Cache evt formatters

userspace/libsinsp/eventformatter.cpp

@@ -270,3 +270,26 @@ bool sinsp_evt_formatter::tostring(sinsp_evt* evt, OUT string* res)
 	return false;
 }
 #endif // HAS_FILTERING
+
+sinsp_evt_formatter_cache::sinsp_evt_formatter_cache(sinsp *inspector)
+	: m_inspector(inspector)
+{
+}
+
+sinsp_evt_formatter_cache::~sinsp_evt_formatter_cache()
+{
+}
+
+bool sinsp_evt_formatter_cache::tostring(sinsp_evt *evt, string &format, OUT string *res)
+{
+	auto it = m_formatter_cache.lower_bound(format);
+
+	if(it == m_formatter_cache.end() ||
+	   it->first != format)
+	{
+		it = m_formatter_cache.emplace_hint(it,
+						    std::make_pair(format, make_shared<sinsp_evt_formatter>(m_inspector, format)));
+	}
+
+	return it->second->tostring(evt, res);
+}

userspace/libsinsp/eventformatter.h

@@ -36,11 +36,11 @@ class SINSP_PUBLIC sinsp_evt_formatter
 	/*!
 	  \brief Constructs a formatter.
 
-	  \param inspector Pointer to the inspector instance that will generate the 
+	  \param inspector Pointer to the inspector instance that will generate the
 	   events to be formatter.
 	  \param fmt The printf-like format to use. The accepted format is the same
-	   as the one of the sysdig '-p' command line flag, so refer to the sysdig 
-	   manual for details. 
+	   as the one of the sysdig '-p' command line flag, so refer to the sysdig
+	   manual for details.
 	*/
 	sinsp_evt_formatter(sinsp* inspector, const string& fmt);
 
@@ -50,16 +50,16 @@ class SINSP_PUBLIC sinsp_evt_formatter
 	  \brief Fills res with the string rendering of the event.
 
 	  \param evt Pointer to the event to be converted into string.
-	  \param res Pointer to the string that will be filled with the result. 
+	  \param res Pointer to the string that will be filled with the result.
 
-	  \return true if the string should be shown (based on the initial *), 
+	  \return true if the string should be shown (based on the initial *),
 	   false otherwise.
 	*/
 	bool tostring(sinsp_evt* evt, OUT string* res);
 
 	/*!
 	  \brief Fills res with end of capture string rendering of the event.
-	  \param res Pointer to the string that will be filled with the result. 
+	  \param res Pointer to the string that will be filled with the result.
 
 	  \return true if there is a string to show (based on the format),
 	   false otherwise.
@@ -80,4 +80,25 @@ class SINSP_PUBLIC sinsp_evt_formatter
 	Json::FastWriter m_writer;
 };
 
+/*!
+  \brief Caching version of sinsp_evt_formatter
+  This class is a wrapper around sinsp_evt_formatter, maintaining a
+  cache of previously seen formatters. It avoids the overhead of
+  recreating sinsp_evt_formatter objects for each event.
+*/
+class SINSP_PUBLIC sinsp_evt_formatter_cache
+{
+public:
+	sinsp_evt_formatter_cache(sinsp *inspector);
+	virtual ~sinsp_evt_formatter_cache();
+
+	// Fills in res with the event formatted according to
+	// format. Creates a new sinsp_evt_formatter object if
+	// necessary.
+	bool tostring(sinsp_evt *evt, std::string &format, OUT std::string *res);
+
+private:
+	std::map<std::string,std::shared_ptr<sinsp_evt_formatter>> m_formatter_cache;
+	sinsp *m_inspector;
+};
 /*@}*/