common: split ini-config in its own convenience library

[lttng-tools.git] / src / common / ini-config / ini.cpp

/*
 * inih -- simple .INI file parser
 *
 * The "inih" library is distributed under the New BSD license:
 *
 * Copyright (C) 2009 Brush Technology - All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *     * Neither the name of Brush Technology nor the names of its contributors
 *     may be used to endorse or promote products derived from this software
 *     without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY BRUSH TECHNOLOGY ''AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL BRUSH TECHNOLOGY BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * http://code.google.com/p/inih/
 */

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <common/common.h>

#include "ini.h"

#if !INI_USE_STACK
#include <stdlib.h>
#endif

#define MAX_SECTION 50
#define MAX_NAME 50

/* Strip whitespace chars off end of given string, in place. Return s. */
static char* rstrip(char* s)
{
	char* p = s + strlen(s);

	while (p > s && isspace((unsigned char)(*--p)))
		*p = '\0';
	return s;
}

/* Return pointer to first non-whitespace char in given string. */
static char* lskip(const char* s)
{
	while (*s && isspace((unsigned char)(*s)))
		s++;
	return (char*)s;
}

/*
 * Return pointer to first char c or ';' comment in given string, or pointer to
 * null at end of string if neither found. ';' must be prefixed by a whitespace
 * character to register as a comment.
 */
static char* find_char_or_comment(const char* s, char c)
{
	int was_whitespace = 0;

	while (*s && *s != c && !(was_whitespace && *s == ';')) {
		was_whitespace = isspace((unsigned char)(*s));
		s++;
	}
	return (char*)s;
}

/* Version of strncpy that ensures dest (size bytes) is null-terminated. */
static char* strncpy0(char* dest, const char* src, size_t size)
{
	strncpy(dest, src, size - 1);
	dest[size - 1] = '\0';
	return dest;
}

/* See documentation in header file. */
int ini_parse_file(FILE* file, ini_entry_handler handler, void* user)
{
	/* Uses a fair bit of stack (use heap instead if you need to) */
#if INI_USE_STACK
	char line[INI_MAX_LINE];
#else
	char* line;
#endif
	char section[MAX_SECTION] = "";
	char prev_name[MAX_NAME] = "";

	char* start;
	char* end;
	char* name;
	char* value;
	int lineno = 0;
	int error = 0;

#if !INI_USE_STACK
	line = (char*)zmalloc(INI_MAX_LINE);
	if (!line) {
		return -2;
	}
#endif

	/* Scan through file line by line */
	while (fgets(line, INI_MAX_LINE, file) != NULL) {
		lineno++;

		start = line;
#if INI_ALLOW_BOM
		if (lineno == 1 && (unsigned char)start[0] == 0xEF &&
			(unsigned char)start[1] == 0xBB &&
			(unsigned char)start[2] == 0xBF) {
			start += 3;
		}
#endif
		start = lskip(rstrip(start));

		if (*start == ';' || *start == '#') {
			/*
			 * Per Python ConfigParser, allow '#' comments at
			 * start of line.
			 */
		}
#if INI_ALLOW_MULTILINE
		else if (*prev_name && *start && start > line) {
			/* Non-black line with leading whitespace, treat as
			 * continuation of previous name's value
			 * (as per Python ConfigParser).
			 */
			if (handler(user, section, prev_name, start) < 0 &&
				!error) {
				error = lineno;
			}
		}
#endif
		else if (*start == '[') {
			/* A "[section]" line */
			end = find_char_or_comment(start + 1, ']');
			if (*end == ']') {
				*end = '\0';
				strncpy0(section, start + 1, sizeof(section));
				*prev_name = '\0';
			}
			else if (!error) {
				/* No ']' found on section line */
				error = lineno;
			}
		}
		else if (*start && *start != ';') {
			/* Not a comment, must be a name[=:]value pair */
			end = find_char_or_comment(start, '=');
			if (*end != '=') {
				end = find_char_or_comment(start, ':');
			}
			if (*end == '=' || *end == ':') {
				*end = '\0';
				name = rstrip(start);
				value = lskip(end + 1);
				end = find_char_or_comment(value, '\0');
				if (*end == ';') {
					*end = '\0';
				}

				rstrip(value);

				/*
				 * Valid name[=:]value pair found, call
				 * handler
				 */
				strncpy0(prev_name, name, sizeof(prev_name));
				if (handler(user, section, name, value) < 0 &&
					!error) {
					error = lineno;
				}
			}
			else if (!error) {
				/* No '=' or ':' found on name[=:]value line */
				error = lineno;
			}
		}
	}

#if !INI_USE_STACK
	free(line);
#endif

	return error;
}

/* See documentation in header file. */
int ini_parse(const char* filename, ini_entry_handler handler, void* user)
{
	FILE* file;
	int error;

	file = fopen(filename, "r");
	if (!file) {
		return -1;
	}

	error = ini_parse_file(file, handler, user);
	fclose(file);
	return error;
}