Use a different Date data type

PLEASE backup your database before testing this commit, and report any
migration issue.

In postgresql, we use timestamp with timezone.
In sqlite3 we use REAL (the date is expressed as julianday)

This requires a migration of the muclogline_ table:
In postgresql it’s pretty simple, we convert all the integer into timestamps

With sqlite3, we actually rename the table, create the new one with the
correct type, then copy everything to the new table, with a conversion
function for the Date_ column, and then we delete the old table.

fix #3343

src/xmpp/biboumi_component.cpp

@@ -808,7 +808,7 @@ void BiboumiComponent::send_archived_message(const Database::MucLogLine& log_lin
 
     XmlSubNode delay(forwarded, "delay");
     delay["xmlns"] = DELAY_NS;
-    delay["stamp"] = utils::to_string(log_line.col<Database::Date>());
+    delay["stamp"] = log_line.col<Database::Date>().to_string();
 
     XmlSubNode submessage(forwarded, "message");
     submessage["xmlns"] = CLIENT_NS;

src/xmpp/xmpp_component.cpp

@@ -399,7 +399,7 @@ void XmppComponent::send_muc_message(const std::string& muc_name, const std::str
 }
 
 #ifdef USE_DATABASE
-void XmppComponent::send_history_message(const std::string& muc_name, const std::string& nick, const std::string& body_txt, const std::string& jid_to, Database::time_point::rep timestamp)
+void XmppComponent::send_history_message(const std::string& muc_name, const std::string& nick, const std::string& body_txt, const std::string& jid_to, const DateTime& timestamp)
 {
   Stanza message("message");
   message["to"] = jid_to;
@@ -417,7 +417,7 @@ void XmppComponent::send_history_message(const std::string& muc_name, const std:
     XmlSubNode delay(message, "delay");
     delay["xmlns"] = DELAY_NS;
     delay["from"] = muc_name + "@" + this->served_hostname;
-    delay["stamp"] = utils::to_string(timestamp);
+    delay["stamp"] = timestamp.to_string();
   }
 
   this->send_stanza(message);

src/xmpp/xmpp_component.hpp

@@ -6,6 +6,7 @@
 #include <network/tcp_client_socket_handler.hpp>
 #include <database/database.hpp>
 #include <xmpp/xmpp_parser.hpp>
+#include <utils/datetime.hpp>
 #include <xmpp/body.hpp>
 
 #include <unordered_map>
@@ -141,7 +142,7 @@ public:
    * Send a message, with a <delay/> element, part of a MUC history
    */
   void send_history_message(const std::string& muc_name, const std::string& nick, const std::string& body,
-                            const std::string& jid_to, Database::time_point::rep timestamp);
+                            const std::string& jid_to, const DateTime& timestamp);
 #endif
   /**
    * Send an unavailable presence for this nick