python/src/com/jetbrains/python/psi/search/PyClassInheritorsSearchExecutor.java

/*
 * Copyright 2000-2013 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.jetbrains.python.psi.search;

import com.google.common.collect.ImmutableSet;
import com.intellij.openapi.application.AccessToken;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.project.Project;
import com.intellij.psi.search.ProjectScope;
import com.intellij.psi.stubs.StubIndex;
import com.intellij.util.Processor;
import com.intellij.util.QueryExecutor;
import com.intellij.util.containers.HashSet;
import com.jetbrains.python.psi.PyClass;
import com.jetbrains.python.psi.stubs.PySuperClassIndex;
import org.jetbrains.annotations.NotNull;

import java.util.Collection;
import java.util.Set;

/**
 * @author yole
 */
public class PyClassInheritorsSearchExecutor implements QueryExecutor<PyClass, PyClassInheritorsSearch.SearchParameters> {

  /**
   * These base classes are to general to look for inheritors list.
   */
  protected static final ImmutableSet<String> IGNORED_BASES = ImmutableSet.of("object", "BaseException", "Exception");

  public boolean execute(@NotNull final PyClassInheritorsSearch.SearchParameters queryParameters, @NotNull final Processor<PyClass> consumer) {
    Set<PyClass> processed = new HashSet<PyClass>();
    return processDirectInheritors(queryParameters.getSuperClass(), consumer, queryParameters.isCheckDeepInheritance(), processed);
  }

  private static boolean processDirectInheritors(
      final PyClass superClass, final Processor<PyClass> consumer, final boolean checkDeep, final Set<PyClass> processed
  ) {
    AccessToken accessToken = ApplicationManager.getApplication().acquireReadActionLock();
    try {
      final String superClassName = superClass.getName();
      if (superClassName == null || IGNORED_BASES.contains(superClassName)) return true;  // we don't want to look for inheritors of overly general classes
      if (processed.contains(superClass)) return true;
      processed.add(superClass);
      Project project = superClass.getProject();
      final Collection<PyClass> candidates = StubIndex.getElements(PySuperClassIndex.KEY, superClassName, project,
                                                                   ProjectScope.getAllScope(project), PyClass.class);
      for (PyClass candidate : candidates) {
        final PyClass[] classes = candidate.getSuperClasses();
        for (PyClass superClassCandidate : classes) {
          if (superClassCandidate.isEquivalentTo(superClass)) {
            if (!consumer.process(candidate)) {
              return false;
            }
            if (checkDeep && !processDirectInheritors(candidate, consumer, checkDeep, processed)) return false;
            break;
          }
        }
      }
    }
    finally {
      accessToken.finish();
    }
    return true;
  }
}