Add spam filtering capability to MessagingController

src/com/fsck/k9/K9.java

@@ -294,6 +294,8 @@ public class K9 extends Application {
 
     public static final String IDENTITY_HEADER = "X-K9mail-Identity";
 
+    public static final String SPAM_FLAG_HEADER = "X-Spam-Flag";
+
     /**
      * Specifies how many messages will be shown in a folder by default. This number is set
      * on each new folder and can be incremented with "Load more messages..." by the

src/com/fsck/k9/controller/MessagingController.java

@@ -1256,6 +1256,7 @@ public class MessagingController implements Runnable {
         messages.clear();
         final ArrayList<Message> largeMessages = new ArrayList<Message>();
         final ArrayList<Message> smallMessages = new ArrayList<Message>();
+        final Map<String, String> spamMessages = new HashMap<String, String>();
         if (!unsyncedMessages.isEmpty()) {
 
             /*
@@ -1280,7 +1281,33 @@ public class MessagingController implements Runnable {
                 Log.d(K9.LOG_TAG, "SYNC: About to fetch " + unsyncedMessages.size() + " unsynced messages for folder " + folder);
 
 
-            fetchUnsyncedMessages(account, remoteFolder, localFolder, unsyncedMessages, smallMessages, largeMessages, progress, todo, fp);
+            fetchUnsyncedMessages(account, remoteFolder, localFolder, unsyncedMessages, smallMessages, largeMessages, spamMessages, progress, todo, fp);
+
+            if (spamMessages.size() > 0) {
+                if (K9.DEBUG) {
+                    Log.d(K9.LOG_TAG, "Moving " + spamMessages.size() +
+                            " messages to the Spam folder.");
+                }
+
+                queueMoveOrCopy(account, localFolder.getName(), account.getSpamFolderName(), false,
+                        spamMessages.keySet().toArray(EMPTY_STRING_ARRAY), spamMessages);
+                spamMessages.clear();
+
+                try {
+                    processPendingCommandsSynchronous(account);
+                } catch (Exception e) {
+                    addErrorMessage(account, null, e);
+                    Log.e(K9.LOG_TAG, "Failure processing command, but continuing message sync attempt", e);
+                }
+
+                // FIXME: This is bad!
+                // ImapStore is using a cache for ImapFolder instances which causes our remoteFolder
+                // object to be used and later closed by processPendingMoveOrCopy(). So we have to
+                // re-open it here.
+                if (!remoteFolder.isOpen()) {
+                    remoteFolder.open(OpenMode.READ_WRITE);
+                }
+            }
 
             // If a message didn't exist, messageFinished won't be called, but we shouldn't try again
             // If we got here, nothing failed
@@ -1433,6 +1460,7 @@ public class MessagingController implements Runnable {
                                        List<Message> unsyncedMessages,
                                        final ArrayList<Message> smallMessages,
                                        final ArrayList<Message> largeMessages,
+                                       final Map<String, String> spamMessages,
                                        final AtomicInteger progress,
                                        final int todo,
                                        FetchProfile fp) throws MessagingException {
@@ -1445,6 +1473,11 @@ public class MessagingController implements Runnable {
          */
         final List<Message> chunk = new ArrayList<Message>(UNSYNC_CHUNK_SIZE);
 
+        final String spamFolderName = account.getSpamFolderName();
+        final LocalFolder spamFolder = account.getLocalStore().getFolder(spamFolderName);
+        final boolean isSpamFilterEnabled = (account.isSpamAssassinFilterEnabled() &&
+                !spamFolder.equals(localFolder));
+
         remoteFolder.fetch(unsyncedMessages.toArray(EMPTY_MESSAGE_ARRAY), fp,
         new MessageRetrievalListener() {
             @Override
@@ -1472,6 +1505,15 @@ public class MessagingController implements Runnable {
                         return;
                     }
 
+                    if (isSpamFilterEnabled && isSpam(message)) {
+                        // Write message to the local Spam folder
+                        Map<String, String> uidMap = spamFolder.insertAsLocalMessages(
+                                new Message[] { message });
+
+                        spamMessages.putAll(uidMap);
+                        return;
+                    }
+
                     if (account.getMaximumAutoDownloadMessageSize() > 0 &&
                     message.getSize() > account.getMaximumAutoDownloadMessageSize()) {
                         largeMessages.add(message);
@@ -1518,6 +1560,11 @@ public class MessagingController implements Runnable {
         }
     }
 
+    private boolean isSpam(Message message) throws MessagingException {
+        String[] headers = message.getHeader(K9.SPAM_FLAG_HEADER);
+        return (headers != null && headers.length > 0 && headers[0].equalsIgnoreCase("YES"));
+    }
+
     /**
      * Actual storing of messages
      *

src/com/fsck/k9/mail/store/ImapStore.java

@@ -1492,7 +1492,8 @@ public class ImapStore extends Store {
                 fetchFields.add("INTERNALDATE");
                 fetchFields.add("RFC822.SIZE");
                 fetchFields.add("BODY.PEEK[HEADER.FIELDS (date subject from content-type to cc " +
-                        "reply-to message-id references in-reply-to " + K9.IDENTITY_HEADER + ")]");
+                        "reply-to message-id references in-reply-to " + K9.SPAM_FLAG_HEADER +
+                        " " + K9.IDENTITY_HEADER + ")]");
             }
             if (fp.contains(FetchProfile.Item.STRUCTURE)) {
                 fetchFields.add("BODYSTRUCTURE");

src/com/fsck/k9/mail/store/LocalStore.java

@@ -2130,7 +2130,7 @@ public class LocalStore extends Store implements Serializable {
             if (!(folder instanceof LocalFolder)) {
                 throw new MessagingException("copyMessages called with incorrect Folder");
             }
-            return ((LocalFolder) folder).appendMessages(msgs, true);
+            return ((LocalFolder) folder).appendMessages(msgs, true, false);
         }
 
         @Override
@@ -2299,7 +2299,7 @@ public class LocalStore extends Store implements Serializable {
          */
         @Override
         public Map<String, String> appendMessages(Message[] messages) throws MessagingException {
-            return appendMessages(messages, false);
+            return appendMessages(messages, false, false);
         }
 
         public void destroyMessages(final Message[] messages) {
@@ -2389,6 +2389,11 @@ public class LocalStore extends Store implements Serializable {
             return null;
         }
 
+        public Map<String, String> insertAsLocalMessages(Message[] messages)
+                throws MessagingException {
+            return appendMessages(messages, false, true);
+        }
+
         /**
          * The method differs slightly from the contract; If an incoming message already has a uid
          * assigned and it matches the uid of an existing message then this message will replace
@@ -2401,9 +2406,14 @@ public class LocalStore extends Store implements Serializable {
          * message, retrieve the appropriate local message instance first (if it already exists).
          * @param messages
          * @param copy
+         * @param createAsLocal
+         *         If {@code true} the message will get a local UID. The mapping is added to the map
+         *         that is returned by this method.
+         *
          * @return Map<String, String> uidMap of srcUids -> destUids
          */
-        private Map<String, String> appendMessages(final Message[] messages, final boolean copy) throws MessagingException {
+        private Map<String, String> appendMessages(final Message[] messages, final boolean copy,
+                final boolean createAsLocal) throws MessagingException {
             open(OpenMode.READ_WRITE);
             try {
                 final Map<String, String> uidMap = new HashMap<String, String>();
@@ -2418,14 +2428,14 @@ public class LocalStore extends Store implements Serializable {
 
                                 long oldMessageId = -1;
                                 String uid = message.getUid();
-                                if (uid == null || copy) {
+                                if (uid == null || copy || createAsLocal) {
                                     /*
                                      * Create a new message in the database
                                      */
                                     String randomLocalUid = K9.LOCAL_UID_PREFIX +
                                             UUID.randomUUID().toString();
 
-                                    if (copy) {
+                                    if (copy || createAsLocal) {
                                         // Save mapping: source UID -> target UID
                                         uidMap.put(uid, randomLocalUid);
                                     } else {