feat: do not preload hidden files and files in hidden folders

Refs: #682

greenmail-core/src/main/java/com/icegreen/greenmail/util/GreenMail.java

@@ -348,7 +348,7 @@ public GreenMailOperations loadEmails(Path sourceDirectory) throws IOException,
 
         try (final Stream<Path> pathStream = Files.walk(sourceDirectory)) {
             for (Path emailPath : pathStream
-                .filter(path -> !path.equals(sourceDirectory)) // Skip base dir
+                .filter(path -> !path.equals(sourceDirectory) && !isHiddenOrInHiddenDir(path)) // Skip base dir and files which are hidden or in hidden dirs
                 .map(Path::toAbsolutePath)
                 .collect(Collectors.toList())) {
                 loadEmail(sourceDirectory, emailPath, sourceNameCount, userManager, store, imapHostManager, session);
@@ -379,15 +379,16 @@ private void loadEmail(Path sourceDirectory, Path emailPath, int sourceNameCount
         }
 
         // Extract and optionally create intermediate folders
-        MailFolder folder = null;
-        folder = store.getMailbox(getUserBaseMailboxName(imapHostManager, user));
-        for (int i = sourceNameCount + 1; i < emailPathNameCount - 1; i++) {
-            String namePart = emailPath.getName(i).toString();
-            MailFolder child = store.getMailbox(folder, namePart);
-            if (null == child) {
-                child = store.createMailbox(folder, namePart, true);
+        MailFolder folder = store.getMailbox(getUserBaseMailboxName(imapHostManager, user));;
+        for (int i = sourceNameCount + 1; i < emailPathNameCount; i++) {
+            if (i < emailPathNameCount - 1 || Files.isDirectory(emailPath)) {
+                String namePart = emailPath.getName(i).toString();
+                MailFolder child = store.getMailbox(folder, namePart);
+                if (null == child) {
+                    child = store.createMailbox(folder, namePart, true);
+                }
+                folder = child;
             }
-            folder = child;
         }
 
         if (Files.isRegularFile(emailPath) && emailPath.toString().endsWith(".eml")) {
@@ -410,4 +411,12 @@ private String getUserBaseMailboxName(ImapHostManager imapHostManager, GreenMail
         }
         return inbox.substring(0, inbox.length() - ImapConstants.INBOX_NAME.length());
     }
+
+    private boolean isHiddenOrInHiddenDir(Path path) {
+        try {
+            return Files.isHidden(path) || (path.getParent() != null && isHiddenOrInHiddenDir(path.getParent()));
+        } catch (IOException e) {
+            throw new IllegalStateException("Failed during preloading '" + path + "'");
+        }
+    }
 }

greenmail-core/src/test/resources/preload/bar@localhost/INBOX/.hidden/test-5.eml

@@ -0,0 +1,11 @@
+Date: Sat, 16 Sep 2023 17:10:44 +0200 (CEST)
+From: bar@localhost
+To: foo@localhost
+Message-ID: <1882145060.266.1694877044545@127.0.0.1>
+Subject: test-5
+MIME-Version: 1.0
+Content-Type: text/plain; charset=us-ascii
+Content-Transfer-Encoding: 7bit
+
+Test message saved as eml (electronic mail format, aka internet message format)
+File is in hidden folder, so it should not be preloaded

greenmail-core/src/test/resources/preload/bar@localhost/INBOX/.test-5.eml

@@ -0,0 +1,11 @@
+Date: Sat, 16 Sep 2023 17:10:44 +0200 (CEST)
+From: bar@localhost
+To: foo@localhost
+Message-ID: <1882145060.266.1694877044545@127.0.0.1>
+Subject: test-5
+MIME-Version: 1.0
+Content-Type: text/plain; charset=us-ascii
+Content-Transfer-Encoding: 7bit
+
+Test message saved as eml (electronic mail format, aka internet message format).
+File is hidden, so it should not be preloaded

pom.xml

@@ -349,6 +349,17 @@
           </execution>
         </executions>
       </plugin>
+      <plugin>
+        <artifactId>maven-resources-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>default-testResources</id>
+            <configuration>
+              <includeEmptyDirs>true</includeEmptyDirs>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
 
   </build>