APICache.cpp
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#include "hueplusplus/APICache.h"
/**
\file BaseHttpHandler.cpp
Copyright Notice\n
Copyright (C) 2020 Jan Rogall - developer\n
Copyright (C) 2020 Moritz Wirger - developer\n
This file is part of hueplusplus.
hueplusplus is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
hueplusplus is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with hueplusplus. If not, see <http://www.gnu.org/licenses/>.
**/
#include "hueplusplus/HueExceptionMacro.h"
namespace hueplusplus
{
APICache::APICache(std::shared_ptr<APICache> baseCache, const std::string& subEntry)
: base(baseCache),
path(subEntry),
commands(baseCache->commands),
refreshDuration(baseCache->refreshDuration),
lastRefresh(baseCache->lastRefresh)
{}
APICache::APICache(const std::string& path, const HueCommandAPI& commands, std::chrono::steady_clock::duration refresh)
: path(path), commands(commands), refreshDuration(refresh), lastRefresh(std::chrono::steady_clock::duration::zero())
{}
void APICache::refresh()
{
if (base)
{
base->refresh();
}
else
{
value = commands.GETRequest(path, nlohmann::json::object(), CURRENT_FILE_INFO);
lastRefresh = std::chrono::steady_clock::now();
}
}
nlohmann::json& APICache::getValue()
{
if (base)
{
nlohmann::json& baseState = base->getValue();
auto pos = baseState.find(path);
if (pos != baseState.end())
{
return *pos;
}
else
{
throw HueException(CURRENT_FILE_INFO, "Child path not present in base cache");
}
}
else
{
using clock = std::chrono::steady_clock;
// Explicitly check for zero in case refreshDuration is duration::max()
// Negative duration causes overflow check to overflow itself
if (lastRefresh.time_since_epoch().count() == 0 || refreshDuration.count() < 0)
{
// No value set yet
refresh();
}
// Check if nextRefresh would overflow (assumes lastRefresh is not negative, which it should not be).
// If addition would overflow, do not refresh
else if (clock::duration::max() - refreshDuration > lastRefresh.time_since_epoch())
{
clock::time_point nextRefresh = lastRefresh + refreshDuration;
if (clock::now() >= nextRefresh)
{
refresh();
}
}
return value;
}
}
const nlohmann::json& APICache::getValue() const
{
if (base)
{
// Make const reference to not refresh
const APICache& b = *base;
return b.getValue().at(path);
}
else
{
if (lastRefresh.time_since_epoch().count() == 0)
{
// No value has been requested yet
throw HueException(CURRENT_FILE_INFO,
"Tried to call const getValue(), but no value was cached. "
"Call refresh() or non-const getValue() first.");
}
return value;
}
}
std::chrono::steady_clock::duration APICache::getRefreshDuration() const
{
return refreshDuration;
}
HueCommandAPI& APICache::getCommandAPI()
{
return commands;
}
} // namespace hueplusplus