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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT RUN-TIME COMPONENTS                         --

--                                                                          --

--                  G N A T . E X C E P T I O N _ T R A C E S               --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--                     Copyright (C) 2000-2009, AdaCore                     --

--                                                                          --

-- 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 2,  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.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNAT;  see file COPYING.  If not, write --

-- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --

-- Boston, MA 02110-1301, USA.                                              --

--                                                                          --

-- As a special exception,  if other files  instantiate  generics from this --

-- unit, or you link  this unit with other files  to produce an executable, --

-- this  unit  does not  by itself cause  the resulting  executable  to  be --

-- covered  by the  GNU  General  Public  License.  This exception does not --

-- however invalidate  any other reasons why  the executable file  might be --

-- covered by the  GNU Public License.                                      --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

with System.Standard_Library; use System.Standard_Library;

with System.Soft_Links;       use System.Soft_Links;

package body GNAT.Exception_Traces is

   --  Calling the decorator directly from where it is needed would require

   --  introducing nasty dependencies upon the spec of this package (typically

   --  in a-except.adb). We also have to deal with the fact that the traceback

   --  array within an exception occurrence and the one the decorator shall

   --  accept are of different types. These are two reasons for which a wrapper

   --  with a System.Address argument is indeed used to call the decorator

   --  provided by the user of this package. This wrapper is called via a

   --  soft-link, which either is null when no decorator is in place or "points

   --  to" the following function otherwise.

   function Decorator_Wrapper

     (Traceback : System.Address;

      Len       : Natural) return String;

   --  The wrapper to be called when a decorator is in place for exception

   --  backtraces.

   --

   --  Traceback is the address of the call chain array as stored in the

   --  exception occurrence and Len is the number of significant addresses

   --  contained in this array.

   Current_Decorator : Traceback_Decorator := null;

   --  The decorator to be called by the wrapper when it is not null, as set

   --  by Set_Trace_Decorator. When this access is null, the wrapper is null

   --  also and shall then not be called.

   -----------------------

   -- Decorator_Wrapper --

   -----------------------

   function Decorator_Wrapper

     (Traceback : System.Address;

      Len       : Natural) return String

   is

      Decorator_Traceback : Tracebacks_Array (1 .. Len);

      for Decorator_Traceback'Address use Traceback;

      --  Handle the "transition" from the array stored in the exception

      --  occurrence to the array expected by the decorator.

      pragma Import (Ada, Decorator_Traceback);

   begin

      return Current_Decorator.all (Decorator_Traceback);

   end Decorator_Wrapper;

   -------------------------

   -- Set_Trace_Decorator --

   -------------------------

   procedure Set_Trace_Decorator (Decorator : Traceback_Decorator) is

   begin

      Current_Decorator := Decorator;

      Traceback_Decorator_Wrapper :=

        (if Current_Decorator /= null

         then Decorator_Wrapper'Access else null);

   end Set_Trace_Decorator;

   ---------------

   -- Trace_Off --

   ---------------

   procedure Trace_Off is

   begin

      Exception_Trace := RM_Convention;

   end Trace_Off;

   --------------

   -- Trace_On --

   --------------

   procedure Trace_On (Kind : Trace_Kind) is

   begin

      case Kind is

         when Every_Raise =>

            Exception_Trace := Every_Raise;

         when Unhandled_Raise =>

            Exception_Trace := Unhandled_Raise;

      end case;

   end Trace_On;

end GNAT.Exception_Traces;