From c3272f7d1f4c9a91dd06faab3e0186075603d362 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B6nke=20Ludwig?= <sludwig@rejectedsoftware.com>
Date: Tue, 30 Oct 2018 12:27:01 +0100
Subject: [PATCH] Fix assertion in SpinLock when called from a signal handler.

Since the signal handler can be called in any thread of the application, it may happen so in a non-D thread where Thread.getThis() returns null. This change works around this and also removes the need to call SpinLock.setup on thread startup.
---
 source/vibe/core/core.d | 12 ++++--------
 source/vibe/core/sync.d | 21 ++++++++++-----------
 2 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/source/vibe/core/core.d b/source/vibe/core/core.d
index 81266c2..d7f85e3 100644
--- a/source/vibe/core/core.d
+++ b/source/vibe/core/core.d
@@ -1350,9 +1350,6 @@ shared static this()
 
 	import std.concurrency;
 	scheduler = new VibedScheduler;
-
-	import vibe.core.sync : SpinLock;
-	SpinLock.setup();
 }
 
 shared static ~this()
@@ -1377,10 +1374,6 @@ static this()
 	synchronized (st_threadsMutex)
 		if (!st_threads.any!(c => c.thread is thisthr))
 			st_threads ~= ThreadContext(thisthr);
-
-
-	import vibe.core.sync : SpinLock;
-	SpinLock.setup();
 }
 
 static ~this()
@@ -1463,7 +1456,10 @@ private extern(C) void onSignal(int signal)
 nothrow {
 	logInfo("Received signal %d. Shutting down.", signal);
 	atomicStore(st_term, true);
-	try st_threadsSignal.emit(); catch (Throwable) {}
+	try st_threadsSignal.emit();
+	catch (Throwable th) {
+		logDebug("Failed to notify for event loop exit: %s", th.msg);
+	}
 }
 
 private extern(C) void onBrokenPipe(int signal)
diff --git a/source/vibe/core/sync.d b/source/vibe/core/sync.d
index f84a455..9d1689b 100644
--- a/source/vibe/core/sync.d
+++ b/source/vibe/core/sync.d
@@ -1217,21 +1217,20 @@ package shared(Monitor!(T, M)) createMonitor(T, M)(M mutex)
 
 package struct SpinLock {
 	private shared int locked;
-	static int threadID = 0;
-
-	static void setup()
-	{
-		import core.thread : Thread;
-		threadID = cast(int)cast(void*)Thread.getThis();
-	}
+	debug static int threadID;
 
 	@safe nothrow @nogc shared:
 
 	bool tryLock()
 	@trusted {
-		assert(threadID != 0, "SpinLock.setup() was not called.");
-		assert(atomicLoad(locked) != threadID, "Recursive lock attempt.");
-		return cas(&locked, 0, threadID);
+		debug {
+			import core.thread : Thread;
+			if (threadID == 0) threadID = cast(int)cast(void*)Thread.getThis();
+			if (threadID == 0) threadID = -1; // workaround for non-D threads
+			assert(atomicLoad(locked) != threadID, "Recursive lock attempt.");
+			int tid = threadID;
+		} else int tid = 1;
+		return cas(&locked, 0, tid);
 	}
 
 	void lock()
@@ -1241,7 +1240,7 @@ package struct SpinLock {
 
 	void unlock()
 	@trusted {
-		assert(atomicLoad(locked) == threadID, "Unlocking spin lock that is not owned by the current thread.");
+		debug assert(atomicLoad(locked) == threadID, "Unlocking spin lock that is not owned by the current thread.");
 		atomicStore(locked, 0);
 	}
 }