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// Copyright (c) 2012 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 "tools/android/forwarder2/forwarder.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "base/eintr_wrapper.h"
#include "base/logging.h"
#include "base/safe_strerror_posix.h"
#include "tools/android/forwarder2/socket.h"
namespace forwarder2 {
namespace {
// Helper class to buffer reads and writes from one socket to another.
class BufferedCopier {
public:
// Does NOT own the pointers.
BufferedCopier(Socket* socket_from,
Socket* socket_to)
: socket_from_(socket_from),
socket_to_(socket_to),
bytes_read_(0),
write_offset_(0) {
}
bool AddToReadSet(fd_set* read_fds) {
if (bytes_read_ == 0)
return socket_from_->AddFdToSet(read_fds);
return false;
}
bool AddToWriteSet(fd_set* write_fds) {
if (write_offset_ < bytes_read_)
return socket_to_->AddFdToSet(write_fds);
return false;
}
bool TryRead(const fd_set& read_fds) {
if (!socket_from_->IsFdInSet(read_fds))
return false;
if (bytes_read_ != 0) // Can't read.
return false;
int ret = socket_from_->Read(buffer_, kBufferSize);
if (ret > 0) {
bytes_read_ = ret;
return true;
}
return false;
}
bool TryWrite(const fd_set& write_fds) {
if (!socket_to_->IsFdInSet(write_fds))
return false;
if (write_offset_ >= bytes_read_) // Nothing to write.
return false;
int ret = socket_to_->Write(buffer_ + write_offset_,
bytes_read_ - write_offset_);
if (ret > 0) {
write_offset_ += ret;
if (write_offset_ == bytes_read_) {
write_offset_ = 0;
bytes_read_ = 0;
}
return true;
}
return false;
}
private:
// Not owned.
Socket* socket_from_;
Socket* socket_to_;
// A big buffer to let our file-over-http bridge work more like real file.
static const int kBufferSize = 1024 * 128;
int bytes_read_;
int write_offset_;
char buffer_[kBufferSize];
DISALLOW_COPY_AND_ASSIGN(BufferedCopier);
};
} // namespace
Forwarder::Forwarder(scoped_ptr<Socket> socket1, scoped_ptr<Socket> socket2)
: socket1_(socket1.Pass()),
socket2_(socket2.Pass()) {
DCHECK(socket1_.get());
DCHECK(socket2_.get());
// The forwarder thread doesn't need to listen to notifications. It can be
// keept alive until either the conenction is broken or the program exit.
socket1_->reset_exit_notifier_fd();
socket2_->reset_exit_notifier_fd();
}
Forwarder::~Forwarder() {
socket1_->Close();
socket2_->Close();
}
void Forwarder::Run() {
const int nfds = Socket::GetHighestFileDescriptor(*socket1_, *socket2_) + 1;
fd_set read_fds;
fd_set write_fds;
// Copy from socket1 to socket2
BufferedCopier buffer1(socket1_.get(), socket2_.get());
// Copy from socket2 to socket1
BufferedCopier buffer2(socket2_.get(), socket1_.get());
bool run = true;
while (run) {
FD_ZERO(&read_fds);
FD_ZERO(&write_fds);
buffer1.AddToReadSet(&read_fds);
buffer2.AddToReadSet(&read_fds);
buffer1.AddToWriteSet(&write_fds);
buffer2.AddToWriteSet(&write_fds);
if (HANDLE_EINTR(select(nfds, &read_fds, &write_fds, NULL, NULL)) <= 0) {
LOG(ERROR) << "Select error: " << safe_strerror(errno);
break;
}
// When a socket in the read set closes the connection, select() returns
// with that socket descriptor set as "ready to read". When we call
// TryRead() below, it will return false, but the while loop will continue
// to run until all the write operations are finished, to make sure the
// buffers are completely flushed out.
// Keep running while we have some operation to do.
run = buffer1.TryRead(read_fds);
run = run || buffer2.TryRead(read_fds);
run = run || buffer1.TryWrite(write_fds);
run = run || buffer2.TryWrite(write_fds);
}
delete this;
}
void Forwarder::Join() {
NOTREACHED() << "Can't Join a Forwarder thread.";
}
} // namespace forwarder
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