1 files changed, 207 insertions, 0 deletions
diff --git a/inc/mailgun/php-http/discovery/src/ClassDiscovery.php b/inc/mailgun/php-http/discovery/src/ClassDiscovery.php
new file mode 100644
index 0000000..2c3e877
--- /dev/null
+++ b/inc/mailgun/php-http/discovery/src/ClassDiscovery.php
@@ -0,0 +1,207 @@
+<?php
+
+namespace Http\Discovery;
+
+use Http\Discovery\Exception\ClassInstantiationFailedException;
+use Http\Discovery\Exception\DiscoveryFailedException;
+use Http\Discovery\Exception\StrategyUnavailableException;
+
+/**
+ * Registry that based find results on class existence.
+ *
+ * @author David de Boer <david@ddeboer.nl>
+ * @author Márk Sági-Kazár <mark.sagikazar@gmail.com>
+ * @author Tobias Nyholm <tobias.nyholm@gmail.com>
+ */
+abstract class ClassDiscovery
+{
+    /**
+     * A list of strategies to find classes.
+     *
+     * @var array
+     */
+    private static $strategies = [
+        Strategy\PuliBetaStrategy::class,
+        Strategy\CommonClassesStrategy::class,
+    ];
+
+    /**
+     * Discovery cache to make the second time we use discovery faster.
+     *
+     * @var array
+     */
+    private static $cache = [];
+
+    /**
+     * Finds a class.
+     *
+     * @param string $type
+     *
+     * @return string|\Closure
+     *
+     * @throws DiscoveryFailedException
+     */
+    protected static function findOneByType($type)
+    {
+        // Look in the cache
+        if (null !== ($class = self::getFromCache($type))) {
+            return $class;
+        }
+
+        $exceptions = [];
+        foreach (self::$strategies as $strategy) {
+            try {
+                $candidates = call_user_func($strategy.'::getCandidates', $type);
+            } catch (StrategyUnavailableException $e) {
+                $exceptions[] = $e;
+                continue;
+            }
+
+            foreach ($candidates as $candidate) {
+                if (isset($candidate['condition'])) {
+                    if (!self::evaluateCondition($candidate['condition'])) {
+                        continue;
+                    }
+                }
+
+                // save the result for later use
+                self::storeInCache($type, $candidate);
+
+                return $candidate['class'];
+            }
+        }
+
+        throw DiscoveryFailedException::create($exceptions);
+    }
+
+    /**
+     * Get a value from cache.
+     *
+     * @param string $type
+     *
+     * @return string|null
+     */
+    private static function getFromCache($type)
+    {
+        if (!isset(self::$cache[$type])) {
+            return;
+        }
+
+        $candidate = self::$cache[$type];
+        if (isset($candidate['condition'])) {
+            if (!self::evaluateCondition($candidate['condition'])) {
+                return;
+            }
+        }
+
+        return $candidate['class'];
+    }
+
+    /**
+     * Store a value in cache.
+     *
+     * @param string $type
+     * @param string $class
+     */
+    private static function storeInCache($type, $class)
+    {
+        self::$cache[$type] = $class;
+    }
+
+    /**
+     * Set new strategies and clear the cache.
+     *
+     * @param array $strategies string array of fully qualified class name to a DiscoveryStrategy
+     */
+    public static function setStrategies(array $strategies)
+    {
+        self::$strategies = $strategies;
+        self::clearCache();
+    }
+
+    /**
+     * Append a strategy at the end of the strategy queue.
+     *
+     * @param string $strategy Fully qualified class name to a DiscoveryStrategy
+     */
+    public static function appendStrategy($strategy)
+    {
+        self::$strategies[] = $strategy;
+        self::clearCache();
+    }
+
+    /**
+     * Prepend a strategy at the beginning of the strategy queue.
+     *
+     * @param string $strategy Fully qualified class name to a DiscoveryStrategy
+     */
+    public static function prependStrategy($strategy)
+    {
+        array_unshift(self::$strategies, $strategy);
+        self::clearCache();
+    }
+
+    /**
+     * Clear the cache.
+     */
+    public static function clearCache()
+    {
+        self::$cache = [];
+    }
+
+    /**
+     * Evaluates conditions to boolean.
+     *
+     * @param mixed $condition
+     *
+     * @return bool
+     */
+    protected static function evaluateCondition($condition)
+    {
+        if (is_string($condition)) {
+            // Should be extended for functions, extensions???
+            return class_exists($condition);
+        } elseif (is_callable($condition)) {
+            return $condition();
+        } elseif (is_bool($condition)) {
+            return $condition;
+        } elseif (is_array($condition)) {
+            $evaluatedCondition = true;
+
+            // Immediately stop execution if the condition is false
+            for ($i = 0; $i < count($condition) && false !== $evaluatedCondition; ++$i) {
+                $evaluatedCondition &= static::evaluateCondition($condition[$i]);
+            }
+
+            return $evaluatedCondition;
+        }
+
+        return false;
+    }
+
+    /**
+     * Get an instance of the $class.
+     *
+     * @param string|\Closure $class A FQCN of a class or a closure that instantiate the class.
+     *
+     * @return object
+     *
+     * @throws ClassInstantiationFailedException
+     */
+    protected static function instantiateClass($class)
+    {
+        try {
+            if (is_string($class)) {
+                return new $class();
+            }
+
+            if (is_callable($class)) {
+                return $class();
+            }
+        } catch (\Exception $e) {
+            throw new ClassInstantiationFailedException('Unexpected exception when instantiating class.', 0, $e);
+        }
+
+        throw new ClassInstantiationFailedException('Could not instantiate class because parameter is neither a callable nor a string');
+    }
+}