From 0e4d503384a254c843a065c26f77bc19dfccff16 Mon Sep 17 00:00:00 2001
From: Justin Berger <j.david.berger@gmail.com>
Date: Sat, 22 Jul 2017 09:29:18 -0600
Subject: server: Added thread check to protect writedata

---
 Source/cmConnection.cxx | 6 ++++++
 Source/cmServer.cxx     | 6 ++++++
 Source/cmServer.h       | 9 +++++++++
 3 files changed, 21 insertions(+)

diff --git a/Source/cmConnection.cxx b/Source/cmConnection.cxx
index c0d1b82..f482412 100644
--- a/Source/cmConnection.cxx
+++ b/Source/cmConnection.cxx
@@ -69,6 +69,12 @@ bool cmEventBasedConnection::IsOpen() const
 
 void cmEventBasedConnection::WriteData(const std::string& _data)
 {
+#ifndef NDEBUG
+  auto curr_thread_id = uv_thread_self();
+  assert(this->Server);
+  assert(uv_thread_equal(&curr_thread_id, &this->Server->ServeThreadId));
+#endif
+
   auto data = _data;
   assert(this->WriteStream);
   if (BufferStrategy) {
diff --git a/Source/cmServer.cxx b/Source/cmServer.cxx
index b1b4020..30d0f51 100644
--- a/Source/cmServer.cxx
+++ b/Source/cmServer.cxx
@@ -436,6 +436,12 @@ bool cmServerBase::StartServeThread()
 
 bool cmServerBase::Serve(std::string* errorMessage)
 {
+#ifndef NDEBUG
+  uv_thread_t blank_thread_t = {};
+  assert(uv_thread_equal(&blank_thread_t, &ServeThreadId));
+  ServeThreadId = uv_thread_self();
+#endif
+
   errorMessage->clear();
 
   uv_signal_init(&Loop, &this->SIGINTHandler);
diff --git a/Source/cmServer.h b/Source/cmServer.h
index d8f73c1..15fd2ba 100644
--- a/Source/cmServer.h
+++ b/Source/cmServer.h
@@ -67,6 +67,15 @@ protected:
   bool ServeThreadRunning = false;
   uv_thread_t ServeThread;
   uv_async_t ShutdownSignal;
+#ifndef NDEBUG
+public:
+  // When the server starts it will mark down it's current thread ID,
+  // which is useful in other contexts to just assert that operations
+  // are performed on that same thread.
+  uv_thread_t ServeThreadId = {};
+
+protected:
+#endif
 
   uv_loop_t Loop;
 
-- 
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