New gradle task to build a distribution with downloaded JREs

Author: SimonC4

.gitignore

@@ -74,3 +74,6 @@ engine/src/main/resources/settings.ini
 engine/src/main/resources/mercenaries.json
 engine/src/main/resources/world.ini
 engine/src/main/resources/world.json
+
+# Ignore donwloaded JREs
+jre/**

config/gradle/jre.gradle

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2020 The Terasology Foundation
+ *
+ * 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.
+ */
+
+// Uses Bellsoft Liberica JRE
+def jreVersion = '8u212'
+def jreUrlBase = "https://download.bell-sw.com/java/$jreVersion/bellsoft-jre$jreVersion"
+def jreUrlFilenames = [
+        lwjreLinux64 : 'linux-amd64.tar.gz',
+        lwjreLinux   : 'linux-i586.tar.gz',
+        lwjre        : 'windows-i586.zip',
+        lwjreOSX     : 'macos-amd64.zip'
+]
+
+task downloadJreAll {
+    group 'Download'
+    description 'Downloads JRE for all platforms'
+}
+
+jreUrlFilenames.each { os, file ->
+    def packedJre = new File("$rootDir/jre/$jreVersion/$file")
+    def unpackedJre = new File("$distsDir/app/$os")
+
+    def downloadTask = task("downloadJre$os") {
+        group 'Download'
+        description "Downloads JRE for $os"
+
+        doFirst {
+            download {
+                src "$jreUrlBase-$file"
+                dest packedJre
+                overwrite false
+            }
+        }
+
+        doLast {
+            // Unpack the JRE
+            if (!unpackedJre.exists()) {
+                unpackedJre.mkdirs()
+                copy {
+                    from(file.endsWith("zip")
+                            ? zipTree(packedJre)
+                            : tarTree(packedJre)) {
+                        eachFile { fcd ->
+                            fcd.relativePath = new RelativePath(
+                                    true, fcd.relativePath.segments.drop(1))
+                        }
+                        includeEmptyDirs = false
+                    }
+                    into unpackedJre
+                }
+            }
+        }
+    }
+
+    downloadJreAll.dependsOn downloadTask
+}
+
+

desktop/build.gradle

@@ -1,4 +1,25 @@
+/*
+ * Copyright 2020 The Terasology Foundation
+ *
+ * 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.
+ */
+
+plugins {
+    id 'de.undercouch.download' version '4.0.4'
+}
+
 apply from: '../config/gradle/common.gradle'
+apply from: "../config/gradle/jre.gradle"
 
 project.ext.mainClassName = "org.destinationsol.desktop.SolDesktop"
 
@@ -104,14 +125,29 @@ task distUnbundledJRE() {
 distUnbundledJRE.finalizedBy libsDist
 distUnbundledJRE.finalizedBy moduleDist
 
-task distUnbundledJREZip(type: Zip) {
+task distZipUnbundledJRE(type: Zip) {
     description = "Creates an application package and zip archive without any bundled JRE."
 
     dependsOn distUnbundledJRE
     from "$distsDir/app"
     archiveName = "DestinationSol.zip"
 }
 
+task distBundleJREs {
+    description = "Creates an application package with a bundled JRE."
+
+    dependsOn distUnbundledJRE
+    dependsOn downloadJreAll
+}
+
+task distZipBundleJREs (type: Zip) {
+    description = "Creates an application package and zip archive with a bundled JRE."
+
+    dependsOn distBundleJREs
+    from "$distsDir/app"
+    archiveName = "DestinationSol.zip"
+}
+
 // TODO: LibGDX Generated config for Eclipse. Needs adjustment for assets not being in the Android facade
 eclipse {
     project {