Method push

libs/command/kundo2stack.cpp:722–892

*/

void KUndo2QStack::push(KUndo2Command *cmd)
{
    cmd->redoMergedCommands();

    if (cmd->endTime().isNull()) {
        cmd->setEndTime();
    }

    bool macro = !m_macro_stack.isEmpty();

    KUndo2Command *cur = 0;
    if (macro) {
        KUndo2Command *macro_cmd = m_macro_stack.last();
        if (!macro_cmd->d->child_list.isEmpty())
            cur = macro_cmd->d->child_list.last();
    } else {
        if (m_index > 0)
            cur = m_command_list.at(m_index - 1);
        while (m_index < m_command_list.size())
            delete m_command_list.takeLast();
        if (m_clean_index > m_index)
            m_clean_index = -1; // we've deleted the clean state
    }

    bool try_merge = cur != 0
                     && cur->id() != -1
                     && cur->id() == cmd->id()
                     && (macro || m_index != m_clean_index);

    /**
     * Here we are going to try to merge several commands together using the
     * QVector field in the commands using 3 parameters.
     *
     * N : Number of commands that should remain individual at the top of the
     *     stack.
     *
     * T1 : Timeout for the commands to be outdated and merged
     *
     * T2 : Time separation between two commands to be considered as belonging
     *      to the same group
     *
     */

    if (!macro && m_command_list.size() > 1 && cmd->timedId() != -1 && m_useCumulativeUndoRedo) {
        KUndo2Command* lastcmd = m_command_list.last();

        auto tryMergeBack =
            [this] (auto revIt, bool *isMerged) {
                /// we have a guarantee that std::next(revIt) exists,
                /// so we can safely iterate back in the forward order
                auto dst = std::prev(revIt.base());
                auto src = std::prev(dst);

                if ((*dst)->timedId() != -1 &&
                    (*dst)->timedId() == (*src)->timedId() &&
                    (*src)->time().msecsTo((*dst)->endTime()) <= m_cumulativeUndoData.maxGroupDuration &&
                    (*src)->endTime().msecsTo((*dst)->time()) <= m_cumulativeUndoData.maxGroupSeparation &&
                    (*dst)->timedMergeWith(*src)) {