third_party/leveldatabase/chromium_logger.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef THIRD_PARTY_LEVELDATABASE_CHROMIUM_LOGGER_H_
   6 #define THIRD_PARTY_LEVELDATABASE_CHROMIUM_LOGGER_H_
   7
   8 #include <stdio.h>
   9
  10 #include <algorithm>
  11
  12 #include "base/format_macros.h"
  13 #include "base/strings/string_util.h"
  14 #include "base/time/time.h"
  15 #include "third_party/leveldatabase/src/include/leveldb/env.h"
  16
  17 namespace leveldb {
  18
  19 class ChromiumLogger : public Logger {
  20  public:
  21   explicit ChromiumLogger(FILE* f) : file_(f) {}
  22   virtual ~ChromiumLogger() {
  23     fclose(file_);
  24   }
  25   virtual void Logv(const char* format, va_list ap) {
  26     const base::PlatformThreadId thread_id =
  27         ::base::PlatformThread::CurrentId();
  28
  29     // We try twice: the first time with a fixed-size stack allocated buffer,
  30     // and the second time with a much larger dynamically allocated buffer.
  31     char buffer[500];
  32     for (int iter = 0; iter < 2; iter++) {
  33       char* base;
  34       int bufsize;
  35       if (iter == 0) {
  36         bufsize = sizeof(buffer);
  37         base = buffer;
  38       } else {
  39         bufsize = 30000;
  40         base = new char[bufsize];
  41       }
  42       char* p = base;
  43       char* limit = base + bufsize;
  44
  45       ::base::Time::Exploded t;
  46       ::base::Time::Now().LocalExplode(&t);
  47
  48       p += ::base::snprintf(p, limit - p,
  49                     "%04d/%02d/%02d-%02d:%02d:%02d.%03d %" PRIu64 " ",
  50                     t.year,
  51                     t.month,
  52                     t.day_of_month,
  53                     t.hour,
  54                     t.minute,
  55                     t.second,
  56                     t.millisecond,
  57                     static_cast<uint64>(thread_id));
  58
  59       // Print the message
  60       if (p < limit) {
  61         va_list backup_ap;
  62         GG_VA_COPY(backup_ap, ap);
  63         p += vsnprintf(p, limit - p, format, backup_ap);
  64         va_end(backup_ap);
  65       }
  66
  67       // Truncate to available space if necessary
  68       if (p >= limit) {
  69         if (iter == 0) {
  70           continue;       // Try again with larger buffer
  71         } else {
  72           p = limit - 1;
  73         }
  74       }
  75
  76       // Add newline if necessary
  77       if (p == base || p[-1] != '\n') {
  78         *p++ = '\n';
  79       }
  80
  81       assert(p <= limit);
  82       fwrite(base, 1, p - base, file_);
  83       fflush(file_);
  84       if (base != buffer) {
  85         delete[] base;
  86       }
  87       break;
  88     }
  89   }
  90
  91  private:
  92   FILE* file_;
  93 };
  94
  95 }  // namespace leveldb
  96
  97 #endif  // THIRD_PARTY_LEVELDATABASE_CHROMIUM_LOGGER_H_