MDL-31675 File browsing support for the Forum module

AMOS BEGIN
 CPY [attachments,mod_forum],[areaattachment,mod_forum]
AMOS END

mod/forum/lang/en/forum.php

@@ -35,6 +35,8 @@ $string['allsubscribe'] = 'Subscribe to all forums';
 $string['allunsubscribe'] = 'Unsubscribe from all forums';
 $string['alreadyfirstpost'] = 'This is already the first post in the discussion';
 $string['anyfile'] = 'Any file';
+$string['areaattachment'] = 'Attachments';
+$string['areapost'] = 'Messages';
 $string['attachment'] = 'Attachment';
 $string['attachment_help'] = 'You can optionally attach one or more files to a forum post. If you attach an image, it will be displayed after the message.';
 $string['attachmentnopost'] = 'You cannot export attachments without a post id';

mod/forum/lib.php

@@ -4014,6 +4014,10 @@ function forum_print_attachments($post, $cm, $type) {
     }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+// File API                                                                   //
+////////////////////////////////////////////////////////////////////////////////
+
 /**
  * Lists all browsable file areas
  *
@@ -4025,8 +4029,10 @@ function forum_print_attachments($post, $cm, $type) {
  * @return array
  */
 function forum_get_file_areas($course, $cm, $context) {
-    $areas = array();
-    return $areas;
+    return array(
+        'attachment' => get_string('areaattachment', 'mod_forum'),
+        'post' => get_string('areapost', 'mod_forum'),
+    );
 }
 
 /**
@@ -4052,11 +4058,28 @@ function forum_get_file_info($browser, $areas, $course, $cm, $context, $filearea
         return null;
     }
 
-    $fileareas = array('attachment', 'post');
-    if (!in_array($filearea, $fileareas)) {
+    // filearea must contain a real area
+    if (!isset($areas[$filearea])) {
         return null;
     }
 
+    // this is enforced by {@link file_info_context_course} currently
+    if (!has_capability('moodle/course:managefiles', $context)) {
+        return null;
+    }
+
+    // Note that forum_user_can_see_post() additionally allows access for parent roles
+    // and it explicitly checks qanda forum type, too. One day, when we stop requiring
+    // course:managefiles, we will need to extend this.
+    if (!has_capability('mod/forum:viewdiscussion', $context)) {
+        return null;
+    }
+
+    if (is_null($itemid)) {
+        require_once($CFG->dirroot.'/mod/forum/locallib.php');
+        return new forum_file_info_container($browser, $course, $cm, $context, $areas, $filearea);
+    }
+
     if (!$post = $DB->get_record('forum_posts', array('id' => $itemid))) {
         return null;
     }
@@ -4092,7 +4115,7 @@ function forum_get_file_info($browser, $areas, $course, $cm, $context, $filearea
     }
 
     $urlbase = $CFG->wwwroot.'/pluginfile.php';
-    return new file_info_stored($browser, $context, $storedfile, $urlbase, $filearea, $itemid, true, true, false);
+    return new file_info_stored($browser, $context, $storedfile, $urlbase, $itemid, true, true, false, false);
 }
 
 /**
@@ -4118,8 +4141,10 @@ function forum_pluginfile($course, $cm, $context, $filearea, $args, $forcedownlo
 
     require_course_login($course, true, $cm);
 
-    $fileareas = array('attachment', 'post');
-    if (!in_array($filearea, $fileareas)) {
+    $areas = forum_get_file_areas($course, $cm, $context);
+
+    // filearea must contain a real area
+    if (!isset($areas[$filearea])) {
         return false;
     }
 

mod/forum/locallib.php

@@ -391,3 +391,119 @@ class forum_portfolio_caller extends portfolio_module_caller_base {
         return array(PORTFOLIO_FORMAT_FILE, PORTFOLIO_FORMAT_RICHHTML, PORTFOLIO_FORMAT_PLAINHTML, PORTFOLIO_FORMAT_LEAP2A);
     }
 }
+
+
+/**
+ * Class representing the virtual node with all itemids in the file browser
+ *
+ * @category  files
+ * @copyright 2012 David Mudrak <david@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class forum_file_info_container extends file_info {
+    /** @var file_browser */
+    protected $browser;
+    /** @var stdClass */
+    protected $course;
+    /** @var stdClass */
+    protected $cm;
+    /** @var string */
+    protected $component;
+    /** @var stdClass */
+    protected $context;
+    /** @var array */
+    protected $areas;
+    /** @var string */
+    protected $filearea;
+
+    /**
+     * Constructor (in case you did not realize it ;-)
+     *
+     * @param file_browser $browser
+     * @param stdClass $course
+     * @param stdClass $cm
+     * @param stdClass $context
+     * @param array $areas
+     * @param string $filearea
+     */
+    public function __construct($browser, $course, $cm, $context, $areas, $filearea) {
+        parent::__construct($browser, $context);
+        $this->browser = $browser;
+        $this->course = $course;
+        $this->cm = $cm;
+        $this->component = 'mod_forum';
+        $this->context = $context;
+        $this->areas = $areas;
+        $this->filearea = $filearea;
+    }
+
+    /**
+     * @return array with keys contextid, filearea, itemid, filepath and filename
+     */
+    public function get_params() {
+        return array(
+            'contextid' => $this->context->id,
+            'component' => $this->component,
+            'filearea' => $this->filearea,
+            'itemid' => null,
+            'filepath' => null,
+            'filename' => null,
+        );
+    }
+
+    /**
+     * Can new files or directories be added via the file browser
+     *
+     * @return bool
+     */
+    public function is_writable() {
+        return false;
+    }
+
+    /**
+     * Should this node be considered as a folder in the file browser
+     *
+     * @return bool
+     */
+    public function is_directory() {
+        return true;
+    }
+
+    /**
+     * Returns localised visible name of this node
+     *
+     * @return string
+     */
+    public function get_visible_name() {
+        return $this->areas[$this->filearea];
+    }
+
+    /**
+     * Returns list of children nodes
+     *
+     * @return array of file_info instances
+     */
+    public function get_children() {
+        global $DB;
+
+        $children = array();
+        $itemids = $DB->get_records('files', array('contextid' => $this->context->id, 'component' => $this->component,
+            'filearea' => $this->filearea), 'itemid DESC', "DISTINCT itemid");
+        foreach ($itemids as $itemid => $unused) {
+            if ($child = $this->browser->get_file_info($this->context, 'mod_forum', $this->filearea, $itemid)) {
+                $children[] = $child;
+            }
+        }
+
+        return $children;
+    }
+
+    /**
+     * Returns parent file_info instance
+     *
+     * @return file_info or null for root
+     */
+    public function get_parent() {
+        return $this->browser->get_file_info($this->context);
+    }
+}