README.md

undo-cxx

undo-cxx C++17/20 library provides a undo/redo subsystem (linear or restricted non-linear).

Newest

• v0.3.2, security patch for github workflow; fix arch detections in dummy project - affect generating undo-cxx_config.hh
• v0.3.1, added newest_item() for #1
• v0.3.0, build passed for c++20
• v0.2.5, upgrade undo-log.hh, undo-util.hh, undo-zcore.hh, and cxx-macros.cmake
• v0.2.3, upgrade cmake scripts
• v0.2.2, fixes around the project files
• v0.2.1, first implementation of Undoable/Redoable

Features

• Highly configurable/customizable
• Undo/Redo subsystem
  • restricted non-linear undo (batch undo+erase+redo)
  • todo: full-functional non-linear
  • limitless undo/redo levels, or limited with max_size(n)
• Bundled with Command subsystem
  • undoable/redoable
  • Composite command (undo_cxx::composite_cmd_t<>): composite multi-commands as one (groupable)
  • Composite memento (undo_cxx::state_t<>) for composite-command

Examples

The following code is a part of a word-processor:

#include <undo_cxx.hh>

namespace dp { namespace undo { namespace test {

    template<typename State>
    class FontStyleCmd : public undo_cxx::cmd_t<State> {
    public:
        ~FontStyleCmd() {}
        FontStyleCmd() {}
        FontStyleCmd(std::string const &default_state_info)
            : _info(default_state_info) {}
        UNDO_CXX_DEFINE_DEFAULT_CMD_TYPES(FontStyleCmd, undo_cxx::cmd_t);

    protected:
        void do_execute(CmdSP &sender, ContextT &) override {
            UNUSED(sender);
            // ... do sth to add/remove font style to/from
            // current selection in current editor ...
            std::cout << "<<" << _info << ">>" << '\n';
        }
        MementoPtr save_state_impl(CmdSP &sender, ContextT &) override {
            return std::make_unique<Memento>(sender, _info);
        }
        void undo_impl(CmdSP &sender, ContextT &, Memento &memento) override {
            memento = _info;
            memento.command(sender);
        }
        void redo_impl(CmdSP &sender, ContextT &, Memento &memento) override {
            memento = _info;
            memento.command(sender);
        }

    private:
        std::string _info{"make italic"};
    };

    template<typename State>
    class UndoCmd : public undo_cxx::base_undo_cmd_t<State> {
    public:
        ~UndoCmd() {}
        using undo_cxx::base_undo_cmd_t<State>::base_undo_cmd_t;
        UndoCmd(std::string const &default_state_info)
            : _info(default_state_info) {}
        UNDO_CXX_DEFINE_DEFAULT_CMD_TYPES(UndoCmd, undo_cxx::base_undo_cmd_t);

    protected:
        void do_execute(CmdSP &sender, ContextT &ctx) override {
            std::cout << "<<" << _info << ">>" << '\n';
            Base::do_execute(sender, ctx);
        }
        MementoPtr save_state_impl(CmdSP &sender, ContextT &) override {
            return std::make_unique<Memento>(sender, _info);
        }
        void undo_impl(CmdSP &sender, ContextT &, Memento &memento) override {
            memento = "do 'undo'";
            // auto sp = typename Memento::CmdSP(this);
            memento.command(sender);
        }
        void redo_impl(CmdSP &sender, ContextT &, Memento &memento) override {
            memento = "do 'un-undo' again";
            memento.command(sender);
        }

    private:
        std::string _info{"do 'undo'"};
    };

    template<typename State>
    class RedoCmd : public undo_cxx::base_redo_cmd_t<State> {
    public:
        ~RedoCmd() {}
        using undo_cxx::base_redo_cmd_t<State>::base_redo_cmd_t;
        RedoCmd(std::string const &default_state_info)
            : _info(default_state_info) {}
        UNDO_CXX_DEFINE_DEFAULT_CMD_TYPES(RedoCmd, undo_cxx::base_redo_cmd_t);

    protected:
        void do_execute(CmdSP &sender, ContextT &ctx) override {
            std::cout << "<<" << _info << ">>" << '\n';
            Base::do_execute(sender, ctx);
        }
        MementoPtr save_state_impl(CmdSP &sender, ContextT &) override {
            return std::make_unique<Memento>(sender, _info);
        }
        void undo_impl(CmdSP &sender, ContextT &, Memento &memento) override {
            memento = "do 'redo'";
            memento.command(sender);
        }
        void redo_impl(CmdSP &sender, ContextT &, Memento &memento) override {
            memento = "do 'un-redo' again";
            memento.command(sender);
        }

    private:
        std::string _info{"do 'redo'"};
    };

}}} // namespace dp::undo::test

void test_undo_sys() {
    using namespace dp::undo::test;
    using namespace dp::undo::bugs;

    using State = std::string;
    using M = undo_cxx::undoable_cmd_system_t<State>;
    using UndoCmdT = UndoCmd<State>;
    using RedoCmdT = RedoCmd<State>;
    using FontStyleCmdT = FontStyleCmd<State>;

    M undoable_cmd_system;

    // do some stuffs

    undoable_cmd_system.invoke<FontStyleCmdT>("italic state1");
    undoable_cmd_system.invoke<FontStyleCmdT>("italic-bold state2");
    undoable_cmd_system.invoke<FontStyleCmdT>("underline state3");
    undoable_cmd_system.invoke<FontStyleCmdT>("italic state4");

    // and try to undo or redo

    undoable_cmd_system.invoke<UndoCmdT>("undo 1");
    undoable_cmd_system.invoke<UndoCmdT>("undo 2");
    undoable_cmd_system.invoke<RedoCmdT>("redo 1");
    undoable_cmd_system.invoke<UndoCmdT>("undo 3");
    undoable_cmd_system.invoke<UndoCmdT>("undo 4");
}

int main() {
    test_undo_sys();
    return 0;
}

Build Options

Build with CMake

1. gcc 10+: passed
2. clang 12+: passed
3. msvc build tool 16.7.2, 16.8.5 (VS2019 or Build Tool) passed

ninja is optional for faster building.

# configure
cmake -S . -B build/ -G Ninja
# build
cmake --build build/
# install
cmake --install build/
# Or:cmake --build build/ --target install
#
# Sometimes sudo it:
#   sudo cmake --build build/ --target install
# Or manually:
#   cmake --install build/ --prefix ./install --strip
#   sudo cp -R ./install/include/* /usr/local/include/
#   sudo cp -R ./install/lib/cmake/undo_cxx /usr/local/lib/cmake/

Other CMake Options

1. UNDO_CXX_BUILD_TESTS_EXAMPLES=OFF
2. UNDO_CXX_BUILD_DOCS=OFF
3. ...

Thanks to JODL

Thanks to JetBrains for donating product licenses to help develop undo-cxx

LICENSE

Apache 2.0