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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* This file contains the combined document class for the assignfeedback_editpdf plugin.
*
* @package assignfeedback_editpdf
* @copyright 2017 Andrew Nicols <andrew@nicols.co.uk>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace assignfeedback_editpdf;
defined('MOODLE_INTERNAL') || die();
/**
* The combined_document class for the assignfeedback_editpdf plugin.
*
* @copyright 2017 Andrew Nicols <andrew@nicols.co.uk>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class combined_document {
/**
* Status value representing a conversion waiting to start.
*/
const STATUS_PENDING_INPUT = 0;
/**
* Status value representing all documents ready to be combined.
*/
const STATUS_READY = 1;
/**
* Status value representing all documents are ready to be combined as are supported.
*/
const STATUS_READY_PARTIAL = 3;
/**
* Status value representing a successful conversion.
*/
const STATUS_COMPLETE = 2;
/**
* Status value representing a permanent error.
*/
const STATUS_FAILED = -1;
/**
* The list of files which make this document.
*/
protected $sourcefiles = [];
/**
* The resultant combined file.
*/
protected $combinedfile;
/**
* The combination status.
*/
protected $combinationstatus = null;
/**
* The number of pages in the combined PDF.
*/
protected $pagecount = 0;
/**
* Check the current status of the document combination.
* Note that the combined document may not contain all the source files if some of the
* source files were not able to be converted. An example is an audio file with a pdf cover sheet. Only
* the cover sheet will be included in the combined document.
*
* @return int
*/
public function get_status() {
if ($this->combinedfile) {
// The combined file exists. Report success.
return self::STATUS_COMPLETE;
}
if (empty($this->sourcefiles)) {
// There are no source files to combine.
return self::STATUS_FAILED;
}
if (!empty($this->combinationstatus)) {
// The combination is in progress and has set a status.
// Return it instead.
return $this->combinationstatus;
}
$pending = false;
$partial = false;
foreach ($this->sourcefiles as $file) {
// The combined file has not yet been generated.
// Check the status of each source file.
if (is_a($file, \core_files\conversion::class)) {
$status = $file->get('status');
switch ($status) {
case \core_files\conversion::STATUS_IN_PROGRESS:
case \core_files\conversion::STATUS_PENDING:
$pending = true;
break;
// There are 4 status flags, so the only remaining one is complete which is fine.
case \core_files\conversion::STATUS_FAILED:
$partial = true;
break;
}
}
}
if ($pending) {
return self::STATUS_PENDING_INPUT;
} else {
if ($partial) {
return self::STATUS_READY_PARTIAL;
}
return self::STATUS_READY;
}
}
/**
* Set the completed combined file.
*
* @param stored_file $file The completed document for all files to be combined.
* @return $this
*/
public function set_combined_file($file) {
$this->combinedfile = $file;
return $this;
}
/**
* Return true of the combined file contained only some of the submission files.
*
* @return boolean
*/
public function is_partial_conversion() {
$combinedfile = $this->get_combined_file();
if (empty($combinedfile)) {
return false;
}
$filearea = $combinedfile->get_filearea();
return $filearea == document_services::PARTIAL_PDF_FILEAREA;
}
/**
* Retrieve the completed combined file.
*
* @return stored_file
*/
public function get_combined_file() {
return $this->combinedfile;
}
/**
* Set all source files which are to be combined.
*
* @param stored_file|conversion[] $files The complete list of all source files to be combined.
* @return $this
*/
public function set_source_files($files) {
$this->sourcefiles = $files;
return $this;
}
/**
* Add an additional source file to the end of the existing list.
*
* @param stored_file|conversion $file The file to add to the end of the list.
* @return $this
*/
public function add_source_file($file) {
$this->sourcefiles[] = $file;
return $this;
}
/**
* Retrieve the complete list of source files.
*
* @return stored_file|conversion[]
*/
public function get_source_files() {
return $this->sourcefiles;
}
/**
* Refresh the files.
*
* This includes polling any pending conversions to see if they are complete.
*
* @return $this
*/
public function refresh_files() {
$converter = new \core_files\converter();
foreach ($this->sourcefiles as $file) {
if (is_a($file, \core_files\conversion::class)) {
$status = $file->get('status');
switch ($status) {
case \core_files\conversion::STATUS_COMPLETE:
continue 2;
break;
default:
$converter->poll_conversion($conversion);
}
}
}
return $this;
}
/**
* Combine all source files into a single PDF and store it in the
* file_storage API using the supplied contextid and itemid.
*
* @param int $contextid The contextid for the file to be stored under
* @param int $itemid The itemid for the file to be stored under
* @return $this
*/
public function combine_files($contextid, $itemid) {
global $CFG;
$currentstatus = $this->get_status();
$readystatuslist = [self::STATUS_READY, self::STATUS_READY_PARTIAL];
if ($currentstatus === self::STATUS_FAILED) {
$this->store_empty_document($contextid, $itemid);
return $this;
} else if (!in_array($currentstatus, $readystatuslist)) {
// The document is either:
// * already combined; or
// * pending input being fully converted; or
// * unable to continue due to an issue with the input documents.
//
// Exit early as we cannot continue.
return $this;
}
require_once($CFG->libdir . '/pdflib.php');
$pdf = new pdf();
$files = $this->get_source_files();
$compatiblepdfs = [];
foreach ($files as $file) {
// Check that each file is compatible and add it to the list.
// Note: We drop non-compatible files.
$compatiblepdf = false;
if (is_a($file, \core_files\conversion::class)) {
$status = $file->get('status');
if ($status == \core_files\conversion::STATUS_COMPLETE) {
$compatiblepdf = pdf::ensure_pdf_compatible($file->get_destfile());
}
} else {
$compatiblepdf = pdf::ensure_pdf_compatible($file);
}
if ($compatiblepdf) {
$compatiblepdfs[] = $compatiblepdf;
}
}
$tmpdir = make_request_directory();
$tmpfile = $tmpdir . '/' . document_services::COMBINED_PDF_FILENAME;
try {
$pagecount = $pdf->combine_pdfs($compatiblepdfs, $tmpfile);
$pdf->Close();
} catch (\Exception $e) {
// Unable to combine the PDF.
debugging('TCPDF could not process the pdf files:' . $e->getMessage(), DEBUG_DEVELOPER);
$pdf->Close();
return $this->mark_combination_failed();
}
// Verify the PDF.
$verifypdf = new pdf();
$verifypagecount = $verifypdf->load_pdf($tmpfile);
$verifypdf->Close();
if ($verifypagecount <= 0) {
// No pages were found in the combined PDF.
return $this->mark_combination_failed();
}
// Store the newly created file as a stored_file.
$this->store_combined_file($tmpfile, $contextid, $itemid, ($currentstatus == self::STATUS_READY_PARTIAL));
// Note the verified page count.
$this->pagecount = $verifypagecount;
return $this;
}
/**
* Mark the combination attempt as having encountered a permanent failure.
*
* @return $this
*/
protected function mark_combination_failed() {
$this->combinationstatus = self::STATUS_FAILED;
return $this;
}
/**
* Store the combined file in the file_storage API.
*
* @param string $tmpfile The path to the file on disk to be stored.
* @param int $contextid The contextid for the file to be stored under
* @param int $itemid The itemid for the file to be stored under
* @param boolean $partial The combined pdf contains only some of the source files.
* @return $this
*/
protected function store_combined_file($tmpfile, $contextid, $itemid, $partial = false) {
// Store the file.
$record = $this->get_stored_file_record($contextid, $itemid, $partial);
$fs = get_file_storage();
// Delete existing files first.
$fs->delete_area_files($record->contextid, $record->component, $record->filearea, $record->itemid);
// This was a combined pdf.
$file = $fs->create_file_from_pathname($record, $tmpfile);
$this->set_combined_file($file);
return $this;
}
/**
* Store the empty document file in the file_storage API.
*
* @param int $contextid The contextid for the file to be stored under
* @param int $itemid The itemid for the file to be stored under
* @return $this
*/
protected function store_empty_document($contextid, $itemid) {
// Store the file.
$record = $this->get_stored_file_record($contextid, $itemid);
$fs = get_file_storage();
// Delete existing files first.
$fs->delete_area_files($record->contextid, $record->component, $record->filearea, $record->itemid);
$file = $fs->create_file_from_string($record, base64_decode(document_services::BLANK_PDF_BASE64));
$this->pagecount = 1;
$this->set_combined_file($file);
return $this;
}
/**
* Get the total number of pages in the combined document.
*
* If there are no pages, or it is not yet possible to count them a
* value of 0 is returned.
*
* @return int
*/
public function get_page_count() {
if ($this->pagecount) {
return $this->pagecount;
}
$status = $this->get_status();
if ($status === self::STATUS_FAILED) {
// The empty document will be returned.
return 1;
}
if ($status !== self::STATUS_COMPLETE) {
// No pages yet.
return 0;
}
// Load the PDF to determine the page count.
$temparea = make_request_directory();
$tempsrc = $temparea . "/source.pdf";
$this->get_combined_file()->copy_content_to($tempsrc);
$pdf = new pdf();
$pagecount = $pdf->load_pdf($tempsrc);
$pdf->Close();
if ($pagecount <= 0) {
// Something went wrong. Return an empty page count again.
return 0;
}
$this->pagecount = $pagecount;
return $this->pagecount;
}
/**
* Get the total number of documents to be combined.
*
* @return int
*/
public function get_document_count() {
return count($this->sourcefiles);
}
/**
* Helper to fetch the stored_file record.
*
* @param int $contextid The contextid for the file to be stored under
* @param int $itemid The itemid for the file to be stored under
* @param boolean $partial The combined file contains only some of the source files.
* @return stdClass
*/
protected function get_stored_file_record($contextid, $itemid, $partial = false) {
$filearea = document_services::COMBINED_PDF_FILEAREA;
if ($partial) {
$filearea = document_services::PARTIAL_PDF_FILEAREA;
}
return (object) [
'contextid' => $contextid,
'component' => 'assignfeedback_editpdf',
'filearea' => $filearea,
'itemid' => $itemid,
'filepath' => '/',
'filename' => document_services::COMBINED_PDF_FILENAME,
];
}
}