8013528: Provide SharedSecrets access to String(char[], boolean) constructor
Reviewed-by: martin, alanb, chegar, plevart
--- a/jdk/src/share/classes/java/lang/System.java Thu May 02 13:21:09 2013 +0200
+++ b/jdk/src/share/classes/java/lang/System.java Fri May 03 10:57:28 2013 -0700
@@ -1246,6 +1246,9 @@
public StackTraceElement getStackTraceElement(Throwable t, int i) {
return t.getStackTraceElement(i);
}
+ public String newStringUnsafe(char[] chars) {
+ return new String(chars, true);
+ }
});
}
}
--- a/jdk/src/share/classes/sun/misc/JavaLangAccess.java Thu May 02 13:21:09 2013 +0200
+++ b/jdk/src/share/classes/sun/misc/JavaLangAccess.java Fri May 03 10:57:28 2013 -0700
@@ -97,4 +97,14 @@
* Returns the ith StackTraceElement for the given throwable.
*/
StackTraceElement getStackTraceElement(Throwable t, int i);
+
+ /**
+ * Returns a new string backed by the provided character array. The
+ * character array is not copied and must never be modified after the
+ * String is created, in order to fulfill String's contract.
+ *
+ * @param chars the character array to back the string
+ * @return a newly created string whose content is the character array
+ */
+ String newStringUnsafe(char[] chars);
}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/sun/misc/JavaLangAccess/NewUnsafeString.java Fri May 03 10:57:28 2013 -0700
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+import java.util.Objects;
+import java.util.Comparators;
+import sun.misc.JavaLangAccess;
+import sun.misc.SharedSecrets;
+
+/*
+ * @test
+ * @summary Test JavaLangAccess.newUnsafeString
+ * @bug 8013528
+ * @compile -XDignore.symbol.file NewUnsafeString.java
+ */
+public class NewUnsafeString {
+
+ static final JavaLangAccess jla = SharedSecrets.getJavaLangAccess();
+
+ public static void testNewUnsafeString() {
+ String benchmark = "exemplar";
+ String constructorCopy = new String(benchmark);
+ char[] jlaChars = benchmark.toCharArray();
+ String jlaCopy = jla.newStringUnsafe(jlaChars);
+
+ if (benchmark == constructorCopy) {
+ throw new Error("should be different instances");
+ }
+ if (!benchmark.equals(constructorCopy)) {
+ throw new Error("Copy not equal");
+ }
+ if (0 != Objects.compare(benchmark, constructorCopy, Comparators.naturalOrder())) {
+ throw new Error("Copy not equal");
+ }
+
+ if (benchmark == jlaCopy) {
+ throw new Error("should be different instances");
+ }
+ if (!benchmark.equals(jlaCopy)) {
+ throw new Error("Copy not equal");
+ }
+ if (0 != Objects.compare(benchmark, jlaCopy, Comparators.naturalOrder())) {
+ throw new Error("Copy not equal");
+ }
+
+ if (constructorCopy == jlaCopy) {
+ throw new Error("should be different instances");
+ }
+ if (!constructorCopy.equals(jlaCopy)) {
+ throw new Error("Copy not equal");
+ }
+ if (0 != Objects.compare(constructorCopy, jlaCopy, Comparators.naturalOrder())) {
+ throw new Error("Copy not equal");
+ }
+
+ // The following is extremely "evil". Never ever do this in non-test code.
+ jlaChars[0] = 'X';
+ if (!"Xxemplar".equals(jlaCopy)) {
+ throw new Error("jla.newStringUnsafe did not use provided string");
+ }
+
+ }
+
+ public static void main(String[] args) {
+ testNewUnsafeString();
+ }
+}