Replace usage of jruby DirectoryWalker with Java NIO API (#532)

CHANGELOG.adoc

@@ -37,6 +37,7 @@ Maintenance::
   * Rewrite `AsciidoctorHttpMojoTest` to Java to make it more approachable (#516)
   * Rewrite `AsciidoctorZipMojoTest` to Java to make it more approachable (#518)
   * Rewrite `AsciidoctorDoxiaParserTest` to Java + remove Groovy & Spock configurations (#519)
+  * Replace usage of internal Asciidoctorj `DirectoryWalker` with Java NIO API (https://github.com/stdll[@stdll]) (#532)
 
 == v2.1.0 (2020-09-15)
 

src/main/java/org/asciidoctor/maven/AsciidoctorMojo.java

@@ -12,9 +12,7 @@
 import org.apache.maven.shared.filtering.MavenResourcesExecution;
 import org.apache.maven.shared.filtering.MavenResourcesFiltering;
 import org.asciidoctor.*;
-import org.asciidoctor.jruby.AsciiDocDirectoryWalker;
 import org.asciidoctor.jruby.AsciidoctorJRuby;
-import org.asciidoctor.jruby.DirectoryWalker;
 import org.asciidoctor.jruby.internal.JRubyRuntimeContext;
 import org.asciidoctor.maven.extensions.AsciidoctorJExtensionRegistry;
 import org.asciidoctor.maven.extensions.ExtensionConfiguration;
@@ -25,14 +23,15 @@
 import org.asciidoctor.maven.log.LogRecordsProcessors;
 import org.asciidoctor.maven.log.MemoryLogHandler;
 import org.asciidoctor.maven.process.AsciidoctorHelper;
-import org.asciidoctor.maven.process.CustomExtensionDirectoryWalker;
 import org.asciidoctor.maven.process.ResourcesProcessor;
 import org.asciidoctor.maven.process.SourceDirectoryFinder;
+import org.asciidoctor.maven.process.SourceDocumentFinder;
 import org.jruby.Ruby;
 
 import javax.inject.Inject;
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.*;
 import java.util.logging.Logger;
 
@@ -440,13 +439,12 @@ protected List<File> calculateSourceFiles(File sourceDirectory) {
         if (sourceDocumentName != null)
             return Arrays.asList(new File(sourceDirectory, sourceDocumentName));
 
-        // Both DirectoryWalkers filter out internal sources and path (_ prefix)
-        final String sourceDirectoryAbsolutePath = sourceDirectory.getAbsolutePath();
-        final DirectoryWalker directoryWalker = sourceDocumentExtensions.isEmpty()
-                ? new AsciiDocDirectoryWalker(sourceDirectoryAbsolutePath)
-                : new CustomExtensionDirectoryWalker(sourceDirectoryAbsolutePath, sourceDocumentExtensions);
+        Path sourceDirectoryPath = sourceDirectory.toPath();
+        SourceDocumentFinder finder = new SourceDocumentFinder();
 
-        return directoryWalker.scan();
+        return sourceDocumentExtensions.isEmpty() ?
+            finder.find(sourceDirectoryPath) :
+            finder.find(sourceDirectoryPath, sourceDocumentExtensions);
     }
 
     protected void convertFile(Asciidoctor asciidoctor, Map<String, Object> options, File f) {

src/main/java/org/asciidoctor/maven/process/SourceDocumentFinder.java

@@ -0,0 +1,74 @@
+package org.asciidoctor.maven.process;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Collections;
+import java.util.List;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * Finds all source documents inside a source directory.
+ * It traverses the source directory and all subdirectories. It can match custom file extensions.
+ * If none are specified, it matches <code>.asc</code>, <code>.asciidoc</code>, <code>.ad</code> and <code>.adoc</code>.
+ * Files and directories starting with an underscore (<code>_</code>) are ignored.
+ *
+ * @author stdll
+ */
+public class SourceDocumentFinder {
+
+    /** Pattern for matching standard file extensions. */
+    private static final String STANDARD_FILE_EXTENSIONS_PATTERN = "^[^_.].*\\.a((sc(iidoc)?)|d(oc)?)$";
+
+    /** Prefix for matching custom file extensions. */
+    private static final String CUSTOM_FILE_EXTENSIONS_PATTERN_PREFIX = "^[^_.].*\\.(";
+
+    /** Suffix for matching custom file extensions. */
+    private static final String CUSTOM_FILE_EXTENSIONS_PATTERN_SUFFIX = ")$";
+
+    /**
+     * Finds all source documents inside the source directory with standard file extensions.
+     *
+     * @param sourceDirectory source directory
+     * @return the list of all matching source documents.
+     */
+    public List<File> find(Path sourceDirectory) {
+        return find(sourceDirectory, Pattern.compile(STANDARD_FILE_EXTENSIONS_PATTERN));
+    }
+
+    /**
+     * Finds all source documents inside the source directory with custom file extensions.
+     *
+     * @param sourceDirectory          source directory
+     * @param sourceDocumentExtensions custom file extensions
+     * @return the list of all matching source documents.
+     */
+    public List<File> find(Path sourceDirectory, List<String> sourceDocumentExtensions) {
+        String extensionPattern = sourceDocumentExtensions.stream().collect(Collectors
+            .joining("|", CUSTOM_FILE_EXTENSIONS_PATTERN_PREFIX, CUSTOM_FILE_EXTENSIONS_PATTERN_SUFFIX));
+        return find(sourceDirectory, Pattern.compile(extensionPattern));
+    }
+
+    private List<File> find(Path sourceDirectory, Pattern sourceDocumentPattern) {
+        try (Stream<Path> sourceDocumentCandidates = Files.walk(sourceDirectory)) {
+            return sourceDocumentCandidates.filter(Files::isRegularFile)
+                // Filter all documents that don't match the file extension pattern.
+                .filter(p -> sourceDocumentPattern.matcher(p.getFileName().toString()).matches())
+                // Filter all documents that are part of ignored directories.
+                .filter(p -> {
+                    for (Path part : p) {
+                        if (part.toString().startsWith("_")) {
+                            return false;
+                        }
+                    }
+                    return true;
+                }).map(Path::toFile).collect(Collectors.toList());
+        } catch (IOException e) {
+            // Can't access the source directory.
+            return Collections.emptyList();
+        }
+    }
+}

src/test/java/org/asciidoctor/maven/process/SourceDocumentFinderTest.java

@@ -0,0 +1,139 @@
+package org.asciidoctor.maven.process;
+
+import java.io.File;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class SourceDocumentFinderTest {
+
+    private static final String DEFAULT_SOURCE_DIRECTORY = "src/test/resources/src/asciidoctor";
+
+    @Test
+    public void should_init_SourceDocumentFinder() {
+        // when
+        SourceDocumentFinder walker = new SourceDocumentFinder();
+        // then
+        assertThat(walker).isNotNull();
+    }
+
+    @Test
+    public void should_match_standard_file_extensions() {
+        // given
+        final String rootDirectory = DEFAULT_SOURCE_DIRECTORY + "/file-extensions";
+
+        // when
+        List<File> files = new SourceDocumentFinder().find(Paths.get(rootDirectory));
+
+        // then
+        assertThat(files)
+            .isNotEmpty()
+            .map(File::getName)
+            .allMatch(name -> name.endsWith("ad") || name.endsWith("adoc") || name.endsWith("asc") ||
+                name.endsWith("asciidoc"));
+    }
+
+    @Test
+    public void should_match_custom_file_extension() {
+        // given
+        final String rootDirectory = DEFAULT_SOURCE_DIRECTORY + "/file-extensions";
+
+        // when
+        List<File> files = new SourceDocumentFinder().find(Paths.get(rootDirectory), Collections.singletonList("my-adoc"));
+
+        // then
+        assertThat(files)
+            .isNotEmpty()
+            .allMatch(file -> file.getName().endsWith("my-adoc"));
+    }
+
+    @Test
+    public void should_match_custom_file_extensions() {
+        // given
+        final String rootDirectory = DEFAULT_SOURCE_DIRECTORY + "/file-extensions";
+        List<String> customFileExtensions = new ArrayList<>();
+        customFileExtensions.add("my-adoc");
+        customFileExtensions.add("adoc");
+
+        // when
+        List<File> files = new SourceDocumentFinder().find(Paths.get(rootDirectory), customFileExtensions);
+
+        // then
+        assertThat(files)
+            .isNotEmpty()
+            .map(File::getName)
+            .allMatch(name -> name.endsWith("my-adoc") || name.endsWith("adoc"));
+    }
+
+    @Test
+    public void should_not_match_custom_empty_file_extensions() {
+        // given
+        final String rootDirectory = DEFAULT_SOURCE_DIRECTORY + "/file-extensions";
+
+        // when
+        List<File> files = new SourceDocumentFinder().find(Paths.get(rootDirectory), Collections.emptyList());
+
+        // then
+        assertThat(files)
+            .isEmpty();
+    }
+
+    @Test
+    public void should_return_empty_list_if_wrong_source_directory() {
+        // given
+        final String rootDirectory = DEFAULT_SOURCE_DIRECTORY + "/file-extensions/non-existing";
+
+        // when
+        List<File> files = new SourceDocumentFinder().find(Paths.get(rootDirectory));
+
+        // then
+        assertThat(files)
+            .isEmpty();
+    }
+
+    @Test
+    public void should_exclude_internal_sources() {
+        // given
+        final String rootDirectory = DEFAULT_SOURCE_DIRECTORY + "/relative-path-treatment";
+        final List<String> fileExtensions = Collections.singletonList("adoc");
+
+        // when
+        List<File> files = new SourceDocumentFinder().find(Paths.get(rootDirectory), fileExtensions);
+
+        // then
+        assertThat(files)
+                .isNotEmpty()
+                .allMatch(file -> !file.getName().startsWith("_"));
+    }
+
+    @Test
+    public void should_exclude_internal_directories() {
+        // given
+        final String rootDirectory = DEFAULT_SOURCE_DIRECTORY + "/relative-path-treatment";
+        final List<String> fileExtensions = Collections.singletonList("adoc");
+
+        // when
+        List<File> files = new SourceDocumentFinder().find(Paths.get(rootDirectory), fileExtensions);
+
+        // then
+        assertThat(files)
+                .isNotEmpty()
+                .allMatch(file -> !isContainedInInternalDirectory(file));
+    }
+
+    private boolean isContainedInInternalDirectory(File file) {
+        final String path = file.getPath();
+        int cursor = 0;
+        do {
+            cursor = path.indexOf(File.separator, cursor + 1);
+            if (path.charAt(cursor + 1) == '_')
+                return true;
+        } while (cursor != -1);
+        return false;
+    }
+}

src/test/resources/src/asciidoctor/file-extensions/sample

@@ -0,0 +1,28 @@
+Document Title
+==============
+Doc Writer <thedoc@asciidoctor.org>
+:idprefix: id_
+
+Preamble paragraph.
+
+NOTE: This is test, only a test.
+
+== Section A
+
+*Section A* paragraph.
+
+=== Section A Subsection
+
+*Section A* 'subsection' paragraph.
+
+== Section B
+
+*Section B* paragraph.
+
+.Section B list
+* Item 1
+* Item 2
+* Item 3
+
+[source,ruby]
+require 'asciidoctor'