--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/src/share/classes/jdk/jfr/internal/dcmd/AbstractDCmd.java	2019-01-29 10:59:56.337067440 +0800
@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2012, 2019, 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 jdk.jfr.internal.dcmd;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Path;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import jdk.jfr.FlightRecorder;
+import jdk.jfr.Recording;
+import jdk.jfr.internal.SecuritySupport;
+import jdk.jfr.internal.SecuritySupport.SafePath;
+import jdk.jfr.internal.Utils;
+
+/**
+ * Base class for JFR diagnostic commands
+ *
+ */
+abstract class AbstractDCmd {
+
+    private final StringWriter result;
+    private final PrintWriter log;
+
+    protected AbstractDCmd() {
+        result = new StringWriter();
+        log = new PrintWriter(result);
+    }
+
+    protected final FlightRecorder getFlightRecorder() {
+        return FlightRecorder.getFlightRecorder();
+    }
+
+    public final String getResult() {
+        return result.toString();
+    }
+
+    protected final SafePath resolvePath(String path, String errorMsg) throws DCmdException {
+        if (path == null) {
+            return null;
+        }
+        try {
+            return new SafePath(path);
+        } catch (InvalidPathException e) {
+            throw new DCmdException(e, errorMsg, ", invalid path \"" + path + "\".");
+        }
+    }
+
+    protected final Recording findRecording(String name) throws DCmdException {
+        try {
+            return findRecordingById(Integer.parseInt(name));
+        } catch (NumberFormatException nfe) {
+            // User specified a name, not an id.
+            return findRecordingByName(name);
+        }
+    }
+
+    protected final void reportOperationComplete(String actionPrefix, Recording r, SafePath file) {
+        print(actionPrefix);
+        print(" recording ");
+        print("\"" + r.getName() + "\"");
+        if (file != null) {
+            print(",");
+            try {
+                print(" ");
+                long bytes = SecuritySupport.getFileSize(file);
+                printBytes(bytes, " ");
+            } catch (IOException e) {
+                // Ignore, not essential
+            }
+            println(" written to:");
+            println();
+            printPath(file);
+        } else {
+            println(".");
+        }
+    }
+
+    protected final List<Recording> getRecordings() {
+        List<Recording> list = new ArrayList<>(getFlightRecorder().getRecordings());
+        Collections.sort(list, (a, b) -> a.getName().compareTo(b.getName()));
+        return list;
+    }
+
+    static String quoteIfNeeded(String text) {
+        if (text.contains(" ")) {
+            return "\\\"" + text + "\\\"";
+        } else {
+            return text;
+        }
+    }
+
+    protected final void println() {
+        log.println();
+    }
+
+    protected final void print(String s) {
+        log.print(s);
+    }
+
+    protected final void print(String s, Object... args) {
+        log.printf(s, args);
+    }
+
+    protected final void println(String s, Object... args) {
+        print(s, args);
+        println();
+    }
+
+    protected final void printBytes(long bytes, String separation) {
+       print(Utils.formatBytes(bytes, separation));
+    }
+
+    protected final void printTimespan(Duration timespan, String separator) {
+        print(Utils.formatTimespan(timespan, separator));
+    }
+
+    protected final void printPath(SafePath path) {
+        if (path == null) {
+            print("N/A");
+            return;
+        }
+        try {
+            printPath(SecuritySupport.getAbsolutePath(path).toPath());
+        } catch (IOException ioe) {
+            printPath(path.toPath());
+        }
+    }
+
+    protected final void printPath(Path path) {
+        try {
+            println(path.toAbsolutePath().toString());
+        } catch (SecurityException e) {
+            // fall back on filename
+            println(path.toString());
+        }
+    }
+
+    private Recording findRecordingById(int id) throws DCmdException {
+        for (Recording r : getFlightRecorder().getRecordings()) {
+            if (r.getId() == id) {
+                return r;
+            }
+        }
+        throw new DCmdException("Could not find %d.\n\nUse JFR.check without options to see list of all available recordings.", id);
+    }
+
+    private Recording findRecordingByName(String name) throws DCmdException {
+        for (Recording recording : getFlightRecorder().getRecordings()) {
+            if (name.equals(recording.getName())) {
+                return recording;
+            }
+        }
+        throw new DCmdException("Could not find %s.\n\nUse JFR.check without options to see list of all available recordings.", name);
+    }
+}