Add nativeimage API for per-thread recurring callbacks using the safe…

…point mechanism

sdk/src/org.graalvm.nativeimage/src/org/graalvm/nativeimage/Threading.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2017, 2017, 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 org.graalvm.nativeimage;
+
+import java.util.concurrent.TimeUnit;
+
+import org.graalvm.nativeimage.impl.ThreadingSupport;
+
+/**
+ * Functionality related to execution in threads.
+ */
+public final class Threading {
+    /**
+     * Registers a callback handler that is called by the current thread approximately at the
+     * provided interval. Only one callback can be active per thread. Every thread can have its own
+     * (or no) callback with a different interval. No guarantees are made about the actual interval.
+     * For example, when the thread is waiting for a lock or executing native code, no callback can
+     * be done. Specifying {@code null} for the callback clears the thread's current callback (in
+     * this case, the values of {@code interval} and {@code unit} are ignored).
+     */
+    public static void registerRecurringCallback(long interval, TimeUnit unit, Runnable callback) {
+        ImageSingletons.lookup(ThreadingSupport.class).registerRecurringCallback(interval, unit, callback);
+    }
+}

sdk/src/org.graalvm.nativeimage/src/org/graalvm/nativeimage/impl/ThreadingSupport.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2017, 2017, 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 org.graalvm.nativeimage.impl;
+
+import java.util.concurrent.TimeUnit;
+
+public interface ThreadingSupport {
+    void registerRecurringCallback(long interval, TimeUnit unit, Runnable callback);
+}