PHPLIB-242: Create helper to apply field paths for type maps

src/functions.php

@@ -241,3 +241,46 @@ function recursive_copy($element) {
 
     return clone $element;
 }
+
+/**
+ * Creates a type map to apply to a field type
+ *
+ * This is used in the Aggregate, Distinct, and FindAndModify operations to
+ * apply the root-level type map to the document that will be returned. It also
+ * replaces the root type with object for consistency within these operations
+ *
+ * An existing type map for the given field path will not be overwritten
+ *
+ * @internal
+ * @param array  $typeMap   The existing typeMap
+ * @param string $fieldPath The field path to apply the root type to
+ * @return array
+ */
+function create_field_path_type_map(array $typeMap, $fieldPath)
+{
+    // If some field paths already exist, we prefix them with the field path we are assuming as the new root
+    if (isset($typeMap['fieldPaths']) && is_array($typeMap['fieldPaths'])) {
+        $fieldPaths = $typeMap['fieldPaths'];
+
+        $typeMap['fieldPaths'] = [];
+        foreach ($fieldPaths as $existingFieldPath => $type) {
+            $typeMap['fieldPaths'][$fieldPath . '.' . $existingFieldPath] = $type;
+        }
+    }
+
+    // If a root typemap was set, apply this to the field object
+    if (isset($typeMap['root'])) {
+        $typeMap['fieldPaths'][$fieldPath] = $typeMap['root'];
+    }
+
+    /* Special case if we want to convert an array, in which case we need to
+     * ensure that the field containing the array is exposed as an array,
+     * instead of the type given in the type map's array key. */
+    if (substr($fieldPath, -2, 2) === '.$') {
+        $typeMap['fieldPaths'][substr($fieldPath, 0, -2)] = 'array';
+    }
+
+    $typeMap['root'] = 'object';
+
+    return $typeMap;
+}

tests/FunctionsTest.php

@@ -135,4 +135,70 @@ class FunctionsTest extends TestCase
             [ ['replace' => 'collectionName'], false ],
         ];
     }
+
+    /**
+     * @dataProvider provideTypeMapValues
+     */
+    public function testCreateFieldPathTypeMap(array $expected, array $typeMap, $fieldPath = 'field')
+    {
+        $this->assertEquals($expected, \MongoDB\create_field_path_type_map($typeMap, $fieldPath));
+    }
+
+    public function provideTypeMapValues()
+    {
+        return [
+            'No root type' => [
+                ['document' => 'array', 'root' => 'object'],
+                ['document' => 'array'],
+            ],
+            'No field path' => [
+                ['root' => 'object', 'fieldPaths' => ['field' => 'array']],
+                ['root' => 'array'],
+            ],
+            'Field path exists' => [
+                ['root' => 'object', 'fieldPaths' => ['field' => 'array', 'field.field' => 'object']],
+                ['root' => 'array', 'fieldPaths' => ['field' => 'object']],
+            ],
+            'Nested field path' => [
+                ['root' => 'object', 'fieldPaths' => ['field' => 'object', 'field.nested' => 'array']],
+                ['root' => 'object', 'fieldPaths' => ['nested' => 'array']],
+            ],
+            'Array field path converted to array' => [
+                [
+                    'root' => 'object',
+                    'array' => 'MongoDB\Model\BSONArray',
+                    'fieldPaths' => [
+                        'field' => 'array',
+                        'field.$' => 'object',
+                        'field.$.nested' => 'array',
+                    ]
+                ],
+                [
+                    'root' => 'object',
+                    'array' => 'MongoDB\Model\BSONArray',
+                    'fieldPaths' => [
+                        'nested' => 'array',
+                    ]
+                ],
+                'field.$',
+            ],
+            'Array field path without root key' => [
+                [
+                    'root' => 'object',
+                    'array' => 'MongoDB\Model\BSONArray',
+                    'fieldPaths' => [
+                        'field' => 'array',
+                        'field.$.nested' => 'array',
+                    ]
+                ],
+                [
+                    'array' => 'MongoDB\Model\BSONArray',
+                    'fieldPaths' => [
+                        'nested' => 'array',
+                    ]
+                ],
+                'field.$',
+            ],
+        ];
+    }
 }