Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-content/plugins/contact-form-7/includes/swv/rules/requiredfile.php

@@ -0,0 +1,37 @@
+<?php
+
+class WPCF7_SWV_RequiredFileRule extends WPCF7_SWV_Rule {
+
+	const rule_name = 'requiredfile';
+
+	public function matches( $context ) {
+		if ( false === parent::matches( $context ) ) {
+			return false;
+		}
+
+		if ( empty( $context['file'] ) ) {
+			return false;
+		}
+
+		return true;
+	}
+
+	public function validate( $context ) {
+		$field = $this->get_property( 'field' );
+
+		$input = isset( $_FILES[$field]['tmp_name'] )
+			? $_FILES[$field]['tmp_name'] : '';
+
+		$input = wpcf7_array_flatten( $input );
+		$input = wpcf7_exclude_blank( $input );
+
+		if ( empty( $input ) ) {
+			return new WP_Error( 'wpcf7_invalid_requiredfile',
+				$this->get_property( 'error' )
+			);
+		}
+
+		return true;
+	}
+
+}