comparison osx/include/capnp/ez-rpc.h @ 134:41e769c91eca

Add Capnp and KJ builds for OSX

+// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
+// Licensed under the MIT License:
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#ifndef CAPNP_EZ_RPC_H_
+#define CAPNP_EZ_RPC_H_
+
+#if defined(__GNUC__) && !defined(CAPNP_HEADER_WARNINGS)
+#pragma GCC system_header
+#endif
+
+#include "rpc.h"
+#include "message.h"
+
+struct sockaddr;
+
+namespace kj { class AsyncIoProvider; class LowLevelAsyncIoProvider; }
+
+namespace capnp {
+
+class EzRpcContext;
+
+class EzRpcClient {
+  // Super-simple interface for setting up a Cap'n Proto RPC client.  Example:
+  //
+  //     # Cap'n Proto schema
+  //     interface Adder {
+  //       add @0 (left :Int32, right :Int32) -> (value :Int32);
+  //     }
+  //
+  //     // C++ client
+  //     int main() {
+  //       capnp::EzRpcClient client("localhost:3456");
+  //       Adder::Client adder = client.getMain<Adder>();
+  //       auto request = adder.addRequest();
+  //       request.setLeft(12);
+  //       request.setRight(34);
+  //       auto response = request.send().wait(client.getWaitScope());
+  //       assert(response.getValue() == 46);
+  //       return 0;
+  //     }
+  //
+  //     // C++ server
+  //     class AdderImpl final: public Adder::Server {
+  //     public:
+  //       kj::Promise<void> add(AddContext context) override {
+  //         auto params = context.getParams();
+  //         context.getResults().setValue(params.getLeft() + params.getRight());
+  //         return kj::READY_NOW;
+  //       }
+  //     };
+  //
+  //     int main() {
+  //       capnp::EzRpcServer server(kj::heap<AdderImpl>(), "*:3456");
+  //       kj::NEVER_DONE.wait(server.getWaitScope());
+  //     }
+  //
+  // This interface is easy, but it hides a lot of useful features available from the lower-level
+  // classes:
+  // - The server can only export a small set of public, singleton capabilities under well-known
+  //   string names.  This is fine for transient services where no state needs to be kept between
+  //   connections, but hides the power of Cap'n Proto when it comes to long-lived resources.
+  // - EzRpcClient/EzRpcServer automatically set up a `kj::EventLoop` and make it current for the
+  //   thread.  Only one `kj::EventLoop` can exist per thread, so you cannot use these interfaces
+  //   if you wish to set up your own event loop.  (However, you can safely create multiple
+  //   EzRpcClient / EzRpcServer objects in a single thread; they will make sure to make no more
+  //   than one EventLoop.)
+  // - These classes only support simple two-party connections, not multilateral VatNetworks.
+  // - These classes only support communication over a raw, unencrypted socket.  If you want to
+  //   build on an abstract stream (perhaps one which supports encryption), you must use the
+  //   lower-level interfaces.
+  //
+  // Some of these restrictions will probably be lifted in future versions, but some things will
+  // always require using the low-level interfaces directly.  If you are interested in working
+  // at a lower level, start by looking at these interfaces:
+  // - `kj::setupAsyncIo()` in `kj/async-io.h`.
+  // - `RpcSystem` in `capnp/rpc.h`.
+  // - `TwoPartyVatNetwork` in `capnp/rpc-twoparty.h`.
+
+public:
+  explicit EzRpcClient(kj::StringPtr serverAddress, uint defaultPort = 0,
+                       ReaderOptions readerOpts = ReaderOptions());
+  // Construct a new EzRpcClient and connect to the given address.  The connection is formed in
+  // the background -- if it fails, calls to capabilities returned by importCap() will fail with an
+  // appropriate exception.
+  //
+  // `defaultPort` is the IP port number to use if `serverAddress` does not include it explicitly.
+  // If unspecified, the port is required in `serverAddress`.
+  //
+  // The address is parsed by `kj::Network` in `kj/async-io.h`.  See that interface for more info
+  // on the address format, but basically it's what you'd expect.
+  //
+  // `readerOpts` is the ReaderOptions structure used to read each incoming message on the
+  // connection. Setting this may be necessary if you need to receive very large individual
+  // messages or messages. However, it is recommended that you instead think about how to change
+  // your protocol to send large data blobs in multiple small chunks -- this is much better for
+  // both security and performance. See `ReaderOptions` in `message.h` for more details.
+
+  EzRpcClient(const struct sockaddr* serverAddress, uint addrSize,
+              ReaderOptions readerOpts = ReaderOptions());
+  // Like the above constructor, but connects to an already-resolved socket address.  Any address
+  // format supported by `kj::Network` in `kj/async-io.h` is accepted.
+
+  explicit EzRpcClient(int socketFd, ReaderOptions readerOpts = ReaderOptions());
+  // Create a client on top of an already-connected socket.
+  // `readerOpts` acts as in the first constructor.
+
+  ~EzRpcClient() noexcept(false);
+
+  template <typename Type>
+  typename Type::Client getMain();
+  Capability::Client getMain();
+  // Get the server's main (aka "bootstrap") interface.
+
+  template <typename Type>
+  typename Type::Client importCap(kj::StringPtr name)
+      KJ_DEPRECATED("Change your server to export a main interface, then use getMain() instead.");
+  Capability::Client importCap(kj::StringPtr name)
+      KJ_DEPRECATED("Change your server to export a main interface, then use getMain() instead.");
+  // ** DEPRECATED **
+  //
+  // Ask the sever for the capability with the given name.  You may specify a type to automatically
+  // down-cast to that type.  It is up to you to specify the correct expected type.
+  //
+  // Named interfaces are deprecated. The new preferred usage pattern is for the server to export
+  // a "main" interface which itself has methods for getting any other interfaces.
+
+  kj::WaitScope& getWaitScope();
+  // Get the `WaitScope` for the client's `EventLoop`, which allows you to synchronously wait on
+  // promises.
+
+  kj::AsyncIoProvider& getIoProvider();
+  // Get the underlying AsyncIoProvider set up by the RPC system.  This is useful if you want
+  // to do some non-RPC I/O in asynchronous fashion.
+
+  kj::LowLevelAsyncIoProvider& getLowLevelIoProvider();
+  // Get the underlying LowLevelAsyncIoProvider set up by the RPC system.  This is useful if you
+  // want to do some non-RPC I/O in asynchronous fashion.
+
+private:
+  struct Impl;
+  kj::Own<Impl> impl;
+};
+
+class EzRpcServer {
+  // The server counterpart to `EzRpcClient`.  See `EzRpcClient` for an example.
+
+public:
+  explicit EzRpcServer(Capability::Client mainInterface, kj::StringPtr bindAddress,
+                       uint defaultPort = 0, ReaderOptions readerOpts = ReaderOptions());
+  // Construct a new `EzRpcServer` that binds to the given address.  An address of "*" means to
+  // bind to all local addresses.
+  //
+  // `defaultPort` is the IP port number to use if `serverAddress` does not include it explicitly.
+  // If unspecified, a port is chosen automatically, and you must call getPort() to find out what
+  // it is.
+  //
+  // The address is parsed by `kj::Network` in `kj/async-io.h`.  See that interface for more info
+  // on the address format, but basically it's what you'd expect.
+  //
+  // The server might not begin listening immediately, especially if `bindAddress` needs to be
+  // resolved.  If you need to wait until the server is definitely up, wait on the promise returned
+  // by `getPort()`.
+  //
+  // `readerOpts` is the ReaderOptions structure used to read each incoming message on the
+  // connection. Setting this may be necessary if you need to receive very large individual
+  // messages or messages. However, it is recommended that you instead think about how to change
+  // your protocol to send large data blobs in multiple small chunks -- this is much better for
+  // both security and performance. See `ReaderOptions` in `message.h` for more details.
+
+  EzRpcServer(Capability::Client mainInterface, struct sockaddr* bindAddress, uint addrSize,
+              ReaderOptions readerOpts = ReaderOptions());
+  // Like the above constructor, but binds to an already-resolved socket address.  Any address
+  // format supported by `kj::Network` in `kj/async-io.h` is accepted.
+
+  EzRpcServer(Capability::Client mainInterface, int socketFd, uint port,
+              ReaderOptions readerOpts = ReaderOptions());
+  // Create a server on top of an already-listening socket (i.e. one on which accept() may be
+  // called).  `port` is returned by `getPort()` -- it serves no other purpose.
+  // `readerOpts` acts as in the other two above constructors.
+
+  explicit EzRpcServer(kj::StringPtr bindAddress, uint defaultPort = 0,
+                       ReaderOptions readerOpts = ReaderOptions())
+      KJ_DEPRECATED("Please specify a main interface for your server.");
+  EzRpcServer(struct sockaddr* bindAddress, uint addrSize,
+              ReaderOptions readerOpts = ReaderOptions())
+      KJ_DEPRECATED("Please specify a main interface for your server.");
+  EzRpcServer(int socketFd, uint port, ReaderOptions readerOpts = ReaderOptions())
+      KJ_DEPRECATED("Please specify a main interface for your server.");
+
+  ~EzRpcServer() noexcept(false);
+
+  void exportCap(kj::StringPtr name, Capability::Client cap);
+  // Export a capability publicly under the given name, so that clients can import it.
+  //
+  // Keep in mind that you can implicitly convert `kj::Own<MyType::Server>&&` to
+  // `Capability::Client`, so it's typical to pass something like
+  // `kj::heap<MyImplementation>(<constructor params>)` as the second parameter.
+
+  kj::Promise<uint> getPort();
+  // Get the IP port number on which this server is listening.  This promise won't resolve until
+  // the server is actually listening.  If the address was not an IP address (e.g. it was a Unix
+  // domain socket) then getPort() resolves to zero.
+
+  kj::WaitScope& getWaitScope();
+  // Get the `WaitScope` for the client's `EventLoop`, which allows you to synchronously wait on
+  // promises.
+
+  kj::AsyncIoProvider& getIoProvider();
+  // Get the underlying AsyncIoProvider set up by the RPC system.  This is useful if you want
+  // to do some non-RPC I/O in asynchronous fashion.
+
+  kj::LowLevelAsyncIoProvider& getLowLevelIoProvider();
+  // Get the underlying LowLevelAsyncIoProvider set up by the RPC system.  This is useful if you
+  // want to do some non-RPC I/O in asynchronous fashion.
+
+private:
+  struct Impl;
+  kj::Own<Impl> impl;
+};
+
+// =======================================================================================
+// inline implementation details
+
+template <typename Type>
+inline typename Type::Client EzRpcClient::getMain() {
+  return getMain().castAs<Type>();
+}
+
+template <typename Type>
+inline typename Type::Client EzRpcClient::importCap(kj::StringPtr name) {
+  return importCap(name).castAs<Type>();
+}
+
+}  // namespace capnp
+
+#endif  // CAPNP_EZ_RPC_H_