a

readcons.c

@@ -0,0 +1,110 @@
+#include <u.h>
+#include <libc.h>
+#include "drawterm.h"
+
+void*
+erealloc(void *v, ulong n)
+{
+	v = realloc(v, n);
+	if(v == nil)
+		sysfatal("out of memory");
+	return v;
+}
+
+char*
+estrdup(char *s)
+{
+	s = strdup(s);
+	if(s == nil)
+		sysfatal("out of memory");
+	return s;
+}
+
+char*
+estrappend(char *s, char *fmt, ...)
+{
+	char *t;
+	va_list arg;
+
+	va_start(arg, fmt);
+	t = vsmprint(fmt, arg);
+	if(t == nil)
+		sysfatal("out of memory");
+	va_end(arg);
+	s = erealloc(s, strlen(s)+strlen(t)+1);
+	strcat(s, t);
+	free(t);
+	return s;
+}
+
+/*
+ *  prompt for a string with a possible default response
+ */
+char*
+readcons(char *prompt, char *def, int raw)
+{
+	int fdin, fdout, ctl, n;
+	char line[10];
+	char *s;
+
+	fdin = open("/dev/cons", OREAD);
+	if(fdin < 0)
+		fdin = 0;
+	fdout = open("/dev/cons", OWRITE);
+	if(fdout < 0)
+		fdout = 1;
+	if(def != nil)
+		fprint(fdout, "%s[%s]: ", prompt, def);
+	else
+		fprint(fdout, "%s: ", prompt);
+	if(raw){
+		ctl = open("/dev/consctl", OWRITE);
+		if(ctl >= 0)
+			write(ctl, "rawon", 5);
+	} else
+		ctl = -1;
+	s = estrdup("");
+	for(;;){
+		n = read(fdin, line, 1);
+		if(n == 0){
+		Error:
+			close(fdin);
+			close(fdout);
+			if(ctl >= 0)
+				close(ctl);
+			free(s);
+			return nil;
+		}
+		if(n < 0)
+			goto Error;
+		if(line[0] == 0x7f)
+			goto Error;
+		if(n == 0 || line[0] == '\n' || line[0] == '\r'){
+			if(raw){
+				write(ctl, "rawoff", 6);
+				write(fdout, "\n", 1);
+			}
+			close(ctl);
+			close(fdin);
+			close(fdout);
+			if(*s == 0 && def != nil)
+				s = estrappend(s, "%s", def);
+			return s;
+		}
+		if(line[0] == '\b'){
+			if(strlen(s) > 0)
+				s[strlen(s)-1] = 0;
+		} else if(line[0] == 0x15) {	/* ^U: line kill */
+			if(def != nil)
+				fprint(fdout, "\n%s[%s]: ", prompt, def);
+			else
+				fprint(fdout, "\n%s: ", prompt);
+			
+			s[0] = 0;
+		} else {
+			s = estrappend(s, "%c", line[0]);
+		}
+	}
+	return nil; /* not reached */
+}
+