Introduce codec library

Author: alcaeus

psalm-baseline.xml

@@ -22,6 +22,16 @@
       <code>$mergedDriver['platform']</code>
     </MixedAssignment>
   </file>
+  <file src="src/Codec/DecodeIfSupported.php">
+    <MixedInferredReturnType occurrences="1">
+      <code>($value is BSONType ? NativeType : $value)</code>
+    </MixedInferredReturnType>
+  </file>
+  <file src="src/Codec/EncodeIfSupported.php">
+    <MixedInferredReturnType occurrences="1">
+      <code>($value is NativeType ? BSONType : $value)</code>
+    </MixedInferredReturnType>
+  </file>
   <file src="src/Command/ListCollections.php">
     <MixedAssignment occurrences="2">
       <code>$cmd[$option]</code>

src/Codec/CodecLibrary.php

@@ -0,0 +1,134 @@
+<?php
+
+namespace MongoDB\Codec;
+
+use MongoDB\Exception\InvalidArgumentException;
+use MongoDB\Exception\UnexpectedValueException;
+
+use function get_debug_type;
+use function sprintf;
+
+class CodecLibrary implements Codec
+{
+    use DecodeIfSupported;
+    use EncodeIfSupported;
+
+    /** @var array<Decoder> */
+    private $decoders = [];
+
+    /** @var array<Encoder> */
+    private $encoders = [];
+
+    /** @param Decoder|Encoder $items */
+    public function __construct(...$items)
+    {
+        foreach ($items as $item) {
+            if (! $item instanceof Decoder && ! $item instanceof Encoder) {
+                throw InvalidArgumentException::invalidType('$items', $item, [Decoder::class, Encoder::class]);
+            }
+
+            if ($item instanceof Codec) {
+                // Use attachCodec to avoid multiple calls to attachLibrary
+                $this->attachCodec($item);
+
+                continue;
+            }
+
+            if ($item instanceof Decoder) {
+                $this->attachDecoder($item);
+            }
+
+            if ($item instanceof Encoder) {
+                $this->attachEncoder($item);
+            }
+        }
+    }
+
+    /** @return static */
+    final public function attachCodec(Codec $codec): self
+    {
+        $this->decoders[] = $codec;
+        $this->encoders[] = $codec;
+        if ($codec instanceof KnowsCodecLibrary) {
+            $codec->attachLibrary($this);
+        }
+
+        return $this;
+    }
+
+    /** @return static */
+    final public function attachDecoder(Decoder $decoder): self
+    {
+        $this->decoders[] = $decoder;
+        if ($decoder instanceof KnowsCodecLibrary) {
+            $decoder->attachLibrary($this);
+        }
+
+        return $this;
+    }
+
+    /** @return static */
+    final public function attachEncoder(Encoder $encoder): self
+    {
+        $this->encoders[] = $encoder;
+        if ($encoder instanceof KnowsCodecLibrary) {
+            $encoder->attachLibrary($this);
+        }
+
+        return $this;
+    }
+
+    /** @param mixed $value */
+    final public function canDecode($value): bool
+    {
+        foreach ($this->decoders as $decoder) {
+            if ($decoder->canDecode($value)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /** @param mixed $value */
+    final public function canEncode($value): bool
+    {
+        foreach ($this->encoders as $encoder) {
+            if ($encoder->canEncode($value)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * @param mixed $value
+     * @return mixed
+     */
+    final public function decode($value)
+    {
+        foreach ($this->decoders as $decoder) {
+            if ($decoder->canDecode($value)) {
+                return $decoder->decode($value);
+            }
+        }
+
+        throw new UnexpectedValueException(sprintf('No decoder found for value of type "%s"', get_debug_type($value)));
+    }
+
+    /**
+     * @param mixed $value
+     * @return mixed
+     */
+    final public function encode($value)
+    {
+        foreach ($this->encoders as $encoder) {
+            if ($encoder->canEncode($value)) {
+                return $encoder->encode($value);
+            }
+        }
+
+        throw new UnexpectedValueException(sprintf('No encoder found for value of type "%s"', get_debug_type($value)));
+    }
+}

src/Codec/DecodeIfSupported.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace MongoDB\Codec;
+
+/**
+ * @psalm-template BSONType
+ * @psalm-template NativeType
+ */
+trait DecodeIfSupported
+{
+    /**
+     * @param mixed $value
+     * @psalm-assert-if-true BSONType $value
+     */
+    abstract public function canDecode($value): bool;
+
+    /**
+     * @param mixed $value
+     * @psalm-param BSONType $value
+     * @return mixed
+     * @psalm-return NativeType
+     */
+    abstract public function decode($value);
+
+    /**
+     * @param mixed $value
+     * @psalm-param mixed $value
+     * @return mixed
+     * @psalm-return ($value is BSONType ? NativeType : $value)
+     */
+    public function decodeIfSupported($value)
+    {
+        return $this->canDecode($value) ? $this->decode($value) : $value;
+    }
+}

src/Codec/EncodeIfSupported.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace MongoDB\Codec;
+
+/**
+ * @psalm-template BSONType
+ * @psalm-template NativeType
+ */
+trait EncodeIfSupported
+{
+    /**
+     * @param mixed $value
+     * @psalm-assert-if-true NativeType $value
+     */
+    abstract public function canEncode($value): bool;
+
+    /**
+     * @param mixed $value
+     * @psalm-param NativeType $value
+     * @return mixed
+     * @psalm-return BSONType
+     */
+    abstract public function encode($value);
+
+    /**
+     * @param mixed $value
+     * @psalm-param mixed $value
+     * @return mixed
+     * @psalm-return ($value is NativeType ? BSONType : $value)
+     */
+    public function encodeIfSupported($value)
+    {
+        return $this->canEncode($value) ? $this->encode($value) : $value;
+    }
+}

src/Codec/KnowsCodecLibrary.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace MongoDB\Codec;
+
+interface KnowsCodecLibrary
+{
+    public function attachLibrary(CodecLibrary $library): void;
+}