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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <boost/filesystem.hpp>
#include <memory>
#include "mongo/base/status_with.h"
namespace mongo {
/**
* Loads shared library or DLL at runtime
* Provides functionality to resolve symols and functions at runtime.
* Note: shared library is released by destructor
*/
class SharedLibrary {
public:
/**
* Releases reference to shared library on destruction.
*
* May unload the shared library.
* May invalidate all symbol pointers, depends on OS implementation.
*/
~SharedLibrary();
/*
* Loads the shared library
*
* Returns a handle to a SharedLibrary on success otherwise StatusWith contains the
* appropriate error.
*/
static StatusWith<std::unique_ptr<SharedLibrary>> create(
const boost::filesystem::path& full_path);
/**
* Retrieves the public symbol of a shared library specified in the name parameter.
*
* Returns a pointer to the symbol if it exists with Status::OK,
* returns NULL if the symbol does not exist with Status::OK,
* otherwise returns an error if the underlying OS infrastructure returns an error.
*/
StatusWith<void*> getSymbol(StringData name);
/**
* A generic function version of getSymbol, see notes in getSymbol for more information
* Callers should use getFunctionAs.
*/
StatusWith<void (*)()> getFunction(StringData name);
/**
* A type-safe version of getFunction, see notes in getSymbol for more information
*/
template<typename FuncT>
StatusWith<FuncT> getFunctionAs(StringData name) {
StatusWith<void (*) ()> s = getFunction(name);
if (!s.isOK()) {
return StatusWith<FuncT>(s.getStatus());
}
return StatusWith<FuncT>(reinterpret_cast<FuncT>(s.getValue()));
}
private:
SharedLibrary(void* handle);
private:
void* const _handle;
};
} // namespace mongo
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