1 /*

     2  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package jdk.internal.jshell.tool;

    27 

    28 import java.io.IOException;

    29 import java.nio.charset.Charset;

    30 import java.nio.file.ClosedWatchServiceException;

    31 import java.nio.file.FileSystems;

    32 import java.nio.file.Files;

    33 import java.nio.file.Path;

    34 import java.nio.file.WatchKey;

    35 import java.nio.file.WatchService;

    36 import java.util.Arrays;

    37 import java.util.Scanner;

    38 import java.util.function.Consumer;

    39 import java.util.stream.Collectors;

    40 import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;

    41 import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;

    42 import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;

    43 

    44 /**

    45  * Wrapper for controlling an external editor.

    46  */

    47 public class ExternalEditor {

    48     private final Consumer<String> errorHandler;

    49     private final Consumer<String> saveHandler;

    50     private final Consumer<String> printHandler;

    51     private final IOContext input;

    52     private final boolean wait;

    53 

    54     private WatchService watcher;

    55     private Thread watchedThread;

    56     private Path dir;

    57     private Path tmpfile;

    58 

    59     ExternalEditor(Consumer<String> errorHandler, Consumer<String> saveHandler,

    60             IOContext input, boolean wait, Consumer<String> printHandler) {

    61         this.errorHandler = errorHandler;

    62         this.saveHandler = saveHandler;

    63         this.printHandler = printHandler;

    64         this.input = input;

    65         this.wait = wait;

    66     }

    67 

    68     private void edit(String[] cmd, String initialText) {

    69         try {

    70             setupWatch(initialText);

    71             launch(cmd);

    72         } catch (IOException ex) {

    73             errorHandler.accept(ex.getMessage());

    74         }

    75     }

    76 

    77     /**

    78      * Creates a WatchService and registers the given directory

    79      */

    80     private void setupWatch(String initialText) throws IOException {

    81         this.watcher = FileSystems.getDefault().newWatchService();

    82         this.dir = Files.createTempDirectory("jshelltemp");

    83         this.tmpfile = Files.createTempFile(dir, null, ".java");

    84         Files.write(tmpfile, initialText.getBytes(Charset.forName("UTF-8")));

    85         dir.register(watcher,

    86                 ENTRY_CREATE,

    87                 ENTRY_DELETE,

    88                 ENTRY_MODIFY);

    89         watchedThread = new Thread(() -> {

    90             for (;;) {

    91                 WatchKey key;

    92                 try {

    93                     key = watcher.take();

    94                 } catch (ClosedWatchServiceException ex) {

    95                     // The watch service has been closed, we are done

    96                     break;

    97                 } catch (InterruptedException ex) {

    98                     // tolerate an interrupt

    99                     continue;

   100                 }

   101 

   102                 if (!key.pollEvents().isEmpty()) {

   103                     // Changes have occurred in temp edit directory,

   104                     // transfer the new sources to JShell (unless the editor is

   105                     // running directly in JShell's window -- don't make a mess)

   106                     if (!input.terminalEditorRunning()) {

   107                         saveFile();

   108                     }

   109                 }

   110 

   111                 boolean valid = key.reset();

   112                 if (!valid) {

   113                     // The watch service has been closed, we are done

   114                     break;

   115                 }

   116             }

   117         });

   118         watchedThread.start();

   119     }

   120 

   121     private void launch(String[] cmd) throws IOException {

   122         String[] params = Arrays.copyOf(cmd, cmd.length + 1);

   123         params[cmd.length] = tmpfile.toString();

   124         ProcessBuilder pb = new ProcessBuilder(params);

   125         pb = pb.inheritIO();

   126 

   127         try {

   128             input.suspend();

   129             Process process = pb.start();

   130             // wait to exit edit mode in one of these ways...

   131             if (wait) {

   132                 // -wait option -- ignore process exit, wait for carriage-return

   133                 Scanner scanner = new Scanner(System.in);

   134                 printHandler.accept("jshell.msg.press.return.to.leave.edit.mode");

   135                 scanner.nextLine();

   136             } else {

   137                 // wait for process to exit

   138                 process.waitFor();

   139             }

   140         } catch (IOException ex) {

   141             errorHandler.accept("process IO failure: " + ex.getMessage());

   142         } catch (InterruptedException ex) {

   143             errorHandler.accept("process interrupt: " + ex.getMessage());

   144         } finally {

   145             try {

   146                 watcher.close();

   147                 watchedThread.join(); //so that saveFile() is finished.

   148                 saveFile();

   149             } catch (InterruptedException ex) {

   150                 errorHandler.accept("process interrupt: " + ex.getMessage());

   151             } finally {

   152                 input.resume();

   153             }

   154         }

   155     }

   156 

   157     private void saveFile() {

   158         try {

   159             saveHandler.accept(Files.lines(tmpfile).collect(Collectors.joining("\n", "", "\n")));

   160         } catch (IOException ex) {

   161             errorHandler.accept("Failure in read edit file: " + ex.getMessage());

   162         }

   163     }

   164 

   165     static void edit(String[] cmd, Consumer<String> errorHandler, String initialText,

   166             Consumer<String> saveHandler, IOContext input, boolean wait, Consumer<String> printHandler) {

   167         ExternalEditor ed = new ExternalEditor(errorHandler, saveHandler, input, wait, printHandler);

   168         ed.edit(cmd, initialText);

   169     }

   170 }