simplescim_error_string.cpp

/**
 *  This file is part of the EGIL SCIM client.
 *
 *  Copyright (C) 2017-2019 Föreningen Sambruk
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or (at your option) any later version.

 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.

 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "simplescim_error_string.hpp"

#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>

#ifdef _WIN32
// We use strerror instead of strerror_s as MSVC thinks we should use
#pragma warning( disable : 4996 )
#endif

static int prefix_present = 0;
static char prefix_buffer[1024];

static int message_present = 0;
static char message_buffer[1024];

static char error_string_buffer[2051];

static const char *no_error = "No error";

bool has_errors_to_print() {
	return prefix_present || message_present;
}

/**
 * Returns an error string that contains the latest error
 * message generated by SimpleSCIM or "No error" if no
 * error string has been set.
 */
const char *simplescim_error_string_get() {
	if (!prefix_present && !message_present) {
		return no_error;
	}

	if (!prefix_present) {
		return message_buffer;
	}

	if (!message_present) {
		return prefix_buffer;
	}

	snprintf(error_string_buffer,
	         sizeof(error_string_buffer),
	         "%s: %s",
	         prefix_buffer,
	         message_buffer);

	return error_string_buffer;
}

/**
 * Sets the prefix of the error string with 'prefix' as the
 * format string. If a message has been set, the prefix
 * will appear before the message with a colon and a space
 * appended. If no message has been set, the prefix will
 * appear as is. nullptr signifies no prefix.
 */
void simplescim_error_string_set_prefix(const char *prefix, ...) {
	va_list ap;

	if (prefix == nullptr) {
		prefix_present = 0;
	} else {
		prefix_present = 1;
		va_start(ap, prefix);
		vsnprintf(prefix_buffer,
		          sizeof(prefix_buffer),
		          prefix,
		          ap);
		va_end(ap);
	}
}

/**
 * Sets the message of the error string with 'message' as
 * the format string. nullptr signifies no message.
 */
void simplescim_error_string_set_message(const char *message, ...) {
	va_list ap;

	if (message == nullptr) {
		message_present = 0;
	} else {
		message_present = 1;
		va_start(ap, message);
		vsnprintf(message_buffer,
		          sizeof(message_buffer),
		          message,
		          ap);
		va_end(ap);
	}
}

/**
 * Sets the prefix of the error string with 'prefix' as the
 * format string and sets the message of the error string
 * to strerror(errno). nullptr signifies no prefix.
 */
void simplescim_error_string_set_errno(const char *prefix, ...) {
	va_list ap;
	int tmp_errno;

	tmp_errno = errno;

	/* Set prefix */
	if (prefix == nullptr) {
		prefix_present = 0;
	} else {
		prefix_present = 1;
		va_start(ap, prefix);
		vsnprintf(prefix_buffer,
		          sizeof(prefix_buffer),
		          prefix,
		          ap);
		va_end(ap);
	}

	/* Set message */
	message_present = 1;
	snprintf(message_buffer,
	         sizeof(message_buffer),
	         "%s",
	         strerror(tmp_errno));
}

/**
 * Sets the prefix of the error string to 'prefix' and sets
 * the message of the error string to 'message'.
 * 'prefix' == nullptr signifies no prefix and
 * 'message' == nullptr signifies no message.
 */
void simplescim_error_string_set(const char *prefix,
                                 const char *message) {
	/* Set prefix */
	if (prefix == nullptr) {
		prefix_present = 0;
	} else {
		prefix_present = 1;
		snprintf(prefix_buffer,
		         sizeof(prefix_buffer),
		         "%s",
		         prefix);
	}

	/* Set message */
	if (message == nullptr) {
		message_present = 0;
	} else {
		message_present = 1;
		snprintf(message_buffer,
		         sizeof(message_buffer),
		         "%s",
		         message);
	}
}