lib/classes/progress/display.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 namespace core\progress;
  18
  19 defined('MOODLE_INTERNAL') || die();
  20
  21 /**
  22  * Progress handler that uses a standard Moodle progress bar to display
  23  * progress. The Moodle progress bar cannot show indeterminate progress,
  24  * so we do extra output in addition to the bar.
  25  *
  26  * @package core_progress
  27  * @copyright 2013 The Open University
  28  * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  29  */
  30 class display extends base {
  31     /**
  32      * @var int Number of wibble states (state0...stateN-1 classes in CSS)
  33      */
  34     const WIBBLE_STATES = 13;
  35
  36     /**
  37      * @var \progress_bar Current progress bar.
  38      */
  39     private $bar;
  40
  41     protected $lastwibble, $currentstate = 0, $direction = 1;
  42
  43     /**
  44      * @var bool True to display names
  45      */
  46     protected $displaynames = false;
  47
  48     /**
  49      * Constructs the progress reporter. This will output HTML code for the
  50      * progress bar, and an indeterminate wibbler below it.
  51      *
  52      * @param bool $startnow If true, outputs HTML immediately.
  53      */
  54     public function __construct($startnow = true) {
  55         if ($startnow) {
  56             $this->start_html();
  57         }
  58     }
  59
  60     /**
  61      * By default, the progress section names do not display because
  62      * these will probably be untranslated and incomprehensible. To make them
  63      * display, call this method.
  64      *
  65      * @param bool $displaynames True to display names
  66      */
  67     public function set_display_names($displaynames = true) {
  68         $this->displaynames = $displaynames;
  69     }
  70
  71     /**
  72      * Starts to output progress.
  73      *
  74      * Called in constructor and in update_progress if required.
  75      *
  76      * @throws \coding_exception If already started
  77      */
  78     public function start_html() {
  79         if ($this->bar) {
  80             throw new \coding_exception('Already started');
  81         }
  82         $this->bar = new \progress_bar();
  83         $this->bar->create();
  84         echo \html_writer::start_div('wibbler');
  85     }
  86
  87     /**
  88      * Finishes output. (Progress can begin again later if there are more
  89      * calls to update_progress.)
  90      *
  91      * Automatically called from update_progress when progress finishes.
  92      */
  93     public function end_html() {
  94         // Finish progress bar.
  95         $this->bar->update_full(100, '');
  96         $this->bar = null;
  97
  98         // End wibbler div.
  99         echo \html_writer::end_div();
 100     }
 101
 102     /**
 103      * When progress is updated, updates the bar.
 104      *
 105      * @see \core\progress\base::update_progress()
 106      */
 107     public function update_progress() {
 108         // If finished...
 109         if (!$this->is_in_progress_section()) {
 110             if ($this->bar) {
 111                 $this->end_html();
 112             }
 113         } else {
 114             if (!$this->bar) {
 115                 $this->start_html();
 116             }
 117             // In case of indeterminate or small progress, update the wibbler
 118             // (up to once per second).
 119             if (time() != $this->lastwibble) {
 120                 $this->lastwibble = time();
 121                 echo \html_writer::div('', 'wibble state' . $this->currentstate);
 122
 123                 // Go on to next colour.
 124                 $this->currentstate += $this->direction;
 125                 if ($this->currentstate < 0 || $this->currentstate >= self::WIBBLE_STATES) {
 126                     $this->direction = -$this->direction;
 127                     $this->currentstate += 2 * $this->direction;
 128                 }
 129                 $buffersize = ini_get('output_buffering');
 130                 if (!is_numeric($buffersize)) {
 131                     // The output_buffering setting can be a number, but can also be "On" or "Off".
 132                     // If "Off", there's no buffer, if "On", there's no limit to the size. In either case,
 133                     // there's no point in trying to fill the buffer.
 134                     $buffersize = 0;
 135                 }
 136                 if ($buffersize) {
 137                     // Force the buffer full.
 138                     echo str_pad('', $buffersize);
 139                 }
 140             }
 141
 142             // Get progress.
 143             list ($min, $max) = $this->get_progress_proportion_range();
 144
 145             // Update progress bar.
 146             $message = '';
 147             if ($this->displaynames) {
 148                 $message = $this->get_current_description();
 149             }
 150             $this->bar->update_full($min * 100, $message);
 151
 152             // Flush output.
 153             flush();
 154         }
 155     }
 156 }