copy wangle back into folly

[folly.git] / folly / wangle / channel / Handler.h

diff --git a/folly/wangle/channel/Handler.h b/folly/wangle/channel/Handler.h
new file mode 100644 (file)
index 0000000..2080c2c
--- /dev/null
+++ b/folly/wangle/channel/Handler.h
@@ -0,0 +1,173 @@
+/*
+ * Copyright 2015 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <folly/futures/Future.h>
+#include <folly/wangle/channel/Pipeline.h>
+#include <folly/io/IOBuf.h>
+#include <folly/io/IOBufQueue.h>
+
+namespace folly { namespace wangle {
+
+template <class Context>
+class HandlerBase {
+ public:
+  virtual ~HandlerBase() {}
+
+  virtual void attachPipeline(Context* ctx) {}
+  virtual void detachPipeline(Context* ctx) {}
+
+  Context* getContext() {
+    if (attachCount_ != 1) {
+      return nullptr;
+    }
+    CHECK(ctx_);
+    return ctx_;
+  }
+
+ private:
+  friend PipelineContext;
+  uint64_t attachCount_{0};
+  Context* ctx_{nullptr};
+};
+
+template <class Rin, class Rout = Rin, class Win = Rout, class Wout = Rin>
+class Handler : public HandlerBase<HandlerContext<Rout, Wout>> {
+ public:
+  static const HandlerDir dir = HandlerDir::BOTH;
+
+  typedef Rin rin;
+  typedef Rout rout;
+  typedef Win win;
+  typedef Wout wout;
+  typedef HandlerContext<Rout, Wout> Context;
+  virtual ~Handler() {}
+
+  virtual void read(Context* ctx, Rin msg) = 0;
+  virtual void readEOF(Context* ctx) {
+    ctx->fireReadEOF();
+  }
+  virtual void readException(Context* ctx, exception_wrapper e) {
+    ctx->fireReadException(std::move(e));
+  }
+  virtual void transportActive(Context* ctx) {
+    ctx->fireTransportActive();
+  }
+  virtual void transportInactive(Context* ctx) {
+    ctx->fireTransportInactive();
+  }
+
+  virtual Future<void> write(Context* ctx, Win msg) = 0;
+  virtual Future<void> close(Context* ctx) {
+    return ctx->fireClose();
+  }
+
+  /*
+  // Other sorts of things we might want, all shamelessly stolen from Netty
+  // inbound
+  virtual void exceptionCaught(
+      HandlerContext* ctx,
+      exception_wrapper e) {}
+  virtual void channelRegistered(HandlerContext* ctx) {}
+  virtual void channelUnregistered(HandlerContext* ctx) {}
+  virtual void channelReadComplete(HandlerContext* ctx) {}
+  virtual void userEventTriggered(HandlerContext* ctx, void* evt) {}
+  virtual void channelWritabilityChanged(HandlerContext* ctx) {}
+
+  // outbound
+  virtual Future<void> bind(
+      HandlerContext* ctx,
+      SocketAddress localAddress) {}
+  virtual Future<void> connect(
+          HandlerContext* ctx,
+          SocketAddress remoteAddress, SocketAddress localAddress) {}
+  virtual Future<void> disconnect(HandlerContext* ctx) {}
+  virtual Future<void> deregister(HandlerContext* ctx) {}
+  virtual Future<void> read(HandlerContext* ctx) {}
+  virtual void flush(HandlerContext* ctx) {}
+  */
+};
+
+template <class Rin, class Rout = Rin>
+class InboundHandler : public HandlerBase<InboundHandlerContext<Rout>> {
+ public:
+  static const HandlerDir dir = HandlerDir::IN;
+
+  typedef Rin rin;
+  typedef Rout rout;
+  typedef Nothing win;
+  typedef Nothing wout;
+  typedef InboundHandlerContext<Rout> Context;
+  virtual ~InboundHandler() {}
+
+  virtual void read(Context* ctx, Rin msg) = 0;
+  virtual void readEOF(Context* ctx) {
+    ctx->fireReadEOF();
+  }
+  virtual void readException(Context* ctx, exception_wrapper e) {
+    ctx->fireReadException(std::move(e));
+  }
+  virtual void transportActive(Context* ctx) {
+    ctx->fireTransportActive();
+  }
+  virtual void transportInactive(Context* ctx) {
+    ctx->fireTransportInactive();
+  }
+};
+
+template <class Win, class Wout = Win>
+class OutboundHandler : public HandlerBase<OutboundHandlerContext<Wout>> {
+ public:
+  static const HandlerDir dir = HandlerDir::OUT;
+
+  typedef Nothing rin;
+  typedef Nothing rout;
+  typedef Win win;
+  typedef Wout wout;
+  typedef OutboundHandlerContext<Wout> Context;
+  virtual ~OutboundHandler() {}
+
+  virtual Future<void> write(Context* ctx, Win msg) = 0;
+  virtual Future<void> close(Context* ctx) {
+    return ctx->fireClose();
+  }
+};
+
+template <class R, class W = R>
+class HandlerAdapter : public Handler<R, R, W, W> {
+ public:
+  typedef typename Handler<R, R, W, W>::Context Context;
+
+  void read(Context* ctx, R msg) override {
+    ctx->fireRead(std::forward<R>(msg));
+  }
+
+  Future<void> write(Context* ctx, W msg) override {
+    return ctx->fireWrite(std::forward<W>(msg));
+  }
+};
+
+typedef HandlerAdapter<IOBufQueue&, std::unique_ptr<IOBuf>>
+BytesToBytesHandler;
+
+typedef InboundHandler<IOBufQueue&, std::unique_ptr<IOBuf>>
+InboundBytesToBytesHandler;
+
+typedef OutboundHandler<std::unique_ptr<IOBuf>>
+OutboundBytesToBytesHandler;
+
+}}