1 /*
2 * Copyright (c) 2016, 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 package jdk.jshell.execution;
26
27 import jdk.jshell.spi.ExecutionEnv;
28
29 import java.io.IOException;
30 import java.io.InputStream;
31 import java.io.ObjectInput;
32 import java.io.ObjectInputStream;
33 import java.io.ObjectOutput;
34 import java.io.ObjectOutputStream;
35 import java.io.OutputStream;
36 import java.util.Arrays;
37 import java.util.HashMap;
38 import java.util.Map;
39 import java.util.Map.Entry;
40 import java.util.function.BiFunction;
41 import java.util.function.Consumer;
42
43 import com.sun.jdi.VirtualMachine;
44 import jdk.jshell.spi.ExecutionControl;
45
46
47 /**
48 * Miscellaneous utility methods for setting-up implementations of
49 * {@link ExecutionControl}. Particularly implementations with remote
50 * execution.
51 *
52 * @author Jan Lahoda
53 * @author Robert Field
54 */
55 public class Util {
56
57 // never instanciated
58 private Util() {}
59
60 /**
61 * Create a composite {@link ExecutionControl.Generator} instance that, when
62 * generating, will try each specified generator until successfully creating
63 * an {@link ExecutionControl} instance, or, if all fail, will re-throw the
64 * first exception.
65 *
66 * @param gec0 the first instance to try
67 * @param gecs the second through Nth instance to try
68 * @return the fail-over generator
69 */
70 public static ExecutionControl.Generator failOverExecutionControlGenerator(
71 ExecutionControl.Generator gec0, ExecutionControl.Generator... gecs) {
72 return (ExecutionEnv env) -> {
73 Throwable thrown;
74 try {
75 return gec0.generate(env);
76 } catch (Throwable ex) {
77 thrown = ex;
78 }
79 for (ExecutionControl.Generator gec : gecs) {
80 try {
81 return gec.generate(env);
82 } catch (Throwable ignore) {
83 // only care about the first, and only if they all fail
84 }
85 }
86 throw thrown;
87 };
88 }
89
90 /**
91 * Forward commands from the input to the specified {@link ExecutionControl}
92 * instance, then responses back on the output.
93 * @param ec the direct instance of {@link ExecutionControl} to process commands
94 * @param in the command input
95 * @param out the command response output
96 */
97 public static void forwardExecutionControl(ExecutionControl ec,
98 ObjectInput in, ObjectOutput out) {
99 new ExecutionControlForwarder(ec, in, out).commandLoop();
100 }
101
102 /**
103 * Forward commands from the input to the specified {@link ExecutionControl}
104 * instance, then responses back on the output.
105 * @param ec the direct instance of {@link ExecutionControl} to process commands
106 * @param inStream the stream from which to create the command input
107 * @param outStream the stream that will carry any specified auxiliary channels (like
108 * {@code System.out} and {@code System.err}), and the command response output.
109 * @param outputStreamMap a map between names of additional streams to carry and setters
110 * for the stream. Names starting with '$' are reserved for internal use.
111 * @param inputStreamMap a map between names of additional streams to carry and setters
112 * for the stream. Names starting with '$' are reserved for internal use.
113 * @throws IOException if there are errors using the passed streams
114 */
115 public static void forwardExecutionControlAndIO(ExecutionControl ec,
116 InputStream inStream, OutputStream outStream,
117 Map<String, Consumer<OutputStream>> outputStreamMap,
118 Map<String, Consumer<InputStream>> inputStreamMap) throws IOException {
119 for (Entry<String, Consumer<OutputStream>> e : outputStreamMap.entrySet()) {
120 e.getValue().accept(multiplexingOutputStream(e.getKey(), outStream));
121 }
122
123 ObjectOutputStream cmdOut = new ObjectOutputStream(multiplexingOutputStream("$command", outStream));
124 PipeInputStream cmdInPipe = new PipeInputStream();
125 Map<String, OutputStream> inputs = new HashMap<>();
126 inputs.put("$command", cmdInPipe.createOutput());
127 for (Entry<String, Consumer<InputStream>> e : inputStreamMap.entrySet()) {
128 OutputStream inputSignal = multiplexingOutputStream("$" + e.getKey() + "-input-requested", outStream);
129 PipeInputStream inputPipe = new PipeInputStream() {
130 @Override protected void inputNeeded() throws IOException {
131 inputSignal.write('1');
132 inputSignal.flush();
133 }
134 };
135 inputs.put(e.getKey(), inputPipe.createOutput());
136 e.getValue().accept(inputPipe);
137 }
138 new DemultiplexInput(inStream, inputs, inputs.values()).start();
139 ObjectInputStream cmdIn = new ObjectInputStream(cmdInPipe);
140
141 forwardExecutionControl(ec, cmdIn, cmdOut);
142 }
143
144 static OutputStream multiplexingOutputStream(String label, OutputStream outputStream) {
145 return new MultiplexingOutputStream(label, outputStream);
146 }
147
148 /**
149 * Creates an ExecutionControl for given packetized input and output. The given InputStream
150 * is de-packetized, and content forwarded to ObjectInput and given OutputStreams. The ObjectOutput
151 * and values read from the given InputStream are packetized and sent to the given OutputStream.
152 *
153 * @param input the packetized input stream
154 * @param output the packetized output stream
155 * @param outputStreamMap a map between stream names and the output streams to forward.
156 * Names starting with '$' are reserved for internal use.
157 * @param inputStreamMap a map between stream names and the input streams to forward.
158 * Names starting with '$' are reserved for internal use.
159 * @param factory to create the ExecutionControl from ObjectInput and ObjectOutput.
160 * @return the created ExecutionControl
161 * @throws IOException if setting up the streams raised an exception
162 */
163 public static ExecutionControl remoteInputOutput(InputStream input, OutputStream output,
164 Map<String, OutputStream> outputStreamMap, Map<String, InputStream> inputStreamMap,
165 BiFunction<ObjectInput, ObjectOutput, ExecutionControl> factory) throws IOException {
166 Map<String, OutputStream> augmentedStreamMap = new HashMap<>(outputStreamMap);
167 ObjectOutput commandOut = new ObjectOutputStream(Util.multiplexingOutputStream("$command", output));
168 for (Entry<String, InputStream> e : inputStreamMap.entrySet()) {
169 InputStream in = e.getValue();
170 OutputStream inTarget = Util.multiplexingOutputStream(e.getKey(), output);
171 augmentedStreamMap.put("$" + e.getKey() + "-input-requested", new OutputStream() {
172 @Override
173 public void write(int b) throws IOException {
174 //value ignored, just a trigger to read from the input
175 inTarget.write(in.read());
176 }
177 });
178 }
179 PipeInputStream commandIn = new PipeInputStream();
180 OutputStream commandInTarget = commandIn.createOutput();
181 augmentedStreamMap.put("$command", commandInTarget);
182 new DemultiplexInput(input, augmentedStreamMap, Arrays.asList(commandInTarget)).start();
183 return factory.apply(new ObjectInputStream(commandIn), commandOut);
184 }
185
186 /**
187 * Monitor the JDI event stream for {@link com.sun.jdi.event.VMDeathEvent}
188 * and {@link com.sun.jdi.event.VMDisconnectEvent}. If encountered, invokes
189 * {@code unbiddenExitHandler}.
190 *
191 * @param vm the virtual machine to check
192 * @param unbiddenExitHandler the handler, which will accept the exit
193 * information
194 */
195 public static void detectJDIExitEvent(VirtualMachine vm, Consumer<String> unbiddenExitHandler) {
196 if (vm.canBeModified()) {
197 new JDIEventHandler(vm, unbiddenExitHandler).start();
198 }
199 }
200
201 }