Add 'cmark/' from commit '64efa3b3b3d35f2ffb604b57a8a9c89047cb420b'

git-subtree-dir: cmark
git-subtree-mainline: 6bf7c5ce92ff6237c0b17c332873805018812b40
git-subtree-split: 64efa3b3b3d35f2ffb604b57a8a9c89047cb420b

1 files changed, 473 insertions, 0 deletions

diff --git a/cmark/src/commonmark.c b/cmark/src/commonmark.c
new file mode 100644
index 0000000000..ad805a630e
--- /dev/null
+++ b/cmark/src/commonmark.c
@@ -0,0 +1,473 @@
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "cmark.h"
+#include "node.h"
+#include "buffer.h"
+#include "utf8.h"
+#include "scanners.h"
+#include "render.h"
+
+#define OUT(s, wrap, escaping) renderer->out(renderer, s, wrap, escaping)
+#define LIT(s) renderer->out(renderer, s, false, LITERAL)
+#define CR() renderer->cr(renderer)
+#define BLANKLINE() renderer->blankline(renderer)
+#define ENCODED_SIZE 20
+#define LISTMARKER_SIZE 20
+
+// Functions to convert cmark_nodes to commonmark strings.
+
+static inline void outc(cmark_renderer *renderer, cmark_escaping escape,
+                        int32_t c, unsigned char nextc) {
+  bool needs_escaping = false;
+  bool follows_digit =
+      renderer->buffer->size > 0 &&
+      cmark_isdigit(renderer->buffer->ptr[renderer->buffer->size - 1]);
+  char encoded[ENCODED_SIZE];
+  int options = renderer->options;
+
+  needs_escaping =
+      c < 0x80 && escape != LITERAL &&
+      ((escape == NORMAL &&
+        (c < 0x20 ||
+         c == '*' || c == '_' || c == '[' || c == ']' || c == '#' || c == '<' ||
+         c == '>' || c == '\\' || c == '`' ||
+	 (c == '!' && (!nextc || nextc == '[')) ||
+         (c == '&' && cmark_isalpha(nextc)) || (c == '!' && nextc == '[') ||
+         ((CMARK_OPT_SMART & options) &&
+            ((c == '-' && nextc == '-') ||
+             (c == '.' && nextc == '.') ||
+             c == '"' || c == '\'')) ||
+         (renderer->begin_content && (c == '-' || c == '+' || c == '=') &&
+          // begin_content doesn't get set to false til we've passed digits
+          // at the beginning of line, so...
+          !follows_digit) ||
+         (renderer->begin_content && (c == '.' || c == ')') && follows_digit &&
+          (nextc == 0 || cmark_isspace(nextc))))) ||
+       (escape == URL &&
+        (c == '`' || c == '<' || c == '>' || cmark_isspace(c) || c == '\\' ||
+         c == ')' || c == '(')) ||
+       (escape == TITLE &&
+        (c == '`' || c == '<' || c == '>' || c == '"' || c == '\\')));
+
+  if (needs_escaping) {
+    if (escape == URL && cmark_isspace(c)) {
+      // use percent encoding for spaces
+      snprintf(encoded, ENCODED_SIZE, "%%%2X", c);
+      cmark_strbuf_puts(renderer->buffer, encoded);
+      renderer->column += 3;
+    } else if (cmark_ispunct(c)) {
+      cmark_render_ascii(renderer, "\\");
+      cmark_render_code_point(renderer, c);
+    } else { // render as entity
+      snprintf(encoded, ENCODED_SIZE, "&#%d;", c);
+      cmark_strbuf_puts(renderer->buffer, encoded);
+      renderer->column += (int)strlen(encoded);
+    }
+  } else {
+    cmark_render_code_point(renderer, c);
+  }
+}
+
+static int longest_backtick_sequence(const char *code) {
+  int longest = 0;
+  int current = 0;
+  size_t i = 0;
+  size_t code_len = strlen(code);
+  while (i <= code_len) {
+    if (code[i] == '`') {
+      current++;
+    } else {
+      if (current > longest) {
+        longest = current;
+      }
+      current = 0;
+    }
+    i++;
+  }
+  return longest;
+}
+
+static int shortest_unused_backtick_sequence(const char *code) {
+  // note: if the shortest sequence is >= 32, this returns 32
+  // so as not to overflow the bit array.
+  uint32_t used = 1;
+  int current = 0;
+  size_t i = 0;
+  size_t code_len = strlen(code);
+  while (i <= code_len) {
+    if (code[i] == '`') {
+      current++;
+    } else {
+      if (current > 0 && current < 32) {
+        used |= (1U << current);
+      }
+      current = 0;
+    }
+    i++;
+  }
+  // return number of first bit that is 0:
+  i = 0;
+  while (i < 32 && used & 1) {
+    used = used >> 1;
+    i++;
+  }
+  return (int)i;
+}
+
+static bool is_autolink(cmark_node *node) {
+  const unsigned char *title;
+  const unsigned char *url;
+  cmark_node *link_text;
+
+  if (node->type != CMARK_NODE_LINK) {
+    return false;
+  }
+
+  url = node->as.link.url;
+  if (url == NULL || _scan_scheme(url) == 0) {
+    return false;
+  }
+
+  title = node->as.link.title;
+  // if it has a title, we can't treat it as an autolink:
+  if (title && title[0]) {
+    return false;
+  }
+
+  link_text = node->first_child;
+  if (link_text == NULL) {
+    return false;
+  }
+  cmark_consolidate_text_nodes(link_text);
+  if (strncmp((const char *)url, "mailto:", 7) == 0) {
+    url += 7;
+  }
+  return link_text->data != NULL &&
+         strcmp((const char *)url, (char *)link_text->data) == 0;
+}
+
+static int S_render_node(cmark_renderer *renderer, cmark_node *node,
+                         cmark_event_type ev_type, int options) {
+  cmark_node *tmp;
+  int list_number;
+  cmark_delim_type list_delim;
+  size_t numticks;
+  bool extra_spaces;
+  size_t i;
+  bool entering = (ev_type == CMARK_EVENT_ENTER);
+  const char *info, *code, *title;
+  char fencechar[2] = {'\0', '\0'};
+  size_t code_len;
+  char listmarker[LISTMARKER_SIZE];
+  const char *emph_delim;
+  bool first_in_list_item;
+  bufsize_t marker_width;
+  bool has_nonspace;
+  bool allow_wrap = renderer->width > 0 && !(CMARK_OPT_NOBREAKS & options) &&
+                    !(CMARK_OPT_HARDBREAKS & options);
+
+  // Don't adjust tight list status til we've started the list.
+  // Otherwise we lose the blank line between a paragraph and
+  // a following list.
+  if (entering) {
+    if (node->parent && node->parent->type == CMARK_NODE_ITEM) {
+      renderer->in_tight_list_item = node->parent->parent->as.list.tight;
+    }
+  } else {
+    if (node->type == CMARK_NODE_LIST) {
+      renderer->in_tight_list_item =
+        node->parent &&
+        node->parent->type == CMARK_NODE_ITEM &&
+        node->parent->parent->as.list.tight;
+    }
+  }
+
+  switch (node->type) {
+  case CMARK_NODE_DOCUMENT:
+    break;
+
+  case CMARK_NODE_BLOCK_QUOTE:
+    if (entering) {
+      LIT("> ");
+      renderer->begin_content = true;
+      cmark_strbuf_puts(renderer->prefix, "> ");
+    } else {
+      cmark_strbuf_truncate(renderer->prefix, renderer->prefix->size - 2);
+      BLANKLINE();
+    }
+    break;
+
+  case CMARK_NODE_LIST:
+    if (!entering && node->next && (node->next->type == CMARK_NODE_LIST)) {
+      // this ensures that a following indented code block or list will be
+      // inteprereted correctly.
+      CR();
+      LIT("<!-- end list -->");
+      BLANKLINE();
+    }
+    break;
+
+  case CMARK_NODE_ITEM:
+    if (cmark_node_get_list_type(node->parent) == CMARK_BULLET_LIST) {
+      marker_width = 4;
+    } 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, LISTMARKER_SIZE, "%d%s%s", list_number,
+               list_delim == CMARK_PAREN_DELIM ? ")" : ".",
+               list_number < 10 ? "  " : " ");
+      marker_width = (bufsize_t)strlen(listmarker);
+    }
+    if (entering) {
+      if (cmark_node_get_list_type(node->parent) == CMARK_BULLET_LIST) {
+        LIT("  - ");
+        renderer->begin_content = true;
+      } else {
+        LIT(listmarker);
+        renderer->begin_content = true;
+      }
+      if (node->first_child == NULL) {
+        BLANKLINE();
+      } else {
+        for (i = marker_width; i--;) {
+          cmark_strbuf_putc(renderer->prefix, ' ');
+        }
+      }
+    } else {
+      cmark_strbuf_truncate(renderer->prefix,
+                            renderer->prefix->size - marker_width);
+      CR();
+    }
+    break;
+
+  case CMARK_NODE_HEADING:
+    if (entering) {
+      for (i = cmark_node_get_heading_level(node); i > 0; i--) {
+        LIT("#");
+      }
+      LIT(" ");
+      renderer->begin_content = true;
+      renderer->no_linebreaks = true;
+    } else {
+      renderer->no_linebreaks = false;
+      BLANKLINE();
+    }
+    break;
+
+  case CMARK_NODE_CODE_BLOCK:
+
+    first_in_list_item = node->prev == NULL && node->parent &&
+                         node->parent->type == CMARK_NODE_ITEM;
+
+    if (!first_in_list_item) {
+      BLANKLINE();
+    }
+    info = cmark_node_get_fence_info(node);
+    fencechar[0] = strchr(info, '`') == NULL ? '`' : '~';
+    code = cmark_node_get_literal(node);
+
+    numticks = longest_backtick_sequence(code) + 1;
+    if (numticks < 3) {
+      numticks = 3;
+    }
+    for (i = 0; i < numticks; i++) {
+      LIT(fencechar);
+    }
+    LIT(" ");
+    OUT(info, false, LITERAL);
+    CR();
+    OUT(cmark_node_get_literal(node), false, LITERAL);
+    CR();
+    for (i = 0; i < numticks; i++) {
+      LIT(fencechar);
+    }
+
+    BLANKLINE();
+    break;
+
+  case CMARK_NODE_HTML_BLOCK:
+    BLANKLINE();
+    OUT(cmark_node_get_literal(node), false, LITERAL);
+    BLANKLINE();
+    break;
+
+  case CMARK_NODE_CUSTOM_BLOCK:
+    BLANKLINE();
+    OUT(entering ? cmark_node_get_on_enter(node) : cmark_node_get_on_exit(node),
+        false, LITERAL);
+    BLANKLINE();
+    break;
+
+  case CMARK_NODE_THEMATIC_BREAK:
+    BLANKLINE();
+    LIT("-----");
+    BLANKLINE();
+    break;
+
+  case CMARK_NODE_PARAGRAPH:
+    if (!entering) {
+      BLANKLINE();
+    }
+    break;
+
+  case CMARK_NODE_TEXT:
+    OUT(cmark_node_get_literal(node), allow_wrap, NORMAL);
+    break;
+
+  case CMARK_NODE_LINEBREAK:
+    if (!(CMARK_OPT_HARDBREAKS & options)) {
+      LIT("  ");
+    }
+    CR();
+    break;
+
+  case CMARK_NODE_SOFTBREAK:
+    if (CMARK_OPT_HARDBREAKS & options) {
+      LIT("  ");
+      CR();
+    } else if (!renderer->no_linebreaks && renderer->width == 0 &&
+               !(CMARK_OPT_HARDBREAKS & options) &&
+               !(CMARK_OPT_NOBREAKS & options)) {
+      CR();
+    } else {
+      OUT(" ", allow_wrap, LITERAL);
+    }
+    break;
+
+  case CMARK_NODE_CODE:
+    code = cmark_node_get_literal(node);
+    code_len = strlen(code);
+    numticks = shortest_unused_backtick_sequence(code);
+    has_nonspace = false;
+    for (i=0; i < code_len; i++) {
+      if (code[i] != ' ') {
+        has_nonspace = true;
+        break;
+      }
+    }
+    extra_spaces = code_len == 0 ||
+            code[0] == '`' || code[code_len - 1] == '`' ||
+            (has_nonspace && code[0] == ' ' && code[code_len - 1] == ' ');
+    for (i = 0; i < numticks; i++) {
+      LIT("`");
+    }
+    if (extra_spaces) {
+      LIT(" ");
+    }
+    OUT(cmark_node_get_literal(node), allow_wrap, LITERAL);
+    if (extra_spaces) {
+      LIT(" ");
+    }
+    for (i = 0; i < numticks; i++) {
+      LIT("`");
+    }
+    break;
+
+  case CMARK_NODE_HTML_INLINE:
+    OUT(cmark_node_get_literal(node), false, LITERAL);
+    break;
+
+  case CMARK_NODE_CUSTOM_INLINE:
+    OUT(entering ? cmark_node_get_on_enter(node) : cmark_node_get_on_exit(node),
+        false, LITERAL);
+    break;
+
+  case CMARK_NODE_STRONG:
+    if (entering) {
+      LIT("**");
+    } else {
+      LIT("**");
+    }
+    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(emph_delim);
+    } else {
+      LIT(emph_delim);
+    }
+    break;
+
+  case CMARK_NODE_LINK:
+    if (is_autolink(node)) {
+      if (entering) {
+        LIT("<");
+        if (strncmp(cmark_node_get_url(node), "mailto:", 7) == 0) {
+          LIT((const char *)cmark_node_get_url(node) + 7);
+        } else {
+          LIT((const char *)cmark_node_get_url(node));
+        }
+        LIT(">");
+        // return signal to skip contents of node...
+        return 0;
+      }
+    } else {
+      if (entering) {
+        LIT("[");
+      } else {
+        LIT("](");
+        OUT(cmark_node_get_url(node), false, URL);
+        title = cmark_node_get_title(node);
+        if (strlen(title) > 0) {
+          LIT(" \"");
+          OUT(title, false, TITLE);
+          LIT("\"");
+        }
+        LIT(")");
+      }
+    }
+    break;
+
+  case CMARK_NODE_IMAGE:
+    if (entering) {
+      LIT("![");
+    } else {
+      LIT("](");
+      OUT(cmark_node_get_url(node), false, URL);
+      title = cmark_node_get_title(node);
+      if (strlen(title) > 0) {
+        OUT(" \"", allow_wrap, LITERAL);
+        OUT(title, false, TITLE);
+        LIT("\"");
+      }
+      LIT(")");
+    }
+    break;
+
+  default:
+    assert(false);
+    break;
+  }
+
+  return 1;
+}
+
+char *cmark_render_commonmark(cmark_node *root, int options, int width) {
+  if (options & CMARK_OPT_HARDBREAKS) {
+    // disable breaking on width, since it has
+    // a different meaning with OPT_HARDBREAKS
+    width = 0;
+  }
+  return cmark_render(root, options, width, outc, S_render_node);
+}