c4::yml::ReferenceResolver Struct Reference

Reusable object to resolve references/aliases in the tree. More...

#include <reference_resolver.hpp>

Public Member Functions
	ReferenceResolver ()=default
void	resolve (Tree *t_)
	Resolve references: for each reference, look for a matching anchor, and copy its contents to the ref node. More...

Detailed Description

Reusable object to resolve references/aliases in the tree.

Definition at line 16 of file reference_resolver.hpp.

Constructor & Destructor Documentation

ReferenceResolver()

c4::yml::ReferenceResolver::ReferenceResolver ( )

default

Member Function Documentation

resolve()

void c4::yml::ReferenceResolver::resolve

(

Tree *

t_

)

Resolve references: for each reference, look for a matching anchor, and copy its contents to the ref node.

This method first does a full traversal of the tree to gather all anchors and references in a separate collection, then it goes through that collection to locate the names, which it does by obeying the YAML standard diktat that "an alias node refers to the most recent node in the serialization having the specified anchor"

So, depending on the number of anchor/alias nodes, this is a potentially expensive operation, with a best-case linear complexity (from the initial traversal).

Definition at line 168 of file reference_resolver.cpp.

{
    _c4dbgp("resolving references...");
 
    reset_(t_);
 
    _c4dbg_tree("unresolved tree", *m_tree);
 
    gather_anchors_and_refs_();
    if(m_refs.empty())
        return;
 
    /* from the specs: "an alias node refers to the most recent
     * node in the serialization having the specified anchor". So
     * we need to start looking upward from ref nodes.
     *
     * @see http://yaml.org/spec/1.2/spec.html#id2765878 */
    _c4dbgp("matching anchors/refs...");
    for(id_type i = 0, e = m_refs.size(); i < e; ++i)
    {
        RefData &C4_RESTRICT refdata = m_refs.top(i);
        if( ! refdata.type.is_ref())
            continue;
        refdata.target = lookup_(&refdata);
    }
    _c4dbgp("matching anchors/refs: finished");
 
    // insert the resolved references
    _c4dbgp("modifying tree...");
    id_type prev_parent_ref = NONE;
    id_type prev_parent_ref_after = NONE;
    for(id_type i = 0, e = m_refs.size(); i < e; ++i)
    {
        RefData const& C4_RESTRICT refdata = m_refs[i];
        _c4dbgpf("instance {}/{}...", i, e);
        if( ! refdata.type.is_ref())
            continue;
        _c4dbgpf("instance {} is reference!", i);
        if(refdata.parent_ref != NONE)
        {
            _c4dbgpf("ref {} has parent: {}", i, refdata.parent_ref);
            _RYML_CB_ASSERT(m_tree->m_callbacks, m_tree->is_seq(refdata.parent_ref));
            const id_type p = m_tree->parent(refdata.parent_ref);
            const id_type after = (prev_parent_ref != refdata.parent_ref) ?
                refdata.parent_ref//prev_sibling(rd.parent_ref_sibling)
                :
                prev_parent_ref_after;
            prev_parent_ref = refdata.parent_ref;
            prev_parent_ref_after = m_tree->duplicate_children_no_rep(refdata.target, p, after);
            m_tree->remove(refdata.node);
        }
        else
        {
            _c4dbgpf("ref {} has no parent", i, refdata.parent_ref);
            if(m_tree->has_key(refdata.node) && m_tree->key(refdata.node) == "<<")
            {
                _c4dbgpf("ref {} is inheriting", i);
                _RYML_CB_ASSERT(m_tree->m_callbacks, m_tree->is_keyval(refdata.node));
                const id_type p = m_tree->parent(refdata.node);
                const id_type after = m_tree->prev_sibling(refdata.node);
                m_tree->duplicate_children_no_rep(refdata.target, p, after);
                m_tree->remove(refdata.node);
            }
            else if(refdata.type.is_key_ref())
            {
                _c4dbgpf("ref {} is key ref", i);
                _RYML_CB_ASSERT(m_tree->m_callbacks, m_tree->is_key_ref(refdata.node));
                _RYML_CB_ASSERT(m_tree->m_callbacks, m_tree->has_key_anchor(refdata.target) || m_tree->has_val_anchor(refdata.target));
                if(m_tree->has_val_anchor(refdata.target) && m_tree->val_anchor(refdata.target) == m_tree->key_ref(refdata.node))
                {
                    _RYML_CB_CHECK(m_tree->m_callbacks, !m_tree->is_container(refdata.target));
                    _RYML_CB_CHECK(m_tree->m_callbacks, m_tree->has_val(refdata.target));
                    const type_bits existing_style_flags = VAL_STYLE & m_tree->_p(refdata.target)->m_type.type;
                    static_assert((VAL_STYLE >> 1u) == (KEY_STYLE), "bad flags");
                    m_tree->_p(refdata.node)->m_key.scalar = m_tree->val(refdata.target);
                    m_tree->_add_flags(refdata.node, KEY | (existing_style_flags >> 1u));
                }
                else
                {
                    _RYML_CB_CHECK(m_tree->m_callbacks, m_tree->key_anchor(refdata.target) == m_tree->key_ref(refdata.node));
                    m_tree->_p(refdata.node)->m_key.scalar = m_tree->key(refdata.target);
                    // keys cannot be containers, so don't inherit container flags
                    const type_bits existing_style_flags = KEY_STYLE & m_tree->_p(refdata.target)->m_type.type;
                    m_tree->_add_flags(refdata.node, KEY | existing_style_flags);
                }
            }
            else // val ref
            {
                _c4dbgpf("ref {} is val ref", i);
                _RYML_CB_ASSERT(m_tree->m_callbacks, refdata.type.is_val_ref());
                if(m_tree->has_key_anchor(refdata.target) && m_tree->key_anchor(refdata.target) == m_tree->val_ref(refdata.node))
                {
                    _RYML_CB_CHECK(m_tree->m_callbacks, !m_tree->is_container(refdata.target));
                    _RYML_CB_CHECK(m_tree->m_callbacks, m_tree->has_val(refdata.target));
                    // keys cannot be containers, so don't inherit container flags
                    const type_bits existing_style_flags = (KEY_STYLE) & m_tree->_p(refdata.target)->m_type.type;
                    static_assert((KEY_STYLE << 1u) == (VAL_STYLE), "bad flags");
                    m_tree->_p(refdata.node)->m_val.scalar = m_tree->key(refdata.target);
                    m_tree->_add_flags(refdata.node, VAL | (existing_style_flags << 1u));
                }
                else
                {
                    m_tree->duplicate_contents(refdata.target, refdata.node);
                }
            }
        }
    }
    _c4dbgp("modifying tree: finished");
 
    // clear anchors and refs
    _c4dbgp("clearing anchors/refs");
    for(auto const& C4_RESTRICT ar : m_refs)
    {
        m_tree->rem_anchor_ref(ar.node);
        if(ar.parent_ref != NONE)
            if(m_tree->type(ar.parent_ref) != NOTYPE)
                m_tree->remove(ar.parent_ref);
    }
    _c4dbgp("clearing anchors/refs: finished");
 
    _c4dbg_tree("resolved tree", *m_tree);
 
    m_tree = nullptr;
    _c4dbgp("resolving references: finished");
}

References _c4dbg_tree, c4::yml::KEY, c4::yml::KEY_STYLE, c4::yml::NONE, c4::yml::NOTYPE, c4::yml::VAL, and c4::yml::VAL_STYLE.

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The documentation for this struct was generated from the following files:

• /home/docs/checkouts/readthedocs.org/user_builds/rapidyaml/checkouts/v0.7.2/src/c4/yml/reference_resolver.hpp
• /home/docs/checkouts/readthedocs.org/user_builds/rapidyaml/checkouts/v0.7.2/src/c4/yml/reference_resolver.cpp