lib/setuplib.php

   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 /**
  20  * These functions are required very early in the Moodle
  21  * setup process, before any of the main libraries are
  22  * loaded.
  23  *
  24  * @package    core
  25  * @subpackage lib
  26  * @copyright  1999 onwards Martin Dougiamas  {@link http://moodle.com}
  27  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  28  */
  29
  30 defined('MOODLE_INTERNAL') || die();
  31
  32 /// Debug levels ///
  33 /** no warnings at all */
  34 define('DEBUG_NONE', 0);
  35 /** E_ERROR | E_PARSE */
  36 define('DEBUG_MINIMAL', 5);
  37 /** E_ERROR | E_PARSE | E_WARNING | E_NOTICE */
  38 define('DEBUG_NORMAL', 15);
  39 /** E_ALL without E_STRICT for now, do show recoverable fatal errors */
  40 define('DEBUG_ALL', 6143);
  41 /** DEBUG_ALL with extra Moodle debug messages - (DEBUG_ALL | 32768) */
  42 define('DEBUG_DEVELOPER', 38911);
  43
  44 /** Remove any memory limits */
  45 define('MEMORY_UNLIMITED', -1);
  46 /** Standard memory limit for given platform */
  47 define('MEMORY_STANDARD', -2);
  48 /**
  49  * Large memory limit for given platform - used in cron, upgrade, and other places that need a lot of memory.
  50  * Can be overridden with $CFG->extramemorylimit setting.
  51  */
  52 define('MEMORY_EXTRA', -3);
  53 /** Extremely large memory limit - not recommended for standard scripts */
  54 define('MEMORY_HUGE', -4);
  55
  56 /**
  57  * Software maturity levels used by the core and plugins
  58  */
  59 define('MATURITY_ALPHA',    50);    // internals can be tested using white box techniques
  60 define('MATURITY_BETA',     100);   // feature complete, ready for preview and testing
  61 define('MATURITY_RC',       150);   // tested, will be released unless there are fatal bugs
  62 define('MATURITY_STABLE',   200);   // ready for production deployment
  63
  64 /**
  65  * Simple class. It is usually used instead of stdClass because it looks
  66  * more familiar to Java developers ;-) Do not use for type checking of
  67  * function parameters. Please use stdClass instead.
  68  *
  69  * @package    core
  70  * @subpackage lib
  71  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
  72  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  73  * @deprecated since 2.0
  74  */
  75 class object extends stdClass {};
  76
  77 /**
  78  * Base Moodle Exception class
  79  *
  80  * Although this class is defined here, you cannot throw a moodle_exception until
  81  * after moodlelib.php has been included (which will happen very soon).
  82  *
  83  * @package    core
  84  * @subpackage lib
  85  * @copyright  2008 Petr Skoda  {@link http://skodak.org}
  86  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  87  */
  88 class moodle_exception extends Exception {
  89     public $errorcode;
  90     public $module;
  91     public $a;
  92     public $link;
  93     public $debuginfo;
  94
  95     /**
  96      * Constructor
  97      * @param string $errorcode The name of the string from error.php to print
  98      * @param string $module name of module
  99      * @param string $link The url where the user will be prompted to continue. If no url is provided the user will be directed to the site index page.
 100      * @param object $a Extra words and phrases that might be required in the error string
 101      * @param string $debuginfo optional debugging information
 102      */
 103     function __construct($errorcode, $module='', $link='', $a=NULL, $debuginfo=null) {
 104         if (empty($module) || $module == 'moodle' || $module == 'core') {
 105             $module = 'error';
 106         }
 107
 108         $this->errorcode = $errorcode;
 109         $this->module    = $module;
 110         $this->link      = $link;
 111         $this->a         = $a;
 112         $this->debuginfo = $debuginfo;
 113
 114         if (get_string_manager()->string_exists($errorcode, $module)) {
 115             $message = get_string($errorcode, $module, $a);
 116         } else {
 117             $message = $module . '/' . $errorcode;
 118         }
 119
 120         parent::__construct($message, 0);
 121     }
 122 }
 123
 124 /**
 125  * Course/activity access exception.
 126  *
 127  * This exception is thrown from require_login()
 128  *
 129  * @package    core
 130  * @subpackage lib
 131  * @copyright  2010 Petr Skoda  {@link http://skodak.org}
 132  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 133  */
 134 class require_login_exception extends moodle_exception {
 135     function __construct($debuginfo) {
 136         parent::__construct('requireloginerror', 'error', '', NULL, $debuginfo);
 137     }
 138 }
 139
 140 /**
 141  * Web service parameter exception class
 142  * @deprecated since Moodle 2.2 - use moodle exception instead
 143  * This exception must be thrown to the web service client when a web service parameter is invalid
 144  * The error string is gotten from webservice.php
 145  */
 146 class webservice_parameter_exception extends moodle_exception {
 147     /**
 148      * Constructor
 149      * @param string $errorcode The name of the string from webservice.php to print
 150      * @param string $a The name of the parameter
 151      */
 152     function __construct($errorcode=null, $a = '', $debuginfo = null) {
 153         parent::__construct($errorcode, 'webservice', '', $a, $debuginfo);
 154     }
 155 }
 156
 157 /**
 158  * Exceptions indicating user does not have permissions to do something
 159  * and the execution can not continue.
 160  *
 161  * @package    core
 162  * @subpackage lib
 163  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 164  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 165  */
 166 class required_capability_exception extends moodle_exception {
 167     function __construct($context, $capability, $errormessage, $stringfile) {
 168         $capabilityname = get_capability_string($capability);
 169         if ($context->contextlevel == CONTEXT_MODULE and preg_match('/:view$/', $capability)) {
 170             // we can not go to mod/xx/view.php because we most probably do not have cap to view it, let's go to course instead
 171             $paranetcontext = get_context_instance_by_id(get_parent_contextid($context));
 172             $link = get_context_url($paranetcontext);
 173         } else {
 174             $link = get_context_url($context);
 175         }
 176         parent::__construct($errormessage, $stringfile, $link, $capabilityname);
 177     }
 178 }
 179
 180 /**
 181  * Exception indicating programming error, must be fixed by a programer. For example
 182  * a core API might throw this type of exception if a plugin calls it incorrectly.
 183  *
 184  * @package    core
 185  * @subpackage lib
 186  * @copyright  2008 Petr Skoda  {@link http://skodak.org}
 187  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 188  */
 189 class coding_exception extends moodle_exception {
 190     /**
 191      * Constructor
 192      * @param string $hint short description of problem
 193      * @param string $debuginfo detailed information how to fix problem
 194      */
 195     function __construct($hint, $debuginfo=null) {
 196         parent::__construct('codingerror', 'debug', '', $hint, $debuginfo);
 197     }
 198 }
 199
 200 /**
 201  * Exception indicating malformed parameter problem.
 202  * This exception is not supposed to be thrown when processing
 203  * user submitted data in forms. It is more suitable
 204  * for WS and other low level stuff.
 205  *
 206  * @package    core
 207  * @subpackage lib
 208  * @copyright  2009 Petr Skoda  {@link http://skodak.org}
 209  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 210  */
 211 class invalid_parameter_exception extends moodle_exception {
 212     /**
 213      * Constructor
 214      * @param string $debuginfo some detailed information
 215      */
 216     function __construct($debuginfo=null) {
 217         parent::__construct('invalidparameter', 'debug', '', null, $debuginfo);
 218     }
 219 }
 220
 221 /**
 222  * Exception indicating malformed response problem.
 223  * This exception is not supposed to be thrown when processing
 224  * user submitted data in forms. It is more suitable
 225  * for WS and other low level stuff.
 226  */
 227 class invalid_response_exception extends moodle_exception {
 228     /**
 229      * Constructor
 230      * @param string $debuginfo some detailed information
 231      */
 232     function __construct($debuginfo=null) {
 233         parent::__construct('invalidresponse', 'debug', '', null, $debuginfo);
 234     }
 235 }
 236
 237 /**
 238  * An exception that indicates something really weird happened. For example,
 239  * if you do switch ($context->contextlevel), and have one case for each
 240  * CONTEXT_... constant. You might throw an invalid_state_exception in the
 241  * default case, to just in case something really weird is going on, and
 242  * $context->contextlevel is invalid - rather than ignoring this possibility.
 243  *
 244  * @package    core
 245  * @subpackage lib
 246  * @copyright  2009 onwards Martin Dougiamas  {@link http://moodle.com}
 247  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 248  */
 249 class invalid_state_exception extends moodle_exception {
 250     /**
 251      * Constructor
 252      * @param string $hint short description of problem
 253      * @param string $debuginfo optional more detailed information
 254      */
 255     function __construct($hint, $debuginfo=null) {
 256         parent::__construct('invalidstatedetected', 'debug', '', $hint, $debuginfo);
 257     }
 258 }
 259
 260 /**
 261  * An exception that indicates incorrect permissions in $CFG->dataroot
 262  *
 263  * @package    core
 264  * @subpackage lib
 265  * @copyright  2010 Petr Skoda {@link http://skodak.org}
 266  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 267  */
 268 class invalid_dataroot_permissions extends moodle_exception {
 269     /**
 270      * Constructor
 271      * @param string $debuginfo optional more detailed information
 272      */
 273     function __construct($debuginfo = NULL) {
 274         parent::__construct('invaliddatarootpermissions', 'error', '', NULL, $debuginfo);
 275     }
 276 }
 277
 278 /**
 279  * An exception that indicates that file can not be served
 280  *
 281  * @package    core
 282  * @subpackage lib
 283  * @copyright  2010 Petr Skoda {@link http://skodak.org}
 284  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 285  */
 286 class file_serving_exception extends moodle_exception {
 287     /**
 288      * Constructor
 289      * @param string $debuginfo optional more detailed information
 290      */
 291     function __construct($debuginfo = NULL) {
 292         parent::__construct('cannotservefile', 'error', '', NULL, $debuginfo);
 293     }
 294 }
 295
 296 /**
 297  * Default exception handler, uncaught exceptions are equivalent to error() in 1.9 and earlier
 298  *
 299  * @param Exception $ex
 300  * @return void -does not return. Terminates execution!
 301  */
 302 function default_exception_handler($ex) {
 303     global $CFG, $DB, $OUTPUT, $USER, $FULLME, $SESSION;
 304
 305     // detect active db transactions, rollback and log as error
 306     abort_all_db_transactions();
 307
 308     if (($ex instanceof required_capability_exception) && !CLI_SCRIPT && !AJAX_SCRIPT && !empty($CFG->autologinguests) && !empty($USER->autologinguest)) {
 309         $SESSION->wantsurl = $FULLME;
 310         redirect(get_login_url());
 311     }
 312
 313     $info = get_exception_info($ex);
 314
 315     if (debugging('', DEBUG_MINIMAL)) {
 316         $logerrmsg = "Default exception handler: ".$info->message.' Debug: '.$info->debuginfo."\n".format_backtrace($info->backtrace, true);
 317         error_log($logerrmsg);
 318     }
 319
 320     if (is_early_init($info->backtrace)) {
 321         echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 322     } else {
 323         try {
 324             if ($DB) {
 325                 // If you enable db debugging and exception is thrown, the print footer prints a lot of rubbish
 326                 $DB->set_debug(0);
 327             }
 328             echo $OUTPUT->fatal_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 329         } catch (Exception $out_ex) {
 330             // default exception handler MUST not throw any exceptions!!
 331             // the problem here is we do not know if page already started or not, we only know that somebody messed up in outputlib or theme
 332             // so we just print at least something instead of "Exception thrown without a stack frame in Unknown on line 0":-(
 333             if (CLI_SCRIPT or AJAX_SCRIPT) {
 334                 // just ignore the error and send something back using the safest method
 335                 echo bootstrap_renderer::early_error($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 336             } else {
 337                 echo bootstrap_renderer::early_error_content($info->message, $info->moreinfourl, $info->link, $info->backtrace, $info->debuginfo);
 338                 $outinfo = get_exception_info($out_ex);
 339                 echo bootstrap_renderer::early_error_content($outinfo->message, $outinfo->moreinfourl, $outinfo->link, $outinfo->backtrace, $outinfo->debuginfo);
 340             }
 341         }
 342     }
 343
 344     exit(1); // General error code
 345 }
 346
 347 /**
 348  * Default error handler, prevents some white screens.
 349  * @param int $errno
 350  * @param string $errstr
 351  * @param string $errfile
 352  * @param int $errline
 353  * @param array $errcontext
 354  * @return bool false means use default error handler
 355  */
 356 function default_error_handler($errno, $errstr, $errfile, $errline, $errcontext) {
 357     if ($errno == 4096) {
 358         //fatal catchable error
 359         throw new coding_exception('PHP catchable fatal error', $errstr);
 360     }
 361     return false;
 362 }
 363
 364 /**
 365  * Unconditionally abort all database transactions, this function
 366  * should be called from exception handlers only.
 367  * @return void
 368  */
 369 function abort_all_db_transactions() {
 370     global $CFG, $DB, $SCRIPT;
 371
 372     // default exception handler MUST not throw any exceptions!!
 373
 374     if ($DB && $DB->is_transaction_started()) {
 375         error_log('Database transaction aborted automatically in ' . $CFG->dirroot . $SCRIPT);
 376         // note: transaction blocks should never change current $_SESSION
 377         $DB->force_transaction_rollback();
 378     }
 379 }
 380
 381 /**
 382  * This function encapsulates the tests for whether an exception was thrown in
 383  * early init -- either during setup.php or during init of $OUTPUT.
 384  *
 385  * If another exception is thrown then, and if we do not take special measures,
 386  * we would just get a very cryptic message "Exception thrown without a stack
 387  * frame in Unknown on line 0". That makes debugging very hard, so we do take
 388  * special measures in default_exception_handler, with the help of this function.
 389  *
 390  * @param array $backtrace the stack trace to analyse.
 391  * @return boolean whether the stack trace is somewhere in output initialisation.
 392  */
 393 function is_early_init($backtrace) {
 394     $dangerouscode = array(
 395         array('function' => 'header', 'type' => '->'),
 396         array('class' => 'bootstrap_renderer'),
 397         array('file' => dirname(__FILE__).'/setup.php'),
 398     );
 399     foreach ($backtrace as $stackframe) {
 400         foreach ($dangerouscode as $pattern) {
 401             $matches = true;
 402             foreach ($pattern as $property => $value) {
 403                 if (!isset($stackframe[$property]) || $stackframe[$property] != $value) {
 404                     $matches = false;
 405                 }
 406             }
 407             if ($matches) {
 408                 return true;
 409             }
 410         }
 411     }
 412     return false;
 413 }
 414
 415 /**
 416  * Abort execution by throwing of a general exception,
 417  * default exception handler displays the error message in most cases.
 418  *
 419  * @param string $errorcode The name of the language string containing the error message.
 420  *      Normally this should be in the error.php lang file.
 421  * @param string $module The language file to get the error message from.
 422  * @param string $link The url where the user will be prompted to continue.
 423  *      If no url is provided the user will be directed to the site index page.
 424  * @param object $a Extra words and phrases that might be required in the error string
 425  * @param string $debuginfo optional debugging information
 426  * @return void, always throws exception!
 427  */
 428 function print_error($errorcode, $module = 'error', $link = '', $a = null, $debuginfo = null) {
 429     throw new moodle_exception($errorcode, $module, $link, $a, $debuginfo);
 430 }
 431
 432 /**
 433  * Returns detailed information about specified exception.
 434  * @param exception $ex
 435  * @return object
 436  */
 437 function get_exception_info($ex) {
 438     global $CFG, $DB, $SESSION;
 439
 440     if ($ex instanceof moodle_exception) {
 441         $errorcode = $ex->errorcode;
 442         $module = $ex->module;
 443         $a = $ex->a;
 444         $link = $ex->link;
 445         $debuginfo = $ex->debuginfo;
 446     } else {
 447         $errorcode = 'generalexceptionmessage';
 448         $module = 'error';
 449         $a = $ex->getMessage();
 450         $link = '';
 451         $debuginfo = null;
 452     }
 453
 454     $backtrace = $ex->getTrace();
 455     $place = array('file'=>$ex->getFile(), 'line'=>$ex->getLine(), 'exception'=>get_class($ex));
 456     array_unshift($backtrace, $place);
 457
 458     // Be careful, no guarantee moodlelib.php is loaded.
 459     if (empty($module) || $module == 'moodle' || $module == 'core') {
 460         $module = 'error';
 461     }
 462     if (function_exists('get_string_manager')) {
 463         if (get_string_manager()->string_exists($errorcode, $module)) {
 464             $message = get_string($errorcode, $module, $a);
 465         } elseif ($module == 'error' && get_string_manager()->string_exists($errorcode, 'moodle')) {
 466             // Search in moodle file if error specified - needed for backwards compatibility
 467             $message = get_string($errorcode, 'moodle', $a);
 468         } else {
 469             $message = $module . '/' . $errorcode;
 470         }
 471     } else {
 472         $message = $module . '/' . $errorcode;
 473     }
 474
 475     // Be careful, no guarantee weblib.php is loaded.
 476     if (function_exists('clean_text')) {
 477         $message = clean_text($message);
 478     } else {
 479         $message = htmlspecialchars($message);
 480     }
 481
 482     if (!empty($CFG->errordocroot)) {
 483         $errordoclink = $CFG->errordocroot . '/en/';
 484     } else {
 485         $errordoclink = get_docs_url();
 486     }
 487
 488     if ($module === 'error') {
 489         $modulelink = 'moodle';
 490     } else {
 491         $modulelink = $module;
 492     }
 493     $moreinfourl = $errordoclink . 'error/' . $modulelink . '/' . $errorcode;
 494
 495     if (empty($link)) {
 496         if (!empty($SESSION->fromurl)) {
 497             $link = $SESSION->fromurl;
 498             unset($SESSION->fromurl);
 499         } else {
 500             $link = $CFG->wwwroot .'/';
 501         }
 502     }
 503
 504     // when printing an error the continue button should never link offsite
 505     if (stripos($link, $CFG->wwwroot) === false &&
 506         stripos($link, $CFG->httpswwwroot) === false) {
 507         $link = $CFG->wwwroot.'/';
 508     }
 509
 510     $info = new stdClass();
 511     $info->message     = $message;
 512     $info->errorcode   = $errorcode;
 513     $info->backtrace   = $backtrace;
 514     $info->link        = $link;
 515     $info->moreinfourl = $moreinfourl;
 516     $info->a           = $a;
 517     $info->debuginfo   = $debuginfo;
 518
 519     return $info;
 520 }
 521
 522 /**
 523  * Returns the Moodle Docs URL in the users language
 524  *
 525  * @global object
 526  * @param string $path the end of the URL.
 527  * @return string The MoodleDocs URL in the user's language. for example {@link http://docs.moodle.org/en/ http://docs.moodle.org/en/$path}
 528  */
 529 function get_docs_url($path=null) {
 530     global $CFG;
 531     // Check that $CFG->release has been set up, during installation it won't be.
 532     if (empty($CFG->release)) {
 533         // It's not there yet so look at version.php
 534         include($CFG->dirroot.'/version.php');
 535     } else {
 536         // We can use $CFG->release and avoid having to include version.php
 537         $release = $CFG->release;
 538     }
 539     // Attempt to match the branch from the release
 540     if (preg_match('/^(.)\.(.)/', $release, $matches)) {
 541         // We should ALWAYS get here
 542         $branch = $matches[1].$matches[2];
 543     } else {
 544         // We should never get here but in case we do lets set $branch to .
 545         // the smart one's will know that this is the current directory
 546         // and the smarter ones will know that there is some smart matching
 547         // that will ensure people end up at the latest version of the docs.
 548         $branch = '.';
 549     }
 550     if (!empty($CFG->docroot)) {
 551         return $CFG->docroot . '/' . $branch . '/' . current_language() . '/' . $path;
 552     } else {
 553         return 'http://docs.moodle.org/'. $branch . '/en/' . $path;
 554     }
 555 }
 556
 557 /**
 558  * Formats a backtrace ready for output.
 559  *
 560  * @param array $callers backtrace array, as returned by debug_backtrace().
 561  * @param boolean $plaintext if false, generates HTML, if true generates plain text.
 562  * @return string formatted backtrace, ready for output.
 563  */
 564 function format_backtrace($callers, $plaintext = false) {
 565     // do not use $CFG->dirroot because it might not be available in destructors
 566     $dirroot = dirname(dirname(__FILE__));
 567
 568     if (empty($callers)) {
 569         return '';
 570     }
 571
 572     $from = $plaintext ? '' : '<ul style="text-align: left">';
 573     foreach ($callers as $caller) {
 574         if (!isset($caller['line'])) {
 575             $caller['line'] = '?'; // probably call_user_func()
 576         }
 577         if (!isset($caller['file'])) {
 578             $caller['file'] = 'unknownfile'; // probably call_user_func()
 579         }
 580         $from .= $plaintext ? '* ' : '<li>';
 581         $from .= 'line ' . $caller['line'] . ' of ' . str_replace($dirroot, '', $caller['file']);
 582         if (isset($caller['function'])) {
 583             $from .= ': call to ';
 584             if (isset($caller['class'])) {
 585                 $from .= $caller['class'] . $caller['type'];
 586             }
 587             $from .= $caller['function'] . '()';
 588         } else if (isset($caller['exception'])) {
 589             $from .= ': '.$caller['exception'].' thrown';
 590         }
 591         $from .= $plaintext ? "\n" : '</li>';
 592     }
 593     $from .= $plaintext ? '' : '</ul>';
 594
 595     return $from;
 596 }
 597
 598 /**
 599  * This function makes the return value of ini_get consistent if you are
 600  * setting server directives through the .htaccess file in apache.
 601  *
 602  * Current behavior for value set from php.ini On = 1, Off = [blank]
 603  * Current behavior for value set from .htaccess On = On, Off = Off
 604  * Contributed by jdell @ unr.edu
 605  *
 606  * @param string $ini_get_arg The argument to get
 607  * @return bool True for on false for not
 608  */
 609 function ini_get_bool($ini_get_arg) {
 610     $temp = ini_get($ini_get_arg);
 611
 612     if ($temp == '1' or strtolower($temp) == 'on') {
 613         return true;
 614     }
 615     return false;
 616 }
 617
 618 /**
 619  * This function verifies the sanity of PHP configuration
 620  * and stops execution if anything critical found.
 621  */
 622 function setup_validate_php_configuration() {
 623    // this must be very fast - no slow checks here!!!
 624
 625    if (ini_get_bool('register_globals')) {
 626        print_error('globalswarning', 'admin');
 627    }
 628    if (ini_get_bool('session.auto_start')) {
 629        print_error('sessionautostartwarning', 'admin');
 630    }
 631    if (ini_get_bool('magic_quotes_runtime')) {
 632        print_error('fatalmagicquotesruntime', 'admin');
 633    }
 634 }
 635
 636 /**
 637  * Initialise global $CFG variable
 638  * @return void
 639  */
 640 function initialise_cfg() {
 641     global $CFG, $DB;
 642
 643     try {
 644         if ($DB) {
 645             $localcfg = $DB->get_records_menu('config', array(), '', 'name,value');
 646             foreach ($localcfg as $name=>$value) {
 647                 if (property_exists($CFG, $name)) {
 648                     // config.php settings always take precedence
 649                     continue;
 650                 }
 651                 $CFG->{$name} = $value;
 652             }
 653         }
 654     } catch (dml_read_exception $e) {
 655         // most probably empty db, going to install soon
 656     }
 657 }
 658
 659 /**
 660  * Initialises $FULLME and friends. Private function. Should only be called from
 661  * setup.php.
 662  */
 663 function initialise_fullme() {
 664     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 665
 666     // Detect common config error.
 667     if (substr($CFG->wwwroot, -1) == '/') {
 668         print_error('wwwrootslash', 'error');
 669     }
 670
 671     if (CLI_SCRIPT) {
 672         initialise_fullme_cli();
 673         return;
 674     }
 675
 676     $rurl = setup_get_remote_url();
 677     $wwwroot = parse_url($CFG->wwwroot.'/');
 678
 679     if (empty($rurl['host'])) {
 680         // missing host in request header, probably not a real browser, let's ignore them
 681
 682     } else if (!empty($CFG->reverseproxy)) {
 683         // $CFG->reverseproxy specifies if reverse proxy server used
 684         // Used in load balancing scenarios.
 685         // Do not abuse this to try to solve lan/wan access problems!!!!!
 686
 687     } else {
 688         if (($rurl['host'] !== $wwwroot['host']) or (!empty($wwwroot['port']) and $rurl['port'] != $wwwroot['port'])) {
 689             // Explain the problem and redirect them to the right URL
 690             if (!defined('NO_MOODLE_COOKIES')) {
 691                 define('NO_MOODLE_COOKIES', true);
 692             }
 693             redirect($CFG->wwwroot, get_string('wwwrootmismatch', 'error', $CFG->wwwroot), 3);
 694         }
 695     }
 696
 697     // Check that URL is under $CFG->wwwroot.
 698     if (strpos($rurl['path'], $wwwroot['path']) === 0) {
 699         $SCRIPT = substr($rurl['path'], strlen($wwwroot['path'])-1);
 700     } else {
 701         // Probably some weird external script
 702         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 703         return;
 704     }
 705
 706     // $CFG->sslproxy specifies if external SSL appliance is used
 707     // (That is, the Moodle server uses http, with an external box translating everything to https).
 708     if (empty($CFG->sslproxy)) {
 709         if ($rurl['scheme'] === 'http' and $wwwroot['scheme'] === 'https') {
 710             print_error('sslonlyaccess', 'error');
 711         }
 712     } else {
 713         if ($wwwroot['scheme'] !== 'https') {
 714             throw new coding_exception('Must use https address in wwwroot when ssl proxy enabled!');
 715         }
 716         $rurl['scheme'] = 'https'; // make moodle believe it runs on https, squid or something else it doing it
 717     }
 718
 719     // hopefully this will stop all those "clever" admins trying to set up moodle
 720     // with two different addresses in intranet and Internet
 721     if (!empty($CFG->reverseproxy) && $rurl['host'] === $wwwroot['host']) {
 722         print_error('reverseproxyabused', 'error');
 723     }
 724
 725     $hostandport = $rurl['scheme'] . '://' . $wwwroot['host'];
 726     if (!empty($wwwroot['port'])) {
 727         $hostandport .= ':'.$wwwroot['port'];
 728     }
 729
 730     $FULLSCRIPT = $hostandport . $rurl['path'];
 731     $FULLME = $hostandport . $rurl['fullpath'];
 732     $ME = $rurl['fullpath'];
 733 }
 734
 735 /**
 736  * Initialises $FULLME and friends for command line scripts.
 737  * This is a private method for use by initialise_fullme.
 738  */
 739 function initialise_fullme_cli() {
 740     global $CFG, $FULLME, $ME, $SCRIPT, $FULLSCRIPT;
 741
 742     // Urls do not make much sense in CLI scripts
 743     $backtrace = debug_backtrace();
 744     $topfile = array_pop($backtrace);
 745     $topfile = realpath($topfile['file']);
 746     $dirroot = realpath($CFG->dirroot);
 747
 748     if (strpos($topfile, $dirroot) !== 0) {
 749         // Probably some weird external script
 750         $SCRIPT = $FULLSCRIPT = $FULLME = $ME = null;
 751     } else {
 752         $relativefile = substr($topfile, strlen($dirroot));
 753         $relativefile = str_replace('\\', '/', $relativefile); // Win fix
 754         $SCRIPT = $FULLSCRIPT = $relativefile;
 755         $FULLME = $ME = null;
 756     }
 757 }
 758
 759 /**
 760  * Get the URL that PHP/the web server thinks it is serving. Private function
 761  * used by initialise_fullme. In your code, use $PAGE->url, $SCRIPT, etc.
 762  * @return array in the same format that parse_url returns, with the addition of
 763  *      a 'fullpath' element, which includes any slasharguments path.
 764  */
 765 function setup_get_remote_url() {
 766     $rurl = array();
 767     if (isset($_SERVER['HTTP_HOST'])) {
 768         list($rurl['host']) = explode(':', $_SERVER['HTTP_HOST']);
 769     } else {
 770         $rurl['host'] = null;
 771     }
 772     $rurl['port'] = $_SERVER['SERVER_PORT'];
 773     $rurl['path'] = $_SERVER['SCRIPT_NAME']; // Script path without slash arguments
 774     $rurl['scheme'] = (empty($_SERVER['HTTPS']) or $_SERVER['HTTPS'] === 'off' or $_SERVER['HTTPS'] === 'Off' or $_SERVER['HTTPS'] === 'OFF') ? 'http' : 'https';
 775
 776     if (stripos($_SERVER['SERVER_SOFTWARE'], 'apache') !== false) {
 777         //Apache server
 778         $rurl['fullpath'] = $_SERVER['REQUEST_URI'];
 779
 780     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
 781         //IIS - needs a lot of tweaking to make it work
 782         $rurl['fullpath'] = $_SERVER['SCRIPT_NAME'];
 783
 784         // NOTE: ignore PATH_INFO because it is incorrectly encoded using 8bit filesystem legacy encoding in IIS
 785         //       since 2.0 we rely on iis rewrite extenssion like Helicon ISAPI_rewrite
 786         //       example rule: RewriteRule ^([^\?]+?\.php)(\/.+)$ $1\?file=$2 [QSA]
 787
 788         if ($_SERVER['QUERY_STRING'] != '') {
 789             $rurl['fullpath'] .= '?'.$_SERVER['QUERY_STRING'];
 790         }
 791         $_SERVER['REQUEST_URI'] = $rurl['fullpath']; // extra IIS compatibility
 792
 793 /* NOTE: following servers are not fully tested! */
 794
 795     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'lighttpd') !== false) {
 796         //lighttpd - not officially supported
 797         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 798
 799     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'nginx') !== false) {
 800         //nginx - not officially supported
 801         if (!isset($_SERVER['SCRIPT_NAME'])) {
 802             die('Invalid server configuration detected, please try to add "fastcgi_param SCRIPT_NAME $fastcgi_script_name;" to the nginx server configuration.');
 803         }
 804         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 805
 806      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'cherokee') !== false) {
 807          //cherokee - not officially supported
 808          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 809
 810      } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'zeus') !== false) {
 811          //zeus - not officially supported
 812          $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 813
 814     } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'LiteSpeed') !== false) {
 815         //LiteSpeed - not officially supported
 816         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 817
 818     } else if ($_SERVER['SERVER_SOFTWARE'] === 'HTTPD') {
 819         //obscure name found on some servers - this is definitely not supported
 820         $rurl['fullpath'] = $_SERVER['REQUEST_URI']; // TODO: verify this is always properly encoded
 821
 822      } else {
 823         throw new moodle_exception('unsupportedwebserver', 'error', '', $_SERVER['SERVER_SOFTWARE']);
 824     }
 825
 826     // sanitize the url a bit more, the encoding style may be different in vars above
 827     $rurl['fullpath'] = str_replace('"', '%22', $rurl['fullpath']);
 828     $rurl['fullpath'] = str_replace('\'', '%27', $rurl['fullpath']);
 829
 830     return $rurl;
 831 }
 832
 833 /**
 834  * Initializes our performance info early.
 835  *
 836  * Pairs up with get_performance_info() which is actually
 837  * in moodlelib.php. This function is here so that we can
 838  * call it before all the libs are pulled in.
 839  *
 840  * @uses $PERF
 841  */
 842 function init_performance_info() {
 843
 844     global $PERF, $CFG, $USER;
 845
 846     $PERF = new stdClass();
 847     $PERF->logwrites = 0;
 848     if (function_exists('microtime')) {
 849         $PERF->starttime = microtime();
 850     }
 851     if (function_exists('memory_get_usage')) {
 852         $PERF->startmemory = memory_get_usage();
 853     }
 854     if (function_exists('posix_times')) {
 855         $PERF->startposixtimes = posix_times();
 856     }
 857 }
 858
 859 /**
 860  * Indicates whether we are in the middle of the initial Moodle install.
 861  *
 862  * Very occasionally it is necessary avoid running certain bits of code before the
 863  * Moodle installation has completed. The installed flag is set in admin/index.php
 864  * after Moodle core and all the plugins have been installed, but just before
 865  * the person doing the initial install is asked to choose the admin password.
 866  *
 867  * @return boolean true if the initial install is not complete.
 868  */
 869 function during_initial_install() {
 870     global $CFG;
 871     return empty($CFG->rolesactive);
 872 }
 873
 874 /**
 875  * Function to raise the memory limit to a new value.
 876  * Will respect the memory limit if it is higher, thus allowing
 877  * settings in php.ini, apache conf or command line switches
 878  * to override it.
 879  *
 880  * The memory limit should be expressed with a constant
 881  * MEMORY_STANDARD, MEMORY_EXTRA or MEMORY_HUGE.
 882  * It is possible to use strings or integers too (eg:'128M').
 883  *
 884  * @param mixed $newlimit the new memory limit
 885  * @return bool success
 886  */
 887 function raise_memory_limit($newlimit) {
 888     global $CFG;
 889
 890     if ($newlimit == MEMORY_UNLIMITED) {
 891         ini_set('memory_limit', -1);
 892         return true;
 893
 894     } else if ($newlimit == MEMORY_STANDARD) {
 895         if (PHP_INT_SIZE > 4) {
 896             $newlimit = get_real_size('128M'); // 64bit needs more memory
 897         } else {
 898             $newlimit = get_real_size('96M');
 899         }
 900
 901     } else if ($newlimit == MEMORY_EXTRA) {
 902         if (PHP_INT_SIZE > 4) {
 903             $newlimit = get_real_size('384M'); // 64bit needs more memory
 904         } else {
 905             $newlimit = get_real_size('256M');
 906         }
 907         if (!empty($CFG->extramemorylimit)) {
 908             $extra = get_real_size($CFG->extramemorylimit);
 909             if ($extra > $newlimit) {
 910                 $newlimit = $extra;
 911             }
 912         }
 913
 914     } else if ($newlimit == MEMORY_HUGE) {
 915         $newlimit = get_real_size('2G');
 916
 917     } else {
 918         $newlimit = get_real_size($newlimit);
 919     }
 920
 921     if ($newlimit <= 0) {
 922         debugging('Invalid memory limit specified.');
 923         return false;
 924     }
 925
 926     $cur = ini_get('memory_limit');
 927     if (empty($cur)) {
 928         // if php is compiled without --enable-memory-limits
 929         // apparently memory_limit is set to ''
 930         $cur = 0;
 931     } else {
 932         if ($cur == -1){
 933             return true; // unlimited mem!
 934         }
 935         $cur = get_real_size($cur);
 936     }
 937
 938     if ($newlimit > $cur) {
 939         ini_set('memory_limit', $newlimit);
 940         return true;
 941     }
 942     return false;
 943 }
 944
 945 /**
 946  * Function to reduce the memory limit to a new value.
 947  * Will respect the memory limit if it is lower, thus allowing
 948  * settings in php.ini, apache conf or command line switches
 949  * to override it
 950  *
 951  * The memory limit should be expressed with a string (eg:'64M')
 952  *
 953  * @param string $newlimit the new memory limit
 954  * @return bool
 955  */
 956 function reduce_memory_limit($newlimit) {
 957     if (empty($newlimit)) {
 958         return false;
 959     }
 960     $cur = ini_get('memory_limit');
 961     if (empty($cur)) {
 962         // if php is compiled without --enable-memory-limits
 963         // apparently memory_limit is set to ''
 964         $cur = 0;
 965     } else {
 966         if ($cur == -1){
 967             return true; // unlimited mem!
 968         }
 969         $cur = get_real_size($cur);
 970     }
 971
 972     $new = get_real_size($newlimit);
 973     // -1 is smaller, but it means unlimited
 974     if ($new < $cur && $new != -1) {
 975         ini_set('memory_limit', $newlimit);
 976         return true;
 977     }
 978     return false;
 979 }
 980
 981 /**
 982  * Converts numbers like 10M into bytes.
 983  *
 984  * @param string $size The size to be converted
 985  * @return int
 986  */
 987 function get_real_size($size = 0) {
 988     if (!$size) {
 989         return 0;
 990     }
 991     $scan = array();
 992     $scan['GB'] = 1073741824;
 993     $scan['Gb'] = 1073741824;
 994     $scan['G'] = 1073741824;
 995     $scan['MB'] = 1048576;
 996     $scan['Mb'] = 1048576;
 997     $scan['M'] = 1048576;
 998     $scan['m'] = 1048576;
 999     $scan['KB'] = 1024;
1000     $scan['Kb'] = 1024;
1001     $scan['K'] = 1024;
1002     $scan['k'] = 1024;
1003
1004     while (list($key) = each($scan)) {
1005         if ((strlen($size)>strlen($key))&&(substr($size, strlen($size) - strlen($key))==$key)) {
1006             $size = substr($size, 0, strlen($size) - strlen($key)) * $scan[$key];
1007             break;
1008         }
1009     }
1010     return $size;
1011 }
1012
1013 /**
1014  * Try to disable all output buffering and purge
1015  * all headers.
1016  *
1017  * @private to be called only from lib/setup.php !
1018  * @return void
1019  */
1020 function disable_output_buffering() {
1021     $olddebug = error_reporting(0);
1022
1023     // disable compression, it would prevent closing of buffers
1024     if (ini_get_bool('zlib.output_compression')) {
1025         ini_set('zlib.output_compression', 'Off');
1026     }
1027
1028     // try to flush everything all the time
1029     ob_implicit_flush(true);
1030
1031     // close all buffers if possible and discard any existing output
1032     // this can actually work around some whitespace problems in config.php
1033     while(ob_get_level()) {
1034         if (!ob_end_clean()) {
1035             // prevent infinite loop when buffer can not be closed
1036             break;
1037         }
1038     }
1039
1040     error_reporting($olddebug);
1041 }
1042
1043 /**
1044  * Check whether a major upgrade is needed. That is defined as an upgrade that
1045  * changes something really fundamental in the database, so nothing can possibly
1046  * work until the database has been updated, and that is defined by the hard-coded
1047  * version number in this function.
1048  */
1049 function redirect_if_major_upgrade_required() {
1050     global $CFG;
1051     $lastmajordbchanges = 2010111700;
1052     if (empty($CFG->version) or (int)$CFG->version < $lastmajordbchanges or
1053             during_initial_install() or !empty($CFG->adminsetuppending)) {
1054         try {
1055             @session_get_instance()->terminate_current();
1056         } catch (Exception $e) {
1057             // Ignore any errors, redirect to upgrade anyway.
1058         }
1059         $url = $CFG->wwwroot . '/' . $CFG->admin . '/index.php';
1060         @header($_SERVER['SERVER_PROTOCOL'] . ' 303 See Other');
1061         @header('Location: ' . $url);
1062         echo bootstrap_renderer::plain_redirect_message(htmlspecialchars($url));
1063         exit;
1064     }
1065 }
1066
1067 /**
1068  * Function to check if a directory exists and by default create it if not exists.
1069  *
1070  * Previously this was accepting paths only from dataroot, but we now allow
1071  * files outside of dataroot if you supply custom paths for some settings in config.php.
1072  * This function does not verify that the directory is writable.
1073  *
1074  * @param string $dir absolute directory path
1075  * @param boolean $create directory if does not exist
1076  * @param boolean $recursive create directory recursively
1077  * @return boolean true if directory exists or created, false otherwise
1078  */
1079 function check_dir_exists($dir, $create = true, $recursive = true) {
1080     global $CFG;
1081
1082     umask(0000); // just in case some evil code changed it
1083
1084     if (is_dir($dir)) {
1085         return true;
1086     }
1087
1088     if (!$create) {
1089         return false;
1090     }
1091
1092     return mkdir($dir, $CFG->directorypermissions, $recursive);
1093 }
1094
1095 /**
1096  * Create a directory and make sure it is writable.
1097  *
1098  * @private
1099  * @param string $dir  the full path of the directory to be created
1100  * @param bool $exceptiononerror throw exception if error encountered
1101  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1102  */
1103 function make_writable_directory($dir, $exceptiononerror = true) {
1104     global $CFG;
1105
1106     if (file_exists($dir) and !is_dir($dir)) {
1107         if ($exceptiononerror) {
1108             throw new coding_exception($dir.' directory can not be created, file with the same name already exists.');
1109         } else {
1110             return false;
1111         }
1112     }
1113
1114     umask(0000); // just in case some evil code changed it
1115
1116     if (!file_exists($dir)) {
1117         if (!mkdir($dir, $CFG->directorypermissions, true)) {
1118             if ($exceptiononerror) {
1119                 throw new invalid_dataroot_permissions($dir.' can not be created, check permissions.');
1120             } else {
1121                 return false;
1122             }
1123         }
1124     }
1125
1126     if (!is_writable($dir)) {
1127         if ($exceptiononerror) {
1128             throw new invalid_dataroot_permissions($dir.' is not writable, check permissions.');
1129         } else {
1130             return false;
1131         }
1132     }
1133
1134     return $dir;
1135 }
1136
1137 /**
1138  * Protect a directory from web access.
1139  * Could be extended in the future to support other mechanisms (e.g. other webservers).
1140  *
1141  * @private
1142  * @param string $dir  the full path of the directory to be protected
1143  */
1144 function protect_directory($dir) {
1145     // Make sure a .htaccess file is here, JUST IN CASE the files area is in the open and .htaccess is supported
1146     if (!file_exists("$dir/.htaccess")) {
1147         if ($handle = fopen("$dir/.htaccess", 'w')) {   // For safety
1148             @fwrite($handle, "deny from all\r\nAllowOverride None\r\nNote: this file is broken intentionally, we do not want anybody to undo it in subdirectory!\r\n");
1149             @fclose($handle);
1150         }
1151     }
1152 }
1153
1154 /**
1155  * Create a directory under dataroot and make sure it is writable.
1156  * Do not use for temporary and cache files - see make_temp_directory() and make_cache_directory().
1157  *
1158  * @param string $directory  the full path of the directory to be created under $CFG->dataroot
1159  * @param bool $exceptiononerror throw exception if error encountered
1160  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1161  */
1162 function make_upload_directory($directory, $exceptiononerror = true) {
1163     global $CFG;
1164
1165     if (strpos($directory, 'temp/') === 0 or $directory === 'temp') {
1166         debugging('Use make_temp_directory() for creation of temporary directory and $CFG->tempdir to get the location.');
1167
1168     } else if (strpos($directory, 'cache/') === 0 or $directory === 'cache') {
1169         debugging('Use make_cache_directory() for creation of chache directory and $CFG->cachedir to get the location.');
1170     }
1171
1172     protect_directory($CFG->dataroot);
1173     return make_writable_directory("$CFG->dataroot/$directory", $exceptiononerror);
1174 }
1175
1176 /**
1177  * Create a directory under tempdir and make sure it is writable.
1178  * Temporary files should be used during the current request only!
1179  *
1180  * @param string $directory  the full path of the directory to be created under $CFG->tempdir
1181  * @param bool $exceptiononerror throw exception if error encountered
1182  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1183  */
1184 function make_temp_directory($directory, $exceptiononerror = true) {
1185     global $CFG;
1186     protect_directory($CFG->tempdir);
1187     return make_writable_directory("$CFG->tempdir/$directory", $exceptiononerror);
1188 }
1189
1190 /**
1191  * Create a directory under cachedir and make sure it is writable.
1192  *
1193  * @param string $directory  the full path of the directory to be created under $CFG->cachedir
1194  * @param bool $exceptiononerror throw exception if error encountered
1195  * @return string|false Returns full path to directory if successful, false if not; may throw exception
1196  */
1197 function make_cache_directory($directory, $exceptiononerror = true) {
1198     global $CFG;
1199     protect_directory($CFG->cachedir);
1200     return make_writable_directory("$CFG->cachedir/$directory", $exceptiononerror);
1201 }
1202
1203
1204 function init_memcached() {
1205     global $CFG, $MCACHE;
1206
1207     include_once($CFG->libdir . '/memcached.class.php');
1208     $MCACHE = new memcached;
1209     if ($MCACHE->status()) {
1210         return true;
1211     }
1212     unset($MCACHE);
1213     return false;
1214 }
1215
1216 function init_eaccelerator() {
1217     global $CFG, $MCACHE;
1218
1219     include_once($CFG->libdir . '/eaccelerator.class.php');
1220     $MCACHE = new eaccelerator;
1221     if ($MCACHE->status()) {
1222         return true;
1223     }
1224     unset($MCACHE);
1225     return false;
1226 }
1227
1228 /**
1229  * Checks if current user is a web crawler.
1230  *
1231  * This list can not be made complete, this is not a security
1232  * restriction, we make the list only to help these sites
1233  * especially when automatic guest login is disabled.
1234  *
1235  * If admin needs security they should enable forcelogin
1236  * and disable guest access!!
1237  *
1238  * @return bool
1239  */
1240 function is_web_crawler() {
1241     if (!empty($_SERVER['HTTP_USER_AGENT'])) {
1242         if (strpos($_SERVER['HTTP_USER_AGENT'], 'Googlebot') !== false ) {
1243             return true;
1244         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'google.com') !== false ) { // Google
1245             return true;
1246         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yahoo! Slurp') !== false ) {  // Yahoo
1247             return true;
1248         } else if (strpos($_SERVER['HTTP_USER_AGENT'], '[ZSEBOT]') !== false ) {  // Zoomspider
1249             return true;
1250         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSNBOT') !== false ) {  // MSN Search
1251             return true;
1252         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'Yandex') !== false ) {
1253             return true;
1254         } else if (strpos($_SERVER['HTTP_USER_AGENT'], 'AltaVista') !== false ) {
1255             return true;
1256         }
1257     }
1258     return false;
1259 }
1260
1261 /**
1262  * This class solves the problem of how to initialise $OUTPUT.
1263  *
1264  * The problem is caused be two factors
1265  * <ol>
1266  * <li>On the one hand, we cannot be sure when output will start. In particular,
1267  * an error, which needs to be displayed, could be thrown at any time.</li>
1268  * <li>On the other hand, we cannot be sure when we will have all the information
1269  * necessary to correctly initialise $OUTPUT. $OUTPUT depends on the theme, which
1270  * (potentially) depends on the current course, course categories, and logged in user.
1271  * It also depends on whether the current page requires HTTPS.</li>
1272  * </ol>
1273  *
1274  * So, it is hard to find a single natural place during Moodle script execution,
1275  * which we can guarantee is the right time to initialise $OUTPUT. Instead we
1276  * adopt the following strategy
1277  * <ol>
1278  * <li>We will initialise $OUTPUT the first time it is used.</li>
1279  * <li>If, after $OUTPUT has been initialised, the script tries to change something
1280  * that $OUTPUT depends on, we throw an exception making it clear that the script
1281  * did something wrong.
1282  * </ol>
1283  *
1284  * The only problem with that is, how do we initialise $OUTPUT on first use if,
1285  * it is going to be used like $OUTPUT->somthing(...)? Well that is where this
1286  * class comes in. Initially, we set up $OUTPUT = new bootstrap_renderer(). Then,
1287  * when any method is called on that object, we initialise $OUTPUT, and pass the call on.
1288  *
1289  * Note that this class is used before lib/outputlib.php has been loaded, so we
1290  * must be careful referring to classes/functions from there, they may not be
1291  * defined yet, and we must avoid fatal errors.
1292  *
1293  * @copyright 2009 Tim Hunt
1294  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1295  * @since     Moodle 2.0
1296  */
1297 class bootstrap_renderer {
1298     /**
1299      * Handles re-entrancy. Without this, errors or debugging output that occur
1300      * during the initialisation of $OUTPUT, cause infinite recursion.
1301      * @var boolean
1302      */
1303     protected $initialising = false;
1304
1305     /**
1306      * Have we started output yet?
1307      * @return boolean true if the header has been printed.
1308      */
1309     public function has_started() {
1310         return false;
1311     }
1312
1313     /**
1314      * Constructor - to be used by core code only.
1315      * @param $method
1316      * @param $arguments
1317      * @return string
1318      */
1319     public function __call($method, $arguments) {
1320         global $OUTPUT, $PAGE;
1321
1322         $recursing = false;
1323         if ($method == 'notification') {
1324             // Catch infinite recursion caused by debugging output during print_header.
1325             $backtrace = debug_backtrace();
1326             array_shift($backtrace);
1327             array_shift($backtrace);
1328             $recursing = is_early_init($backtrace);
1329         }
1330
1331         $earlymethods = array(
1332             'fatal_error' => 'early_error',
1333             'notification' => 'early_notification',
1334         );
1335
1336         // If lib/outputlib.php has been loaded, call it.
1337         if (!empty($PAGE) && !$recursing) {
1338             if (array_key_exists($method, $earlymethods)) {
1339                 //prevent PAGE->context warnings - exceptions might appear before we set any context
1340                 $PAGE->set_context(null);
1341             }
1342             $PAGE->initialise_theme_and_output();
1343             return call_user_func_array(array($OUTPUT, $method), $arguments);
1344         }
1345
1346         $this->initialising = true;
1347
1348         // Too soon to initialise $OUTPUT, provide a couple of key methods.
1349         if (array_key_exists($method, $earlymethods)) {
1350             return call_user_func_array(array('bootstrap_renderer', $earlymethods[$method]), $arguments);
1351         }
1352
1353         throw new coding_exception('Attempt to start output before enough information is known to initialise the theme.');
1354     }
1355
1356     /**
1357      * Returns nicely formatted error message in a div box.
1358      * @static
1359      * @param string $message error message
1360      * @param string $moreinfourl (ignored in early errors)
1361      * @param string $link (ignored in early errors)
1362      * @param array $backtrace
1363      * @param string $debuginfo
1364      * @return string
1365      */
1366     public static function early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1367         global $CFG;
1368
1369         $content = '<div style="margin-top: 6em; margin-left:auto; margin-right:auto; color:#990000; text-align:center; font-size:large; border-width:1px;
1370 border-color:black; background-color:#ffffee; border-style:solid; border-radius: 20px; border-collapse: collapse;
1371 width: 80%; -moz-border-radius: 20px; padding: 15px">
1372 ' . $message . '
1373 </div>';
1374         if (!empty($CFG->debug) && $CFG->debug >= DEBUG_DEVELOPER) {
1375             if (!empty($debuginfo)) {
1376                 $debuginfo = s($debuginfo); // removes all nasty JS
1377                 $debuginfo = str_replace("\n", '<br />', $debuginfo); // keep newlines
1378                 $content .= '<div class="notifytiny">Debug info: ' . $debuginfo . '</div>';
1379             }
1380             if (!empty($backtrace)) {
1381                 $content .= '<div class="notifytiny">Stack trace: ' . format_backtrace($backtrace, false) . '</div>';
1382             }
1383         }
1384
1385         return $content;
1386     }
1387
1388     /**
1389      * This function should only be called by this class, or from exception handlers
1390      * @static
1391      * @param string $message error message
1392      * @param string $moreinfourl (ignored in early errors)
1393      * @param string $link (ignored in early errors)
1394      * @param array $backtrace
1395      * @param string $debuginfo extra information for developers
1396      * @return string
1397      */
1398     public static function early_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
1399         global $CFG;
1400
1401         if (CLI_SCRIPT) {
1402             echo "!!! $message !!!\n";
1403             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1404                 if (!empty($debuginfo)) {
1405                     echo "\nDebug info: $debuginfo";
1406                 }
1407                 if (!empty($backtrace)) {
1408                     echo "\nStack trace: " . format_backtrace($backtrace, true);
1409                 }
1410             }
1411             return;
1412
1413         } else if (AJAX_SCRIPT) {
1414             $e = new stdClass();
1415             $e->error      = $message;
1416             $e->stacktrace = NULL;
1417             $e->debuginfo  = NULL;
1418             if (!empty($CFG->debug) and $CFG->debug >= DEBUG_DEVELOPER) {
1419                 if (!empty($debuginfo)) {
1420                     $e->debuginfo = $debuginfo;
1421                 }
1422                 if (!empty($backtrace)) {
1423                     $e->stacktrace = format_backtrace($backtrace, true);
1424                 }
1425             }
1426             @header('Content-Type: application/json; charset=utf-8');
1427             echo json_encode($e);
1428             return;
1429         }
1430
1431         // In the name of protocol correctness, monitoring and performance
1432         // profiling, set the appropriate error headers for machine consumption
1433         if (isset($_SERVER['SERVER_PROTOCOL'])) {
1434             // Avoid it with cron.php. Note that we assume it's HTTP/1.x
1435             // The 503 ode here means our Moodle does not work at all, the error happened too early
1436             @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
1437         }
1438
1439         // better disable any caching
1440         @header('Content-Type: text/html; charset=utf-8');
1441         @header('Cache-Control: no-store, no-cache, must-revalidate');
1442         @header('Cache-Control: post-check=0, pre-check=0', false);
1443         @header('Pragma: no-cache');
1444         @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
1445         @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
1446
1447         if (function_exists('get_string')) {
1448             $strerror = get_string('error');
1449         } else {
1450             $strerror = 'Error';
1451         }
1452
1453         $content = self::early_error_content($message, $moreinfourl, $link, $backtrace, $debuginfo);
1454
1455         return self::plain_page($strerror, $content);
1456     }
1457
1458     /**
1459      * Early notification message
1460      * @static
1461      * @param $message
1462      * @param string $classes usually notifyproblem or notifysuccess
1463      * @return string
1464      */
1465     public static function early_notification($message, $classes = 'notifyproblem') {
1466         return '<div class="' . $classes . '">' . $message . '</div>';
1467     }
1468
1469     /**
1470      * Page should redirect message.
1471      * @static
1472      * @param $encodedurl redirect url
1473      * @return string
1474      */
1475     public static function plain_redirect_message($encodedurl) {
1476         $message = '<div style="margin-top: 3em; margin-left:auto; margin-right:auto; text-align:center;">' . get_string('pageshouldredirect') . '<br /><a href="'.
1477                 $encodedurl .'">'. get_string('continue') .'</a></div>';
1478         return self::plain_page(get_string('redirect'), $message);
1479     }
1480
1481     /**
1482      * Early redirection page, used before full init of $PAGE global
1483      * @static
1484      * @param $encodedurl redirect url
1485      * @param $message redirect message
1486      * @param $delay time in seconds
1487      * @return string redirect page
1488      */
1489     public static function early_redirect_message($encodedurl, $message, $delay) {
1490         $meta = '<meta http-equiv="refresh" content="'. $delay .'; url='. $encodedurl .'" />';
1491         $content = self::early_error_content($message, null, null, null);
1492         $content .= self::plain_redirect_message($encodedurl);
1493
1494         return self::plain_page(get_string('redirect'), $content, $meta);
1495     }
1496
1497     /**
1498      * Output basic html page.
1499      * @static
1500      * @param $title page title
1501      * @param $content page content
1502      * @param string $meta meta tag
1503      * @return string html page
1504      */
1505     protected static function plain_page($title, $content, $meta = '') {
1506         if (function_exists('get_string') && function_exists('get_html_lang')) {
1507             $htmllang = get_html_lang();
1508         } else {
1509             $htmllang = '';
1510         }
1511
1512         return '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
1513 <html xmlns="http://www.w3.org/1999/xhtml" ' . $htmllang . '>
1514 <head>
1515 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
1516 '.$meta.'
1517 <title>' . $title . '</title>
1518 </head><body>' . $content . '</body></html>';
1519     }
1520 }