/// <summary>
/// Get the correct Select changes command
/// Can be either
/// - SelectInitializedChanges : All changes for first sync
/// - SelectChanges : All changes filtered by timestamp
/// - SelectInitializedChangesWithFilters : All changes for first sync with filters
/// - SelectChangesWithFilters : All changes filtered by timestamp with filters
/// </summary>
private async Task <DbCommand> GetSelectChangesCommandAsync(SyncContext context, DbSyncAdapter syncAdapter, SyncTable syncTable, bool isNew)
{
DbCommand selectIncrementalChangesCommand;
DbCommandType dbCommandType;
SyncFilter tableFilter = null;
// Check if we have parameters specified
// Sqlite does not have any filter, since he can't be server side
if (this.CanBeServerProvider)
{
tableFilter = syncTable.GetFilter();
}
var hasFilters = tableFilter != null;
// Determing the correct DbCommandType
if (isNew && hasFilters)
{
dbCommandType = DbCommandType.SelectInitializedChangesWithFilters;
}
else if (isNew && !hasFilters)
{
dbCommandType = DbCommandType.SelectInitializedChanges;
}
else if (!isNew && hasFilters)
{
dbCommandType = DbCommandType.SelectChangesWithFilters;
}
else
{
dbCommandType = DbCommandType.SelectChanges;
}
// Get correct Select incremental changes command
selectIncrementalChangesCommand = syncAdapter.GetCommand(dbCommandType, tableFilter);
if (selectIncrementalChangesCommand == null)
{
throw new MissingCommandException(dbCommandType.ToString());
}
// Add common parameters
await syncAdapter.SetCommandParametersAsync(dbCommandType, selectIncrementalChangesCommand, tableFilter);
return(selectIncrementalChangesCommand);
}
/// <summary>
/// Handle a conflict
/// The int returned is the conflict count I need
/// </summary>
internal async Task <(ChangeApplicationAction, int, DmRow)> HandleConflictAsync(DbSyncAdapter syncAdapter, SyncContext context, SyncConflict conflict, ConflictResolutionPolicy policy, ScopeInfo scope, long fromScopeLocalTimeStamp, DbConnection connection, DbTransaction transaction)
{
DmRow finalRow = null;
var conflictApplyAction = ApplyAction.Continue;
(conflictApplyAction, finalRow) = await this.GetConflictActionAsync(context, conflict, policy, connection, transaction);
// Default behavior and an error occured
if (conflictApplyAction == ApplyAction.Rollback)
{
conflict.ErrorMessage = "Rollback action taken on conflict";
conflict.Type = ConflictType.ErrorsOccurred;
return(ChangeApplicationAction.Rollback, 0, null);
}
// Local provider wins, update metadata
if (conflictApplyAction == ApplyAction.Continue)
{
var isMergeAction = finalRow != null;
var row = isMergeAction ? finalRow : conflict.LocalRow;
// Conflict on a line that is not present on the datasource
if (row == null)
{
return(ChangeApplicationAction.Continue, 0, finalRow);
}
if (row != null)
{
// if we have a merge action, we apply the row on the server
if (isMergeAction)
{
bool isUpdated = false;
bool isInserted = false;
// Insert metadata is a merge, actually
var commandType = DbCommandType.UpdateMetadata;
isUpdated = syncAdapter.ApplyUpdate(row, scope, true);
if (!isUpdated)
{
// Insert the row
isInserted = syncAdapter.ApplyInsert(row, scope, true);
// Then update the row to mark this row as updated from server
// and get it back to client
isUpdated = syncAdapter.ApplyUpdate(row, scope, true);
commandType = DbCommandType.InsertMetadata;
}
if (!isUpdated && !isInserted)
{
throw new Exception("Can't update the merge row.");
}
// IF we have insert the row in the server side, to resolve the conflict
// Whe should update the metadatas correctly
if (isUpdated || isInserted)
{
using (var metadataCommand = syncAdapter.GetCommand(commandType))
{
// getting the row updated from server
var dmTableRow = syncAdapter.GetRow(row);
row = dmTableRow.Rows[0];
// Deriving Parameters
syncAdapter.SetCommandParameters(commandType, metadataCommand);
// Set the id parameter
syncAdapter.SetColumnParametersValues(metadataCommand, row);
var version = row.RowState == DmRowState.Deleted ? DmRowVersion.Original : DmRowVersion.Current;
Guid?create_scope_id = row["create_scope_id"] != DBNull.Value ? (Guid?)row["create_scope_id"] : null;
long createTimestamp = row["create_timestamp", version] != DBNull.Value ? Convert.ToInt64(row["create_timestamp", version]) : 0;
// The trick is to force the row to be "created before last sync"
// Even if we just inserted it
// to be able to get the row in state Updated (and not Added)
row["create_scope_id"] = create_scope_id;
row["create_timestamp"] = fromScopeLocalTimeStamp - 1;
// Update scope id is set to server side
Guid?update_scope_id = row["update_scope_id"] != DBNull.Value ? (Guid?)row["update_scope_id"] : null;
long updateTimestamp = row["update_timestamp", version] != DBNull.Value ? Convert.ToInt64(row["update_timestamp", version]) : 0;
row["update_scope_id"] = null;
row["update_timestamp"] = updateTimestamp;
// apply local row, set scope.id to null becoz applied locally
var rowsApplied = syncAdapter.InsertOrUpdateMetadatas(metadataCommand, row, null);
if (!rowsApplied)
{
throw new Exception("No metadatas rows found, can't update the server side");
}
}
}
}
finalRow = isMergeAction ? row : conflict.LocalRow;
// We don't do anything on the local provider, so we do not need to return a +1 on syncConflicts count
return(ChangeApplicationAction.Continue, 0, finalRow);
}
return(ChangeApplicationAction.Rollback, 0, finalRow);
}
// We gonna apply with force the line
if (conflictApplyAction == ApplyAction.RetryWithForceWrite)
{
if (conflict.RemoteRow == null)
{
// TODO : Should Raise an error ?
return(ChangeApplicationAction.Rollback, 0, finalRow);
}
bool operationComplete = false;
// create a localscope to override values
var localScope = new ScopeInfo {
Name = scope.Name, Timestamp = fromScopeLocalTimeStamp
};
DbCommandType commandType = DbCommandType.InsertMetadata;
bool needToUpdateMetadata = true;
switch (conflict.Type)
{
// Remote source has row, Local don't have the row, so insert it
case ConflictType.RemoteUpdateLocalNoRow:
case ConflictType.RemoteInsertLocalNoRow:
operationComplete = syncAdapter.ApplyInsert(conflict.RemoteRow, localScope, true);
commandType = DbCommandType.InsertMetadata;
break;
// Conflict, but both have delete the row, so nothing to do
case ConflictType.RemoteDeleteLocalDelete:
case ConflictType.RemoteDeleteLocalNoRow:
operationComplete = true;
needToUpdateMetadata = false;
break;
// The remote has delete the row, and local has insert or update it
// So delete the local row
case ConflictType.RemoteDeleteLocalUpdate:
case ConflictType.RemoteDeleteLocalInsert:
operationComplete = syncAdapter.ApplyDelete(conflict.RemoteRow, localScope, true);
commandType = DbCommandType.UpdateMetadata;
break;
// Remote insert and local delete, sor insert again on local
// but tracking line exist, so make an update on metadata
case ConflictType.RemoteInsertLocalDelete:
case ConflictType.RemoteUpdateLocalDelete:
operationComplete = syncAdapter.ApplyInsert(conflict.RemoteRow, localScope, true);
commandType = DbCommandType.UpdateMetadata;
break;
// Remote insert and local insert/ update, take the remote row and update the local row
case ConflictType.RemoteUpdateLocalInsert:
case ConflictType.RemoteUpdateLocalUpdate:
case ConflictType.RemoteInsertLocalInsert:
case ConflictType.RemoteInsertLocalUpdate:
operationComplete = syncAdapter.ApplyUpdate(conflict.RemoteRow, localScope, true);
commandType = DbCommandType.UpdateMetadata;
break;
case ConflictType.RemoteCleanedupDeleteLocalUpdate:
case ConflictType.ErrorsOccurred:
return(ChangeApplicationAction.Rollback, 0, finalRow);
}
if (needToUpdateMetadata)
{
using (var metadataCommand = syncAdapter.GetCommand(commandType))
{
// Deriving Parameters
syncAdapter.SetCommandParameters(commandType, metadataCommand);
// force applying client row, so apply scope.id (client scope here)
var rowsApplied = syncAdapter.InsertOrUpdateMetadatas(metadataCommand, conflict.RemoteRow, scope.Id);
if (!rowsApplied)
{
throw new Exception("No metadatas rows found, can't update the server side");
}
}
}
finalRow = conflict.RemoteRow;
//After a force update, there is a problem, so raise exception
if (!operationComplete)
{
var ex = $"Can't force operation for applyType {syncAdapter.ApplyType}";
finalRow = null;
return(ChangeApplicationAction.Continue, 0, finalRow);
}
// tableProgress.ChangesApplied += 1;
return(ChangeApplicationAction.Continue, 1, finalRow);
}
return(ChangeApplicationAction.Rollback, 0, finalRow);
}