Astra_Customizer_Sanitizes::sanitize_svg_code( string $original_content )

		public static function sanitize_svg_code( $original_content ) {

			if ( ! $original_content ) {
				return '';
			}

			// Define allowed tags and attributes.
			$allowed_tags = apply_filters( 'astra_custom_svg_allowed_tags', array( 'a', 'circle', 'clippath', 'defs', 'style', 'desc', 'ellipse', 'fegaussianblur', 'filter', 'foreignobject', 'g', 'image', 'line', 'lineargradient', 'marker', 'mask', 'metadata', 'path', 'pattern', 'polygon', 'polyline', 'radialgradient', 'rect', 'stop', 'svg', 'switch', 'symbol', 'text', 'textpath', 'title', 'tspan', 'use' ) );

			$allowed_attributes = apply_filters( 'astra_custom_svg_allowed_attributes', array( 'class', 'clip-path', 'clip-rule', 'fill-opacity', 'fill-rule', 'filter', 'id', 'mask', 'opacity', 'stroke', 'stroke-dasharray', 'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin', 'stroke-miterlimit', 'stroke-opacity', 'stroke-width', 'style', 'systemlanguage', 'transform', 'href', 'xlink:href', 'xlink:title', 'cx', 'cy', 'r', 'requiredfeatures', 'clippathunits', 'type', 'rx', 'ry', 'color-interpolation-filters', 'stddeviation', 'filterres', 'filterunits', 'primitiveunits', 'x', 'y', 'font-size', 'display', 'font-family', 'font-style', 'font-weight', 'text-anchor', 'marker-end', 'marker-mid', 'marker-start', 'x1', 'x2', 'y1', 'y2', 'gradienttransform', 'gradientunits', 'spreadmethod', 'markerheight', 'markerunits', 'markerwidth', 'orient', 'preserveaspectratio', 'refx', 'refy', 'maskcontentunits', 'maskunits', 'd', 'patterncontentunits', 'patterntransform', 'patternunits', 'points', 'fx', 'fy', 'offset', 'stop-color', 'stop-opacity', 'xmlns', 'xmlns:se', 'xmlns:xlink', 'xml:space', 'method', 'spacing', 'startoffset', 'dx', 'dy', 'rotate', 'textlength', 'viewbox' ) );

			$is_encoded = false;

			$needle = "\x1f\x8b\x08";
			if ( function_exists( 'mb_strpos' ) ) {
				$is_encoded = 0 === mb_strpos( $original_content, $needle );
			} else {
				$is_encoded = 0 === strpos( $original_content, $needle );
			}

			if ( $is_encoded ) {
				$original_content = gzdecode( $original_content );
				if ( $original_content === false ) {
					return '';
				}
			}

			// Strip php tags.
			$content = preg_replace( '/<\?(=|php)(.+?)\?>/i', '', $original_content );
			$content = preg_replace( '/<\?(.*)\?>/Us', '', $content );
			$content = preg_replace( '/<\%(.*)\%>/Us', '', $content );

			if ( ( false !== strpos( $content, '<?php' ) ) || ( false !== strpos( $content, '<%' ) ) ) {
				return '';
			}

			// Strip comments.
			$content = preg_replace( '/<!--(.*)-->/Us', '', $content );
			$content = preg_replace( '/\/\*(.*)\*\//Us', '', $content );

			if ( ( false !== strpos( $content, '<!--' ) ) || ( false !== strpos( $content, '/*' ) ) ) {
				return '';
			}

			// Strip line breaks.
			$content = preg_replace( '/\r|\n/', '', $content );

			// Find the start and end tags so we can cut out miscellaneous garbage.
			$start = strpos( $content, '<svg' );
			$end   = strrpos( $content, '</svg>' );
			if ( false === $start || false === $end ) {
				return '';
			}

			$content = substr( $content, $start, ( $end - $start + 6 ) );

			// If the server's PHP version is 8 or up, make sure to disable the ability to load external entities.
			$php_version_under_eight = version_compare( PHP_VERSION, '8.0.0', '<' );
			if ( $php_version_under_eight ) {
				$libxml_disable_entity_loader = libxml_disable_entity_loader( true );
			}
			// Suppress the errors.
			$libxml_use_internal_errors = libxml_use_internal_errors( true );

			// Create DOMDocument instance.
			$dom                      = new DOMDocument();
			$dom->formatOutput        = false;
			$dom->preserveWhiteSpace  = false;
			$dom->strictErrorChecking = false;

			$open_svg = (bool) $content ? $dom->loadXML( $content ) : false;
			if ( ! $open_svg ) {
				return '';
			}

			// Strip Doctype.
			foreach ( $dom->childNodes as $child ) {
				if ( XML_DOCUMENT_TYPE_NODE === $child->nodeType && (bool) $child->parentNode ) {
					$child->parentNode->removeChild( $child );
				}
			}

			// Sanitize elements.
			$elements = $dom->getElementsByTagName( '*' );
			for ( $index = $elements->length - 1; $index >= 0; $index-- ) {
				$current_element = $elements->item( $index );
				if ( ! in_array( strtolower( $current_element->tagName ), $allowed_tags ) ) {
					$current_element->parentNode->removeChild( $current_element );
					continue;
				}

				// Validate allowed attributes.
				for ( $i = $current_element->attributes->length - 1; $i >= 0; $i-- ) {
					$attr_name           = $current_element->attributes->item( $i )->name;
					$attr_name_lowercase = strtolower( $attr_name );
					if ( ! in_array( $attr_name_lowercase, $allowed_attributes ) &&
						! preg_match( '/^aria-/', $attr_name_lowercase ) &&
						! preg_match( '/^data-/', $attr_name_lowercase ) ) {
						$current_element->removeAttribute( $attr_name );
						continue;
					}

					$attr_value = $current_element->attributes->item( $i )->value;
					if ( ! empty( $attr_value ) &&
						( preg_match( '/^((https?|ftp|file):)?\/\//i', $attr_value ) ||
						preg_match( '/base64|data|(?:java)?script|alert\(|window\.|document/i', $attr_value ) ) ) {
						$current_element->removeAttribute( $attr_name );
						continue;
					}
				}

				// Strip xlink:href.
				$xlink_href = $current_element->getAttributeNS( 'http://www.w3.org/1999/xlink', 'href' );
				if ( $xlink_href && strpos( $xlink_href, '#' ) !== 0 ) {
					$current_element->removeAttributeNS( 'http://www.w3.org/1999/xlink', 'href' );
				}

				// Strip use tag with external references.
				if ( strtolower( $current_element->tagName ) === 'use' ) {
					$xlink_href = $current_element->getAttributeNS( 'http://www.w3.org/1999/xlink', 'href' );
					if ( $current_element->parentNode && $xlink_href && strpos( $xlink_href, '#' ) !== 0 ) {
						$current_element->parentNode->removeChild( $current_element );
					}
				}
			}

			// Export sanitized SVG to string.
			$sanitized = $dom->saveXML( $dom->documentElement, LIBXML_NOEMPTYTAG );

			// Restore defaults.
			if ( $php_version_under_eight && isset( $libxml_disable_entity_loader ) ) {
				libxml_disable_entity_loader( $libxml_disable_entity_loader );
			}
			libxml_use_internal_errors( $libxml_use_internal_errors );

			return $sanitized;
		}