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ConfigHandler.cpp
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ConfigHandler.cpp
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/* This file is part of the Spring engine (GPL v2 or later), see LICENSE.html */
#include "ConfigHandler.h"
#include "ConfigLocater.h"
#include "ConfigSource.h"
#include "System/Util.h"
#include "System/Log/ILog.h"
#include "System/Threading/SpringThreading.h"
#ifdef WIN32
#include <io.h>
#endif
#include <stdio.h>
#include <string.h>
#include <list>
#include <stdexcept>
/******************************************************************************/
using std::list;
using std::map;
using std::string;
using std::vector;
typedef map<string, string> StringMap;
ConfigHandler* configHandler = NULL;
/******************************************************************************/
class ConfigHandlerImpl : public ConfigHandler
{
public:
ConfigHandlerImpl(const vector<string>& locations, const bool safemode);
~ConfigHandlerImpl();
void SetString(const string& key, const string& value, bool useOverlay);
string GetString(const string& key) const;
bool IsSet(const string& key) const;
bool IsReadOnly(const string& key) const;
void Delete(const string& key);
string GetConfigFile() const;
const StringMap GetData() const;
StringMap GetDataWithoutDefaults() const;
void Update();
void EnableWriting(bool write) { writingEnabled = write; }
protected:
struct NamedConfigNotifyCallback {
NamedConfigNotifyCallback(ConfigNotifyCallback c, void* h)
: callback(c)
, holder(h)
{}
ConfigNotifyCallback callback;
void* holder;
};
protected:
void AddObserver(ConfigNotifyCallback observer, void* holder);
void RemoveObserver(void* holder);
private:
void RemoveDefaults();
OverlayConfigSource* overlay;
FileConfigSource* writableSource;
vector<ReadOnlyConfigSource*> sources;
// observer related
list<NamedConfigNotifyCallback> observers;
spring::mutex observerMutex;
StringMap changedValues;
bool writingEnabled;
};
/******************************************************************************/
#define for_each_source(it) \
for (vector<ReadOnlyConfigSource*>::iterator it = sources.begin(); it != sources.end(); ++it)
#define for_each_source_const(it) \
for (vector<ReadOnlyConfigSource*>::const_iterator it = sources.begin(); it != sources.end(); ++it)
/**
* @brief Fills the list of sources based on locations.
*
* Sources at lower indices take precedence over sources at higher indices.
* First there is the overlay, then one or more file sources, and the last
* source(s) specify default values.
*/
ConfigHandlerImpl::ConfigHandlerImpl(const vector<string>& locations, const bool safemode)
{
writingEnabled = true;
overlay = new OverlayConfigSource();
writableSource = new FileConfigSource(locations.front());
size_t sources_num = 3;
sources_num += (safemode) ? 1 : 0;
sources_num += locations.size() - 1;
#ifdef DEDICATED
sources_num++;
#endif
#ifdef HEADLESS
sources_num++;
#endif
sources.reserve(sources_num);
sources.push_back(overlay);
if (safemode) {
sources.push_back(new SafemodeConfigSource());
}
sources.push_back(writableSource);
vector<string>::const_iterator loc = locations.begin();
++loc; // skip writableSource
for (; loc != locations.end(); ++loc) {
sources.push_back(new FileConfigSource(*loc));
}
#ifdef DEDICATED
sources.push_back(new DedicatedConfigSource());
#endif
#ifdef HEADLESS
sources.push_back(new HeadlessConfigSource());
#endif
sources.push_back(new DefaultConfigSource());
assert(sources.size() <= sources_num);
// Perform migrations that need to happen on every load.
RemoveDefaults();
}
ConfigHandlerImpl::~ConfigHandlerImpl()
{
assert(observers.empty()); //all observers have to be deregistered by RemoveObserver()
for_each_source(it) {
delete (*it);
}
}
/**
* @brief Remove config variables that are set to their default value.
*
* Algorithm is as follows:
*
* 1) Take all defaults from the DefaultConfigSource
* 2) Go in reverse through the FileConfigSources
* 3) For each one:
* 3a) delete setting if equal to the one in `defaults'
* 3b) add new value to `defaults' if different
*/
void ConfigHandlerImpl::RemoveDefaults()
{
StringMap defaults = sources.back()->GetData();
vector<ReadOnlyConfigSource*>::const_reverse_iterator rsource = sources.rbegin();
for (; rsource != sources.rend(); ++rsource) {
FileConfigSource* source = dynamic_cast<FileConfigSource*> (*rsource);
if (source != NULL) {
// Copy the map; we modify the original while iterating over the copy.
StringMap file = source->GetData();
for (StringMap::const_iterator it = file.begin(); it != file.end(); ++it) {
// Does the key exist in `defaults'?
StringMap::const_iterator pos = defaults.find(it->first);
if (pos != defaults.end() && pos->second == it->second) {
// Exists and value is equal => Delete.
source->Delete(it->first);
}
else {
// Doesn't exist or is not equal => Store new default.
// (It will be the default for the next FileConfigSource.)
defaults[it->first] = it->second;
}
}
}
}
}
StringMap ConfigHandlerImpl::GetDataWithoutDefaults() const
{
StringMap cleanConfig;
StringMap defaults = sources.back()->GetData();
for (auto rsource = sources.crbegin(); rsource != sources.crend(); ++rsource) {
const FileConfigSource* source = dynamic_cast<const FileConfigSource*> (*rsource);
if (source == nullptr) continue;
// Copy the map; we modify the original while iterating over the copy.
StringMap file = source->GetData();
for (auto it = file.cbegin(); it != file.cend(); ++it) {
const auto pos = defaults.find(it->first);
if (pos != defaults.end() && pos->second == it->second)
continue;
cleanConfig[it->first] = it->second;
}
}
return cleanConfig;
}
void ConfigHandlerImpl::Delete(const string& key)
{
for_each_source(it) {
// The alternative to the dynamic cast is to merge ReadWriteConfigSource
// with ReadOnlyConfigSource, but then DefaultConfigSource would have to
// violate Liskov Substitution Principle... (by blocking modifications)
ReadWriteConfigSource* rwcs = dynamic_cast<ReadWriteConfigSource*> (*it);
if (rwcs != NULL) {
rwcs->Delete(key);
}
}
}
bool ConfigHandlerImpl::IsSet(const string& key) const
{
for_each_source_const(it) {
if ((*it)->IsSet(key)) {
return true;
}
}
return false;
}
bool ConfigHandlerImpl::IsReadOnly(const string& key) const
{
const ConfigVariableMetaData* meta = ConfigVariable::GetMetaData(key);
if (meta==NULL) {
return false;
}
return meta->GetReadOnly().Get();
}
string ConfigHandlerImpl::GetString(const string& key) const
{
const ConfigVariableMetaData* meta = ConfigVariable::GetMetaData(key);
for_each_source_const(it) {
if ((*it)->IsSet(key)) {
std::string value = (*it)->GetString(key);
if (meta != NULL) {
value = meta->Clamp(value);
}
return value;
}
}
throw std::runtime_error("ConfigHandler: Error: Key does not exist: " + key +
"\nPlease add the key to the list of allowed configuration values.");
}
/**
* @brief Sets a config string
*
* This does:
* 1) Lock file.
* 2) Read file (in case another program modified something)
* 3) Set data[key] = value.
* 4) Write file (so we keep the settings in the event of a crash or error)
* 5) Unlock file.
*
* We do not want conflicts when multiple instances are running
* at the same time (which would cause data loss).
* This would happen if e.g. unitsync and spring would access
* the config file at the same time, if we would not lock.
*/
void ConfigHandlerImpl::SetString(const string& key, const string& value, bool useOverlay)
{
// if we set something to be persisted,
// we do want to override the overlay value
if (!useOverlay) {
overlay->Delete(key);
}
// Don't do anything if value didn't change.
if (IsSet(key) && GetString(key) == value) {
return;
}
if (useOverlay) {
overlay->SetString(key, value);
}
else if (writingEnabled) {
vector<ReadOnlyConfigSource*>::const_iterator it = sources.begin();
bool deleted = false;
++it; // skip overlay
++it; // skip writableSource
for (; it != sources.end(); ++it) {
if ((*it)->IsSet(key)) {
if ((*it)->GetString(key) == value) {
// key is being set to the default value,
// delete the key instead of setting it.
writableSource->Delete(key);
deleted = true;
}
break;
}
}
if (!deleted) {
// set key to the specified non-default value
writableSource->SetString(key, value);
}
}
std::lock_guard<spring::mutex> lck(observerMutex);
changedValues[key] = value;
}
void ConfigHandlerImpl::Update()
{
std::lock_guard<spring::mutex> lck(observerMutex);
for (StringMap::const_iterator ut = changedValues.begin(); ut != changedValues.end(); ++ut) {
const string& key = ut->first;
const string& value = ut->second;
for (list<NamedConfigNotifyCallback>::const_iterator it = observers.begin(); it != observers.end(); ++it) {
(it->callback)(key, value);
}
}
changedValues.clear();
}
string ConfigHandlerImpl::GetConfigFile() const {
return writableSource->GetFilename();
}
const StringMap ConfigHandlerImpl::GetData() const {
StringMap data;
for_each_source_const(it) {
const StringMap& sourceData = (*it)->GetData();
// insert doesn't overwrite, so this preserves correct overrides
data.insert(sourceData.begin(), sourceData.end());
}
return data;
}
void ConfigHandlerImpl::AddObserver(ConfigNotifyCallback observer, void* holder) {
std::lock_guard<spring::mutex> lck(observerMutex);
observers.emplace_back(observer, holder);
}
void ConfigHandlerImpl::RemoveObserver(void* holder) {
std::lock_guard<spring::mutex> lck(observerMutex);
for (list<NamedConfigNotifyCallback>::iterator it = observers.begin(); it != observers.end(); ++it) {
if (it->holder == holder) {
observers.erase(it);
return;
}
}
}
/******************************************************************************/
void ConfigHandler::Instantiate(const std::string configSource, const bool safemode)
{
Deallocate();
vector<string> locations;
if (!configSource.empty()) {
locations.push_back(configSource);
} else {
ConfigLocater::GetDefaultLocations(locations);
}
assert(!locations.empty());
// log here so unitsync shows configuration source(s), too
vector<string>::const_iterator loc = locations.begin();
LOG("Using configuration source: \"%s\"", loc->c_str());
for (++loc; loc != locations.end(); ++loc) {
LOG("Using additional configuration source: \"%s\"", loc->c_str());
}
configHandler = new ConfigHandlerImpl(locations, safemode);
//assert(configHandler->GetString("test") == "x y z");
}
void ConfigHandler::Deallocate()
{
SafeDelete(configHandler);
}
/******************************************************************************/