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//===-- MainLoopWindows.cpp -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "lldb/Host/windows/MainLoopWindows.h"
#include "lldb/Host/Config.h"
#include "lldb/Utility/Status.h"
#include "llvm/Config/llvm-config.h"
#include <algorithm>
#include <cassert>
#include <cerrno>
#include <csignal>
#include <ctime>
#include <vector>
#include <winsock2.h>
using namespace lldb;
using namespace lldb_private;
static DWORD ToTimeout(std::optional<MainLoopWindows::TimePoint> point) {
using namespace std::chrono;
if (!point)
return WSA_INFINITE;
nanoseconds dur = (std::max)(*point - steady_clock::now(), nanoseconds(0));
return ceil<milliseconds>(dur).count();
}
MainLoopWindows::MainLoopWindows() {
m_interrupt_event = WSACreateEvent();
assert(m_interrupt_event != WSA_INVALID_EVENT);
}
MainLoopWindows::~MainLoopWindows() {
assert(m_read_fds.empty());
BOOL result = WSACloseEvent(m_interrupt_event);
assert(result == TRUE);
UNUSED_IF_ASSERT_DISABLED(result);
}
llvm::Expected<size_t> MainLoopWindows::Poll() {
std::vector<WSAEVENT> events;
events.reserve(m_read_fds.size() + 1);
for (auto &[fd, info] : m_read_fds) {
int result = WSAEventSelect(fd, info.event, FD_READ | FD_ACCEPT | FD_CLOSE);
assert(result == 0);
UNUSED_IF_ASSERT_DISABLED(result);
events.push_back(info.event);
}
events.push_back(m_interrupt_event);
DWORD result =
WSAWaitForMultipleEvents(events.size(), events.data(), FALSE,
ToTimeout(GetNextWakeupTime()), FALSE);
for (auto &fd : m_read_fds) {
int result = WSAEventSelect(fd.first, WSA_INVALID_EVENT, 0);
assert(result == 0);
UNUSED_IF_ASSERT_DISABLED(result);
}
if (result >= WSA_WAIT_EVENT_0 && result < WSA_WAIT_EVENT_0 + events.size())
return result - WSA_WAIT_EVENT_0;
// A timeout is treated as a (premature) signalization of the interrupt event.
if (result == WSA_WAIT_TIMEOUT)
return events.size() - 1;
return llvm::createStringError(llvm::inconvertibleErrorCode(),
"WSAWaitForMultipleEvents failed");
}
MainLoopWindows::ReadHandleUP
MainLoopWindows::RegisterReadObject(const IOObjectSP &object_sp,
const Callback &callback, Status &error) {
if (!object_sp || !object_sp->IsValid()) {
error = Status::FromErrorString("IO object is not valid.");
return nullptr;
}
if (object_sp->GetFdType() != IOObject::eFDTypeSocket) {
error = Status::FromErrorString(
"MainLoopWindows: non-socket types unsupported on Windows");
return nullptr;
}
WSAEVENT event = WSACreateEvent();
if (event == WSA_INVALID_EVENT) {
error =
Status::FromErrorStringWithFormat("Cannot create monitoring event.");
return nullptr;
}
const bool inserted =
m_read_fds
.try_emplace(object_sp->GetWaitableHandle(), FdInfo{event, callback})
.second;
if (!inserted) {
WSACloseEvent(event);
error = Status::FromErrorStringWithFormat(
"File descriptor %d already monitored.",
object_sp->GetWaitableHandle());
return nullptr;
}
return CreateReadHandle(object_sp);
}
void MainLoopWindows::UnregisterReadObject(IOObject::WaitableHandle handle) {
auto it = m_read_fds.find(handle);
assert(it != m_read_fds.end());
BOOL result = WSACloseEvent(it->second.event);
assert(result == TRUE);
UNUSED_IF_ASSERT_DISABLED(result);
m_read_fds.erase(it);
}
void MainLoopWindows::ProcessReadObject(IOObject::WaitableHandle handle) {
auto it = m_read_fds.find(handle);
if (it != m_read_fds.end())
it->second.callback(*this); // Do the work
}
Status MainLoopWindows::Run() {
m_terminate_request = false;
Status error;
while (!m_terminate_request) {
llvm::Expected<size_t> signaled_event = Poll();
if (!signaled_event)
return Status::FromError(signaled_event.takeError());
if (*signaled_event < m_read_fds.size()) {
auto &KV = *std::next(m_read_fds.begin(), *signaled_event);
WSAResetEvent(KV.second.event);
ProcessReadObject(KV.first);
} else {
assert(*signaled_event == m_read_fds.size());
WSAResetEvent(m_interrupt_event);
}
ProcessCallbacks();
}
return Status();
}
void MainLoopWindows::Interrupt() { WSASetEvent(m_interrupt_event); }
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