v2: Updates

* Simplifies & beautifies everything
* Introduces a new Class system.
* Errors are defaulted to AWS's handler.
* New function names & more efficient handling.
* Should fix a majority of the errors.

Please read the README for more!

aws/Aws/S3/Crypto/CryptoParamsTrait.php

@@ -0,0 +1,75 @@
+<?php
+namespace Aws\S3\Crypto;
+
+use Aws\Crypto\MaterialsProvider;
+use Aws\Crypto\MetadataEnvelope;
+use Aws\Crypto\MetadataStrategyInterface;
+
+trait CryptoParamsTrait
+{
+    protected function getMaterialsProvider(array $args)
+    {
+        if ($args['@MaterialsProvider'] instanceof MaterialsProvider) {
+            return $args['@MaterialsProvider'];
+        }
+
+        throw new \InvalidArgumentException('An instance of MaterialsProvider'
+            . ' must be passed in the "MaterialsProvider" field.');
+    }
+
+    protected function getInstructionFileSuffix(array $args)
+    {
+        return !empty($args['@InstructionFileSuffix'])
+            ? $args['@InstructionFileSuffix']
+            : $this->instructionFileSuffix;
+    }
+
+    protected function determineGetObjectStrategy(
+        $result,
+        $instructionFileSuffix
+    ) {
+        if (isset($result['Metadata'][MetadataEnvelope::CONTENT_KEY_V2_HEADER])) {
+            return new HeadersMetadataStrategy();
+        }
+
+        return new InstructionFileMetadataStrategy(
+            $this->client,
+            $instructionFileSuffix
+        );
+    }
+
+    protected function getMetadataStrategy(array $args, $instructionFileSuffix)
+    {
+        if (!empty($args['@MetadataStrategy'])) {
+            if ($args['@MetadataStrategy'] instanceof MetadataStrategyInterface) {
+                return $args['@MetadataStrategy'];
+            }
+
+            if (is_string($args['@MetadataStrategy'])) {
+                switch ($args['@MetadataStrategy']) {
+                    case HeadersMetadataStrategy::class:
+                        return new HeadersMetadataStrategy();
+                    case InstructionFileMetadataStrategy::class:
+                        return new InstructionFileMetadataStrategy(
+                            $this->client,
+                            $instructionFileSuffix
+                        );
+                    default:
+                        throw new \InvalidArgumentException('Could not match the'
+                            . ' specified string in "MetadataStrategy" to a'
+                            . ' predefined strategy.');
+                }
+            } else {
+                throw new \InvalidArgumentException('The metadata strategy that'
+                    . ' was passed to "MetadataStrategy" was unrecognized.');
+            }
+        } elseif ($instructionFileSuffix) {
+            return new InstructionFileMetadataStrategy(
+                $this->client,
+                $instructionFileSuffix
+            );
+        }
+
+        return null;
+    }
+}