forked from OSchip/llvm-project
85 lines
3.5 KiB
C++
85 lines
3.5 KiB
C++
//===--- Shutdown.h - Unclean exit scenarios --------------------*- C++ -*-===//
|
|
//
|
|
// 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// LSP specifies a protocol for shutting down: a `shutdown` request followed
|
|
// by an `exit` notification. If this protocol is followed, clangd should
|
|
// finish outstanding work and exit with code 0.
|
|
//
|
|
// The way this works in the happy case:
|
|
// - when ClangdLSPServer gets `shutdown`, it sets a flag
|
|
// - when ClangdLSPServer gets `exit`, it returns false to indicate end-of-LSP
|
|
// - Transport::loop() returns with no error
|
|
// - ClangdServer::run() checks the shutdown flag and returns with no error.
|
|
// - we `return 0` from main()
|
|
// - destructor of ClangdServer and other main()-locals runs.
|
|
// This blocks until outstanding requests complete (results are ignored)
|
|
// - global destructors run, such as fallback deletion of temporary files
|
|
//
|
|
// There are a number of things that can go wrong. Some are handled here, and
|
|
// some elsewhere.
|
|
// - `exit` notification with no `shutdown`:
|
|
// ClangdServer::run() sees this and returns false, main() returns nonzero.
|
|
// - stdin/stdout are closed
|
|
// The Transport detects this while doing IO and returns an error from loop()
|
|
// ClangdServer::run() logs a message and then returns false, etc
|
|
// - a request thread gets stuck, so the ClangdServer destructor hangs.
|
|
// Before returning from main(), we start a watchdog thread to abort() the
|
|
// process if it takes too long to exit. See abortAfterTimeout().
|
|
// - clangd crashes (e.g. segfault or assertion)
|
|
// A fatal signal is sent (SEGV, ABRT, etc)
|
|
// The installed signal handler prints a stack trace and exits.
|
|
// - parent process goes away or tells us to shut down
|
|
// A "graceful shutdown" signal is sent (TERM, HUP, etc).
|
|
// The installed signal handler calls requestShutdown() which sets a flag.
|
|
// The Transport IO is interrupted, and Transport::loop() checks the flag and
|
|
// returns an error, etc.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_SHUTDOWN_H
|
|
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SHUTDOWN_H
|
|
|
|
#include <cerrno>
|
|
#include <chrono>
|
|
|
|
namespace clang {
|
|
namespace clangd {
|
|
|
|
/// Causes this process to crash if still running after Timeout.
|
|
void abortAfterTimeout(std::chrono::seconds Timeout);
|
|
|
|
/// Sets a flag to indicate that clangd was sent a shutdown signal, and the
|
|
/// transport loop should exit at the next opportunity.
|
|
/// If shutdown was already requested, aborts the process.
|
|
/// This function is threadsafe and signal-safe.
|
|
void requestShutdown();
|
|
/// Checks whether requestShutdown() was called.
|
|
/// This function is threadsafe and signal-safe.
|
|
bool shutdownRequested();
|
|
|
|
/// Retry an operation if it gets interrupted by a signal.
|
|
/// This is like llvm::sys::RetryAfterSignal, except that if shutdown was
|
|
/// requested (which interrupts IO), we'll fail rather than retry.
|
|
template <typename Fun, typename Ret = decltype(std::declval<Fun>()())>
|
|
Ret retryAfterSignalUnlessShutdown(
|
|
const typename std::enable_if<true, Ret>::type &Fail, // Suppress deduction.
|
|
const Fun &F) {
|
|
Ret Res;
|
|
do {
|
|
if (shutdownRequested())
|
|
return Fail;
|
|
errno = 0;
|
|
Res = F();
|
|
} while (Res == Fail && errno == EINTR);
|
|
return Res;
|
|
}
|
|
|
|
} // namespace clangd
|
|
} // namespace clang
|
|
|
|
#endif
|