src/Phan/ForkPool/Reader.php
<?php
declare(strict_types=1);
namespace Phan\ForkPool;
use Closure;
use Phan\Library\StringUtil;
use TypeError;
/**
* This reads messages from a forked worker.
* This reuses code from ProtocolStreamReader.
*
* This is designed to accept notifications in a similar format to JSON-RPC (arbitrarily).
* @internal
*/
class Reader
{
public const PARSE_HEADERS = 1;
public const PARSE_BODY = 2;
/** @var resource */
private $input;
/** @var string the bytes read from the worker */
private $buffer = '';
/** @var 1|2 either PARSE_HEADERS or PARSE_BODY */
private $parsing_mode = self::PARSE_HEADERS;
/** @var int the length of the body of the next notification. */
private $content_length;
/** @var string the type of the next notification. */
private $notification_type;
/** @var array<string,string> the JSON-RPC headers. Currently just Content-Length. */
private $headers;
/** @var Closure(string,string):void $notification_handler */
private $notification_handler;
/** @var array<string,int> $read_messages the count of read messages of each type */
private $read_messages = [];
/** @var bool was the end of the input stream reached */
private $eof = false;
/**
* @param resource $input
* @param Closure(string,string):void $notification_handler
*/
public function __construct($input, Closure $notification_handler)
{
if (!\is_resource($input)) {
throw new TypeError('Expected resource for $input, got ' . \gettype($input));
}
$this->input = $input;
$this->notification_handler = $notification_handler;
}
/**
* Read serialized messages from the analysis workers
*/
public function readMessages(): void
{
if ($this->eof) {
return;
}
while (($c = \fgetc($this->input)) !== false && $c !== '') {
$this->buffer .= $c;
switch ($this->parsing_mode) {
case self::PARSE_HEADERS:
if ($this->buffer === "\r\n") {
$this->parsing_mode = self::PARSE_BODY;
$this->content_length = (int)$this->headers['Content-Length'];
$this->notification_type = $this->headers['Notification-Type'] ?? 'unknown';
$this->buffer = '';
} elseif (\substr($this->buffer, -2) === "\r\n") {
$parts = \explode(':', $this->buffer);
$this->headers[$parts[0]] = \trim($parts[1]);
$this->buffer = '';
}
break;
case self::PARSE_BODY:
if (\strlen($this->buffer) < $this->content_length) {
// We know the number of remaining bytes to read - try to read them all at once.
$buf = \fread($this->input, $this->content_length - \strlen($this->buffer));
if (\is_string($buf) && \strlen($buf) > 0) {
$this->buffer .= $buf;
}
}
if (\strlen($this->buffer) === $this->content_length) {
$this->read_messages[$this->notification_type] = ($this->read_messages[$this->notification_type] ?? 0) + 1;
($this->notification_handler)($this->notification_type, $this->buffer);
$this->parsing_mode = self::PARSE_HEADERS;
$this->headers = [];
$this->buffer = '';
}
break;
}
}
$this->eof = \feof($this->input);
}
/**
* Returns an error message for errors caused by an analysis worker exiting abnormally or sending invalid data.
* During normal operation, should return null.
*/
public function computeErrorsAfterRead(): ?string
{
$error = "";
if (StringUtil::isNonZeroLengthString($this->buffer)) {
$error .= \sprintf("Saw non-empty buffer of length %d\n", \strlen($this->buffer));
}
if ($this->parsing_mode !== self::PARSE_HEADERS) {
$error .= "Expected to be finished parsing the last message body\n";
}
if (!$this->eof) {
$error .= "Expected to reach eof\n";
}
if (!isset($this->read_messages[Writer::TYPE_ISSUE_LIST])) {
$error .= "Expected to have received a list of 0 or more issues (as the last notification)\n";
}
return $error !== '' ? $error : null;
}
}