[10970] Implement mass mail send infrastructure.

It expected to be used in 2 case: some gameevent must send mails at start/end,
and this can be useful in game commands. Both case wil implemented in later commits.

* New MassMailMgr can accept tasks for send mass mails in safe way for map update threads context/etc.
* It work in way:
   - By provided race mask or more generic SQL query string in async query selected affected characters
   - At query result ready at next world tick update in safe common part of tick code some from mails
     from queued mas mail tasks send.
   - Amount mails limited MassMailer.SendPerTick confir option (10 by default). This done for prevent
     high server load/lags at send too many mails in one tick (mail send all existed characters in DB
     who match to seelction criteria)
   - Manager not persistant for server shutdowns so any not send mails in queue lost at shutdown.
     But with default setting 10K mail send in 20 secs (10000/50/10). Adding more safe execution
     for this case will make related code lot more slow and req. many DB tables and code support.

src/game/MassMailMgr.cpp

@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2005-2011 MaNGOS <http://getmangos.com/>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/**
+ * @addtogroup mailing
+ * @{
+ *
+ * @file MassMailMgr.cpp
+ * This file contains the the code needed for MaNGOS to handle mass mails send in safe and perfomence not affecting way.
+ *
+ */
+
+#include "MassMailMgr.h"
+#include "Policies/SingletonImp.h"
+#include "Database/DatabaseEnv.h"
+#include "Database/DatabaseImpl.h"
+#include "SharedDefines.h"
+#include "World.h"
+#include "ObjectMgr.h"
+
+INSTANTIATE_SINGLETON_1(MassMailMgr);
+
+void MassMailMgr::AddMassMailTask(MailDraft* mailProto, MailSender sender, uint32 raceMask)
+{
+    if (RACEMASK_ALL_PLAYABLE & ~raceMask)                  // have races not included in mask
+    {
+        std::ostringstream ss;
+        ss << "SELECT guid FROM characters WHERE (1 << (race - 1)) & " << raceMask << " AND deleteDate IS NULL";
+        AddMassMailTask(mailProto, sender, ss.str().c_str());
+    }
+    else
+        AddMassMailTask(mailProto, sender, "SELECT guid FROM characters WHERE deleteDate IS NULL");
+}
+
+struct MassMailerQueryHandler
+{
+    void HandleQueryCallback(QueryResult * result, MailDraft* mailProto, MailSender sender)
+    {
+        if (!result)
+            return;
+
+        MassMailMgr::ReceiversList& recievers = sMassMailMgr.AddMassMailTask(mailProto, sender);
+
+        do
+        {
+            Field *fields = result->Fetch();
+            recievers.insert(fields[0].GetUInt32());
+
+        } while (result->NextRow());
+        delete result;
+    }
+} massMailerQueryHandler;
+
+void MassMailMgr::AddMassMailTask(MailDraft* mailProto, MailSender sender, char const* query)
+{
+    CharacterDatabase.AsyncPQuery(&massMailerQueryHandler, &MassMailerQueryHandler::HandleQueryCallback, mailProto, sender, query);
+}
+
+void MassMailMgr::Update()
+{
+    if (m_massMails.empty())
+        return;
+
+    uint32 maxcount = sWorld.getConfig(CONFIG_UINT32_MASS_MAILER_SEND_PER_TICK);
+
+    do
+    {
+        MassMail& task = m_massMails.front();
+
+        while (!task.m_recivers.empty() && maxcount > 0)
+        {
+            uint32 receiver_lowguid = *task.m_recivers.begin();
+            task.m_recivers.erase(task.m_recivers.begin());
+
+            ObjectGuid receiver_guid = ObjectGuid(HIGHGUID_PLAYER, receiver_lowguid);
+            Player *receiver = sObjectMgr.GetPlayer(receiver_guid);
+
+            // last case. can be just send
+            if (task.m_recivers.empty())
+            {
+                // prevent mail return
+                task.m_protoMail->SendMailTo(MailReceiver(receiver, receiver_guid), task.m_sender, MAIL_CHECK_MASK_RETURNED);
+
+                --maxcount;
+                break;
+            }
+
+            // need clone draft
+            MailDraft draft;
+            draft.CloneFrom(*task.m_protoMail);
+
+            // prevent mail return
+            draft.SendMailTo(MailReceiver(receiver, receiver_guid), task.m_sender, MAIL_CHECK_MASK_RETURNED);
+
+            --maxcount;
+        }
+
+        if (task.m_recivers.empty())
+            m_massMails.pop_front();
+    }
+    while(!m_massMails.empty() && maxcount > 0);
+}
+
+void MassMailMgr::GetStatistic(uint32& tasks, uint32& mails, uint32& needTime) const
+{
+    tasks = m_massMails.size();
+
+    uint32 mailsCount = 0;
+    for (MassMailList::const_iterator mailItr = m_massMails.begin(); mailItr != m_massMails.end(); ++mailItr)
+        mailsCount += mailItr->m_recivers.size();
+
+    mails = mailsCount;
+
+    // 50 msecs is tick length
+    needTime = 50 * mailsCount / sWorld.getConfig(CONFIG_UINT32_MASS_MAILER_SEND_PER_TICK) / IN_MILLISECONDS;
+}
+
+
+/*! @} */