1<?php
2
3declare(strict_types=1);
4
5namespace PhpMyAdmin\Query;
6
7use PhpMyAdmin\Util;
8use function array_shift;
9use function count;
10use function is_array;
11
12/**
13 * Handles caching results
14 */
15class Cache
16{
17    /** @var array Table data cache */
18    private $tableCache = [];
19
20    /**
21     * Caches table data so Table does not require to issue
22     * SHOW TABLE STATUS again
23     *
24     * @param array       $tables information for tables of some databases
25     * @param string|bool $table  table name
26     */
27    public function cacheTableData(array $tables, $table): void
28    {
29        // Note: I don't see why we would need array_merge_recursive() here,
30        // as it creates double entries for the same table (for example a double
31        // entry for Comment when changing the storage engine in Operations)
32        // Note 2: Instead of array_merge(), simply use the + operator because
33        //  array_merge() renumbers numeric keys starting with 0, therefore
34        //  we would lose a db name that consists only of numbers
35
36        foreach ($tables as $one_database => $_) {
37            if (isset($this->tableCache[$one_database])) {
38                // the + operator does not do the intended effect
39                // when the cache for one table already exists
40                if ($table
41                    && isset($this->tableCache[$one_database][$table])
42                ) {
43                    unset($this->tableCache[$one_database][$table]);
44                }
45                $this->tableCache[$one_database]
46                    += $tables[$one_database];
47            } else {
48                $this->tableCache[$one_database] = $tables[$one_database];
49            }
50        }
51    }
52
53    /**
54     * Set an item in table cache using dot notation.
55     *
56     * @param array|null $contentPath Array with the target path
57     * @param mixed      $value       Target value
58     */
59    public function cacheTableContent(?array $contentPath, $value): void
60    {
61        $loc = &$this->tableCache;
62
63        if (! isset($contentPath)) {
64            $loc = $value;
65
66            return;
67        }
68
69        while (count($contentPath) > 1) {
70            $key = array_shift($contentPath);
71
72            // If the key doesn't exist at this depth, we will just create an empty
73            // array to hold the next value, allowing us to create the arrays to hold
74            // final values at the correct depth. Then we'll keep digging into the
75            // array.
76            if (! isset($loc[$key]) || ! is_array($loc[$key])) {
77                $loc[$key] = [];
78            }
79            $loc = &$loc[$key];
80        }
81
82        $loc[array_shift($contentPath)] = $value;
83    }
84
85    /**
86     * Get a cached value from table cache.
87     *
88     * @param array $contentPath Array of the name of the target value
89     * @param mixed $default     Return value on cache miss
90     *
91     * @return mixed cached value or default
92     */
93    public function getCachedTableContent(array $contentPath, $default = null)
94    {
95        return Util::getValueByKey($this->tableCache, $contentPath, $default);
96    }
97
98    public function getCache(): array
99    {
100        return $this->tableCache;
101    }
102
103    public function clearTableCache(): void
104    {
105        $this->tableCache = [];
106    }
107}
108