public bool ShouldCreateNewItemForConflict(RecordItemChange change, Exception ex)
{
ServerException se = ex as ServerException;
if (se != null)
{
return (this.IsItemKeyNotFound(se)); // Sometimes when the item is really missing, we get this error..
}
return false;
}
public bool ShouldRetryCommit(RecordItemChange change, Exception ex)
{
if (this.IsClientValidationError(ex) ||
this.IsSerializationError(ex) ||
!this.IsHttpError(ex)
)
{
return false;
}
if (this.MaxAttemptsPerChange > 0 && change.Attempt >= this.MaxAttemptsPerChange)
{
return false;
}
return true;
}
public static int Compare(RecordItemChange x, RecordItemChange y)
{
int cmp = x.Timestamp.CompareTo(y.Timestamp);
if (cmp == 0)
{
cmp = x.ItemID.CompareTo(y.ItemID);
}
return cmp;
}
internal async Task OnChangeCommittedAsync(RecordItemChange change)
{
if (change.ChangeType != RecordItemChangeType.Put)
{
return;
}
try
{
SynchronizedType sType = await this.GetAsync(change.TypeID);
await sType.OnPutCommittedAsync(change);
this.TypeUpdated.SafeInvokeInUIThread(this, change.TypeID);
}
catch
{
}
}
internal async Task SaveChangeAsync(RecordItemChange change)
{
await m_changeStore.PutAsync(change.ItemID, change);
}
async Task<bool> CommitPutAsync(RecordItemChange change, long itemLockID)
{
IItemDataTyped item = await m_store.Local.GetByIDAsync(change.ItemID);
if (item == null)
{
return false;
}
change.LocalData = item;
if (item.Key.IsLocal)
{
await this.CommitNewAsync(change);
}
else
{
await this.CommitUpdateAsync(change);
}
//
// Refetch the item from HealthVault, to get updated dates etc...
//
await this.RefreshItemAsync(change, itemLockID);
return true;
}
void NotifyCommitFailed(RecordItemChange change)
{
Debug.WriteLine("Change Commit failed {0}", change);
this.CommitFailed.SafeInvokeInUIThread(this, change);
}
async Task UpdateChangeAttemptCount(RecordItemChange change)
{
try
{
change.Attempt++;
await m_changeTable.SaveChangeAsync(change);
}
catch(Exception ex)
{
this.NotifyError(ex);
}
}
async Task NotifySynchronizedTypesAsync(RecordItemChange change)
{
try
{
if (this.SynchronizedTypes != null)
{
await this.SynchronizedTypes.OnChangeCommittedAsync(change);
}
}
catch
{
}
}
async Task RefreshItemAsync(RecordItemChange change, long lockID)
{
change.UpdatedItem = null;
try
{
change.UpdatedItem = await m_store.RemoteStore.GetItemAsync(change.UpdatedKey, m_store.SectionsToFetch);
}
catch(Exception ex)
{
this.NotifyError(ex);
}
}
async Task<bool> DetectDuplicateAsync(RecordItemChange change)
{
IList<RecordItem> results = await this.LookupCommitsInRemoteStoreAsync(change.ChangeID);
if (results.IsNullOrEmpty())
{
return false;
}
change.UpdatedKey = results[0].Key;
return true;
}
async Task CommitRemoveAsync(RecordItemChange change, long itemLockID)
{
try
{
if (change.Key.IsLocal)
{
return;
}
await m_store.RemoteStore.RemoveItemAsync(change.Key);
}
catch(ServerException se)
{
if (!m_errorHandler.IsItemKeyNotFound(se))
{
throw;
}
}
}
async Task CommitNewAsync(RecordItemChange change)
{
Debug.Assert(change.HasLocalData);
change.UpdatedKey = await m_store.RemoteStore.NewAsync(change.LocalData);
}
async Task CommitUpdateAsync(RecordItemChange change)
{
Debug.Assert(change.HasLocalData);
if (await this.DetectDuplicateAsync(change))
{
// Already applied this change
return;
}
try
{
change.UpdatedKey = await m_store.RemoteStore.PutAsync(change.LocalData);
return;
}
catch (Exception ex)
{
if (!m_errorHandler.ShouldCreateNewItemForConflict(change, ex))
{
//
// Let the calling function decide how to handle all other scenarios
//
throw;
}
}
//
// Conflict resolution is simple. We don't want to lose data. If the data on the server changed from underneath us,
// we will write this item as a NEW one, since the user did actually take the trouble to create the entry
//
await this.CommitNewAsync(change);
}
public static RecordItemChange UpdateChange(string typeID, ItemKey key, RecordItemChangeType changeType, RecordItemChange existingChange)
{
if (existingChange == null)
{
return new RecordItemChange(typeID, key, changeType);
}
if (existingChange.ChangeType == RecordItemChangeType.Remove && changeType == RecordItemChangeType.Put)
{
// Can't put an item already marked for deletion
throw new StoreException(StoreErrorNumber.ItemAlreadyDeleted);
}
if (existingChange.TypeID != typeID)
{
// Defensive code. Should never happen
throw new StoreException(StoreErrorNumber.TypeIDMismatch);
}
existingChange.InitChange(key, changeType);
return existingChange;
}
void NotifyCommitSuccess(RecordItemChange change)
{
Debug.WriteLine("Change Committed {0}", change);
this.CommitSuccess.SafeInvokeInUIThread(this, change);
}
internal async Task OnPutCommittedAsync(RecordItemChange change)
{
Debug.Assert(change.HasUpdatedItem || change.HasLocalData);
RecordItem updatedItem = change.UpdatedItem;
if (updatedItem == null)
{
updatedItem = change.LocalData.Item;
updatedItem.Key = change.UpdatedKey;
}
await this.Data.Local.PutItemAsync(updatedItem);
await this.UpdateKeyAsync(change.ItemID, updatedItem);
}
// Assumes that you've acquire the item lock earlier!
// Critical that the item lock be acquired
async Task<bool> CommitChange(RecordItemChange change, long itemLockID)
{
bool dequeue = false;
try
{
await this.UpdateChangeAttemptCount(change);
if (change.ChangeType == RecordItemChangeType.Remove)
{
await this.CommitRemoveAsync(change, itemLockID);
}
else
{
if (await this.CommitPutAsync(change, itemLockID))
{
await this.NotifySynchronizedTypesAsync(change);
}
}
this.NotifyCommitSuccess(change);
dequeue = true;
}
catch (Exception ex)
{
if (m_errorHandler.IsHaltingError(ex))
{
this.NotifyError(ex);
return false; // Stop processing items right away because of major Halting errors, such as Network
}
if (m_errorHandler.ShouldRetryCommit(change, ex))
{
// Leave the change in the commit queue. try again later
this.NotifyError(ex);
}
else
{
this.NotifyCommitFailed(change);
dequeue = true;
}
}
if (dequeue)
{
await m_changeTable.RemoveChangeAsync(change.ItemID);
}
return true;
}
