code: /**
   * Copyright 2023 Alexey Ragozin
   *
   * 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 org.gridkit.jvmtool.cmd;
  
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.Reader;
  import java.util.Iterator;
  
  import org.gridkit.jvmtool.cli.CommandLauncher;
  import org.gridkit.jvmtool.cli.CommandLauncher.CmdRef;
  import org.gridkit.jvmtool.stacktrace.StackTraceCodec;
  import org.gridkit.jvmtool.stacktrace.StackTraceWriter;
  import org.gridkit.jvmtool.stacktrace.ThreadSnapshot;
  import org.gridkit.jvmtool.stacktrace.util.LinuxPerfImporter;
  
  import com.beust.jcommander.Parameter;
  import com.beust.jcommander.Parameters;
  import com.beust.jcommander.ParametersDelegate;
  
  /**
   * Perf import command.
   *
   * @author Alexey Ragozin (alexey.ragozin@gmail.com)
   */
  public class PerfImportCmd implements CmdRef {
  
      @Override
      public String getCommandName() {
          return "prfi";
      }
  
      @Override
      public Runnable newCommand(CommandLauncher host) {
          return new PrfI(host);
      }
  
      @Parameters(commandDescription = "Pref import")
      public static class PrfI implements Runnable {
  
          @ParametersDelegate
          private CommandLauncher host;
  
          @Parameter(names = {"-i", "--input"}, required = true, description = "Name of file to read perf data, use '-' for stdin")
          private String inputFile;
  
          @Parameter(names = {"-f", "--filter"}, required = false, description = "Event type filter, default - first event type read")
          private String filter = null;
  
          @Parameter(names = {"-o", "--output"}, required = true, description = "Name of file to write thread dump")
          private String outputFile;
  
          @Parameter(names = {"-u", "--upscale"}, required = false, description = "Upscale factor, default 3")
          private double upscale = 3;
  
          private int traceCounter;
          private StackTraceWriter writer;
  
          public PrfI(CommandLauncher host) {
              this.host = host;
          }
  
          @Override
          public void run() {
  
              try {
  
                  openWriter();
  
                  Reader reader;
                  if ("-".equals(inputFile)) {
                      reader = new InputStreamReader(System.in);
                  } else {
                      reader = new FileReader(inputFile);
                  }
  
                  Iterator<ThreadSnapshot> it = LinuxPerfImporter.parseAndConvert(reader, filter, upscale, 0);
  
                  while (it.hasNext()) {
                      ThreadSnapshot event = it.next();
                      writer.write(event);
                      traceCounter++;
                  }
  
                  System.out.println("Produced " + traceCounter + " resampled traces");
                  writer.close();
  
              } catch (Exception e) {
                  host.fail("Unexpected error: " + e.toString(), e);
              }
          }
  
          private void openWriter() throws FileNotFoundException, IOException {
              File file = new File(outputFile);
              if (file.getParentFile() != null) {
                  file.getParentFile().mkdirs();
              }
              writer = StackTraceCodec.newWriter(new FileOutputStream(file));
              System.out.println("Writing to " + file.getAbsolutePath());
          }
      }
  }
  