1/*
2 * Copyright (C) 2014 Google Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.caliper.runner;
18
19import static com.google.common.base.Preconditions.checkState;
20
21import com.google.caliper.runner.TrialOutputFactory.FileAndWriter;
22
23import java.io.Closeable;
24import java.io.File;
25import java.io.IOException;
26import java.io.PrintWriter;
27import java.util.UUID;
28
29import javax.annotation.concurrent.GuardedBy;
30import javax.inject.Inject;
31
32/**
33 * A logger to write trial output to a file.
34 */
35@TrialScoped final class TrialOutputLogger implements Closeable {
36  @GuardedBy("this")
37  private File file;
38
39  @GuardedBy("this")
40  private PrintWriter writer;
41
42  private final int trialNumber;
43  private final Experiment experiment;
44  private final UUID trialId;
45  private final TrialOutputFactory outputManager;
46
47  @Inject TrialOutputLogger(TrialOutputFactory outputManager, @TrialNumber int trialNumber,
48      @TrialId UUID trialId, Experiment experiment) {
49    this.outputManager = outputManager;
50    this.trialNumber = trialNumber;
51    this.trialId = trialId;
52    this.experiment = experiment;
53  }
54
55  /** Opens the trial output file. */
56  synchronized void open() throws IOException {
57    if (writer == null) {
58      FileAndWriter fileAndWriter = outputManager.getTrialOutputFile(trialNumber);
59      file = fileAndWriter.file;
60      writer = fileAndWriter.writer;
61    }
62  }
63
64  /**
65   * Ensures that the writer has been opened. also creates a happens-before edge that ensures that
66   * writer is visible (and non-null) after a non-exceptional return from this method.
67   */
68  private synchronized void checkOpened() {
69    checkState(writer != null, "The logger is not open");
70  }
71
72  /** Prints header information to the file. */
73  synchronized void printHeader() {
74    checkOpened();
75    // make the file self describing
76    // TODO(lukes): we could print the command line here.  The user wouldn't be able to run it again
77    // since there would be no runner sending continue messages, but it might be useful to debug
78    // classpath issues.
79    writer.println("Trial Number: " + trialNumber);
80    writer.println("Trial Id: " + trialId);
81    writer.println("Experiment: " + experiment);
82    writer.println();
83  }
84
85  /**
86   * Logs a line of output to the logger.
87   *
88   * @param source The source of the line (e.g. 'stderr')
89   * @param line The output
90   */
91  synchronized void log(String source, String line) {
92    checkOpened();
93    writer.printf("[%s] %s%n", source, line);
94  }
95
96  @Override public synchronized void close() {
97    if (writer != null) {
98      writer.close();
99    }
100  }
101
102  /** Marks the log file so that it will not be deleted at the end of the benchmark. */
103  synchronized void ensureFileIsSaved() {
104    checkOpened();
105    outputManager.persistFile(file);
106  }
107
108  /** Returns the log file path. */
109  synchronized File trialOutputFile() {
110    checkOpened();
111    return file;
112  }
113}
114