/**
 *    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.
 */
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kControl

#include "mongo/platform/basic.h"

#include "mongo/platform/shared_library.h"

#include <boost/filesystem.hpp>

#include "mongo/util/assert_util.h"
#include "mongo/util/log.h"
#include "mongo/util/mongoutils/str.h"
#include "mongo/util/text.h"

namespace mongo {

    SharedLibrary::~SharedLibrary() {
        if (_handle) {
            if (FreeLibrary(static_cast<HMODULE>(_handle)) == 0) {
                DWORD lasterror = GetLastError();
                LOG(2) << "Load library close failed: " << errnoWithDescription(lasterror);
            }
        }
    }

    StatusWith<std::unique_ptr<SharedLibrary>> SharedLibrary::create(
        const boost::filesystem::path& full_path) {

        LOG(1) << "Loading library: " << toUtf8String(full_path.c_str());

        HMODULE handle = LoadLibraryW(full_path.c_str());
        if (handle == nullptr) {
            return StatusWith<std::unique_ptr<SharedLibrary>>(ErrorCodes::InternalError,
                str::stream() << "Load library failed: " << errnoWithDescription());
        }

        return StatusWith<std::unique_ptr<SharedLibrary>>(
                std::unique_ptr<SharedLibrary>(new SharedLibrary(handle)));
    }

    StatusWith<void*> SharedLibrary::getSymbol(StringData name) {
        // StringData is not assued to be null-terminated
        std::string symbolName = name.toString();

        void* function = GetProcAddress(static_cast<HMODULE>(_handle), symbolName.c_str());

        if (function == nullptr) {
            DWORD gle = GetLastError();
            if (gle != ERROR_PROC_NOT_FOUND) {
                return StatusWith<void*>(ErrorCodes::InternalError,
                    str::stream() << "GetProcAddress failed for symbol: "
                        << errnoWithDescription());
            }
        }

        return StatusWith<void*>(function);
    }

}  // namespace mongo