Added ProcessMonitor class, which is used to monitor a number of sponsor processes, to control Zen instance lifetime

2 files changed, 101 insertions, 1 deletions

diff --git a/zencore/include/zencore/thread.h b/zencore/include/zencore/thread.h
index b18da6031..0e34d6518 100644
--- a/zencore/include/zencore/thread.h
+++ b/zencore/include/zencore/thread.h
@@ -8,6 +8,8 @@
 #	include <shared_mutex>
 #endif
 
+#include <vector>
+
 namespace zen {
 
 /**
@@ -93,6 +95,7 @@ public:
 	ZENCORE_API void Set();
 	ZENCORE_API void Reset();
 	ZENCORE_API bool Wait(int TimeoutMs = -1);
+	ZENCORE_API void Close();
 
 protected:
 	explicit Event(void* EventHandle) : m_EventHandle(EventHandle) {}
@@ -125,7 +128,7 @@ private:
 };
 
 /** Basic process abstraction
- */
+  */
 class ProcessHandle
 {
 public:
@@ -150,6 +153,28 @@ private:
 	int	  m_Pid			  = 0;
 };
 
+/** Process monitor - monitors a list of running processes via polling
+
+    Intended to be used to monitor a set of "sponsor" processes, where
+	we need to determine when none of them remain alive
+
+ */
+
+class ProcessMonitor
+{
+public:
+	ProcessMonitor();
+	~ProcessMonitor();
+
+	ZENCORE_API bool IsRunning();
+	ZENCORE_API void AddPid(int Pid);
+	ZENCORE_API bool IsActive() const;
+
+private:
+	mutable RwLock	   m_Lock;
+	std::vector<void*> m_ProcessHandles;
+};
+
 ZENCORE_API bool IsProcessRunning(int pid);
 ZENCORE_API int	 GetCurrentProcessId();
 
diff --git a/zencore/thread.cpp b/zencore/thread.cpp
index 598466bb4..ee00d38d4 100644
--- a/zencore/thread.cpp
+++ b/zencore/thread.cpp
@@ -76,6 +76,13 @@ Event::Reset()
 	ResetEvent(m_EventHandle);
 }
 
+void 
+Event::Close()
+{
+	CloseHandle(m_EventHandle);
+	m_EventHandle = nullptr;
+}
+
 bool
 Event::Wait(int TimeoutMs)
 {
@@ -168,6 +175,7 @@ ProcessHandle::Initialize(void* ProcessHandle)
 	ZEN_ASSERT(m_ProcessHandle == nullptr);
 	// TODO: perform some debug verification here to verify it's a valid handle?
 	m_ProcessHandle = ProcessHandle;
+	m_Pid			= GetProcessId(m_ProcessHandle);
 }
 
 ProcessHandle::~ProcessHandle()
@@ -255,6 +263,73 @@ ProcessHandle::Wait(int TimeoutMs)
 	return false;
 }
 
+//////////////////////////////////////////////////////////////////////////
+
+ProcessMonitor::ProcessMonitor()
+{
+}
+
+ProcessMonitor::~ProcessMonitor()
+{
+	RwLock::ExclusiveLockScope _(m_Lock);
+
+	for (HANDLE& Proc : m_ProcessHandles)
+	{
+		CloseHandle(Proc);
+		Proc = 0;
+	}
+}
+
+bool
+ProcessMonitor::IsRunning()
+{
+	RwLock::ExclusiveLockScope _(m_Lock);
+
+	bool FoundOne = false;
+
+	for (HANDLE& Proc : m_ProcessHandles)
+	{
+		DWORD ExitCode = 0;
+		GetExitCodeProcess(Proc, &ExitCode);
+		
+		if (ExitCode != STILL_ACTIVE)
+		{
+			CloseHandle(Proc);
+			Proc = 0;
+		}
+		else
+		{
+			// Still alive
+			FoundOne = true;
+		}
+	}
+
+	std::erase_if(m_ProcessHandles, [](HANDLE Handle) { return Handle == 0; });
+
+	return FoundOne;
+}
+
+void
+ProcessMonitor::AddPid(int Pid)
+{
+	HANDLE ProcessHandle = OpenProcess(PROCESS_QUERY_INFORMATION | SYNCHRONIZE, FALSE, Pid);
+
+	if (ProcessHandle)
+	{
+		RwLock::ExclusiveLockScope _(m_Lock);
+		m_ProcessHandles.push_back(ProcessHandle);
+	}
+}
+
+bool
+ProcessMonitor::IsActive() const
+{
+	RwLock::SharedLockScope _(m_Lock);
+	return m_ProcessHandles.empty() == false;
+}
+
+//////////////////////////////////////////////////////////////////////////
+
 bool
 IsProcessRunning(int pid)
 {