if ($forum->type == 'qanda' && !has_capability('mod/forum:viewqandawithoutposting', $modcontext) && !empty($discussion->id) && !forum_user_has_posted($forum->id, $discussion->id, $USER->id)) {
    echo $OUTPUT->notification(get_string('qandanotify', 'forum'));
}
forum_check_throttling($forum, $cm);
if (!empty($parent)) {
    if (!($discussion = $DB->get_record('forum_discussions', array('id' => $parent->discussion)))) {
        print_error('notpartofdiscussion', 'forum');
    }
    // #marginalia begin
    $moodlemia = moodle_marginalia::get_instance();
    $miaprofile = $moodlemia->get_profile($PAGE->url->out(false));
    if ($miaprofile) {
        $miaprofile->emit_body();
        $miaprofile->emit_margin_controls();
    }
    // #marginalia end
    forum_print_post($parent, $discussion, $forum, $cm, $course, false, false, false);
    if (empty($post->edit)) {
        if ($forum->type != 'qanda' || forum_user_can_see_discussion($forum, $discussion, $modcontext)) {
            $forumtracked = forum_tp_is_tracked($forum);
            $posts = forum_get_all_discussion_posts($discussion->id, "created ASC", $forumtracked);
            forum_print_posts_threaded($course, $cm, $forum, $discussion, $parent, 0, false, $forumtracked, $posts);
        }
    }
} else {
    if (!empty($forum->intro)) {
        echo $OUTPUT->box(format_module_intro('forum', $forum, $cm->id), 'generalbox', 'intro');
    }
}
$mform_post->display();
echo $OUTPUT->footer();

/**
 * Prints a forum discussion
 *
 * @uses CONTEXT_MODULE
 * @uses FORUM_MODE_FLATNEWEST
 * @uses FORUM_MODE_FLATOLDEST
 * @uses FORUM_MODE_THREADED
 * @uses FORUM_MODE_NESTED
 * @param stdClass $course
 * @param stdClass $cm
 * @param stdClass $forum
 * @param stdClass $discussion
 * @param stdClass $post
 * @param int $mode
 * @param mixed $canreply
 * @param bool $canrate
 */
function forum_print_discussion($course, $cm, $forum, $discussion, $post, $mode, $canreply=NULL, $canrate=false) {
    global $USER, $CFG;

    require_once($CFG->dirroot.'/rating/lib.php');

    $ownpost = (isloggedin() && $USER->id == $post->userid);

    $modcontext = context_module::instance($cm->id);
    if ($canreply === NULL) {
        $reply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);
    } else {
        $reply = $canreply;
    }

    // $cm holds general cache for forum functions
    $cm->cache = new stdClass;
    $cm->cache->groups      = groups_get_all_groups($course->id, 0, $cm->groupingid);
    $cm->cache->usersgroups = array();

    $posters = array();

    // preload all posts - TODO: improve...
    if ($mode == FORUM_MODE_FLATNEWEST) {
        $sort = "p.created DESC";
    } else {
        $sort = "p.created ASC";
    }

    $forumtracked = forum_tp_is_tracked($forum);
    $posts = forum_get_all_discussion_posts($discussion->id, $sort, $forumtracked);
    $post = $posts[$post->id];

    foreach ($posts as $pid=>$p) {
        $posters[$p->userid] = $p->userid;
    }

    // preload all groups of ppl that posted in this discussion
    if ($postersgroups = groups_get_all_groups($course->id, $posters, $cm->groupingid, 'gm.id, gm.groupid, gm.userid')) {
        foreach($postersgroups as $pg) {
            if (!isset($cm->cache->usersgroups[$pg->userid])) {
                $cm->cache->usersgroups[$pg->userid] = array();
            }
            $cm->cache->usersgroups[$pg->userid][$pg->groupid] = $pg->groupid;
        }
        unset($postersgroups);
    }

    //load ratings
    if ($forum->assessed != RATING_AGGREGATE_NONE) {
        $ratingoptions = new stdClass;
        $ratingoptions->context = $modcontext;
        $ratingoptions->component = 'mod_forum';
        $ratingoptions->ratingarea = 'post';
        $ratingoptions->items = $posts;
        $ratingoptions->aggregate = $forum->assessed;//the aggregation method
        $ratingoptions->scaleid = $forum->scale;
        $ratingoptions->userid = $USER->id;
        if ($forum->type == 'single' or !$discussion->id) {
            $ratingoptions->returnurl = "$CFG->wwwroot/mod/forum/view.php?id=$cm->id";
        } else {
            $ratingoptions->returnurl = "$CFG->wwwroot/mod/forum/discuss.php?d=$discussion->id";
        }
        $ratingoptions->assesstimestart = $forum->assesstimestart;
        $ratingoptions->assesstimefinish = $forum->assesstimefinish;

        $rm = new rating_manager();
        $posts = $rm->get_ratings($ratingoptions);
    }


    $post->forum = $forum->id;   // Add the forum id to the post object, later used by forum_print_post
    $post->forumtype = $forum->type;

    $post->subject = format_string($post->subject);

    $postread = !empty($post->postread);

    forum_print_post($post, $discussion, $forum, $cm, $course, $ownpost, $reply, false,
                         '', '', $postread, true, $forumtracked);

    switch ($mode) {
        case FORUM_MODE_FLATOLDEST :
        case FORUM_MODE_FLATNEWEST :
//.........这里部分代码省略.........

 /**
  * @global object
  */
 public function load_data()
 {
     global $DB;
     if ($this->postid) {
         if (!($this->post = $DB->get_record('forum_posts', array('id' => $this->postid)))) {
             throw new portfolio_caller_exception('invalidpostid', 'forum');
         }
     }
     $dparams = array();
     if ($this->discussionid) {
         $dbparams = array('id' => $this->discussionid);
     } else {
         if ($this->post) {
             $dbparams = array('id' => $this->post->discussion);
         } else {
             throw new portfolio_caller_exception('mustprovidediscussionorpost', 'forum');
         }
     }
     if (!($this->discussion = $DB->get_record('forum_discussions', $dbparams))) {
         throw new portfolio_caller_exception('invaliddiscussionid', 'forum');
     }
     if (!($this->forum = $DB->get_record('forum', array('id' => $this->discussion->forum)))) {
         throw new portfolio_caller_exception('invalidforumid', 'forum');
     }
     if (!($this->cm = get_coursemodule_from_instance('forum', $this->forum->id))) {
         throw new portfolio_caller_exception('invalidcoursemodule');
     }
     $this->modcontext = get_context_instance(CONTEXT_MODULE, $this->cm->id);
     $fs = get_file_storage();
     if ($this->post) {
         if ($this->attachment) {
             $this->set_file_and_format_data($this->attachment);
         } else {
             $attach = $fs->get_area_files($this->modcontext->id, 'mod_forum', 'attachment', $this->post->id, 'timemodified', false);
             $embed = $fs->get_area_files($this->modcontext->id, 'mod_forum', 'post', $this->post->id, 'timemodified', false);
             $files = array_merge($attach, $embed);
             $this->set_file_and_format_data($files);
         }
         if (!empty($this->multifiles)) {
             $this->keyedfiles[$this->post->id] = $this->multifiles;
         } else {
             if (!empty($this->singlefile)) {
                 $this->keyedfiles[$this->post->id] = array($this->singlefile);
             }
         }
     } else {
         // whole thread
         $fs = get_file_storage();
         $this->posts = forum_get_all_discussion_posts($this->discussion->id, 'p.created ASC');
         $this->multifiles = array();
         foreach ($this->posts as $post) {
             $attach = $fs->get_area_files($this->modcontext->id, 'mod_forum', 'attachment', $post->id, 'timemodified', false);
             $embed = $fs->get_area_files($this->modcontext->id, 'mod_forum', 'post', $post->id, 'timemodified', false);
             $files = array_merge($attach, $embed);
             if ($files) {
                 $this->keyedfiles[$post->id] = $files;
             } else {
                 continue;
             }
             $this->multifiles = array_merge($this->multifiles, array_values($this->keyedfiles[$post->id]));
         }
     }
     if (empty($this->multifiles) && !empty($this->singlefile)) {
         $this->multifiles = array($this->singlefile);
         // copy_files workaround
     }
     // depending on whether there are files or not, we might have to change richhtml/plainhtml
     if (empty($this->attachment)) {
         if (!empty($this->multifiles)) {
             $this->add_format(PORTFOLIO_FORMAT_RICHHTML);
         } else {
             $this->add_format(PORTFOLIO_FORMAT_PLAINHTML);
         }
     }
 }

 /**
  * Returns a list of forum posts for a discussion
  *
  * @param int $discussionid the post ids
  * @param string $sortby sort by this element (id, created or modified)
  * @param string $sortdirection sort direction: ASC or DESC
  *
  * @return array the forum post details
  * @since Moodle 2.7
  */
 public static function get_forum_discussion_posts($discussionid, $sortby = "created", $sortdirection = "DESC")
 {
     global $CFG, $DB, $USER;
     $warnings = array();
     // Validate the parameter.
     $params = self::validate_parameters(self::get_forum_discussion_posts_parameters(), array('discussionid' => $discussionid, 'sortby' => $sortby, 'sortdirection' => $sortdirection));
     // Compact/extract functions are not recommended.
     $discussionid = $params['discussionid'];
     $sortby = $params['sortby'];
     $sortdirection = $params['sortdirection'];
     $sortallowedvalues = array('id', 'created', 'modified');
     if (!in_array($sortby, $sortallowedvalues)) {
         throw new invalid_parameter_exception('Invalid value for sortby parameter (value: ' . $sortby . '),' . 'allowed values are: ' . implode(',', $sortallowedvalues));
     }
     $sortdirection = strtoupper($sortdirection);
     $directionallowedvalues = array('ASC', 'DESC');
     if (!in_array($sortdirection, $directionallowedvalues)) {
         throw new invalid_parameter_exception('Invalid value for sortdirection parameter (value: ' . $sortdirection . '),' . 'allowed values are: ' . implode(',', $directionallowedvalues));
     }
     $discussion = $DB->get_record('forum_discussions', array('id' => $discussionid), '*', MUST_EXIST);
     $forum = $DB->get_record('forum', array('id' => $discussion->forum), '*', MUST_EXIST);
     $course = $DB->get_record('course', array('id' => $forum->course), '*', MUST_EXIST);
     $cm = get_coursemodule_from_instance('forum', $forum->id, $course->id, false, MUST_EXIST);
     // Validate the module context. It checks everything that affects the module visibility (including groupings, etc..).
     $modcontext = context_module::instance($cm->id);
     self::validate_context($modcontext);
     // This require must be here, see mod/forum/discuss.php.
     require_once $CFG->dirroot . "/mod/forum/lib.php";
     // Check they have the view forum capability.
     require_capability('mod/forum:viewdiscussion', $modcontext, null, true, 'noviewdiscussionspermission', 'forum');
     if (!($post = forum_get_post_full($discussion->firstpost))) {
         throw new moodle_exception('notexists', 'forum');
     }
     // This function check groups, qanda, timed discussions, etc.
     if (!forum_user_can_see_post($forum, $discussion, $post, null, $cm)) {
         throw new moodle_exception('noviewdiscussionspermission', 'forum');
     }
     $canviewfullname = has_capability('moodle/site:viewfullnames', $modcontext);
     // We will add this field in the response.
     $canreply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);
     $forumtracked = forum_tp_is_tracked($forum);
     $sort = 'p.' . $sortby . ' ' . $sortdirection;
     $posts = forum_get_all_discussion_posts($discussion->id, $sort, $forumtracked);
     foreach ($posts as $pid => $post) {
         if (!forum_user_can_see_post($forum, $discussion, $post, null, $cm)) {
             $warning = array();
             $warning['item'] = 'post';
             $warning['itemid'] = $post->id;
             $warning['warningcode'] = '1';
             $warning['message'] = 'You can\'t see this post';
             $warnings[] = $warning;
             continue;
         }
         // Function forum_get_all_discussion_posts adds postread field.
         // Note that the value returned can be a boolean or an integer. The WS expects a boolean.
         if (empty($post->postread)) {
             $posts[$pid]->postread = false;
         } else {
             $posts[$pid]->postread = true;
         }
         $posts[$pid]->canreply = $canreply;
         if (!empty($posts[$pid]->children)) {
             $posts[$pid]->children = array_keys($posts[$pid]->children);
         } else {
             $posts[$pid]->children = array();
         }
         $user = new stdclass();
         $user = username_load_fields_from_object($user, $post);
         $posts[$pid]->userfullname = fullname($user, $canviewfullname);
         $posts[$pid] = (array) $post;
     }
     $result = array();
     $result['posts'] = $posts;
     $result['warnings'] = $warnings;
     return $result;
 }

 function get_news_item($id)
 {
     global $CFG, $DB;
     $posts = forum_get_all_discussion_posts($id, 'created');
     $item_posts = array();
     foreach ($posts as $post) {
         $p['subject'] = $post->subject;
         $p['message'] = $post->message;
         $item_posts[] = $p;
     }
     return $item_posts;
 }

/**
 *
 */
function forum_print_discussion($course, $cm, $forum, $discussion, $post, $mode, $canreply = NULL, $canrate = false)
{
    global $USER, $CFG;
    if (!empty($USER->id)) {
        $ownpost = $USER->id == $post->userid;
    } else {
        $ownpost = false;
    }
    if ($canreply === NULL) {
        $modcontext = get_context_instance(CONTEXT_MODULE, $cm->id);
        $reply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);
    } else {
        $reply = $canreply;
    }
    // $cm holds general cache for forum functions
    $cm->cache = new object();
    $cm->cache->groups = groups_get_all_groups($course->id, 0, $cm->groupingid);
    $cm->cache->usersgroups = array();
    $posters = array();
    // preload all posts - TODO: improve...
    if ($mode == FORUM_MODE_FLATNEWEST) {
        $sort = "p.created DESC";
    } else {
        $sort = "p.created ASC";
    }
    $forumtracked = forum_tp_is_tracked($forum);
    $posts = forum_get_all_discussion_posts($discussion->id, $sort, $forumtracked);
    $post = $posts[$post->id];
    foreach ($posts as $pid => $p) {
        $posters[$p->userid] = $p->userid;
    }
    // preload all groups of ppl that posted in this discussion
    if ($postersgroups = groups_get_all_groups($course->id, $posters, $cm->groupingid, 'gm.id, gm.groupid, gm.userid')) {
        foreach ($postersgroups as $pg) {
            if (!isset($cm->cache->usersgroups[$pg->userid])) {
                $cm->cache->usersgroups[$pg->userid] = array();
            }
            $cm->cache->usersgroups[$pg->userid][$pg->groupid] = $pg->groupid;
        }
        unset($postersgroups);
    }
    $ratings = NULL;
    $ratingsmenuused = false;
    $ratingsformused = false;
    if ($forum->assessed and isloggedin()) {
        if ($ratings->scale = make_grades_menu($forum->scale)) {
            $ratings->assesstimestart = $forum->assesstimestart;
            $ratings->assesstimefinish = $forum->assesstimefinish;
            $ratings->allow = $canrate;
            if ($ratings->allow) {
                echo '<form id="form" method="post" action="rate.php">';
                echo '<div class="ratingform">';
                echo '<input type="hidden" name="forumid" value="' . $forum->id . '" />';
                $ratingsformused = true;
            }
            // preload all ratings - one query only and minimal memory
            $cm->cache->ratings = array();
            $cm->cache->myratings = array();
            if ($postratings = forum_get_all_discussion_ratings($discussion)) {
                foreach ($postratings as $pr) {
                    if (!isset($cm->cache->ratings[$pr->postid])) {
                        $cm->cache->ratings[$pr->postid] = array();
                    }
                    $cm->cache->ratings[$pr->postid][$pr->id] = $pr->rating;
                    if ($pr->userid == $USER->id) {
                        $cm->cache->myratings[$pr->postid] = $pr->rating;
                    }
                }
                unset($postratings);
            }
        }
    }
    $post->forum = $forum->id;
    // Add the forum id to the post object, later used by forum_print_post
    $post->forumtype = $forum->type;
    $post->subject = format_string($post->subject);
    $postread = !empty($post->postread);
    if (forum_print_post($post, $discussion, $forum, $cm, $course, $ownpost, $reply, false, $ratings, '', '', $postread, true, $forumtracked)) {
        $ratingsmenuused = true;
    }
    switch ($mode) {
        case FORUM_MODE_FLATOLDEST:
        case FORUM_MODE_FLATNEWEST:
        default:
            if (forum_print_posts_flat($course, $cm, $forum, $discussion, $post, $mode, $ratings, $reply, $forumtracked, $posts)) {
                $ratingsmenuused = true;
            }
            break;
        case FORUM_MODE_THREADED:
            if (forum_print_posts_threaded($course, $cm, $forum, $discussion, $post, 0, $ratings, $reply, $forumtracked, $posts)) {
                $ratingsmenuused = true;
            }
            break;
        case FORUM_MODE_NESTED:
            if (forum_print_posts_nested($course, $cm, $forum, $discussion, $post, $ratings, $reply, $forumtracked, $posts)) {
                $ratingsmenuused = true;
            }
//.........这里部分代码省略.........

 public function load_data()
 {
     global $DB;
     if ($this->postid) {
         if (!($this->post = $DB->get_record('forum_posts', array('id' => $this->postid)))) {
             throw new portfolio_caller_exception('invalidpostid', 'forum');
         }
     }
     $dparams = array();
     if ($this->discussionid) {
         $dbparams = array('id' => $this->discussionid);
     } else {
         if ($this->post) {
             $dbparams = array('id' => $this->post->discussion);
         } else {
             throw new portfolio_caller_exception('mustprovidediscussionorpost', 'forum');
         }
     }
     if (!($this->discussion = $DB->get_record('forum_discussions', $dbparams))) {
         throw new portfolio_caller_exception('invaliddiscussionid', 'forum');
     }
     if (!($this->forum = $DB->get_record('forum', array('id' => $this->discussion->forum)))) {
         throw new portfolio_caller_exception('invalidforumid', 'forum');
     }
     if (!($this->cm = get_coursemodule_from_instance('forum', $this->forum->id))) {
         throw new portfolio_caller_exception('invalidcoursemodule');
     }
     $modcontext = get_context_instance(CONTEXT_MODULE, $this->cm->id);
     if ($this->post) {
         $this->set_file_and_format_data($this->attachment, $modcontext->id, 'forum_attachment', $this->post->id);
         if (!empty($this->multifiles)) {
             $this->keyedfiles[$this->post->id] = $this->multifiles;
         } else {
             if (!empty($this->singlefile)) {
                 $this->keyedfiles[$this->post->id] = $this->singlefile;
             }
         }
     } else {
         // whole thread
         $fs = get_file_storage();
         $this->posts = forum_get_all_discussion_posts($this->discussion->id, 'p.created ASC');
         $this->multifiles = array();
         foreach ($this->posts as $post) {
             if (!($this->keyedfiles[$post->id] = $fs->get_area_files($modcontext->id, 'forum_attachment', $post->id, "timemodified", false))) {
                 continue;
             }
             $this->multifiles = array_merge($this->multifiles, array_values($this->keyedfiles[$post->id]));
         }
     }
     if ($this->attachment) {
         // do nothing
     } else {
         if (!empty($this->multifiles) || !empty($this->singlefile)) {
             $this->supportedformats = array(PORTFOLIO_FORMAT_FILE, PORTFOLIO_FORMAT_RICHHTML);
         } else {
             $this->supportedformats = array(PORTFOLIO_FORMAT_PLAINHTML);
         }
     }
 }

function leaf_get_newsitem($d)
{
    global $DB, $USER, $CFG, $OUTPUT;
    static $str;
    require_once $CFG->libdir . '/filelib.php';
    $discussion = $DB->get_record('forum_discussions', array('id' => $d, 'course' => 1), '*', MUST_EXIST);
    $course = $DB->get_record('course', array('id' => $discussion->course), '*', MUST_EXIST);
    $forum = $DB->get_record('forum', array('id' => $discussion->forum), '*', MUST_EXIST);
    $cm = get_coursemodule_from_instance('forum', $forum->id, $course->id, false, MUST_EXIST);
    $parent = $discussion->firstpost;
    $post = forum_get_post_full($parent);
    $displaymode = -1;
    $canreply = false;
    $canrate = false;
    $sort = "p.created ASC";
    $posts = forum_get_all_discussion_posts($discussion->id, $sort, false);
    foreach ($posts as $post) {
        $post->course = $course->id;
        $post->forum = $forum->id;
        $postuser = new stdClass();
        $postuser->id = $post->userid;
        $postuser->firstname = $post->firstname;
        $postuser->lastname = $post->lastname;
        $postuser->imagealt = $post->imagealt;
        $postuser->picture = $post->picture;
        $postuser->email = $post->email;
        $postuser->fullname = fullname($postuser);
        $output = '';
        $output .= html_writer::tag('a', '', array('id' => 'p' . $post->id));
        $output .= html_writer::start_tag('div', array('class' => 'forumpost clearfix firstpost starter'));
        $output .= html_writer::start_tag('div', array('class' => 'row header clearfix'));
        $output .= html_writer::start_tag('div', array('class' => 'left picture'));
        $output .= $OUTPUT->user_picture($postuser, array('courseid' => $course->id));
        $output .= html_writer::end_tag('div');
        $output .= html_writer::start_tag('div', array('class' => 'topic  firstpost starter'));
        $postsubject = $post->subject;
        if (empty($post->subjectnoformat)) {
            $postsubject = format_string($postsubject);
        }
        $output .= html_writer::tag('div', $postsubject, array('class' => 'subject'));
        $output .= html_writer::tag('div', $postuser->fullname, array('class' => 'author'));
        $output .= html_writer::end_tag('div');
        //topic
        $output .= html_writer::end_tag('div');
        //row
        $output .= html_writer::start_tag('div', array('class' => 'row maincontent clearfix'));
        $output .= html_writer::start_tag('div', array('class' => 'left'));
        $output .= html_writer::tag('div', ' ', array('class' => 'grouppictures'));
        $output .= html_writer::end_tag('div');
        //left side
        $output .= html_writer::start_tag('div', array('class' => 'no-overflow'));
        $output .= html_writer::start_tag('div', array('class' => 'content'));
        $options = new stdClass();
        $options->para = false;
        $options->trusted = $post->messagetrust;
        // Prepare whole post
        $postclass = 'fullpost';
        $postcontent = format_text($post->message, $post->messageformat, $options, $course->id);
        // Output the post content
        $output .= html_writer::tag('div', $postcontent, array('class' => 'posting ' . $postclass));
        $output .= html_writer::end_tag('div');
        // Content
        $output .= html_writer::end_tag('div');
        // Content mask
        $output .= html_writer::end_tag('div');
        // Row
        $output .= html_writer::start_tag('div', array('class' => 'row side'));
        $output .= html_writer::tag('div', ' ', array('class' => 'left'));
        $output .= html_writer::start_tag('div', array('class' => 'options clearfix'));
        // Close remaining open divs
        $output .= html_writer::end_tag('div');
        // content
        $output .= html_writer::end_tag('div');
        // row
        $output .= html_writer::end_tag('div');
        // forumpost
        echo $output;
    }
}

    /**
     * Returns a list of forum posts for a discussion
     *
     * @param int $discussionid the post ids
     * @param string $sortby sort by this element (id, created or modified)
     * @param string $sortdirection sort direction: ASC or DESC
     *
     * @return array the forum post details
     * @since Moodle 2.7
     */
    public static function get_forum_discussion_posts($discussionid, $sortby = "created", $sortdirection = "DESC") {
        global $CFG, $DB, $USER;

        $posts = array();
        $warnings = array();

        // Validate the parameter.
        $params = self::validate_parameters(self::get_forum_discussion_posts_parameters(),
            array(
                'discussionid' => $discussionid,
                'sortby' => $sortby,
                'sortdirection' => $sortdirection));

        // Compact/extract functions are not recommended.
        $discussionid   = $params['discussionid'];
        $sortby         = $params['sortby'];
        $sortdirection  = $params['sortdirection'];

        $sortallowedvalues = array('id', 'created', 'modified');
        if (!in_array($sortby, $sortallowedvalues)) {
            throw new invalid_parameter_exception('Invalid value for sortby parameter (value: ' . $sortby . '),' .
                'allowed values are: ' . implode(',', $sortallowedvalues));
        }

        $sortdirection = strtoupper($sortdirection);
        $directionallowedvalues = array('ASC', 'DESC');
        if (!in_array($sortdirection, $directionallowedvalues)) {
            throw new invalid_parameter_exception('Invalid value for sortdirection parameter (value: ' . $sortdirection . '),' .
                'allowed values are: ' . implode(',', $directionallowedvalues));
        }

        $discussion = $DB->get_record('forum_discussions', array('id' => $discussionid), '*', MUST_EXIST);
        $forum = $DB->get_record('forum', array('id' => $discussion->forum), '*', MUST_EXIST);
        $course = $DB->get_record('course', array('id' => $forum->course), '*', MUST_EXIST);
        $cm = get_coursemodule_from_instance('forum', $forum->id, $course->id, false, MUST_EXIST);

        // Validate the module context. It checks everything that affects the module visibility (including groupings, etc..).
        $modcontext = context_module::instance($cm->id);
        self::validate_context($modcontext);

        // This require must be here, see mod/forum/discuss.php.
        require_once($CFG->dirroot . "/mod/forum/lib.php");

        // Check they have the view forum capability.
        require_capability('mod/forum:viewdiscussion', $modcontext, null, true, 'noviewdiscussionspermission', 'forum');

        if (! $post = forum_get_post_full($discussion->firstpost)) {
            throw new moodle_exception('notexists', 'forum');
        }

        // This function check groups, qanda, timed discussions, etc.
        if (!forum_user_can_see_post($forum, $discussion, $post, null, $cm)) {
            throw new moodle_exception('noviewdiscussionspermission', 'forum');
        }

        $canviewfullname = has_capability('moodle/site:viewfullnames', $modcontext);

        // We will add this field in the response.
        $canreply = forum_user_can_post($forum, $discussion, $USER, $cm, $course, $modcontext);

        $forumtracked = forum_tp_is_tracked($forum);

        $sort = 'p.' . $sortby . ' ' . $sortdirection;
        $allposts = forum_get_all_discussion_posts($discussion->id, $sort, $forumtracked);

        foreach ($allposts as $post) {

            if (!forum_user_can_see_post($forum, $discussion, $post, null, $cm)) {
                $warning = array();
                $warning['item'] = 'post';
                $warning['itemid'] = $post->id;
                $warning['warningcode'] = '1';
                $warning['message'] = 'You can\'t see this post';
                $warnings[] = $warning;
                continue;
            }

            // Function forum_get_all_discussion_posts adds postread field.
            // Note that the value returned can be a boolean or an integer. The WS expects a boolean.
            if (empty($post->postread)) {
                $post->postread = false;
            } else {
                $post->postread = true;
            }

            $post->canreply = $canreply;
            if (!empty($post->children)) {
                $post->children = array_keys($post->children);
            } else {
                $post->children = array();
//.........这里部分代码省略.........