refactor(mgmt_api): `select_table`.

This commit is contained in:
JimMoen 2021-10-08 11:27:36 +08:00
parent b4433f77c8
commit 5daef544a0
1 changed files with 13 additions and 23 deletions

View File

@ -18,6 +18,8 @@
-include_lib("stdlib/include/qlc.hrl").
-define(FRESH_SELECT, fresh_select).
-export([ paginate/3
, paginate/4
]).
@ -217,32 +219,20 @@ traverse_n_by_one(Tab, K, MatchFun, Start, Limit, Acc) ->
end
end.
select_table(Tab, Ms, 0, Limit, FmtFun) ->
select_table(Tab, Ms, ?FRESH_SELECT, Limit, FmtFun)
when Limit > 0 ->
case ets:select(Tab, Ms, Limit) of
'$end_of_table' ->
{0, []};
{Rows, _} ->
{0, lists:map(FmtFun, lists:reverse(Rows))}
{[], ?FRESH_SELECT};
{RawResult, NContinuation} ->
{lists:map(FmtFun, lists:reverse(RawResult)), NContinuation}
end;
select_table(Tab, Ms, Start, Limit, FmtFun) ->
{NStart, Rows} = select_n_by_one(ets:select(Tab, Ms, Limit), Start, Limit, []),
{NStart, lists:map(FmtFun, Rows)}.
select_n_by_one('$end_of_table', Start, _Limit, Acc) ->
{Start, lists:flatten(lists:reverse(Acc))};
select_n_by_one(_, Start, _Limit = 0, Acc) ->
{Start, lists:flatten(lists:reverse(Acc))};
select_n_by_one({Rows0, Cons}, Start, Limit, Acc) ->
Rows = lists:reverse(Rows0),
case Start - length(Rows) of
N when N > 0 -> %% Skip
select_n_by_one(ets:select(Cons), N, Limit, Acc);
_ ->
Got = lists:sublist(Rows, Start+1, Limit),
NLimit = Limit - length(Got),
select_n_by_one(ets:select(Cons), 0, NLimit, [Got|Acc])
select_table(_Tab, _Ms, Continuation, _Limit, FmtFun) ->
case ets:select(Continuation) of
'$end_of_table' ->
{[], ?FRESH_SELECT};
{RawResult, NContinuation} ->
{lists:map(FmtFun, lists:reverse(RawResult)), NContinuation}
end.
%%--------------------------------------------------------------------