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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <ctype.h>
#include "config.h"
#include "cmark.h"
#include "node.h"
#include "buffer.h"
#include "utf8.h"
// Functions to convert cmark_nodes to commonmark strings.
struct render_state {
int options;
cmark_strbuf* buffer;
cmark_strbuf* prefix;
int column;
int width;
int need_cr;
int last_breakable;
bool begin_line;
bool no_wrap;
bool in_tight_list_item;
};
static inline void cr(struct render_state *state)
{
if (state->need_cr < 1) {
state->need_cr = 1;
}
}
static inline void blankline(struct render_state *state)
{
if (state->need_cr < 2) {
state->need_cr = 2;
}
}
static inline void double_blankline(struct render_state *state)
{
if (state->need_cr < 3) {
state->need_cr = 3;
}
}
typedef enum {
LITERAL,
NORMAL,
TITLE,
URL,
BRACED_URL
} escaping;
static inline bool
needs_escaping(escaping escape,
int32_t c,
unsigned char next_c,
struct render_state *state)
{
if (escape == NORMAL) {
return (c == '*' || c == '_' || c == '[' || c == ']' ||
c == '<' || c == '>' || c == '\\' ||
(c == '&' && isalpha(next_c)) ||
(c == '!' && next_c == '[') ||
(state->begin_line &&
(c == '-' || c == '+' || c == '#' || c == '=')) ||
(c == '#' && (isspace(next_c) || next_c == '\0')) ||
((c == '.' || c == ')') &&
isdigit(state->buffer->ptr[state->buffer->size - 1])));
} else if (escape == TITLE) {
return (c == '`' || c == '<' || c == '>' || c == '"' ||
c == '\\');
} else if (escape == URL) {
return (c == '`' || c == '<' || c == '>' || isspace(c) ||
c == '\\' || c == ')' || c == '(');
} else if (escape == BRACED_URL) {
return (c == '`' || c == '<' || c == '>' || c == '\\');
} else {
return false;
}
}
static inline void out(struct render_state *state,
cmark_chunk str,
bool wrap,
escaping escape)
{
unsigned char* source = str.data;
int length = str.len;
unsigned char nextc;
int32_t c;
int i = 0;
int len;
cmark_chunk remainder = cmark_chunk_literal("");
int k = state->buffer->size - 1;
wrap = wrap && !state->no_wrap;
if (state->in_tight_list_item && state->need_cr > 1) {
state->need_cr = 1;
}
while (state->need_cr) {
if (k < 0 || state->buffer->ptr[k] == '\n') {
k -= 1;
} else {
cmark_strbuf_putc(state->buffer, '\n');
if (state->need_cr > 1) {
cmark_strbuf_put(state->buffer, state->prefix->ptr,
state->prefix->size);
}
}
state->column = 0;
state->begin_line = true;
state->need_cr -= 1;
}
while (i < length) {
if (state->begin_line) {
cmark_strbuf_put(state->buffer, state->prefix->ptr,
state->prefix->size);
// note: this assumes prefix is ascii:
state->column = state->prefix->size;
}
len = utf8proc_iterate(source + i, length - i, &c);
nextc = source[i + len];
if (c == 32 && wrap) {
if (!state->begin_line) {
cmark_strbuf_putc(state->buffer, ' ');
state->column += 1;
state->begin_line = false;
state->last_breakable = state->buffer->size -
1;
// skip following spaces
while (source[i + 1] == ' ') {
i++;
}
}
} else if (c == 10) {
cmark_strbuf_putc(state->buffer, '\n');
state->column = 0;
state->begin_line = true;
state->last_breakable = 0;
} else if (needs_escaping(escape, c, nextc, state)) {
if (isspace(c)) {
// use percent encoding for spaces
cmark_strbuf_printf(state->buffer, "%%%2x", c);
state->column += 3;
} else {
cmark_strbuf_putc(state->buffer, '\\');
utf8proc_encode_char(c, state->buffer);
state->column += 2;
}
state->begin_line = false;
} else {
utf8proc_encode_char(c, state->buffer);
state->column += 1;
state->begin_line = false;
}
// If adding the character went beyond width, look for an
// earlier place where the line could be broken:
if (state->width > 0 &&
state->column > state->width &&
!state->begin_line &&
state->last_breakable > 0) {
// copy from last_breakable to remainder
cmark_chunk_set_cstr(&remainder, (char *) state->buffer->ptr + state->last_breakable + 1);
// truncate at last_breakable
cmark_strbuf_truncate(state->buffer, state->last_breakable);
// add newline, prefix, and remainder
cmark_strbuf_putc(state->buffer, '\n');
cmark_strbuf_put(state->buffer, state->prefix->ptr,
state->prefix->size);
cmark_strbuf_put(state->buffer, remainder.data, remainder.len);
state->column = state->prefix->size + remainder.len;
cmark_chunk_free(&remainder);
state->last_breakable = 0;
state->begin_line = false;
}
i += len;
}
}
static void lit(struct render_state *state, char *s, bool wrap)
{
cmark_chunk str = cmark_chunk_literal(s);
out(state, str, wrap, LITERAL);
}
static int
longest_backtick_sequence(cmark_chunk *code)
{
int longest = 0;
int current = 0;
int i = 0;
while (i <= code->len) {
if (code->data[i] == '`') {
current++;
} else {
if (current > longest) {
longest = current;
}
current = 0;
}
i++;
}
return longest;
}
static int
shortest_unused_backtick_sequence(cmark_chunk *code)
{
int32_t used = 1;
int current = 0;
int i = 0;
while (i <= code->len) {
if (code->data[i] == '`') {
current++;
} else {
if (current) {
used |= (1 << current);
}
current = 0;
}
i++;
}
// return number of first bit that is 0:
i = 0;
while (used & 1) {
used = used >> 1;
i++;
}
return i;
}
static int
S_render_node(cmark_node *node, cmark_event_type ev_type,
struct render_state *state)
{
cmark_node *tmp;
cmark_chunk *code;
int list_number;
cmark_delim_type list_delim;
int numticks;
int i;
bool entering = (ev_type == CMARK_EVENT_ENTER);
const char *info;
const char *title;
char listmarker[64];
char *emph_delim;
int marker_width;
state->in_tight_list_item =
node->type == CMARK_NODE_ITEM &&
cmark_node_get_list_tight(node->parent);
switch (node->type) {
case CMARK_NODE_DOCUMENT:
if (!entering) {
cmark_strbuf_putc(state->buffer, '\n');
}
break;
case CMARK_NODE_BLOCK_QUOTE:
if (entering) {
lit(state, "> ", false);
cmark_strbuf_puts(state->prefix, "> ");
} else {
cmark_strbuf_truncate(state->prefix,
state->prefix->size - 2);
blankline(state);
}
break;
case CMARK_NODE_LIST:
if (!entering && node->next &&
(node->next->type == CMARK_NODE_CODE_BLOCK ||
node->next->type == CMARK_NODE_LIST)) {
// two blank lines after list before code block or list
double_blankline(state);
}
break;
case CMARK_NODE_ITEM:
if (cmark_node_get_list_type(node->parent) ==
CMARK_BULLET_LIST) {
marker_width = 2;
} else {
list_number = cmark_node_get_list_start(node->parent);
list_delim = cmark_node_get_list_delim(node->parent);
tmp = node;
while (tmp->prev) {
tmp = tmp->prev;
list_number += 1;
}
// we ensure a width of at least 4 so
// we get nice transition from single digits
// to double
snprintf(listmarker, 63, "%d%s%s", list_number,
list_delim == CMARK_PAREN_DELIM ?
")" : ".",
list_number < 10 ? " " : " ");
marker_width = strlen(listmarker);
}
if (entering) {
if (cmark_node_get_list_type(node->parent) ==
CMARK_BULLET_LIST) {
lit(state, "- ", false);
cmark_strbuf_puts(state->prefix, " ");
} else {
lit(state, listmarker, false);
for (i=marker_width; i--;) {
cmark_strbuf_putc(state->prefix, ' ');
}
}
} else {
cmark_strbuf_truncate(state->prefix,
state->prefix->size -
marker_width);
cr(state);
}
break;
case CMARK_NODE_HEADER:
if (entering) {
for (int i = cmark_node_get_header_level(node); i > 0; i--) {
lit(state, "#", false);
}
lit(state, " ", false);
state->no_wrap = true;
} else {
state->no_wrap = false;
blankline(state);
}
break;
case CMARK_NODE_CODE_BLOCK:
blankline(state);
info = cmark_node_get_fence_info(node);
code = &node->as.code.literal;
if ((info == NULL || strlen(info) == 0) &&
(code->len > 2 &&
!isspace(code->data[0]) &&
!(isspace(code->data[code->len - 1]) &&
isspace(code->data[code->len - 2])))) {
// use indented form if no info and code doesn't
// begin or end with a blank line
lit(state, " ", false);
cmark_strbuf_puts(state->prefix, " ");
out(state, node->as.code.literal, false, LITERAL);
cmark_strbuf_truncate(state->prefix,
state->prefix->size - 4);
} else {
numticks = longest_backtick_sequence(code) + 1;
if (numticks < 3) {
numticks = 3;
}
for (i = 0; i < numticks; i++) {
lit(state, "`", false);
}
lit(state, " ", false);
out(state, cmark_chunk_literal(info), false, LITERAL);
cr(state);
out(state, node->as.code.literal, false, NORMAL);
cr(state);
for (i = 0; i < numticks; i++) {
lit(state, "`", false);
}
}
blankline(state);
break;
case CMARK_NODE_HTML:
blankline(state);
out(state, node->as.literal, false, LITERAL);
blankline(state);
break;
case CMARK_NODE_HRULE:
blankline(state);
lit(state, "-----", false);
blankline(state);
break;
case CMARK_NODE_PARAGRAPH:
if (!entering) {
blankline(state);
}
break;
case CMARK_NODE_TEXT:
out(state, node->as.literal, true, NORMAL);
break;
case CMARK_NODE_LINEBREAK:
if (!(CMARK_OPT_HARDBREAKS & state->options)) {
lit(state, "\\", false);
}
cr(state);
break;
case CMARK_NODE_SOFTBREAK:
lit(state, " ", true);
break;
case CMARK_NODE_CODE:
code = &node->as.literal;
numticks = shortest_unused_backtick_sequence(code);
for (i = 0; i < numticks; i++) {
lit(state, "`", false);
}
if (code->data[0] == '`') {
lit(state, " ", false);
}
out(state, node->as.literal, true, LITERAL);
if (code->data[code->len - 1] == '`') {
lit(state, " ", false);
}
for (i = 0; i < numticks; i++) {
lit(state, "`", false);
}
break;
case CMARK_NODE_INLINE_HTML:
out(state, node->as.literal, true, LITERAL);
break;
case CMARK_NODE_STRONG:
if (entering) {
lit(state, "**", false);
} else {
lit(state, "**", false);
}
break;
case CMARK_NODE_EMPH:
// If we have EMPH(EMPH(x)), we need to use *_x_*
// because **x** is STRONG(x):
if (node->parent && node->parent->type == CMARK_NODE_EMPH &&
node->next == NULL && node->prev == NULL) {
emph_delim = "_";
} else {
emph_delim = "*";
}
if (entering) {
lit(state, emph_delim, false);
} else {
lit(state, emph_delim, false);
}
break;
case CMARK_NODE_LINK:
if (entering) {
lit(state, "[", false);
} else {
// TODO - emit autolink when url matches link text
// TODO - backslash-escape " and \ inside url, title
// for both links and images
lit(state, "](", false);
out(state, cmark_chunk_literal(cmark_node_get_url(node)), false, URL);
title = cmark_node_get_title(node);
if (title && strlen(title) > 0) {
lit(state, " \"", true);
out(state, cmark_chunk_literal(title), false, TITLE);
lit(state, "\"", false);
}
lit(state, ")", false);
}
break;
case CMARK_NODE_IMAGE:
if (entering) {
lit(state, "![", false);
} else {
lit(state, "](", false);
out(state, cmark_chunk_literal(cmark_node_get_url(node)), false, URL);
title = cmark_node_get_title(node);
if (title && strlen(title) > 0) {
lit(state, " \"", true);
out(state, cmark_chunk_literal(title), false, TITLE);
lit(state, "\"", false);
}
lit(state, ")", false);
}
break;
default:
assert(false);
break;
}
return 1;
}
char *cmark_render_commonmark(cmark_node *root, int options, int width)
{
char *result;
cmark_strbuf commonmark = GH_BUF_INIT;
cmark_strbuf prefix = GH_BUF_INIT;
if (CMARK_OPT_HARDBREAKS & options) {
width = 0;
}
struct render_state state =
{ options, &commonmark, &prefix, 0, width,
0, 0, true, false, false};
cmark_node *cur;
cmark_event_type ev_type;
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 *)cmark_strbuf_detach(&commonmark);
cmark_strbuf_free(&prefix);
cmark_iter_free(iter);
return result;
}
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