Prepare custom IMAP folder/message implementation

app/src/main/java/eu/faircode/email/EmailService.java

@@ -279,6 +279,9 @@ public class EmailService implements AutoCloseable {
             properties.put("mail." + protocol + ".peek", "true");
             properties.put("mail." + protocol + ".appendbuffersize", Integer.toString(APPEND_BUFFER_SIZE));
 
+            if (!"gimaps".equals(protocol) && BuildConfig.DEBUG)
+                properties.put("mail." + protocol + ".folder.class", IMAPFolderEX.class.getName());
+
         } else if ("smtp".equals(protocol) || "smtps".equals(protocol)) {
             // https://javaee.github.io/javamail/docs/api/com/sun/mail/smtp/package-summary.html#properties
             properties.put("mail.smtps.starttls.enable", "false");

app/src/main/java/eu/faircode/email/IMAPFolderEX.java

@@ -0,0 +1,167 @@
+package eu.faircode.email;
+
+/*
+    This file is part of FairEmail.
+
+    FairEmail is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    FairEmail is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with FairEmail.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2018-2022 by Marcel Bokhorst (M66B)
+*/
+
+import com.sun.mail.iap.Argument;
+import com.sun.mail.iap.CommandFailedException;
+import com.sun.mail.iap.ConnectionException;
+import com.sun.mail.iap.ProtocolException;
+import com.sun.mail.iap.Response;
+import com.sun.mail.imap.IMAPFolder;
+import com.sun.mail.imap.IMAPMessage;
+import com.sun.mail.imap.IMAPStore;
+import com.sun.mail.imap.Utility;
+import com.sun.mail.imap.protocol.IMAPProtocol;
+import com.sun.mail.imap.protocol.ListInfo;
+import com.sun.mail.imap.protocol.MessageSet;
+import com.sun.mail.imap.protocol.UIDSet;
+
+import javax.mail.FetchProfile;
+import javax.mail.Flags;
+import javax.mail.Folder;
+import javax.mail.FolderClosedException;
+import javax.mail.FolderNotFoundException;
+import javax.mail.Message;
+import javax.mail.MessageRemovedException;
+import javax.mail.MessagingException;
+import javax.mail.UIDFolder;
+
+public class IMAPFolderEX extends IMAPFolder {
+    public IMAPFolderEX(String fullName, char separator, IMAPStore store, Boolean isNamespace) {
+        super(fullName, separator, store, isNamespace);
+    }
+
+    public IMAPFolderEX(ListInfo li, IMAPStore store) {
+        super(li, store);
+    }
+
+    @Override
+    public synchronized void setFlags(Message[] msgs, Flags flag, boolean value) throws MessagingException {
+        checkOpened();
+        // checkFlags(flag);
+
+        if (msgs.length == 0)
+            return;
+
+        synchronized (messageCacheLock) {
+            try {
+                IMAPProtocol p = getProtocol();
+                if (p.hasCapability("X-UIDONLY") ||
+                        (p.hasCapability("UIDPLUS") &&
+                                Boolean.parseBoolean(System.getProperty("fairemail.uid_command")))) {
+                    // Verizon
+                    FetchProfile fp = new FetchProfile();
+                    fp.add(UIDFolder.FetchProfileItem.UID);
+                    fetch(msgs, fp);
+
+                    UIDSet[] uids = Utility.toUIDSet(msgs);
+                    if (uids == null)
+                        return;
+
+                    Response[] r = p.command("UID STORE " + UIDSet.toString(uids) +
+                            " " + (value ? '+' : '-') + "FLAGS " + p.createFlagList(new Flags(flag)), null);
+                    p.notifyResponseHandlers(r);
+                    p.handleResult(r[r.length - 1]);
+                    return;
+                }
+                MessageSet[] ms = Utility.toMessageSetSorted(msgs, null);
+                if (ms == null)
+                    throw new MessageRemovedException("Messages have been removed");
+                p.storeFlags(ms, flag, value);
+            } catch (ConnectionException cex) {
+                throw new FolderClosedException(this, cex.getMessage());
+            } catch (ProtocolException pex) {
+                throw new MessagingException(pex.getMessage(), pex);
+            }
+        }
+    }
+
+    @Override
+    public synchronized void copyMessages(Message[] msgs, Folder folder) throws MessagingException {
+        copyMessages(msgs, folder, false);
+    }
+
+    public synchronized void moveMessages(Message[] msgs, Folder folder) throws MessagingException {
+        copyMessages(msgs, folder, true);
+    }
+
+    private synchronized void copyMessages(Message[] msgs, Folder folder, boolean move) throws MessagingException {
+        checkOpened();
+
+        if (msgs.length == 0)
+            return;
+
+        if (folder.getStore() == store) {
+            synchronized (messageCacheLock) {
+                try {
+                    IMAPProtocol p = getProtocol();
+                    if (p.hasCapability("X-UIDONLY") ||
+                            (p.hasCapability("UIDPLUS") &&
+                                    Boolean.parseBoolean(System.getProperty("fairemail.uid_command")))) {
+                        // Verizon
+                        FetchProfile fp = new FetchProfile();
+                        fp.add(UIDFolder.FetchProfileItem.UID);
+                        fetch(msgs, fp);
+
+                        UIDSet[] uids = Utility.toUIDSet(msgs);
+                        if (uids == null)
+                            return;
+
+                        Argument args = new Argument();
+                        args.writeAtom(UIDSet.toString(uids));
+                        p.writeMailboxName(args, folder.getFullName());
+                        Response[] r = p.command(move ? "UID MOVE" : "UID COPY", args);
+                        p.notifyResponseHandlers(r);
+                        p.handleResult(r[r.length - 1]);
+                        return;
+                    }
+                    MessageSet[] ms = Utility.toMessageSet(msgs, null);
+                    if (ms == null)
+                        throw new MessageRemovedException("Messages have been removed");
+                    if (move)
+                        p.move(ms, folder.getFullName());
+                    else
+                        p.copy(ms, folder.getFullName());
+                } catch (CommandFailedException cfx) {
+                    if (cfx.getMessage() != null &&
+                            cfx.getMessage().contains("TRYCREATE"))
+                        throw new FolderNotFoundException(folder,
+                                folder.getFullName() + " does not exist");
+                    else
+                        throw new MessagingException(cfx.getMessage(), cfx);
+                } catch (ConnectionException cex) {
+                    throw new FolderClosedException(this, cex.getMessage());
+                } catch (ProtocolException pex) {
+                    throw new MessagingException(pex.getMessage(), pex);
+                }
+            }
+        } else {
+            if (move)
+                throw new MessagingException("Move between stores not supported");
+            else
+                super.copyMessages(msgs, folder);
+        }
+    }
+
+    @Override
+    public IMAPMessage newIMAPMessage(int msgnum) {
+        return new IMAPMessageEx(this, msgnum);
+    }
+}

app/src/main/java/eu/faircode/email/IMAPMessageEx.java

@@ -0,0 +1,76 @@
+package eu.faircode.email;
+
+/*
+    This file is part of FairEmail.
+
+    FairEmail is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    FairEmail is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with FairEmail.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2018-2022 by Marcel Bokhorst (M66B)
+*/
+
+import com.sun.mail.iap.ConnectionException;
+import com.sun.mail.iap.ProtocolException;
+import com.sun.mail.iap.Response;
+import com.sun.mail.imap.IMAPFolder;
+import com.sun.mail.imap.IMAPMessage;
+import com.sun.mail.imap.protocol.IMAPProtocol;
+import com.sun.mail.imap.protocol.UID;
+
+import javax.mail.Flags;
+import javax.mail.FolderClosedException;
+import javax.mail.MessagingException;
+import javax.mail.Session;
+
+public class IMAPMessageEx extends IMAPMessage {
+    protected IMAPMessageEx(IMAPFolder folder, int msgnum) {
+        super(folder, msgnum);
+    }
+
+    protected IMAPMessageEx(Session session) {
+        super(session);
+    }
+
+    @Override
+    public synchronized void setFlags(Flags flag, boolean set) throws MessagingException {
+        synchronized (getMessageCacheLock()) {
+            try {
+                IMAPProtocol p = getProtocol();
+                checkExpunged(); // Insure that this message is not expunged
+                if (p.hasCapability("X-UIDONLY") ||
+                        "imap.mail.yahoo.co.jp".equals(p.getInetAddress().getHostName()) ||
+                        (p.hasCapability("UIDPLUS") &&
+                                Boolean.parseBoolean(System.getProperty("fairemail.uid_command")))) {
+                    // Verizon
+                    // Yahoo: NO [CANNOT] STORE It's not possible to perform specified operation
+                    long uid = getUID();
+                    if (uid < 0) {
+                        UID u = p.fetchUID(getSequenceNumber());
+                        if (u != null)
+                            uid = u.uid;
+                    }
+                    Response[] r = p.command("UID STORE " + uid +
+                            " " + (set ? '+' : '-') + "FLAGS " + p.createFlagList(new Flags(flag)), null);
+                    p.notifyResponseHandlers(r);
+                    p.handleResult(r[r.length - 1]);
+                    return;
+                }
+                p.storeFlags(getSequenceNumber(), flag, set);
+            } catch (ConnectionException cex) {
+                throw new FolderClosedException(folder, cex.getMessage());
+            } catch (ProtocolException pex) {
+                throw new MessagingException(pex.getMessage(), pex);
+            }
+        }
+    }
+}