csync: Use an explicit instruction for should_update_metadata

The current way of tracking the need to update the metadata without
propagation using a separate flag makes it difficult to track
priorities between the local and remote tree. The logic is also
difficult to logically cover since the possibilities matrix isn't
100% covered, leaving the flag only used in a few situations
(mostly involving folders, but not only).

The reason we need to change this is to be able to track the sync
state of files for overlay icons. The instruction alone can't be
used since CSYNC_INSTRUCTION_SYNC is used for folders even though
they won't be propagated. Removing this logic is however not possible
without using something else than CSYNC_INSTRUCTION_NONE since too
many codepath interpret (rightfully) this as meaning "nothing to do".

This patch adds a new CSYNC_INSTRUCTION_UPDATE_METADATA instruction
to let the update and reconcile steps tell the SyncEngine to update
the metadata of a file without any propagation. Other flags are left
to be interpretted by the implementation as implicitly needing
metadata update or not, as this was already the case for most file
propagation jobs. For example, CSYNC_INSTRUCTION_NEW for directories
now also implicitly update the metadata.

Since it's not impossible for folders to emit CSYNC_INSTRUCTION_SYNC
or CSYNC_INSTRUCTION_CONFLICT, the corresponding code paths in the
sync engine have been removed.

Since the reconcile step can now know if the local tree needs metadata
update while the remote side might want propagation, the
localMetadataUpdate logic in SyncEngine::treewalkFile now simply use
a CSYNC_INSTRUCTION_UPDATE_METADATA for the local side, which is now
implemented as a different database query.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/gui/syncrunfilelog.cpp b/src/gui/syncrunfilelog.cpp
index bc312cc3d..04d1763ad 100644
--- a/src/gui/syncrunfilelog.cpp
+++ b/src/gui/syncrunfilelog.cpp
@@ -81,6 +81,9 @@ QString SyncRunFileLog::instructionToStr( csync_instructions_e inst )
     case CSYNC_INSTRUCTION_TYPE_CHANGE:
         re = "INST_TYPE_CHANGE";
         break;
+    case CSYNC_INSTRUCTION_UPDATE_METADATA:
+        re = "INST_METADATA";
+        break;
     }
 
     return re;