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Correctly handle empty result with RSM

Fixes #2588
This commit is contained in:
Evgeniy Khramtsov 2018-09-02 00:37:07 +03:00
parent 88d0b71d58
commit 5c931d7004

View File

@ -738,39 +738,43 @@ get_items(Nidx, _From, undefined) ->
get_items(Nidx, _From, #rsm_set{max = Max, index = IncIndex,
'after' = After, before = Before}) ->
RItems = lists:keysort(#pubsub_item.creation,
mnesia:index_read(pubsub_item, Nidx, #pubsub_item.nodeidx)),
Count = length(RItems),
Limit = case Max of
undefined -> ?MAXITEMS;
_ -> Max
end,
{Offset, ItemsPage} =
case {IncIndex, Before, After} of
{I, undefined, undefined} ->
SubList = lists:nthtail(I, RItems),
{I, lists:sublist(SubList, Limit)};
{_, <<>>, undefined} ->
%% 2.5 Requesting the Last Page in a Result Set
SubList = lists:reverse(RItems),
{0, lists:sublist(SubList, Limit)};
{_, Stamp, undefined} ->
BeforeNow = encode_stamp(Stamp),
SubList = lists:dropwhile(
fun(#pubsub_item{creation = {Now, _}}) ->
Now >= BeforeNow
end, lists:reverse(RItems)),
{0, lists:sublist(SubList, Limit)};
{_, undefined, Stamp} ->
AfterNow = encode_stamp(Stamp),
SubList = lists:dropwhile(
fun(#pubsub_item{creation = {Now, _}}) ->
Now =< AfterNow
end, RItems),
{0, lists:sublist(SubList, Limit)}
end,
Rsm = rsm_page(Count, IncIndex, Offset, ItemsPage),
{result, {ItemsPage, Rsm}}.
case lists:keysort(#pubsub_item.creation,
mnesia:index_read(pubsub_item, Nidx, #pubsub_item.nodeidx)) of
[] ->
{result, {[], #rsm_set{count = 0}}};
RItems ->
Count = length(RItems),
Limit = case Max of
undefined -> ?MAXITEMS;
_ -> Max
end,
{Offset, ItemsPage} =
case {IncIndex, Before, After} of
{I, undefined, undefined} ->
SubList = lists:nthtail(I, RItems),
{I, lists:sublist(SubList, Limit)};
{_, <<>>, undefined} ->
%% 2.5 Requesting the Last Page in a Result Set
SubList = lists:reverse(RItems),
{0, lists:sublist(SubList, Limit)};
{_, Stamp, undefined} ->
BeforeNow = encode_stamp(Stamp),
SubList = lists:dropwhile(
fun(#pubsub_item{creation = {Now, _}}) ->
Now >= BeforeNow
end, lists:reverse(RItems)),
{0, lists:sublist(SubList, Limit)};
{_, undefined, Stamp} ->
AfterNow = encode_stamp(Stamp),
SubList = lists:dropwhile(
fun(#pubsub_item{creation = {Now, _}}) ->
Now =< AfterNow
end, RItems),
{0, lists:sublist(SubList, Limit)}
end,
Rsm = rsm_page(Count, IncIndex, Offset, ItemsPage),
{result, {ItemsPage, Rsm}}
end.
get_items(Nidx, JID, AccessModel, PresenceSubscription, RosterGroup, _SubId, RSM) ->
SubKey = jid:tolower(JID),
@ -920,6 +924,8 @@ first_in_list(Pred, [H | T]) ->
_ -> first_in_list(Pred, T)
end.
rsm_page(Count, _, _, []) ->
#rsm_set{count = Count};
rsm_page(Count, Index, Offset, Items) ->
FirstItem = hd(Items),
LastItem = lists:last(Items),