feat: Prepare Maven's IDE hook

Author: Dimitrii Lipiridi

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java

@@ -124,7 +124,7 @@ public void setEncoding(String name) {
 
 	/** @see #setRatchetFrom(String) */
 	public String getRatchetFrom() {
-		return ratchetFrom == RATCHETFROM_NOT_SET_AT_FORMAT_LEVEL ? spotless.getRatchetFrom() : ratchetFrom;
+		return ratchetFrom.equals(RATCHETFROM_NOT_SET_AT_FORMAT_LEVEL) ? spotless.getRatchetFrom() : ratchetFrom;
 	}
 
 	/**

plugin-maven/build.gradle

@@ -39,6 +39,7 @@ dependencies {
 	compileOnly "org.eclipse.aether:aether-api:${VER_ECLIPSE_AETHER}"
 
 	implementation "com.diffplug.durian:durian-core:${VER_DURIAN}"
+	implementation "com.diffplug.durian:durian-io:${VER_DURIAN}"
 	implementation "com.diffplug.durian:durian-collect:${VER_DURIAN}"
 	implementation("org.codehaus.plexus:plexus-resources:${VER_PLEXUS_RESOURCES}")
 	implementation "org.eclipse.jgit:org.eclipse.jgit:${VER_JGIT}"

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

@@ -187,9 +187,6 @@ public abstract class AbstractSpotlessMojo extends AbstractMojo {
 	@Parameter(property = "spotlessFiles")
 	private String filePatterns;
 
-	@Parameter(property = "spotlessIdeHook")
-	private String spotlessIdeHook;
-
 	@Parameter(property = LicenseHeaderStep.spotlessSetLicenseHeaderYearsFromGitHistory)
 	private String setLicenseHeaderYearsFromGitHistory;
 
@@ -254,10 +251,6 @@ private boolean shouldSkip() {
 	}
 
 	private List<File> collectFiles(FormatterFactory formatterFactory, FormatterConfig config) {
-		if (!(spotlessIdeHook == null || spotlessIdeHook.isEmpty())) {
-			return fetchFileFromIdeHook();
-		}
-
 		Optional<String> ratchetFrom = formatterFactory.ratchetFrom(config);
 		try {
 			final List<File> files;
@@ -271,30 +264,21 @@ private List<File> collectFiles(FormatterFactory formatterFactory, FormatterConf
 			}
 			final String[] includePatterns = this.filePatterns.split(",");
 			final List<Pattern> compiledIncludePatterns = Arrays.stream(includePatterns)
-					.map(Pattern::compile)
-					.collect(Collectors.toList());
+				.map(Pattern::compile)
+				.collect(Collectors.toList());
 			final Predicate<File> shouldInclude = file -> compiledIncludePatterns
-					.stream()
-					.anyMatch(filePattern -> filePattern.matcher(file.getAbsolutePath())
-							.matches());
+				.stream()
+				.anyMatch(filePattern -> filePattern.matcher(file.getAbsolutePath())
+					.matches());
 			return files
-					.stream()
-					.filter(shouldInclude)
-					.collect(toList());
+				.stream()
+				.filter(shouldInclude)
+				.collect(toList());
 		} catch (IOException e) {
 			throw new PluginException("Unable to scan file tree rooted at " + baseDir, e);
 		}
 	}
 
-	private List<File> fetchFileFromIdeHook() {
-		File file = new File(spotlessIdeHook);
-		if (!file.isAbsolute()) {
-			throw new PluginException("Argument passed to spotlessIdeHook must be an absolute path");
-		}
-
-		return List.of(file);
-	}
-
 	private List<File> collectFilesFromGit(FormatterFactory formatterFactory, String ratchetFrom) {
 		MatchPatterns includePatterns = MatchPatterns.from(
 				withNormalizedFileSeparators(getIncludes(formatterFactory)));
@@ -400,4 +384,8 @@ private UpToDateChecker createUpToDateChecker(Iterable<Formatter> formatters) {
 		}
 		return UpToDateChecker.wrapWithBuildContext(checker, buildContext);
 	}
+
+	protected File getBaseDir() {
+		return baseDir;
+	}
 }

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

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2016-2021 DiffPlug
+ *
+ * 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 com.diffplug.spotless.maven;
+
+import com.diffplug.common.base.Errors;
+import com.diffplug.common.io.ByteStreams;
+import com.diffplug.spotless.Formatter;
+import com.diffplug.spotless.PaddedCell;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.List;
+
+class IdeHook {
+
+	private static void dumpIsClean() {
+		System.err.println("IS CLEAN");
+	}
+
+	static void performHook(Iterable<File> projectFiles, String path, Formatter formatter, File projectDir, String ratchetFrom, boolean spotlessIdeHookUseStdIn, boolean spotlessIdeHookUseStdOut) {
+		File file = new File(path);
+		if (!file.isAbsolute()) {
+			System.err.println("Argument passed to spotlessIdeHook must be an absolute path");
+			return;
+		}
+		if (projectContainsFile(projectFiles, file)) {
+			try {
+				if (ratchetFrom != null) {
+					GitRatchetMaven ratchet = GitRatchetMaven.instance();
+					if (ratchet.isClean(projectDir, ratchet.rootTreeShaOf(projectDir, ratchetFrom), file)) {
+						dumpIsClean();
+						return;
+					}
+				}
+				byte[] bytes;
+				if (spotlessIdeHookUseStdIn) {
+					bytes = ByteStreams.toByteArray(System.in);
+				} else {
+					bytes = Files.readAllBytes(file.toPath());
+				}
+				PaddedCell.DirtyState dirty = PaddedCell.calculateDirtyState(formatter, file, bytes);
+				if (dirty.isClean()) {
+					dumpIsClean();
+				} else if (dirty.didNotConverge()) {
+					System.err.println("DID NOT CONVERGE");
+					System.err.println("Run 'spotlessDiagnose' for details https://github.com/diffplug/spotless/blob/main/PADDEDCELL.md");
+				} else {
+					System.err.println("IS DIRTY");
+					if (spotlessIdeHookUseStdOut) {
+						dirty.writeCanonicalTo(System.out);
+					} else {
+						dirty.writeCanonicalTo(file);
+					}
+				}
+			} catch (IOException e) {
+				e.printStackTrace(System.err);
+				throw Errors.asRuntime(e);
+			} finally {
+				System.err.close();
+				System.out.close();
+			}
+		}
+	}
+
+	private static boolean projectContainsFile(Iterable<File> projectFiles, File file) {
+		for (File projectFile : projectFiles) {
+			if (projectFile.equals(file)) {
+				return true;
+			}
+		}
+		return false;
+	}
+}

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

@@ -18,21 +18,39 @@
 import java.io.File;
 import java.io.IOException;
 
+import java.util.List;
+
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugins.annotations.Mojo;
 
 import com.diffplug.spotless.Formatter;
 import com.diffplug.spotless.PaddedCell;
 import com.diffplug.spotless.maven.incremental.UpToDateChecker;
 
+import org.apache.maven.plugins.annotations.Parameter;
+
 /**
  * Performs formatting of all source files according to configured formatters.
  */
 @Mojo(name = AbstractSpotlessMojo.GOAL_APPLY, threadSafe = true)
 public class SpotlessApplyMojo extends AbstractSpotlessMojo {
 
+	@Parameter(property = "spotlessIdeHook")
+	private String spotlessIdeHook;
+
+	@Parameter(property = "spotlessIdeHookUseStdIn")
+	private boolean spotlessIdeHookUseStdIn;
+
+	@Parameter(property = "spotlessIdeHookUseStdOut")
+	private boolean spotlessIdeHookUseStdOut;
+
 	@Override
 	protected void process(Iterable<File> files, Formatter formatter, UpToDateChecker upToDateChecker) throws MojoExecutionException {
+		if(isIdeHook()) {
+			IdeHook.performHook(files, spotlessIdeHook, formatter, getBaseDir(), null, spotlessIdeHookUseStdIn, spotlessIdeHookUseStdOut);
+			return;
+		}
+
 		ImpactedFilesTracker counter = new ImpactedFilesTracker();
 
 		for (File file : files) {
@@ -69,4 +87,17 @@ protected void process(Iterable<File> files, Formatter formatter, UpToDateChecke
 			getLog().debug(String.format("Spotless.%s has no target files. Examine your `<includes>`: https://github.com/diffplug/spotless/tree/main/plugin-maven#quickstart", formatter.getName()));
 		}
 	}
+
+	private boolean isIdeHook() {
+		return !(spotlessIdeHook == null || spotlessIdeHook.isEmpty());
+	}
+
+	private List<File> fetchFileFromIdeHook() {
+		File file = new File(spotlessIdeHook);
+		if (!file.isAbsolute()) {
+			throw new PluginException("Argument passed to spotlessIdeHook must be an absolute path");
+		}
+
+		return List.of(file);
+	}
 }