aboutsummaryrefslogtreecommitdiff
path: root/libbb/parse_config.c
blob: 9a85786d8c295e089e53f32bba21c5224fe4020c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/* vi: set sw=4 ts=4: */
/*
 * config file parser helper
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

#if defined ENABLE_PARSE && ENABLE_PARSE
int parse_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int parse_main(int argc UNUSED_PARAM, char **argv)
{
	const char *delims = "# \t";
	unsigned flags = PARSE_NORMAL;
	int mintokens = 0, ntokens = 128;

	opt_complementary = "-1:n+:m+:f+";
	getopt32(argv, "n:m:d:f:", &ntokens, &mintokens, &delims, &flags);
	//argc -= optind;
	argv += optind;
	while (*argv) {
		parser_t *p = config_open(*argv);
		if (p) {
			int n;
			char **t = xmalloc(sizeof(char *) * ntokens);
			while ((n = config_read(p, t, ntokens, mintokens, delims, flags)) != 0) {
				for (int i = 0; i < n; ++i)
					printf("[%s]", t[i]);
				puts("");
			}
			config_close(p);
		}
		argv++;
	}
	return EXIT_SUCCESS;
}
#endif

/*

Typical usage:

----- CUT -----
	char *t[3];	// tokens placeholder
	parser_t *p = config_open(filename);
	if (p) {
		// parse line-by-line
		while (config_read(p, t, 3, 0, delimiters, flags)) { // 1..3 tokens
			// use tokens
			bb_error_msg("TOKENS: [%s][%s][%s]", t[0], t[1], t[2]);
		}
		...
		// free parser
		config_close(p);
	}
----- CUT -----

*/

parser_t* FAST_FUNC config_open2(const char *filename, FILE* FAST_FUNC (*fopen_func)(const char *path))
{
	FILE* fp;
	parser_t *parser;

	fp = fopen_func(filename);
	if (!fp)
		return NULL;
	parser = xzalloc(sizeof(*parser));
	parser->fp = fp;
	return parser;
}

parser_t* FAST_FUNC config_open(const char *filename)
{
	return config_open2(filename, fopen_or_warn_stdin);
}

static void config_free_data(parser_t *const parser)
{
	free(parser->line);
	parser->line = NULL;
	if (PARSE_KEEP_COPY) { /* compile-time constant */
		free(parser->data);
		parser->data = NULL;
	}
}

void FAST_FUNC config_close(parser_t *parser)
{
	if (parser) {
		config_free_data(parser);
		fclose(parser->fp);
		free(parser);
	}
}

/*
0. If parser is NULL return 0.
1. Read a line from config file. If nothing to read then return 0.
   Handle continuation character. Advance lineno for each physical line.
   Discard everything past comment characher.
2. if PARSE_TRIM is set (default), remove leading and trailing delimiters.
3. If resulting line is empty goto 1.
4. Look for first delimiter. If !PARSE_COLLAPSE or !PARSE_TRIM is set then
   remember the token as empty.
5. Else (default) if number of seen tokens is equal to max number of tokens
   (token is the last one) and PARSE_GREEDY is set then the remainder
   of the line is the last token.
   Else (token is not last or PARSE_GREEDY is not set) just replace
   first delimiter with '\0' thus delimiting the token.
6. Advance line pointer past the end of token. If number of seen tokens
   is less than required number of tokens then goto 4.
7. Check the number of seen tokens is not less the min number of tokens.
   Complain or die otherwise depending on PARSE_MIN_DIE.
8. Return the number of seen tokens.

mintokens > 0 make config_read() print error message if less than mintokens
(but more than 0) are found. Empty lines are always skipped (not warned about).
*/
#undef config_read
int FAST_FUNC config_read(parser_t *parser, char **tokens, unsigned flags, const char *delims)
{
	char *line;
	int ntokens, mintokens;
	int t, len;

	ntokens = flags & 0xFF;
	mintokens = (flags & 0xFF00) >> 8;

	if (parser == NULL)
		return 0;

again:
	memset(tokens, 0, sizeof(tokens[0]) * ntokens);
	config_free_data(parser);

	/* Read one line (handling continuations with backslash) */
	line = bb_get_chunk_with_continuation(parser->fp, &len, &parser->lineno);
	if (line == NULL)
		return 0;
	parser->line = line;

	/* Strip trailing line-feed if any */
	if (len && line[len-1] == '\n')
		line[len-1] = '\0';

	/* Skip token in the start of line? */
	if (flags & PARSE_TRIM)
		line += strspn(line, delims + 1);

	if (line[0] == '\0' || line[0] == delims[0])
		goto again;

	if (flags & PARSE_KEEP_COPY)
		parser->data = xstrdup(line);

	/* Tokenize the line */
	for (t = 0; *line && *line != delims[0] && t < ntokens; t++) {
		/* Pin token */
		tokens[t] = line;

		/* Combine remaining arguments? */
		if ((t != (ntokens-1)) || !(flags & PARSE_GREEDY)) {
			/* Vanilla token, find next delimiter */
			line += strcspn(line, delims[0] ? delims : delims + 1);
		} else {
			/* Combining, find comment char if any */
			line = strchrnul(line, delims[0]);

			/* Trim any extra delimiters from the end */
			if (flags & PARSE_TRIM) {
				while (strchr(delims + 1, line[-1]) != NULL)
					line--;
			}
		}

		/* Token not terminated? */
		if (line[0] == delims[0])
			*line = '\0';
		else if (line[0] != '\0')
			*(line++) = '\0';

#if 0 /* unused so far */
		if (flags & PARSE_ESCAPE) {
			const char *from;
			char *to;

			from = to = tokens[t];
			while (*from) {
				if (*from == '\\') {
					from++;
					*to++ = bb_process_escape_sequence(&from);
				} else {
					*to++ = *from++;
				}
			}
			*to = '\0';
		}
#endif

		/* Skip possible delimiters */
		if (flags & PARSE_COLLAPSE)
			line += strspn(line, delims + 1);
	}

	if (t < mintokens) {
		bb_error_msg("bad line %u: %d tokens found, %d needed",
				parser->lineno, t, mintokens);
		if (flags & PARSE_MIN_DIE)
			xfunc_die();
		goto again;
	}

	return t;
}