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<?php
/**
* Copyright © Magento, Inc. All rights reserved.
* See COPYING.txt for license details.
*/
declare(strict_types=1);
namespace Magento\MediaGalleryMetadata\Model\Gif\Segment;
use Magento\MediaGalleryMetadata\Model\AddXmpMetadata;
use Magento\MediaGalleryMetadata\Model\XmpTemplate;
use Magento\MediaGalleryMetadataApi\Api\Data\MetadataInterface;
use Magento\MediaGalleryMetadataApi\Model\FileInterface;
use Magento\MediaGalleryMetadataApi\Model\FileInterfaceFactory;
use Magento\MediaGalleryMetadataApi\Model\SegmentInterface;
use Magento\MediaGalleryMetadataApi\Model\SegmentInterfaceFactory;
use Magento\MediaGalleryMetadataApi\Model\WriteMetadataInterface;
/**
* XMP Writer for GIF format
*/
class WriteXmp implements WriteMetadataInterface
{
private const XMP_SEGMENT_NAME = 'XMP DataXMP';
private const XMP_DATA_START_POSITION = 14;
private const MAGIC_TRAILER_START = "\x01\xFF\xFE";
private const MAGIC_TRAILER_END = "\x03\x02\x01\x00\x00";
/**
* @var SegmentInterfaceFactory
*/
private $segmentFactory;
/**
* @var FileInterfaceFactory
*/
private $fileFactory;
/**
* @var AddXmpMetadata
*/
private $addXmpMetadata;
/**
* @var XmpTemplate
*/
private $xmpTemplate;
/**
* @param FileInterfaceFactory $fileFactory
* @param SegmentInterfaceFactory $segmentFactory
* @param AddXmpMetadata $addXmpMetadata
* @param XmpTemplate $xmpTemplate
*/
public function __construct(
FileInterfaceFactory $fileFactory,
SegmentInterfaceFactory $segmentFactory,
AddXmpMetadata $addXmpMetadata,
XmpTemplate $xmpTemplate
) {
$this->fileFactory = $fileFactory;
$this->segmentFactory = $segmentFactory;
$this->addXmpMetadata = $addXmpMetadata;
$this->xmpTemplate = $xmpTemplate;
}
/**
* Add metadata to the file
*
* @param FileInterface $file
* @param MetadataInterface $metadata
* @return FileInterface
*/
public function execute(FileInterface $file, MetadataInterface $metadata): FileInterface
{
$gifSegments = $file->getSegments();
$xmpGifSegments = [];
foreach ($gifSegments as $key => $segment) {
if ($this->isSegmentXmp($segment)) {
$xmpGifSegments[$key] = $segment;
}
}
if (empty($xmpGifSegments)) {
return $this->fileFactory->create([
'path' => $file->getPath(),
'segments' => $this->insertXmpGifSegment($gifSegments, $this->createXmpSegment($metadata))
]);
}
foreach ($xmpGifSegments as $key => $segment) {
$gifSegments[$key] = $this->updateSegment($segment, $metadata);
}
return $this->fileFactory->create([
'path' => $file->getPath(),
'segments' => $gifSegments
]);
}
/**
* Insert XMP segment to gif image segments (at position 3)
*
* @param SegmentInterface[] $segments
* @param SegmentInterface $xmpSegment
* @return SegmentInterface[]
*/
private function insertXmpGifSegment(array $segments, SegmentInterface $xmpSegment): array
{
return array_merge(array_slice($segments, 0, 4), [$xmpSegment], array_slice($segments, 4));
}
/**
* Return XMP template from string
*
* @param string $string
* @param string $start
* @param string $end
*/
private function getXmpData(string $string, string $start, string $end): string
{
$string = ' ' . $string;
$ini = strpos($string, $start);
if ($ini == 0) {
return '';
}
$ini += strlen($start);
$len = strpos($string, $end, $ini) - $ini;
return substr($string, $ini, $len);
}
/**
* Write new segment metadata
*
* @param MetadataInterface $metadata
* @return SegmentInterface
*/
public function createXmpSegment(MetadataInterface $metadata): SegmentInterface
{
$xmpData = $this->xmpTemplate->get();
$xmpSegment = pack("C", ord("!")) . pack("C", 255) . pack("C", 11) .
self::XMP_SEGMENT_NAME . $this->addXmpMetadata->execute($xmpData, $metadata) . "\x01";
/**
* Write Magic trailer 258 bytes see XMP Specification Part 3, 1.1.2 GIF
*/
$i = 255;
while ($i > 0) {
$xmpSegment .= pack("C", $i);
$i--;
}
return $this->segmentFactory->create([
'name' => self::XMP_SEGMENT_NAME,
'data' => $xmpSegment . "\0\0"
]);
}
/**
* Add metadata to the segment
*
* @param SegmentInterface $segment
* @param MetadataInterface $metadata
* @return SegmentInterface
*/
public function updateSegment(SegmentInterface $segment, MetadataInterface $metadata): SegmentInterface
{
$data = $segment->getData();
$start = substr($data, 0, self::XMP_DATA_START_POSITION);
$xmpData = $this->getXmpData($data, self::XMP_SEGMENT_NAME, "\x01");
$end = substr($data, strpos($data, "\x01"));
return $this->segmentFactory->create([
'name' => $segment->getName(),
'data' => $start . $this->addXmpMetadata->execute($xmpData, $metadata) . $end
]);
}
/**
* Check if segment contains XMP data
*
* @param SegmentInterface $segment
* @return bool
*/
private function isSegmentXmp(SegmentInterface $segment): bool
{
return $segment->getName() === self::XMP_SEGMENT_NAME;
}
}