/**
* This function returns a list of the page images from a pdf.
*
* The readonly version is different than the normal one. The readonly version contains a copy
* of the pages in the state they were when the PDF was annotated, by doing so we prevent the
* the pages that are displayed to change as soon as the submission changes.
*
* Though there is an edge case, if the PDF was annotated before MDL-45580, then it is possible
* that we do not find any readonly version of the pages. In that case, we will get the normal
* pages and copy them to the readonly area. This ensures that the pages will remain in that
* state until the submission is updated. When the normal files do not exist, we throw an exception
* because the readonly pages should only ever be displayed after a teacher has annotated the PDF,
* they would not exist until they do.
*
* @param int|\assign $assignment
* @param int $userid
* @param int $attemptnumber (-1 means latest attempt)
* @param bool $readonly If true, then we are requesting the readonly version.
* @return array(stored_file)
*/
public static function get_page_images_for_attempt($assignment, $userid, $attemptnumber, $readonly = false)
{
$assignment = self::get_assignment_from_param($assignment);
if (!$assignment->can_view_submission($userid)) {
\print_error('nopermission');
}
if ($assignment->get_instance()->teamsubmission) {
$submission = $assignment->get_group_submission($userid, 0, false, $attemptnumber);
} else {
$submission = $assignment->get_user_submission($userid, false, $attemptnumber);
}
$grade = $assignment->get_user_grade($userid, true, $attemptnumber);
$contextid = $assignment->get_context()->id;
$component = 'assignfeedback_editpdf';
$itemid = $grade->id;
$filepath = '/';
$filearea = self::PAGE_IMAGE_FILEAREA;
$fs = \get_file_storage();
// If we are after the readonly pages...
if ($readonly) {
$filearea = self::PAGE_IMAGE_READONLY_FILEAREA;
if ($fs->is_area_empty($contextid, $component, $filearea, $itemid)) {
// We have a problem here, we were supposed to find the files.
// Attempt to re-generate the pages from the combined images.
self::generate_page_images_for_attempt($assignment, $userid, $attemptnumber);
self::copy_pages_to_readonly_area($assignment, $grade);
}
}
$files = $fs->get_directory_files($contextid, $component, $filearea, $itemid, $filepath);
$pages = array();
if (!empty($files)) {
$first = reset($files);
if (!$readonly && $first->get_timemodified() < $submission->timemodified) {
// Image files are stale, we need to regenerate them, except in readonly mode.
// We also need to remove the draft annotations and comments associated with this attempt.
$fs->delete_area_files($contextid, $component, $filearea, $itemid);
page_editor::delete_draft_content($itemid);
$files = array();
} else {
// Need to reorder the files following their name.
// because get_directory_files() return a different order than generate_page_images_for_attempt().
foreach ($files as $file) {
// Extract the page number from the file name image_pageXXXX.png.
preg_match('/page([\\d]+)\\./', $file->get_filename(), $matches);
if (empty($matches) or !is_numeric($matches[1])) {
throw new \coding_exception("'" . $file->get_filename() . "' file hasn't the expected format filename: image_pageXXXX.png.");
}
$pagenumber = (int) $matches[1];
// Save the page in the ordered array.
$pages[$pagenumber] = $file;
}
ksort($pages);
}
}
if (empty($pages)) {
if ($readonly) {
// This should never happen, there should be a version of the pages available
// whenever we are requesting the readonly version.
throw new \moodle_exception('Could not find readonly pages for grade ' . $grade->id);
}
$pages = self::generate_page_images_for_attempt($assignment, $userid, $attemptnumber);
}
return $pages;
}
