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sequence_manager.cc
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sequence_manager.cc
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//
// Durbatuluk is Copyright (c) 2012 Joel Odom
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#include "utils.h"
#include "durbatuluk.pb.h"
#include "sequence_manager.h"
#include "configuration_manager.h"
#include "logger.h"
#include <fstream>
/*static*/ unsigned long long SequenceManager::GetNextSequenceNumber()
{
// reasonable implementation for now
// Will fail if more than one message per second is generated and
// may cause problems if clients clock incorrect.
// !
// !If I change this, I have to change ResetSequenceNumberFile!
// !
return (unsigned long long)time(nullptr);
}
/*static*/ bool SequenceManager::IsSequenceNumberAllowed(
const unsigned long long n)
{
unsigned long long minimum;
std::set<unsigned long long> allowed_numbers;
// read the sequence number file
if (!ReadSequenceNumberFile(&minimum, &allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "ReadSequenceNumberFile failed");
return false; // disallowed
}
// logging
std::stringstream ss;
ss << "N: " << n << " minimum: " << minimum;
Logger::LogMessage(DEBUG, "SequenceManager", &ss);
// check the set of explicitly allowed numbers
if (allowed_numbers.find(n) != allowed_numbers.end())
return true; // allowed
return n >= minimum;
}
/*static*/ bool SequenceManager::SetMinimumAllowedSequenceNumber(
const unsigned long long n)
{
unsigned long long minimum;
std::set<unsigned long long> allowed_numbers;
// read the sequence number file
if (!ReadSequenceNumberFile(&minimum, &allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "ReadSequenceNumberFile failed");
return false; // failure
}
// write the new sequence number file with the new minimum
if (!SequenceManager::WriteSequenceNumberFile(n, allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "WriteSequenceNumberFile failed");
return false; // failure
}
return true; // success
}
/*static*/ bool SequenceManager::AddToAllowedSequenceNumbers(
const unsigned long long n)
{
unsigned long long minimum;
std::set<unsigned long long> allowed_numbers;
// read the sequence number file
if (!ReadSequenceNumberFile(&minimum, &allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "ReadSequenceNumberFile failed");
return false; // failure
}
// add the new number
std::pair<std::set<unsigned long long>::iterator, bool> pair
= allowed_numbers.insert(n);
// write the new sequence number file if it changed
if (pair.second)
{
if (!SequenceManager::WriteSequenceNumberFile(minimum, allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "WriteSequenceNumberFile failed");
return false; // failure
}
}
return true; // success
}
/*static*/ bool SequenceManager::RemoveFromAllowedSequenceNumbers(
const unsigned long long n)
{
unsigned long long minimum;
std::set<unsigned long long> allowed_numbers;
// read the sequence number file
if (!ReadSequenceNumberFile(&minimum, &allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "ReadSequenceNumberFile failed");
return false; // failure
}
// remove the disallowed number
if (allowed_numbers.erase(n) == 1)
{
// write the new sequence number file if it changed
if (!SequenceManager::WriteSequenceNumberFile(minimum, allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "WriteSequenceNumberFile failed");
return false; // failure
}
}
return true; // success
}
/*static*/ bool SequenceManager::ResetSequenceNumberFile()
{
std::set<unsigned long long> allowed_numbers;
if (!SequenceManager::WriteSequenceNumberFile(
SequenceManager::GetNextSequenceNumber(), allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "WriteSequenceNumberFile failed");
return false; // failure
}
return true; // success
}
/*static*/ bool SequenceManager::ReadSequenceNumberFile(
unsigned long long* minimum,
std::set<unsigned long long>* allowed_numbers)
{
// defaults for failure or for writing new file
*minimum = SEQUENCE_NUMBER_MAX;
allowed_numbers->clear();
// get the sequence file name
std::string sequence_file_name;
if (!ConfigurationManager::GetSequenceNumberFileName(&sequence_file_name))
{
Logger::LogMessage(ERROR,
"SequenceManager", "GetSequenceNumberFileName failed");
return false; // failure
}
// attempt to read the sequence file
std::ifstream in_file;
AllowedSequenceNumbers allowed_numbers_message;
std::ios_base::iostate state_before = in_file.exceptions();
in_file.exceptions(std::ios::failbit); // throw on failure
try
{
in_file.open(sequence_file_name, std::ios_base::in);
}
catch (const std::exception& ex)
{
std::stringstream ss;
ss << "Failed to open sequence number file (message " << ex.what()
<< "). Creating new file.";
Logger::LogMessage(INFO, "SequenceManager", &ss);
// writes using defaults
if (!SequenceManager::WriteSequenceNumberFile(
*minimum, *allowed_numbers))
{
Logger::LogMessage(ERROR,
"SequenceManager", "WriteSequenceNumberFile failed");
return false; // failure
}
Logger::LogMessage(DEBUG, "SequenceManager",
"New sequence file created.");
return true; // success
}
in_file.exceptions(state_before); // reset to no throw
if (!allowed_numbers_message.ParseFromIstream(&in_file))
{
Logger::LogMessage(DEBUG, "SequenceManager", "ParseFromIstream failed");
return false; // failure
}
in_file.close(); // does ParseFromIstream close in_file?
// set returns
*minimum = allowed_numbers_message.has_minimum()
? allowed_numbers_message.minimum() : SEQUENCE_NUMBER_MAX;
for (int i = 0; i < allowed_numbers_message.allowed_size(); i++)
allowed_numbers->insert(allowed_numbers_message.allowed(i));
return true; // success
}
/*static*/ bool SequenceManager::WriteSequenceNumberFile(
const unsigned long long minimum,
const std::set<unsigned long long>& allowed_numbers)
{
// get the sequence file name
std::string sequence_file_name;
if (!ConfigurationManager::GetSequenceNumberFileName(&sequence_file_name))
{
Logger::LogMessage(ERROR,
"SequenceManager", "GetSequenceNumberFileName failed");
return false; // failure
}
// build the message to save
AllowedSequenceNumbers allowed_numbers_message;
allowed_numbers_message.set_minimum(minimum);
for (auto it = allowed_numbers.begin(); it != allowed_numbers.end(); it++)
allowed_numbers_message.add_allowed(*it);
// serialize the message to save
std::string serialized;
if (!allowed_numbers_message.SerializeToString(&serialized))
{
Logger::LogMessage(ERROR, "SequenceManager", "SerializeToString failed");
return false; // failure
}
// save
if (!Utils::WriteToFile(sequence_file_name, serialized))
{
Logger::LogMessage(ERROR, "SequenceManager", "WriteToFile failed");
return false; // failure
}
return true; // success
}