vac: add -a and -x flags

Thanks to Michael Kaminsky for the suggestion.

src/cmd/vac/glob.c

@@ -0,0 +1,180 @@
+#include "stdinc.h"
+#include "vac.h"
+#include "dat.h"
+#include "fns.h"
+#include "error.h"
+
+// Convert globbish pattern to regular expression
+// The wildcards are
+//
+//	*	any non-slash characters
+//	...	any characters including /
+//	?	any single character except /
+//	[a-z]	character class
+//	[~a-z]	negated character class
+//
+
+Reprog*
+glob2regexp(char *glob)
+{
+	char *s, *p, *w;
+	Reprog *re;
+	int boe;	// beginning of path element
+
+	s = malloc(20*(strlen(glob)+1));
+	if(s == nil)
+		return nil;
+	w = s;
+	boe = 1;
+	*w++ = '^';
+	*w++ = '(';
+	for(p=glob; *p; p++){
+		if(p[0] == '.' && p[1] == '.' && p[2] == '.'){
+			strcpy(w, ".*");
+			w += strlen(w);
+			p += 3-1;
+			boe = 0;
+			continue;
+		}
+		if(p[0] == '*'){
+			if(boe)
+				strcpy(w, "([^./][^/]*)?");
+			else
+				strcpy(w, "[^/]*");
+			w += strlen(w);
+			boe = 0;
+			continue;
+		}
+		if(p[0] == '?'){
+			if(boe)
+				strcpy(w, "[^./]");
+			else
+				strcpy(w, "[^/]");
+			w += strlen(w);
+			boe = 0;
+			continue;
+		}
+		if(p[0] == '['){
+			*w++ = '[';
+			if(*++p == '~'){
+				*w++ = '^';
+				p++;
+			}
+			while(*p != ']'){
+				if(*p == '/')
+					goto syntax;
+				if(*p == '^' || *p == '\\')
+					*w++ = '\\';
+				*w++ = *p++;
+			}
+			*w++ = ']';
+			boe = 0;
+			continue;
+		}
+		if(strchr("()|^$[]*?+\\.", *p)){
+			*w++ = '\\';
+			*w++ = *p;
+			boe = 0;
+			continue;
+		}
+		if(*p == '/'){
+			*w++ = '/';
+			boe = 1;
+			continue;
+		}
+		*w++ = *p;
+		boe = 0;
+		continue;
+	}
+	*w++ = ')';
+	*w++ = '$';
+	*w = 0;
+	
+	re = regcomp(s);
+	if(re == nil){
+	syntax:
+		free(s);
+		werrstr("glob syntax error");
+		return nil;
+	}
+	free(s);
+	return re;
+}
+
+typedef struct Pattern Pattern;
+struct Pattern
+{
+	Reprog *re;
+	int include;
+};
+
+Pattern *pattern;
+int npattern;
+
+void
+loadexcludefile(char *file)
+{
+	Biobuf *b;
+	char *p, *q;
+	int n, inc;
+	Reprog *re;
+
+	if((b = Bopen(file, OREAD)) == nil)
+		sysfatal("open %s: %r", file);
+	for(n=1; (p=Brdstr(b, '\n', 1)) != nil; free(p), n++){
+		q = p+strlen(p);
+		while(q > p && isspace((uchar)*(q-1)))
+			*--q = 0;
+		switch(p[0]){
+		case '\0':
+		case '#':
+			continue;
+		}
+		
+		inc = 0;
+		if(strncmp(p, "include ", 8) == 0){
+			inc = 1;
+		}else if(strncmp(p, "exclude ", 8) == 0){
+			inc = 0;
+		}else
+			sysfatal("%s:%d: line does not begin with include or exclude", file, n);
+
+		if(strchr(p+8, ' '))
+			fprint(2, "%s:%d: warning: space in pattern\n", file, n);
+
+		if((re = glob2regexp(p+8)) == nil)
+			sysfatal("%s:%d: bad glob pattern", file, n);
+
+		pattern = vtrealloc(pattern, (npattern+1)*sizeof pattern[0]);
+		pattern[npattern].re = re;
+		pattern[npattern].include = inc;
+		npattern++;
+	}
+	Bterm(b);
+}
+
+void
+excludepattern(char *p)
+{
+	Reprog *re;
+	
+	if((re = glob2regexp(p)) == nil)
+		sysfatal("bad glob pattern %s", p);
+
+	pattern = vtrealloc(pattern, (npattern+1)*sizeof pattern[0]);
+	pattern[npattern].re = re;
+	pattern[npattern].include = 0;
+	npattern++;
+}
+
+int
+includefile(char *file)
+{
+	Pattern *p, *ep;
+	
+	for(p=pattern, ep=p+npattern; p<ep; p++)
+		if(regexec(p->re, file, nil, 0))
+			return p->include;
+	return 1;
+}
+