/* ====== BEGIN INCLUDE FILE           mrds_finish_transaction.incl.pl1 =========================== */



/****^  HISTORY COMMENTS:
  1) change(85-11-17,Dupuis), approve(85-12-16,MCR7314),
     audit(86-02-04,Brunelle), install(86-02-05,MR12.0-1013):
     This entry is being made to cover the change made on 85-05-06 by Thanh
     Nguyen. The code now checks a local flag. (mrds error list #136).
                                                   END HISTORY COMMENTS */


/*
                    BEGIN_DESCRIPTION

   A generalized routine accessed by all MRDS modules that begin and commit 
   transactions.  The intent is that it be executed as inline code. It is 
   assumed that mrds_start_transaction was executed previously in the 
   procedure.  Prior to this include file the program should assign the value 
   of its local error code to mftxn_code.  The program utilizing this
   include file must supply a function labeled should_rollback that returns
   bit (1).  This routine should examine the error code mftxn_code and whether
   the transaction should be aborted or rolled back.  "0"b means abort and "1"b
   means rollback.  This procedure may choose to simply return "0"b as it 
   appears that MRDS will generally NOT rollback transactions.  This routine
   does rollback and restart if the before journal is full but only attempts it
   once.  A procedure labelled restore_significant_data must also be supplied, 
   where any data that was saved prior to the transaction is restored.  A 
   procedure consisting solely of a return statement can be supplied if 
   necessary.  After execution of this include file, mftxn_code must be
   examined.  If it was 0 before entering the code and is non-zero afterward,
   then the commit has failed.  Otherwise it will be unchanged.

                    END_DESCRIPTION

   Written 82-09-30 by Paul W. Benjamin.
   Modified 83-01-13 by PWB to add retry on deadlocks and to return a non-zero 
                     error code only when the transaction is in an error state.
   Modified 83-02-04 by PWB to reset transaction id to 0 upon completion.
   Modified 83-05-05 by PWB to abort when rollback fails, abandon when abort
		 fails, and to abort rather than rollback when bj is full.
   Modified 83-05-18 by PWB to use mftxn_temp_code in calls to abandon, abort
		 and rollback.
   Modified 83-05-19 by PWB to add mftxn_check_code label.  It is transferred
		 to by the mstxn_any_other procedure.
   Modified 85-04-14 by Thanh Nguyen not to commit the transaction in case of
                     the user already started his own transaction.
   Modified 85-05-06 by Thanh Nguyen to synchronize this include file between
                     the directory >ldd>include and >exl>mrd>i.
*/

dcl dm_error_$bj_journal_full fixed bin(35) ext static;
dcl dm_error_$lock_deadlock fixed bin(35) ext static;
dcl mftxn_code fixed bin (35);
dcl mftxn_temp_code fixed bin (35);
dcl transaction_manager_$commit_txn entry (bit (36) aligned, fixed bin (35));
dcl transaction_manager_$rollback_txn entry (bit (36) aligned, fixed bin (17), fixed bin (35));
	

	if mstxn_txn_id = "0"b | user_started_transaction = "1"b	/* No transaction or we did not started it */
	     then do;
	     mftxn_code = 0;
	     goto mftxn_exit;
	end;
mftxn_check_code:
	if mftxn_code = 0
	     then do;
	     call transaction_manager_$commit_txn (mstxn_txn_id, mftxn_code);
	     if mftxn_code ^= 0
		then do;
		call transaction_manager_$abort_txn (mstxn_txn_id, mftxn_temp_code);
		if mftxn_temp_code ^= 0
		     then call transaction_manager_$abandon_txn (mstxn_txn_id, mftxn_temp_code);
	     end;
	end;
	else do;
	     call restore_significant_data;
	     if mftxn_code = dm_error_$lock_deadlock	/* retry just once if deadlock */
		& mstxn_retries < 1		
		then do;
		     mstxn_retries = mstxn_retries + 1;
		     call transaction_manager_$rollback_txn (mstxn_txn_id, 0, mftxn_temp_code);
		     if mftxn_temp_code ^= 0
			then do;
			call transaction_manager_$abort_txn (mstxn_txn_id, mftxn_temp_code);
			if mftxn_temp_code ^= 0
			     then call transaction_manager_$abandon_txn (mstxn_txn_id, mftxn_temp_code);
		     end;
		     else do;
			mstxn_code = 0;
			goto mstxn_exit;		/* go back and try again */
		     end;
		end;
	     else if should_rollback ()		/* let the program decide */
		then do;
		call transaction_manager_$rollback_txn (mstxn_txn_id, 0, mftxn_temp_code);
		if mftxn_temp_code ^= 0
		     then do;
		     call transaction_manager_$abort_txn (mstxn_txn_id, mftxn_temp_code);
		     if mftxn_temp_code ^= 0
			then call transaction_manager_$abandon_txn (mstxn_txn_id, mftxn_temp_code);
		end;
		else do;
		     mstxn_code = 0;
		     goto mstxn_exit;		/* go back and try again */
		end;
	     end;
	     else do;
		call transaction_manager_$abort_txn (mstxn_txn_id, mftxn_temp_code);
		if mftxn_temp_code ^= 0
		     then call transaction_manager_$abandon_txn (mstxn_txn_id, mftxn_temp_code);
	     end;
	end;
	mstxn_txn_id = "0"b;			/* should never be nonzero unless there is a txn */
mftxn_exit:
     
/* ------ END INCLUDE FILE	          mrds_finish_transaction.incl.pl1 --------------------------- */


*/
                                          -----------------------------------------------------------


Historical Background

This edition of the Multics software materials and documentation is provided and donated
to Massachusetts Institute of Technology by Group Bull including Bull HN Information Systems Inc. 
as a contribution to computer science knowledge.  
This donation is made also to give evidence of the common contributions of Massachusetts Institute of Technology,
Bell Laboratories, General Electric, Honeywell Information Systems Inc., Honeywell Bull Inc., Groupe Bull
and Bull HN Information Systems Inc. to the development of this operating system. 
Multics development was initiated by Massachusetts Institute of Technology Project MAC (1963-1970),
renamed the MIT Laboratory for Computer Science and Artificial Intelligence in the mid 1970s, under the leadership
of Professor Fernando Jose Corbato. Users consider that Multics provided the best software architecture for 
managing computer hardware properly and for executing programs. Many subsequent operating systems 
incorporated Multics principles.
Multics was distributed in 1975 to 2000 by Group Bull in Europe , and in the U.S. by Bull HN Information Systems Inc., 
as successor in interest by change in name only to Honeywell Bull Inc. and Honeywell Information Systems Inc. .

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

Permission to use, copy, modify, and distribute these programs and their documentation for any purpose and without
fee is hereby granted,provided that the below copyright notice and historical background appear in all copies
and that both the copyright notice and historical background and this permission notice appear in supporting
documentation, and that the names of MIT, HIS, Bull or Bull HN not be used in advertising or publicity pertaining
to distribution of the programs without specific prior written permission.
    Copyright 1972 by Massachusetts Institute of Technology and Honeywell Information Systems Inc.
    Copyright 2006 by Bull HN Information Systems Inc.
    Copyright 2006 by Bull SAS
    All Rights Reserved

*/