// Copyright (C) 2021 The Android Open Source Project // // 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 #include #include #include #ifdef _WIN32 #include typedef SSIZE_T ssize_t; #else #include #endif namespace android { namespace net { class AsyncDataChannel; // Callback function that will be used to notify that new data // can be read. using ReadCallback = std::function; // A connected asynchronous socket abstraction. // // This is really a simple data channel that can be used to read and write // data. Async Sockets are usually non-blocking posix/win sockets, but could be // other types of datachannels (gRPC, qemu pipe) class AsyncDataChannel { public: virtual ~AsyncDataChannel() = default; // Receive data in the given buffer. Properly handling EINTR where // applicable. // // Returns: // - >0: The number of bytes read. // - 0: The socket is closed, no further reads/write are possible // - <0: An error occurred. Details can be found in errno: // - EAGAIN: No data, try again later. // // Implementors should take care of translating EWOULDBLOCK into EAGAIN // if needed. virtual ssize_t Recv(uint8_t* buffer, uint64_t bufferSize) = 0; // Send data in the given buffer. Properly handling EINTR, EPIPE where // applicable. // // Returns: // - >0: The number of bytes written, this can be < bufferSize. // - <0: An error occurred. Details can be found in errno: // - EAGAIN: The write would block, try again later. // - EBADF: The connection is closed. // // Implementors should take care of translating EWOULDBLOCK into EAGAIN // if needed. virtual ssize_t Send(const uint8_t* buffer, uint64_t bufferSize) = 0; // True if this socket is connected virtual bool Connected() = 0; // Closes this socket. Upon return the following will hold: // // - No more ReadCallbacks will be invoked. // - Send/Recv calls will return 0. virtual void Close() = 0; // Registers the given callback to be invoked when a recv call can be made // to read data from this socket. The expectation is that a call to Recv will // not return EAGAIN. Returns false if registration of the watcher failed. // // Only one callback can be registered per socket. virtual bool WatchForNonBlockingRead( const ReadCallback& on_read_ready_callback) = 0; // Stops watching this socket, you will not receive any callbacks any longer. virtual void StopWatching() = 0; }; } // namespace net } // namespace android