chromium/net/socket/socket_bio_adapter.h

// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_SOCKET_SOCKET_BIO_ADAPTER_H_
#define NET_SOCKET_SOCKET_BIO_ADAPTER_H_

#include "base/containers/span.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "net/base/completion_repeating_callback.h"
#include "net/base/net_errors.h"
#include "net/base/net_export.h"
#include "third_party/boringssl/src/include/openssl/base.h"

namespace net {

class GrowableIOBuffer;
class IOBuffer;
class StreamSocket;

// An adapter to convert between StreamSocket and OpenSSL BIO I/O models.
//
// BIO exposes a UNIX-like interface where BIO_read and BIO_write may either
// succeed synchronously or be retried (with no memory between calls).
// StreamSocket exposes an asynchronous interface where an asynchronous
// operation continues running and completes with a callback.
//
// For reading, SocketBIOAdapter maintains a buffer to pass to
// StreamSocket::Read. Once that Read completes, BIO_read synchronously drains
// the buffer and signals BIO_should_read once empty.
//
// For writing, SocketBIOAdapter maintains a ring buffer of data to be written
// to the StreamSocket. BIO_write synchronously copies data into the buffer or
// signals BIO_should_write if the buffer is full. The ring buffer is drained
// asynchronously into the socket. Note this means write errors are reported at
// a later BIO_write.
//
// To work around this delay, write errors are also surfaced out of
// BIO_read. Otherwise a failure in the final BIO_write of an application may go
// unnoticed. If this occurs, OnReadReady will be signaled as if it were a read
// error. See https://crbug.com/249848.
class NET_EXPORT_PRIVATE SocketBIOAdapter { … };

}  // namespace net

#endif  // NET_SOCKET_SOCKET_BIO_ADAPTER_H_