path: root/src/html.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include "config.h"
#include "cmark.h"
#include "node.h"
#include "buffer.h"
#include "houdini.h"

// Functions to convert cmark_nodes to HTML strings.

static void escape_html(strbuf *dest, const unsigned char *source, int length)
{
    if (length < 0)
        length = strlen((char *)source);

    houdini_escape_html0(dest, source, (size_t)length, 0);
}

static void escape_href(strbuf *dest, const unsigned char *source, int length)
{
    if (length < 0)
        length = strlen((char *)source);

    houdini_escape_href(dest, source, (size_t)length);
}

static inline void cr(strbuf *html)
{
    if (html->size && html->ptr[html->size - 1] != '\n')
        strbuf_putc(html, '\n');
}

struct render_state {
    strbuf* html;
    cmark_node *plain;
};

static int
S_render_node(cmark_node *node, cmark_event_type ev_type, void *vstate)
{
    struct render_state *state = vstate;
    cmark_node *parent;
    cmark_node *grandparent;
    strbuf *html = state->html;
    char start_header[] = "<h0>";
    char end_header[] = "</h0>";
    strbuf *info;
    bool tight;

    bool entering = (ev_type == CMARK_EVENT_ENTER);

    if (state->plain == node) { // back at original node
        state->plain = NULL;
    }

    if (state->plain != NULL) {
        switch(node->type) {
        case CMARK_NODE_TEXT:
        case CMARK_NODE_CODE:
        case CMARK_NODE_INLINE_HTML:
            escape_html(html, node->as.literal.data,
                    node->as.literal.len);
            break;

        case CMARK_NODE_LINEBREAK:
        case CMARK_NODE_SOFTBREAK:
            strbuf_putc(html, ' ');
            break;

        default:
            break;
        }
        return 1;
    }

    switch (node->type) {
    case CMARK_NODE_DOCUMENT:
        break;

    case CMARK_NODE_BLOCK_QUOTE:
        if (entering) {
            cr(html);
            strbuf_puts(html, "<blockquote>\n");
        } else {
            cr(html);
            strbuf_puts(html, "</blockquote>\n");
        }
        break;

    case CMARK_NODE_LIST: {
        cmark_list_type list_type = node->as.list.list_type;
        int start = node->as.list.start;

        if (entering) {
            cr(html);
            if (list_type == CMARK_BULLET_LIST) {
                strbuf_puts(html, "<ul>\n");
            }
            else if (start == 1) {
                strbuf_puts(html, "<ol>\n");
            }
            else {
                strbuf_printf(html, "<ol start=\"%d\">\n",
                          start);
            }
        } else {
            strbuf_puts(html,
                    list_type == CMARK_BULLET_LIST ?
                    "</ul>\n" : "</ol>\n");
        }
        break;
    }

    case CMARK_NODE_LIST_ITEM:
        if (entering) {
            cr(html);
            strbuf_puts(html, "<li>");
        } else {
            strbuf_puts(html, "</li>\n");
        }
        break;

    case CMARK_NODE_HEADER:
        if (entering) {
            cr(html);
            start_header[2] = '0' + node->as.header.level;
            strbuf_puts(html, start_header);
        } else {
            end_header[3] = '0' + node->as.header.level;
            strbuf_puts(html, end_header);
            strbuf_putc(html, '\n');
        }
        break;

    case CMARK_NODE_CODE_BLOCK:
        info = &node->as.code.info;
        cr(html);

        if (&node->as.code.fence_length == 0
            || strbuf_len(info) == 0) {
            strbuf_puts(html, "<pre><code>");
        }
        else {
            int first_tag = strbuf_strchr(info, ' ', 0);
            if (first_tag < 0)
                first_tag = strbuf_len(info);

            strbuf_puts(html, "<pre><code class=\"language-");
            escape_html(html, info->ptr, first_tag);
            strbuf_puts(html, "\">");
        }

        escape_html(html, node->as.literal.data, node->as.literal.len);
        strbuf_puts(html, "</code></pre>\n");
        break;

    case CMARK_NODE_HTML:
        cr(html);
        strbuf_put(html, node->as.literal.data, node->as.literal.len);
        break;

    case CMARK_NODE_HRULE:
        cr(html);
        strbuf_puts(html, "<hr />\n");
        break;

    case CMARK_NODE_PARAGRAPH:
        parent = cmark_node_parent(node);
        grandparent = cmark_node_parent(parent);
        if (grandparent != NULL &&
            grandparent->type == CMARK_NODE_LIST) {
            tight = grandparent->as.list.tight;
        } else {
            tight = false;
        }
        if (!tight) {
            if (entering) {
                cr(html);
                strbuf_puts(html, "<p>");
            } else {
                strbuf_puts(html, "</p>\n");
            }
        }
        break;

    case CMARK_NODE_TEXT:
        escape_html(html, node->as.literal.data,
                node->as.literal.len);
        break;

    case CMARK_NODE_LINEBREAK:
        strbuf_puts(html, "<br />\n");
        break;

    case CMARK_NODE_SOFTBREAK:
        strbuf_putc(html, '\n');
        break;

    case CMARK_NODE_CODE:
        strbuf_puts(html, "<code>");
        escape_html(html, node->as.literal.data, node->as.literal.len);
        strbuf_puts(html, "</code>");
        break;

    case CMARK_NODE_INLINE_HTML:
        strbuf_put(html, node->as.literal.data, node->as.literal.len);
        break;

    case CMARK_NODE_STRONG:
        if (entering) {
            strbuf_puts(html, "<strong>");
        } else {
            strbuf_puts(html, "</strong>");
        }
        break;

    case CMARK_NODE_EMPH:
        if (entering) {
            strbuf_puts(html, "<em>");
        } else {
            strbuf_puts(html, "</em>");
        }
        break;

    case CMARK_NODE_LINK:
        if (entering) {
            strbuf_puts(html, "<a href=\"");
            if (node->as.link.url)
                escape_href(html, node->as.link.url, -1);

            if (node->as.link.title) {
                strbuf_puts(html, "\" title=\"");
                escape_html(html, node->as.link.title, -1);
            }

            strbuf_puts(html, "\">");
        } else {
            strbuf_puts(html, "</a>");
        }
        break;

    case CMARK_NODE_IMAGE:
        if (entering) {
            strbuf_puts(html, "<img src=\"");
            if (node->as.link.url)
                escape_href(html, node->as.link.url, -1);

            strbuf_puts(html, "\" alt=\"");
            state->plain = node;
        } else {
            if (node->as.link.title) {
                strbuf_puts(html, "\" title=\"");
                escape_html(html, node->as.link.title, -1);
            }

            strbuf_puts(html, "\" />");
        }
        break;

    default:
        assert(false);
        break;
    }

    // strbuf_putc(html, 'x');
    return 1;
}

char *cmark_render_html(cmark_node *root)
{
    char *result;
    strbuf html = GH_BUF_INIT;
    cmark_event_type ev_type;
    cmark_node *cur;
    struct render_state state = { &html, NULL };
    cmark_iter *iter = cmark_iter_new(root);

    while ((ev_type = cmark_iter_next(iter)) != CMARK_EVENT_DONE) {
        cur = cmark_iter_get_node(iter);
        S_render_node(cur, ev_type, &state);
    }
    result = (char *)strbuf_detach(&html);

    cmark_iter_free(iter);
    strbuf_free(&html);
    return result;
}