Refactor StreamTrait functionality into Stream.php

Following on from the advice of @lcobucci, this change refactors the
StreamTrait functionality into Stream, and removes the trait from both
Stream and StreamFactory. On thinking about it, it makes most sense to
have this functionality directly in Stream, and not, in effect,
duplicated in multiple locations by another form.

Signed-off-by: Matthew Setter <matthew@matthewsetter.com>

src/Stream.php

@@ -40,7 +40,10 @@
  */
 class Stream implements StreamInterface
 {
-    use StreamTrait;
+    /**
+     * A list of allowed stream resource types that are allowed to instantiate a Stream
+     */
+    private const ALLOWED_STREAM_RESOURCE_TYPES = ['gd', 'stream'];
 
     /**
      * @var resource|null
@@ -359,4 +362,17 @@ private function setStream($stream, string $mode = 'r') : void
 
         $this->resource = $resource;
     }
+
+    /**
+     * Determine if a resource is one of the resource types allowed to instantiate a Stream
+     *
+     * @param resource $resource Stream resource.
+     */
+    private function isValidStreamResourceType($resource): bool
+    {
+        return (
+            is_resource($resource) &&
+            in_array(get_resource_type($resource), self::ALLOWED_STREAM_RESOURCE_TYPES, true)
+        );
+    }
 }

src/StreamFactory.php

@@ -21,7 +21,6 @@
 
 class StreamFactory implements StreamFactoryInterface
 {
-    use StreamTrait;
 
     /**
      * {@inheritDoc}
@@ -48,11 +47,6 @@ public function createStreamFromFile(string $file, string $mode = 'r') : StreamI
      */
     public function createStreamFromResource($resource) : StreamInterface
     {
-        if (! $this->isValidStreamResourceType($resource)) {
-            throw new Exception\InvalidArgumentException(
-                'Invalid stream provided; must be a stream resource'
-            );
-        }
         return new Stream($resource);
     }
 }