tor-browser

The Tor Browser
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rtc_event_log_output_file.cc (3195B)

      1 /*
      2 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
      3 *
      4 *  Use of this source code is governed by a BSD-style license
      5 *  that can be found in the LICENSE file in the root of the source
      6 *  tree. An additional intellectual property rights grant can be found
      7 *  in the file PATENTS.  All contributing project authors may
      8 *  be found in the AUTHORS file in the root of the source tree.
      9 */
     10 
     11 #include "api/rtc_event_log_output_file.h"
     12 
     13 #include <cstddef>
     14 #include <cstdio>
     15 #include <limits>
     16 #include <string>
     17 #include <utility>
     18 
     19 #include "absl/strings/string_view.h"
     20 #include "api/rtc_event_log/rtc_event_log.h"
     21 #include "rtc_base/checks.h"
     22 #include "rtc_base/logging.h"
     23 #include "rtc_base/system/file_wrapper.h"
     24 
     25 namespace webrtc {
     26 
     27 // Together with the assumption of no single Write() would ever be called on
     28 // an input with length greater-than-or-equal-to (max(size_t) / 2), this
     29 // guarantees no overflow of the check for remaining file capacity in Write().
     30 // This does *not* apply to files with unlimited size.
     31 const size_t RtcEventLogOutputFile::kMaxReasonableFileSize =
     32    std::numeric_limits<size_t>::max() / 2;
     33 
     34 RtcEventLogOutputFile::RtcEventLogOutputFile(const std::string& file_name)
     35    : RtcEventLogOutputFile(FileWrapper::OpenWriteOnly(file_name),
     36                            RtcEventLog::kUnlimitedOutput) {}
     37 
     38 RtcEventLogOutputFile::RtcEventLogOutputFile(const std::string& file_name,
     39                                             size_t max_size_bytes)
     40 
     41    // Unlike plain fopen, FileWrapper takes care of filename utf8 ->
     42    // wchar conversion on Windows.
     43    : RtcEventLogOutputFile(FileWrapper::OpenWriteOnly(file_name),
     44                            max_size_bytes) {}
     45 
     46 RtcEventLogOutputFile::RtcEventLogOutputFile(FILE* file, size_t max_size_bytes)
     47    : RtcEventLogOutputFile(FileWrapper(file), max_size_bytes) {}
     48 
     49 RtcEventLogOutputFile::RtcEventLogOutputFile(FileWrapper file,
     50                                             size_t max_size_bytes)
     51    : max_size_bytes_(max_size_bytes), file_(std::move(file)) {
     52  RTC_CHECK_LE(max_size_bytes_, kMaxReasonableFileSize);
     53  if (!file_.is_open()) {
     54    RTC_LOG(LS_ERROR) << "Invalid file. WebRTC event log not started.";
     55  }
     56 }
     57 
     58 bool RtcEventLogOutputFile::IsActive() const {
     59  return IsActiveInternal();
     60 }
     61 
     62 bool RtcEventLogOutputFile::Write(absl::string_view output) {
     63  RTC_DCHECK(IsActiveInternal());
     64  // No single write may be so big, that it would risk overflowing the
     65  // calculation of (written_bytes_ + output.length()).
     66  RTC_DCHECK_LT(output.size(), kMaxReasonableFileSize);
     67 
     68  if (max_size_bytes_ == RtcEventLog::kUnlimitedOutput ||
     69      written_bytes_ + output.size() <= max_size_bytes_) {
     70    if (file_.Write(output.data(), output.size())) {
     71      written_bytes_ += output.size();
     72      return true;
     73    } else {
     74      RTC_LOG(LS_ERROR) << "Write to WebRtcEventLog file failed.";
     75    }
     76  } else {
     77    RTC_LOG(LS_VERBOSE) << "Max file size reached.";
     78  }
     79 
     80  // Failed, for one of above reasons. Close output file.
     81  file_.Close();
     82  return false;
     83 }
     84 
     85 // Internal non-virtual method.
     86 bool RtcEventLogOutputFile::IsActiveInternal() const {
     87  return file_.is_open();
     88 }
     89 
     90 }  // namespace webrtc