10. Appendix B: Activity Access Callback Interface

10 Appendix B: Activity Access Callback Interface

10.1 mnesia_access Callback Behavior

-module(mnesia_frag).

%% Callback functions when accessed within an activity
-export([
	 lock/4,
	 write/5, delete/5, delete_object/5,
	 read/5, match_object/5, all_keys/4,
	 select/5,select/6,select_cont/3,
	 index_match_object/6, index_read/6,
	 foldl/6, foldr/6, table_info/4,
	 first/3, next/4, prev/4, last/3,
	 clear_table/4
       ]).

%% Callback functions which provides transparent
%% access of fragmented tables from any activity
%% access context.

lock(ActivityId, Opaque, {table , Tab}, LockKind) ->
    case frag_names(Tab) of
	[Tab] ->
	    mnesia:lock(ActivityId, Opaque, {table, Tab}, LockKind);	    
	Frags ->
	    DeepNs = [mnesia:lock(ActivityId, Opaque, {table, F}, LockKind) ||
			 F <- Frags],
	    mnesia_lib:uniq(lists:append(DeepNs))
    end;

lock(Activity
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