mnesia_lib.erl

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	    Time	    
    end.

report_system_event(Event0) ->
    Event = {mnesia_system_event, Event0},
    report_system_event(catch_notify(Event), Event),
    case ?catch_val(subscribers) of
	{'EXIT', _} -> ignore;
	Pids -> lists:foreach(fun(Pid) -> Pid ! Event end, Pids)
    end,
    ok.

catch_notify(Event) ->
    case whereis(mnesia_event) of
	undefined ->
	    {'EXIT', {badarg, {mnesia_event, Event}}};
	Pid ->
	    gen_event:notify(Pid, Event)
    end.

report_system_event({'EXIT', Reason}, Event) ->
    Mod = mnesia_monitor:get_env(event_module),
    case mnesia_sup:start_event() of
	{ok, Pid} ->
	    link(Pid),
	    gen_event:call(mnesia_event, Mod, Event, infinity),
	    unlink(Pid),

            %% We get an exit signal if server dies
            receive
                {'EXIT', Pid, _Reason} ->
                    {error, {node_not_running, node()}}
            after 0 ->
		    gen_event:stop(mnesia_event),
                    ok
            end;

	Error ->
	    Msg = "Mnesia(~p): Cannot report event ~p: ~p (~p)~n",
	    error_logger:format(Msg, [node(), Event, Reason, Error])
    end;
report_system_event(_Res, _Event) ->
    ignore.

%% important messages are reported regardless of debug level
important(Format, Args) ->
    save({Format, Args}),
    report_system_event({mnesia_info, Format, Args}).

%% Warning messages are reported regardless of debug level
warning(Format, Args) ->
    save({Format, Args}),
    report_system_event({mnesia_warning, Format, Args}).

%% error messages are reported regardless of debug level
error(Format, Args) ->
    save({Format, Args}),
    report_system_event({mnesia_error, Format, Args}).

%% verbose messages are reported if debug level == debug or verbose
verbose(Format, Args) ->
    case mnesia_monitor:get_env(debug) of
	none ->    save({Format, Args});
	verbose -> important(Format, Args);
	debug ->   important(Format, Args);
	trace ->   important(Format, Args)
    end.

%% debug message are display if debug level == 2
dbg_out(Format, Args) ->
    case mnesia_monitor:get_env(debug) of
	none ->    ignore;
	verbose -> save({Format, Args});
	_ ->  report_system_event({mnesia_info, Format, Args})
    end.

%% Keep the last 10 debug print outs
save(DbgInfo) ->
    catch save2(DbgInfo).

save2(DbgInfo) ->
    Key = {'$$$_report', current_pos},
    P =
	case ?ets_lookup_element(mnesia_gvar, Key, 2) of
	    30 -> -1;
	    I -> I
	end,
    set({'$$$_report', current_pos}, P+1),
    set({'$$$_report', P+1}, {date(), time(), DbgInfo}).

copy_file(From, To) ->
    case file:rawopen(From, {binary, read}) of
	{ok, F} ->
	    case file:rawopen(To, {binary, write}) of
		{ok, T} ->
		    Res = copy_file_loop(F, T, 8000),
		    file:close(F),
		    file:close(T),
		    Res;
		{error, Reason} ->
		    {error, Reason}
	    end;
	{error, Reason} ->
	    {error, Reason}
    end.

copy_file_loop(F, T, ChunkSize) ->
    case file:read(F, ChunkSize) of
	{ok, {0, _}} ->
	    ok;
	{ok, {_, Bin}} ->
	    file:write(T, Bin),
	    copy_file_loop(F, T, ChunkSize);
	{ok, Bin} ->
	    file:write(T, Bin),
	    copy_file_loop(F, T, ChunkSize);
	eof ->
	    ok;
	{error, Reason} ->
	    {error, Reason}
    end.


%%%%%%%%%%%%
%% versions of all the lowlevel db funcs that determine whether we
%% shall go to disc or ram to do the actual operation.

db_get(Tab, Key) ->
    db_get(val({Tab, storage_type}), Tab, Key).
db_get(ram_copies, Tab, Key) -> ?ets_lookup(Tab, Key);
db_get(disc_copies, Tab, Key) -> ?ets_lookup(Tab, Key);
db_get(disc_only_copies, Tab, Key) -> dets:lookup(Tab, Key).

db_init_chunk(Tab) ->
    db_init_chunk(val({Tab, storage_type}), Tab, 1000).
db_init_chunk(Tab, N) ->
    db_init_chunk(val({Tab, storage_type}), Tab, N).

db_init_chunk(disc_only_copies, Tab, N) ->
    dets:select(Tab, [{'_', [], ['$_']}], N);
db_init_chunk(_, Tab, N) ->
    ets:select(Tab, [{'_', [], ['$_']}], N).

db_chunk(disc_only_copies, State) ->
    dets:select(State);
db_chunk(_, State) ->
    ets:select(State).

db_put(Tab, Val) ->
    db_put(val({Tab, storage_type}), Tab, Val).

db_put(ram_copies, Tab, Val) -> ?ets_insert(Tab, Val), ok;
db_put(disc_copies, Tab, Val) -> ?ets_insert(Tab, Val), ok;
db_put(disc_only_copies, Tab, Val) -> dets:insert(Tab, Val).

db_match_object(Tab, Pat) ->
    db_match_object(val({Tab, storage_type}), Tab, Pat).
db_match_object(Storage, Tab, Pat) ->
    db_fixtable(Storage, Tab, true),
    Res = catch_match_object(Storage, Tab, Pat),
    db_fixtable(Storage, Tab, false),
    case Res of
	{'EXIT', Reason} -> exit(Reason);
	_ -> Res
    end.

catch_match_object(disc_only_copies, Tab, Pat) ->
    catch dets:match_object(Tab, Pat);
catch_match_object(_, Tab, Pat) ->
    catch ets:match_object(Tab, Pat).

db_select(Tab, Pat) ->
    db_select(val({Tab, storage_type}), Tab, Pat).

db_select(Storage, Tab, Pat) ->
    db_fixtable(Storage, Tab, true),
    Res = catch_select(Storage, Tab, Pat),
    db_fixtable(Storage, Tab, false),
    case Res of
	{'EXIT', Reason} -> exit(Reason);
	_ -> Res
    end.

catch_select(disc_only_copies, Tab, Pat) ->
    catch dets:select(Tab, Pat);
catch_select(_, Tab, Pat) ->
    catch ets:select(Tab, Pat).

db_select_init(disc_only_copies, Tab, Pat, Limit) ->
    dets:select(Tab, Pat, Limit);
db_select_init(_, Tab, Pat, Limit) ->
    ets:select(Tab, Pat, Limit).

db_select_cont(disc_only_copies, Cont0, Ms) ->
    Cont = dets:repair_continuation(Cont0, Ms),
    dets:select(Cont);
db_select_cont(_, Cont0, Ms) ->
    Cont = ets:repair_continuation(Cont0, Ms),
    ets:select(Cont).

db_fixtable(ets, Tab, Bool) ->
    ets:safe_fixtable(Tab, Bool);
db_fixtable(ram_copies, Tab, Bool) ->
    ets:safe_fixtable(Tab, Bool);
db_fixtable(disc_copies, Tab, Bool) ->
    ets:safe_fixtable(Tab, Bool);
db_fixtable(dets, Tab, Bool) ->
    dets:safe_fixtable(Tab, Bool);
db_fixtable(disc_only_copies, Tab, Bool) ->
    dets:safe_fixtable(Tab, Bool).

db_erase(Tab, Key) ->
    db_erase(val({Tab, storage_type}), Tab, Key).
db_erase(ram_copies, Tab, Key) -> ?ets_delete(Tab, Key), ok;
db_erase(disc_copies, Tab, Key) -> ?ets_delete(Tab, Key), ok;
db_erase(disc_only_copies, Tab, Key) -> dets:delete(Tab, Key).

db_match_erase(Tab, Pat) ->
    db_match_erase(val({Tab, storage_type}), Tab, Pat).
db_match_erase(ram_copies, Tab, Pat) -> ?ets_match_delete(Tab, Pat), ok;
db_match_erase(disc_copies, Tab, Pat) -> ?ets_match_delete(Tab, Pat), ok;
db_match_erase(disc_only_copies, Tab, Pat) -> dets:match_delete(Tab, Pat).

db_first(Tab) ->
    db_first(val({Tab, storage_type}), Tab).
db_first(ram_copies, Tab) -> ?ets_first(Tab);
db_first(disc_copies, Tab) -> ?ets_first(Tab);
db_first(disc_only_copies, Tab) -> dets:first(Tab).

db_next_key(Tab, Key) ->
    db_next_key(val({Tab, storage_type}), Tab, Key).
db_next_key(ram_copies, Tab, Key) -> ?ets_next(Tab, Key);
db_next_key(disc_copies, Tab, Key) -> ?ets_next(Tab, Key);
db_next_key(disc_only_copies, Tab, Key) -> dets:next(Tab, Key).

db_last(Tab) ->
    db_last(val({Tab, storage_type}), Tab).
db_last(ram_copies, Tab) -> ?ets_last(Tab);
db_last(disc_copies, Tab) -> ?ets_last(Tab);
db_last(disc_only_copies, Tab) -> dets:first(Tab). %% Dets don't have order

db_prev_key(Tab, Key) ->
    db_prev_key(val({Tab, storage_type}), Tab, Key).
db_prev_key(ram_copies, Tab, Key) -> ?ets_prev(Tab, Key);
db_prev_key(disc_copies, Tab, Key) -> ?ets_prev(Tab, Key);
db_prev_key(disc_only_copies, Tab, Key) -> dets:next(Tab, Key). %% Dets don't have order

db_slot(Tab, Pos) ->
    db_slot(val({Tab, storage_type}), Tab, Pos).
db_slot(ram_copies, Tab, Pos) -> ?ets_slot(Tab, Pos);
db_slot(disc_copies, Tab, Pos) -> ?ets_slot(Tab, Pos);
db_slot(disc_only_copies, Tab, Pos) -> dets:slot(Tab, Pos).

db_update_counter(Tab, C, Val) ->
    db_update_counter(val({Tab, storage_type}), Tab, C, Val).
db_update_counter(ram_copies, Tab, C, Val) ->
    ?ets_update_counter(Tab, C, Val);
db_update_counter(disc_copies, Tab, C, Val) ->
    ?ets_update_counter(Tab, C, Val);
db_update_counter(disc_only_copies, Tab, C, Val) ->
    dets:update_counter(Tab, C, Val).

db_erase_tab(Tab) ->
    db_erase_tab(val({Tab, storage_type}), Tab).
db_erase_tab(ram_copies, Tab) -> ?ets_delete_table(Tab);
db_erase_tab(disc_copies, Tab) -> ?ets_delete_table(Tab);
db_erase_tab(disc_only_copies, _Tab) -> ignore.

%% assuming that Tab is a valid ets-table
dets_to_ets(Tabname, Tab, File, Type, Rep, Lock) ->
    {Open, Close} = mkfuns(Lock),
    case Open(Tabname, [{file, File}, {type, disk_type(Tab, Type)},
			{keypos, 2}, {repair, Rep}]) of
	{ok, Tabname} ->
	    Res = dets:to_ets(Tabname, Tab),
	    Close(Tabname),
	    trav_ret(Res, Tab);
	Other ->
	    Other
    end.

trav_ret(Tabname, Tabname) -> loaded;
trav_ret(Other, _Tabname) -> Other.

mkfuns(yes) ->
    {fun(Tab, Args) -> dets_sync_open(Tab, Args) end,
     fun(Tab) -> dets_sync_close(Tab) end};
mkfuns(no) ->
    {fun(Tab, Args) -> dets:open_file(Tab, Args) end,
     fun(Tab) -> dets:close(Tab) end}.

disk_type(Tab) ->
    disk_type(Tab, val({Tab, setorbag})).

disk_type(_Tab, ordered_set) ->
    set;
disk_type(_, Type) ->
    Type.

dets_sync_open(Tab, Ref, File) ->
    Args = [{file, File},
	    {keypos, 2},
	    {repair, mnesia_monitor:get_env(auto_repair)},
	    {type, disk_type(Tab)}],
    dets_sync_open(Ref, Args).

lock_table(Tab) ->
    global:set_lock({{mnesia_table_lock, Tab}, self()}, [node()], infinity).
%    dbg_out("dets_sync_open: ~p ~p~n", [T, self()]),

unlock_table(Tab) ->
    global:del_lock({{mnesia_table_lock, Tab}, self()}, [node()]).
%    dbg_out("unlock_table: ~p ~p~n", [T, self()]),

dets_sync_open(Tab, Args) ->
    lock_table(Tab),
    case dets:open_file(Tab, Args) of
	{ok, Tab} ->
	    {ok, Tab};
	Other ->
	    dets_sync_close(Tab),
	    Other
    end.

dets_sync_close(Tab) ->
    catch dets:close(Tab),
    unlock_table(Tab),
    ok.

cleanup_tmp_files([Tab | Tabs]) ->
    dets_sync_close(Tab),
    file:delete(tab2tmp(Tab)),
    cleanup_tmp_files(Tabs);
cleanup_tmp_files([]) ->
    ok.

%% Returns a list of bad tables
swap_tmp_files([Tab | Tabs]) ->
    dets_sync_close(Tab),
    Tmp = tab2tmp(Tab),
    Dat = tab2dat(Tab),
    case file:rename(Tmp, Dat) of
	ok ->
	    swap_tmp_files(Tabs);
	_ -> 
	    file:delete(Tmp),
	    [Tab | swap_tmp_files(Tabs)]
    end;
swap_tmp_files([]) ->
    [].

readable_indecies(Tab) ->
    val({Tab, index}).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Managing conditional debug functions
%%
%% The main idea with the debug_fun's is to allow test programs
%% to control the internal behaviour of Mnesia. This is needed
%% to make the test programs independent of system load, swapping
%% and other circumstances that may affect the behaviour of Mnesia.
%%
%% First should calls to ?eval_debug_fun be inserted at well
%% defined places in Mnesia's code. E.g. in critical situations
%% of startup, transaction commit, backups etc.
%%
%% Then compile Mnesia with the compiler option 'debug'.
%%
%% In test programs ?activate_debug_fun should be called
%% in order to bind a fun to the debug identifier stated
%% in the call to ?eval_debug_fun.
%%
%% If eval_debug_fun finds that the fun is activated it
%% invokes the fun as NewContext = Fun(PreviousContext, EvalContext)
%% and replaces the PreviousContext with the NewContext.
%% The initial context of a debug_fun is given as argument to
%% activate_debug_fun.

-define(DEBUG_TAB, mnesia_debug).
-record(debug_info, {id, function, context, file, line}).

scratch_debug_fun() ->
    dbg_out("scratch_debug_fun(): ~p~n", [?DEBUG_TAB]),
    (catch ?ets_delete_table(?DEBUG_TAB)),
    ?ets_new_table(?DEBUG_TAB, [set, public, named_table, {keypos, 2}]).

activate_debug_fun(FunId, Fun, InitialContext, File, Line) ->
    Info = #debug_info{id = FunId,
		       function = Fun,
		       context = InitialContext,
		       file = File,
		       line = Line
		      },
    update_debug_info(Info).

update_debug_info(Info) ->
    case catch ?ets_insert(?DEBUG_TAB, Info) of
	{'EXIT', _} ->
	    scratch_debug_fun(),
	    ?ets_insert(?DEBUG_TAB, Info);
	_ ->
	    ok
    end,
    dbg_out("update_debug_info(~p)~n", [Info]),
    ok.

deactivate_debug_fun(FunId, _File, _Line) ->
    catch ?ets_delete(?DEBUG_TAB, FunId),
    ok.

eval_debug_fun(FunId, EvalContext, EvalFile, EvalLine) ->
    case catch ?ets_lookup(?DEBUG_TAB, FunId) of
	[] ->
	    ok;
	[Info] ->
	    OldContext = Info#debug_info.context,
	    dbg_out("~s(~p): ~w "
		    "activated in ~s(~p)~n  "
		    "eval_debug_fun(~w, ~w)~n",
		    [filename:basename(EvalFile), EvalLine, Info#debug_info.id,
		     filename:basename(Info#debug_info.file), Info#debug_info.line,
		     OldContext, EvalContext]),
	    Fun = Info#debug_info.function,
	    NewContext = Fun(OldContext, EvalContext),
	    
	    case catch ?ets_lookup(?DEBUG_TAB, FunId) of
		[Info] when NewContext /= OldContext ->
		    NewInfo = Info#debug_info{context = NewContext},
		    update_debug_info(NewInfo);
		_ ->
		    ok
	    end;
	{'EXIT', _} -> ok    
    end.
	
-ifdef(debug).
    is_debug_compiled() -> true.
-else.
    is_debug_compiled() -> false.
-endif.