Update working directory of elvish-stub.

eval/eval.go

@@ -177,7 +177,12 @@ func (ev *Evaler) EvalInteractive(text string, n *parse.Chunk) error {
 	// XXX Should use fd of /dev/terminal instead of 0.
 	if ev.Stub != nil && sys.IsATTY(0) {
 		ev.Stub.SetTitle(summarize(text))
-		err := sys.Tcsetpgrp(0, ev.Stub.Process().Pid)
+		dir, err := os.Getwd()
+		if err != nil {
+			dir = "/"
+		}
+		ev.Stub.Chdir(dir)
+		err = sys.Tcsetpgrp(0, ev.Stub.Process().Pid)
 		if err != nil {
 			fmt.Println("failed to put stub in foreground:", err)
 		}

stub/stub.go

@@ -96,7 +96,12 @@ func (stub *Stub) Terminate() {
 
 // SetTitle sets the title of the stub.
 func (stub *Stub) SetTitle(s string) {
-	stub.write.WriteString(s + "\n")
+	s = strings.TrimSpace(s)
+	fmt.Fprintf(stub.write, "t %d %s\n", len(s), s)
+}
+
+func (stub *Stub) Chdir(dir string) {
+	fmt.Fprintf(stub.write, "d %d %s\n", len(dir), dir)
 }
 
 // Signals returns a channel into which signals sent to the stub are relayed.

stubimpl/main.c

@@ -22,9 +22,7 @@ void handler(int signum) {
     must(write(1, p, s+4-p) != -1, "write signum");
 }
 
-enum { ARGV0BUF = 32 };
-
-char argv0buf[ARGV0BUF];
+enum { ARGV0MAX = 32 };
 
 int main(int argc, char **argv) {
     int i;
@@ -36,18 +34,28 @@ int main(int argc, char **argv) {
 
     must(write(1, "ok\n", 3) != -1, "write ok");
 
-    while (1) {
-        if (fgets(argv0buf, ARGV0BUF, stdin) == NULL) {
-            if (feof(stdin)) {
-                exit(0);
-            } else {
-                exit(10);
+    char op;
+    int len;
+    char *buf;
+    int scanned;
+    while ((scanned = scanf(" %c%d ", &op, &len)) == 2) {
+        printf("op=%d, len=%d\n", op, len);
+        buf = malloc(len+1);
+        fgets(buf, len+1, stdin);
+        printf("buf=%s\n", buf);
+        if (op == 'd') {
+            // Change directory.
+            chdir(buf);
+        } else if (op == 't') {
+            if (len > ARGV0MAX) {
+                buf[ARGV0MAX] = '\0';
             }
+            strcpy(argv[0], buf);
         }
-        int n = strlen(argv0buf);
-        if (n > 0 && argv0buf[n-1] == '\n') {
-            argv0buf[n-1] = '\0';
-        }
-        strcpy(argv[0], argv0buf);
+        free(buf);
     }
+    if (scanned != EOF) {
+        return 1;
+    }
+    return 0;
 }