private Document ResolveFunc(Conflict conflict)
{
if (conflict.RemoteDocument == null || conflict.LocalDocument == null)
{
return(null);
}
else if (conflict.LocalDocument.Generation > conflict.RemoteDocument.Generation)
{
return(conflict.LocalDocument);
}
else if (conflict.LocalDocument.Generation < conflict.RemoteDocument.Generation)
{
return(conflict.RemoteDocument);
}
else
{
return(String.CompareOrdinal(conflict.LocalDocument.RevID, conflict.RemoteDocument.RevID) > 0
? conflict.LocalDocument : conflict.RemoteDocument);
}
}
internal void ResolveConflict([NotNull] string docID, [NotNull] IConflictResolver resolver)
{
Debug.Assert(docID != null);
Document doc = null, otherDoc = null, baseDoc = null;
var inConflict = true;
while (inConflict)
{
ThreadSafety.DoLocked(() =>
{
LiteCoreBridge.Check(err => Native.c4db_beginTransaction(_c4db, err));
try {
doc = new Document(this, docID);
if (!doc.Exists)
{
doc.Dispose();
return;
}
otherDoc = new Document(this, docID);
if (!otherDoc.Exists)
{
doc.Dispose();
otherDoc.Dispose();
return;
}
otherDoc.SelectConflictingRevision();
baseDoc = new Document(this, docID);
if (!baseDoc.SelectCommonAncestor(doc, otherDoc) || baseDoc.ToDictionary() == null)
{
baseDoc.Dispose();
baseDoc = null;
}
LiteCoreBridge.Check(err => Native.c4db_endTransaction(_c4db, true, err));
} catch (Exception) {
doc?.Dispose();
otherDoc?.Dispose();
baseDoc?.Dispose();
LiteCoreBridge.Check(err => Native.c4db_endTransaction(_c4db, false, err));
}
});
var conflict = new Conflict(doc, otherDoc, baseDoc);
var logID = new SecureLogString(doc.Id, LogMessageSensitivity.PotentiallyInsecure);
Log.To.Database.I(Tag, $"Resolving doc '{logID}' with {resolver.GetType().Name} (mine={doc.RevID}, theirs={otherDoc.RevID}, base={baseDoc?.RevID})");
Document resolved = null;
try {
resolved = resolver.Resolve(conflict);
if (resolved == null)
{
throw new LiteCoreException(new C4Error(C4ErrorCode.Conflict));
}
SaveResolvedDocument(resolved, conflict);
inConflict = false;
} catch (LiteCoreException e) {
if (e.Error.domain == C4ErrorDomain.LiteCoreDomain && e.Error.code == (int)C4ErrorCode.Conflict)
{
continue;
}
throw;
} finally {
resolved?.Dispose();
if (resolved != doc)
{
doc?.Dispose();
}
if (resolved != otherDoc)
{
otherDoc?.Dispose();
}
if (resolved != baseDoc)
{
baseDoc?.Dispose();
}
}
}
}
/// <summary>
/// The callback default conflict resolve method, if conflict occurs.
/// </summary>
public Document Resolve(Conflict conflict)
{
return(ResolveFunc(conflict));
}
private Document Save([NotNull] Document document, bool deletion)
{
if (document.IsInvalidated)
{
throw new CouchbaseLiteException(StatusCode.NotAllowed, "Cannot save or delete a MutableDocument that has already been used to save or delete");
}
if (deletion && document.RevID == null)
{
throw new CouchbaseLiteException(StatusCode.NotAllowed, "Cannot delete a document that has not yet been saved");
}
var docID = document.Id;
var doc = document;
Document baseDoc = null, otherDoc = null;
C4Document *newDoc = null;
Document retVal = null;
while (true)
{
var resolve = false;
retVal = ThreadSafety.DoLocked(() =>
{
VerifyDB(doc);
LiteCoreBridge.Check(err => Native.c4db_beginTransaction(_c4db, err));
try {
if (deletion)
{
// Check for no-op case if the document does not exist
var curDoc = (C4Document *)NativeHandler.Create().AllowError(new C4Error(C4ErrorCode.NotFound))
.Execute(err => Native.c4doc_get(_c4db, docID, true, err));
if (curDoc == null)
{
(document as MutableDocument)?.MarkAsInvalidated();
return(null);
}
Native.c4doc_free(curDoc);
}
var newDocOther = newDoc;
Save(doc, &newDocOther, baseDoc?.c4Doc?.HasValue == true ? baseDoc.c4Doc.RawDoc : null, deletion);
if (newDocOther != null)
{
// Save succeeded, so commit
newDoc = newDocOther;
LiteCoreBridge.Check(err =>
{
var success = Native.c4db_endTransaction(_c4db, true, err);
if (!success)
{
Native.c4doc_free(newDoc);
}
return(success);
});
(document as MutableDocument)?.MarkAsInvalidated();
baseDoc?.Dispose();
return(new Document(this, docID, new C4DocumentWrapper(newDoc)));
}
// There was a conflict
if (deletion && !doc.IsDeleted)
{
var deletedDoc = doc.ToMutable();
deletedDoc.MarkAsDeleted();
doc = deletedDoc;
}
if (doc.c4Doc != null)
{
baseDoc = new Document(this, docID, doc.c4Doc.Retain <C4DocumentWrapper>());
}
otherDoc = new Document(this, docID);
if (!otherDoc.Exists)
{
LiteCoreBridge.Check(err => Native.c4db_endTransaction(_c4db, false, err));
return(null);
}
} catch (Exception) {
baseDoc?.Dispose();
otherDoc?.Dispose();
LiteCoreBridge.Check(err => Native.c4db_endTransaction(_c4db, false, err));
throw;
}
resolve = true;
LiteCoreBridge.Check(err => Native.c4db_endTransaction(_c4db, false, err));
return(null);
});
if (!resolve)
{
return(retVal);
}
// Resolve Conflict
Document resolved = null;
try {
var resolver = Config.ConflictResolver;
var conflict = new Conflict(doc, otherDoc, baseDoc);
resolved = resolver.Resolve(conflict);
if (resolved == null)
{
throw new LiteCoreException(new C4Error(C4ErrorCode.Conflict));
}
} finally {
baseDoc?.Dispose();
if (!ReferenceEquals(resolved, otherDoc))
{
otherDoc?.Dispose();
}
}
retVal = ThreadSafety.DoLocked(() =>
{
var current = new Document(this, docID);
if (resolved.RevID == current.RevID)
{
(document as MutableDocument)?.MarkAsInvalidated();
current.Dispose();
return(resolved); // Same as current
}
// For saving
doc = resolved;
baseDoc = current;
deletion = resolved.IsDeleted;
return(null);
});
if (retVal != null)
{
return(retVal);
}
}
}
