T826-026 Add a generic version of Has_Been_Canceled

to reduce copy/paste.

Author: reznikmm

source/server/lsp-generic_cancel_check.adb

@@ -0,0 +1,39 @@
+------------------------------------------------------------------------------
+--                         Language Server Protocol                         --
+--                                                                          --
+--                     Copyright (C) 2018-2021, AdaCore                     --
+--                                                                          --
+-- This 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.  This software is distributed in the hope  that it will be useful, --
+-- but WITHOUT ANY WARRANTY;  without even the implied warranty of MERCHAN- --
+-- TABILITY 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  this  software;   see  file --
+-- COPYING3.  If not, go to http://www.gnu.org/licenses for a complete copy --
+-- of the license.                                                          --
+------------------------------------------------------------------------------
+
+package body LSP.Generic_Cancel_Check is
+
+   Count : Natural := Max_Skip_Count;
+   --  Counter to restrict frequency of Request.Canceled checks
+
+   -----------------------
+   -- Has_Been_Canceled --
+   -----------------------
+
+   function Has_Been_Canceled return Boolean is
+   begin
+      Count := Count - 1;
+
+      if Count = 0 then
+         Count := Max_Skip_Count;
+         return Request.Canceled;
+      else
+         return False;
+      end if;
+   end Has_Been_Canceled;
+
+end LSP.Generic_Cancel_Check;

source/server/lsp-generic_cancel_check.ads

@@ -0,0 +1,36 @@
+------------------------------------------------------------------------------
+--                         Language Server Protocol                         --
+--                                                                          --
+--                     Copyright (C) 2018-2021, AdaCore                     --
+--                                                                          --
+-- This 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.  This software is distributed in the hope  that it will be useful, --
+-- but WITHOUT ANY WARRANTY;  without even the implied warranty of MERCHAN- --
+-- TABILITY 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  this  software;   see  file --
+-- COPYING3.  If not, go to http://www.gnu.org/licenses for a complete copy --
+-- of the license.                                                          --
+------------------------------------------------------------------------------
+--
+--  Each server request has an atomic flag to inform the handler that
+--  the request has been canceled. But, under a havy load, a frequent atomic
+--  checking cound generate overhead. This package provides a function to
+--  avoid an extra overhread by reducing atomic flag check frequency.
+
+with LSP.Messages.Server_Requests;
+
+generic
+   Request : in out LSP.Messages.Server_Requests.Server_Request'Class;
+   --  A request to check cancelation
+   Max_Skip_Count : Natural;
+   --  How much checks to skip before make a real atomic flag check
+
+package LSP.Generic_Cancel_Check is
+
+   function Has_Been_Canceled return Boolean
+     with Inline;
+
+end LSP.Generic_Cancel_Check;