1 /* Licensed under GPLv3+ - see LICENSE file for details */
2 #include <ccan/opt/opt.h>
10 /* We only use this for pointer comparisons. */
11 const char opt_hidden[1];
13 #define MIN_DESC_WIDTH 40
14 #define MIN_TOTAL_WIDTH 50
16 static unsigned int get_columns(void)
19 const char *env = getenv("COLUMNS");
25 if (ioctl(0, TIOCGWINSZ, &w) == -1)
33 /* Return number of chars of words to put on this line.
34 * Prefix is set to number to skip at start, maxlen is max width, returns
35 * length (after prefix) to put on this line. */
36 static size_t consume_words(const char *words, size_t maxlen, size_t *prefix)
40 /* Swallow leading whitespace. */
41 *prefix = strspn(words, " ");
44 /* Use at least one word, even if it takes us over maxlen. */
45 oldlen = len = strcspn(words, " ");
46 while (len <= maxlen) {
48 len += strspn(words+len, " ");
49 len += strcspn(words+len, " ");
57 static char *add_str_len(char *base, size_t *len, size_t *max,
58 const char *str, size_t slen)
60 if (slen >= *max - *len)
61 base = realloc(base, *max = (*max * 2 + slen + 1));
62 memcpy(base + *len, str, slen);
67 static char *add_str(char *base, size_t *len, size_t *max, const char *str)
69 return add_str_len(base, len, max, str, strlen(str));
72 static char *add_indent(char *base, size_t *len, size_t *max, size_t indent)
74 if (indent >= *max - *len)
75 base = realloc(base, *max = (*max * 2 + indent + 1));
76 memset(base + *len, ' ', indent);
81 static char *add_desc(char *base, size_t *len, size_t *max,
82 unsigned int indent, unsigned int width,
83 const struct opt_table *opt)
85 size_t off, prefix, l;
87 bool same_line = false;
89 base = add_str(base, len, max, opt->names);
90 off = strlen(opt->names);
91 if (opt->type == OPT_HASARG
92 && !strchr(opt->names, ' ')
93 && !strchr(opt->names, '=')) {
94 base = add_str(base, len, max, " <arg>");
95 off += strlen(" <arg>");
98 /* Do we start description on next line? */
99 if (off + 2 > indent) {
100 base = add_str(base, len, max, "\n");
103 base = add_indent(base, len, max, indent - off);
108 /* Indent description. */
110 while ((l = consume_words(p, width - indent, &prefix)) != 0) {
112 base = add_indent(base, len, max, indent);
114 base = add_str_len(base, len, max, p, l);
115 base = add_str(base, len, max, "\n");
121 /* Empty description? Make it match normal case. */
123 base = add_str(base, len, max, "\n");
126 char buf[OPT_SHOW_LEN + sizeof("...")];
127 strcpy(buf + OPT_SHOW_LEN, "...");
128 opt->show(buf, opt->u.arg);
130 /* If it doesn't fit on this line, indent. */
131 if (off + strlen(" (default: ") + strlen(buf) + strlen(")")
133 base = add_indent(base, len, max, indent);
139 base = add_str(base, len, max, " (default: ");
140 base = add_str(base, len, max, buf);
141 base = add_str(base, len, max, ")\n");
146 char *opt_usage(const char *argv0, const char *extra)
149 size_t max, len, width, indent;
152 width = get_columns();
153 if (width < MIN_TOTAL_WIDTH)
154 width = MIN_TOTAL_WIDTH;
156 /* Figure out longest option. */
158 for (i = 0; i < opt_count; i++) {
160 if (opt_table[i].desc == opt_hidden)
162 if (opt_table[i].type == OPT_SUBTABLE)
164 l = strlen(opt_table[i].names);
165 if (opt_table[i].type == OPT_HASARG
166 && !strchr(opt_table[i].names, ' ')
167 && !strchr(opt_table[i].names, '='))
168 l += strlen(" <arg>");
173 /* Now we know how much to indent */
174 if (indent + MIN_DESC_WIDTH > width)
175 indent = width - MIN_DESC_WIDTH;
180 ret = add_str(ret, &len, &max, "Usage: ");
181 ret = add_str(ret, &len, &max, argv0);
183 /* Find usage message from among registered options if necessary. */
186 for (i = 0; i < opt_count; i++) {
187 if (opt_table[i].cb == (void *)opt_usage_and_exit
188 && opt_table[i].u.carg) {
189 extra = opt_table[i].u.carg;
194 ret = add_str(ret, &len, &max, " ");
195 ret = add_str(ret, &len, &max, extra);
196 ret = add_str(ret, &len, &max, "\n");
198 for (i = 0; i < opt_count; i++) {
199 if (opt_table[i].desc == opt_hidden)
201 if (opt_table[i].type == OPT_SUBTABLE) {
202 ret = add_str(ret, &len, &max, opt_table[i].desc);
203 ret = add_str(ret, &len, &max, ":\n");
206 ret = add_desc(ret, &len, &max, indent, width, &opt_table[i]);