event/Loop: set thread to current thread by default

Allows eliminating lots of complexity and workarounds for bogus
assertion failures.

src/db/update/Service.cxx

@@ -62,7 +62,7 @@ UpdateService::~UpdateService()
 void
 UpdateService::CancelAllAsync()
 {
-	assert(GetEventLoop().IsInsideOrNull());
+	assert(GetEventLoop().IsInside());
 
 	queue.Clear();
 
@@ -144,7 +144,7 @@ UpdateService::Task()
 void
 UpdateService::StartThread(UpdateQueueItem &&i)
 {
-	assert(GetEventLoop().IsInsideOrNull());
+	assert(GetEventLoop().IsInside());
 	assert(walk == nullptr);
 
 	modified = false;
@@ -170,7 +170,7 @@ UpdateService::GenerateId()
 unsigned
 UpdateService::Enqueue(const char *path, bool discard)
 {
-	assert(GetEventLoop().IsInsideOrNull());
+	assert(GetEventLoop().IsInside());
 
 	/* determine which (mounted) database will be updated and what
 	   storage will be scanned */

src/event/Call.cxx

@@ -79,7 +79,7 @@ private:
 void
 BlockingCall(EventLoop &loop, std::function<void()> &&f)
 {
-	if (loop.IsInsideOrNull()) {
+	if (loop.IsInside()) {
 		/* we're already inside the loop - we can simply call
 		   the function */
 		f();

src/event/IdleMonitor.cxx

@@ -26,7 +26,7 @@
 void
 IdleMonitor::Cancel()
 {
-	assert(loop.IsInsideOrNull());
+	assert(loop.IsInside());
 
 	if (!IsActive())
 		return;
@@ -38,7 +38,7 @@ IdleMonitor::Cancel()
 void
 IdleMonitor::Schedule()
 {
-	assert(loop.IsInsideOrVirgin());
+	assert(loop.IsInside());
 
 	if (IsActive())
 		/* already scheduled */

src/event/Loop.cxx

@@ -27,8 +27,8 @@
 
 #include <algorithm>
 
-EventLoop::EventLoop()
-	:SocketMonitor(*this)
+EventLoop::EventLoop(ThreadId _thread)
+	:SocketMonitor(*this), thread(_thread)
 {
 	SocketMonitor::Open(SocketDescriptor(wake_fd.Get()));
 }
@@ -52,7 +52,7 @@ EventLoop::Break()
 bool
 EventLoop::Abandon(int _fd, SocketMonitor &m)
 {
-	assert(IsInsideOrVirgin());
+	assert(IsInside());
 
 	poll_result.Clear(&m);
 	return poll_group.Abandon(_fd);
@@ -61,7 +61,7 @@ EventLoop::Abandon(int _fd, SocketMonitor &m)
 bool
 EventLoop::RemoveFD(int _fd, SocketMonitor &m)
 {
-	assert(IsInsideOrNull());
+	assert(IsInside());
 
 	poll_result.Clear(&m);
 	return poll_group.Remove(_fd);
@@ -70,7 +70,7 @@ EventLoop::RemoveFD(int _fd, SocketMonitor &m)
 void
 EventLoop::AddIdle(IdleMonitor &i)
 {
-	assert(IsInsideOrVirgin());
+	assert(IsInside());
 	assert(std::find(idle.begin(), idle.end(), &i) == idle.end());
 
 	idle.push_back(&i);
@@ -80,7 +80,7 @@ EventLoop::AddIdle(IdleMonitor &i)
 void
 EventLoop::RemoveIdle(IdleMonitor &i)
 {
-	assert(IsInsideOrVirgin());
+	assert(IsInside());
 
 	auto it = std::find(idle.begin(), idle.end(), &i);
 	assert(it != idle.end());
@@ -91,9 +91,7 @@ EventLoop::RemoveIdle(IdleMonitor &i)
 void
 EventLoop::AddTimer(TimeoutMonitor &t, std::chrono::steady_clock::duration d)
 {
-	/* can't use IsInsideOrVirgin() here because libavahi-client
-	   modifies the timeout during avahi_client_free() */
-	assert(IsInsideOrNull());
+	assert(IsInside());
 
 	timers.insert(TimerRecord(t, now + d));
 	again = true;
@@ -102,7 +100,7 @@ EventLoop::AddTimer(TimeoutMonitor &t, std::chrono::steady_clock::duration d)
 void
 EventLoop::CancelTimer(TimeoutMonitor &t)
 {
-	assert(IsInsideOrNull());
+	assert(IsInside());
 
 	for (auto i = timers.begin(), end = timers.end(); i != end; ++i) {
 		if (&i->timer == &t) {
@@ -128,15 +126,10 @@ ExportTimeoutMS(std::chrono::steady_clock::duration timeout)
 void
 EventLoop::Run()
 {
-	assert(thread.IsNull());
-	assert(virgin);
-
-#ifndef NDEBUG
-	virgin = false;
-#endif
-
-	thread = ThreadId::GetCurrent();
+	if (thread.IsNull())
+		thread = ThreadId::GetCurrent();
 
+	assert(IsInside());
 	assert(!quit);
 	assert(busy);
 
@@ -226,8 +219,6 @@ EventLoop::Run()
 	assert(busy);
 	assert(thread.IsInside());
 #endif
-
-	thread = ThreadId::Null();
 }
 
 void

src/event/Loop.hxx

@@ -98,14 +98,6 @@ class EventLoop final : SocketMonitor
 	 */
 	bool busy = true;
 
-#ifndef NDEBUG
-	/**
-	 * True if Run() was never called.  This is used for assert()
-	 * calls.
-	 */
-	bool virgin = true;
-#endif
-
 	PollGroup poll_group;
 	PollResult poll_result;
 
@@ -115,7 +107,9 @@ class EventLoop final : SocketMonitor
 	ThreadId thread = ThreadId::Null();
 
 public:
-	EventLoop();
+	explicit EventLoop(ThreadId _thread);
+	EventLoop():EventLoop(ThreadId::GetCurrent()) {}
+
 	~EventLoop();
 
 	/**
@@ -135,7 +129,7 @@ public:
 	void Break();
 
 	bool AddFD(int _fd, unsigned flags, SocketMonitor &m) {
-		assert(thread.IsNull() || thread.IsInside());
+		assert(IsInside());
 
 		return poll_group.Add(_fd, flags, &m);
 	}
@@ -200,28 +194,8 @@ public:
 	 */
 	gcc_pure
 	bool IsInside() const noexcept {
-		assert(!thread.IsNull());
-
 		return thread.IsInside();
 	}
-
-#ifndef NDEBUG
-	gcc_pure
-	bool IsInsideOrVirgin() const noexcept {
-		return virgin || IsInside();
-	}
-#endif
-
-	/**
-	 * Like IsInside(), but also returns true if the thread has
-	 * already ended (or was not started yet).  This is useful for
-	 * code which may run during startup or shutdown, when events
-	 * are not yet/anymore handled.
-	 */
-	gcc_pure
-	bool IsInsideOrNull() const noexcept {
-		return thread.IsNull() || thread.IsInside();
-	}
 };
 
 #endif /* MAIN_NOTIFY_H */

src/event/MultiSocketMonitor.cxx

@@ -34,7 +34,7 @@ MultiSocketMonitor::MultiSocketMonitor(EventLoop &_loop)
 void
 MultiSocketMonitor::Reset()
 {
-	assert(GetEventLoop().IsInsideOrNull());
+	assert(GetEventLoop().IsInside());
 
 	fds.clear();
 	IdleMonitor::Cancel();
@@ -45,7 +45,7 @@ MultiSocketMonitor::Reset()
 void
 MultiSocketMonitor::ClearSocketList()
 {
-	assert(GetEventLoop().IsInsideOrNull());
+	assert(GetEventLoop().IsInside());
 
 	fds.clear();
 }

src/event/Thread.hxx

@@ -34,7 +34,7 @@ class EventThread final {
 
 public:
 	EventThread()
-		:thread(BIND_THIS_METHOD(Run)) {}
+		:event_loop(ThreadId::Null()), thread(BIND_THIS_METHOD(Run)) {}
 
 	~EventThread() {
 		Stop();