insert_with_markers( string $filename, string $marker, array|string $insertion ): bool

114function insert_with_markers( $filename, $marker, $insertion ) {115	if ( ! file_exists( $filename ) ) {116		if ( ! is_writable( dirname( $filename ) ) ) {117			return false;118		}119 120		if ( ! touch( $filename ) ) {121			return false;122		}123 124		// Make sure the file is created with a minimum set of permissions.125		$perms = fileperms( $filename );126 127		if ( $perms ) {128			chmod( $filename, $perms | 0644 );129		}130	} elseif ( ! is_writable( $filename ) ) {131		return false;132	}133 134	if ( ! is_array( $insertion ) ) {135		$insertion = explode( "\n", $insertion );136	}137 138	$switched_locale = switch_to_locale( get_locale() );139 140	$instructions = sprintf(141		/* translators: 1: Marker. */142		__(143			'The directives (lines) between "BEGIN %1$s" and "END %1$s" are144dynamically generated, and should only be modified via WordPress filters.145Any changes to the directives between these markers will be overwritten.'146		),147		$marker148	);149 150	$instructions = explode( "\n", $instructions );151 152	foreach ( $instructions as $line => $text ) {153		$instructions[ $line ] = '# ' . $text;154	}155 156	/**157	 * Filters the inline instructions inserted before the dynamically generated content.158	 *159	 * @since 5.3.0160	 *161	 * @param string[] $instructions Array of lines with inline instructions.162	 * @param string   $marker       The marker being inserted.163	 */164	$instructions = apply_filters( 'insert_with_markers_inline_instructions', $instructions, $marker );165 166	if ( $switched_locale ) {167		restore_previous_locale();168	}169 170	$insertion = array_merge( $instructions, $insertion );171 172	$start_marker = "# BEGIN {$marker}";173	$end_marker   = "# END {$marker}";174 175	$fp = fopen( $filename, 'r+' );176 177	if ( ! $fp ) {178		return false;179	}180 181	// Attempt to get a lock. If the filesystem supports locking, this will block until the lock is acquired.182	flock( $fp, LOCK_EX );183 184	$lines = array();185 186	while ( ! feof( $fp ) ) {187		$lines[] = rtrim( fgets( $fp ), "\r\n" );188	}189 190	// Split out the existing file into the preceding lines, and those that appear after the marker.191	$pre_lines        = array();192	$post_lines       = array();193	$existing_lines   = array();