| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef __STOUT_WINDOWS_DYNAMICLIBRARY_HPP__ |
| #define __STOUT_WINDOWS_DYNAMICLIBRARY_HPP__ |
| |
| #include <string> |
| |
| #include <stout/error.hpp> |
| #include <stout/nothing.hpp> |
| #include <stout/option.hpp> |
| #include <stout/stringify.hpp> |
| #include <stout/try.hpp> |
| |
| /** |
| * DynamicLibrary is a very simple wrapper around the programming interface |
| * to the dynamic linking loader. |
| */ |
| class DynamicLibrary |
| { |
| public: |
| DynamicLibrary() : handle_(nullptr) { } |
| |
| // Since this class manages a naked handle it cannot be copy- or |
| // move-constructed. |
| // TODO(bbannier): Allow for move-construction. |
| DynamicLibrary(const DynamicLibrary&) = delete; |
| DynamicLibrary(DynamicLibrary&&) = delete; |
| |
| virtual ~DynamicLibrary() |
| { |
| if (handle_ != nullptr) { |
| close(); |
| } |
| } |
| |
| Try<Nothing> open(const std::string& path) |
| { |
| // Check if we've already opened a library. |
| if (handle_ != nullptr) { |
| return Error("Library already opened"); |
| } |
| |
| handle_ = ::LoadLibraryW(wide_stringify(path).data()); |
| |
| if (handle_ == nullptr) { |
| return WindowsError("Could not load library '" + path + "'"); |
| } |
| |
| path_ = path; |
| |
| return Nothing(); |
| } |
| |
| Try<Nothing> close() |
| { |
| if (handle_ == nullptr) { |
| return Error("Could not close library; handle was already `nullptr`"); |
| } |
| |
| if (!::FreeLibrary(handle_)) { |
| return WindowsError( |
| "Could not close library '" + (path_.isSome() ? path_.get() : "")); |
| } |
| |
| handle_ = nullptr; |
| path_ = None(); |
| |
| return Nothing(); |
| } |
| |
| Try<void*> loadSymbol(const std::string& name) |
| { |
| if (handle_ == nullptr) { |
| return Error( |
| "Could not get symbol '" + name + "'; library handle was `nullptr`"); |
| } |
| |
| void* symbol = ::GetProcAddress(handle_, name.c_str()); |
| |
| if (symbol == nullptr) { |
| return WindowsError( |
| "Error looking up symbol '" + name + "' in '" + |
| (path_.isSome() ? path_.get() : "")); |
| } |
| |
| return symbol; |
| } |
| |
| private: |
| HMODULE handle_; |
| Option<std::string> path_; |
| }; |
| |
| #endif // __STOUT_WINDOWS_DYNAMICLIBRARY_HPP__ |