runff 1.0 commit

lib/aws/JmesPath/AstRuntime.php

@@ -0,0 +1,47 @@
+<?php
+namespace JmesPath;
+
+/**
+ * Uses an external tree visitor to interpret an AST.
+ */
+class AstRuntime
+{
+    private $parser;
+    private $interpreter;
+    private $cache = [];
+    private $cachedCount = 0;
+
+    public function __construct(
+        Parser $parser = null,
+        callable $fnDispatcher = null
+    ) {
+        $fnDispatcher = $fnDispatcher ?: FnDispatcher::getInstance();
+        $this->interpreter = new TreeInterpreter($fnDispatcher);
+        $this->parser = $parser ?: new Parser();
+    }
+
+    /**
+     * Returns data from the provided input that matches a given JMESPath
+     * expression.
+     *
+     * @param string $expression JMESPath expression to evaluate
+     * @param mixed  $data       Data to search. This data should be data that
+     *                           is similar to data returned from json_decode
+     *                           using associative arrays rather than objects.
+     *
+     * @return mixed|null Returns the matching data or null
+     */
+    public function __invoke($expression, $data)
+    {
+        if (!isset($this->cache[$expression])) {
+            // Clear the AST cache when it hits 1024 entries
+            if (++$this->cachedCount > 1024) {
+                $this->cache = [];
+                $this->cachedCount = 0;
+            }
+            $this->cache[$expression] = $this->parser->parse($expression);
+        }
+
+        return $this->interpreter->visit($this->cache[$expression], $data);
+    }
+}