Debug output: improve output performance and design

- Replace the `outputF` function with the `DebugOutput` object that allows
  to bundle up the outputs and flush them to the debug console only when ready.
- It also improves the testability of debug tools that need to output as you
  now only have to overload the output part of the class.
- `DebugOutput` comes with its set of tests.
- The existing function guards tests have been updated to reflect the new
  output method.

- Future improvements:
  - Instead of an extern variable to the global `DebugOutput` (yuk) we could
    implement a DebugOutput stack where we could push and pop `DebugOutput`
    objects. This stack would live in the application object.

[#8 state:needs_ack responsible:npp-community]

Signed-off-by: Jocelyn Legault <jocelynlegault@gmail.com>

PowerEditor/src/MISC/Debug/npp_debug.cpp

@@ -23,29 +23,57 @@
 
 namespace NppDebug
 {
+DebugOutput defaultDebugOutput;
+DebugOutput* g_debugOutput = &defaultDebugOutput;
 
-static outputFunction debugOutput = OutputDebugString;
+DebugOutput::DebugOutput()
+{
+	resetValues();
+}
+
+void DebugOutput::printf(const TCHAR* format, ...)
+{
+	if (format)
+	{
+		va_list args;
+
+		va_start( args, format );
+		int nbWrittenChar = _vsntprintf_s( m_currentPtr, MAX_DEBUG_STR - m_currentLen, _TRUNCATE, format, args );
+		if (nbWrittenChar >= 0)
+		{
+			m_currentLen += nbWrittenChar;
+		}
+		else // _vsntprintf_s returned -1, this means we were truncated.
+		{
+			m_currentLen = MAX_DEBUG_STR-1;
+		}
+		m_currentPtr = &m_outputStr[0] + m_currentLen;
+	}
+	else
+	{
+		*m_currentPtr = TEXT('\0');
+	}
+}
+
+void DebugOutput::flush()
+{
+	if (m_outputStr[0] != TEXT('\0'))
+	{
+		output(&m_outputStr[0]);
+		resetValues();
+	}
+}
 
-outputFunction setOutputFunction(outputFunction newOutputFunction)
+void DebugOutput::output(const TCHAR* str)
 {
-	outputFunction currentOutputFunc = debugOutput;
-	debugOutput = newOutputFunction;
-	return currentOutputFunc;
+	OutputDebugString(str);
 }
 
-// Joce: We could (should?) make OutputF a functor
-void outputF(TCHAR* format, ...)
+void DebugOutput::resetValues()
 {
-	va_list args;
-	int len;
-	TCHAR* buffer;
-
-	va_start( args, format );
-	len = _vsctprintf( format, args ) + 1; // _vscprintf doesn't count terminating '\0'
-	buffer = new TCHAR[len];
-	_vstprintf_s( buffer, len, format, args );
-	debugOutput(buffer);
-	delete [] buffer;
+	m_outputStr[0] = TEXT('\0');
+	m_currentPtr = &m_outputStr[0];
+	m_currentLen = 0;
 }
 
 int FuncGuard::_depth = 0;
@@ -61,9 +89,10 @@ FuncGuard::FuncGuard( const TCHAR* funcsig, const TCHAR* funcname, const TCHAR*
 		_category = category;
 
 		// JOCE Only one call to OutputF.
-		outputF(TEXT("%s%s(%d):\n"),  getIndent(), file, line);
-		outputF(TEXT("%sEntering[ %s ]\n"),  getIndent(), funcsig);
+		g_debugOutput->printf(TEXT("%s%s(%d):\n"),  getIndent(), file, line);
+		g_debugOutput->printf(TEXT("%sEntering[ %s ]\n"),  getIndent(), funcsig);
 		indent();
+		g_debugOutput->flush();
 	}
 }
 
@@ -72,15 +101,16 @@ FuncGuard::~FuncGuard()
 	if (_state == Enabled)
 	{
 		unindent();
-		outputF(TEXT("%sLeaving[ %s ]\n"), getIndent(), _funcname.c_str());
+		g_debugOutput->printf(TEXT("%sLeaving[ %s ]\n"), getIndent(), _funcname.c_str());
+		g_debugOutput->flush();
 	}
 }
 
 void FuncGuard::outputIndent()
 {
 	if (_state == Enabled)
 	{
-		outputF(getIndent());
+		g_debugOutput->printf(getIndent());
 	}
 }
 

PowerEditor/src/MISC/Debug/npp_debug.h

@@ -20,14 +20,25 @@
 
 #ifndef SHIPPING
 
-#define MAX_DEBUG_INDENT 1024
+#define MAX_DEBUG_INDENT 32
+#define MAX_DEBUG_STR 1024
 namespace NppDebug
 {
-	typedef void (__stdcall *outputFunction)(const TCHAR*);
-
-	outputFunction setOutputFunction(outputFunction newOutputFunction);
+	class DebugOutput
+	{
+	public:
+		DebugOutput();
+		void printf(const TCHAR* format, ...);
+		void flush();
+	protected:
+		virtual void output(const TCHAR* str);
+		void resetValues();
+		TCHAR m_outputStr[MAX_DEBUG_STR];
+		TCHAR* m_currentPtr;
+		int m_currentLen;
+	};
 
-	void outputF(TCHAR* format, ...);
+	extern DebugOutput* g_debugOutput;
 
 	// JOCE: Nice to have: configurable indent character (' ', '\t', '_', '+', etc...)
 	class FuncGuard
@@ -59,7 +70,7 @@ namespace NppDebug
 } // namespace NppDebug
 
 // debugf() works just at printf(), except that it outputs to the debug console in MSVC
-#define debugf(format, ...) NppDebug::outputF(format, __VA_ARGS__)
+#define debugf(format, ...) NppDebug::g_debugOutput->printf(format, __VA_ARGS__); NppDebug::g_debugOutput->flush()
 
 // line_debugf() works just as debugf, but it prefixes the text message with the file name
 // and line number of the call in a way that MSVC recognizes so you can double click on the
@@ -69,9 +80,9 @@ namespace NppDebug
 // source\folder\file.cpp(42): Hello World!!!
 
 #define line_debugf(format, ...) \
-	/* JOCE: modify to make that a single call to OutputF */ \
-	NppDebug::outputF(TEXT("%s(%d): "), TEXT(__FILE__), __LINE__); \
-	NppDebug::outputF(format, __VA_ARGS__)
+	NppDebug::g_debugOutput->printf(TEXT("%s(%d): "), TEXT(__FILE__), __LINE__); \
+	NppDebug::g_debugOutput->printf(format, __VA_ARGS__); \
+	NppDebug::g_debugOutput->flush()
 
 //
 //  Debug Guards
@@ -183,9 +194,9 @@ namespace NppDebug
 // Leaving[ FooTwo ]
 
 #define guard_debugf(format, ...) \
-	/* JOCE: modify to make that a single call to OutputF (should make guard_debugf part of the function guard */ \
 	__npp_func_guard__.outputIndent(); \
-	NppDebug::outputF(format, __VA_ARGS__)
+	NppDebug::g_debugOutput->printf(format, __VA_ARGS__); \
+	NppDebug::g_debugOutput->flush()
 
 #else // if !SHIPPING