2 * Copyright 2015 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include <folly/wangle/channel/Handler.h>
19 #include <folly/wangle/service/Service.h>
21 namespace folly { namespace wangle {
24 * Dispatch a request, satisfying Promise `p` with the response;
25 * the returned Future is satisfied when the response is received:
26 * only one request is allowed at a time.
28 template <typename Pipeline, typename Req, typename Resp = Req>
29 class SerialClientDispatcher : public HandlerAdapter<Req, Resp>
30 , public Service<Req, Resp> {
32 typedef typename HandlerAdapter<Req, Resp>::Context Context;
34 ~SerialClientDispatcher() {
37 pipeline_->remove(this).finalize();
38 } catch (const std::invalid_argument& e) {
39 // not in pipeline; this is fine
44 void setPipeline(Pipeline* pipeline) {
46 pipeline->template remove<SerialClientDispatcher>();
47 } catch (const std::invalid_argument& e) {
48 // no existing dispatcher; this is fine
51 pipeline_->addBack(this);
52 pipeline_->finalize();
55 void read(Context* ctx, Req in) override {
57 p_->setValue(std::move(in));
61 virtual Future<Resp> operator()(Req arg) override {
66 auto f = p_->getFuture();
67 pipeline_->write(std::move(arg));
71 virtual Future<void> close() override {
72 return HandlerAdapter<Req, Resp>::close(nullptr);
75 virtual Future<void> close(Context* ctx) override {
76 return HandlerAdapter<Req, Resp>::close(ctx);
79 void detachPipeline(Context* ctx) override {
84 Pipeline* pipeline_{nullptr};
85 folly::Optional<Promise<Resp>> p_;