Initx\Driver\FilesystemQueue

Complexity

Total Complexity

22

Size/Duplication

Total Lines	131
Duplicated Lines	0 %

Test Coverage

Coverage

96.97%

Importance

Changes

0

9 Methods

Rating	Name	Duplication	Size	Complexity
A	add()	0	4	2
A	__construct()	0	5	1
A	poll()	0	9	2
A	peek()	0	9	2
A	offer()	0	16	2
B	removeFirstLine()	0	30	6
A	element()	0	9	2
A	readFirstLine()	0	9	3
A	remove()	0	9	2

<?php declare(strict_types=1);

namespace Initx\Driver;

use Initx\Envelope;
use Initx\Exception\IllegalStateException;
use Initx\Exception\NoSuchElementException;
use Initx\Queue;
use JMS\Serializer\SerializerInterface;
use Throwable;

final class FilesystemQueue implements Queue
{
    use HasFallbackSerializer;

    /**
     * @var string
     */
    private $path;

    /**
     * @var SerializerInterface
     */
    private $serializer;

    public function __construct(string $path, SerializerInterface $serializer = null)
    {
        $this->serializer = $serializer;
        $this->path = $path;
        $this->fallbackSerializer();
    }

    public function add(Envelope $envelope): void
    {
        if (!$this->offer($envelope)) {
            throw new IllegalStateException("Could not write to file: {$this->path}");
        }
    }

    public function offer(Envelope $envelope): bool
    {
        $content = $this->serializer->serialize($envelope, 'json').PHP_EOL;
        try {
            $result = (bool)file_put_contents(
                $this->path,
                $content,
                FILE_APPEND
            );
        } catch (Throwable $exception) {
            // There is a contract need to not throw exceptions from offer(e) method,
            // but return false on failure.
            $result = false;
        }

        return $result;
    }

    public function remove(): Envelope
    {
        $envelope = $this->poll();

        if (!$envelope) {
            throw new NoSuchElementException();
        }

        return $envelope;
    }

    public function poll(): ?Envelope
    {
        $firstLine = $this->removeFirstLine();

        if (!$firstLine) {
            return null;
        }

        return $this->serializer->deserialize($firstLine, Envelope::class, 'json');
    }

    public function element(): Envelope
    {
        $envelope = $this->peek();

        if (!$envelope) {
            throw new NoSuchElementException();
        }

        return $envelope;
    }

    public function peek(): ?Envelope
    {
        $firstLine = $this->readFirstLine();

        if (!$firstLine) {
            return null;
        }

        return $this->serializer->deserialize($firstLine, Envelope::class, 'json');
    }

    private function removeFirstLine(): ?string
    {
        if (!file_exists($this->path)) {
            throw new IllegalStateException("File $this->path not exists");
        }
        $firstLine = null;
        if ($handle = fopen($this->path, 'cb+')) {
            if (!flock($handle, LOCK_EX)) {
                fclose($handle);
            }
            $offset = 0;
            $len = filesize($this->path);
            while (($line = fgets($handle, 4096)) !== false) {
                if (!$firstLine) {
                    $firstLine = $line;
                    $offset = strlen($firstLine);
                    continue;
                }
                $pos = ftell($handle);
                fseek($handle, $pos - strlen($line) - $offset);
                fwrite($handle, $line);
                fseek($handle, $pos);
            }
            fflush($handle);
            ftruncate($handle, $len - $offset);
            flock($handle, LOCK_UN);
            fclose($handle);
        }

        return $firstLine;
    }

    private function readFirstLine(): ?string
    {
        if (!file_exists($this->path)) {
            throw new IllegalStateException("File $this->path not exists");
        }

        $firstLine = fgets(fopen($this->path, 'rb'));

It seems like fopen($this->path, 'rb') can also be of type false; however, parameter $handle of fgets() does only seem to accept resource, maybe add an additional type check?

        return $firstLine ?: null;
    }
}