GistManagerImpl.java

/*
 * Copyright 2000-2017 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.util.gist;

import com.intellij.ide.util.PropertiesComponent;
import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.openapi.vfs.VirtualFileManager;
import com.intellij.openapi.vfs.newvfs.BulkFileListener;
import com.intellij.openapi.vfs.newvfs.events.VFileEvent;
import com.intellij.openapi.vfs.newvfs.events.VFilePropertyChangeEvent;
import com.intellij.psi.PsiFile;
import com.intellij.util.NullableFunction;
import com.intellij.util.containers.ContainerUtil;
import com.intellij.util.io.DataExternalizer;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.TestOnly;

import java.util.List;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author peter
 */
public class GistManagerImpl extends GistManager {
  private static final Set<String> ourKnownIds = ContainerUtil.newConcurrentSet();
  private static final String ourPropertyName = "file.gist.reindex.count";
  private final AtomicInteger myReindexCount = new AtomicInteger(PropertiesComponent.getInstance().getInt(ourPropertyName, 0));

  public GistManagerImpl() {
    ApplicationManager.getApplication().getMessageBus().connect().subscribe(VirtualFileManager.VFS_CHANGES, new BulkFileListener() {
      @Override
      public void after(@NotNull List<? extends VFileEvent> events) {
        if (events.stream().anyMatch(this::shouldDropCache)) {
          invalidateData();
        }
      }

      private boolean shouldDropCache(VFileEvent e) {
        if (!(e instanceof VFilePropertyChangeEvent)) return false;

        String propertyName = ((VFilePropertyChangeEvent)e).getPropertyName();
        return propertyName.equals(VirtualFile.PROP_NAME) || propertyName.equals(VirtualFile.PROP_ENCODING);
      }
    });
  }

  @NotNull
  @Override
  public <Data> VirtualFileGist<Data> newVirtualFileGist(@NotNull String id,
                                                         int version,
                                                         @NotNull DataExternalizer<Data> externalizer,
                                                         @NotNull VirtualFileGist.GistCalculator<Data> calcData) {
    if (!ourKnownIds.add(id)) {
      throw new IllegalArgumentException("Gist '" + id + "' is already registered");
    }

    return new VirtualFileGistImpl<>(id, version, externalizer, calcData);
  }

  @NotNull
  @Override
  public <Data> PsiFileGist<Data> newPsiFileGist(@NotNull String id,
                                                 int version,
                                                 @NotNull DataExternalizer<Data> externalizer,
                                                 @NotNull NullableFunction<PsiFile, Data> calculator) {
    return new PsiFileGistImpl<>(id, version, externalizer, calculator);
  }

  int getReindexCount() {
    return myReindexCount.get();
  }

  public void invalidateData() {
    // Clear all cache at once to simplify and speedup this operation.
    // It can be made per-file if cache recalculation ever becomes an issue.
    PropertiesComponent.getInstance().setValue(ourPropertyName, myReindexCount.incrementAndGet(), 0);
  }

  @TestOnly
  public void resetReindexCount() {
    myReindexCount.set(0);
    PropertiesComponent.getInstance().unsetValue(ourPropertyName);
  }
}