Leverage Maven local repository for p2 cache directory in Eclipse step

Author: kevinleturc

lib-extra/src/main/java/com/diffplug/spotless/extra/EquoBasedStepBuilder.java

@@ -37,6 +37,7 @@
 import com.diffplug.spotless.SerializedFunction;
 
 import dev.equo.solstice.NestedJars;
+import dev.equo.solstice.p2.CacheLocations;
 import dev.equo.solstice.p2.P2ClientCache;
 import dev.equo.solstice.p2.P2Model;
 import dev.equo.solstice.p2.P2QueryCache;
@@ -52,6 +53,7 @@ public abstract class EquoBasedStepBuilder {
 	private String formatterVersion;
 	private Iterable<File> settingsFiles = new ArrayList<>();
 	private Map<String, String> p2Mirrors = Map.of();
+	private File cacheDirectory;
 
 	/** Initialize valid default configuration, taking latest version */
 	public EquoBasedStepBuilder(String formatterName, Provisioner mavenProvisioner, @Nullable String defaultVersion, SerializedFunction<State, FormatterFunc> stateToFormatter) {
@@ -77,6 +79,10 @@ public void setP2Mirrors(Collection<P2Mirror> p2Mirrors) {
 		this.p2Mirrors = p2Mirrors.stream().collect(toMap(P2Mirror::getPrefix, P2Mirror::getUrl));
 	}
 
+	public void setCacheDirectory(File cacheDirectory) {
+		this.cacheDirectory = cacheDirectory;
+	}
+
 	protected abstract P2Model model(String version);
 
 	protected void addPlatformRepo(P2Model model, String version) {
@@ -101,6 +107,9 @@ public FormatterStep build() {
 		var roundtrippableState = new EquoStep(formatterVersion, FileSignature.promise(settingsFiles), JarState.promise(() -> {
 			P2QueryResult query;
 			try {
+				if (null != cacheDirectory) {
+					CacheLocations.override_p2data = cacheDirectory.toPath().resolve("dev/equo/p2-data").toFile();
+				}
 				query = createModelWithMirrors().query(P2ClientCache.PREFER_OFFLINE, P2QueryCache.ALLOW);
 			} catch (Exception x) {
 				throw new IOException("Failed to load " + formatterName + ": " + x, x);

plugin-maven/src/main/java/com/diffplug/spotless/maven/AbstractSpotlessMojo.java

@@ -379,6 +379,7 @@ private FileLocator getFileLocator() {
 	private List<FormatterFactory> getFormatterFactories() {
 		return Stream.concat(formats.stream(), Stream.of(groovy, java, scala, kotlin, cpp, typescript, javascript, antlr4, pom, sql, python, markdown, json, shell, yaml, gherkin, go))
 				.filter(Objects::nonNull)
+				.map(factory -> factory.init(repositorySystemSession))
 				.collect(toList());
 	}
 

plugin-maven/src/main/java/com/diffplug/spotless/maven/FormatterFactory.java

@@ -30,6 +30,7 @@
 
 import org.apache.maven.plugins.annotations.Parameter;
 import org.apache.maven.project.MavenProject;
+import org.eclipse.aether.RepositorySystemSession;
 
 import com.diffplug.common.collect.Sets;
 import com.diffplug.spotless.FormatExceptionPolicyStrict;
@@ -197,4 +198,9 @@ private static boolean formatterStepOverriden(FormatterStepFactory global, List<
 		return allConfigured.stream()
 				.anyMatch(configured -> configured.getClass() == global.getClass());
 	}
+
+	public FormatterFactory init(RepositorySystemSession repositorySystemSession) {
+		stepFactories.forEach(factory -> factory.init(repositorySystemSession));
+		return this;
+	}
 }

plugin-maven/src/main/java/com/diffplug/spotless/maven/FormatterStepFactory.java

@@ -15,9 +15,15 @@
  */
 package com.diffplug.spotless.maven;
 
+import org.eclipse.aether.RepositorySystemSession;
+
 import com.diffplug.spotless.FormatterStep;
 
 public interface FormatterStepFactory {
 
 	FormatterStep newFormatterStep(FormatterStepConfig config);
+
+	default void init(RepositorySystemSession repositorySystemSession) {
+		// nothing
+	}
 }

plugin-maven/src/main/java/com/diffplug/spotless/maven/java/Eclipse.java

@@ -21,6 +21,7 @@
 import java.util.List;
 
 import org.apache.maven.plugins.annotations.Parameter;
+import org.eclipse.aether.RepositorySystemSession;
 
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.extra.EquoBasedStepBuilder;
@@ -40,6 +41,8 @@ public class Eclipse implements FormatterStepFactory {
 	@Parameter
 	private List<P2Mirror> p2Mirrors = new ArrayList<>();
 
+	private File cacheDirectory;
+
 	@Override
 	public FormatterStep newFormatterStep(FormatterStepConfig stepConfig) {
 		EquoBasedStepBuilder eclipseConfig = EclipseJdtFormatterStep.createBuilder(stepConfig.getProvisioner());
@@ -49,6 +52,13 @@ public FormatterStep newFormatterStep(FormatterStepConfig stepConfig) {
 			eclipseConfig.setPreferences(Arrays.asList(settingsFile));
 		}
 		eclipseConfig.setP2Mirrors(p2Mirrors);
+		if (null != cacheDirectory) {
+			eclipseConfig.setCacheDirectory(cacheDirectory);
+		}
 		return eclipseConfig.build();
 	}
+
+	public void init(RepositorySystemSession repositorySystemSession) {
+		this.cacheDirectory = repositorySystemSession.getLocalRepository().getBasedir();
+	}
 }