use NIO when available for recursive file deletion

2026-09-27 10:03:11 +07:00 · 2015-02-13 18:03:54 +01:00
parent 3b80735407
commit 7d86632067
2 changed files with 122 additions and 2 deletions
@@ -24,6 +24,10 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.TestOnly;

 import java.io.*;
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
 import java.nio.channels.FileChannel;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
@@ -66,6 +70,81 @@ public class FileUtilRt {

  private static String ourCanonicalTempPathCache = null;

+  protected static final boolean NIO_FILE_API_AVAILABLE;
+
+  // todo: replace reflection with normal code after migration to JDK 1.8
+  private static Method ourFilesDeleteIfExistsMethod;
+  private static Method ourFilesWalkMethod;
+  private static Method ourFileToPathMethod;
+  private static Object ourDeletionVisitor;
+  static {
+    boolean initSuccess = false;
+    try {
+      final Class<?> pathClass = Class.forName("java.nio.file.Path");
+      final Class<?> visitorClass = Class.forName("java.nio.file.FileVisitor");
+      final Class<?> filesClass = Class.forName("java.nio.file.Files");
+
+      ourFileToPathMethod = Class.forName("java.io.File").getMethod("toPath");
+      ourFilesWalkMethod = filesClass.getMethod("walkFileTree", pathClass, visitorClass);
+      ourFilesDeleteIfExistsMethod = filesClass.getMethod("deleteIfExists", pathClass);
+      final Class<?> fileVisitResultClass = Class.forName("java.nio.file.FileVisitResult");
+      final Object Result_Continue = fileVisitResultClass.getDeclaredField("CONTINUE").get(null);
+      final Object Result_Terminate = fileVisitResultClass.getDeclaredField("TERMINATE").get(null);
+      ourDeletionVisitor = Proxy.newProxyInstance(FileUtilRt.class.getClassLoader(), new Class[]{visitorClass}, new InvocationHandler() {
+        @Override
+        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+          if (args.length == 2) {
+            final Object second = args[1];
+            if (second instanceof Throwable) {
+              throw (Throwable)second;
+            }
+            final String methodName = method.getName();
+            if ("visitFile".equals(methodName) || "postVisitDirectory".equals(methodName)) {
+              if (!performDelete(args[0])) {
+                return Result_Terminate;
+              }
+            }
+          }
+          return Result_Continue;
+        }
+
+        private boolean performDelete(@NotNull final Object fileObject) {
+          Boolean result = doIOOperation(new RepeatableIOOperation<Boolean, RuntimeException>() {
+            public Boolean execute(boolean lastAttempt) {
+              try {
+                //Files.deleteIfExists(file);
+                ourFilesDeleteIfExistsMethod.invoke(null, fileObject);
+                return Boolean.TRUE;
+              }
+              catch (InvocationTargetException e) {
+                if (!(e.getCause() instanceof IOException)) {
+                  return Boolean.FALSE;
+                }
+              }
+              catch (IllegalAccessException e) {
+                return Boolean.FALSE;
+              }
+              return lastAttempt? Boolean.FALSE : null;
+            }
+          });
+          return Boolean.TRUE.equals(result);
+        }
+
+      });
+      initSuccess = true;
+      LOG.info("Using NIO-based file deletion");
+    }
+    catch (Throwable ignored) {
+      LOG.info("Was not able to detect NIO API");
+      ourFileToPathMethod = null;
+      ourFilesWalkMethod = null;
+      ourFilesDeleteIfExistsMethod = null;
+      ourDeletionVisitor = null;
+    }
+    NIO_FILE_API_AVAILABLE = initSuccess;
+  }
+
+
  @NotNull
  public static String getExtension(@NotNull String fileName) {
    int index = fileName.lastIndexOf('.');
@@ -538,10 +617,44 @@ public class FileUtilRt {
   * @return true if the file did not exist or was successfully deleted 
   */
  public static boolean delete(@NotNull File file) {
+    if (NIO_FILE_API_AVAILABLE) {
+      return deleteRecursivelyNIO(file);
+    }
+    return deleteRecursively(file);
+  }
+
+  protected static boolean deleteRecursivelyNIO(File file) {
+    try {
+      /*
+      Files.walkFileTree(file.toPath(), new SimpleFileVisitor<Path>() {
+        @Override
+        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
+          Files.deleteIfExists(file);
+          return FileVisitResult.CONTINUE;
+        }
+      
+        @Override
+        public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
+          Files.deleteIfExists(dir);
+          return FileVisitResult.CONTINUE;
+        }
+      });
+      */
+      final Object pathObject = ourFileToPathMethod.invoke(file);
+      ourFilesWalkMethod.invoke(null, pathObject, ourDeletionVisitor);
+    }
+    catch (Exception e) {
+      LOG.info(e);
+      return false;
+    }
+    return true;
+  }
+  
+  private static boolean deleteRecursively(@NotNull File file) {
    File[] files = file.listFiles();
    if (files != null) {
      for (File child : files) {
-        if (!delete(child)) return false;
+        if (!deleteRecursively(child)) return false;
      }
    }

@@ -421,6 +421,13 @@ public class FileUtil extends FileUtilRt {
  }

  public static boolean delete(@NotNull File file) {
+    if (NIO_FILE_API_AVAILABLE) {
+      return deleteRecursivelyNIO(file);
+    }
+    return deleteRecursively(file);
+  }
+
+  private static boolean deleteRecursively(@NotNull File file) {
    FileAttributes attributes = FileSystemUtil.getAttributes(file);
    if (attributes == null) return true;

@@ -428,7 +435,7 @@ public class FileUtil extends FileUtilRt {
      File[] files = file.listFiles();
      if (files != null) {
        for (File child : files) {
-          if (!delete(child)) return false;
+          if (!deleteRecursively(child)) return false;
        }
      }
    }