platform/lang-impl/src/com/intellij/psi/util/proximity/SameLogicalRootWeigher.java

/*
 * Copyright 2000-2009 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.psi.util.proximity;

import com.intellij.openapi.util.NullableLazyKey;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.util.ProximityLocation;
import com.intellij.util.LogicalRoot;
import com.intellij.util.LogicalRootsManager;
import com.intellij.util.NullableFunction;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * @author peter
*/
public class SameLogicalRootWeigher extends ProximityWeigher {
  private static final NullableLazyKey<LogicalRoot, ProximityLocation> LOGICAL_ROOT_KEY = NullableLazyKey.create("logicalRoot", new NullableFunction<ProximityLocation, LogicalRoot>() {
    @Override
    public LogicalRoot fun(ProximityLocation proximityLocation) {
      return findLogicalRoot(proximityLocation.getPosition());
    }
  });

  @Override
  public Comparable weigh(@NotNull final PsiElement element, @NotNull final ProximityLocation location) {
    if (location.getPosition() == null){
      return null;
    }
    final LogicalRoot contextRoot = LOGICAL_ROOT_KEY.getValue(location);
    if (contextRoot == null) {
      return false;
    }

    return contextRoot.equals(findLogicalRoot(element));
  }

  @Nullable
  private static LogicalRoot findLogicalRoot(PsiElement element) {
    if (element == null) return null;

    final PsiFile psiFile = element.getContainingFile();
    if (psiFile == null) return null;

    final VirtualFile file = psiFile.getVirtualFile();
    if (file == null) return null;

    return LogicalRootsManager.getLogicalRootsManager(element.getProject()).findLogicalRoot(file);
  }
}