protext exps during rniEval for safety

Author: s-u

src/jri/Rengine.java

@@ -548,7 +548,16 @@ public synchronized REXP eval(String s, boolean convert) {
             if (pr != 0) {
                 long er = rniEval(pr, 0);
                 if (er != 0) {
-                    REXP x = new REXP(this, er, convert);
+		    REXP x;
+		    if (convert) {
+			rniProtect(er);
+			try {
+			    x = new REXP(this, er, convert);
+			} finally {
+			    rniUnprotect(1);
+			}
+		    } else
+			x = new REXP(this, er, convert);
                     if (DEBUG>0) System.out.println("Rengine.eval("+s+"): END (OK)"+Thread.currentThread());
                     return x;
                 }

src/jri/src/Rengine.c

@@ -156,19 +156,24 @@ JNIEXPORT jlong JNICALL Java_org_rosuda_JRI_Rengine_rniEval
       /* invalid (NULL) expression (parse error, ... ) */
       if (!exp) return 0;
 
+      PROTECT(exps);
       if (TYPEOF(exps) == EXPRSXP) { 
       	  /* if the object is a list of exps, eval them one by one */
           l = LENGTH(exps);
           while (i < l) {
               es = R_tryEval(VECTOR_ELT(exps,i), eval_env, &er);
 
               /* an error occured, no need to continue */
-              if (er) return 0;
+              if (er) {
+		  UNPROTECT(1);
+		  return 0;
+	      }
               i++;
           }
       } else
           es = R_tryEval(exps, eval_env, &er);
-      
+      UNPROTECT(1);
+
       /* er is just a flag - on error return 0 */
       if (er) return 0;