gnoga_2.1.2_5f127c56/deps/simple_components/os/windows/synchronization-interprocess-mutexes.adb

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
--                                                                    --
--  package                         Copyright (c)  Dmitry A. Kazakov  --
--     Synchronization.Interprocess.               Luebeck            --
--     Mutexes                                     Spring, 2018       --
--  Interface                                                         --
--                                Last revision :  01:09 01 May 2018  --
--                                                                    --
--  This  library  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 library  --
--  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 library; if not, write to  the  Free  Software  Foundation,  --
--  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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.       --
--____________________________________________________________________--

with Ada.Exceptions;     use Ada.Exceptions;
with Ada.IO_Exceptions;  use Ada.IO_Exceptions;

with System.Address_To_Access_Conversions;

package body Synchronization.Interprocess.Mutexes is

   procedure Check (Message : String; Code : DWORD := GetLastError) is
   begin
      if Code = ERROR_INVALID_HANDLE then
         Raise_Exception
         (  Status_Error'Identity,
            Message & "Mutex is not initialized or already finalized"
         );
      else
         Raise_From_LastError (Data_Error'Identity, Message, Code);
      end if;
   end Check;

   procedure Finalize (Object : in out Holder) is
   begin
      Release (Object.Resource.all);
   end Finalize;

   procedure Finalize (Object : in out Mutex) is
      Result : BOOL;
   begin
      if Object.External /= INVALID_HANDLE_VALUE then
         Result := CloseHandle (Object.External);
         Object.External := INVALID_HANDLE_VALUE;
      end if;
      Synchronization.Interprocess.Finalize
      (  Abstract_Shared_Object (Object)
      );
   end Finalize;

   function Get_Size (Object : Mutex) return Storage_Count is
   begin
      return Round (HANDLE'Max_Size_In_Storage_Elements);
   end Get_Size;

   function Get_Timeout (Object : Mutex) return Duration is
   begin
      return Duration (Long_Float (Object.Timeout) / 1000.0);
   end Get_Timeout;

   procedure Grab (Object : in out Mutex) is
   begin
      if Object.Owner = Current_Task then
         Object.Count := Object.Count + 1;
      else
         case WaitForSingleObject (Object.External, 0) is
            when WAIT_ABANDONED | WAIT_OBJECT_0 =>
               Object.Owner := Current_Task;
               Object.Count := 1;
            when WAIT_TIMEOUT =>
               return;
            when others =>
               Check ("Grab mutex fault: ");
         end case;
      end if;
   end Grab;

   procedure Initialize (Object : in out Holder) is
   begin
      Seize (Object.Resource.all);
   end Initialize;

   function Is_Mine (Object : Mutex) return Boolean is
   begin
      return Object.Owner = Current_Task;
   end Is_Mine;

   function Is_Owned (Object : Mutex) return Boolean is
      Result : BOOL;
   begin
      return Object.Owner /= Null_Task_Id;
   end Is_Owned;

   procedure Map
             (  Object   : in out Mutex;
                Shared   : in out Abstract_Shared_Environment'Class;
                Location : System.Address;
                Size     : Storage_Count;
                Owner    : Boolean
             )  is
      package Conversions is
         new System.Address_To_Access_Conversions (HANDLE);
      This : HANDLE renames Conversions.To_Pointer (Location).all;
   begin
      if Owner then
         Object.External := CreateMutex;
         if Object.External = 0 then
            Object.External := INVALID_HANDLE_VALUE;
            Raise_From_LastError
            (  Data_Error'Identity,
               "Mutex creation fault: ",
               GetLastError
            );
         end if;
         This := Object.External;
      else
         if (  0
            =  DuplicateHandle
               (  SourceProcessHandle => Shared.Server,
                  SourceHandle        => This,
                  TargetProcessHandle => GetCurrentProcess,
                  TargetHandle        =>
                     Object.External'Unchecked_Access
            )  )
         then
            Raise_From_LastError
            (  Data_Error'Identity,
               "Cannot duplicate a handle to the mutex: ",
               GetLastError
            );
         end if;
      end if;
   end Map;

   procedure Release (Object : in out Mutex) is
   begin
      if Object.Owner = Current_Task then
         Object.Count := Object.Count - 1;
         if Object.Count = 0 then
            Object.Owner := Null_Task_Id;
            if 0 = ReleaseMutex (Object.External) then
               Object.Owner := Null_Task_Id;
               declare
                  Code : constant DWORD := GetLastError;
               begin
                  Check ("Release mutex fault: ", Code);
               end;
            end if;
         end if;
      elsif Object.Owner = Null_Task_Id then
         Raise_Exception
         (  Ownership_Error'Identity,
            "Mutex is not owned"
         );
      else
         Raise_Exception
         (  Ownership_Error'Identity,
            "Mutex is owned by anothers task"
         );
      end if;
   end Release;

   procedure Seize (Object : in out Mutex) is
   begin
      if Object.Owner = Current_Task then
         Object.Count := Object.Count + 1;
      else
         case WaitForSingleObject (Object.External, Object.Timeout) is
            when WAIT_ABANDONED | WAIT_OBJECT_0 =>
               Object.Owner := Current_Task;
               Object.Count := 1;
            when WAIT_TIMEOUT =>
               Raise_Exception (Timeout_Error'Identity, "Timed out");
            when others =>
               Check ("Seize mutex fault: ");
         end case;
      end if;
   end Seize;

   procedure Seize (Object : in out Mutex; Timeout : Duration) is
   begin
      if Object.Owner = Current_Task then
         Object.Count := Object.Count + 1;
      else
         case WaitForSingleObject
              (  Object.External,
                 Milliseconds (Timeout)
              )  is
            when WAIT_ABANDONED | WAIT_OBJECT_0 =>
               Object.Owner := Current_Task;
               Object.Count := 1;
            when WAIT_TIMEOUT =>
               Raise_Exception (Timeout_Error'Identity, "Timed out");
            when others =>
               Check ("Seize mutex fault: ");
         end case;
      end if;
   end Seize;

   procedure Set_Timeout
             (  Object  : in out Mutex;
                Timeout : Duration
             )  is
   begin
      Object.Timeout := Milliseconds (Timeout);
   end Set_Timeout;

end Synchronization.Interprocess.Mutexes;