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// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/socket/read_buffering_stream_socket.h"
#include <algorithm>
#include "base/logging.h"
#include "net/base/io_buffer.h"
namespace net {
ReadBufferingStreamSocket::ReadBufferingStreamSocket(
std::unique_ptr<StreamSocket> transport)
: WrappedStreamSocket(std::move(transport)) {}
ReadBufferingStreamSocket::~ReadBufferingStreamSocket() = default;
void ReadBufferingStreamSocket::BufferNextRead(int size) {
DCHECK(!user_read_buf_);
read_buffer_ = base::MakeRefCounted<GrowableIOBuffer>();
read_buffer_->SetCapacity(size);
buffer_full_ = false;
}
int ReadBufferingStreamSocket::Read(IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) {
DCHECK(!user_read_buf_);
if (!read_buffer_)
return transport_->Read(buf, buf_len, std::move(callback));
int rv = ReadIfReady(buf, buf_len, std::move(callback));
if (rv == ERR_IO_PENDING) {
user_read_buf_ = buf;
user_read_buf_len_ = buf_len;
}
return rv;
}
int ReadBufferingStreamSocket::ReadIfReady(IOBuffer* buf,
int buf_len,
CompletionOnceCallback callback) {
DCHECK(!user_read_buf_);
if (!read_buffer_)
return transport_->ReadIfReady(buf, buf_len, std::move(callback));
if (buffer_full_)
return CopyToCaller(buf, buf_len);
state_ = STATE_READ;
int rv = DoLoop(OK);
if (rv == OK) {
rv = CopyToCaller(buf, buf_len);
} else if (rv == ERR_IO_PENDING) {
user_read_callback_ = std::move(callback);
}
return rv;
}
int ReadBufferingStreamSocket::DoLoop(int result) {
int rv = result;
do {
State current_state = state_;
state_ = STATE_NONE;
switch (current_state) {
case STATE_READ:
rv = DoRead();
break;
case STATE_READ_COMPLETE:
rv = DoReadComplete(rv);
break;
case STATE_NONE:
default:
NOTREACHED() << "Unexpected state: " << current_state;
rv = ERR_UNEXPECTED;
break;
}
} while (rv != ERR_IO_PENDING && state_ != STATE_NONE);
return rv;
}
int ReadBufferingStreamSocket::DoRead() {
DCHECK(read_buffer_);
DCHECK(!buffer_full_);
state_ = STATE_READ_COMPLETE;
return transport_->Read(
read_buffer_.get(), read_buffer_->RemainingCapacity(),
base::BindOnce(&ReadBufferingStreamSocket::OnReadCompleted,
base::Unretained(this)));
}
int ReadBufferingStreamSocket::DoReadComplete(int result) {
state_ = STATE_NONE;
if (result <= 0)
return result;
read_buffer_->set_offset(read_buffer_->offset() + result);
if (read_buffer_->RemainingCapacity() > 0) {
// Keep reading until |read_buffer_| is full.
state_ = STATE_READ;
} else {
read_buffer_->set_offset(0);
buffer_full_ = true;
}
return OK;
}
void ReadBufferingStreamSocket::OnReadCompleted(int result) {
DCHECK_NE(ERR_IO_PENDING, result);
DCHECK(user_read_callback_);
result = DoLoop(result);
if (result == ERR_IO_PENDING)
return;
if (result == OK && user_read_buf_) {
// If the user called Read(), return the data to the caller.
result = CopyToCaller(user_read_buf_.get(), user_read_buf_len_);
user_read_buf_ = nullptr;
user_read_buf_len_ = 0;
}
std::move(user_read_callback_).Run(result);
}
int ReadBufferingStreamSocket::CopyToCaller(IOBuffer* buf, int buf_len) {
DCHECK(read_buffer_);
DCHECK(buffer_full_);
buf_len = std::min(buf_len, read_buffer_->RemainingCapacity());
memcpy(buf->data(), read_buffer_->data(), buf_len);
read_buffer_->set_offset(read_buffer_->offset() + buf_len);
if (read_buffer_->RemainingCapacity() == 0) {
read_buffer_ = nullptr;
buffer_full_ = false;
}
return buf_len;
}
} // namespace net
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