Major overhaul of DebugPrint

Source/Integration/engineutil.hpp

@@ -1,24 +1,119 @@
 #pragma once
 
-#include "enginewrapper.hpp"
+//////////////////////////////////////////////////////////////
+//
+// Namespace DebugPrint
+//
+// This namespace contains the function "DPrint",
+// which is short for debugging print.  This
+// is what you should use if you want to print
+// a debugging message.
+//
+// Messages printed using "DPrint" will
+// be routed to several destinations.  These
+// might include a logfile, the unreal console,
+// and the visual studio debugging log.
+//
+// In order for "DPrint" to work, you have to
+// configure them once, at program initialization
+// time.  This is done using the functions in
+// namespace DebugPrintConfig, below.
+//
+// We promise that namespace DebugPrint will
+// only ever contain one function, 'DPrint.'
+// that way, it's safe for you to put
+// 'using namespace DebugPrint' in your code.
+//
+// All DPrint-related functionality is
+// thread-safe.  A single 'DPrint' is meant to
+// be output atomically.
+//
+// It is fine for the content of the DPrint
+// string to contain newlines.
+// 
+//////////////////////////////////////////////////////////////
 
-namespace engineutil {
-// Load the DLL and initialize the wrapper, if possible.
-void init_wrapper(EngineWrapper* w);
+namespace DebugPrint {
+	// Print text into the debug log.
+	void DPrint(const FString& fs);
 
-// Print text on the console.
-void DPrint(const FString& fs);
+	// Print text into the debug log.
+	void DPrint(const char* msg);
 
-// Print text on the console.
-void DPrint(const char* msg);
+	// Print text into the debug log.
+	void DPrint(const char* msg, size_t len);
+};
 
-// Print text on the console.
-void DPrintHook(const char* msg, size_t len);
+//////////////////////////////////////////////////////////////
+//
+// namespace DebugPrintControl
+//
+// This namespace contains the functions
+// necessary to initialize "DPrint", and
+// route its output to several destinations.
+//
+// "DPrint" is a callback-based design.
+// Initialization might consist of: register a
+// callback that sends a string to a logfile,
+// register another callback that sends a string
+// to visual studio's debug console, and register
+// a third one that sends a string to the
+// unreal console. Each time somebody calls
+// 'DPrint', all three callbacks will get invoked.
+// 
+// There is also a 'collect' option where you
+// can ask "DPrint" to save the messages in a
+// buffer, which you can then collect at
+// your leisure.  You can use buffering and
+// callbacks at the same time.  Note that
+// buffering is inherently less than ideal for
+// messages that warn of imminent program aborts.
+// So it is recommended that you use at least one
+// callback that sends its output without delay.
+//
+//////////////////////////////////////////////////////////////
 
-// Get all the stored dprints.
-TArray<FString> DPrintGetStored();
+namespace DebugPrintControl {
+	// The prototype for a callback function.
+	//
+	using DPrintCallback = void (*)(const FString& fs);
 
-class ConsoleOutput {
+	// Register a callback.
+	//
+	// Registering a callback that is already
+	// registered is a no-op.
+	//
+	void RegisterCallback(DPrintCallback f);
+
+	// Enable collection in a buffer.
+	//
+	// If collection is already enabled, this is a no-op.
+	//
+	void EnableCollection();
+
+	// Collect all the stored messages, and clear the storage.
+	//
+	TArray<FString> GetStored();
+};
+
+//////////////////////////////////////////////////////////////
+//
+// ConsoleOutput
+//
+// This class stores the text that's in the unreal console.
+// It stores it as one great big string, which contains
+// newlines to denote line breaks.
+//
+// This class also contains a 'dirty' bit.  Each time somebody
+// appends a line of text to the console, the dirty bit is
+// automatically set.  The bit can be checked using 'IsDirty'
+// and cleared using 'ClearDirty'.  This makes it so that
+// you don't have to update the unreal widget unless the
+// text has actually changed.
+//
+//////////////////////////////////////////////////////////////
+
+class FConsoleOutput {
 private:
 	FString Content;
 	bool Dirty;
@@ -44,5 +139,3 @@ public:
 };
 
 
-} // namespace engineutil
-