add new spoiler extension

extensions/core-extensions.c

@@ -2,6 +2,7 @@
 #include "autolink.h"
 #include "mutex.h"
 #include "strikethrough.h"
+#include "spoiler.h"
 #include "table.h"
 #include "tagfilter.h"
 #include "tasklist.h"
@@ -15,6 +16,7 @@ static int core_extensions_registration(cmark_plugin *plugin) {
   cmark_plugin_register_syntax_extension(plugin, create_autolink_extension());
   cmark_plugin_register_syntax_extension(plugin, create_tagfilter_extension());
   cmark_plugin_register_syntax_extension(plugin, create_tasklist_extension());
+  cmark_plugin_register_syntax_extension(plugin, create_spoiler_extension());
   return 1;
 }
 

extensions/spoiler.c

@@ -0,0 +1,139 @@
+#include "spoiler.h"
+#include <parser.h>
+#include <render.h>
+
+cmark_node_type CMARK_NODE_SPOILER;
+
+static cmark_node *match(cmark_syntax_extension *self, cmark_parser *parser,
+                         cmark_node *parent, unsigned char character,
+                         cmark_inline_parser *inline_parser) {
+  cmark_node *res = NULL;
+  int left_flanking, right_flanking, punct_before, punct_after, delims;
+  char buffer[101];
+
+  if (character != '|')
+    return NULL;
+
+  delims = cmark_inline_parser_scan_delimiters(
+      inline_parser, sizeof(buffer) - 1, '|',
+      &left_flanking,
+      &right_flanking, &punct_before, &punct_after);
+
+  memset(buffer, '|', delims);
+  buffer[delims] = 0;
+
+  res = cmark_node_new_with_mem(CMARK_NODE_TEXT, parser->mem);
+  cmark_node_set_literal(res, buffer);
+  res->start_line = res->end_line = cmark_inline_parser_get_line(inline_parser);
+  res->start_column = cmark_inline_parser_get_column(inline_parser) - delims;
+
+  if ((left_flanking || right_flanking) && (delims == 2)) {
+    cmark_inline_parser_push_delimiter(inline_parser, character, left_flanking,
+                                       right_flanking, res);
+  }
+
+  return res;
+}
+
+static delimiter *insert(cmark_syntax_extension *self, cmark_parser *parser,
+                         cmark_inline_parser *inline_parser, delimiter *opener,
+                         delimiter *closer) {
+  cmark_node *spoiler;
+  cmark_node *tmp, *next;
+  delimiter *delim, *tmp_delim;
+  delimiter *res = closer->next;
+
+  spoiler = opener->inl_text;
+
+  if (opener->inl_text->as.literal.len != closer->inl_text->as.literal.len)
+    goto done;
+
+  if (!cmark_node_set_type(spoiler, CMARK_NODE_SPOILER))
+    goto done;
+
+  cmark_node_set_syntax_extension(spoiler, self);
+
+  tmp = cmark_node_next(opener->inl_text);
+
+  while (tmp) {
+    if (tmp == closer->inl_text)
+      break;
+    next = cmark_node_next(tmp);
+    cmark_node_append_child(spoiler, tmp);
+    tmp = next;
+  }
+
+  spoiler->end_column = closer->inl_text->start_column + closer->inl_text->as.literal.len - 1;
+  cmark_node_free(closer->inl_text);
+
+  delim = closer;
+  while (delim != NULL && delim != opener) {
+    tmp_delim = delim->previous;
+    cmark_inline_parser_remove_delimiter(inline_parser, delim);
+    delim = tmp_delim;
+  }
+
+  cmark_inline_parser_remove_delimiter(inline_parser, opener);
+
+done:
+  return res;
+}
+
+static const char *get_type_string(cmark_syntax_extension *extension,
+                                   cmark_node *node) {
+  return node->type == CMARK_NODE_SPOILER ? "spoiler" : "<unknown>";
+}
+
+static int can_contain(cmark_syntax_extension *extension, cmark_node *node,
+                       cmark_node_type child_type) {
+  if (node->type != CMARK_NODE_SPOILER)
+    return false;
+
+  return CMARK_NODE_TYPE_INLINE_P(child_type);
+}
+
+static void commonmark_render(cmark_syntax_extension *extension,
+                              cmark_renderer *renderer, cmark_node *node,
+                              cmark_event_type ev_type, int options) {
+  renderer->out(renderer, node, "||", false, LITERAL);
+}
+
+static void html_render(cmark_syntax_extension *extension,
+                        cmark_html_renderer *renderer, cmark_node *node,
+                        cmark_event_type ev_type, int options) {
+  bool entering = (ev_type == CMARK_EVENT_ENTER);
+  if (entering) {
+    cmark_strbuf_puts(renderer->html, "<span class=\"spoiler\">");
+  } else {
+    cmark_strbuf_puts(renderer->html, "</span>");
+  }
+}
+
+static void plaintext_render(cmark_syntax_extension *extension,
+                             cmark_renderer *renderer, cmark_node *node,
+                             cmark_event_type ev_type, int options) {
+  renderer->out(renderer, node, "~", false, LITERAL);
+}
+
+cmark_syntax_extension *create_spoiler_extension(void) {
+  cmark_syntax_extension *ext = cmark_syntax_extension_new("spoiler");
+  cmark_llist *special_chars = NULL;
+
+  cmark_syntax_extension_set_get_type_string_func(ext, get_type_string);
+  cmark_syntax_extension_set_can_contain_func(ext, can_contain);
+  cmark_syntax_extension_set_commonmark_render_func(ext, commonmark_render);
+  cmark_syntax_extension_set_html_render_func(ext, html_render);
+  cmark_syntax_extension_set_plaintext_render_func(ext, plaintext_render);
+  CMARK_NODE_SPOILER = cmark_syntax_extension_add_node(1);
+
+  cmark_syntax_extension_set_match_inline_func(ext, match);
+  cmark_syntax_extension_set_inline_from_delim_func(ext, insert);
+
+  cmark_mem *mem = cmark_get_default_mem_allocator();
+  special_chars = cmark_llist_append(mem, special_chars, (void *)'|');
+  cmark_syntax_extension_set_special_inline_chars(ext, special_chars);
+
+  cmark_syntax_extension_set_emphasis(ext, 1);
+
+  return ext;
+}

extensions/spoiler.h

@@ -0,0 +1,9 @@
+#ifndef CMARK_GFM_SPOILER_H
+#define CMARK_GFM_SPOILER_H
+
+#include "cmark-gfm-core-extensions.h"
+
+extern cmark_node_type CMARK_NODE_SPOILER;
+cmark_syntax_extension *create_spoiler_extension(void);
+
+#endif /* CMARK_GFM_SPOILER_H */