TestingSyncSource+CalDAV: added "delete all" API call

During testing, removing all items is done via a special call in
TestingSyncSource. It used to be an utility method which fell back to
the normal SyncSource API.

This patch changes several things
- Reversed order in which items are deleted in that utility method,
  because removing children (= longer IDs) first tends to be supported
  better by servers (bug in CalDAV server, but still...).
- Allow backends to implement their own removeAllItems().
- Implement that in CalDAV + MapSyncSource as removing the merged
  items directly, instead of using a sequence of PUT+final DELETE.

Found while testing with Bedework CalDAV server. Makes testing more
robust and efficient.

src/backends/webdav/CalDAVSource.cpp

@@ -858,6 +858,48 @@ std::string CalDAVSource::removeSubItem(const string &davLUID, const std::string
     }
 }
 
+void CalDAVSource::removeMergedItem(const std::string &davLUID)
+{
+    EventCache::iterator it = m_cache.find(davLUID);
+    if (it == m_cache.end()) {
+        // gone already, no need to do anything
+        SE_LOG_DEBUG(this, NULL, "%s: ignoring request to delete non-existent item",
+                     davLUID.c_str());
+        return;
+    }
+    // use item as it is, load only if it is not going to be removed entirely
+    Event &event = *it->second;
+
+    // remove entire merged item, nothing will be left after removal
+    try {
+        removeItem(event.m_DAVluid);
+    } catch (const TransportStatusException &ex) {
+        if (ex.syncMLStatus() == 404) {
+            // Someone must have created a detached recurrence on
+            // the server without the master event - or the 
+            // item was already removed while the sync ran.
+            // Let's log the problem and ignore it.
+            Exception::log();
+        } else if (ex.syncMLStatus() == 409 &&
+                   strstr(ex.what(), "Can't delete a recurring event")) {
+            // Google CalDAV:
+            // HTTP/1.1 409 Can't delete a recurring event except on its organizer's calendar
+            //
+            // Workaround: use the workarounds from removeSubItem()
+            std::set<std::string> subids = event.m_subids;
+            for (std::set<std::string>::reverse_iterator it = subids.rbegin();
+                 it != subids.rend();
+                 ++it) {
+                removeSubItem(davLUID, *it);
+            }
+        } else {
+            throw;
+        }
+    }
+
+    m_cache.erase(davLUID);
+}
+
 void CalDAVSource::flushItem(const string &davLUID)
 {
     // TODO: currently we always flush immediately, so no need to send data here

src/backends/webdav/CalDAVSource.h

@@ -42,6 +42,7 @@ class CalDAVSource : public WebDAVSource,
                                         const std::string &item);
     virtual void readSubItem(const std::string &uid, const std::string &subid, std::string &item);
     virtual std::string removeSubItem(const string &uid, const std::string &subid);
+    virtual void removeMergedItem(const std::string &luid);
     virtual void flushItem(const string &uid);
     virtual std::string getSubDescription(const string &uid, const string &subid);
 

src/syncevo/MapSyncSource.cpp

@@ -351,4 +351,13 @@ std::pair<std::string, std::string> MapSyncSource::splitLUID(const std::string &
 
 StringEscape MapSyncSource::m_escape('%', "/");
 
+void MapSyncSource::removeAllItems()
+{
+    BOOST_FOREACH(const SubRevisionMap_t::value_type &entry,
+                  m_revisions) {
+        m_sub->removeMergedItem(entry.first);
+    }
+    m_revisions.clear();
+}
+
 SE_END_CXX

src/syncevo/MapSyncSource.h

@@ -166,6 +166,11 @@ class SubSyncSource : virtual public SyncSourceBase
      */
     virtual std::string removeSubItem(const string &mainid, const std::string &subid) = 0;
 
+    /**
+     * Remove all sub-items belonging to mainid.
+     */
+    virtual void removeMergedItem(const std::string &mainid) = 0;
+
     /**
      * Called whenever this class thinks that the item may no longer be
      * needed. Might be wrong...
@@ -265,6 +270,9 @@ class MapSyncSource :
     virtual std::string getDescription(sysync::KeyH aItemKey) { return dynamic_cast<SyncSourceLogging &>(*m_sub).getDescription(aItemKey); }
     virtual std::string getDescription(const string &luid);
 
+    /* TestingSyncSource */
+    virtual void removeAllItems();
+
  private:
     boost::shared_ptr<SubSyncSource> m_sub;
     /** escape / in uid with %2F, so that splitMainIDValue() and splitLUID() can use / as separator */

src/syncevo/SyncSource.cpp

@@ -1388,5 +1388,20 @@ void SyncSourceBlob::init(SyncSource::Operations &ops,
                                    _1, _2);
 }
 
+void TestingSyncSource::removeAllItems()
+{
+    // remove longest luids first:
+    // for luid=UID[+RECURRENCE-ID] that will
+    // remove children from a merged event first,
+    // which is better supported by certain servers
+    Items_t items = getAllItems();
+    for (Items_t::reverse_iterator it = items.rbegin();
+         it != items.rend();
+         ++it) {
+        deleteItem(*it);
+    }
+}
+
+
 SE_END_CXX
 

src/syncevo/SyncSource.h

@@ -2081,11 +2081,7 @@ class TestingSyncSource : public SyncSource,
 
     virtual SourceType getSourceType() const { return SyncSourceConfig::getSourceType(); }
 
-    void removeAllItems() {
-        BOOST_FOREACH(const string &luid, getAllItems()) {
-            deleteItem(luid);
-        }
-    }
+    virtual void removeAllItems();
 };