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------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                           S Y S T E M . R P C                            --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2009, Free Software Foundation, Inc.         --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------
 
--  Version for ???
 
with Unchecked_Deallocation;
with Ada.Streams;
 
with System.RPC.Net_Trace;
with System.RPC.Garlic;
with System.RPC.Streams;
pragma Elaborate (System.RPC.Garlic);
 
package body System.RPC is
 
   --  ??? general note: the debugging calls are very heavy, especially
   --  those that create exception handlers in every procedure. Do we
   --  really still need all this stuff?
 
   use type Ada.Streams.Stream_Element_Count;
   use type Ada.Streams.Stream_Element_Offset;
 
   use type Garlic.Protocol_Access;
   use type Garlic.Lock_Method;
 
   Max_Of_Message_Id : constant := 127;
 
   subtype Message_Id_Type is
     Integer range -Max_Of_Message_Id .. Max_Of_Message_Id;
   --  A message id is either a request id or reply id. A message id is
   --  provided with a message to a receiving stub which uses the opposite
   --  as a reply id. A message id helps to retrieve to which task is
   --  addressed a reply. When the environment task receives a message, the
   --  message id is extracted : a positive message id stands for a call, a
   --  negative message id stands for a reply. A null message id stands for
   --  an asynchronous request.
 
   subtype Request_Id_Type is Message_Id_Type range 1 .. Max_Of_Message_Id;
   --  When a message id is positive, it is a request
 
   type Message_Length_Per_Request is array (Request_Id_Type)
      of Ada.Streams.Stream_Element_Count;
 
   Header_Size : Ada.Streams.Stream_Element_Count :=
                   Streams.Get_Integer_Initial_Size +
                     Streams.Get_SEC_Initial_Size;
   --  Initial size needed for frequently used header streams
 
   Stream_Error : exception;
   --  Occurs when a read procedure is executed on an empty stream
   --  or when a write procedure is executed on a full stream
 
   Partition_RPC_Receiver : RPC_Receiver;
   --  Cache the RPC_Receiver passed by Establish_RPC_Receiver
 
   type Anonymous_Task_Node;
 
   type Anonymous_Task_Node_Access is access Anonymous_Task_Node;
   --  Types we need to construct a singly linked list of anonymous tasks
   --  This pool is maintained to avoid a task creation each time a RPC
   --  occurs - to be cont'd
 
   task type Anonymous_Task_Type (Self : Anonymous_Task_Node_Access) is
 
      entry Start
         (Message_Id   : Message_Id_Type;
          Partition    : Partition_ID;
          Params_Size  : Ada.Streams.Stream_Element_Count;
          Result_Size  : Ada.Streams.Stream_Element_Count;
          Protocol     : Garlic.Protocol_Access);
      --  This entry provides an anonymous task a remote call to perform.
      --  This task calls for a Request id is provided to construct the
      --  reply id by using -Request. Partition is used to send the reply
      --  message. Params_Size is the size of the calling stub Params stream.
      --  Then Protocol (used by the environment task previously) allows
      --  extraction of the message following the header (The header is
      --  extracted by the environment task)
      --  Note: grammar in above is obscure??? needs cleanup
 
   end Anonymous_Task_Type;
 
   type Anonymous_Task_Access is access Anonymous_Task_Type;
 
   type Anonymous_Task_List is record
      Head     : Anonymous_Task_Node_Access;
      Tail     : Anonymous_Task_Node_Access;
   end record;
 
   type Anonymous_Task_Node is record
      Element : Anonymous_Task_Access;
      Next    : Anonymous_Task_Node_Access;
   end record;
   --  Types we need to construct a singly linked list of anonymous tasks.
   --  This pool is maintained to avoid a task creation each time a RPC occurs.
 
   protected Garbage_Collector is
 
      procedure Allocate
         (Item : out Anonymous_Task_Node_Access);
      --  Anonymous task pool management : if there is an anonymous task
      --  left, use it. Otherwise, allocate a new one
 
      procedure Deallocate
         (Item : in out Anonymous_Task_Node_Access);
      --  Anonymous task pool management : queue this task in the pool
      --  of inactive anonymous tasks.
 
   private
 
      Anonymous_List : Anonymous_Task_Node_Access;
      --  The list root of inactive anonymous tasks
 
   end Garbage_Collector;
 
   task Dispatcher is
 
      entry New_Request (Request : out Request_Id_Type);
      --  To get a new request
 
      entry Wait_On (Request_Id_Type)
        (Length : out Ada.Streams.Stream_Element_Count);
      --  To block the calling stub when it waits for a reply
      --  When it is resumed, we provide the size of the reply
 
      entry Wake_Up
        (Request : Request_Id_Type;
         Length  : Ada.Streams.Stream_Element_Count);
      --  To wake up the calling stub when the environment task has
      --  received a reply for this request
 
   end Dispatcher;
 
   task Environnement is
 
      entry Start;
      --  Receive no message until Partition_Receiver is set
      --  Establish_RPC_Receiver decides when the environment task
      --  is allowed to start
 
   end Environnement;
 
   protected Partition_Receiver is
 
      entry Is_Set;
      --  Blocks if the Partition_RPC_Receiver has not been set
 
      procedure Set;
      --  Done by Establish_RPC_Receiver when Partition_RPC_Receiver
      --  is known
 
   private
 
      Was_Set : Boolean := False;
      --  True when Partition_RPC_Receiver has been set
 
   end Partition_Receiver;
   --  Anonymous tasks have to wait for the Partition_RPC_Receiver
   --  to be established
 
   type Debug_Level is
      (D_Elaborate,        --  About the elaboration of this package
       D_Communication,    --  About calls to Send and Receive
       D_Debug,            --  Verbose
       D_Exception);       --  Exception handler
   --  Debugging levels
 
   package Debugging is new System.RPC.Net_Trace (Debug_Level, "RPC : ");
   --  Debugging package
 
   procedure D
     (Flag : Debug_Level; Info : String) renames Debugging.Debug;
   --  Shortcut
 
   ------------------------
   -- Partition_Receiver --
   ------------------------
 
   protected body Partition_Receiver is
 
      -------------------------------
      -- Partition_Receiver.Is_Set --
      -------------------------------
 
      entry Is_Set when Was_Set is
      begin
         null;
      end Is_Set;
 
      ----------------------------
      -- Partition_Receiver.Set --
      ----------------------------
 
      procedure Set is
      begin
         Was_Set := True;
      end Set;
 
   end Partition_Receiver;
 
   ---------------
   -- Head_Node --
   ---------------
 
   procedure Head_Node
     (Index  : out Packet_Node_Access;
      Stream : Params_Stream_Type)
   is
   begin
      Index := Stream.Extra.Head;
 
   exception
      when others =>
         D (D_Exception, "exception in Head_Node");
         raise;
   end Head_Node;
 
   ---------------
   -- Tail_Node --
   ---------------
 
   procedure Tail_Node
     (Index  : out Packet_Node_Access;
      Stream : Params_Stream_Type)
   is
   begin
      Index := Stream.Extra.Tail;
 
   exception
      when others =>
         D (D_Exception, "exception in Tail_Node");
         raise;
   end Tail_Node;
 
   ---------------
   -- Null_Node --
   ---------------
 
   function Null_Node (Index : Packet_Node_Access) return Boolean is
   begin
      return Index = null;
 
   exception
      when others =>
         D (D_Exception, "exception in Null_Node");
         raise;
   end Null_Node;
 
   ----------------------
   -- Delete_Head_Node --
   ----------------------
 
   procedure Delete_Head_Node (Stream : in out Params_Stream_Type) is
 
      procedure Free is
        new Unchecked_Deallocation
        (Packet_Node, Packet_Node_Access);
 
      Next_Node : Packet_Node_Access := Stream.Extra.Head.Next;
 
   begin
      --  Delete head node and free memory usage
 
      Free (Stream.Extra.Head);
      Stream.Extra.Head := Next_Node;
 
      --  If the extra storage is empty, update tail as well
 
      if Stream.Extra.Head = null then
         Stream.Extra.Tail := null;
      end if;
 
   exception
      when others =>
         D (D_Exception, "exception in Delete_Head_Node");
         raise;
   end Delete_Head_Node;
 
   ---------------
   -- Next_Node --
   ---------------
 
   procedure Next_Node (Node : in out Packet_Node_Access) is
   begin
      --  Node is set to the next node
      --  If not possible, Stream_Error is raised
 
      if Node = null then
         raise Stream_Error;
      else
         Node := Node.Next;
      end if;
 
   exception
      when others =>
         D (D_Exception, "exception in Next_Node");
         raise;
   end Next_Node;
 
   ---------------------
   -- Append_New_Node --
   ---------------------
 
   procedure Append_New_Node (Stream : in out Params_Stream_Type) is
      Index : Packet_Node_Access;
 
   begin
      --  Set Index to the end of the linked list
 
      Tail_Node (Index, Stream);
 
      if Null_Node (Index) then
 
         --  The list is empty : set head as well
 
         Stream.Extra.Head := new Packet_Node;
         Stream.Extra.Tail := Stream.Extra.Head;
 
      else
         --  The list is not empty : link new node with tail
 
         Stream.Extra.Tail.Next := new Packet_Node;
         Stream.Extra.Tail := Stream.Extra.Tail.Next;
 
      end if;
 
   exception
      when others =>
         D (D_Exception, "exception in Append_New_Node");
         raise;
   end Append_New_Node;
 
   ----------
   -- Read --
   ----------
 
   procedure Read
     (Stream : in out Params_Stream_Type;
      Item   : out Ada.Streams.Stream_Element_Array;
      Last   : out Ada.Streams.Stream_Element_Offset)
     renames System.RPC.Streams.Read;
 
   -----------
   -- Write --
   -----------
 
   procedure Write
     (Stream : in out Params_Stream_Type;
      Item   : Ada.Streams.Stream_Element_Array)
     renames System.RPC.Streams.Write;
 
   -----------------------
   -- Garbage_Collector --
   -----------------------
 
   protected body Garbage_Collector is
 
      --------------------------------
      -- Garbage_Collector.Allocate --
      --------------------------------
 
      procedure Allocate (Item : out Anonymous_Task_Node_Access) is
         New_Anonymous_Task_Node : Anonymous_Task_Node_Access;
         Anonymous_Task          : Anonymous_Task_Access;
 
      begin
         --  If the list is empty, allocate a new anonymous task
         --  Otherwise, reuse the first queued anonymous task
 
         if Anonymous_List = null then
 
            --  Create a new anonymous task
            --  Provide this new task with its id to allow it
            --  to enqueue itself into the free anonymous task list
            --  with the function Deallocate
 
            New_Anonymous_Task_Node := new Anonymous_Task_Node;
            Anonymous_Task :=
             new Anonymous_Task_Type (New_Anonymous_Task_Node);
            New_Anonymous_Task_Node.all := (Anonymous_Task, null);
 
         else
            --  Extract one task from the list
            --  Set the Next field to null to avoid possible bugs
 
            New_Anonymous_Task_Node  := Anonymous_List;
            Anonymous_List := Anonymous_List.Next;
            New_Anonymous_Task_Node.Next := null;
 
         end if;
 
         --  Item is an out parameter
 
         Item := New_Anonymous_Task_Node;
 
      exception
         when others =>
            D (D_Exception, "exception in Allocate (Anonymous Task)");
            raise;
      end Allocate;
 
      ----------------------------------
      -- Garbage_Collector.Deallocate --
      ----------------------------------
 
      procedure Deallocate (Item : in out Anonymous_Task_Node_Access) is
      begin
         --  Enqueue the task in the free list
 
         Item.Next := Anonymous_List;
         Anonymous_List := Item;
 
      exception
         when others =>
            D (D_Exception, "exception in Deallocate (Anonymous Task)");
            raise;
      end Deallocate;
 
   end Garbage_Collector;
 
   ------------
   -- Do_RPC --
   ------------
 
   procedure Do_RPC
     (Partition  : Partition_ID;
      Params     : access Params_Stream_Type;
      Result     : access Params_Stream_Type)
   is
      Protocol   : Protocol_Access;
      Request    : Request_Id_Type;
      Header     : aliased Params_Stream_Type (Header_Size);
      R_Length   : Ada.Streams.Stream_Element_Count;
 
   begin
      --  Parameters order :
      --       Opcode   (provided and used by garlic)
      --   (1) Size     (provided by s-rpc and used by garlic)
      --                (size of (2)+(3)+(4)+(5))
      --   (2) Request  (provided by calling stub (resp receiving stub) and
      --                 used by anonymous task (resp Do_RPC))
      --                *** ZERO IF APC ***
      --   (3) Res.len. (provided by calling stubs and used by anonymous task)
      --                *** ZERO IF APC ***
      --   (4) Receiver (provided by calling stubs and used by anonymous task)
      --   (5) Params   (provided by calling stubs and used by anonymous task)
 
      --  The call is a remote call or a local call. A local call occurs
      --  when the pragma All_Calls_Remote has been specified. Do_RPC is
      --  called and the execution has to be performed in the PCS
 
      if Partition /= Garlic.Get_My_Partition_ID then
 
         --  Get a request id to be resumed when the reply arrives
 
         Dispatcher.New_Request (Request);
 
         --  Build header = request (2) + result.initial_size (3)
 
         D (D_Debug, "Do_RPC - Build header");
         Streams.Allocate (Header);
         Streams.Integer_Write_Attribute            --  (2)
           (Header'Access, Request);
         System.RPC.Streams.SEC_Write_Attribute     --  (3)
           (Header'Access, Result.Initial_Size);
 
         --  Get a protocol method to communicate with the remote partition
         --  and give the message size
 
         D (D_Communication,
            "Do_RPC - Lookup for protocol to talk to partition" &
            Partition_ID'Image (Partition));
         Garlic.Initiate_Send
           (Partition,
            Streams.Get_Stream_Size (Header'Access) +
            Streams.Get_Stream_Size (Params), --  (1)
            Protocol,
            Garlic.Remote_Call);
 
         --  Send the header by using the protocol method
 
         D (D_Communication, "Do_RPC - Send Header to partition" &
            Partition_ID'Image (Partition));
         Garlic.Send
           (Protocol.all,
            Partition,
            Header'Access);                         --  (2) + (3)
 
         --  The header is deallocated
 
         Streams.Deallocate (Header);
 
         --  Send Params from Do_RPC
 
         D (D_Communication, "Do_RPC - Send Params to partition" &
            Partition_ID'Image (Partition));
         Garlic.Send
           (Protocol.all,
            Partition,
            Params);                                --  (4) + (5)
 
         --  Let Garlic know we have nothing else to send
 
         Garlic.Complete_Send
           (Protocol.all,
            Partition);
         D (D_Debug, "Do_RPC - Suspend");
 
         --  Wait for a reply and get the reply message length
 
         Dispatcher.Wait_On (Request) (R_Length);
         D (D_Debug, "Do_RPC - Resume");
 
         declare
            New_Result : aliased Params_Stream_Type (R_Length);
         begin
            --  Adjust the Result stream size right now to be able to load
            --  the stream in one receive call. Create a temporary result
            --  that will be substituted to Do_RPC one
 
            Streams.Allocate (New_Result);
 
            --  Receive the reply message from receiving stub
 
            D (D_Communication, "Do_RPC - Receive Result from partition" &
            Partition_ID'Image (Partition));
            Garlic.Receive
              (Protocol.all,
               Partition,
               New_Result'Access);
 
            --  Let Garlic know we have nothing else to receive
 
            Garlic.Complete_Receive
              (Protocol.all,
               Partition);
 
            --  Update calling stub Result stream
 
            D (D_Debug, "Do_RPC - Reconstruct Result");
            Streams.Deallocate (Result.all);
            Result.Initial := New_Result.Initial;
            Streams.Dump ("|||", Result.all);
 
         end;
 
      else
         --  Do RPC locally and first wait for Partition_RPC_Receiver to be
         --  set
 
         Partition_Receiver.Is_Set;
         D (D_Debug, "Do_RPC - Locally");
         Partition_RPC_Receiver.all (Params, Result);
 
      end if;
 
   exception
      when others =>
         D (D_Exception, "exception in Do_RPC");
         raise;
   end Do_RPC;
 
   ------------
   -- Do_APC --
   ------------
 
   procedure Do_APC
     (Partition  : Partition_ID;
      Params     : access Params_Stream_Type)
   is
      Message_Id : Message_Id_Type := 0;
      Protocol   : Protocol_Access;
      Header     : aliased Params_Stream_Type (Header_Size);
 
   begin
      --  For more informations, see above
      --  Request = 0 as we are not waiting for a reply message
      --  Result length = 0 as we don't expect a result at all
 
      if Partition /= Garlic.Get_My_Partition_ID then
 
         --  Build header = request (2) + result.initial_size (3)
         --  As we have an APC, the request id is null to indicate
         --  to the receiving stub that we do not expect a reply
         --  This comes from 0 = -0
 
         D (D_Debug, "Do_APC - Build Header");
         Streams.Allocate (Header);
         Streams.Integer_Write_Attribute
           (Header'Access, Integer (Message_Id));
         Streams.SEC_Write_Attribute
           (Header'Access, 0);
 
         --  Get a protocol method to communicate with the remote partition
         --  and give the message size
 
         D (D_Communication,
            "Do_APC - Lookup for protocol to talk to partition" &
            Partition_ID'Image (Partition));
         Garlic.Initiate_Send
           (Partition,
            Streams.Get_Stream_Size (Header'Access) +
            Streams.Get_Stream_Size (Params),
            Protocol,
            Garlic.Remote_Call);
 
         --  Send the header by using the protocol method
 
         D (D_Communication, "Do_APC - Send Header to partition" &
            Partition_ID'Image (Partition));
         Garlic.Send
           (Protocol.all,
            Partition,
            Header'Access);
 
         --  The header is deallocated
 
         Streams.Deallocate (Header);
 
         --  Send Params from Do_APC
 
         D (D_Communication, "Do_APC - Send Params to partition" &
            Partition_ID'Image (Partition));
         Garlic.Send
           (Protocol.all,
            Partition,
            Params);
 
         --  Let Garlic know we have nothing else to send
 
         Garlic.Complete_Send
           (Protocol.all,
            Partition);
      else
 
         declare
            Result   : aliased Params_Stream_Type (0);
         begin
            --  Result is here a dummy parameter
            --  No reason to deallocate as it is not allocated at all
 
            Partition_Receiver.Is_Set;
            D (D_Debug, "Do_APC - Locally");
            Partition_RPC_Receiver.all (Params, Result'Access);
 
         end;
 
      end if;
 
   exception
      when others =>
         D (D_Exception, "exception in Do_APC");
         raise;
   end Do_APC;
 
   ----------------------------
   -- Establish_RPC_Receiver --
   ----------------------------
 
   procedure Establish_RPC_Receiver
     (Partition : Partition_ID;
      Receiver  : RPC_Receiver)
   is
   begin
      --  Set Partition_RPC_Receiver and allow RPC mechanism
 
      Partition_RPC_Receiver := Receiver;
      Partition_Receiver.Set;
      D (D_Elaborate, "Partition_Receiver is set");
 
   exception
      when others =>
         D (D_Exception, "exception in Establish_RPC_Receiver");
         raise;
   end Establish_RPC_Receiver;
 
   ----------------
   -- Dispatcher --
   ----------------
 
   task body Dispatcher is
      Last_Request : Request_Id_Type := Request_Id_Type'First;
      Current_Rqst : Request_Id_Type := Request_Id_Type'First;
      Current_Size : Ada.Streams.Stream_Element_Count;
 
   begin
      loop
         --  Three services:
 
         --    New_Request to get an entry in Dispatcher table
 
         --    Wait_On for Do_RPC calls
 
         --    Wake_Up called by environment task when a Do_RPC receives
         --    the result of its remote call
 
         select
            accept New_Request (Request : out Request_Id_Type) do
               Request := Last_Request;
 
               --  << TODO >>
               --  ??? Availability check
 
               if Last_Request = Request_Id_Type'Last then
                  Last_Request := Request_Id_Type'First;
               else
                  Last_Request := Last_Request + 1;
               end if;
 
            end New_Request;
 
         or
            accept Wake_Up
              (Request : Request_Id_Type;
               Length  : Ada.Streams.Stream_Element_Count)
            do
               --  The environment reads the header and has been notified
               --  of the reply id and the size of the result message
 
               Current_Rqst := Request;
               Current_Size := Length;
 
            end Wake_Up;
 
            --  << TODO >>
            --  ??? Must be select with delay for aborted tasks
 
            select
 
               accept Wait_On (Current_Rqst)
                 (Length  : out Ada.Streams.Stream_Element_Count)
               do
                  Length := Current_Size;
               end Wait_On;
 
            or
               --  To free the Dispatcher when a task is aborted
 
               delay 1.0;
 
            end select;
 
         or
            terminate;
         end select;
 
      end loop;
 
   exception
      when others =>
         D (D_Exception, "exception in Dispatcher body");
         raise;
   end Dispatcher;
 
   -------------------------
   -- Anonymous_Task_Type --
   -------------------------
 
   task body Anonymous_Task_Type is
      Whoami       : Anonymous_Task_Node_Access := Self;
      C_Message_Id : Message_Id_Type;                  --  Current Message Id
      C_Partition  : Partition_ID;                     --  Current Partition
      Params_S     : Ada.Streams.Stream_Element_Count; --  Params message size
      Result_S     : Ada.Streams.Stream_Element_Count; --  Result message size
      C_Protocol   : Protocol_Access;                  --  Current Protocol
 
   begin
      loop
         --  Get a new RPC to execute
 
         select
            accept Start
              (Message_Id   : Message_Id_Type;
               Partition    : Partition_ID;
               Params_Size  : Ada.Streams.Stream_Element_Count;
               Result_Size  : Ada.Streams.Stream_Element_Count;
               Protocol     : Protocol_Access)
            do
               C_Message_Id := Message_Id;
               C_Partition  := Partition;
               Params_S     := Params_Size;
               Result_S     := Result_Size;
               C_Protocol   := Protocol;
            end Start;
         or
            terminate;
         end select;
 
         declare
            Params : aliased Params_Stream_Type (Params_S);
            Result : aliased Params_Stream_Type (Result_S);
            Header : aliased Params_Stream_Type (Header_Size);
 
         begin
            --  We reconstruct all the client context : Params and Result
            --  with the SAME size, then we receive Params from calling stub
 
            D (D_Communication,
               "Anonymous Task - Receive Params from partition" &
               Partition_ID'Image (C_Partition));
            Garlic.Receive
               (C_Protocol.all,
                C_Partition,
                Params'Access);
 
            --  Let Garlic know we don't receive anymore
 
            Garlic.Complete_Receive
               (C_Protocol.all,
                C_Partition);
 
            --  Check that Partition_RPC_Receiver has been set
 
            Partition_Receiver.Is_Set;
 
            --  Do it locally
 
            D (D_Debug,
               "Anonymous Task - Perform Partition_RPC_Receiver for request" &
               Message_Id_Type'Image (C_Message_Id));
            Partition_RPC_Receiver (Params'Access, Result'Access);
 
            --  If this was a RPC we send the result back
            --  Otherwise, do nothing else than deallocation
 
            if C_Message_Id /= 0 then
 
               --  Build Header = -C_Message_Id + Result Size
               --  Provide the request id to the env task of the calling
               --  stub partition We get the real result stream size : the
               --  calling stub (in Do_RPC) updates its size to this one
 
               D (D_Debug, "Anonymous Task - Build Header");
               Streams.Allocate (Header);
               Streams.Integer_Write_Attribute
                 (Header'Access, Integer (-C_Message_Id));
               Streams.SEC_Write_Attribute
                 (Header'Access,
                  Streams.Get_Stream_Size (Result'Access));
 
               --  Get a protocol method to communicate with the remote
               --  partition and give the message size
 
               D (D_Communication,
                  "Anonymous Task - Lookup for protocol talk to partition" &
                  Partition_ID'Image (C_Partition));
               Garlic.Initiate_Send
                 (C_Partition,
                  Streams.Get_Stream_Size (Header'Access) +
                  Streams.Get_Stream_Size (Result'Access),
                  C_Protocol,
                  Garlic.Remote_Call);
 
               --  Send the header by using the protocol method
 
               D (D_Communication,
                  "Anonymous Task - Send Header to partition" &
                  Partition_ID'Image (C_Partition));
               Garlic.Send
                 (C_Protocol.all,
                  C_Partition,
                  Header'Access);
 
               --  Send Result toDo_RPC
 
               D (D_Communication,
                  "Anonymous Task - Send Result to partition" &
                  Partition_ID'Image (C_Partition));
               Garlic.Send
                 (C_Protocol.all,
                  C_Partition,
                  Result'Access);
 
               --  Let Garlic know we don't send anymore
 
               Garlic.Complete_Send
                 (C_Protocol.all,
                  C_Partition);
               Streams.Deallocate (Header);
            end if;
 
            Streams.Deallocate (Params);
            Streams.Deallocate (Result);
         end;
 
         --  Enqueue into the anonymous task free list : become inactive
 
         Garbage_Collector.Deallocate (Whoami);
 
      end loop;
 
   exception
      when others =>
         D (D_Exception, "exception in Anonymous_Task_Type body");
         raise;
   end Anonymous_Task_Type;
 
   -----------------
   -- Environment --
   -----------------
 
   task body Environnement is
      Partition    : Partition_ID;
      Message_Size : Ada.Streams.Stream_Element_Count;
      Result_Size  : Ada.Streams.Stream_Element_Count;
      Message_Id   : Message_Id_Type;
      Header       : aliased Params_Stream_Type (Header_Size);
      Protocol     : Protocol_Access;
      Anonymous    : Anonymous_Task_Node_Access;
 
   begin
      --  Wait the Partition_RPC_Receiver to be set
 
      accept Start;
      D (D_Elaborate, "Environment task elaborated");
 
      loop
         --  We receive first a fixed size message : the header
         --  Header = Message Id + Message Size
 
         Streams.Allocate (Header);
 
         --  Garlic provides the size of the received message and the
         --  protocol to use to communicate with the calling partition
 
         Garlic.Initiate_Receive
           (Partition,
            Message_Size,
            Protocol,
            Garlic.Remote_Call);
         D (D_Communication,
            "Environment task - Receive protocol to talk to active partition" &
            Partition_ID'Image (Partition));
 
         --  Extract the header to route the message either to
         --  an anonymous task (Message Id > 0 <=> Request Id)
         --  or to a waiting task (Message Id < 0 <=> Reply Id)
 
         D (D_Communication,
            "Environment task - Receive Header from partition" &
            Partition_ID'Image (Partition));
         Garlic.Receive
           (Protocol.all,
            Partition,
            Header'Access);
 
         --  Evaluate the remaining size of the message
 
         Message_Size := Message_Size -
            Streams.Get_Stream_Size (Header'Access);
 
         --  Extract from header : message id and message size
 
         Streams.Integer_Read_Attribute (Header'Access, Message_Id);
         Streams.SEC_Read_Attribute (Header'Access, Result_Size);
 
         if Streams.Get_Stream_Size (Header'Access) /= 0 then
 
            --  If there are stream elements left in the header ???
 
            D (D_Exception, "Header is not empty");
            raise Program_Error;
 
         end if;
 
         if Message_Id < 0 then
 
            --  The message was sent by a receiving stub : wake up the
            --  calling task - We have a reply there
 
            D (D_Debug, "Environment Task - Receive Reply from partition" &
               Partition_ID'Image (Partition));
            Dispatcher.Wake_Up (-Message_Id, Result_Size);
 
         else
            --  The message was send by a calling stub : get an anonymous
            --  task to perform the job
 
            D (D_Debug, "Environment Task - Receive Request from partition" &
               Partition_ID'Image (Partition));
            Garbage_Collector.Allocate (Anonymous);
 
            --  We subtracted the size of the header from the size of the
            --  global message in order to provide immediately Params size
 
            Anonymous.Element.Start
              (Message_Id,
               Partition,
               Message_Size,
               Result_Size,
               Protocol);
 
         end if;
 
         --  Deallocate header : unnecessary - WARNING
 
         Streams.Deallocate (Header);
 
      end loop;
 
   exception
      when others =>
         D (D_Exception, "exception in Environment");
         raise;
   end Environnement;
 
begin
   --  Set debugging information
 
   Debugging.Set_Environment_Variable ("RPC");
   Debugging.Set_Debugging_Name ("D", D_Debug);
   Debugging.Set_Debugging_Name ("E", D_Exception);
   Debugging.Set_Debugging_Name ("C", D_Communication);
   Debugging.Set_Debugging_Name ("Z", D_Elaborate);
   D (D_Elaborate, "To be elaborated");
 
   --  When this body is elaborated we should ensure that RCI name server
   --  has been already elaborated : this means that Establish_RPC_Receiver
   --  has already been called and that Partition_RPC_Receiver is set
 
   Environnement.Start;
   D (D_Elaborate, "ELABORATED");
 
end System.RPC;