C++ Iter::search_below_dst方法代码示例

// Call this function when searching below a dst_type node.  This function searches
// for a path to (static_ptr, static_type) and for paths to one or more dst_type nodes.
// If it finds a static_type node, there is no need to further search base classes
// above.
// If it finds a dst_type node it should search base classes using search_above_dst
// to find out if this dst_type points to (static_ptr, static_type) or not.
// Either way, the dst_type is recorded as one of two "flavors":  one that does
// or does not point to (static_ptr, static_type).
// If this is neither a static_type nor a dst_type node, continue searching
// base classes above.
// All the hoopla surrounding the search code is doing nothing but looking for
// excuses to stop the search prematurely (break out of the for-loop).  That is,
// the algorithm below is simply an optimization of this:
// void
// __vmi_class_type_info::search_below_dst(__dynamic_cast_info* info,
//                                         const void* current_ptr,
//                                         int path_below) const
// {
//     typedef const __base_class_type_info* Iter;
//     if (this == info->static_type)
//         process_static_type_below_dst(info, current_ptr, path_below);
//     else if (this == info->dst_type)
//     {
//         // Record the most public access path that got us here
//         if (info->path_dynamic_ptr_to_dst_ptr != public_path)
//             info->path_dynamic_ptr_to_dst_ptr = path_below;
//         bool does_dst_type_point_to_our_static_type = false;
//         for (Iter p = __base_info, e= __base_info + __base_count; p < e; ++p)
//         {
//             p->search_above_dst(info, current_ptr, current_ptr, public_path);
//             if (info->found_our_static_ptr)
//                 does_dst_type_point_to_our_static_type = true;
//             // break out early here if you can detect it doesn't matter if you do
//         }
//         if (!does_dst_type_point_to_our_static_type)
//         {
//             // We found a dst_type that doesn't point to (static_ptr, static_type)
//             // So record the address of this dst_ptr and increment the
//             // count of the number of such dst_types found in the tree.
//             info->dst_ptr_not_leading_to_static_ptr = current_ptr;
//             info->number_to_dst_ptr += 1;
//         }
//     }
//     else
//     {
//         // This is not a static_type and not a dst_type.
//         for (Iter p = __base_info, e = __base_info + __base_count; p < e; ++p)
//         {
//             p->search_below_dst(info, current_ptr, public_path);
//             // break out early here if you can detect it doesn't matter if you do
//         }
//     }
// }
void
__vmi_class_type_info::search_below_dst(__dynamic_cast_info* info,
                                        const void* current_ptr,
                                        int path_below,
                                        bool use_strcmp) const
{
    typedef const __base_class_type_info* Iter;
    if (is_equal(this, info->static_type, use_strcmp))
        process_static_type_below_dst(info, current_ptr, path_below);
    else if (is_equal(this, info->dst_type, use_strcmp))
    {
        // We've been here before if we've recorded current_ptr in one of these
        //   two places:
        if (current_ptr == info->dst_ptr_leading_to_static_ptr ||
            current_ptr == info->dst_ptr_not_leading_to_static_ptr)
        {
            // We've seen this node before, and therefore have already searched
            // its base classes above.
            //  Update path to here that is "most public".
            if (path_below == public_path)
                info->path_dynamic_ptr_to_dst_ptr = public_path;
        }
        else  // We have haven't been here before
        {
            // Record the access path that got us here
            //   If there is more than one dst_type this path doesn't matter.
            info->path_dynamic_ptr_to_dst_ptr = path_below;
            // Only search above here if dst_type derives from static_type, or
            //    if it is unknown if dst_type derives from static_type.
            if (info->is_dst_type_derived_from_static_type != no)
            {
                // Set up flags to record results from all base classes
                bool is_dst_type_derived_from_static_type = false;
                bool does_dst_type_point_to_our_static_type = false;
                // We've found a dst_type with a potentially public path to here.
                // We have to assume the path is public because it may become
                //   public later (if we get back to here with a public path).
                // We can stop looking above if:
                //    1.  We've found a public path to (static_ptr, static_type).
                //    2.  We've found an ambiguous cast from (static_ptr, static_type) to a dst_type.
                //        This is detected at the (static_ptr, static_type).
                //    3.  We can prove that there is no public path to (static_ptr, static_type)
                //        above here.
                const Iter e = __base_info + __base_count;
                for (Iter p = __base_info; p < e; ++p)
                {
                    // Zero out found flags
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