Antlr\Antlr4\Runtime\PredictionContexts\PredictionContextCache

Complexity

Total Complexity

6

Size/Duplication

Total Lines	40
Duplicated Lines	0 %

Test Coverage

Coverage

73.32%

Importance

Changes	1
Bugs	0	Features	0

4 Methods

Rating	Name	Duplication	Size	Complexity
A	length()	0	3	1
A	__construct()	0	3	1
A	get()	0	3	1
A	add()	0	15	3

<?php

declare(strict_types=1);

namespace Antlr\Antlr4\Runtime\PredictionContexts;

use Antlr\Antlr4\Runtime\Utils\Map;

/**
 * Used to cache {@see PredictionContext} objects. Its used for the shared
 * context cash associated with contexts in DFA states. This cache
 * can be used for both lexers and parsers.
 */
class PredictionContextCache
{
    /** @var Map */
    protected $cache;

    public function __construct()
    {
        $this->cache = new Map();
    }

    /**
     * Add a context to the cache and return it. If the context already exists,
     * return that one instead and do not add a new context to the cache.
     * Protect shared cache from unsafe thread access.
     */
    public function add(PredictionContext $ctx) : PredictionContext
    {
        if ($ctx === PredictionContext::empty()) {

The condition $ctx === Antlr\Antlr4\Runtime\PredictionContexts\PredictionContext::empty() is always false.

            return $ctx;
        }

        $existing = $this->cache->get($ctx);

        if ($existing !== null) {
            return $existing;
        }

        $this->cache->put($ctx, $ctx);

        return $ctx;
    }

    public function get(PredictionContext $ctx) : ?PredictionContext
    {
        return $this->cache->get($ctx);
    }

    public function length() : int
    {
        return $this->cache->count();
    }
}