webrtc/base/filerotatingstream.cc - src.git - Git at Google

 /*
  *  Copyright 2015 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 #include "webrtc/base/filerotatingstream.h"

 #include <algorithm>
 #include <iostream>
 #include <string>

 #include "webrtc/base/checks.h"
 #include "webrtc/base/fileutils.h"
 #include "webrtc/base/pathutils.h"

 // Note: We use std::cerr for logging in the write paths of this stream to avoid
 // infinite loops when logging.

 namespace rtc {

 FileRotatingStream::FileRotatingStream(const std::string& dir_path,
                                        const std::string& file_prefix)
     : FileRotatingStream(dir_path, file_prefix, 0, 0, kRead) {
 }

 FileRotatingStream::FileRotatingStream(const std::string& dir_path,
                                        const std::string& file_prefix,
                                        size_t max_file_size,
                                        size_t num_files)
     : FileRotatingStream(dir_path,
                          file_prefix,
                          max_file_size,
                          num_files,
                          kWrite) {
   RTC_DCHECK_GT(max_file_size, 0);
   RTC_DCHECK_GT(num_files, 1);
 }

 FileRotatingStream::FileRotatingStream(const std::string& dir_path,
                                        const std::string& file_prefix,
                                        size_t max_file_size,
                                        size_t num_files,
                                        Mode mode)
     : dir_path_(dir_path),
       file_prefix_(file_prefix),
       mode_(mode),
       file_stream_(nullptr),
       max_file_size_(max_file_size),
       current_file_index_(0),
       rotation_index_(0),
       current_bytes_written_(0),
       disable_buffering_(false) {
   RTC_DCHECK(Filesystem::IsFolder(dir_path));
   switch (mode) {
     case kWrite: {
       file_names_.clear();
       for (size_t i = 0; i < num_files; ++i) {
         file_names_.push_back(GetFilePath(i, num_files));
       }
       rotation_index_ = num_files - 1;
       break;
     }
     case kRead: {
       file_names_ = GetFilesWithPrefix();
       std::sort(file_names_.begin(), file_names_.end());
       if (file_names_.size() > 0) {
         // |file_names_| is sorted newest first, so read from the end.
         current_file_index_ = file_names_.size() - 1;
       }
       break;
     }
   }
 }

 FileRotatingStream::~FileRotatingStream() {
 }

 StreamState FileRotatingStream::GetState() const {
   if (mode_ == kRead && current_file_index_ < file_names_.size()) {
     return SS_OPEN;
   }
   if (!file_stream_) {
     return SS_CLOSED;
   }
   return file_stream_->GetState();
 }

 StreamResult FileRotatingStream::Read(void* buffer,
                                       size_t buffer_len,
                                       size_t* read,
                                       int* error) {
   RTC_DCHECK(buffer);
   if (mode_ != kRead) {
     return SR_EOS;
   }
   if (current_file_index_ >= file_names_.size()) {
     return SR_EOS;
   }
   // We will have no file stream initially, and when we are finished with the
   // previous file.
   if (!file_stream_) {
     if (!OpenCurrentFile()) {
       return SR_ERROR;
     }
   }
   int local_error = 0;
   if (!error) {
     error = &local_error;
   }
   StreamResult result = file_stream_->Read(buffer, buffer_len, read, error);
   if (result == SR_EOS || result == SR_ERROR) {
     if (result == SR_ERROR) {
       LOG(LS_ERROR) << "Failed to read from: "
                     << file_names_[current_file_index_] << "Error: " << error;
     }
     // Reached the end of the file, read next file. If there is an error return
     // the error status but allow for a next read by reading next file.
     CloseCurrentFile();
     if (current_file_index_ == 0) {
       // Just finished reading the last file, signal EOS by setting index.
       current_file_index_ = file_names_.size();
     } else {
       --current_file_index_;
     }
     if (read) {
       *read = 0;
     }
     return result == SR_EOS ? SR_SUCCESS : result;
   } else if (result == SR_SUCCESS) {
     // Succeeded, continue reading from this file.
     return SR_SUCCESS;
   } else {
     RTC_NOTREACHED();
   }
   return result;
 }

 StreamResult FileRotatingStream::Write(const void* data,
                                        size_t data_len,
                                        size_t* written,
                                        int* error) {
   if (mode_ != kWrite) {
     return SR_EOS;
   }
   if (!file_stream_) {
     std::cerr << "Open() must be called before Write." << std::endl;
     return SR_ERROR;
   }
   // Write as much as will fit in to the current file.
   RTC_DCHECK_LT(current_bytes_written_, max_file_size_);
   size_t remaining_bytes = max_file_size_ - current_bytes_written_;
   size_t write_length = std::min(data_len, remaining_bytes);
   size_t local_written = 0;
   if (!written) {
     written = &local_written;
   }
   StreamResult result = file_stream_->Write(data, write_length, written, error);
   current_bytes_written_ += *written;

   // If we're done with this file, rotate it out.
   if (current_bytes_written_ >= max_file_size_) {
     RTC_DCHECK_EQ(current_bytes_written_, max_file_size_);
     RotateFiles();
   }
   return result;
 }

 bool FileRotatingStream::Flush() {
   if (!file_stream_) {
     return false;
   }
   return file_stream_->Flush();
 }

 bool FileRotatingStream::GetSize(size_t* size) const {
   if (mode_ != kRead) {
     // Not possible to get accurate size on disk when writing because of
     // potential buffering.
     return false;
   }
   RTC_DCHECK(size);
   *size = 0;
   size_t total_size = 0;
   for (auto file_name : file_names_) {
     Pathname pathname(file_name);
     size_t file_size = 0;
     if (Filesystem::GetFileSize(file_name, &file_size)) {
       total_size += file_size;
     }
   }
   *size = total_size;
   return true;
 }

 void FileRotatingStream::Close() {
   CloseCurrentFile();
 }

 bool FileRotatingStream::Open() {
   switch (mode_) {
     case kRead:
       // Defer opening to when we first read since we want to return read error
       // if we fail to open next file.
       return true;
     case kWrite: {
       // Delete existing files when opening for write.
       std::vector<std::string> matching_files = GetFilesWithPrefix();
       for (auto matching_file : matching_files) {
         if (!Filesystem::DeleteFile(matching_file)) {
           std::cerr << "Failed to delete: " << matching_file << std::endl;
         }
       }
       return OpenCurrentFile();
     }
   }
   return false;
 }

 bool FileRotatingStream::DisableBuffering() {
   disable_buffering_ = true;
   if (!file_stream_) {
     std::cerr << "Open() must be called before DisableBuffering()."
               << std::endl;
     return false;
   }
   return file_stream_->DisableBuffering();
 }

 std::string FileRotatingStream::GetFilePath(size_t index) const {
   RTC_DCHECK_LT(index, file_names_.size());
   return file_names_[index];
 }

 bool FileRotatingStream::OpenCurrentFile() {
   CloseCurrentFile();

   // Opens the appropriate file in the appropriate mode.
   RTC_DCHECK_LT(current_file_index_, file_names_.size());
   std::string file_path = file_names_[current_file_index_];
   file_stream_.reset(new FileStream());
   const char* mode = nullptr;
   switch (mode_) {
     case kWrite:
       mode = "w+";
       // We should always we writing to the zero-th file.
       RTC_DCHECK_EQ(current_file_index_, 0);
       break;
     case kRead:
       mode = "r";
       break;
   }
   int error = 0;
   if (!file_stream_->Open(file_path, mode, &error)) {
     std::cerr << "Failed to open: " << file_path << "Error: " << error
               << std::endl;
     file_stream_.reset();
     return false;
   }
   if (disable_buffering_) {
     file_stream_->DisableBuffering();
   }
   return true;
 }

 void FileRotatingStream::CloseCurrentFile() {
   if (!file_stream_) {
     return;
   }
   current_bytes_written_ = 0;
   file_stream_.reset();
 }

 void FileRotatingStream::RotateFiles() {
   RTC_DCHECK_EQ(mode_, kWrite);
   CloseCurrentFile();
   // Rotates the files by deleting the file at |rotation_index_|, which is the
   // oldest file and then renaming the newer files to have an incremented index.
   // See header file comments for example.
   RTC_DCHECK_LT(rotation_index_, file_names_.size());
   std::string file_to_delete = file_names_[rotation_index_];
   if (Filesystem::IsFile(file_to_delete)) {
     if (!Filesystem::DeleteFile(file_to_delete)) {
       std::cerr << "Failed to delete: " << file_to_delete << std::endl;
     }
   }
   for (auto i = rotation_index_; i > 0; --i) {
     std::string rotated_name = file_names_[i];
     std::string unrotated_name = file_names_[i - 1];
     if (Filesystem::IsFile(unrotated_name)) {
       if (!Filesystem::MoveFile(unrotated_name, rotated_name)) {
         std::cerr << "Failed to move: " << unrotated_name << " to "
                   << rotated_name << std::endl;
       }
     }
   }
   // Create a new file for 0th index.
   OpenCurrentFile();
   OnRotation();
 }

 std::vector<std::string> FileRotatingStream::GetFilesWithPrefix() const {
   std::vector<std::string> files;
   // Iterate over the files in the directory.
   DirectoryIterator it;
   Pathname dir_path;
   dir_path.SetFolder(dir_path_);
   if (!it.Iterate(dir_path)) {
     return files;
   }
   do {
     std::string current_name = it.Name();
     if (current_name.size() && !it.IsDirectory() &&
         current_name.compare(0, file_prefix_.size(), file_prefix_) == 0) {
       Pathname path(dir_path_, current_name);
       files.push_back(path.pathname());
     }
   } while (it.Next());
   return files;
 }

 std::string FileRotatingStream::GetFilePath(size_t index,
                                             size_t num_files) const {
   RTC_DCHECK_LT(index, num_files);
   std::ostringstream file_name;
   // The format will be "_%<num_digits>zu". We want to zero pad the index so
   // that it will sort nicely.
   size_t max_digits = ((num_files - 1) / 10) + 1;
   size_t num_digits = (index / 10) + 1;
   RTC_DCHECK_LE(num_digits, max_digits);
   size_t padding = max_digits - num_digits;

   file_name << file_prefix_ << "_";
   for (size_t i = 0; i < padding; ++i) {
     file_name << "0";
   }
   file_name << index;

   Pathname file_path(dir_path_, file_name.str());
   return file_path.pathname();
 }

 CallSessionFileRotatingStream::CallSessionFileRotatingStream(
     const std::string& dir_path)
     : FileRotatingStream(dir_path, kLogPrefix),
       max_total_log_size_(0),
       num_rotations_(0) {
 }

 CallSessionFileRotatingStream::CallSessionFileRotatingStream(
     const std::string& dir_path,
     size_t max_total_log_size)
     : FileRotatingStream(dir_path,
                          kLogPrefix,
                          max_total_log_size / 2,
                          GetNumRotatingLogFiles(max_total_log_size) + 1),
       max_total_log_size_(max_total_log_size),
       num_rotations_(0) {
   RTC_DCHECK_GE(max_total_log_size, 4);
 }

 const char* CallSessionFileRotatingStream::kLogPrefix = "webrtc_log";
 const size_t CallSessionFileRotatingStream::kRotatingLogFileDefaultSize =
     1024 * 1024;

 void CallSessionFileRotatingStream::OnRotation() {
   ++num_rotations_;
   if (num_rotations_ == 1) {
     // On the first rotation adjust the max file size so subsequent files after
     // the first are smaller.
     SetMaxFileSize(GetRotatingLogSize(max_total_log_size_));
   } else if (num_rotations_ == (GetNumFiles() - 1)) {
     // On the next rotation the very first file is going to be deleted. Change
     // the rotation index so this doesn't happen.
     SetRotationIndex(GetRotationIndex() - 1);
   }
 }

 size_t CallSessionFileRotatingStream::GetRotatingLogSize(
     size_t max_total_log_size) {
   size_t num_rotating_log_files = GetNumRotatingLogFiles(max_total_log_size);
   size_t rotating_log_size = num_rotating_log_files > 2
                                  ? kRotatingLogFileDefaultSize
                                  : max_total_log_size / 4;
   return rotating_log_size;
 }

 size_t CallSessionFileRotatingStream::GetNumRotatingLogFiles(
     size_t max_total_log_size) {
   // At minimum have two rotating files. Otherwise split the available log size
   // evenly across 1MB files.
   return std::max((size_t)2,
                   (max_total_log_size / 2) / kRotatingLogFileDefaultSize);
 }

 }  // namespace rtc
	/*
	* Copyright 2015 The WebRTC Project Authors. All rights reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	#include "webrtc/base/filerotatingstream.h"

	#include <algorithm>
	#include <iostream>
	#include <string>

	#include "webrtc/base/checks.h"
	#include "webrtc/base/fileutils.h"
	#include "webrtc/base/pathutils.h"

	// Note: We use std::cerr for logging in the write paths of this stream to avoid
	// infinite loops when logging.

	namespace rtc {

	FileRotatingStream::FileRotatingStream(const std::string& dir_path,
	const std::string& file_prefix)
	: FileRotatingStream(dir_path, file_prefix, 0, 0, kRead) {
	}

	FileRotatingStream::FileRotatingStream(const std::string& dir_path,
	const std::string& file_prefix,
	size_t max_file_size,
	size_t num_files)
	: FileRotatingStream(dir_path,
	file_prefix,
	max_file_size,
	num_files,
	kWrite) {
	RTC_DCHECK_GT(max_file_size, 0);
	RTC_DCHECK_GT(num_files, 1);
	}

	FileRotatingStream::FileRotatingStream(const std::string& dir_path,
	const std::string& file_prefix,
	size_t max_file_size,
	size_t num_files,
	Mode mode)
	: dir_path_(dir_path),
	file_prefix_(file_prefix),
	mode_(mode),
	file_stream_(nullptr),
	max_file_size_(max_file_size),
	current_file_index_(0),
	rotation_index_(0),
	current_bytes_written_(0),
	disable_buffering_(false) {
	RTC_DCHECK(Filesystem::IsFolder(dir_path));
	switch (mode) {
	case kWrite: {
	file_names_.clear();
	for (size_t i = 0; i < num_files; ++i) {
	file_names_.push_back(GetFilePath(i, num_files));
	}
	rotation_index_ = num_files - 1;
	break;
	}
	case kRead: {
	file_names_ = GetFilesWithPrefix();
	std::sort(file_names_.begin(), file_names_.end());
	if (file_names_.size() > 0) {
	// \|file_names_\| is sorted newest first, so read from the end.
	current_file_index_ = file_names_.size() - 1;
	}
	break;
	}
	}
	}

	FileRotatingStream::~FileRotatingStream() {
	}

	StreamState FileRotatingStream::GetState() const {
	if (mode_ == kRead && current_file_index_ < file_names_.size()) {
	return SS_OPEN;
	}
	if (!file_stream_) {
	return SS_CLOSED;
	}
	return file_stream_->GetState();
	}

	StreamResult FileRotatingStream::Read(void* buffer,
	size_t buffer_len,
	size_t* read,
	int* error) {
	RTC_DCHECK(buffer);
	if (mode_ != kRead) {
	return SR_EOS;
	}
	if (current_file_index_ >= file_names_.size()) {
	return SR_EOS;
	}
	// We will have no file stream initially, and when we are finished with the
	// previous file.
	if (!file_stream_) {
	if (!OpenCurrentFile()) {
	return SR_ERROR;
	}
	}
	int local_error = 0;
	if (!error) {
	error = &local_error;
	}
	StreamResult result = file_stream_->Read(buffer, buffer_len, read, error);
	if (result == SR_EOS \|\| result == SR_ERROR) {
	if (result == SR_ERROR) {
	LOG(LS_ERROR) << "Failed to read from: "
	<< file_names_[current_file_index_] << "Error: " << error;
	}
	// Reached the end of the file, read next file. If there is an error return
	// the error status but allow for a next read by reading next file.
	CloseCurrentFile();
	if (current_file_index_ == 0) {
	// Just finished reading the last file, signal EOS by setting index.
	current_file_index_ = file_names_.size();
	} else {
	--current_file_index_;
	}
	if (read) {
	*read = 0;
	}
	return result == SR_EOS ? SR_SUCCESS : result;
	} else if (result == SR_SUCCESS) {
	// Succeeded, continue reading from this file.
	return SR_SUCCESS;
	} else {
	RTC_NOTREACHED();
	}
	return result;
	}

	StreamResult FileRotatingStream::Write(const void* data,
	size_t data_len,
	size_t* written,
	int* error) {
	if (mode_ != kWrite) {
	return SR_EOS;
	}
	if (!file_stream_) {
	std::cerr << "Open() must be called before Write." << std::endl;
	return SR_ERROR;
	}
	// Write as much as will fit in to the current file.
	RTC_DCHECK_LT(current_bytes_written_, max_file_size_);
	size_t remaining_bytes = max_file_size_ - current_bytes_written_;
	size_t write_length = std::min(data_len, remaining_bytes);
	size_t local_written = 0;
	if (!written) {
	written = &local_written;
	}
	StreamResult result = file_stream_->Write(data, write_length, written, error);
	current_bytes_written_ += *written;

	// If we're done with this file, rotate it out.
	if (current_bytes_written_ >= max_file_size_) {
	RTC_DCHECK_EQ(current_bytes_written_, max_file_size_);
	RotateFiles();
	}
	return result;
	}

	bool FileRotatingStream::Flush() {
	if (!file_stream_) {
	return false;
	}
	return file_stream_->Flush();
	}

	bool FileRotatingStream::GetSize(size_t* size) const {
	if (mode_ != kRead) {
	// Not possible to get accurate size on disk when writing because of
	// potential buffering.
	return false;
	}
	RTC_DCHECK(size);
	*size = 0;
	size_t total_size = 0;
	for (auto file_name : file_names_) {
	Pathname pathname(file_name);
	size_t file_size = 0;
	if (Filesystem::GetFileSize(file_name, &file_size)) {
	total_size += file_size;
	}
	}
	*size = total_size;
	return true;
	}

	void FileRotatingStream::Close() {
	CloseCurrentFile();
	}

	bool FileRotatingStream::Open() {
	switch (mode_) {
	case kRead:
	// Defer opening to when we first read since we want to return read error
	// if we fail to open next file.
	return true;
	case kWrite: {
	// Delete existing files when opening for write.
	std::vector<std::string> matching_files = GetFilesWithPrefix();
	for (auto matching_file : matching_files) {
	if (!Filesystem::DeleteFile(matching_file)) {
	std::cerr << "Failed to delete: " << matching_file << std::endl;
	}
	}
	return OpenCurrentFile();
	}
	}
	return false;
	}

	bool FileRotatingStream::DisableBuffering() {
	disable_buffering_ = true;
	if (!file_stream_) {
	std::cerr << "Open() must be called before DisableBuffering()."
	<< std::endl;
	return false;
	}
	return file_stream_->DisableBuffering();
	}

	std::string FileRotatingStream::GetFilePath(size_t index) const {
	RTC_DCHECK_LT(index, file_names_.size());
	return file_names_[index];
	}

	bool FileRotatingStream::OpenCurrentFile() {
	CloseCurrentFile();

	// Opens the appropriate file in the appropriate mode.
	RTC_DCHECK_LT(current_file_index_, file_names_.size());
	std::string file_path = file_names_[current_file_index_];
	file_stream_.reset(new FileStream());
	const char* mode = nullptr;
	switch (mode_) {
	case kWrite:
	mode = "w+";
	// We should always we writing to the zero-th file.
	RTC_DCHECK_EQ(current_file_index_, 0);
	break;
	case kRead:
	mode = "r";
	break;
	}
	int error = 0;
	if (!file_stream_->Open(file_path, mode, &error)) {
	std::cerr << "Failed to open: " << file_path << "Error: " << error
	<< std::endl;
	file_stream_.reset();
	return false;
	}
	if (disable_buffering_) {
	file_stream_->DisableBuffering();
	}
	return true;
	}

	void FileRotatingStream::CloseCurrentFile() {
	if (!file_stream_) {
	return;
	}
	current_bytes_written_ = 0;
	file_stream_.reset();
	}

	void FileRotatingStream::RotateFiles() {
	RTC_DCHECK_EQ(mode_, kWrite);
	CloseCurrentFile();
	// Rotates the files by deleting the file at \|rotation_index_\|, which is the
	// oldest file and then renaming the newer files to have an incremented index.
	// See header file comments for example.
	RTC_DCHECK_LT(rotation_index_, file_names_.size());
	std::string file_to_delete = file_names_[rotation_index_];
	if (Filesystem::IsFile(file_to_delete)) {
	if (!Filesystem::DeleteFile(file_to_delete)) {
	std::cerr << "Failed to delete: " << file_to_delete << std::endl;
	}
	}
	for (auto i = rotation_index_; i > 0; --i) {
	std::string rotated_name = file_names_[i];
	std::string unrotated_name = file_names_[i - 1];
	if (Filesystem::IsFile(unrotated_name)) {
	if (!Filesystem::MoveFile(unrotated_name, rotated_name)) {
	std::cerr << "Failed to move: " << unrotated_name << " to "
	<< rotated_name << std::endl;
	}
	}
	}
	// Create a new file for 0th index.
	OpenCurrentFile();
	OnRotation();
	}

	std::vector<std::string> FileRotatingStream::GetFilesWithPrefix() const {
	std::vector<std::string> files;
	// Iterate over the files in the directory.
	DirectoryIterator it;
	Pathname dir_path;
	dir_path.SetFolder(dir_path_);
	if (!it.Iterate(dir_path)) {
	return files;
	}
	do {
	std::string current_name = it.Name();
	if (current_name.size() && !it.IsDirectory() &&
	current_name.compare(0, file_prefix_.size(), file_prefix_) == 0) {
	Pathname path(dir_path_, current_name);
	files.push_back(path.pathname());
	}
	} while (it.Next());
	return files;
	}

	std::string FileRotatingStream::GetFilePath(size_t index,
	size_t num_files) const {
	RTC_DCHECK_LT(index, num_files);
	std::ostringstream file_name;
	// The format will be "_%<num_digits>zu". We want to zero pad the index so
	// that it will sort nicely.
	size_t max_digits = ((num_files - 1) / 10) + 1;
	size_t num_digits = (index / 10) + 1;
	RTC_DCHECK_LE(num_digits, max_digits);
	size_t padding = max_digits - num_digits;

	file_name << file_prefix_ << "_";
	for (size_t i = 0; i < padding; ++i) {
	file_name << "0";
	}
	file_name << index;

	Pathname file_path(dir_path_, file_name.str());
	return file_path.pathname();
	}

	CallSessionFileRotatingStream::CallSessionFileRotatingStream(
	const std::string& dir_path)
	: FileRotatingStream(dir_path, kLogPrefix),
	max_total_log_size_(0),
	num_rotations_(0) {
	}

	CallSessionFileRotatingStream::CallSessionFileRotatingStream(
	const std::string& dir_path,
	size_t max_total_log_size)
	: FileRotatingStream(dir_path,
	kLogPrefix,
	max_total_log_size / 2,
	GetNumRotatingLogFiles(max_total_log_size) + 1),
	max_total_log_size_(max_total_log_size),
	num_rotations_(0) {
	RTC_DCHECK_GE(max_total_log_size, 4);
	}

	const char* CallSessionFileRotatingStream::kLogPrefix = "webrtc_log";
	const size_t CallSessionFileRotatingStream::kRotatingLogFileDefaultSize =
	1024 * 1024;

	void CallSessionFileRotatingStream::OnRotation() {
	++num_rotations_;
	if (num_rotations_ == 1) {
	// On the first rotation adjust the max file size so subsequent files after
	// the first are smaller.
	SetMaxFileSize(GetRotatingLogSize(max_total_log_size_));
	} else if (num_rotations_ == (GetNumFiles() - 1)) {
	// On the next rotation the very first file is going to be deleted. Change
	// the rotation index so this doesn't happen.
	SetRotationIndex(GetRotationIndex() - 1);
	}
	}

	size_t CallSessionFileRotatingStream::GetRotatingLogSize(
	size_t max_total_log_size) {
	size_t num_rotating_log_files = GetNumRotatingLogFiles(max_total_log_size);
	size_t rotating_log_size = num_rotating_log_files > 2
	? kRotatingLogFileDefaultSize
	: max_total_log_size / 4;
	return rotating_log_size;
	}

	size_t CallSessionFileRotatingStream::GetNumRotatingLogFiles(
	size_t max_total_log_size) {
	// At minimum have two rotating files. Otherwise split the available log size
	// evenly across 1MB files.
	return std::max((size_t)2,
	(max_total_log_size / 2) / kRotatingLogFileDefaultSize);
	}

	} // namespace rtc