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wlan-cloud-lib-cppkafka/include/cppkafka/detail/callback_invoker.h
2018-08-30 11:28:12 -07:00

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4.3 KiB
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/*
* Copyright (c) 2017, Matias Fontanini
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef CPPKAFKA_CALLBACK_INVOKER_H
#define CPPKAFKA_CALLBACK_INVOKER_H
#include <sstream>
#include <assert.h>
#include "../logging.h"
#include "../kafka_handle_base.h"
namespace cppkafka {
// Error values
template <typename T>
T error_value() { return T{}; }
template<> inline
void error_value<void>() {};
template<> inline
bool error_value<bool>() { return false; }
template<> inline
int error_value<int>() { return -1; }
/**
* \brief Wraps an std::function object and runs it while preventing all exceptions from escaping
* \tparam Func An std::function object
*/
template <typename Func>
class CallbackInvoker
{
public:
using RetType = typename Func::result_type;
using LogCallback = std::function<void(KafkaHandleBase& handle,
int level,
const std::string& facility,
const std::string& message)>;
CallbackInvoker(const char* callback_name,
const Func& callback,
KafkaHandleBase* handle)
: callback_name_(callback_name),
callback_(callback),
handle_(handle) {
}
explicit operator bool() const {
return (bool)callback_;
}
template <typename ...Args>
RetType operator()(Args&&... args) const {
static const char* library_name = "cppkafka";
std::ostringstream error_msg;
try {
if (callback_) {
return callback_(std::forward<Args>(args)...);
}
return error_value<RetType>();
}
catch (const std::exception& ex) {
if (handle_) {
error_msg << "Caught exception in " << callback_name_ << " callback: " << ex.what();
}
}
catch (...) {
if (handle_) {
error_msg << "Caught unknown exception in " << callback_name_ << " callback";
}
}
// Log error
if (handle_) {
if (handle_->get_configuration().get_log_callback()) {
try {
// Log it
handle_->get_configuration().get_log_callback()(*handle_,
static_cast<int>(LogLevel::LogErr),
library_name,
error_msg.str());
}
catch (...) {} // sink everything
}
else {
rd_kafka_log_print(handle_->get_handle(),
static_cast<int>(LogLevel::LogErr),
library_name,
error_msg.str().c_str());
}
}
return error_value<RetType>();
}
private:
const char* callback_name_;
const Func& callback_;
KafkaHandleBase* handle_;
};
}
#endif