Acquire read action for VFS visitor

platform/core-api/src/com/intellij/openapi/vfs/VfsUtilCore.java

@@ -15,6 +15,8 @@
  */
 package com.intellij.openapi.vfs;
 
+import com.intellij.openapi.application.AccessToken;
+import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.roots.ContentIterator;
 import com.intellij.openapi.util.io.BufferExposingByteArrayInputStream;
 import com.intellij.openapi.util.io.FileUtil;
@@ -26,6 +28,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.*;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
@@ -184,9 +187,8 @@ public class VfsUtilCore {
     return result.skipToParent != root;
   }
 
+  @SuppressWarnings("UnsafeVfsRecursion")
   public static VirtualFileVisitor.Result visitChildrenRecursively(@NotNull VirtualFile file, @NotNull VirtualFileVisitor visitor) {
-    if (!file.isValid()) return VirtualFileVisitor.CONTINUE;
-
     visitor.pushFrame();
     try {
       final boolean visited = visitor.allowVisitFile(file);
@@ -195,22 +197,26 @@ public class VfsUtilCore {
         if (result.skipChildren) return result;
       }
 
-      if (!visitor.allowVisitChildren(file)) return VirtualFileVisitor.CONTINUE;
+      Iterable<VirtualFile> childrenIterable = null;
 
-      if (!visitor.depthLimitReached()) {
-        final Iterable<VirtualFile> iterable = visitor.getChildrenIterable(file);
-        if (iterable != null) {
-          for (VirtualFile child : iterable) {
-            VirtualFileVisitor.Result result = visitChildrenRecursively(child, visitor);
-            if (result.skipToParent != null && result.skipToParent != child) return result;
+      final AccessToken token = ApplicationManager.getApplication().acquireReadActionLock();
+      try {
+        if (!file.isValid() || !visitor.allowVisitChildren(file)) return VirtualFileVisitor.CONTINUE;
+        if (!visitor.depthLimitReached()) {
+          childrenIterable = visitor.getChildrenIterable(file);
+          if (childrenIterable == null) {
+            childrenIterable = Arrays.asList(file.getChildren());
           }
         }
-        else {
-          @SuppressWarnings("UnsafeVfsRecursion") VirtualFile[] children = file.getChildren();
-          for (VirtualFile child : children) {
-            VirtualFileVisitor.Result result = visitChildrenRecursively(child, visitor);
-            if (result.skipToParent != null && result.skipToParent != child) return result;
-          }
+      }
+      finally {
+        token.finish();
+      }
+
+      if (childrenIterable != null) {
+        for (VirtualFile child : childrenIterable) {
+          VirtualFileVisitor.Result result = visitChildrenRecursively(child, visitor);
+          if (result.skipToParent != null && result.skipToParent != child) return result;
         }
       }
 

platform/platform-tests/testSrc/com/intellij/openapi/vfs/VirtualFileVisitorTest.java

@@ -19,6 +19,7 @@ import com.intellij.mock.MockVirtualFile;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.Ref;
 import com.intellij.openapi.util.text.StringUtil;
+import com.intellij.testFramework.PlatformUltraLiteTestFixture;
 import com.intellij.util.Function;
 import com.intellij.util.NullableFunction;
 import org.jetbrains.annotations.NotNull;
@@ -32,10 +33,13 @@ import java.util.Collections;
 import static org.junit.Assert.assertEquals;
 
 public class VirtualFileVisitorTest {
+  private static PlatformUltraLiteTestFixture myFixture;
   private static VirtualFile myRoot;
 
   @BeforeClass
   public static void setUp() throws Exception {
+    myFixture = PlatformUltraLiteTestFixture.getFixture();
+    myFixture.setUp();
     myRoot =
       dir("/",
           dir("d1",
@@ -54,6 +58,7 @@ public class VirtualFileVisitorTest {
   @AfterClass
   public static void tearDown() throws Exception {
     myRoot = null;
+    myFixture.tearDown();
   }
 
   @Test

platform/testFramework/src/com/intellij/testFramework/PlatformUltraLiteTestFixture.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2000-2012 JetBrains s.r.o.
+ *
+ * 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.intellij.testFramework;
+
+import com.intellij.mock.MockApplication;
+import com.intellij.openapi.Disposable;
+import com.intellij.openapi.application.Application;
+import com.intellij.openapi.application.ApplicationManager;
+import com.intellij.openapi.util.Disposer;
+import org.jetbrains.annotations.NotNull;
+
+public class PlatformUltraLiteTestFixture {
+  @NotNull
+  public static PlatformUltraLiteTestFixture getFixture() {
+    return new PlatformUltraLiteTestFixture();
+  }
+
+  private Disposable myAppDisposable = null;
+
+  private PlatformUltraLiteTestFixture() { }
+
+  public void setUp() {
+    final Application application = ApplicationManager.getApplication();
+    if (application == null) {
+      myAppDisposable = Disposer.newDisposable();
+      ApplicationManager.setApplication(new MockApplication(myAppDisposable), myAppDisposable);
+    }
+  }
+
+  public void tearDown() {
+    if (myAppDisposable != null) {
+      Disposer.dispose(myAppDisposable);
+    }
+  }
+}