BOOK_LINK_TEXT', '2');
  51
  52 /**
  53  * Preload book chapters and fix toc structure if necessary.
  54  *
  55  * Returns array of chapters with standard 'pagenum', 'id, pagenum, subchapter, title, hidden'
  56  * and extra 'parent, number, subchapters, prev, next'.
  57  * Please note the content/text of chapters is not included.
  58  *
  59  * @param  stdClass $book
  60  * @return array of id=>chapter
  61  */
  62 function book_preload_chapters($book) {
  63     global $DB;
  64     $chapters = $DB->get_records('book_chapters', array('bookid'=>$book->id), 'pagenum', 'id, pagenum, subchapter, title, hidden');
  65     if (!$chapters) {
  66         return array();
  67     }
  68
  69     $prev = null;
  70     $prevsub = null;
  71
  72     $first = true;
  73     $hidesub = true;
  74     $parent = null;
  75     $pagenum = 0; // chapter sort
  76     $i = 0;       // main chapter num
  77     $j = 0;       // subchapter num
  78     foreach ($chapters as $id => $ch) {
  79         $oldch = clone($ch);
  80         $pagenum++;
  81         $ch->pagenum = $pagenum;
  82         if ($first) {
  83             // book can not start with a subchapter
  84             $ch->subchapter = 0;
  85             $first = false;
  86         }
  87         if (!$ch->subchapter) {
  88             if ($ch->hidden) {
  89                 if ($book->numbering == BOOK_NUM_NUMBERS) {
  90                     $ch->number = 'x';
  91                 } else {
  92                     $ch->number = null;
  93                 }
  94             } else {
  95                 $i++;
  96                 $ch->number = $i;
  97             }
  98             $j = 0;
  99             $prevsub = null;
 100             $hidesub = $ch->hidden;
 101             $parent = $ch->id;
 102             $ch->parent = null;
 103             $ch->subchapters = array();
 104         } else {
 105             $ch->parent = $parent;
 106             $ch->subchapters = null;
 107             $chapters[$parent]->subchapters[$ch->id] = $ch->id;
 108             if ($hidesub) {
 109                 // all subchapters in hidden chapter must be hidden too
 110                 $ch->hidden = 1;
 111             }
 112             if ($ch->hidden) {
 113                 if ($book->numbering == BOOK_NUM_NUMBERS) {
 114                     $ch->number = 'x';
 115                 } else {
 116                     $ch->number = null;
 117                 }
 118             } else {
 119                 $j++;
 120                 $ch->number = $j;
 121             }
 122         }
 123
 124         if ($oldch->subchapter != $ch->subchapter or $oldch->pagenum != $ch->pagenum or $oldch->hidden != $ch->hidden) {
 125             // update only if something changed
 126             $DB->update_record('book_chapters', $ch);
 127         }
 128         $chapters[$id] = $ch;
 129     }
 130
 131     return $chapters;
 132 }
 133
 134 /**
 135  * Returns the title for a given chapter
 136  *
 137  * @param int $chid
 138  * @param array $chapters
 139  * @param stdClass $book
 140  * @param context_module $context
 141  * @return string
 142  */
 143 function book_get_chapter_title($chid, $chapters, $book, $context) {
 144     $ch = $chapters[$chid];
 145     $title = trim(format_string($ch->title, true, array('context'=>$context)));
 146     $numbers = array();
 147     if ($book->numbering == BOOK_NUM_NUMBERS) {
 148         if ($ch->parent and $chapters[$ch->parent]->number) {
 149             $numbers[] = $chapters[$ch->parent]->number;
 150         }
 151         if ($ch->number) {
 152             $numbers[] = $ch->number;
 153         }
 154     }
 155
 156     if ($numbers) {
 157         $title = implode('.', $numbers) . '. ' . $title;
 158     }
 159
 160     return $title;
 161 }
 162
 163 /**
 164  * Add the book TOC sticky block to the default region.
 165  *
 166  * @param   array       $chapters   The Chapters in the book
 167  * @param   stdClass    $chapter    The current chapter
 168  * @param   stdClass    $book       The book
 169  * @param   stdClass    $cm         The course module
 170  * @param   bool        $edit       Whether the user is editing
 171  */
 172 function book_add_fake_block($chapters, $chapter, $book, $cm, $edit = null) {
 173     global $PAGE, $USER;
 174
 175     if ($edit === null) {
 176         if (has_capability('mod/book:edit', context_module::instance($cm->id))) {
 177             if (isset($USER->editing)) {
 178                 $edit = $USER->editing;
 179             } else {
 180                 $edit = 0;
 181             }
 182         } else {
 183             $edit = 0;
 184         }
 185     }
 186
 187     $toc = book_get_toc($chapters, $chapter, $book, $cm, $edit, 0);
 188
 189     $bc = new block_contents();
 190     $bc->title = get_string('toc', 'mod_book');
 191     $bc->attributes['class'] = 'block block_book_toc';
 192     $bc->content = $toc;
 193
 194     $defaultregion = $PAGE->blocks->get_default_region();
 195     $PAGE->blocks->add_fake_block($bc, $defaultregion);
 196 }
 197
 198 /**
 199  * Generate toc structure
 200  *
 201  * @param array $chapters
 202  * @param stdClass $chapter
 203  * @param stdClass $book
 204  * @param stdClass $cm
 205  * @param bool $edit
 206  * @return string
 207  */
 208 function book_get_toc($chapters, $chapter, $book, $cm, $edit) {
 209     global $USER, $OUTPUT;
 210
 211     $toc = '';
 212     $nch = 0;   // Chapter number
 213     $ns = 0;    // Subchapter number
 214     $first = 1;
 215
 216     $context = context_module::instance($cm->id);
 217
 218     switch ($book->numbering) {
 219         case BOOK_NUM_NONE:
 220             $toc .= html_writer::start_tag('div', array('class' => 'book_toc_none clearfix'));
 221             break;
 222         case BOOK_NUM_NUMBERS:
 223             $toc .= html_writer::start_tag('div', array('class' => 'book_toc_numbered clearfix'));
 224             break;
 225         case BOOK_NUM_BULLETS:
 226             $toc .= html_writer::start_tag('div', array('class' => 'book_toc_bullets clearfix'));
 227             break;
 228         case BOOK_NUM_INDENTED:
 229             $toc .= html_writer::start_tag('div', array('class' => 'book_toc_indented clearfix'));
 230             break;
 231     }
 232
 233     if ($edit) { // Teacher's TOC
 234         $toc .= html_writer::start_tag('ul');
 235         $i = 0;
 236         foreach ($chapters as $ch) {
 237             $i++;
 238             $title = trim(format_string($ch->title, true, array('context' => $context)));
 239             $titleunescaped = trim(format_string($ch->title, true, array('context' => $context, 'escape' => false)));
 240             $titleout = $title;
 241
 242             if (!$ch->subchapter) {
 243
 244                 if ($first) {
 245                     $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 246                 } else {
 247                     $toc .= html_writer::end_tag('ul');
 248                     $toc .= html_writer::end_tag('li');
 249                     $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 250                 }
 251
 252                 if (!$ch->hidden) {
 253                     $nch++;
 254                     $ns = 0;
 255                     if ($book->numbering == BOOK_NUM_NUMBERS) {
 256                         $title = "$nch. $title";
 257                         $titleout = $title;
 258                     }
 259                 } else {
 260                     if ($book->numbering == BOOK_NUM_NUMBERS) {
 261                         $title = "x. $title";
 262                     }
 263                     $titleout = html_writer::tag('span', $title, array('class' => 'dimmed_text'));
 264                 }
 265             } else {
 266
 267                 if ($first) {
 268                     $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 269                     $toc .= html_writer::start_tag('ul');
 270                     $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 271                 } else {
 272                     $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 273                 }
 274
 275                 if (!$ch->hidden) {
 276                     $ns++;
 277                     if ($book->numbering == BOOK_NUM_NUMBERS) {
 278                         $title = "$nch.$ns. $title";
 279                         $titleout = $title;
 280                     }
 281                 } else {
 282                     if ($book->numbering == BOOK_NUM_NUMBERS) {
 283                         if (empty($chapters[$ch->parent]->hidden)) {
 284                             $title = "$nch.x. $title";
 285                         } else {
 286                             $title = "x.x. $title";
 287                         }
 288                     }
 289                     $titleout = html_writer::tag('span', $title, array('class' => 'dimmed_text'));
 290                 }
 291             }
 292
 293             if ($ch->id == $chapter->id) {
 294                 $toc .= html_writer::tag('strong', $titleout);
 295             } else {
 296                 $toc .= html_writer::link(new moodle_url('view.php', array('id' => $cm->id, 'chapterid' => $ch->id)), $titleout,
 297                     array('title' => $titleunescaped));
 298             }
 299
 300             $toc .= html_writer::start_tag('div', array('class' => 'action-list'));
 301             if ($i != 1) {
 302                 $toc .= html_writer::link(new moodle_url('move.php', array('id' => $cm->id, 'chapterid' => $ch->id, 'up' => '1', 'sesskey' => $USER->sesskey)),
 303                         $OUTPUT->pix_icon('t/up', get_string('movechapterup', 'mod_book', $title)),
 304                         array('title' => get_string('movechapterup', 'mod_book', $titleunescaped)));
 305             }
 306             if ($i != count($chapters)) {
 307                 $toc .= html_writer::link(new moodle_url('move.php', array('id' => $cm->id, 'chapterid' => $ch->id, 'up' => '0', 'sesskey' => $USER->sesskey)),
 308                         $OUTPUT->pix_icon('t/down', get_string('movechapterdown', 'mod_book', $title)),
 309                         array('title' => get_string('movechapterdown', 'mod_book', $titleunescaped)));
 310             }
 311             $toc .= html_writer::link(new moodle_url('edit.php', array('cmid' => $cm->id, 'id' => $ch->id)),
 312                     $OUTPUT->pix_icon('t/edit', get_string('editchapter', 'mod_book', $title)),
 313                     array('title' => get_string('editchapter', 'mod_book', $titleunescaped)));
 314
 315             $deleteaction = new confirm_action(get_string('deletechapter', 'mod_book', $titleunescaped));
 316             $toc .= $OUTPUT->action_icon(
 317                     new moodle_url('delete.php', [
 318                             'id'        => $cm->id,
 319                             'chapterid' => $ch->id,
 320                             'sesskey'   => sesskey(),
 321                             'confirm'   => 1,
 322                         ]),
 323                     new pix_icon('t/delete', get_string('deletechapter', 'mod_book', $title)),
 324                     $deleteaction,
 325                     ['title' => get_string('deletechapter', 'mod_book', $titleunescaped)]
 326                 );
 327
 328             if ($ch->hidden) {
 329                 $toc .= html_writer::link(new moodle_url('show.php', array('id' => $cm->id, 'chapterid' => $ch->id, 'sesskey' => $USER->sesskey)),
 330                         $OUTPUT->pix_icon('t/show', get_string('showchapter', 'mod_book', $title)),
 331                         array('title' => get_string('showchapter', 'mod_book', $titleunescaped)));
 332             } else {
 333                 $toc .= html_writer::link(new moodle_url('show.php', array('id' => $cm->id, 'chapterid' => $ch->id, 'sesskey' => $USER->sesskey)),
 334                         $OUTPUT->pix_icon('t/hide', get_string('hidechapter', 'mod_book', $title)),
 335                         array('title' => get_string('hidechapter', 'mod_book', $titleunescaped)));
 336             }
 337             $toc .= html_writer::link(new moodle_url('edit.php', array('cmid' => $cm->id, 'pagenum' => $ch->pagenum, 'subchapter' => $ch->subchapter)),
 338                                             $OUTPUT->pix_icon('add', get_string('addafter', 'mod_book'), 'mod_book'), array('title' => get_string('addafter', 'mod_book')));
 339             $toc .= html_writer::end_tag('div');
 340
 341             if (!$ch->subchapter) {
 342                 $toc .= html_writer::start_tag('ul');
 343             } else {
 344                 $toc .= html_writer::end_tag('li');
 345             }
 346             $first = 0;
 347         }
 348
 349         $toc .= html_writer::end_tag('ul');
 350         $toc .= html_writer::end_tag('li');
 351         $toc .= html_writer::end_tag('ul');
 352
 353     } else { // Normal students view
 354         $toc .= html_writer::start_tag('ul');
 355         foreach ($chapters as $ch) {
 356             $title = trim(format_string($ch->title, true, array('context'=>$context)));
 357             $titleunescaped = trim(format_string($ch->title, true, array('context' => $context, 'escape' => false)));
 358             if (!$ch->hidden) {
 359                 if (!$ch->subchapter) {
 360                     $nch++;
 361                     $ns = 0;
 362
 363                     if ($first) {
 364                         $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 365                     } else {
 366                         $toc .= html_writer::end_tag('ul');
 367                         $toc .= html_writer::end_tag('li');
 368                         $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 369                     }
 370
 371                     if ($book->numbering == BOOK_NUM_NUMBERS) {
 372                           $title = "$nch. $title";
 373                     }
 374                 } else {
 375                     $ns++;
 376
 377                     if ($first) {
 378                         $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 379                         $toc .= html_writer::start_tag('ul');
 380                         $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 381                     } else {
 382                         $toc .= html_writer::start_tag('li', array('class' => 'clearfix'));
 383                     }
 384
 385                     if ($book->numbering == BOOK_NUM_NUMBERS) {
 386                           $title = "$nch.$ns. $title";
 387                     }
 388                 }
 389                 if ($ch->id == $chapter->id) {
 390                     $toc .= html_writer::tag('strong', $title);
 391                 } else {
 392                     $toc .= html_writer::link(new moodle_url('view.php',
 393                                               array('id' => $cm->id, 'chapterid' => $ch->id)),
 394                                               $title, array('title' => s($titleunescaped)));
 395                 }
 396
 397                 if (!$ch->subchapter) {
 398                     $toc .= html_writer::start_tag('ul');
 399                 } else {
 400                     $toc .= html_writer::end_tag('li');
 401                 }
 402
 403                 $first = 0;
 404             }
 405         }
 406
 407         $toc .= html_writer::end_tag('ul');
 408         $toc .= html_writer::end_tag('li');
 409         $toc .= html_writer::end_tag('ul');
 410
 411     }
 412
 413     $toc .= html_writer::end_tag('div');
 414
 415     $toc = str_replace('<ul></ul>', '', $toc); // Cleanup of invalid structures.
 416
 417     return $toc;
 418 }
 419
 420 /**
 421  * Returns book chapters tagged with a specified tag.
 422  *
 423  * This is a callback used by the tag area mod_book/book_chapters to search for book chapters
 424  * tagged with a specific tag.
 425  *
 426  * @param core_tag_tag $tag
 427  * @param bool $exclusivemode if set to true it means that no other entities tagged with this tag
 428  *             are displayed on the page and the per-page limit may be bigger
 429  * @param int $fromctx context id where the link was displayed, may be used by callbacks
 430  *            to display items in the same context first
 431  * @param int $ctx context id where to search for records
 432  * @param bool $rec search in subcontexts as well
 433  * @param int $page 0-based number of page being displayed
 434  * @return \core_tag\output\tagindex
 435  */
 436 function mod_book_get_tagged_chapters($tag, $exclusivemode = false, $fromctx = 0, $ctx = 0, $rec = true, $page = 0) {
 437     global $OUTPUT;
 438     $perpage = $exclusivemode ? 20 : 5;
 439
 440     // Build the SQL query.
 441     $ctxselect = context_helper::get_preload_record_columns_sql('ctx');
 442     $query = "SELECT bc.id, bc.title, bc.bookid, bc.hidden,
 443                     cm.id AS cmid, c.id AS courseid, c.shortname, c.fullname, $ctxselect
 444                 FROM {book_chapters} bc
 445                 JOIN {book} b ON b.id = bc.bookid
 446                 JOIN {modules} m ON m.name='book'
 447                 JOIN {course_modules} cm ON cm.module = m.id AND cm.instance = b.id
 448                 JOIN {tag_instance} tt ON bc.id = tt.itemid
 449                 JOIN {course} c ON cm.course = c.id
 450                 JOIN {context} ctx ON ctx.instanceid = cm.id AND ctx.contextlevel = :coursemodulecontextlevel
 451                WHERE tt.itemtype = :itemtype AND tt.tagid = :tagid AND tt.component = :component
 452                  AND cm.deletioninprogress = 0
 453                  AND bc.id %ITEMFILTER% AND c.id %COURSEFILTER%";
 454
 455     $params = array('itemtype' => 'book_chapters', 'tagid' => $tag->id, 'component' => 'mod_book',
 456                     'coursemodulecontextlevel' => CONTEXT_MODULE);
 457
 458     if ($ctx) {
 459         $context = $ctx ? context::instance_by_id($ctx) : context_system::instance();
 460         $query .= $rec ? ' AND (ctx.id = :contextid OR ctx.path LIKE :path)' : ' AND ctx.id = :contextid';
 461         $params['contextid'] = $context->id;
 462         $params['path'] = $context->path.'/%';
 463     }
 464
 465     $query .= " ORDER BY ";
 466     if ($fromctx) {
 467         // In order-clause specify that modules from inside "fromctx" context should be returned first.
 468         $fromcontext = context::instance_by_id($fromctx);
 469         $query .= ' (CASE WHEN ctx.id = :fromcontextid OR ctx.path LIKE :frompath THEN 0 ELSE 1 END),';
 470         $params['fromcontextid'] = $fromcontext->id;
 471         $params['frompath'] = $fromcontext->path.'/%';
 472     }
 473     $query .= ' c.sortorder, cm.id, bc.id';
 474
 475     $totalpages = $page + 1;
 476
 477     // Use core_tag_index_builder to build and filter the list of items.
 478     $builder = new core_tag_index_builder('mod_book', 'book_chapters', $query, $params, $page * $perpage, $perpage + 1);
 479     while ($item = $builder->has_item_that_needs_access_check()) {
 480         context_helper::preload_from_record($item);
 481         $courseid = $item->courseid;
 482         if (!$builder->can_access_course($courseid)) {
 483             $builder->set_accessible($item, false);
 484             continue;
 485         }
 486         $modinfo = get_fast_modinfo($builder->get_course($courseid));
 487         // Set accessibility of this item and all other items in the same course.
 488         $builder->walk(function ($taggeditem) use ($courseid, $modinfo, $builder) {
 489             if ($taggeditem->courseid == $courseid) {
 490                 $accessible = false;
 491                 if (($cm = $modinfo->get_cm($taggeditem->cmid)) && $cm->uservisible) {
 492                     if (empty($taggeditem->hidden)) {
 493                         $accessible = true;
 494                     } else {
 495                         $accessible = has_capability('mod/book:viewhiddenchapters', context_module::instance($cm->id));
 496                     }
 497                 }
 498                 $builder->set_accessible($taggeditem, $accessible);
 499             }
 500         });
 501     }
 502
 503     $items = $builder->get_items();
 504     if (count($items) > $perpage) {
 505         $totalpages = $page + 2; // We don't need exact page count, just indicate that the next page exists.
 506         array_pop($items);
 507     }
 508
 509     // Build the display contents.
 510     if ($items) {
 511         $tagfeed = new core_tag\output\tagfeed();
 512         foreach ($items as $item) {
 513             context_helper::preload_from_record($item);
 514             $modinfo = get_fast_modinfo($item->courseid);
 515             $cm = $modinfo->get_cm($item->cmid);
 516             $pageurl = new moodle_url('/mod/book/view.php', array('chapterid' => $item->id, 'b' => $item->bookid));
 517             $pagename = format_string($item->title, true, array('context' => context_module::instance($item->cmid)));
 518             $pagename = html_writer::link($pageurl, $pagename);
 519             $courseurl = course_get_url($item->courseid, $cm->sectionnum);
 520             $cmname = html_writer::link($cm->url, $cm->get_formatted_name());
 521             $coursename = format_string($item->fullname, true, array('context' => context_course::instance($item->courseid)));
 522             $coursename = html_writer::link($courseurl, $coursename);
 523             $icon = html_writer::link($pageurl, html_writer::empty_tag('img', array('src' => $cm->get_icon_url())));
 524             $tagfeed->add($icon, $pagename, $cmname.'<br>'.$coursename);
 525         }
 526
 527         $content = $OUTPUT->render_from_template('core_tag/tagfeed',
 528             $tagfeed->export_for_template($OUTPUT));
 529
 530         return new core_tag\output\tagindex($tag, 'mod_book', 'book_chapters', $content,
 531             $exclusivemode, $fromctx, $ctx, $rec, $page, $totalpages);
 532     }
 533 }
 534
 535 /**
 536  * File browsing support class
 537  *
 538  * @copyright  2010-2011 Petr Skoda {@link http://skodak.org}
 539  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 540  */
 541 class book_file_info extends file_info {
 542     /** @var stdClass Course object */
 543     protected $course;
 544     /** @var stdClass Course module object */
 545     protected $cm;
 546     /** @var array Available file areas */
 547     protected $areas;
 548     /** @var string File area to browse */
 549     protected $filearea;
 550
 551     /**
 552      * Constructor
 553      *
 554      * @param file_browser $browser file_browser instance
 555      * @param stdClass $course course object
 556      * @param stdClass $cm course module object
 557      * @param stdClass $context module context
 558      * @param array $areas available file areas
 559      * @param string $filearea file area to browse
 560      */
 561     public function __construct($browser, $course, $cm, $context, $areas, $filearea) {
 562         parent::__construct($browser, $context);
 563         $this->course   = $course;
 564         $this->cm       = $cm;
 565         $this->areas    = $areas;
 566         $this->filearea = $filearea;
 567     }
 568
 569     /**
 570      * Returns list of standard virtual file/directory identification.
 571      * The difference from stored_file parameters is that null values
 572      * are allowed in all fields
 573      * @return array with keys contextid, filearea, itemid, filepath and filename
 574      */
 575     public function get_params() {
 576         return array('contextid'=>$this->context->id,
 577                      'component'=>'mod_book',
 578                      'filearea' =>$this->filearea,
 579                      'itemid'   =>null,
 580                      'filepath' =>null,
 581                      'filename' =>null);
 582     }
 583
 584     /**
 585      * Returns localised visible name.
 586      * @return string
 587      */
 588     public function get_visible_name() {
 589         return $this->areas[$this->filearea];
 590     }
 591
 592     /**
 593      * Can I add new files or directories?
 594      * @return bool
 595      */
 596     public function is_writable() {
 597         return false;
 598     }
 599
 600     /**
 601      * Is directory?
 602      * @return bool
 603      */
 604     public function is_directory() {
 605         return true;
 606     }
 607
 608     /**
 609      * Returns list of children.
 610      * @return array of file_info instances
 611      */
 612     public function get_children() {
 613         return $this->get_filtered_children('*', false, true);
 614     }
 615
 616     /**
 617      * Help function to return files matching extensions or their count
 618      *
 619      * @param string|array $extensions, either '*' or array of lowercase extensions, i.e. array('.gif','.jpg')
 620      * @param bool|int $countonly if false returns the children, if an int returns just the
 621      *    count of children but stops counting when $countonly number of children is reached
 622      * @param bool $returnemptyfolders if true returns items that don't have matching files inside
 623      * @return array|int array of file_info instances or the count
 624      */
 625     private function get_filtered_children($extensions = '*', $countonly = false, $returnemptyfolders = false) {
 626         global $DB;
 627         $params = array('contextid' => $this->context->id,
 628             'component' => 'mod_book',
 629             'filearea' => $this->filearea,
 630             'bookid' => $this->cm->instance);
 631         $sql = 'SELECT DISTINCT bc.id, bc.pagenum
 632                     FROM {files} f, {book_chapters} bc
 633                     WHERE f.contextid = :contextid
 634                     AND f.component = :component
 635                     AND f.filearea = :filearea
 636                     AND bc.bookid = :bookid
 637                     AND bc.id = f.itemid';
 638         if (!$returnemptyfolders) {
 639             $sql .= ' AND filename <> :emptyfilename';
 640             $params['emptyfilename'] = '.';
 641         }
 642         list($sql2, $params2) = $this->build_search_files_sql($extensions, 'f');
 643         $sql .= ' '.$sql2;
 644         $params = array_merge($params, $params2);
 645         if ($countonly === false) {
 646             $sql .= ' ORDER BY bc.pagenum';
 647         }
 648
 649         $rs = $DB->get_recordset_sql($sql, $params);
 650         $children = array();
 651         foreach ($rs as $record) {
 652             if ($child = $this->browser->get_file_info($this->context, 'mod_book', $this->filearea, $record->id)) {
 653                 if ($returnemptyfolders || $child->count_non_empty_children($extensions)) {
 654                     $children[] = $child;
 655                 }
 656             }
 657             if ($countonly !== false && count($children) >= $countonly) {
 658                 break;
 659             }
 660         }
 661         $rs->close();
 662         if ($countonly !== false) {
 663             return count($children);
 664         }
 665         return $children;
 666     }
 667
 668     /**
 669      * Returns list of children which are either files matching the specified extensions
 670      * or folders that contain at least one such file.
 671      *
 672      * @param string|array $extensions, either '*' or array of lowercase extensions, i.e. array('.gif','.jpg')
 673      * @return array of file_info instances
 674      */
 675     public function get_non_empty_children($extensions = '*') {
 676         return $this->get_filtered_children($extensions, false);
 677     }
 678
 679     /**
 680      * Returns the number of children which are either files matching the specified extensions
 681      * or folders containing at least one such file.
 682      *
 683      * @param string|array $extensions, for example '*' or array('.gif','.jpg')
 684      * @param int $limit stop counting after at least $limit non-empty children are found
 685      * @return int
 686      */
 687     public function count_non_empty_children($extensions = '*', $limit = 1) {
 688         return $this->get_filtered_children($extensions, $limit);
 689     }
 690
 691     /**
 692      * Returns parent file_info instance
 693      * @return file_info or null for root
 694      */
 695     public function get_parent() {
 696         return $this->browser->get_file_info($this->context);
 697     }
 698 }