integration/Source/Integration/BlueprintErrors.h

//
// BlueprintErrors: Better error handling for blueprint errors.
//

#pragma once

#include "Containers/Array.h"
#include "CoreMinimal.h"
#include "HAL/Platform.h"
#include "Misc/OutputDeviceError.h"
#include "UObject/NameTypes.h"
#include "UObject/ObjectMacros.h"
#include "UObject/UObjectGlobals.h"

#include "BlueprintErrors.generated.h"

/* 
 * enum class ElxLogVerbosity, below, contains all the same error severity levels
 * as ELogVerbosity, but in a form that the blueprint editor can manipulate.
 *
 * We deliberately moved 'Fatal' to the end of the list, and made 'Error' option 0.
 * We did that because we want the editor to default to 'Error' in most cases.
 * Unfortunately, that means the numeric values of the two enums don't match up,
 * so we will need a conversion function.
 * 
 */


/** Log Verbosity: The importance of an error message, which affects which logs the error
 *  message gets written to, and how that message gets filtered.
 * 
 */
UENUM(BlueprintType)
enum class ElxLogVerbosity : uint8 {

	/* Prints an error to the console and log file. The editor collects and reports errors. */
	Error,

	/* Prints a warning to the console and log file. The editor collects and report warnings. */
	Warning,

	/* Prints a message to the console and log file. */
	Display,

	/* Prints a message to the log file, however, it does not print to the console. */
	Log,

	/* Prints a message to a log file only if Verbose logging is enabled for the given category. This is usually used for detailed logging. */
	Verbose,

	/* Prints a message to a log file. If VeryVerbose logging is enabled, then this is used for detailed logging that would otherwise spam output. */
	VeryVerbose,

	/* Danger! Prints a fatal error to the console and log file, then crashes (this crashes the editor too). */
	Fatal,
};


/** Display Duration: How long to display an error message in the game's viewport.
 *
 */
UENUM(BlueprintType)
enum class ElxErrorDisplayDuration : uint8 {

	/* Do not display the message in the viewport */
	No_Show  = 0,

	/* Display the message in the viewport for 1 seconds */
	Show_1_Seconds  = 1,

	/* Display the message in the viewport for 2 seconds */
	Show_2_Seconds  = 2,

	/* Display the message in the viewport for 3 seconds */
	Show_3_Seconds  = 3,

	/* Display the message in the viewport for 4 seconds */
	Show_4_Seconds  = 4,

	/* Display the message in the viewport for 5 seconds */
	Show_5_Seconds  = 5,

	/* Display the message in the viewport for 10 seconds */
	Show_10_Seconds = 10,

	/* Display the message in the viewport for 20 seconds */
	Show_20_Seconds = 20,

	/* Display the message in the viewport for 30 seconds */
	Show_30_Seconds = 30,

	/* Display the message in the viewport for 40 seconds */
	Show_40_Seconds = 40,

	/* Display the message in the viewport for 50 seconds */
	Show_50_Seconds = 50,

	/* Display the message in the viewport for 60 seconds */
	Show_60_Seconds = 60,

	/* Display the message in the viewport for 70 seconds */
	Show_70_Seconds = 70,

	/* Display the message in the viewport for 80 seconds */
	Show_80_Seconds = 80,

	/* Display the message in the viewport for 90 seconds */
	Show_90_Seconds = 90,

	/* Display the message in the viewport for 1 minutes */
	Show_1_Minutes  = 101,

	/* Display the message in the viewport for 2 minutes */
	Show_2_Minutes  = 102,

	/* Display the message in the viewport for 3 minutes */
	Show_3_Minutes  = 103,

	/* Display the message in the viewport for 4 minutes */
	Show_4_Minutes  = 104,

	/* Display the message in the viewport for 5 minutes */
	Show_5_Minutes  = 105,
};

/* A library containing assorted useful functions for blueprint error handling.
 *
 */
UCLASS(MinimalAPI)
class UlxBlueprintErrorLibrary : public UBlueprintFunctionLibrary
{
	GENERATED_BODY()

public:
    // The Format Error Message blueprint node macroexpands, the following
    // function is the core of the expansion.  The actual K2Node itself is in
    // its own source file.
    //
	UFUNCTION(BlueprintCallable, meta=(WorldContext = "Context", BlueprintInternalUseOnly = "true"))
	static void FormatErrorInternal(UObject *Context, ElxLogVerbosity Verbosity, ElxErrorDisplayDuration DisplayDuration, const FString &InPattern, TArray<FFormatArgumentData> InArgs);

    // Convert an ElxLogVerbosity to an ELogVerbosity::Type
    //
    static ELogVerbosity::Type ConvertElxLogVerbosity(ElxLogVerbosity Verbosity);
};

/* Debug Blueprint Errors output device. 
 *
 * When an error message gets written to the log, using "Format Error Message,"
 * or any other means that writes an error message to the log,
 * we can optionally notify the blueprint debugger to pause execution.
 * This only affects errors that are generated during blueprint execution.
 * Errors in other threads do not pause the blueprint.
 *
 */
struct FlxDebugBlueprintErrorsOutputDevice : public FOutputDevice
{
public:
    // The constructor and destructor automatically register this output device with GLog.
    //
    // This struct doesn't store the sensitivity threshold.  It relies on some blueprint
    // class to do that, so that the threshold can be easily edited with the blueprint
    // editor.  This struct must be initialized with a reference to the threshold variable.
    //
    FlxDebugBlueprintErrorsOutputDevice(const ElxLogVerbosity &SensitivityRef);
    ~FlxDebugBlueprintErrorsOutputDevice();

    // Inspect a log message.
    //
    INTEGRATION_API virtual void Serialize(const TCHAR* V, ELogVerbosity::Type Verbosity, const FName& Category) override;

    // If the device is marked 'CanBeUsedOnMultipleThreads,' then UE_LOG will
    // call Serialize from the current thread, otherwise, it will call Serialize from
    // the logging thread.  Using the logging thread would defeat the purpose of this
    // device, so it's imperative that we set this flag.
    //
    INTEGRATION_API virtual bool CanBeUsedOnMultipleThreads() const override { return true; }

private:
    const ElxLogVerbosity &Sensitivity;
};