public void UpdateJsonSyncingFeed(long groupId, JsonSyncingFeed state)
{
DbSyncingFeed row = new DbSyncingFeed();
row.FeedId = groupId;
// Update the aggregated properties
row.LastUpdateUtc = state.LastUpdateUtc;
row.LastCheckNewUtc = state.LastCheckNewUtc;
row.ReachedEmptyResult = state.ReachedEmptyResult;
row.HasSpanGaps = state.HasSpanGaps;
row.Json = SQLiteJsonConverter.SaveToJson(state);
SyncingFeeds.InsertRecord(row, SQLiteConflictResolution.Replace);
}
void UpgradeDatabase()
{
// Validate the database state
int coreDbVersion = archiveDb.GetObjectVersion("Core");
bool inactiveArchiveDb = this.archiveDb.IsInactive();
if (coreDbVersion == CurrentCoreDbVersion)
{
return;
}
if (coreDbVersion > CurrentCoreDbVersion)
{
throw new UnsupportedDatabaseVersionException("Core", coreDbVersion, CurrentCoreDbVersion);
}
if (inactiveArchiveDb)
{
if (coreDbVersion < MinimumUpgradeableCoreDbVersionWithoutArchiveDb)
{
// The database cannot be upgraded because the ArchiveDB is missing,
// e.g. because the data was imported using CsvDumpLoader
throw new UnsupportedDatabaseVersionException("Core", coreDbVersion, CurrentCoreDbVersion);
}
}
if (coreDbVersion < MinimumUpgradeableCoreDbVersion)
{
RebuildDatabase(coreDbVersion);
return;
}
var args2 = new SQLiteDataContextUpgradeEventArgs("Core",
"For a large database, the upgrade may take a while. Please be patient.",
coreDbVersion, CurrentCoreDbVersion);
OnBeforeUpgrade(args2);
if (args2.CancelUpgrade)
{
throw new DatabaseUpgradeCanceledException("Core");
}
var startTime = DateTime.Now;
Debug.WriteLine("BEGIN UPGRADE CORE DATABASE");
RebuildableTable alreadyRebuiltTables = RebuildableTable.None;
// Upgrade 1004 -> 1005
if (coreDbVersion < 1005)
{
Debug.Assert(coreDbVersion == 1004);
using (var transaction = this.BeginTransaction())
{
string sqlTemplate = @"
ALTER TABLE [{0}]
ADD COLUMN [ChangeNumber] INTEGER NOT NULL DEFAULT -1;
-- Ensure ChangeNumber is unique
UPDATE [{0}]
SET [ChangeNumber] = [RowId];
CREATE UNIQUE INDEX [{0}_Index0] ON [{0}] ([ChangeNumber]);
CREATE TRIGGER [{0}_ChangeNumberTrigger0] AFTER INSERT ON [{0}]
BEGIN
UPDATE [{0}]
SET [ChangeNumber] = (SELECT MAX([ChangeNumber]) FROM [{0}] LIMIT 1)+1
WHERE ROWID = NEW.ROWID;
END;
CREATE TRIGGER [{0}_ChangeNumberTrigger1] AFTER UPDATE ON [{0}]
BEGIN
UPDATE [{0}]
SET [ChangeNumber] = (SELECT MAX([ChangeNumber]) FROM [{0}] LIMIT 1)+1
WHERE ROWID = NEW.ROWID;
END;
";
foreach (string tableName in new string[] { "GroupStates", "MessageStates" })
{
string sql = string.Format(sqlTemplate, tableName);
this.Mapper.ExecuteNonQuery(sql);
}
this.RebuildTablesIfNeeded(
RebuildableTable.Groups
| RebuildableTable.Messages
| RebuildableTable.Users,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1005);
transaction.Commit();
coreDbVersion = 1005;
}
}
// Upgrade 1005 -> 1006
if (coreDbVersion < 1006)
{
Debug.Assert(coreDbVersion == 1005);
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added CurrentUserId column
RebuildableTable.Properties,
ref alreadyRebuiltTables
);
// Group name changed in this version
InitVirtualGroups();
archiveDb.SetObjectVersion("Core", 1006);
transaction.Commit();
coreDbVersion = 1006;
}
}
// Upgrade 1006 -> 1007
if (coreDbVersion < 1007)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added Conversations table
RebuildableTable.Conversations
// Added ConversationId column
| RebuildableTable.Messages,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1007);
transaction.Commit();
coreDbVersion = 1007;
}
}
// Upgrade 1007 -> 1008
if (coreDbVersion < 1008)
{
using (var transaction = this.BeginTransaction())
{
// Added "(All Company)" group
InitVirtualGroups();
GroupStates.InsertRecord(new DbGroupState()
{
GroupId = YamsterGroup.AllCompanyGroupId,
ShowInYamster = true,
ShouldSync = false,
TrackRead = true
});
archiveDb.SetObjectVersion("Core", 1008);
transaction.Commit();
coreDbVersion = 1008;
}
}
// Upgrade 1008 -> 1009
if (coreDbVersion < 1009)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Replaced DbConversation.ParticipantsJson with ParticipantUserIds
RebuildableTable.Conversations
// Added LikingUserIds and NotifiedUserIds
| RebuildableTable.Messages,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1009);
transaction.Commit();
coreDbVersion = 1009;
}
}
// Upgrade 1009 -> 1010
if (coreDbVersion < 1010)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added CurrentNetworkId, FollowYamsterLastAskedUtc, and FollowYamsterState
RebuildableTable.Properties,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1010);
transaction.Commit();
coreDbVersion = 1010;
}
}
// Upgrade 1010 -> 1011
if (coreDbVersion < 1011)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Fixed issue where liking users weren't being extracted from the Messages
// table into the Users table
RebuildableTable.Messages,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1011);
transaction.Commit();
coreDbVersion = 1011;
}
}
// Upgrade 1011 -> 1012
if (coreDbVersion < 1012)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added SyncInbox
RebuildableTable.Properties
// These tables are new
| RebuildableTable.SyncingFeeds | RebuildableTable.SyncingThreads,
ref alreadyRebuiltTables
);
// This could have been lost if the ArchiveDb was regenerated
if (this.Mapper.QueryScalar <long>(
"SELECT COUNT(*) FROM sqlite_master WHERE name ='ArchiveSyncState' and type='table'") > 0)
{
var syncStates = this.Mapper.Query <V1011_DbArchiveSyncState>(
"SELECT [GroupId], [Json] FROM [ArchiveSyncState]");
foreach (var syncState in syncStates)
{
var jsonGroupState = SQLiteJsonConverter.LoadFromJson <V1011_MessagePullerGroupState>(syncState.Json);
// Build a DbSyncingFeed record
var syncingFeed = new JsonSyncingFeed()
{
ReachedEmptyResult = jsonGroupState.ReachedEmptyResult,
SpanCyclesSinceCheckNew = jsonGroupState.SpanCyclesSinceCheckNew,
LastUpdateUtc = jsonGroupState.LastUpdateUtc,
LastCheckNewUtc = jsonGroupState.LastCheckNewUtc
};
foreach (var span in jsonGroupState.Spans)
{
syncingFeed.AddSpan(new JsonMessagePullerSpan()
{
StartTimeUtc = span.StartTimeUtc,
StartMessageId = span.StartMessageId,
EndMessageId = span.EndMessageId
}
);
}
this.UpdateJsonSyncingFeed(syncState.GroupId, syncingFeed);
// Build DbSyncingThread records
foreach (var gappedThread in jsonGroupState.GappedThreads)
{
var syncingThread = new DbSyncingThread()
{
ThreadId = gappedThread.ThreadId,
FeedId = syncState.GroupId,
LastPulledMessageId = gappedThread.LastPulledMessageId,
StopMessageId = gappedThread.StopMessageId,
RetryCount = gappedThread.RetryCount
};
this.SyncingThreads.InsertRecord(syncingThread);
}
}
this.Mapper.ExecuteNonQuery("DROP TABLE [ArchiveSyncState]");
}
archiveDb.SetObjectVersion("Core", 1012);
transaction.Commit();
coreDbVersion = 1012;
}
}
// Upgrade 1012 -> 1013
if (coreDbVersion < 1013)
{
using (var transaction = this.BeginTransaction())
{
this.Mapper.CreateTable(this.ThreadStates);
// Make sure we have DbThreadState records for each thread
foreach (var result in this.Mapper.Query <DbInt64Result>(
"SELECT DISTINCT [ThreadId] AS [Value] FROM [Messages]"))
{
this.ThreadStates.InsertRecord(new DbThreadState()
{
ThreadId = result.Value
},
SQLiteConflictResolution.Ignore);
}
archiveDb.SetObjectVersion("Core", 1013);
transaction.Commit();
coreDbVersion = 1013;
}
}
// Upgrade 1013 -> 1014
if (coreDbVersion < 1014)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added DbMessage.MessageIdRepliedTo
RebuildableTable.Messages,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1014);
transaction.Commit();
coreDbVersion = 1014;
}
}
// Upgrade 1014 -> 1015
if (coreDbVersion < 1015)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added DbMessage.AttachmentWidth/AttachmentHeight
RebuildableTable.Messages,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1015);
transaction.Commit();
coreDbVersion = 1015;
}
}
// Upgrade 1015 -> 1016
if (coreDbVersion < 1016)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added DbUser.Alias
RebuildableTable.Users,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1016);
transaction.Commit();
coreDbVersion = 1016;
}
}
// Upgrade 1016 -> 1017
if (coreDbVersion < 1017)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Removed FollowYamsterLastAskedUtc and FollowYamsterState
RebuildableTable.Properties,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1017);
transaction.Commit();
coreDbVersion = 1017;
}
}
// Upgrade 1017 -> 1018
if (coreDbVersion < 1018)
{
using (var transaction = this.BeginTransaction())
{
this.Mapper.ExecuteNonQuery(@"ALTER TABLE [MessageStates] ADD COLUMN [Deleted] INTEGER NOT NULL DEFAULT 0");
this.RebuildTablesIfNeeded(
// Added DbMessage.MessageType
RebuildableTable.Messages,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1018);
transaction.Commit();
coreDbVersion = 1018;
}
}
// Upgrade 1018 -> 1019
if (coreDbVersion < 1019)
{
using (var transaction = this.BeginTransaction())
{
this.RebuildTablesIfNeeded(
// Added DbUser.Alias
RebuildableTable.Users,
ref alreadyRebuiltTables
);
archiveDb.SetObjectVersion("Core", 1019);
transaction.Commit();
coreDbVersion = 1019;
}
}
if (coreDbVersion != CurrentCoreDbVersion)
{
// This is a program bug
throw new InvalidOperationException("Upgrade failed");
}
var totalTime = DateTime.Now - startTime;
Debug.WriteLine("END UPGRADE CORE DATABASE: {0} secs processing time", totalTime.TotalSeconds);
OnAfterUpgrade();
}
async Task ProcessSpanAsync(JsonSyncingFeed syncingFeed, bool forceCheckNew)
{
this.appContext.RequireForegroundThread();
long feedId = syncingFeed.FeedId;
DateTime queryUtc = DateTime.UtcNow;
bool checkNew = forceCheckNew ||
syncingFeed.Spans.Count < 1 ||
(syncingFeed.Spans.Count == 1 && syncingFeed.ReachedEmptyResult);
long?olderThan = null;
if (checkNew)
{
syncingFeed.SpanCyclesSinceCheckNew = 0;
syncingFeed.LastCheckNewUtc = queryUtc;
}
else
{
++syncingFeed.SpanCyclesSinceCheckNew;
// Work backwards from the most recent gap
var lastSpan = syncingFeed.Spans.Last();
olderThan = lastSpan.StartMessageId;
}
syncingFeed.LastUpdateUtc = queryUtc;
if (CallingService != null)
{
CallingService(this, new MessagePullerCallingServiceEventArgs(feedId, null));
}
JsonMessageEnvelope envelope;
try
{
// Perform a REST query like this:
// https://www.yammer.com/example.com/api/v1/messages/in_group/3.json?threaded=extended&older_than=129
envelope = await yamsterApi.GetMessagesInFeedAsync(feedId, olderThan);
this.appContext.RequireForegroundThread();
}
catch (RateLimitExceededException ex)
{
yamsterApi.NotifyRateLimitExceeded();
OnError(ex);
return;
}
catch (WebException ex)
{
var response = ex.Response as HttpWebResponse;
if (response != null)
{
if (response.StatusCode == HttpStatusCode.NotFound && syncingFeed.GroupState != null)
{
// The group does not exist; disable further syncing for it and report
// a more specific error
DbGroupState groupState = syncingFeed.GroupState;
groupState.ShouldSync = false;
yamsterCoreDb.GroupStates.InsertRecord(groupState, SQLiteConflictResolution.Replace);
OnError(new YamsterFailedSyncException(feedId, ex));
return;
}
}
// A general error has occurred
yamsterApi.BackOff();
OnError(ex);
return;
}
var newSpan = new JsonMessagePullerSpan();
newSpan.StartMessageId = long.MaxValue;
newSpan.StartTimeUtc = DateTime.MaxValue;
newSpan.EndMessageId = long.MinValue;
using (var transaction = yamsterArchiveDb.BeginTransaction())
{
WriteReferencesToDb(envelope.References, queryUtc);
foreach (var threadStarter in envelope.Messages)
{
// Clean up any corrupted data
if (yamsterCoreDb.SyncingThreads
.DeleteRecords("WHERE [ThreadId] = " + threadStarter.ThreadId) > 0)
{
Debug.WriteLine("MessagePuller: WARNING: Removed unexpected sync state for thread ID={0}",
threadStarter.ThreadId);
}
JsonMessage[] extendedMessages;
// Note that ThreadedExtended is indexed by thread ID, not message ID
if (!envelope.ThreadedExtended.TryGetValue(threadStarter.ThreadId, out extendedMessages))
{
extendedMessages = new JsonMessage[0];
}
// Update the span bounds
long latestMessageIdInThread;
DateTime latestMessageTimeInThread;
if (extendedMessages.Length > 0)
{
latestMessageIdInThread = extendedMessages.Max(x => x.Id);
latestMessageTimeInThread = extendedMessages.Max(x => x.Created);
}
else
{
latestMessageIdInThread = threadStarter.Id;
latestMessageTimeInThread = threadStarter.Created;
}
newSpan.StartMessageId = Math.Min(newSpan.StartMessageId, latestMessageIdInThread);
if (latestMessageTimeInThread < newSpan.StartTimeUtc)
{
newSpan.StartTimeUtc = latestMessageTimeInThread;
}
newSpan.EndMessageId = Math.Max(newSpan.EndMessageId, latestMessageIdInThread);
WriteMessageToDb(threadStarter, queryUtc);
// NOTE: The thread is presumed to be contiguous at this point.
// This is guaranteed to return at least threadStarter.Id written above
long latestMessageInDb = yamsterArchiveDb.Mapper.QueryScalar <long>(
"SELECT MAX(Id) FROM [" + this.yamsterArchiveDb.ArchiveMessages.TableName
+ "] WHERE ThreadId = " + threadStarter.ThreadId.ToString());
// There are two scenarios where we can prove that there is no gap,
// i.e. that we already have all the messages for the thread.
// NOTE: Originally we assumed there was no gap if extendedMessages.Length<2,
// but a counterexample was found.
bool gapped = true;
// For debugging -- skip pulling most messages to accumulate threads faster
#if false
if ((threadStarter.ThreadId & 31) != 0)
{
gapped = false;
}
#endif
// Scenario 1: Does the envelope contain the complete thread?
var threadReference = envelope.References
.OfType <ThreadReferenceJson>()
.Where(x => x.Id == threadStarter.ThreadId)
.FirstOrDefault();
if (threadReference != null)
{
// (+1 for threadStarter)
if (extendedMessages.Length + 1 == threadReference.Stats.MessagesCount)
{
// This criteria should work, but I found cases where Yammer's counter is incorrect
#if false
// The envelope contains the complete thread
gapped = false;
#endif
}
}
else
{
// This should never happen, but if it does it's okay if we wrongly assume
// the thread is gapped
Debug.Assert(false);
}
// Scenario 2: Do the envelope messages overlap with the database's version of the thread?
if (gapped && extendedMessages.Length > 0)
{
long extendedStartId = extendedMessages.Min(x => x.Id);
if (latestMessageInDb >= extendedStartId)
{
// Yes, the messages overlap
gapped = false;
}
}
if (gapped)
{
var gappedThread = new DbSyncingThread();
gappedThread.FeedId = feedId;
gappedThread.ThreadId = threadStarter.ThreadId;
gappedThread.StopMessageId = latestMessageInDb;
// NOTE: In a static database, it would be most efficient to call
// WriteMessageToDb() for the extendedMessages that we already received
// and pick up with LastPulledMessageId=extendedStartId.
// However, if we assume people are actively posting in Yammer, it's
// better to begin processing a gapped thread by querying for the absolute
// latest stuff, since a fair amount of time may have elapsed by the
// time we get around to doing the query.
gappedThread.LastPulledMessageId = null;
gappedThread.RetryCount = 0;
// A key violation should be impossible here since if there was a conflicting
// record, we deleted it above.
yamsterCoreDb.SyncingThreads.InsertRecord(gappedThread);
}
else
{
foreach (var extendedMessage in extendedMessages)
{
WriteMessageToDb(extendedMessage, queryUtc);
}
}
}
if (envelope.Messages.Length > 0)
{
if (olderThan.HasValue)
{
// If the Yammer result includes messages newer than what we asked
// for with olderThan, this is most likely a bug.
// NOTE: Skip this check for the Inbox feed, which seems to have minor
// overlap about 50% of the time. This issue wasn't observed in the Yammer web page,
// but that may be due to the additional filtering there for seen/unarchived.
if (feedId != YamsterGroup.InboxFeedId)
{
Debug.Assert(newSpan.EndMessageId < olderThan);
}
// If olderThan was specified, then the span actually covers anything
// up to that point in the history
newSpan.EndMessageId = olderThan.Value - 1;
}
// Now create a span corresponding to the range of messages we just received.
syncingFeed.AddSpan(newSpan);
}
else
{
syncingFeed.ReachedEmptyResult = true;
}
yamsterCoreDb.UpdateJsonSyncingFeed(feedId, syncingFeed);
if (feedId == YamsterGroup.InboxFeedId)
{
// For each GroupId in the messages that we wrote, make sure ShowInYamster = 1
string showInYamsterSql = string.Format(
@"UPDATE [GroupStates] SET [ShowInYamster] = 1"
+ " WHERE [GroupId] in ({0}) AND [ShowInYamster] <> 1",
string.Join(
", ",
envelope.Messages.Where(x => x.GroupId != null).Select(x => x.GroupId).Distinct()
)
);
yamsterCoreDb.Mapper.ExecuteNonQuery(showInYamsterSql);
// For each ThreadId in the messages that we wrote, mark it as appearing in the inbox
string seenInInboxSql = string.Format(
@"UPDATE [ThreadStates] SET [SeenInInboxFeed] = 1"
+ " WHERE [ThreadId] in ({0}) AND [SeenInInboxFeed] <> 1",
string.Join(
", ",
envelope.Messages.Select(x => x.ThreadId).Distinct()
)
);
yamsterCoreDb.Mapper.ExecuteNonQuery(seenInInboxSql);
}
transaction.Commit();
if (UpdatedDatabase != null)
{
UpdatedDatabase(this, EventArgs.Empty);
}
}
}
async Task ProcessAsync()
{
this.appContext.RequireForegroundThread();
if (!this.enabled)
{
return;
}
DateTime nowUtc = DateTime.UtcNow;
// Don't exceed the Yammer throttling limit. For a FreshenThread() request,
// we increase the priority.
if (!yamsterApi.IsSafeToRequest(increasedPriority: freshenThreadRequest != null))
{
return;
}
// Start by assuming we're not up to date, unless proven otherwise
UpToDate = false;
// 1. Is there a request to freshen a specific thread?
if (freshenThreadRequest != null)
{
var freshenedThread = yamsterCoreDb.SyncingThreads
.Query("WHERE ThreadId = " + freshenThreadRequest.Thread.ThreadId)
.FirstOrDefault();
if (freshenThreadRequest.State == FreshenThreadState.Queued)
{
freshenThreadRequest.SetState(FreshenThreadState.Processing);
// Is there already an existing gap for this thread?
if (freshenedThread != null)
{
// Yes, simply reopen it
freshenedThread.LastPulledMessageId = null;
}
else
{
// No, so create a new one
freshenedThread = new DbSyncingThread();
freshenedThread.FeedId = freshenThreadRequest.Thread.GroupId;
freshenedThread.ThreadId = freshenThreadRequest.Thread.ThreadId;
// NOTE: The thread is presumed to be contiguous at this point.
long latestMessageInDb = yamsterArchiveDb.Mapper.QueryScalar <long>(
"SELECT MAX(Id) FROM " + this.yamsterArchiveDb.ArchiveMessages.TableName
+ " WHERE ThreadId = " + freshenThreadRequest.Thread.ThreadId.ToString());
freshenedThread.StopMessageId = latestMessageInDb;
freshenedThread.LastPulledMessageId = null;
yamsterCoreDb.SyncingThreads.InsertRecord(freshenedThread);
}
}
if (freshenThreadRequest.State != FreshenThreadState.Processing)
{
// This should be impossible
freshenThreadRequest.SetError(new Exception("State machine error"));
freshenThreadRequest = null;
return;
}
await ProcessGappedThreadAsync(freshenedThread);
this.appContext.RequireForegroundThread();
return;
}
// 2. Are there any syncing threads? We must finish them before processing more spans
var syncingThread = yamsterCoreDb.SyncingThreads
.QueryAll()
.FirstOrDefault();
if (syncingThread != null)
{
// Start at the top of the list
await ProcessGappedThreadAsync(syncingThread);
this.appContext.RequireForegroundThread();
return;
}
// Get the list of subscribed feeds
List <DbGroupState> groupsToSync = yamsterCoreDb.GroupStates
.Query("WHERE ShouldSync").ToList();
bool forceCheckNew = false;
List <JsonSyncingFeed> syncingFeeds = groupsToSync
.Select(
groupState => {
var syncingFeed = yamsterCoreDb.GetJsonSyncingFeed(groupState.GroupId)
?? new JsonSyncingFeed();
syncingFeed.GroupState = groupState;
syncingFeed.FeedId = groupState.GroupId;
return(syncingFeed);
}
).ToList();
if (yamsterCoreDb.Properties.SyncInbox)
{
// The Inbox is not a real group, so it doesn't have a DbGroupState record.
var inboxSyncingFeed = yamsterCoreDb.GetJsonSyncingFeed(YamsterGroup.InboxFeedId)
?? new JsonSyncingFeed();
inboxSyncingFeed.GroupState = null;
inboxSyncingFeed.FeedId = YamsterGroup.InboxFeedId;
syncingFeeds.Insert(0, inboxSyncingFeed);
}
JsonSyncingFeed chosenSyncingFeed = null;
// 3. Should we interrupt work on the history and instead check for new messages?
if (Algorithm == MessagePullerAlgorithm.OptimizeReading)
{
TimeSpan longCheckNewDuration = TimeSpan.FromMinutes(7);
chosenSyncingFeed = syncingFeeds
// Choose a feed that wasn't synced recently, but only if it has already
// done some work on its history
.Where(x => x.SpanCyclesSinceCheckNew >= 2 &&
(nowUtc - x.LastCheckNewUtc) > longCheckNewDuration)
// Pick the feed that was synced least recently
.OrderBy(x => x.LastCheckNewUtc)
.FirstOrDefault();
if (chosenSyncingFeed != null)
{
forceCheckNew = true;
}
}
// 4. Are there any incomplete histories? If so, choose the feed who
// made the least progress syncing so far
if (chosenSyncingFeed == null)
{
// There are two kinds of feeds that need work:
// 1. If it has gaps in the spans
// 2. If we did not reach the beginning of the stream yet
var nextHistoricalFeed = syncingFeeds
.Where(x => x.HasSpanGaps || !x.ReachedEmptyResult)
.OrderByDescending(x => x.GetNextOlderThanTime())
.FirstOrDefault();
if (nextHistoricalFeed != null)
{
var time = nextHistoricalFeed.GetNextOlderThanTime();
if (time != DateTime.MaxValue) // don't show this degenerate value in the UI
{
HistoryProgress = time;
}
if (HistoryLimitDays > 0)
{
// If HistoryLimitDays is enabled, then don't pull threads that are
// older than the historyLimit
DateTime historyLimit = DateTime.Now.Date.Subtract(TimeSpan.FromDays(HistoryLimitDays));
if (nextHistoricalFeed.GetNextOlderThanTime() >= historyLimit)
{
chosenSyncingFeed = nextHistoricalFeed;
}
}
else
{
chosenSyncingFeed = nextHistoricalFeed;
}
}
}
// 5. If all the histories are complete, then check for new messages at periodic intervals
if (chosenSyncingFeed == null)
{
TimeSpan shortCheckNewDuration = TimeSpan.FromMinutes(3);
chosenSyncingFeed = syncingFeeds
// Don't sync more often than shortCheckNewDuration
.Where(x => (nowUtc - x.LastCheckNewUtc) > shortCheckNewDuration)
// Pick the feed that was synced least recently
.OrderBy(x => x.LastCheckNewUtc)
.FirstOrDefault();
if (chosenSyncingFeed != null)
{
forceCheckNew = true;
}
}
UpToDate = chosenSyncingFeed == null;
if (!UpToDate)
{
await ProcessSpanAsync(chosenSyncingFeed, forceCheckNew);
this.appContext.RequireForegroundThread();
}
else
{
Debug.WriteLine("Up to date.");
}
}