base/include/aemu/base/misc/IpcPipe.h

// Copyright 2018 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

#ifdef _MSC_VER
#include "aemu/base/msvc.h"
#endif

#include <sys/types.h>

namespace android {
namespace base {

// Create a unidirectional pipe with the read-end connected to |readPipe| and
// the write-end connected to |writePipe|. This is equivalent to calling the
// POSIX function:
//     pipe(&fds);
// On Windows this will not use TCP loopback or sockets but instead the _pipe
// call making this an efficient form of communication on all platforms.
int ipcPipeCreate(int* readPipe, int* writePipe);

// Closes one end of a pipe. The ends of the pipe need to be closed separately.
void ipcPipeClose(int pipe);

// Try to read up to |bufferLen| bytes from |pipe| into |buffer|.
// Return the number of bytes actually read, 0 in case of disconnection,
// or -1/errno in case of error. Note that this loops around EINTR as
// a convenience. Only works on the read end of a pipe.
ssize_t ipcPipeRead(int pipe, void* buffer, size_t bufferLen);

// Try to write up to |bufferLen| bytes to |pipe| from |buffer|.
// Return the number of bytes actually written, 0 in case of disconnection,
// or -1/errno in case of error. Note that this loops around EINTR as
// a convenience. Only works on the write end of a pipe.
ssize_t ipcPipeWrite(int pipe, const void* buffer, size_t bufferLen);

}  // namespace base
}  // namespace android