void Subprocess::communicate(FdCallback readCallback,
FdCallback writeCallback) {
returnCode_.enforce(ProcessReturnCode::RUNNING);
setAllNonBlocking();
std::vector<pollfd> fds;
fds.reserve(pipes_.size());
std::vector<int> toClose;
toClose.reserve(pipes_.size());
while (!pipes_.empty()) {
fds.clear();
toClose.clear();
for (auto& p : pipes_) {
pollfd pfd;
pfd.fd = p.parentFd;
// Yes, backwards, PIPE_IN / PIPE_OUT are defined from the
// child's point of view.
if (!p.enabled) {
// Still keeping fd in watched set so we get notified of POLLHUP /
// POLLERR
pfd.events = 0;
} else if (p.direction == PIPE_IN) {
pfd.events = POLLOUT;
} else {
pfd.events = POLLIN;
}
fds.push_back(pfd);
}
int r;
do {
r = ::poll(fds.data(), fds.size(), -1);
} while (r == -1 && errno == EINTR);
checkUnixError(r, "poll");
for (int i = 0; i < pipes_.size(); ++i) {
auto& p = pipes_[i];
DCHECK_EQ(fds[i].fd, p.parentFd);
short events = fds[i].revents;
bool closed = false;
if (events & POLLOUT) {
DCHECK(!(events & POLLIN));
if (writeCallback(p.parentFd, p.childFd)) {
toClose.push_back(i);
closed = true;
}
}
if (events & POLLIN) {
DCHECK(!(events & POLLOUT));
if (readCallback(p.parentFd, p.childFd)) {
toClose.push_back(i);
closed = true;
}
}
if ((events & (POLLHUP | POLLERR)) && !closed) {
toClose.push_back(i);
closed = true;
}
}
// Close the fds in reverse order so the indexes hold after erase()
for (int idx : boost::adaptors::reverse(toClose)) {
auto pos = pipes_.begin() + idx;
closeChecked(pos->parentFd);
pipes_.erase(pos);
}
}
}
void Subprocess::communicate(FdCallback readCallback,
FdCallback writeCallback) {
// This serves to prevent wait() followed by communicate(), but if you
// legitimately need that, send a patch to delete this line.
returnCode_.enforce(ProcessReturnCode::RUNNING);
setAllNonBlocking();
std::vector<pollfd> fds;
fds.reserve(pipes_.size());
std::vector<size_t> toClose; // indexes into pipes_
toClose.reserve(pipes_.size());
while (!pipes_.empty()) {
fds.clear();
toClose.clear();
for (auto& p : pipes_) {
pollfd pfd;
pfd.fd = p.pipe.fd();
// Yes, backwards, PIPE_IN / PIPE_OUT are defined from the
// child's point of view.
if (!p.enabled) {
// Still keeping fd in watched set so we get notified of POLLHUP /
// POLLERR
pfd.events = 0;
} else if (p.direction == PIPE_IN) {
pfd.events = POLLOUT;
} else {
pfd.events = POLLIN;
}
fds.push_back(pfd);
}
int r;
do {
r = ::poll(fds.data(), fds.size(), -1);
} while (r == -1 && errno == EINTR);
checkUnixError(r, "poll");
for (size_t i = 0; i < pipes_.size(); ++i) {
auto& p = pipes_[i];
auto parentFd = p.pipe.fd();
DCHECK_EQ(fds[i].fd, parentFd);
short events = fds[i].revents;
bool closed = false;
if (events & POLLOUT) {
DCHECK(!(events & POLLIN));
if (writeCallback(parentFd, p.childFd)) {
toClose.push_back(i);
closed = true;
}
}
// Call read callback on POLLHUP, to give it a chance to read (and act
// on) end of file
if (events & (POLLIN | POLLHUP)) {
DCHECK(!(events & POLLOUT));
if (readCallback(parentFd, p.childFd)) {
toClose.push_back(i);
closed = true;
}
}
if ((events & (POLLHUP | POLLERR)) && !closed) {
toClose.push_back(i);
closed = true;
}
}
// Close the fds in reverse order so the indexes hold after erase()
for (int idx : boost::adaptors::reverse(toClose)) {
auto pos = pipes_.begin() + idx;
pos->pipe.close(); // Throws on error
pipes_.erase(pos);
}
}
}