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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).
-include("rabbit.hrl").
-include("rabbit_framing.hrl").
-export([recover/0, callback/3, declare/6,
assert_equivalence/6, assert_args_equivalence/2, check_type/1,
lookup/1, lookup_or_die/1, list/1,
info_keys/0, info/1, info/2, info_all/1, info_all/2,
publish/2, delete/2]).
%% this must be run inside a mnesia tx
-export([maybe_auto_delete/1]).
%%----------------------------------------------------------------------------
-ifdef(use_specs).
-export_type([name/0, type/0]).
-type(name() :: rabbit_types:r('exchange')).
-type(type() :: atom()).
-type(fun_name() :: atom()).
-spec(recover/0 :: () -> [name()]).
-spec(callback/3:: (rabbit_types:exchange(), fun_name(), [any()]) -> 'ok').
-spec(declare/6 ::
(name(), type(), boolean(), boolean(), boolean(),
rabbit_framing:amqp_table())
-> rabbit_types:exchange()).
-spec(check_type/1 ::
(binary()) -> atom() | rabbit_types:connection_exit()).
-spec(assert_equivalence/6 ::
(rabbit_types:exchange(), atom(), boolean(), boolean(), boolean(),
rabbit_framing:amqp_table())
-> 'ok' | rabbit_types:connection_exit()).
-spec(assert_args_equivalence/2 ::
(rabbit_types:exchange(), rabbit_framing:amqp_table())
-> 'ok' | rabbit_types:connection_exit()).
-spec(lookup/1 ::
(name()) -> rabbit_types:ok(rabbit_types:exchange()) |
rabbit_types:error('not_found')).
-spec(lookup_or_die/1 ::
(name()) -> rabbit_types:exchange() |
rabbit_types:channel_exit()).
-spec(list/1 :: (rabbit_types:vhost()) -> [rabbit_types:exchange()]).
-spec(info_keys/0 :: () -> rabbit_types:info_keys()).
-spec(info/1 :: (rabbit_types:exchange()) -> rabbit_types:infos()).
-spec(info/2 ::
(rabbit_types:exchange(), rabbit_types:info_keys())
-> rabbit_types:infos()).
-spec(info_all/1 :: (rabbit_types:vhost()) -> [rabbit_types:infos()]).
-spec(info_all/2 ::(rabbit_types:vhost(), rabbit_types:info_keys())
-> [rabbit_types:infos()]).
-spec(publish/2 :: (rabbit_types:exchange(), rabbit_types:delivery())
-> {rabbit_router:routing_result(), [pid()]}).
-spec(delete/2 ::
(name(), boolean())-> 'ok' |
rabbit_types:error('not_found') |
rabbit_types:error('in_use')).
-spec(maybe_auto_delete/1::
(rabbit_types:exchange())
-> 'not_deleted' | {'deleted', rabbit_binding:deletions()}).
-endif.
%%----------------------------------------------------------------------------
-define(INFO_KEYS, [name, type, durable, auto_delete, internal, arguments]).
recover() ->
Xs = rabbit_misc:table_filter(
fun (#exchange{name = XName}) ->
mnesia:read({rabbit_exchange, XName}) =:= []
end,
fun (X, Tx) -> case Tx of
true -> ok = mnesia:write(rabbit_exchange,
X, write);
false -> ok
end,
rabbit_exchange:callback(X, create, [Tx, X])
end,
rabbit_durable_exchange),
[XName || #exchange{name = XName} <- Xs].
callback(#exchange{type = XType}, Fun, Args) ->
apply(type_to_module(XType), Fun, Args).
declare(XName, Type, Durable, AutoDelete, Internal, Args) ->
X = #exchange{name = XName,
type = Type,
durable = Durable,
auto_delete = AutoDelete,
internal = Internal,
arguments = Args},
%% We want to upset things if it isn't ok
ok = (type_to_module(Type)):validate(X),
rabbit_misc:execute_mnesia_transaction(
fun () ->
case mnesia:wread({rabbit_exchange, XName}) of
[] ->
ok = mnesia:write(rabbit_exchange, X, write),
ok = case Durable of
true -> mnesia:write(rabbit_durable_exchange,
X, write);
false -> ok
end,
{new, X};
[ExistingX] ->
{existing, ExistingX}
end
end,
fun ({new, Exchange}, Tx) ->
ok = (type_to_module(Type)):create(Tx, Exchange),
rabbit_event:notify_if(not Tx, exchange_created, info(Exchange)),
Exchange;
({existing, Exchange}, _Tx) ->
Exchange;
(Err, _Tx) ->
Err
end).
%% Used with binaries sent over the wire; the type may not exist.
check_type(TypeBin) ->
case rabbit_registry:binary_to_type(TypeBin) of
{error, not_found} ->
rabbit_misc:protocol_error(
command_invalid, "unknown exchange type '~s'", [TypeBin]);
T ->
case rabbit_registry:lookup_module(exchange, T) of
{error, not_found} -> rabbit_misc:protocol_error(
command_invalid,
"invalid exchange type '~s'", [T]);
{ok, _Module} -> T
end
end.
assert_equivalence(X = #exchange{ durable = Durable,
auto_delete = AutoDelete,
internal = Internal,
type = Type},
Type, Durable, AutoDelete, Internal, RequiredArgs) ->
(type_to_module(Type)):assert_args_equivalence(X, RequiredArgs);
assert_equivalence(#exchange{ name = Name },
_Type, _Durable, _Internal, _AutoDelete, _Args) ->
rabbit_misc:protocol_error(
precondition_failed,
"cannot redeclare ~s with different type, durable, "
"internal or autodelete value",
[rabbit_misc:rs(Name)]).
assert_args_equivalence(#exchange{ name = Name, arguments = Args },
RequiredArgs) ->
%% The spec says "Arguments are compared for semantic
%% equivalence". The only arg we care about is
%% "alternate-exchange".
rabbit_misc:assert_args_equivalence(Args, RequiredArgs, Name,
[<<"alternate-exchange">>]).
lookup(Name) ->
rabbit_misc:dirty_read({rabbit_exchange, Name}).
lookup_or_die(Name) ->
case lookup(Name) of
{ok, X} -> X;
{error, not_found} -> rabbit_misc:not_found(Name)
end.
list(VHostPath) ->
mnesia:dirty_match_object(
rabbit_exchange,
#exchange{name = rabbit_misc:r(VHostPath, exchange), _ = '_'}).
info_keys() -> ?INFO_KEYS.
map(VHostPath, F) ->
%% TODO: there is scope for optimisation here, e.g. using a
%% cursor, parallelising the function invocation
lists:map(F, list(VHostPath)).
infos(Items, X) -> [{Item, i(Item, X)} || Item <- Items].
i(name, #exchange{name = Name}) -> Name;
i(type, #exchange{type = Type}) -> Type;
i(durable, #exchange{durable = Durable}) -> Durable;
i(auto_delete, #exchange{auto_delete = AutoDelete}) -> AutoDelete;
i(internal, #exchange{internal = Internal}) -> Internal;
i(arguments, #exchange{arguments = Arguments}) -> Arguments;
i(Item, _) -> throw({bad_argument, Item}).
info(X = #exchange{}) -> infos(?INFO_KEYS, X).
info(X = #exchange{}, Items) -> infos(Items, X).
info_all(VHostPath) -> map(VHostPath, fun (X) -> info(X) end).
info_all(VHostPath, Items) -> map(VHostPath, fun (X) -> info(X, Items) end).
publish(X = #exchange{name = XName}, Delivery) ->
rabbit_router:deliver(
route(Delivery, {queue:from_list([X]), XName, []}),
Delivery).
route(Delivery, {WorkList, SeenXs, QNames}) ->
case queue:out(WorkList) of
{empty, _WorkList} ->
lists:usort(QNames);
{{value, X = #exchange{type = Type}}, WorkList1} ->
DstNames = process_alternate(
X, ((type_to_module(Type)):route(X, Delivery))),
route(Delivery,
lists:foldl(fun process_route/2, {WorkList1, SeenXs, QNames},
DstNames))
end.
process_alternate(#exchange{name = XName, arguments = Args}, []) ->
case rabbit_misc:r_arg(XName, exchange, Args, <<"alternate-exchange">>) of
undefined -> [];
AName -> [AName]
end;
process_alternate(_X, Results) ->
Results.
process_route(#resource{kind = exchange} = XName,
{_WorkList, XName, _QNames} = Acc) ->
Acc;
process_route(#resource{kind = exchange} = XName,
{WorkList, #resource{kind = exchange} = SeenX, QNames}) ->
{case lookup(XName) of
{ok, X} -> queue:in(X, WorkList);
{error, not_found} -> WorkList
end, gb_sets:from_list([SeenX, XName]), QNames};
process_route(#resource{kind = exchange} = XName,
{WorkList, SeenXs, QNames} = Acc) ->
case gb_sets:is_element(XName, SeenXs) of
true -> Acc;
false -> {case lookup(XName) of
{ok, X} -> queue:in(X, WorkList);
{error, not_found} -> WorkList
end, gb_sets:add_element(XName, SeenXs), QNames}
end;
process_route(#resource{kind = queue} = QName,
{WorkList, SeenXs, QNames}) ->
{WorkList, SeenXs, [QName | QNames]}.
call_with_exchange(XName, Fun, PrePostCommitFun) ->
rabbit_misc:execute_mnesia_transaction(
fun () -> case mnesia:read({rabbit_exchange, XName}) of
[] -> {error, not_found};
[X] -> Fun(X)
end
end, PrePostCommitFun).
delete(XName, IfUnused) ->
call_with_exchange(
XName,
case IfUnused of
true -> fun conditional_delete/1;
false -> fun unconditional_delete/1
end,
fun ({deleted, X, Bs, Deletions}, Tx) ->
ok = rabbit_binding:process_deletions(
rabbit_binding:add_deletion(
XName, {X, deleted, Bs}, Deletions), Tx);
(Error = {error, _InUseOrNotFound}, _Tx) ->
Error
end).
maybe_auto_delete(#exchange{auto_delete = false}) ->
not_deleted;
maybe_auto_delete(#exchange{auto_delete = true} = X) ->
case conditional_delete(X) of
{error, in_use} -> not_deleted;
{deleted, X, [], Deletions} -> {deleted, Deletions}
end.
conditional_delete(X = #exchange{name = XName}) ->
case rabbit_binding:has_for_source(XName) of
false -> unconditional_delete(X);
true -> {error, in_use}
end.
unconditional_delete(X = #exchange{name = XName}) ->
ok = mnesia:delete({rabbit_durable_exchange, XName}),
ok = mnesia:delete({rabbit_exchange, XName}),
Bindings = rabbit_binding:remove_for_source(XName),
{deleted, X, Bindings, rabbit_binding:remove_for_destination(XName)}.
%% Used with atoms from records; e.g., the type is expected to exist.
type_to_module(T) ->
{ok, Module} = rabbit_registry:lookup_module(exchange, T),
Module.
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