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%% The contents of this file are subject to the Mozilla Public License
%% Version 1.1 (the "License"); you may not use this file except in
%% compliance with the License. You may obtain a copy of the License
%% at http://www.mozilla.org/MPL/
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and
%% limitations under the License.
%%
%% The Original Code is RabbitMQ.
%%
%% The Initial Developer of the Original Code is VMware, Inc.
%% Copyright (c) 2007-2011 VMware, Inc. All rights reserved.
%%
-module(rabbit_exchange_type_headers).
-include("rabbit.hrl").
-include("rabbit_framing.hrl").
-behaviour(rabbit_exchange_type).
-export([description/0, route/2]).
-export([validate/1, start/3, delete/3, add_bindings/3,
remove_bindings/3, assert_args_equivalence/2]).
-include("rabbit_exchange_type_spec.hrl").
-rabbit_boot_step({?MODULE,
[{description, "exchange type headers"},
{mfa, {rabbit_registry, register,
[exchange, <<"headers">>, ?MODULE]}},
{requires, rabbit_registry},
{enables, kernel_ready}]}).
-ifdef(use_specs).
-spec(headers_match/2 :: (rabbit_framing:amqp_table(),
rabbit_framing:amqp_table()) -> boolean()).
-endif.
description() ->
[{name, <<"headers">>},
{description, <<"AMQP headers exchange, as per the AMQP specification">>}].
route(#exchange{name = Name},
#delivery{message = #basic_message{content = Content}}) ->
Headers = case (Content#content.properties)#'P_basic'.headers of
undefined -> [];
H -> rabbit_misc:sort_field_table(H)
end,
rabbit_router:match_bindings(
Name, fun (#binding{args = Spec}) -> headers_match(Spec, Headers) end).
default_headers_match_kind() -> all.
parse_x_match(<<"all">>) -> all;
parse_x_match(<<"any">>) -> any;
parse_x_match(Other) ->
rabbit_log:warning("Invalid x-match field value ~p; expected all or any",
[Other]),
default_headers_match_kind().
%% Horrendous matching algorithm. Depends for its merge-like
%% (linear-time) behaviour on the lists:keysort
%% (rabbit_misc:sort_field_table) that route/1 and
%% rabbit_binding:{add,remove}/2 do.
%%
%% !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
%% In other words: REQUIRES BOTH PATTERN AND DATA TO BE SORTED ASCENDING BY KEY.
%% !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
%%
headers_match(Pattern, Data) ->
MatchKind = case lists:keysearch(<<"x-match">>, 1, Pattern) of
{value, {_, longstr, MK}} -> parse_x_match(MK);
{value, {_, Type, MK}} ->
rabbit_log:warning("Invalid x-match field type ~p "
"(value ~p); expected longstr",
[Type, MK]),
default_headers_match_kind();
_ -> default_headers_match_kind()
end,
headers_match(Pattern, Data, true, false, MatchKind).
headers_match([], _Data, AllMatch, _AnyMatch, all) ->
AllMatch;
headers_match([], _Data, _AllMatch, AnyMatch, any) ->
AnyMatch;
headers_match([{<<"x-", _/binary>>, _PT, _PV} | PRest], Data,
AllMatch, AnyMatch, MatchKind) ->
headers_match(PRest, Data, AllMatch, AnyMatch, MatchKind);
headers_match(_Pattern, [], _AllMatch, AnyMatch, MatchKind) ->
headers_match([], [], false, AnyMatch, MatchKind);
headers_match(Pattern = [{PK, _PT, _PV} | _], [{DK, _DT, _DV} | DRest],
AllMatch, AnyMatch, MatchKind) when PK > DK ->
headers_match(Pattern, DRest, AllMatch, AnyMatch, MatchKind);
headers_match([{PK, _PT, _PV} | PRest], Data = [{DK, _DT, _DV} | _],
_AllMatch, AnyMatch, MatchKind) when PK < DK ->
headers_match(PRest, Data, false, AnyMatch, MatchKind);
headers_match([{PK, PT, PV} | PRest], [{DK, DT, DV} | DRest],
AllMatch, AnyMatch, MatchKind) when PK == DK ->
{AllMatch1, AnyMatch1} =
if
%% It's not properly specified, but a "no value" in a
%% pattern field is supposed to mean simple presence of
%% the corresponding data field. I've interpreted that to
%% mean a type of "void" for the pattern field.
PT == void -> {AllMatch, true};
%% Similarly, it's not specified, but I assume that a
%% mismatched type causes a mismatched value.
PT =/= DT -> {false, AnyMatch};
PV == DV -> {AllMatch, true};
true -> {false, AnyMatch}
end,
headers_match(PRest, DRest, AllMatch1, AnyMatch1, MatchKind).
validate(_X) -> ok.
start(_Tx, _X, _Bs) -> ok.
delete(_Tx, _X, _Bs) -> ok.
add_bindings(_Tx, _X, _Bs) -> ok.
remove_bindings(_Tx, _X, _Bs) -> ok.
assert_args_equivalence(X, Args) ->
rabbit_exchange:assert_args_equivalence(X, Args).
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