8187443: Forest Consolidation: Move files to unified layout

Reviewed-by: darcy, ihse

src/java.base/share/classes/java/io/DeleteOnExitHook.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2005, 2010, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.
+ */
+package java.io;
+
+import java.util.*;
+import java.io.File;
+import jdk.internal.misc.SharedSecrets;
+
+/**
+ * This class holds a set of filenames to be deleted on VM exit through a shutdown hook.
+ * A set is used both to prevent double-insertion of the same file as well as offer
+ * quick removal.
+ */
+
+class DeleteOnExitHook {
+    private static LinkedHashSet<String> files = new LinkedHashSet<>();
+    static {
+        // DeleteOnExitHook must be the last shutdown hook to be invoked.
+        // Application shutdown hooks may add the first file to the
+        // delete on exit list and cause the DeleteOnExitHook to be
+        // registered during shutdown in progress. So set the
+        // registerShutdownInProgress parameter to true.
+        SharedSecrets.getJavaLangAccess()
+            .registerShutdownHook(2 /* Shutdown hook invocation order */,
+                true /* register even if shutdown in progress */,
+                new Runnable() {
+                    public void run() {
+                       runHooks();
+                    }
+                }
+        );
+    }
+
+    private DeleteOnExitHook() {}
+
+    static synchronized void add(String file) {
+        if(files == null) {
+            // DeleteOnExitHook is running. Too late to add a file
+            throw new IllegalStateException("Shutdown in progress");
+        }
+
+        files.add(file);
+    }
+
+    static void runHooks() {
+        LinkedHashSet<String> theFiles;
+
+        synchronized (DeleteOnExitHook.class) {
+            theFiles = files;
+            files = null;
+        }
+
+        ArrayList<String> toBeDeleted = new ArrayList<>(theFiles);
+
+        // reverse the list to maintain previous jdk deletion order.
+        // Last in first deleted.
+        Collections.reverse(toBeDeleted);
+        for (String filename : toBeDeleted) {
+            (new File(filename)).delete();
+        }
+    }
+}