path: root/src/node.c

#include <stddef.h>

#include "config.h"
#include "node.h"

CMARK_EXPORT cmark_node_type
cmark_node_get_type(cmark_node *node)
{
    return node->type;
}

cmark_node*
cmark_node_next(cmark_node *node)
{
    return node->next;
}

cmark_node*
cmark_node_previous(cmark_node *node)
{
    return node->prev;
}

cmark_node*
cmark_node_parent(cmark_node *node)
{
    return node->parent;
}

cmark_node*
cmark_node_first_child(cmark_node *node)
{
    return node->first_child;
}

cmark_node*
cmark_node_last_child(cmark_node *node)
{
    return node->last_child;
}

static inline bool
S_is_block(cmark_node *node) {
    return node->type >= CMARK_NODE_FIRST_BLOCK
           && node->type <= CMARK_NODE_LAST_BLOCK;
}

static inline bool
S_is_inline(cmark_node *node) {
    return node->type >= CMARK_NODE_FIRST_INLINE
           && node->type <= CMARK_NODE_LAST_INLINE;
}

static bool
S_can_contain(cmark_node *node, cmark_node *child)
{
    if (child->type == CMARK_NODE_DOCUMENT) {
        return false;
    }

    switch (node->type) {
    case CMARK_NODE_DOCUMENT:
    case CMARK_NODE_BQUOTE:
    case CMARK_NODE_LIST_ITEM:
        return S_is_block(child)
               && child->type != CMARK_NODE_LIST_ITEM;

    case CMARK_NODE_LIST:
        return child->type == CMARK_NODE_LIST_ITEM;

    case CMARK_NODE_PARAGRAPH:
    case CMARK_NODE_ATX_HEADER:
    case CMARK_NODE_SETEXT_HEADER:
    case CMARK_NODE_EMPH:
    case CMARK_NODE_STRONG:
    case CMARK_NODE_LINK:
    case CMARK_NODE_IMAGE:
    case CMARK_NODE_LINK_LABEL:
        return S_is_inline(child);

    default:
        break;
    }

    return false;
}

// Unlink a node without adjusting its next, prev, and parent pointers.
static void
S_node_unlink(cmark_node *node)
{
    if (node->prev) {
        node->prev->next = node->next;
    }
    if (node->next) {
        node->next->prev = node->prev;
    }

    // Adjust first_child and last_child of parent.
    cmark_node *parent = node->parent;
    if (parent) {
        if (parent->first_child == node) {
            parent->first_child = node->next;
        }
        if (parent->last_child == node) {
            parent->last_child = node->prev;
        }
    }
}

void
cmark_node_unlink(cmark_node *node) {
    S_node_unlink(node);

    node->next   = NULL;
    node->prev   = NULL;
    node->parent = NULL;
}

int
cmark_node_insert_before(cmark_node *node, cmark_node *sibling)
{
    if (!S_can_contain(node->parent, sibling)) {
        return 0;
    }

    S_node_unlink(sibling);

    cmark_node *old_prev = node->prev;

    // Insert 'sibling' between 'old_prev' and 'node'.
    if (old_prev) {
        old_prev->next = sibling;
    }
    sibling->prev = old_prev;
    sibling->next = node;
    node->prev    = sibling;

    // Set new parent.
    cmark_node *parent = node->parent;
    sibling->parent = parent;

    // Adjust first_child of parent if inserted as first child.
    if (parent && !old_prev) {
        parent->first_child = sibling;
    }

    return 1;
}

int
cmark_node_insert_after(cmark_node *node, cmark_node *sibling)
{
    if (!S_can_contain(node->parent, sibling)) {
        return 0;
    }

    S_node_unlink(sibling);

    cmark_node *old_next = node->next;

    // Insert 'sibling' between 'node' and 'old_next'.
    if (old_next) {
        old_next->prev = sibling;
    }
    sibling->next = old_next;
    sibling->prev = node;
    node->next    = sibling;

    // Set new parent.
    cmark_node *parent = node->parent;
    sibling->parent = parent;

    // Adjust last_child of parent if inserted as last child.
    if (parent && !old_next) {
        parent->last_child = sibling;
    }

    return 1;
}

int
cmark_node_prepend_child(cmark_node *node, cmark_node *child)
{
    if (!S_can_contain(node, child)) {
        return 0;
    }

    S_node_unlink(child);

    cmark_node *old_first_child = node->first_child;

    child->next       = old_first_child;
    child->prev       = NULL;
    child->parent     = node;
    node->first_child = child;

    if (old_first_child) {
        old_first_child->prev = child;
    }
    else {
        // Also set last_child if node previously had no children.
        node->last_child = child;
    }

    return 1;
}

int
cmark_node_append_child(cmark_node *node, cmark_node *child)
{
    if (!S_can_contain(node, child)) {
        return 0;
    }

    S_node_unlink(child);

    cmark_node *old_last_child = node->last_child;

    child->next      = NULL;
    child->prev      = old_last_child;
    child->parent    = node;
    node->last_child = child;

    if (old_last_child) {
        old_last_child->next = child;
    }
    else {
        // Also set first_child if node previously had no children.
        node->first_child = child;
    }

    return 1;
}