initial commit

pma/libraries/classes/Query/Cache.php

@@ -0,0 +1,97 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpMyAdmin\Query;
+
+use PhpMyAdmin\Util;
+
+use function array_shift;
+use function count;
+use function is_array;
+
+/**
+ * Handles caching results
+ */
+class Cache
+{
+    /** @var array[] Table data cache */
+    private $tableCache = [];
+
+    /**
+     * Caches table data so Table does not require to issue
+     * SHOW TABLE STATUS again
+     *
+     * @param mixed[][] $tables information for tables of some databases
+     */
+    public function cacheTableData(string $database, array $tables): void
+    {
+        // Note: This function must not use array_merge because numerical indices must be preserved.
+        // When an entry already exists for the database in cache, we merge the incoming data with existing data.
+        // The union operator appends elements from right to left unless they exists on the left already.
+        // Doing the union with incoming data on the left ensures that when we reread table status from DB,
+        // we overwrite whatever was in cache with the new data.
+
+        if (isset($this->tableCache[$database])) {
+            $this->tableCache[$database] = $tables + $this->tableCache[$database];
+        } else {
+            $this->tableCache[$database] = $tables;
+        }
+    }
+
+    /**
+     * Set an item in table cache using dot notation.
+     *
+     * @param array|null $contentPath Array with the target path
+     * @param mixed      $value       Target value
+     */
+    public function cacheTableContent(?array $contentPath, $value): void
+    {
+        $loc = &$this->tableCache;
+
+        if (! isset($contentPath)) {
+            $loc = $value;
+
+            return;
+        }
+
+        while (count($contentPath) > 1) {
+            $key = array_shift($contentPath);
+
+            // If the key doesn't exist at this depth, we will just create an empty
+            // array to hold the next value, allowing us to create the arrays to hold
+            // final values at the correct depth. Then we'll keep digging into the
+            // array.
+            if (! isset($loc[$key]) || ! is_array($loc[$key])) {
+                $loc[$key] = [];
+            }
+
+            $loc = &$loc[$key];
+        }
+
+        $loc[array_shift($contentPath)] = $value;
+    }
+
+    /**
+     * Get a cached value from table cache.
+     *
+     * @param array $contentPath Array of the name of the target value
+     * @param mixed $default     Return value on cache miss
+     *
+     * @return mixed cached value or default
+     */
+    public function getCachedTableContent(array $contentPath, $default = null)
+    {
+        return Util::getValueByKey($this->tableCache, $contentPath, $default);
+    }
+
+    public function getCache(): array
+    {
+        return $this->tableCache;
+    }
+
+    public function clearTableCache(): void
+    {
+        $this->tableCache = [];
+    }
+}