Feature/rfc 6578

cosmo-api/src/main/java/org/unitedinternet/cosmo/dao/ModificationDao.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2026 United Internet
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.unitedinternet.cosmo.dao;
+
+import java.util.List;
+
+import org.unitedinternet.cosmo.model.CollectionModification;
+
+/**
+ * <p>
+ * Persistent per-collection change log backing RFC 6578
+ * <code>DAV:sync-collection</code> incremental synchronization. Every
+ * membership change of a collection appends exactly one
+ * {@link CollectionModification} row whose server-assigned id is globally
+ * monotonic.
+ * </p>
+ */
+public interface ModificationDao {
+
+    /**
+     * Appends one change record to a collection's log.
+     *
+     * @param collectionUid uid of the collection whose membership changed
+     * @param memberUid uid of the affected member item
+     * @param memberName name of the affected member item at the time of the
+     *        change (needed to report tombstones for deletions)
+     * @param modType one of {@link CollectionModification#MOD_TYPE_CREATED},
+     *        {@link CollectionModification#MOD_TYPE_MODIFIED} or
+     *        {@link CollectionModification#MOD_TYPE_DELETED}
+     */
+    void log(String collectionUid, String memberUid, String memberName,
+             char modType);
+
+    /**
+     * Returns the change records of a collection that were appended
+     * <em>after</em> the given revision, ordered by ascending revision.
+     *
+     * @param collectionUid uid of the collection to query
+     * @param sinceRevision exclusive lower bound (a client's previously seen
+     *        token value)
+     * @param limit maximum number of records to return; a negative value
+     *        means no limit
+     */
+    List<CollectionModification> findSince(String collectionUid,
+                                           long sinceRevision,
+                                           int limit);
+
+    /**
+     * The highest revision ever assigned (0 when the log is empty). This is
+     * the numeric part of the freshest sync token the server can issue.
+     */
+    long currentRevision();
+}

cosmo-api/src/main/java/org/unitedinternet/cosmo/model/CollectionModification.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2026 United Internet
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.unitedinternet.cosmo.model;
+
+/**
+ * <p>
+ * A single entry in a collection's persistent change log. Each record captures
+ * one membership-affecting change ({@link #MOD_TYPE_CREATED creation},
+ * {@link #MOD_TYPE_MODIFIED modification} or {@link #MOD_TYPE_DELETED deletion}
+ * of a member) together with enough information to reconstruct the member's
+ * DAV:href even after deletion.
+ * </p>
+ *
+ * <p>
+ * The {@link #getId() id} is a globally monotonic server-assigned revision.
+ * It is the value encoded in RFC 6578 <code>DAV:sync-token</code>s issued by
+ * Cosmo ("urn:cosmo:sync-token:&lt;id&gt;") and orders all changes made to a
+ * collection.
+ * </p>
+ */
+public interface CollectionModification {
+
+    /** Change type: the member was created in the collection. */
+    char MOD_TYPE_CREATED = 'C';
+
+    /** Change type: an existing member of the collection changed. */
+    char MOD_TYPE_MODIFIED = 'M';
+
+    /** Change type (tombstone): the member was removed from the collection. */
+    char MOD_TYPE_DELETED = 'D';
+
+    /**
+     * Globally monotonic revision assigned by the server. Doubles as the
+     * numeric part of sync tokens and as the ordering key of the log.
+     */
+    Long getId();
+
+    /** Uid of the collection whose membership changed. */
+    String getCollectionUid();
+
+    /** Uid of the affected member item. */
+    String getMemberUid();
+
+    /**
+     * Name of the affected member item at the time of the change. Kept for
+     * deleted members so their old DAV:href can still be reported as a
+     * tombstone.
+     */
+    String getMemberName();
+
+    /** One of {@link #MOD_TYPE_CREATED}, {@link #MOD_TYPE_MODIFIED}, {@link #MOD_TYPE_DELETED}. */
+    char getModType();
+
+    /** Wall-clock timestamp of the change (informational; ordering uses the id). */
+    Long getTimestamp();
+}

cosmo-api/src/main/java/org/unitedinternet/cosmo/service/ContentService.java

@@ -15,9 +15,12 @@
  */
 package org.unitedinternet.cosmo.service;
 
+import java.util.List;
 import java.util.Set;
 import java.util.SortedSet;
 
+import org.unitedinternet.cosmo.model.CollectionModification;
+
 import org.unitedinternet.cosmo.model.CollectionItem;
 import org.unitedinternet.cosmo.model.ContentItem;
 import org.unitedinternet.cosmo.model.HomeCollectionItem;
@@ -427,4 +430,24 @@ public void removeTicket(Item item,
      */
     public void removeItemsFromCollection(CollectionItem collection);
 
+    /**
+     * Returns the change records of a collection's persistent change log that
+     * were appended after the given revision, ordered by ascending revision.
+     * Backs incremental DAV:sync-collection REPORT rounds (RFC 6578).
+     *
+     * @param collectionUid uid of the collection to query
+     * @param sinceRevision exclusive lower bound (client-held token value)
+     * @param limit maximum number of records; negative means no limit
+     * @return the matching {@link CollectionModification} records
+     */
+    List<CollectionModification> findModificationsSince(String collectionUid,
+                                                        long sinceRevision,
+                                                        int limit);
+
+    /**
+     * The highest revision currently assigned in the change log. This is the
+     * numeric part of the freshest sync token the server can issue.
+     */
+    long getModificationRevision();
+
 }

cosmo-core/src/main/java/org/unitedinternet/cosmo/dao/hibernate/ModificationDaoImpl.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2026 United Internet
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.unitedinternet.cosmo.dao.hibernate;
+
+import java.util.List;
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.PersistenceContext;
+import jakarta.persistence.TypedQuery;
+
+import org.springframework.stereotype.Repository;
+import org.unitedinternet.cosmo.dao.ModificationDao;
+import org.unitedinternet.cosmo.model.CollectionModification;
+import org.unitedinternet.cosmo.model.hibernate.HibCollectionModification;
+
+/**
+ * <p>
+ * Hibernate implementation of the persistent collection change log. Rows are
+ * never mutated after insertion; the AUTO_INCREMENT primary key provides the
+ * global monotonic revision used by sync tokens.
+ * </p>
+ */
+@Repository
+public class ModificationDaoImpl implements ModificationDao {
+
+    @PersistenceContext
+    protected EntityManager em;
+
+    public void log(String collectionUid, String memberUid,
+                    String memberName, char modType) {
+        em.persist(new HibCollectionModification(collectionUid, memberUid,
+                memberName, modType));
+        em.flush();
+    }
+
+    public List<CollectionModification> findSince(String collectionUid,
+                                                  long sinceRevision,
+                                                  int limit) {
+        TypedQuery<HibCollectionModification> query = em.createQuery(
+                "select m from HibCollectionModification m "
+                + "where m.collectionUid = :collectionUid and m.id > :since "
+                + "order by m.id asc",
+                HibCollectionModification.class);
+        query.setParameter("collectionUid", collectionUid);
+        query.setParameter("since", Long.valueOf(sinceRevision));
+        if (limit >= 0) {
+            query.setMaxResults(limit);
+        }
+        List<HibCollectionModification> result = query.getResultList();
+        return List.copyOf(result);
+    }
+
+    public long currentRevision() {
+        List<Long> revisions = em.createQuery(
+                "select max(m.id) from HibCollectionModification m",
+                Long.class).getResultList();
+        if (revisions.isEmpty() || revisions.get(0) == null) {
+            return 0L;
+        }
+        return revisions.get(0).longValue();
+    }
+}

cosmo-core/src/main/java/org/unitedinternet/cosmo/dav/impl/DavCollectionBase.java

@@ -54,6 +54,8 @@
 import org.unitedinternet.cosmo.dav.caldav.report.FreeBusyReport;
 import org.unitedinternet.cosmo.dav.caldav.report.MultigetReport;
 import org.unitedinternet.cosmo.dav.caldav.report.QueryReport;
+import org.unitedinternet.cosmo.dav.report.SyncCollectionReport;
+
 import org.unitedinternet.cosmo.dav.property.ExcludeFreeBusyRollup;
 import org.unitedinternet.cosmo.dav.property.WebDavProperty;
 import org.unitedinternet.cosmo.model.CollectionItem;
@@ -98,6 +100,8 @@ public class DavCollectionBase extends DavItemResourceBase implements DavItemCol
         REPORT_TYPES.add(PrincipalMatchReport.REPORT_TYPE_PRINCIPAL_MATCH);
         REPORT_TYPES
                 .add(PrincipalPropertySearchReport.REPORT_TYPE_PRINCIPAL_PROPERTY_SEARCH);
+        REPORT_TYPES.add(SyncCollectionReport.REPORT_TYPE_DAV_SYNC_COLLECTION);
+
 
         DEAD_PROPERTY_FILTER.add(CollectionItem.class.getName());
     }

cosmo-core/src/main/java/org/unitedinternet/cosmo/dav/provider/BaseProvider.java

@@ -276,11 +276,9 @@ public void report(DavRequest request, DavResponse response, WebDavResource reso
         try {
             ReportInfo info = request.getReportInfo();
             if (info == null) {
-                if (resource.isCollection()) {
-                    return;
-                } else {
-                    throw new BadRequestException("REPORT requires entity body");
-                }
+                // RFC 3253/6578: a REPORT without an entity body is invalid;
+                // silently ignoring it would leave the response unanswered.
+                throw new BadRequestException("REPORT requires entity body");
             }
             /*
              * Since the report type could not be determined in the security filter in order to check ticket permissions