SF #2095433: regression in 0.8: one-way sync of virtual birthday calendar

"refresh-from-client" works again for the birthday calendar.

In contrast to previous releases SyncEvolution now does some sanity checks
that the sync mode is right. For all modes other than "refresh-from-server"
and "slow" the following error is reported:

22:39:34 [INFO] ical20: sync mode is 'refresh from server'
22:39:34 [ERROR] ical20: could not read revision identifier for item pas-id-43C0ED3900000001-anniversary-rid: only refresh-from-client synchronization is supported

"slow" syncs may or may not work, depending on whether the server sends
back updates. Better don't use it. If the server sends back items during a
slow sync, then the error message is a bit cryptic:

22:47:02 [INFO] ical20: eg2fVHx6bZ6VF2MR5TgdHQ==: add
22:47:02 [INFO] ical20: eg2fVHx6bZ6VF2MR5TgdHQ==: exists already, updating instead
22:47:02 [ERROR] ical20: updating item eg2fVHx6bZ6VF2MR5TgdHQ==: Unknown error


git-svn-id: https://zeitsenke.de/svn/SyncEvolution/trunk@752 15ad00c4-1369-45f4-8270-35d70d36bdcd

src/backends/evolution/EvolutionCalendarSource.cpp

@@ -726,8 +726,12 @@ string EvolutionCalendarSource::getItemModTime(ECalComponent *ecomp)
 {
     struct icaltimetype *modTime;
     e_cal_component_get_last_modified(ecomp, &modTime);
-    eptr<struct icaltimetype, struct icaltimetype, EvolutionUnrefFree<struct icaltimetype> > modTimePtr(modTime, "item without modification time");
-    return icalTime2Str(*modTimePtr);
+    eptr<struct icaltimetype, struct icaltimetype, EvolutionUnrefFree<struct icaltimetype> > modTimePtr(modTime);
+    if (!modTimePtr) {
+        return "";
+    } else {
+        return icalTime2Str(*modTimePtr);
+    }
 }
 
 string EvolutionCalendarSource::getItemModTime(const ItemID &id)
@@ -735,11 +739,11 @@ string EvolutionCalendarSource::getItemModTime(const ItemID &id)
     eptr<icalcomponent> icomp(retrieveItem(id));
     icalproperty *lastModified = icalcomponent_get_first_property(icomp, ICAL_LASTMODIFIED_PROPERTY);
     if (!lastModified) {
-        throwError("getItemModTime(): item without modification time");
+        return "";
+    } else {
+        struct icaltimetype modTime = icalproperty_get_lastmodified(lastModified);
+        return icalTime2Str(modTime);
     }
-    struct icaltimetype modTime = icalproperty_get_lastmodified(lastModified);
-    return icalTime2Str(modTime);
-
 }
 
 string EvolutionCalendarSource::icalTime2Str(const icaltimetype &tt)

src/backends/evolution/EvolutionCalendarSource.h

@@ -151,12 +151,14 @@ class EvolutionCalendarSource : public TrackingSyncSource
 
     /**
      * Extract modification string from calendar item.
+     * @return empty string if no time was available
      */
     string getItemModTime(ECalComponent *ecomp);
 
     /**
      * Extract modification string of an item stored in
      * the calendar.
+     * @return empty string if no time was available
      */
     string getItemModTime(const ItemID &id);
 

src/core/TrackingSyncSource.cpp

@@ -53,6 +53,18 @@ void TrackingSyncSource::beginSyncThrow(bool needAll,
         const string &uid = mapping.first;
         const string &revision = mapping.second;
 
+        // uid must always be non-empty whereas
+        // revision may be empty when doing refresh-from-client
+        // syncs; refresh-from-client cannot be distinguished
+        // from slow syncs, so allow slow syncs, too
+        if (uid.empty()) {
+            throwError("could not read UID for an item");
+        }
+        bool fromClient = needAll && !needPartial && !deleteLocal;
+        if (!fromClient && revision.empty()) {
+            throwError(string("could not read revision identifier for item ") + uid + ": only refresh-from-client synchronization is supported");
+        }
+
         if (deleteLocal) {
             deleteItem(uid);
         } else {
@@ -132,6 +144,9 @@ int TrackingSyncSource::addItemThrow(SyncItem& item)
 {
     InsertItemResult res = insertItem("", item);
     item.setKey(res.m_uid.c_str());
+    if (res.m_uid.empty() || res.m_revision.empty()) {
+        throwError("could not add item");
+    }
     m_trackingNode->setProperty(res.m_uid, res.m_revision);
     return res.m_merged ? STC_CONFLICT_RESOLVED_WITH_MERGE : STC_OK;
 }
@@ -144,6 +159,9 @@ int TrackingSyncSource::updateItemThrow(SyncItem& item)
         m_trackingNode->removeProperty(uid);
     }
     item.setKey(res.m_uid.c_str());
+    if (res.m_uid.empty() || res.m_revision.empty()) {
+        throwError("could not update item");
+    }
     m_trackingNode->setProperty(res.m_uid, res.m_revision);
     return res.m_merged ? STC_CONFLICT_RESOLVED_WITH_MERGE : STC_OK;
 }

src/core/TrackingSyncSource.h

@@ -92,6 +92,14 @@ class TrackingSyncSource : public EvolutionSyncSource
     /**
      * fills the complete mapping from UID to revision string of all
      * currently existing items
+     *
+     * Usually both UID and revision string must be non-empty. The
+     * only exception is a refresh-from-client: in that case the
+     * revision string may be empty. The implementor of this call
+     * cannot know whether empty strings are allowed, therefore it
+     * should not throw errors when it cannot create a non-empty
+     * string. The caller of this method will detect situations where
+     * a non-empty string is necessary and none was provided.
      */
     virtual void listAllItems(RevisionMap_t &revisions) = 0;
 
@@ -130,7 +138,9 @@ class TrackingSyncSource : public EvolutionSyncSource
      * This error should be reported instead of covering it up by
      * (re)creating the item.
      *
-     * Errors are signalled by throwing an exception. 
+     * Errors are signalled by throwing an exception. Returning empty
+     * strings in the result is an error which triggers an "item could
+     * not be stored" error.
      *
      * @param uid      identifies the item to be modified, empty for creating
      * @param item     contains the new content of the item and its MIME type