Issue #287 - Introduce Tycho Pomless Build and Maven Wrapper

This change gets rid of most pom.xml files in Corrosion. This is done
by using the Tycho Pomless technology in it's latest version. Since
Tycho Pomless is somehow sensitive to different maven versions, the
maven wrapper technology is used. This allows users (even without a
maven installation) to always use the recommended maven version to build
Corrosion. Build instructions were updated accordingly.

The maven wrapper technology was approved via CQ 21342:
https://dev.eclipse.org/ipzilla/show_bug.cgi?id=21342

The added rustup-init.sh file was previously downloaded as part of the
build and was already approved via CQ 21017:
https://dev.eclipse.org/ipzilla/show_bug.cgi?id=21017

Signed-off-by: Max Bureck <max.bureck@fokus.fraunhofer.de>

.mvn/extensions.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<extensions>
+  <extension>
+    <groupId>org.eclipse.tycho.extras</groupId>
+    <artifactId>tycho-pomless</artifactId>
+    <version>1.5.1</version>
+  </extension>
+</extensions>

.mvn/wrapper/MavenWrapperDownloader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2007-present 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.
+ */
+import java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,2 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar

CONTRIBUTING.md

@@ -7,7 +7,9 @@ Issue reports and feature requests are always appreciated and are made in the [I
 
 ### Building locally
 
-Local build happens with a simple `mvn clean verify`. Main build output is a p2 repository that you can find in `repository/target/repository`. You can use it to install and test the built artifacts in a working Eclipse IDE.
+Local build happens with a simple `mvnw clean verify`. Main build output is a p2 repository that you can find in `repository/target/repository`. You can use it to install and test the built artifacts in a working Eclipse IDE. 
+
+Note that on windows the command cannot be invoked from PowerShell, but only from CMD.
 
 ### Modify Corrosion in the Eclipse IDE
 

Jenkinsfile

@@ -7,7 +7,6 @@ pipeline {
 		PATH = "$HOME/.cargo/bin/:$PATH"
 	}
 	tools {
-        maven 'apache-maven-latest'
         jdk 'jdk1.8.0-latest'
     }
 	stages {
@@ -27,7 +26,7 @@ pipeline {
 				sh 'cargo --version'
 				sh 'rustup show'
 				wrap([$class: 'Xvnc', useXauthority: true]) {
-					sh 'mvn -Dmaven.repo.local=$WORKSPACE/.m2 clean verify -Dmaven.test.error.ignore=true -Dmaven.test.failure.ignore=true -PpackAndSign'
+					sh './mvnw -Dmaven.repo.local=$WORKSPACE/.m2 clean verify -Dmaven.test.error.ignore=true -Dmaven.test.failure.ignore=true -PpackAndSign'
 				}
 			}
 			post {

NOTICE.md

@@ -55,6 +55,9 @@ Rustup (Workswith)
 Rust and Cargo logos
 * License: [CC-BY-4.0](https://www.rust-lang.org/en-US/legal.html)
 
+[Maven Wrapper (Build Time)](https://github.com/takari/maven-wrapper/tree/maven-wrapper-0.5.6)
+* License: [Apache-2.0](https://github.com/takari/maven-wrapper/blob/maven-wrapper-0.5.6/LICENSE.txt)
+
 ## Cryptography
 
 Content may contain encryption software. The country in which you are currently