wilx commented on code in PR #1102: URL: https://github.com/apache/maven-compiler-plugin/pull/1102#discussion_r3736825895
########## src/main/java/org/apache/maven/plugin/compiler/DependencyState.java: ########## @@ -0,0 +1,306 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 org.apache.maven.plugin.compiler; + +import java.io.File; +import java.io.IOException; +import java.nio.charset.StandardCharsets; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.Paths; +import java.nio.file.attribute.BasicFileAttributes; +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; +import java.time.Instant; +import java.time.temporal.ChronoUnit; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collection; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +import org.apache.maven.plugin.MojoExecutionException; +import org.apache.maven.plugin.logging.Log; +import org.apache.maven.shared.incremental.IncrementalBuildHelper; +import org.codehaus.plexus.util.FileUtils; + +/** + * Persists the class path and module path used by a compiler Mojo execution and detects dependencies modified during + * the current Maven build while collecting that state. + */ +final class DependencyState { + private static final String STATE_FILE = "dependencies.lst"; + private static final String STATE_SEPARATOR = "\t"; + private static final Set<String> DEFAULT_FILE_EXTENSIONS = + Collections.unmodifiableSet(new HashSet<>(Arrays.asList("class", "jar"))); + + private DependencyState() {} + + static boolean hasChanged( + IncrementalBuildHelper incrementalBuildHelper, + File outputDirectory, + List<String> classpathElements, + List<String> modulepathElements, + Configuration configuration) { + Path stateFile = null; + try { + stateFile = incrementalBuildHelper.getMojoStatusDirectory().toPath().resolve(STATE_FILE); + } catch (MojoExecutionException e) { + configuration.log.warn("Error reading mojo status directory."); + } + + List<String> oldState = Collections.emptyList(); + boolean hasPreviousState = stateFile != null && Files.isRegularFile(stateFile); + if (hasPreviousState) { + try { + oldState = Files.readAllLines(stateFile); + } catch (IOException e) { + configuration.log.warn("Error while reading old dependency status: " + stateFile); + hasPreviousState = false; + } + } + + List<String> newState = new ArrayList<>(); + ScanContext context = new ScanContext(outputDirectory, configuration); + Path changedDependency = addDependencies(newState, "classpath:", classpathElements, context, null); + changedDependency = addDependencies(newState, "modulepath:", modulepathElements, context, changedDependency); + + if (stateFile != null) { + try { + Files.write(stateFile, newState); + } catch (IOException e) { + configuration.log.warn("Error while writing new dependency status: " + stateFile); + } + } + + if (hasPreviousState && !oldState.equals(newState)) { + if (configuration.log.isDebugEnabled() || configuration.showChanges) { + logChanges(oldState, newState, configuration.log); + } + return true; + } + if (changedDependency != null) { + if (configuration.log.isDebugEnabled() || configuration.showChanges) { + configuration.log.info("\tNew dependency detected: " + changedDependency.toAbsolutePath()); + } + return true; + } + if (configuration.buildStartTime == null) { + configuration.log.debug("Cannot determine build start time, skipping incremental build detection."); + } + return false; + } + + private static Path addDependencies( + List<String> state, String prefix, List<String> pathElements, ScanContext context, Path changedDependency) { + for (String pathElement : pathElements) { + Path dependencyPath = Paths.get(pathElement).toAbsolutePath().normalize(); + if (!dependencyPath.equals(context.outputPath)) { + ModificationState modification = context.modifications.get(dependencyPath); + if (modification == null) { + modification = modificationState(dependencyPath, context); + context.modifications.put(dependencyPath, modification); + } + state.add(prefix + dependencyPath + STATE_SEPARATOR + modification.recordedState); + if (changedDependency == null && modification.changedDependency != null) { + changedDependency = modification.changedDependency; + } + } + } + return changedDependency; + } + + /** + * Returns {@code size:mtime} for a file, or {@code relevant-file-count:metadata-sha256} for a directory. + * The directory digest covers each relevant file's relative path, size and modification time. + */ + private static ModificationState modificationState(Path dependency, ScanContext context) { + if (!Files.isDirectory(dependency)) { + try { + BasicFileAttributes attributes = readAttributes(dependency); + Path changedDependency = context.fileExtensions.contains(FileUtils.extension( + dependency.getFileName().toString())) + && changedSinceBuildStart(attributes, context) + ? dependency + : null; + return new ModificationState(fileMetadata(attributes), changedDependency); + } catch (IOException e) { + context.log.warn("I/O error reading dependency state: " + dependency + ": " + e.getMessage()); + return new ModificationState("unreadable", null); + } + } + + List<Path> files; + try (Stream<Path> walk = Files.walk(dependency)) { + files = walk.filter(Files::isRegularFile) + .filter(file -> context.fileExtensions.contains( + FileUtils.extension(file.getFileName().toString()))) + .sorted() + .collect(Collectors.toList()); + } catch (IOException e) { + context.log.warn("I/O error reading dependency state: " + dependency + ": " + e.getMessage()); + return new ModificationState("unreadable", null); + } + + MessageDigest digest = newDigest(); + Path changedDependency = null; + boolean unreadable = false; + for (Path file : files) { + try { + BasicFileAttributes attributes = readAttributes(file); + update(digest, dependency.relativize(file).toString()); + update(digest, fileMetadata(attributes)); + if (changedDependency == null && changedSinceBuildStart(attributes, context)) { + changedDependency = file; + } + } catch (IOException e) { + if (!unreadable) { + context.log.warn("I/O error reading dependency state: " + dependency + ": " + e.getMessage()); + unreadable = true; + } + } + } + String recordedState = unreadable ? "unreadable" : files.size() + ":" + toHexString(digest.digest()); + return new ModificationState(recordedState, changedDependency); + } + + private static BasicFileAttributes readAttributes(Path file) throws IOException { + return Files.readAttributes(file, BasicFileAttributes.class); + } + + private static String fileMetadata(BasicFileAttributes attributes) { + return attributes.size() + ":" + attributes.lastModifiedTime().toMillis(); Review Comment: It fits into how it is stored and used. This way the checksum of files in a dir is only computed via checksum of their metadata checksums/strings, there is only one `update` function. Doing anything else would complicate things unnecessarily. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
