chiark - git - ian - stressapptest/blob - src/logger.cc

   1 // Copyright 2009 Google Inc. All Rights Reserved.
   2
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6
   7 //      http://www.apache.org/licenses/LICENSE-2.0
   8
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 #include "logger.h"
  16
  17 #include <pthread.h>
  18 #include <stdarg.h>
  19 #include <stdio.h>
  20 #include <time.h>
  21 #include <unistd.h>
  22
  23 #include <string>
  24 #include <vector>
  25
  26 // This file must work with autoconf on its public version,
  27 // so these includes are correct.
  28 #include "sattypes.h"
  29
  30
  31 Logger *Logger::GlobalLogger() {
  32   static Logger logger;
  33   return &logger;
  34 }
  35
  36 void Logger::VLogF(int priority, const char *format, va_list args) {
  37   if (priority > verbosity_) {
  38     return;
  39   }
  40   char buffer[4096];
  41   size_t length = 0;
  42   if (log_timestamps_) {
  43     time_t raw_time;
  44     time(&raw_time);
  45     struct tm time_struct;
  46     localtime_r(&raw_time, &time_struct);
  47     length = strftime(buffer, sizeof(buffer), "%Y/%m/%d-%H:%M:%S(%Z) ",
  48                       &time_struct);
  49     LOGGER_ASSERT(length);  // Catch if the buffer is set too small.
  50   }
  51   length += vsnprintf(buffer + length, sizeof(buffer) - length, format, args);
  52   if (length >= sizeof(buffer)) {
  53     length = sizeof(buffer);
  54     buffer[sizeof(buffer) - 1] = '\n';
  55   }
  56   QueueLogLine(new string(buffer, length));
  57 }
  58
  59 void Logger::StartThread() {
  60   LOGGER_ASSERT(!thread_running_);
  61   thread_running_ = true;
  62   LOGGER_ASSERT(0 == pthread_create(&thread_, NULL, &StartRoutine, this));
  63 }
  64
  65 void Logger::StopThread() {
  66   // Allow this to be called before the thread has started.
  67   if (!thread_running_) {
  68     return;
  69   }
  70   thread_running_ = false;
  71   int retval = pthread_mutex_lock(&queued_lines_mutex_);
  72   LOGGER_ASSERT(0 == retval);
  73   bool need_cond_signal = queued_lines_.empty();
  74   queued_lines_.push_back(NULL);
  75   retval = pthread_mutex_unlock(&queued_lines_mutex_);
  76   LOGGER_ASSERT(0 == retval);
  77   if (need_cond_signal) {
  78     retval = pthread_cond_signal(&queued_lines_cond_);
  79     LOGGER_ASSERT(0 == retval);
  80   }
  81   retval = pthread_join(thread_, NULL);
  82   LOGGER_ASSERT(0 == retval);
  83 }
  84
  85 Logger::Logger()
  86     : verbosity_(20),
  87       log_fd_(-1),
  88       thread_running_(false),
  89       log_timestamps_(true) {
  90   LOGGER_ASSERT(0 == pthread_mutex_init(&queued_lines_mutex_, NULL));
  91   LOGGER_ASSERT(0 == pthread_cond_init(&queued_lines_cond_, NULL));
  92   LOGGER_ASSERT(0 == pthread_cond_init(&full_queue_cond_, NULL));
  93 }
  94
  95 Logger::~Logger() {
  96   LOGGER_ASSERT(0 == pthread_mutex_destroy(&queued_lines_mutex_));
  97   LOGGER_ASSERT(0 == pthread_cond_destroy(&queued_lines_cond_));
  98   LOGGER_ASSERT(0 == pthread_cond_destroy(&full_queue_cond_));
  99 }
 100
 101 void Logger::QueueLogLine(string *line) {
 102   LOGGER_ASSERT(line != NULL);
 103   LOGGER_ASSERT(0 == pthread_mutex_lock(&queued_lines_mutex_));
 104   if (thread_running_) {
 105     if (queued_lines_.size() >= kMaxQueueSize) {
 106       LOGGER_ASSERT(0 == pthread_cond_wait(&full_queue_cond_,
 107                                            &queued_lines_mutex_));
 108     }
 109     if (queued_lines_.empty()) {
 110       LOGGER_ASSERT(0 == pthread_cond_signal(&queued_lines_cond_));
 111     }
 112     queued_lines_.push_back(line);
 113   } else {
 114     WriteAndDeleteLogLine(line);
 115   }
 116   LOGGER_ASSERT(0 == pthread_mutex_unlock(&queued_lines_mutex_));
 117 }
 118
 119 void Logger::WriteAndDeleteLogLine(string *line) {
 120   LOGGER_ASSERT(line != NULL);
 121   ssize_t bytes_written;
 122   if (log_fd_ >= 0) {
 123     bytes_written = write(log_fd_, line->data(), line->size());
 124     LOGGER_ASSERT(bytes_written == static_cast<ssize_t>(line->size()));
 125   }
 126   bytes_written = write(STDOUT_FILENO, line->data(), line->size());
 127   LOGGER_ASSERT(bytes_written == static_cast<ssize_t>(line->size()));
 128   delete line;
 129 }
 130
 131 void *Logger::StartRoutine(void *ptr) {
 132   Logger *self = static_cast<Logger*>(ptr);
 133   self->ThreadMain();
 134   return NULL;
 135 }
 136
 137 void Logger::ThreadMain() {
 138   vector<string*> local_queue;
 139   LOGGER_ASSERT(0 == pthread_mutex_lock(&queued_lines_mutex_));
 140
 141   for (;;) {
 142     if (queued_lines_.empty()) {
 143       LOGGER_ASSERT(0 == pthread_cond_wait(&queued_lines_cond_,
 144                                            &queued_lines_mutex_));
 145       continue;
 146     }
 147
 148     // We move the log lines into a local queue so we can release the lock
 149     // while writing them to disk, preventing other threads from blocking on
 150     // our writes.
 151     local_queue.swap(queued_lines_);
 152     if (local_queue.size() >= kMaxQueueSize) {
 153       LOGGER_ASSERT(0 == pthread_cond_broadcast(&full_queue_cond_));
 154     }
 155
 156     // Unlock while we process our local queue.
 157     LOGGER_ASSERT(0 == pthread_mutex_unlock(&queued_lines_mutex_));
 158     for (vector<string*>::const_iterator it = local_queue.begin();
 159          it != local_queue.end(); ++it) {
 160       if (*it == NULL) {
 161         // NULL is guaranteed to be at the end.
 162         return;
 163       }
 164       WriteAndDeleteLogLine(*it);
 165     }
 166     local_queue.clear();
 167     // We must hold the lock at the start of each iteration of this for loop.
 168     LOGGER_ASSERT(0 == pthread_mutex_lock(&queued_lines_mutex_));
 169   }
 170 }