[IO-856] Try test on all OSs for GitHub CI (#699)

Author: garydgregory

src/main/java/org/apache/commons/io/FileUtils.java

@@ -23,6 +23,7 @@
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
+import java.io.FilenameFilter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -57,6 +58,7 @@
 import java.time.chrono.ChronoLocalDateTime;
 import java.time.chrono.ChronoZonedDateTime;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Date;
@@ -2311,6 +2313,22 @@ public static Collection<File> listFiles(final File directory, final IOFileFilte
         return toList(visitor.getFileList().stream().map(Path::toFile));
     }
 
+    @SuppressWarnings("null")
+    private static void listFiles(final File directory, final List<File> files, final boolean recursive, final FilenameFilter filter) {
+        // Only allocate if you must.
+        final List<File> dirs = recursive ? new ArrayList<>() : null;
+        Arrays.stream(directory.listFiles()).forEach(f -> {
+            if (recursive && f.isDirectory()) {
+                dirs.add(f);
+            } else if (f.isFile() && filter.accept(directory, f.getName())) {
+                files.add(f);
+            }
+        });
+        if (recursive) {
+            dirs.forEach(d -> listFiles(d, files, true, filter));
+        }
+    }
+
     /**
      * Lists files within a given directory (and optionally its subdirectories)
      * which match an array of extensions.
@@ -2322,9 +2340,11 @@ public static Collection<File> listFiles(final File directory, final IOFileFilte
      * @return a collection of {@link File} with the matching files
      */
     public static Collection<File> listFiles(final File directory, final String[] extensions, final boolean recursive) {
-        try (Stream<File> fileStream = Uncheck.get(() -> streamFiles(directory, recursive, extensions))) {
-            return toList(fileStream);
-        }
+        // IO-856: Don't use NIO to path walk, allocate as little as possible while traversing.
+        final List<File> files = new ArrayList<>();
+        final FilenameFilter filter = extensions != null ? new SuffixFileFilter(extensions) : TrueFileFilter.INSTANCE;
+        listFiles(directory, files, recursive, filter);
+        return files;
     }
 
     /**

src/test/java/org/apache/commons/io/FileUtilsListFilesTest.java

@@ -18,6 +18,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
@@ -44,8 +45,6 @@
 import org.apache.commons.lang3.function.Consumers;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.condition.EnabledOnOs;
-import org.junit.jupiter.api.condition.OS;
 import org.junit.jupiter.api.io.TempDir;
 
 /**
@@ -204,12 +203,12 @@ public void testListFilesByExtension() {
 
         files = FileUtils.listFiles(temporaryFolder, extensions, true);
         fileNames = filesToFilenames(files);
-        assertEquals(4, fileNames.size());
+        assertEquals(4, fileNames.size(), fileNames::toString);
         assertTrue(fileNames.contains("dummy-file.txt"));
         assertFalse(fileNames.contains("dummy-index.html"));
 
         files = FileUtils.listFiles(temporaryFolder, null, false);
-        assertEquals(2, files.size());
+        assertEquals(2, files.size(), files::toString);
         fileNames = filesToFilenames(files);
         assertTrue(fileNames.contains("dummy-build.xml"));
         assertTrue(fileNames.contains("README"));
@@ -238,7 +237,6 @@ public void testListFilesWithDeletion() throws IOException {
      * Tests <a href="https://issues.apache.org/jira/browse/IO-856">IO-856</a> ListFiles should not fail on vanishing files.
      */
     @Test
-    @EnabledOnOs(value = OS.WINDOWS)
     public void testListFilesWithDeletionThreaded() throws ExecutionException, InterruptedException {
         // test for IO-856
         // create random directory in tmp, create the directory if it does not exist
@@ -248,33 +246,42 @@ public void testListFilesWithDeletionThreaded() throws ExecutionException, Inter
             fail("Could not create file path: " + tempDir.getAbsolutePath());
         }
         final int waitTime = 10_000;
+        final int maxFiles = 500;
         final byte[] bytes = "TEST".getBytes(StandardCharsets.UTF_8);
         final CompletableFuture<Void> c1 = CompletableFuture.runAsync(() -> {
             final long endTime = System.currentTimeMillis() + waitTime;
-            while (System.currentTimeMillis() < endTime) {
+            int count = 0;
+            while (System.currentTimeMillis() < endTime && count < maxFiles) {
                 final File file = new File(tempDir.getAbsolutePath(), UUID.randomUUID() + ".deletetester");
                 file.deleteOnExit();
                 try {
                     Files.write(file.toPath(), bytes);
+                    count++;
                 } catch (final Exception e) {
                     fail("Could not create test file: '" + file.getAbsolutePath() + "': " + e, e);
                 }
                 if (!file.delete()) {
                     fail("Could not delete test file: '" + file.getAbsolutePath() + "'");
                 }
             }
+            // System.out.printf("Created %,d%n", count);
         });
         final CompletableFuture<Void> c2 = CompletableFuture.runAsync(() -> {
             final long endTime = System.currentTimeMillis() + waitTime;
+            int max = 0;
             try {
                 while (System.currentTimeMillis() < endTime) {
-                    FileUtils.listFiles(tempDir, new String[] { "\\.deletetester" }, false);
+                    final Collection<File> files = FileUtils.listFiles(tempDir, new String[] { "\\.deletetester" }, false);
+                    assertNotNull(files);
+                    max = Math.max(max, files.size());
                 }
             } catch (final Exception e) {
+                System.out.printf("List size max %,d%n", max);
                 fail("IO-856 test failure: " + e, e);
                 // The exception can be hidden.
                 e.printStackTrace();
             }
+            // System.out.printf("List size max %,d%n", max);
         });
         // wait for the threads to finish
         c1.get();