Add new optional beta email parser thats based on ImapEngine instead of Webklex

plugins/vendor/zbateson/mail-mime-parser/src/Header/Consumer/SubjectConsumerService.php

@@ -0,0 +1,62 @@
+<?php
+/**
+ * This file is part of the ZBateson\MailMimeParser project.
+ *
+ * @license http://opensource.org/licenses/bsd-license.php BSD
+ */
+
+namespace ZBateson\MailMimeParser\Header\Consumer;
+
+use Iterator;
+use Psr\Log\LoggerInterface;
+use ZBateson\MailMimeParser\Header\IHeaderPart;
+use ZBateson\MailMimeParser\Header\Part\MimeToken;
+use ZBateson\MailMimeParser\Header\Part\MimeTokenPartFactory;
+
+/**
+ * Extends AbstractGenericConsumerService to use a MimeTokenPartFactory, and
+ * to preserve all whitespace and escape sequences as-is (unlike other headers
+ * subject headers don't have escape chars such as '\\' for a backslash).
+ *
+ * SubjectConsumerService doesn't define any sub-consumers.
+ *
+ * @author Zaahid Bateson
+ */
+class SubjectConsumerService extends AbstractGenericConsumerService
+{
+    public function __construct(LoggerInterface $logger, MimeTokenPartFactory $partFactory)
+    {
+        parent::__construct($logger, $partFactory);
+    }
+
+    /**
+     * Overridden to preserve whitespace.
+     *
+     * Whitespace between two words is preserved unless the whitespace begins
+     * with a newline (\n or \r\n), in which case the entire string of
+     * whitespace is discarded, and a single space ' ' character is used in its
+     * place.
+     */
+    protected function getPartForToken(string $token, bool $isLiteral) : ?IHeaderPart
+    {
+        if (\preg_match('/' . MimeToken::MIME_PART_PATTERN . '/', $token)) {
+            return $this->partFactory->newMimeToken($token);
+        }
+        return $this->partFactory->newSubjectToken($token);
+    }
+
+    /**
+     * Returns an array of \ZBateson\MailMimeParser\Header\Part\HeaderPart for
+     * the current token on the iterator.
+     *
+     * Overridden from AbstractConsumerService to remove special filtering for
+     * backslash escaping, which also seems to not apply to Subject headers at
+     * least in ThunderBird's implementation.
+     *
+     * @return IHeaderPart[]
+     */
+    protected function getTokenParts(Iterator $tokens) : array
+    {
+        return $this->getConsumerTokenParts($tokens);
+    }
+}