Bash completion

client/pom.xml

@@ -95,6 +95,15 @@
                     </compilerArgs>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <configuration>
+                    <systemPropertyVariables>
+                        <project.basedir>${project.basedir}</project.basedir>
+                    </systemPropertyVariables>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 
@@ -124,6 +133,7 @@
                                 --no-fallback
                                 --allow-incomplete-classpath
                                 -H:IncludeResources=org/mvndaemon/mvnd/.*
+                                -H:IncludeResources=mvnd-bash-completion.bash
                                 -H:-ParseRuntimeOptions
                                 -ea
                             </buildArgs>

client/src/main/java/org/mvndaemon/mvnd/client/Completion.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.mvndaemon.mvnd.client;
+
+import org.mvndaemon.mvnd.common.IoUtils;
+
+public class Completion {
+
+    public static String getCompletion(String shell) {
+        if (!"bash".equals(shell)) {
+            throw new IllegalArgumentException("Unexpected --completion value: '" + shell + "'; expected: 'bash'");
+        }
+        return IoUtils.readResource(Completion.class.getClassLoader(), "mvnd-bash-completion.bash");
+    }
+
+}

client/src/main/java/org/mvndaemon/mvnd/client/DefaultClient.java

@@ -78,7 +78,8 @@ public static void main(String[] argv) throws Exception {
         }
 
         // Batch mode
-        boolean batchMode = Environment.MAVEN_BATCH_MODE.hasCommandLineOption(args);
+        boolean batchMode = Environment.MAVEN_BATCH_MODE.hasCommandLineOption(args)
+                || Environment.COMPLETION.hasCommandLineOption(args);
 
         // System properties
         setSystemPropertiesFromCommandLine(args);
@@ -133,6 +134,12 @@ public ExecutionResult execute(ClientOutput output, List<String> argv) {
         LOGGER.debug("Starting client");
 
         final List<String> args = new ArrayList<>(argv);
+        final String completionShell = Environment.COMPLETION.removeCommandLineOption(args);
+        if (completionShell != null) {
+            output.accept(Message.log(Completion.getCompletion(completionShell)));
+            return DefaultResult.success(argv);
+        }
+
         boolean version = Environment.MAVEN_VERSION.hasCommandLineOption(args);
         boolean showVersion = Environment.MAVEN_SHOW_VERSION.hasCommandLineOption(args);
         boolean debug = Environment.MAVEN_DEBUG.hasCommandLineOption(args);

client/src/test/java/org/mvndaemon/mvnd/client/CompletionGenerator.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.mvndaemon.mvnd.client;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Map;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.mvndaemon.mvnd.common.Environment;
+import org.mvndaemon.mvnd.common.Environment.OptionOrigin;
+import org.mvndaemon.mvnd.common.IoUtils;
+
+public class CompletionGenerator {
+
+    @Test
+    void generate() throws IOException {
+
+        String template = IoUtils.readResource(Completion.class.getClassLoader(),
+                "completion-templates/mvnd-bash-completion.bash");
+
+        final String shortOpts = Stream.of(Environment.values())
+                .filter(env -> !env.isInternal())
+                .flatMap(env -> env.getOptionMap().entrySet().stream())
+                .filter(optEntry -> optEntry.getValue() == OptionOrigin.mvnd)
+                .map(Map.Entry::getKey)
+                .filter(opt -> !opt.startsWith("--"))
+                .sorted()
+                .collect(Collectors.joining("|"));
+
+        final String longOpts = Stream.of(Environment.values())
+                .filter(env -> !env.isInternal())
+                .flatMap(env -> env.getOptionMap().entrySet().stream())
+                .filter(optEntry -> optEntry.getValue() == OptionOrigin.mvnd)
+                .map(Map.Entry::getKey)
+                .filter(opt -> opt.startsWith("--"))
+                .sorted()
+                .collect(Collectors.joining("|"));
+
+        final String props = Stream.of(Environment.values())
+                .filter(env -> !env.isInternal())
+                .map(Environment::getProperty)
+                .filter(Objects::nonNull)
+                .sorted()
+                .map(prop -> "-D" + prop)
+                .collect(Collectors.joining("|"));
+
+        template = template.replace("%mvnd_opts%", shortOpts);
+        template = template.replace("%mvnd_long_opts%", longOpts);
+        template = template.replace("%mvnd_properties%", props);
+
+        final Path baseDir = Paths.get(System.getProperty("project.basedir", "."));
+
+        final byte[] bytes = template.getBytes(StandardCharsets.UTF_8);
+        Files.write(baseDir.resolve("src/main/resources/mvnd-bash-completion.bash"), bytes);
+        Files.write(baseDir.resolve("target/classes/mvnd-bash-completion.bash"), bytes);
+
+    }
+
+}