[Serializer] Added a ChainEncoder and a ChainDecoder

These classes contains the logic previously defined in the Serializer
itself to handle the choice of a serializer. This allows reusing it when
using only the encoding part of the component.

src/Symfony/Component/Serializer/Encoder/ChainDecoder.php

@@ -0,0 +1,82 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Encoder;
+
+use Symfony\Component\Serializer\Encoder\DecoderInterface;
+use Symfony\Component\Serializer\Exception\RuntimeException;
+
+/**
+ * Decoder delegating the decoding to a chain of decoders.
+ *
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ * @author Lukas Kahwe Smith <smith@pooteeweet.org>
+ */
+class ChainDecoder implements DecoderInterface
+{
+    protected $decoders = array();
+    protected $decoderByFormat = array();
+
+    public function __construct(array $decoders = array())
+    {
+        $this->decoders = $decoders;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    final public function decode($data, $format)
+    {
+        return $this->getDecoder($format)->decode($data, $format);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsDecoding($format)
+    {
+        try {
+            $this->getDecoder($format);
+        } catch (RuntimeException $e) {
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Gets the decoder supporting the format.
+     *
+     * @param string $format
+     *
+     * @return DecoderInterface
+     * @throws RuntimeException if no decoder is found
+     */
+    private function getDecoder($format)
+    {
+        if (isset($this->decoderByFormat[$format])
+            && isset($this->decoders[$this->decoderByFormat[$format]])
+        ) {
+            return $this->decoders[$this->decoderByFormat[$format]];
+        }
+
+        foreach ($this->decoders as $i => $decoder) {
+            if ($decoder->supportsDecoding($format)) {
+                $this->decoderByFormat[$format] = $i;
+
+                return $decoder;
+            }
+        }
+
+        throw new RuntimeException(sprintf('No decoder found for format "%s".', $format));
+    }
+}

src/Symfony/Component/Serializer/Encoder/ChainEncoder.php

@@ -0,0 +1,82 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Serializer\Encoder;
+
+use Symfony\Component\Serializer\Encoder\EncoderInterface;
+use Symfony\Component\Serializer\Exception\RuntimeException;
+
+/**
+ * Encoder delegating the decoding to a chain of encoders.
+ *
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ * @author Lukas Kahwe Smith <smith@pooteeweet.org>
+ */
+class ChainEncoder implements EncoderInterface
+{
+    protected $encoders = array();
+    protected $encoderByFormat = array();
+
+    public function __construct(array $encoders = array())
+    {
+        $this->encoders = $encoders;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    final public function encode($data, $format)
+    {
+        return $this->getEncoder($format)->encode($data, $format);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsEncoding($format)
+    {
+        try {
+            $this->getEncoder($format);
+        } catch (RuntimeException $e) {
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Gets the encoder supporting the format.
+     *
+     * @param string $format
+     *
+     * @return EncoderInterface
+     * @throws RuntimeException if no encoder is found
+     */
+    public function getEncoder($format)
+    {
+        if (isset($this->encoderByFormat[$format])
+            && isset($this->encoders[$this->encoderByFormat[$format]])
+        ) {
+            return $this->encoders[$this->encoderByFormat[$format]];
+        }
+
+        foreach ($this->encoders as $i => $encoder) {
+            if ($encoder->supportsEncoding($format)) {
+                $this->encoderByFormat[$format] = $i;
+
+                return $encoder;
+            }
+        }
+
+        throw new RuntimeException(sprintf('No encoder found for format "%s".', $format));
+    }
+}

src/Symfony/Component/Serializer/Serializer.php

@@ -11,6 +11,8 @@
 
 namespace Symfony\Component\Serializer;
 
+use Symfony\Component\Serializer\Encoder\ChainDecoder;
+use Symfony\Component\Serializer\Encoder\ChainEncoder;
 use Symfony\Component\Serializer\Encoder\EncoderInterface;
 use Symfony\Component\Serializer\Encoder\DecoderInterface;
 use Symfony\Component\Serializer\Encoder\NormalizationAwareInterface;
@@ -36,6 +38,8 @@ use Symfony\Component\Serializer\Exception\UnexpectedValueException;
  */
 class Serializer implements SerializerInterface, NormalizerInterface, DenormalizerInterface, EncoderInterface, DecoderInterface
 {
+    protected $encoder;
+    protected $decoder;
     protected $normalizers = array();
     protected $encoders = array();
     protected $normalizerCache = array();
@@ -52,12 +56,21 @@ class Serializer implements SerializerInterface, NormalizerInterface, Denormaliz
         }
         $this->normalizers = $normalizers;
 
+        $decoders = array();
+        $realEncoders = array();
         foreach ($encoders as $encoder) {
             if ($encoder instanceof SerializerAwareInterface) {
                 $encoder->setSerializer($this);
             }
+            if ($encoder instanceof DecoderInterface) {
+                $decoders[] = $encoder;
+            }
+            if ($encoder instanceof EncoderInterface) {
+                $realEncoders[] = $encoder;
+            }
         }
-        $this->encoders = $encoders;
+        $this->encoder = new ChainEncoder($realEncoders);
+        $this->decoder = new ChainDecoder($decoders);
     }
 
     /**
@@ -69,7 +82,7 @@ class Serializer implements SerializerInterface, NormalizerInterface, Denormaliz
             throw new UnexpectedValueException('Serialization for the format '.$format.' is not supported');
         }
 
-        $encoder = $this->getEncoder($format);
+        $encoder = $this->encoder->getEncoder($format);
 
         if (!$encoder instanceof NormalizationAwareInterface) {
             $data = $this->normalize($data, $format);
@@ -197,7 +210,7 @@ class Serializer implements SerializerInterface, NormalizerInterface, Denormaliz
      */
     final public function encode($data, $format)
     {
-        return $this->getEncoder($format)->encode($data, $format);
+        return $this->encoder->encode($data, $format);
     }
 
     /**
@@ -205,7 +218,7 @@ class Serializer implements SerializerInterface, NormalizerInterface, Denormaliz
      */
     final public function decode($data, $format)
     {
-        return $this->getEncoder($format)->decode($data, $format);
+        return $this->decoder->decode($data, $format);
     }
 
     /**
@@ -271,13 +284,7 @@ class Serializer implements SerializerInterface, NormalizerInterface, Denormaliz
      */
     public function supportsEncoding($format)
     {
-        try {
-            $this->getEncoder($format);
-        } catch (RuntimeException $e) {
-            return false;
-        }
-
-        return true;
+        return $this->encoder->supportsEncoding($format);
     }
 
     /**
@@ -285,60 +292,6 @@ class Serializer implements SerializerInterface, NormalizerInterface, Denormaliz
      */
     public function supportsDecoding($format)
     {
-        try {
-            $this->getDecoder($format);
-        } catch (RuntimeException $e) {
-            return false;
-        }
-
-        return true;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    private function getEncoder($format)
-    {
-        if (isset($this->encoderByFormat[$format])
-            && isset($this->encoders[$this->encoderByFormat[$format]])
-        ) {
-            return $this->encoders[$this->encoderByFormat[$format]];
-        }
-
-        foreach ($this->encoders as $i => $encoder) {
-            if ($encoder instanceof EncoderInterface
-                && $encoder->supportsEncoding($format)
-            ) {
-                $this->encoderByFormat[$format] = $i;
-
-                return $encoder;
-            }
-        }
-
-        throw new RuntimeException(sprintf('No encoder found for format "%s".', $format));
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    private function getDecoder($format)
-    {
-        if (isset($this->decoderByFormat[$format])
-            && isset($this->encoders[$this->decoderByFormat[$format]])
-        ) {
-            return $this->encoders[$this->decoderByFormat[$format]];
-        }
-
-        foreach ($this->encoders as $i => $encoder) {
-            if ($encoder instanceof DecoderInterface
-                && $encoder->supportsDecoding($format)
-            ) {
-                $this->decoderByFormat[$format] = $i;
-
-                return $encoder;
-            }
-        }
-
-        throw new RuntimeException(sprintf('No decoder found for format "%s".', $format));
+        return $this->decoder->supportsDecoding($format);
     }
 }