godot/core/error_macros.h

/*************************************************************************/
/*  error_macros.h                                                       */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
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#ifndef ERROR_MACROS_H
#define ERROR_MACROS_H

/**
 * Error macros. Unlike exceptions and asserts, these macros try to mantain consistency and stability
 * inside the code. It is recommended to always return processable data, so in case of an error, the
 * engine can stay working well.
 * In most cases, bugs and/or invalid data are not fatal and should never allow a perfectly running application
 * to fail or crash.
 */

/**
 * Pointer to the error macro priting function. Reassign to any function to have errors printed
 */

/** Function used by the error macros */

// function, file, line, error, explanation

enum ErrorHandlerType {
	ERR_HANDLER_ERROR,
	ERR_HANDLER_WARNING,
	ERR_HANDLER_SCRIPT
};

typedef void (*ErrorHandlerFunc)(void *, const char *, const char *, int p_line, const char *, const char *, ErrorHandlerType p_type);
void _err_set_last_error(const char *p_err);
void _err_clear_last_error();

struct ErrorHandlerList {

	ErrorHandlerFunc errfunc;
	void *userdata;

	ErrorHandlerList *next;

	ErrorHandlerList() {
		errfunc = 0;
		next = 0;
		userdata = 0;
	}
};

void add_error_handler(ErrorHandlerList *p_handler);
void remove_error_handler(ErrorHandlerList *p_handler);

void _err_print_error(const char *p_function, const char *p_file, int p_line, const char *p_error, ErrorHandlerType p_type = ERR_HANDLER_ERROR);

#ifndef _STR
#define _STR(m_x) #m_x
#define _MKSTR(m_x) _STR(m_x)
#endif

#define _FNL __FILE__ ":"

/** An index has failed if m_index<0 or m_index >=m_size, the function exists */

extern bool _err_error_exists;

#ifdef DEBUG_ENABLED
/** Print a warning string.
 */
#define ERR_EXPLAINC(m_reason)         \
	{                                  \
		_err_set_last_error(m_reason); \
		_err_error_exists = true;      \
	}
#define ERR_EXPLAIN(m_string)                                    \
	{                                                            \
		_err_set_last_error(String(m_string).utf8().get_data()); \
		_err_error_exists = true;                                \
	}

#else

#define ERR_EXPLAIN(m_text)
#define ERR_EXPLAINC(m_text)

#endif

#ifdef __GNUC__
//#define FUNCTION_STR __PRETTY_FUNCTION__ - too annoying
#define FUNCTION_STR __FUNCTION__
#else
#define FUNCTION_STR __FUNCTION__
#endif

// (*): See https://stackoverflow.com/questions/257418/do-while-0-what-is-it-good-for

#define ERR_FAIL_INDEX(m_index, m_size)                                                                                    \
	do {                                                                                                                   \
		if ((m_index) < 0 || (m_index) >= (m_size)) {                                                                      \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Index " _STR(m_index) " out of size (" _STR(m_size) ")."); \
			return;                                                                                                        \
		} else                                                                                                             \
			_err_error_exists = false;                                                                                     \
	} while (0); // (*)

/** An index has failed if m_index<0 or m_index >=m_size, the function exists.
  * This function returns an error value, if returning Error, please select the most
  * appropriate error condition from error_macros.h
  */

#define ERR_FAIL_INDEX_V(m_index, m_size, m_retval)                                                                        \
	do {                                                                                                                   \
		if ((m_index) < 0 || (m_index) >= (m_size)) {                                                                      \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Index " _STR(m_index) " out of size (" _STR(m_size) ")."); \
			return m_retval;                                                                                               \
		} else                                                                                                             \
			_err_error_exists = false;                                                                                     \
	} while (0); // (*)

/** Use this one if there is no sensible fallback, that is, the error is unrecoverable.
	* We'll do UB by returning a null reference and pray that we wont't crash.
	*/
#define PRAY_BAD_INDEX(m_index, m_size, m_type)                                                                                    \
	do {                                                                                                                           \
		if ((m_index) < 0 || (m_index) >= (m_size)) {                                                                              \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "SEVERE: Index " _STR(m_index) " out of size (" _STR(m_size) ")."); \
			m_type *n = (m_type *)0; /* two-step to avoid warning */                                                               \
			return *n;                                                                                                             \
		} else                                                                                                                     \
			_err_error_exists = false;                                                                                             \
	} while (0); // (*)

/** An error condition happened (m_cond tested true) (WARNING this is the opposite as assert().
  * the function will exit.
  */

#define ERR_FAIL_NULL(m_param)                                                                              \
	{                                                                                                       \
		if (!m_param) {                                                                                     \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Parameter ' " _STR(m_param) " ' is null."); \
			return;                                                                                         \
		} else                                                                                              \
			_err_error_exists = false;                                                                      \
	}

#define ERR_FAIL_NULL_V(m_param, m_retval)                                                                  \
	{                                                                                                       \
		if (!m_param) {                                                                                     \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Parameter ' " _STR(m_param) " ' is null."); \
			return m_retval;                                                                                \
		} else                                                                                              \
			_err_error_exists = false;                                                                      \
	}

/** An error condition happened (m_cond tested true) (WARNING this is the opposite as assert().
 * the function will exit.
 */

#define ERR_FAIL_COND(m_cond)                                                                              \
	{                                                                                                      \
		if (m_cond) {                                                                                      \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Condition ' " _STR(m_cond) " ' is true."); \
			return;                                                                                        \
		} else                                                                                             \
			_err_error_exists = false;                                                                     \
	}

/** An error condition happened (m_cond tested true) (WARNING this is the opposite as assert().
 * the function will exit.
 * This function returns an error value, if returning Error, please select the most
 * appropriate error condition from error_macros.h
 */

#define ERR_FAIL_COND_V(m_cond, m_retval)                                                                                            \
	{                                                                                                                                \
		if (m_cond) {                                                                                                                \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Condition ' " _STR(m_cond) " ' is true. returned: " _STR(m_retval)); \
			return m_retval;                                                                                                         \
		} else                                                                                                                       \
			_err_error_exists = false;                                                                                               \
	}

/** Use this one if there is no sensible fallback, that is, the error is unrecoverable.
  *  We'll do UB by returning a null reference and pray that we wont't crash.
  */

#define PRAY_COND(m_cond, m_type)                                                                                  \
	{                                                                                                              \
		if (m_cond) {                                                                                              \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "SEVERE: Condition ' " _STR(m_cond) " ' is true."); \
			m_type *n = (m_type *)0; /* two-step to avoid warning */                                               \
			return *n;                                                                                             \
		} else                                                                                                     \
			_err_error_exists = false;                                                                             \
	}

/** An error condition happened (m_cond tested true) (WARNING this is the opposite as assert().
 * the loop will skip to the next iteration.
 */

#define ERR_CONTINUE(m_cond)                                                                                             \
	{                                                                                                                    \
		if (m_cond) {                                                                                                    \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Condition ' " _STR(m_cond) " ' is true. Continuing..:"); \
			continue;                                                                                                    \
		} else                                                                                                           \
			_err_error_exists = false;                                                                                   \
	}

/** An error condition happened (m_cond tested true) (WARNING this is the opposite as assert().
 * the loop will break
 */

#define ERR_BREAK(m_cond)                                                                                              \
	{                                                                                                                  \
		if (m_cond) {                                                                                                  \
			_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Condition ' " _STR(m_cond) " ' is true. Breaking..:"); \
			break;                                                                                                     \
		} else                                                                                                         \
			_err_error_exists = false;                                                                                 \
	}

/** Print an error string and return
 */

#define ERR_FAIL()                                                                     \
	{                                                                                  \
		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Method/Function Failed."); \
		_err_error_exists = false;                                                     \
		return;                                                                        \
	}

/** Print an error string and return with value
 */

#define ERR_FAIL_V(m_value)                                                                                       \
	{                                                                                                             \
		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "Method/Function Failed, returning: " __STR(m_value)); \
		_err_error_exists = false;                                                                                \
		return m_value;                                                                                           \
	}

/** Use this one if there is no sensible fallback, that is, the error is unrecoverable.
  *  We'll do UB by returning a null reference and pray that we wont't crash.
  */

#define PRAY(m_type)                                                                           \
	{                                                                                          \
		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, "SEVERE: Method/Function Failed."); \
		m_type *n = (m_type *)0; /* two-step to avoid warning */                               \
		return *n;                                                                             \
	}

/** Print an error string.
 */

#define ERR_PRINT(m_string)                                           \
	{                                                                 \
		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, m_string); \
		_err_error_exists = false;                                    \
	}

#define ERR_PRINTS(m_string)                                                                    \
	{                                                                                           \
		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, String(m_string).utf8().get_data()); \
		_err_error_exists = false;                                                              \
	}

/** Print a warning string.
 */

#define WARN_PRINT(m_string)                                                               \
	{                                                                                      \
		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, m_string, ERR_HANDLER_WARNING); \
		_err_error_exists = false;                                                         \
	}

#define WARN_PRINTS(m_string)                                                                                        \
	{                                                                                                                \
		_err_print_error(FUNCTION_STR, __FILE__, __LINE__, String(m_string).utf8().get_data(), ERR_HANDLER_WARNING); \
		_err_error_exists = false;                                                                                   \
	}

#endif