gcc/ada/a-caldel.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --                   A D A . C A L E N D A R . D E L A Y S                  --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --             Copyright (C) 1991-1994, Florida State University            --
  10 --                     Copyright (C) 1995-2005, AdaCore                     --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  21 -- Boston, MA 02110-1301, USA.                                              --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University.       --
  31 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 with System.OS_Primitives;
  36 --  Used for Delay_Modes
  37 --           Max_Sensible_Delay
  38
  39 with System.Soft_Links;
  40 --  Used for Timed_Delay
  41
  42 with System.Traces;
  43 --  Used for Send_Trace_Info
  44
  45 with System.Parameters;
  46 --  used for Runtime_Traces
  47
  48 package body Ada.Calendar.Delays is
  49
  50    package OSP renames System.OS_Primitives;
  51    package SSL renames System.Soft_Links;
  52
  53    use type SSL.Timed_Delay_Call;
  54
  55    use System.Traces;
  56
  57    --  Earlier, the following operations were implemented using
  58    --  System.Time_Operations.  The idea was to avoid sucking in the tasking
  59    --  packages.  This did not work.  Logically, we can't have it both ways.
  60    --  There is no way to implement time delays that will have correct task
  61    --  semantics without reference to the tasking run-time system.
  62    --  To achieve this goal, we now use soft links.
  63
  64    -----------------------
  65    -- Local Subprograms --
  66    -----------------------
  67
  68    procedure Timed_Delay_NT (Time : Duration; Mode : Integer);
  69    --  Timed delay procedure used when no tasking is active
  70
  71    ---------------
  72    -- Delay_For --
  73    ---------------
  74
  75    procedure Delay_For (D : Duration) is
  76    begin
  77       if System.Parameters.Runtime_Traces then
  78          Send_Trace_Info (W_Delay, D);
  79       end if;
  80
  81       SSL.Timed_Delay.all (Duration'Min (D, OSP.Max_Sensible_Delay),
  82                            OSP.Relative);
  83
  84       if System.Parameters.Runtime_Traces then
  85          Send_Trace_Info (M_Delay, D);
  86       end if;
  87    end Delay_For;
  88
  89    -----------------
  90    -- Delay_Until --
  91    -----------------
  92
  93    procedure Delay_Until (T : Time) is
  94       D : constant Duration := To_Duration (T);
  95
  96    begin
  97       if System.Parameters.Runtime_Traces then
  98          Send_Trace_Info (WU_Delay, D);
  99       end if;
 100
 101       SSL.Timed_Delay.all (D, OSP.Absolute_Calendar);
 102
 103       if System.Parameters.Runtime_Traces then
 104          Send_Trace_Info (M_Delay, D);
 105       end if;
 106    end Delay_Until;
 107
 108    --------------------
 109    -- Timed_Delay_NT --
 110    --------------------
 111
 112    procedure Timed_Delay_NT (Time : Duration; Mode : Integer) is
 113    begin
 114       OSP.Timed_Delay (Time, Mode);
 115    end Timed_Delay_NT;
 116
 117    -----------------
 118    -- To_Duration --
 119    -----------------
 120
 121    function To_Duration (T : Time) return Duration is
 122    begin
 123       return Duration (T);
 124    end To_Duration;
 125
 126 begin
 127    --  Set up the Timed_Delay soft link to the non tasking version
 128    --  if it has not been already set.
 129
 130    --  If tasking is present, Timed_Delay has already set this soft
 131    --  link, or this will be overriden during the elaboration of
 132    --  System.Tasking.Initialization
 133
 134    if SSL.Timed_Delay = null then
 135       SSL.Timed_Delay := Timed_Delay_NT'Access;
 136    end if;
 137 end Ada.Calendar.Delays;