platform/vcs-log/impl/src/com/intellij/vcs/log/util/StopWatch.java

/*
 * Copyright 2000-2014 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.vcs.log.util;

import com.intellij.openapi.diagnostic.Logger;
import com.intellij.openapi.util.text.StringUtil;
import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.util.Function;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.NotNull;

import java.util.Collection;
import java.util.Map;

public class StopWatch {

  private static final Logger LOG = Logger.getInstance(StopWatch.class);

  private final long myStartTime;
  @NotNull private final String myOperation;
  @NotNull private final Map<VirtualFile, Long> myDurationPerRoot;

  private StopWatch(@NotNull String operation) {
    myOperation = operation;
    myStartTime = System.currentTimeMillis();
    myDurationPerRoot = ContainerUtil.newHashMap();
  }

  @NotNull
  public static StopWatch start(@NotNull String operation) {
    return new StopWatch(operation);
  }

  public void rootCompleted(@NotNull VirtualFile root) {
    long totalDuration = System.currentTimeMillis() - myStartTime;
    long duration = totalDuration - sum(myDurationPerRoot.values());
    myDurationPerRoot.put(root, duration);
  }

  private static long sum(@NotNull Collection<Long> durations) {
    long sum = 0;
    for (Long duration : durations) {
      sum += duration;
    }
    return sum;
  }

  public void report() {
    String message = myOperation + " took " + (System.currentTimeMillis() - myStartTime) + " ms";
    if (myDurationPerRoot.size() > 1) {
      message += "\n" + StringUtil.join(myDurationPerRoot.entrySet(), new Function<Map.Entry<VirtualFile, Long>, String>() {
       @Override
       public String fun(Map.Entry<VirtualFile, Long> entry) {
         return "    " + entry.getKey().getName() + ": " + entry.getValue() + " ms";
       }
     }, "\n");
    }
    LOG.debug(message);
  }

}