logging improvements (#664)

* Eliminate spurious `FlushFileBuffers` calls on Windows by tracking writes
* Make cache log file creation optional

1 files changed, 10 insertions, 0 deletions

diff --git a/src/zenutil/include/zenutil/logging/rotatingfilesink.h b/src/zenutil/include/zenutil/logging/rotatingfilesink.h
index 5c6c655b8..4d10f3794 100644
--- a/src/zenutil/include/zenutil/logging/rotatingfilesink.h
+++ b/src/zenutil/include/zenutil/logging/rotatingfilesink.h
@@ -114,6 +114,11 @@ public:
 	}
 	virtual void flush() override
 	{
+		if (!m_NeedFlush)
+		{
+			return;
+		}
+
 		ZEN_MEMSCOPE(ELLMTag::Logging);
 
 		try
@@ -128,6 +133,8 @@ public:
 		{
 			// Silently eat errors
 		}
+
+		m_NeedFlush = false;
 	}
 
 	virtual void set_pattern(const std::string& pattern) override
@@ -204,6 +211,7 @@ private:
 		{
 			return false;
 		}
+		m_NeedFlush = true;
 		return true;
 	}
 
@@ -229,6 +237,7 @@ private:
 		{
 			return false;
 		}
+		m_NeedFlush = true;
 		return true;
 	}
 
@@ -239,6 +248,7 @@ private:
 	const std::size_t				   m_MaxSize;
 	const std::size_t				   m_MaxFiles;
 	BasicFile						   m_CurrentFile;
+	bool							   m_NeedFlush = false;
 };
 
 }  // namespace zen::logging