mgorny created this revision.
mgorny added reviewers: labath, krytarowski, emaste, jingham.
Herald added a subscriber: arichardson.
Herald added a project: All.
mgorny requested review of this revision.
Support adding a "pending callback" to the main loop, that will be
called once after all the pending events are processed. This can be
e.g. to defer destroying the process instance until its exit is fully
processed, as suggested in D127500 <https://reviews.llvm.org/D127500>.
Sponsored by: The FreeBSD Foundation
https://reviews.llvm.org/D128253
Files:
lldb/include/lldb/Host/MainLoop.h
lldb/include/lldb/Host/MainLoopBase.h
lldb/source/Host/common/MainLoop.cpp
lldb/unittests/Host/MainLoopTest.cpp
Index: lldb/unittests/Host/MainLoopTest.cpp
===================================================================
--- lldb/unittests/Host/MainLoopTest.cpp
+++ lldb/unittests/Host/MainLoopTest.cpp
@@ -98,6 +98,56 @@
ASSERT_EQ(1u, callback_count);
}
+TEST_F(MainLoopTest, PendingCallback) {
+ char X = 'X';
+ size_t len = sizeof(X);
+ ASSERT_TRUE(socketpair[0]->Write(&X, len).Success());
+
+ MainLoop loop;
+ Status error;
+ auto handle = loop.RegisterReadObject(
+ socketpair[1],
+ [&](MainLoopBase &loop) {
+ // Both callbacks should be called before the loop terminates.
+ loop.AddPendingCallback(make_callback());
+ loop.AddPendingCallback(make_callback());
+ loop.RequestTermination();
+ },
+ error);
+ ASSERT_TRUE(error.Success());
+ ASSERT_TRUE(handle);
+ ASSERT_TRUE(loop.Run().Success());
+ ASSERT_EQ(2u, callback_count);
+}
+
+TEST_F(MainLoopTest, PendingCallbackCalledOnlyOnce) {
+ char X = 'X';
+ size_t len = sizeof(X);
+ ASSERT_TRUE(socketpair[0]->Write(&X, len).Success());
+
+ MainLoop loop;
+ Status error;
+ auto handle = loop.RegisterReadObject(
+ socketpair[1],
+ [&](MainLoopBase &loop) {
+ // Add one pending callback on the first iteration.
+ if (callback_count == 0) {
+ loop.AddPendingCallback([&](MainLoopBase &loop) {
+ callback_count++;
+ });
+ }
+ // Terminate the loop on second iteration.
+ if (callback_count++ >= 1)
+ loop.RequestTermination();
+ },
+ error);
+ ASSERT_TRUE(error.Success());
+ ASSERT_TRUE(handle);
+ ASSERT_TRUE(loop.Run().Success());
+ // 2 iterations of read callback + 1 call of pending callback.
+ ASSERT_EQ(3u, callback_count);
+}
+
#ifdef LLVM_ON_UNIX
TEST_F(MainLoopTest, DetectsEOF) {
Index: lldb/source/Host/common/MainLoop.cpp
===================================================================
--- lldb/source/Host/common/MainLoop.cpp
+++ lldb/source/Host/common/MainLoop.cpp
@@ -347,6 +347,10 @@
#endif
}
+void MainLoop::AddPendingCallback(const Callback &callback) {
+ m_pending_callbacks.push_back(callback);
+}
+
void MainLoop::UnregisterReadObject(IOObject::WaitableHandle handle) {
bool erased = m_read_fds.erase(handle);
UNUSED_IF_ASSERT_DISABLED(erased);
@@ -401,6 +405,10 @@
return error;
impl.ProcessEvents();
+
+ for (const Callback &callback : m_pending_callbacks)
+ callback(*this);
+ m_pending_callbacks.clear();
}
return Status();
}
Index: lldb/include/lldb/Host/MainLoopBase.h
===================================================================
--- lldb/include/lldb/Host/MainLoopBase.h
+++ lldb/include/lldb/Host/MainLoopBase.h
@@ -46,6 +46,13 @@
llvm_unreachable("Not implemented");
}
+ // Add a pending callback that will be executed once after all the pending
+ // events are processed. The callback will be executed even if termination
+ // was requested.
+ virtual void AddPendingCallback(const Callback &callback) {
+ llvm_unreachable("Not implemented");
+ }
+
// Waits for registered events and invoke the proper callbacks. Returns when
// all callbacks deregister themselves or when someone requests termination.
virtual Status Run() { llvm_unreachable("Not implemented"); }
Index: lldb/include/lldb/Host/MainLoop.h
===================================================================
--- lldb/include/lldb/Host/MainLoop.h
+++ lldb/include/lldb/Host/MainLoop.h
@@ -14,6 +14,7 @@
#include "llvm/ADT/DenseMap.h"
#include <csignal>
#include <list>
+#include <vector>
#if !HAVE_PPOLL && !HAVE_SYS_EVENT_H && !defined(__ANDROID__)
#define SIGNAL_POLLING_UNSUPPORTED 1
@@ -59,6 +60,11 @@
SignalHandleUP RegisterSignal(int signo, const Callback &callback,
Status &error);
+ // Add a pending callback that will be executed once after all the pending
+ // events are processed. The callback will be executed even if termination
+ // was requested.
+ void AddPendingCallback(const Callback &callback) override;
+
Status Run() override;
// This should only be performed from a callback. Do not attempt to terminate
@@ -104,6 +110,7 @@
llvm::DenseMap<IOObject::WaitableHandle, Callback> m_read_fds;
llvm::DenseMap<int, SignalInfo> m_signals;
+ std::vector<Callback> m_pending_callbacks;
#if HAVE_SYS_EVENT_H
int m_kqueue;
#endif
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