--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Framework/Loaders/OracleScheduler.h	Mon Dec 09 13:58:37 2019 +0100
@@ -0,0 +1,167 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2019 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero General Public License
+ * as published by the Free Software Foundation, either version 3 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
+ * Affero General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#pragma once
+
+#if !defined(ORTHANC_ENABLE_DCMTK)
+#  error The macro ORTHANC_ENABLE_DCMTK must be defined
+#endif
+
+#include "../Messages/IMessageEmitter.h"
+#include "../Messages/ObserverBase.h"
+#include "../Oracle/GetOrthancImageCommand.h"
+#include "../Oracle/GetOrthancWebViewerJpegCommand.h"
+#include "../Oracle/HttpCommand.h"
+#include "../Oracle/IOracle.h"
+#include "../Oracle/OracleCommandExceptionMessage.h"
+#include "../Oracle/OrthancRestApiCommand.h"
+#include "../Oracle/ReadFileCommand.h"
+
+#if ORTHANC_ENABLE_DCMTK == 1
+#  include "../Oracle/ParseDicomSuccessMessage.h"
+#endif
+
+namespace OrthancStone
+{
+  class OracleScheduler : public ObserverBase<OracleScheduler>
+  {
+  public:
+    static const int PRIORITY_HIGH = -1;
+    static const int PRIORITY_LOW = 100;
+  
+  private:
+    enum Priority
+    {
+      Priority_Low,
+      Priority_Standard,
+      Priority_High
+    };
+
+    class ReceiverPayload;
+    class ScheduledCommand;
+
+    typedef std::multimap<int, ScheduledCommand*>  Queue;
+
+    IOracle&  oracle_;
+    IMessageEmitter&  emitter_;
+    Queue          standardPriorityQueue_;
+    Queue          highPriorityQueue_;
+    Queue          lowPriorityQueue_;
+    unsigned int   maxHighPriorityCommands_;  // Used if priority <= PRIORITY_HIGH
+    unsigned int   maxStandardPriorityCommands_;
+    unsigned int   maxLowPriorityCommands_;  // Used if priority >= PRIORITY_LOW
+    unsigned int   activeHighPriorityCommands_;
+    unsigned int   activeStandardPriorityCommands_;
+    unsigned int   activeLowPriorityCommands_;
+    uint64_t       totalScheduled_;
+    uint64_t       totalProcessed_;
+
+    void ClearQueue(Queue& queue);
+
+    void RemoveReceiverFromQueue(Queue& queue,
+                                 boost::shared_ptr<IObserver> receiver);
+
+    void CheckInvariants() const;
+
+    void SpawnFromQueue(Queue& queue,
+                        Priority priority);
+
+    void SpawnCommands();
+
+    void RemoveActiveCommand(const ReceiverPayload& payload);
+
+    void Handle(const GetOrthancImageCommand::SuccessMessage& message);
+
+    void Handle(const GetOrthancWebViewerJpegCommand::SuccessMessage& message);
+
+    void Handle(const HttpCommand::SuccessMessage& message);
+
+    void Handle(const OrthancRestApiCommand::SuccessMessage& message);
+
+#if ORTHANC_ENABLE_DCMTK == 1
+    void Handle(const ParseDicomSuccessMessage& message);
+#endif
+
+    void Handle(const ReadFileCommand::SuccessMessage& message);
+
+    void Handle(const OracleCommandExceptionMessage& message);
+
+    OracleScheduler(IOracle& oracle,
+                    IMessageEmitter& emitter,
+                    unsigned int maxHighPriority,
+                    unsigned int maxStandardPriority,
+                    unsigned int maxLowPriority);
+    
+  public:
+    static boost::shared_ptr<OracleScheduler> Create(IOracle& oracle,
+                                                     IObservable& oracleObservable,
+                                                     IMessageEmitter& emitter)
+    {
+      return Create(oracle, oracleObservable, emitter, 1, 4, 1);
+    }
+
+    static boost::shared_ptr<OracleScheduler> Create(IOracle& oracle,
+                                                     IObservable& oracleObservable,
+                                                     IMessageEmitter& emitter,
+                                                     unsigned int maxHighPriority,
+                                                     unsigned int maxStandardPriority,
+                                                     unsigned int maxLowPriority);
+
+    ~OracleScheduler();
+
+    unsigned int GetMaxHighPriorityCommands() const
+    {
+      return maxHighPriorityCommands_;
+    }
+
+    unsigned int GetMaxStandardPriorityCommands() const
+    {
+      return maxStandardPriorityCommands_;
+    }
+
+    unsigned int GetMaxLowPriorityCommands() const
+    {
+      return maxLowPriorityCommands_;
+    }
+
+    uint64_t GetTotalScheduled() const
+    {
+      return totalScheduled_;
+    }
+
+    uint64_t GetTotalProcessed() const
+    {
+      return totalProcessed_;
+    }
+
+    // Cancel the HTTP requests that are still pending in the queues,
+    // and that are associated with the given receiver. Note that the
+    // receiver might still receive answers to HTTP requests that were
+    // already submitted to the oracle.
+    void CancelRequests(boost::shared_ptr<IObserver> receiver);
+
+    void CancelAllRequests();
+
+    void Schedule(boost::shared_ptr<IObserver> receiver,
+                  int priority,
+                  IOracleCommand* command /* Takes ownership */);
+  };
+}