Add an easy way to include fabric api modules (#183)

* Add an easy way to include fabric api modules

* Quick update

* Fix crash when reading empty aw file, fix -SNAPSHOT versions plugin marker not being published

* rename methods

src/main/java/net/fabricmc/loom/AbstractPlugin.java

@@ -62,6 +62,7 @@ import net.fabricmc.loom.util.SetupIntelijRunConfigs;
 import net.fabricmc.loom.util.mixin.JavaApInvoker;
 import net.fabricmc.loom.util.mixin.KaptApInvoker;
 import net.fabricmc.loom.util.mixin.ScalaApInvoker;
+import net.fabricmc.loom.util.FabricApiExtension;
 
 public class AbstractPlugin implements Plugin<Project> {
 	protected Project project;
@@ -86,6 +87,7 @@ public class AbstractPlugin implements Plugin<Project> {
 		project.apply(ImmutableMap.of("plugin", "idea"));
 
 		project.getExtensions().create("minecraft", LoomGradleExtension.class, project);
+		project.getExtensions().create("fabricApi", FabricApiExtension.class, project);
 
 		// Force add Mojang repository
 		addMavenRepo(target, "Mojang", "https://libraries.minecraft.net/");

src/main/java/net/fabricmc/loom/util/FabricApiExtension.java

@@ -0,0 +1,120 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2016, 2017, 2018 FabricMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.fabricmc.loom.util;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+
+import org.gradle.api.Project;
+import org.gradle.api.artifacts.Dependency;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.NodeList;
+
+import net.fabricmc.loom.LoomGradleExtension;
+
+public class FabricApiExtension {
+	private Project project;
+
+	public FabricApiExtension(Project project) {
+		this.project = project;
+	}
+
+	private static HashMap<String, Map<String, String>> moduleVersionCache = new HashMap<>();
+
+	public Dependency module(String moduleName, String fabricApiVersion) {
+		return project.getDependencies()
+				.create(getDependencyNotation(moduleName, fabricApiVersion));
+	}
+
+	public String moduleVersion(String moduleName, String fabricApiVersion) {
+		String moduleVersion = moduleVersionCache
+				.computeIfAbsent(fabricApiVersion, this::populateModuleVersionMap)
+				.get(moduleName);
+
+		if (moduleVersion == null) {
+			throw new RuntimeException("Failed to find module version for module: " + moduleName);
+		}
+
+		return moduleVersion;
+	}
+
+	private String getDependencyNotation(String moduleName, String fabricApiVersion) {
+		return String.format("net.fabricmc.fabric-api:%s:%s", moduleName, moduleVersion(moduleName, fabricApiVersion));
+	}
+
+	private Map<String, String> populateModuleVersionMap(String fabricApiVersion) {
+		File pomFile = getApiMavenPom(fabricApiVersion);
+
+		try {
+			DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
+			DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
+			Document pom = docBuilder.parse(pomFile);
+
+			Map<String, String> versionMap = new HashMap<>();
+
+			NodeList dependencies = ((Element) pom.getElementsByTagName("dependencies").item(0)).getElementsByTagName("dependency");
+
+			for (int i = 0; i < dependencies.getLength(); i++) {
+				Element dep = (Element) dependencies.item(i);
+				Element artifact = (Element) dep.getElementsByTagName("artifactId").item(0);
+				Element version = (Element) dep.getElementsByTagName("version").item(0);
+
+				if (artifact == null || version == null) {
+					throw new RuntimeException("Failed to find artifact or version");
+				}
+
+				project.getLogger().lifecycle(artifact.getTextContent() + " : " + version.getTextContent());
+
+				versionMap.put(artifact.getTextContent(), version.getTextContent());
+			}
+
+			return versionMap;
+		} catch (Exception e) {
+			throw new RuntimeException("Failed to parse " + pomFile.getName(), e);
+		}
+	}
+
+	private File getApiMavenPom(String fabricApiVersion) {
+		LoomGradleExtension extension = project.getExtensions().getByType(LoomGradleExtension.class);
+
+		File mavenPom = new File(extension.getUserCache(), "fabric-api/" + fabricApiVersion + ".pom");
+
+		try {
+			URL url = new URL(String.format("https://maven.fabricmc.net/net/fabricmc/fabric-api/fabric-api/%1$s/fabric-api-%1$s.pom", fabricApiVersion));
+			DownloadUtil.downloadIfChanged(url, mavenPom, project.getLogger());
+		} catch (IOException e) {
+			throw new RuntimeException("Failed to download maven info for " + fabricApiVersion);
+		}
+
+		return mavenPom;
+	}
+}