Initial SQLite development (#1)

Reviewed-on: #1

src/Mapper/DocumentMapper.php

@@ -0,0 +1,44 @@
+<?php declare(strict_types=1);
+
+namespace BitBadger\PDODocument\Mapper;
+
+use BitBadger\PDODocument\DocumentException;
+use JsonMapper;
+use JsonMapper_Exception;
+
+/**
+ * Map domain class instances from JSON documents
+ *
+ * @template TDoc The type of document returned by this mapper
+ * @implements Mapper<TDoc> Provide a mapping from JSON
+ */
+class DocumentMapper implements Mapper
+{
+    /**
+     * Constructor
+     *
+     * @param class-string<TDoc> $className The type of class to be returned by this mapping
+     * @param string $fieldName The name of the field (optional; defaults to `data`)
+     */
+    public function __construct(public string $className, public string $fieldName = 'data') { }
+
+    /**
+     * Map a result to a domain class instance
+     *
+     * @param array $result An associative array representing a single database result
+     * @return TDoc The document, deserialized from its JSON representation
+     * @throws DocumentException If the JSON cannot be deserialized
+     */
+    public function map(array $result): mixed
+    {
+        try {
+            $json = json_decode($result[$this->fieldName]);
+            if (is_null($json)) {
+                throw new DocumentException("Could not map document for $this->className: " . json_last_error_msg());
+            }
+            return (new JsonMapper())->map($json, $this->className);
+        } catch (JsonMapper_Exception $ex) {
+            throw new DocumentException("Could not map document for $this->className", previous: $ex);
+        }
+    }
+}