| 1 | /******************************************************************************* |
| 2 | * Copyright (c) 2016 EfficiOS Inc., Alexandre Montplaisir |
| 3 | * |
| 4 | * All rights reserved. This program and the accompanying materials |
| 5 | * are made available under the terms of the Eclipse Public License v1.0 |
| 6 | * which accompanies this distribution, and is available at |
| 7 | * http://www.eclipse.org/legal/epl-v10.html |
| 8 | *******************************************************************************/ |
| 9 | |
| 10 | package org.eclipse.tracecompass.common.core.process; |
| 11 | |
| 12 | import static org.eclipse.tracecompass.common.core.NonNullUtils.checkNotNull; |
| 13 | |
| 14 | import java.io.BufferedReader; |
| 15 | import java.io.IOException; |
| 16 | import java.io.InputStreamReader; |
| 17 | import java.util.LinkedList; |
| 18 | import java.util.List; |
| 19 | import java.util.stream.Collectors; |
| 20 | |
| 21 | import org.eclipse.core.runtime.CoreException; |
| 22 | import org.eclipse.core.runtime.IProgressMonitor; |
| 23 | import org.eclipse.core.runtime.IStatus; |
| 24 | import org.eclipse.core.runtime.MultiStatus; |
| 25 | import org.eclipse.core.runtime.Status; |
| 26 | import org.eclipse.jdt.annotation.Nullable; |
| 27 | import org.eclipse.tracecompass.internal.common.core.Activator; |
| 28 | |
| 29 | /** |
| 30 | * Common utility methods for launching external processes and retrieving their |
| 31 | * output. |
| 32 | * |
| 33 | * @author Alexandre Montplaisir |
| 34 | * @since 2.2 |
| 35 | */ |
| 36 | public final class ProcessUtils { |
| 37 | |
| 38 | private ProcessUtils() {} |
| 39 | |
| 40 | /** |
| 41 | * Simple output-getting command. Cannot be cancelled, and will return null |
| 42 | * if the external process exits with a non-zero return code. |
| 43 | * |
| 44 | * @param command |
| 45 | * The command (executable + arguments) to launch |
| 46 | * @return The process's standard output upon completion |
| 47 | */ |
| 48 | public static @Nullable List<String> getOutputFromCommand(List<String> command) { |
| 49 | try { |
| 50 | ProcessBuilder builder = new ProcessBuilder(command); |
| 51 | builder.redirectErrorStream(true); |
| 52 | |
| 53 | Process p = builder.start(); |
| 54 | try (BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));) { |
| 55 | List<String> output = new LinkedList<>(); |
| 56 | |
| 57 | /* |
| 58 | * We must consume the output before calling Process.waitFor(), |
| 59 | * or else the buffers might fill and block the external program |
| 60 | * if there is a lot of output. |
| 61 | */ |
| 62 | String line = br.readLine(); |
| 63 | while (line != null) { |
| 64 | output.add(line); |
| 65 | line = br.readLine(); |
| 66 | } |
| 67 | |
| 68 | int ret = p.waitFor(); |
| 69 | return (ret == 0 ? output : null); |
| 70 | } |
| 71 | } catch (IOException | InterruptedException e) { |
| 72 | return null; |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | /** |
| 77 | * Interface defining what do to with a process's output. For use with |
| 78 | * {@link #getOutputFromCommandCancellable}. |
| 79 | */ |
| 80 | @FunctionalInterface |
| 81 | public static interface OutputReaderFunction { |
| 82 | |
| 83 | /** |
| 84 | * Handle the output of the process. This can include reporting progress |
| 85 | * to the monitor, and pre-processing the returned output. |
| 86 | * |
| 87 | * @param reader |
| 88 | * A buffered reader to the process's standard output. |
| 89 | * Managed internally, so you do not need to |
| 90 | * {@link BufferedReader#close()} it. |
| 91 | * @param monitor |
| 92 | * The progress monitor. Implementation should check |
| 93 | * periodically if it is cancelled to end processing early. |
| 94 | * The monitor's start and end will be managed, but progress |
| 95 | * can be reported via the {@link IProgressMonitor#worked} |
| 96 | * method. The total is 1000 work units. |
| 97 | * @return The process's output |
| 98 | * @throws IOException |
| 99 | * If there was a read error. Letting throw all exception |
| 100 | * from the {@link BufferedReader} is recommended. |
| 101 | */ |
| 102 | List<String> readOutput(BufferedReader reader, IProgressMonitor monitor) throws IOException; |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Cancellable output-getting command. The processing, as well as the |
| 107 | * external process itself, can be stopped by cancelling the passed progress |
| 108 | * monitor. |
| 109 | * |
| 110 | * @param command |
| 111 | * The command (executable + arguments) to execute |
| 112 | * @param monitor |
| 113 | * The progress monitor to check for cancellation and optionally |
| 114 | * progress |
| 115 | * @param mainTaskName |
| 116 | * The main task name of the job |
| 117 | * @param readerFunction |
| 118 | * What to do with the output. See {@link OutputReaderFunction}. |
| 119 | * @return The process's standard output, upon normal completion |
| 120 | * @throws CoreException |
| 121 | * If a problem happened with the execution of the external |
| 122 | * process. It can be reported to the user with the help of an |
| 123 | * ErrorDialog. |
| 124 | */ |
| 125 | public static List<String> getOutputFromCommandCancellable(List<String> command, |
| 126 | IProgressMonitor monitor, |
| 127 | String mainTaskName, |
| 128 | OutputReaderFunction readerFunction) |
| 129 | throws CoreException { |
| 130 | |
| 131 | CancellableRunnable cancellerRunnable = null; |
| 132 | Thread cancellerThread = null; |
| 133 | |
| 134 | try { |
| 135 | monitor.beginTask(mainTaskName, 1000); |
| 136 | |
| 137 | ProcessBuilder builder = new ProcessBuilder(command); |
| 138 | builder.redirectErrorStream(false); |
| 139 | |
| 140 | Process p = checkNotNull(builder.start()); |
| 141 | |
| 142 | cancellerRunnable = new CancellableRunnable(p, monitor); |
| 143 | cancellerThread = new Thread(cancellerRunnable); |
| 144 | cancellerThread.start(); |
| 145 | |
| 146 | try (BufferedReader stdoutReader = new BufferedReader(new InputStreamReader(p.getInputStream()));) { |
| 147 | |
| 148 | List<String> lines = readerFunction.readOutput(stdoutReader, monitor); |
| 149 | |
| 150 | int ret = p.waitFor(); |
| 151 | |
| 152 | if (monitor.isCanceled()) { |
| 153 | /* We were interrupted by the canceller thread. */ |
| 154 | IStatus status = new Status(IStatus.CANCEL, Activator.instance().getPluginId(), null); |
| 155 | throw new CoreException(status); |
| 156 | } |
| 157 | |
| 158 | if (ret != 0) { |
| 159 | /* |
| 160 | * Something went wrong running the external process. We |
| 161 | * will gather the stderr and report it to the user. |
| 162 | */ |
| 163 | BufferedReader stderrReader = new BufferedReader(new InputStreamReader(p.getErrorStream())); |
| 164 | List<String> stderrOutput = stderrReader.lines().collect(Collectors.toList()); |
| 165 | |
| 166 | MultiStatus status = new MultiStatus(Activator.instance().getPluginId(), |
| 167 | IStatus.ERROR, Messages.ProcessUtils_ErrorDuringExecution, null); |
| 168 | for (String str : stderrOutput) { |
| 169 | status.add(new Status(IStatus.ERROR, Activator.instance().getPluginId(), str)); |
| 170 | } |
| 171 | if (stderrOutput.isEmpty()) { |
| 172 | /* |
| 173 | * At least say "no output", so an error message actually |
| 174 | * shows up. |
| 175 | */ |
| 176 | status.add(new Status(IStatus.ERROR, Activator.instance().getPluginId(), Messages.ProcessUtils_ErrorNoOutput)); |
| 177 | } |
| 178 | throw new CoreException(status); |
| 179 | } |
| 180 | |
| 181 | return lines; |
| 182 | } |
| 183 | |
| 184 | } catch (IOException | InterruptedException e) { |
| 185 | IStatus status = new Status(IStatus.ERROR, Activator.instance().getPluginId(), Messages.ProcessUtils_ExecutionInterrupted, e); |
| 186 | throw new CoreException(status); |
| 187 | |
| 188 | } finally { |
| 189 | if (cancellerRunnable != null) { |
| 190 | cancellerRunnable.setFinished(); |
| 191 | } |
| 192 | if (cancellerThread != null) { |
| 193 | try { |
| 194 | cancellerThread.join(); |
| 195 | } catch (InterruptedException e) { |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | monitor.done(); |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | /** |
| 204 | * Internal wrapper class that allows forcibly stopping a {@link Process} |
| 205 | * when its corresponding progress monitor is cancelled. |
| 206 | */ |
| 207 | private static class CancellableRunnable implements Runnable { |
| 208 | |
| 209 | private final Process fProcess; |
| 210 | private final IProgressMonitor fMonitor; |
| 211 | |
| 212 | private boolean fIsFinished = false; |
| 213 | |
| 214 | public CancellableRunnable(Process process, IProgressMonitor monitor) { |
| 215 | fProcess = process; |
| 216 | fMonitor = monitor; |
| 217 | } |
| 218 | |
| 219 | public void setFinished() { |
| 220 | fIsFinished = true; |
| 221 | } |
| 222 | |
| 223 | @Override |
| 224 | public void run() { |
| 225 | try { |
| 226 | while (!fIsFinished) { |
| 227 | Thread.sleep(500); |
| 228 | if (fMonitor.isCanceled()) { |
| 229 | fProcess.destroy(); |
| 230 | return; |
| 231 | } |
| 232 | } |
| 233 | } catch (InterruptedException e) { |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | } |
| 238 | } |