1 #include	"mk.h"
2 
3 /*
4  *	This file contains functions that depend on rc's syntax.  Most
5  *	of the routines extract strings observing rc's escape conventions
6  */
7 
8 
9 /*
10  *	skip a token in single quotes.
11  */
12 static char *
13 squote(char *cp)
14 {
15 	Rune r;
16 	int n;
17 
18 	while(*cp){
19 		n = chartorune(&r, cp);
20 		if(r == '\'') {
21 			n += chartorune(&r, cp+n);
22 			if(r != '\'')
23 				return(cp);
24 		}
25 		cp += n;
26 	}
27 	SYNERR(-1);		/* should never occur */
28 	fprint(2, "missing closing '\n");
29 	return 0;
30 }
31 
32 /*
33  *	search a string for characters in a pattern set
34  *	characters in quotes and variable generators are escaped
35  */
36 char *
37 rccharin(char *cp, char *pat)
38 {
39 	Rune r;
40 	int n, vargen;
41 
42 	vargen = 0;
43 	while(*cp){
44 		n = chartorune(&r, cp);
45 		switch(r){
46 		case '\'':			/* skip quoted string */
47 			cp = squote(cp+1);	/* n must = 1 */
48 			if(!cp)
49 				return 0;
50 			break;
51 		case '$':
52 			if(*(cp+1) == '{')
53 				vargen = 1;
54 			break;
55 		case '}':
56 			if(vargen)
57 				vargen = 0;
58 			else if(utfrune(pat, r))
59 				return cp;
60 			break;
61 		default:
62 			if(vargen == 0 && utfrune(pat, r))
63 				return cp;
64 			break;
65 		}
66 		cp += n;
67 	}
68 	if(vargen){
69 		SYNERR(-1);
70 		fprint(2, "missing closing } in pattern generator\n");
71 	}
72 	return 0;
73 }
74 
75 /*
76  *	extract an escaped token.  Possible escape chars are single-quote,
77  *	double-quote,and backslash.  Only the first is valid for rc. the
78  *	others are just inserted into the receiving buffer.
79  */
80 char*
81 rcexpandquote(char *s, Rune r, Bufblock *b)
82 {
83 	if (r != '\'') {
84 		rinsert(b, r);
85 		return s;
86 	}
87 
88 	while(*s){
89 		s += chartorune(&r, s);
90 		if(r == '\'') {
91 			if(*s == '\'')
92 				s++;
93 			else
94 				return s;
95 		}
96 		rinsert(b, r);
97 	}
98 	return 0;
99 }
100 
101 /*
102  *	Input an escaped token.  Possible escape chars are single-quote,
103  *	double-quote and backslash.  Only the first is a valid escape for
104  *	rc; the others are just inserted into the receiving buffer.
105  */
106 int
107 rcescapetoken(Biobuf *bp, Bufblock *buf, int preserve, int esc)
108 {
109 	int c, line;
110 
111 	if(esc != '\'')
112 		return 1;
113 
114 	line = mkinline;
115 	while((c = nextrune(bp, 0)) > 0){
116 		if(c == '\''){
117 			if(preserve)
118 				rinsert(buf, c);
119 			c = Bgetrune(bp);
120 			if (c < 0)
121 				break;
122 			if(c != '\''){
123 				Bungetrune(bp);
124 				return 1;
125 			}
126 		}
127 		rinsert(buf, c);
128 	}
129 	SYNERR(line); fprint(2, "missing closing %c\n", esc);
130 	return 0;
131 }
132 
133 /*
134  *	copy a single-quoted string; s points to char after opening quote
135  */
136 static char *
137 copysingle(char *s, Bufblock *buf)
138 {
139 	Rune r;
140 
141 	while(*s){
142 		s += chartorune(&r, s);
143 		rinsert(buf, r);
144 		if(r == '\'')
145 			break;
146 	}
147 	return s;
148 }
149 /*
150  *	check for quoted strings.  backquotes are handled here; single quotes above.
151  *	s points to char after opening quote, q.
152  */
153 char *
154 rccopyq(char *s, Rune q, Bufblock *buf)
155 {
156 	if(q == '\'')				/* copy quoted string */
157 		return copysingle(s, buf);
158 
159 	if(q != '`')				/* not quoted */
160 		return s;
161 
162 	while(*s){				/* copy backquoted string */
163 		s += chartorune(&q, s);
164 		rinsert(buf, q);
165 		if(q == '}')
166 			break;
167 		if(q == '\'')
168 			s = copysingle(s, buf);	/* copy quoted string */
169 	}
170 	return s;
171 }
172 
173 static int
174 rcmatchname(char *name)
175 {
176 	char *p;
177 
178 	if((p = strrchr(name, '/')) != nil)
179 		name = p+1;
180 	if(name[0] == 'r' && name[1] == 'c')
181 		return 1;
182 	return 0;
183 }
184 
185 Shell rcshell = {
186 	"rc",
187 	"'= \t",
188 	'\1',
189 	rccharin,
190 	rcexpandquote,
191 	rcescapetoken,
192 	rccopyq,
193 	rcmatchname
194 };