Update cmark-upstream to github/cmark-gfm@dcf6b38

ext/commonmarker/blocks.c

@@ -70,6 +70,22 @@ static void S_parser_feed(cmark_parser *parser, const unsigned char *buffer,
 static void S_process_line(cmark_parser *parser, const unsigned char *buffer,
                            bufsize_t bytes);
 
+static void subtract_open_block_counts(cmark_parser *parser, cmark_node *node) {
+  do {
+    decr_open_block_count(parser, S_type(node));
+    node->flags &= ~CMARK_NODE__OPEN_BLOCK;
+    node = node->last_child;
+  } while (node);
+}
+
+static void add_open_block_counts(cmark_parser *parser, cmark_node *node) {
+  do {
+    incr_open_block_count(parser, S_type(node));
+    node->flags |= CMARK_NODE__OPEN_BLOCK;
+    node = node->last_child;
+  } while (node);
+}
+
 static cmark_node *make_block(cmark_mem *mem, cmark_node_type tag,
                               int start_line, int start_column) {
   cmark_node *e;
@@ -129,6 +145,7 @@ static void cmark_parser_reset(cmark_parser *parser) {
   parser->refmap = cmark_reference_map_new(parser->mem);
   parser->root = document;
   parser->current = document;
+  add_open_block_counts(parser, document);
 
   parser->syntax_extensions = saved_exts;
   parser->inline_syntax_extensions = saved_inline_exts;
@@ -242,15 +259,18 @@ static void remove_trailing_blank_lines(cmark_strbuf *ln) {
 // Check to see if a node ends with a blank line, descending
 // if needed into lists and sublists.
 static bool S_ends_with_blank_line(cmark_node *node) {
-  if (S_last_line_checked(node)) {
-    return(S_last_line_blank(node));
-  } else if ((S_type(node) == CMARK_NODE_LIST ||
-              S_type(node) == CMARK_NODE_ITEM) && node->last_child) {
-    S_set_last_line_checked(node);
-    return(S_ends_with_blank_line(node->last_child));
-  } else {
-    S_set_last_line_checked(node);
-    return (S_last_line_blank(node));
+  while (true) {
+    if (S_last_line_checked(node)) {
+      return(S_last_line_blank(node));
+    } else if ((S_type(node) == CMARK_NODE_LIST ||
+                S_type(node) == CMARK_NODE_ITEM) && node->last_child) {
+      S_set_last_line_checked(node);
+      node = node->last_child;
+      continue;
+    } else {
+      S_set_last_line_checked(node);
+      return (S_last_line_blank(node));
+    }
   }
 }
 
@@ -310,6 +330,12 @@ static cmark_node *finalize(cmark_parser *parser, cmark_node *b) {
     has_content = resolve_reference_link_definitions(parser, b);
     if (!has_content) {
       // remove blank node (former reference def)
+      if (b->flags & CMARK_NODE__OPEN_BLOCK) {
+        decr_open_block_count(parser, S_type(b));
+        if (b->prev) {
+          add_open_block_counts(parser, b->prev);
+        }
+      }
       cmark_node_free(b);
     }
     break;
@@ -382,6 +408,17 @@ static cmark_node *finalize(cmark_parser *parser, cmark_node *b) {
   return parent;
 }
 
+// Recalculates the number of open blocks. Returns true if it matches what's currently stored
+// in parser. (Used to check that the counts in parser, which are updated incrementally, are
+// correct.)
+bool check_open_block_counts(cmark_parser *parser) {
+  cmark_parser tmp_parser = {0}; // Only used for its open_block_counts and total_open_blocks fields.
+  add_open_block_counts(&tmp_parser, parser->root);
+  return
+    tmp_parser.total_open_blocks == parser->total_open_blocks &&
+    memcmp(tmp_parser.open_block_counts, parser->open_block_counts, sizeof(parser->open_block_counts)) == 0;
+}
+
 // Add a node as child of another.  Return pointer to child.
 static cmark_node *add_child(cmark_parser *parser, cmark_node *parent,
                              cmark_node_type block_type, int start_column) {
@@ -400,11 +437,14 @@ static cmark_node *add_child(cmark_parser *parser, cmark_node *parent,
   if (parent->last_child) {
     parent->last_child->next = child;
     child->prev = parent->last_child;
+    subtract_open_block_counts(parser, parent->last_child);
   } else {
     parent->first_child = child;
     child->prev = NULL;
   }
   parent->last_child = child;
+  add_open_block_counts(parser, child);
+
   return child;
 }
 
@@ -1047,8 +1087,14 @@ static cmark_node *check_open_blocks(cmark_parser *parser, cmark_chunk *input,
   *all_matched = false;
   cmark_node *container = parser->root;
   cmark_node_type cont_type;
+  cmark_parser tmp_parser; // Only used for its open_block_counts and total_open_blocks fields.
+  memcpy(tmp_parser.open_block_counts, parser->open_block_counts, sizeof(parser->open_block_counts));
+  tmp_parser.total_open_blocks = parser->total_open_blocks;
+
+  assert(check_open_block_counts(parser));
 
   while (S_last_child_is_open(container)) {
+    decr_open_block_count(&tmp_parser, S_type(container));
     container = container->last_child;
     cont_type = S_type(container);
 
@@ -1060,6 +1106,53 @@ static cmark_node *check_open_blocks(cmark_parser *parser, cmark_chunk *input,
       continue;
     }
 
+    // This block of code is a workaround for the quadratic performance
+    // issue described here (issue 2):
+    //
+    // https://github.com/github/cmark-gfm/security/advisories/GHSA-66g8-4hjf-77xh
+    //
+    // If the current line is empty then we might be able to skip directly
+    // to the end of the list of open blocks. To determine whether this is
+    // possible, we have been maintaining a count of the number of
+    // different types of open blocks. The main criterium is that every
+    // remaining block, except the last element of the list, is a LIST or
+    // ITEM. The code below checks the conditions, and if they're ok, skips
+    // forward to parser->current.
+    if (parser->blank && parser->indent == 0) {  // Current line is empty
+      // Make sure that parser->current doesn't point to a closed block.
+      if (parser->current->flags & CMARK_NODE__OPEN_BLOCK) {
+        if (parser->current->flags & CMARK_NODE__OPEN) {
+          const size_t n_list = read_open_block_count(&tmp_parser, CMARK_NODE_LIST);
+          const size_t n_item = read_open_block_count(&tmp_parser, CMARK_NODE_ITEM);
+          // At most one block can be something other than a LIST or ITEM.
+          if (n_list + n_item + 1 >= tmp_parser.total_open_blocks) {
+            // Check that parser->current is suitable for jumping to.
+            switch (S_type(parser->current)) {
+            case CMARK_NODE_LIST:
+            case CMARK_NODE_ITEM:
+              if (n_list + n_item != tmp_parser.total_open_blocks) {
+                if (parser->current->last_child == NULL) {
+                  // There's another node type somewhere in the middle of
+                  // the list, so don't attempt the optimization.
+                  break;
+                }
+              }
+              // fall through
+            case CMARK_NODE_CODE_BLOCK:
+            case CMARK_NODE_PARAGRAPH:
+            case CMARK_NODE_HTML_BLOCK:
+              // Jump to parser->current
+              container = parser->current;
+              cont_type = S_type(container);
+              break;
+            default:
+              break;
+            }
+          }
+        }
+      }
+    }
+
     switch (cont_type) {
     case CMARK_NODE_BLOCK_QUOTE:
       if (!parse_block_quote_prefix(parser, input))
@@ -1193,8 +1286,9 @@ static void open_new_blocks(cmark_parser *parser, cmark_node **container,
       has_content = resolve_reference_link_definitions(parser, *container);
 
       if (has_content) {
-
-        (*container)->type = (uint16_t)CMARK_NODE_HEADING;
+        cmark_node_set_type(*container, CMARK_NODE_HEADING);
+        decr_open_block_count(parser, CMARK_NODE_PARAGRAPH);
+        incr_open_block_count(parser, CMARK_NODE_HEADING);
         (*container)->as.heading.level = lev;
         (*container)->as.heading.setext = true;
         S_advance_offset(parser, input, input->len - 1 - parser->offset, false);
@@ -1349,7 +1443,7 @@ static void add_text_to_container(cmark_parser *parser, cmark_node *container,
   S_set_last_line_blank(container, last_line_blank);
 
   tmp = container;
-  while (tmp->parent) {
+  while (tmp->parent && S_last_line_blank(tmp->parent)) {
     S_set_last_line_blank(tmp->parent, false);
     tmp = tmp->parent;
   }
@@ -1478,6 +1572,7 @@ static void S_process_line(cmark_parser *parser, const unsigned char *buffer,
 
   parser->line_number++;
 
+  assert(parser->current->next == NULL);
   last_matched_container = check_open_blocks(parser, &input, &all_matched);
 
   if (!last_matched_container)

ext/commonmarker/cmark-gfm.h

@@ -37,6 +37,16 @@ char *cmark_markdown_to_html(const char *text, size_t len, int options);
 #define CMARK_NODE_TYPE_MASK (0xc000)
 #define CMARK_NODE_VALUE_MASK (0x3fff)
 
+/**
+ * This is the maximum number of block types (CMARK_NODE_DOCUMENT,
+ * CMARK_NODE_HEADING, ...). It needs to be bigger than the number of
+ * hardcoded block types (below) to allow for extensions (see
+ * cmark_syntax_extension_add_node). But it also determines the size of the
+ * open_block_counts array in the cmark_parser struct, so we don't want it
+ * to be excessively large.
+ */
+#define CMARK_NODE_TYPE_BLOCK_LIMIT 0x20
+
 typedef enum {
   /* Error status */
   CMARK_NODE_NONE = 0x0000,

ext/commonmarker/cmark-gfm_version.h

@@ -1,7 +1,7 @@
 #ifndef CMARK_GFM_VERSION_H
 #define CMARK_GFM_VERSION_H
 
-#define CMARK_GFM_VERSION ((0 << 24) | (29 << 16) | (0 << 8) | 6)
-#define CMARK_GFM_VERSION_STRING "0.29.0.gfm.6"
+#define CMARK_GFM_VERSION ((0 << 24) | (29 << 16) | (0 << 8) | 10)
+#define CMARK_GFM_VERSION_STRING "0.29.0.gfm.10"
 
 #endif

ext/commonmarker/commonmark.c

@@ -153,23 +153,8 @@ static bool is_autolink(cmark_node *node) {
                   link_text->as.literal.len) == 0);
 }
 
-// if node is a block node, returns node.
-// otherwise returns first block-level node that is an ancestor of node.
-// if there is no block-level ancestor, returns NULL.
-static cmark_node *get_containing_block(cmark_node *node) {
-  while (node) {
-    if (CMARK_NODE_BLOCK_P(node)) {
-      return node;
-    } else {
-      node = node->parent;
-    }
-  }
-  return NULL;
-}
-
 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;
   int numticks;
@@ -189,14 +174,17 @@ static int S_render_node(cmark_renderer *renderer, cmark_node *node,
   // Don't adjust tight list status til we've started the list.
   // Otherwise we loose the blank line between a paragraph and
   // a following list.
-  if (!(node->type == CMARK_NODE_ITEM && node->prev == NULL && entering)) {
-    tmp = get_containing_block(node);
-    renderer->in_tight_list_item =
-        tmp && // tmp might be NULL if there is no containing block
-        ((tmp->type == CMARK_NODE_ITEM &&
-          cmark_node_get_list_tight(tmp->parent)) ||
-         (tmp && tmp->parent && tmp->parent->type == CMARK_NODE_ITEM &&
-          cmark_node_get_list_tight(tmp->parent->parent)));
+  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;
+    }
   }
 
   if (node->extension && node->extension->commonmark_render_func) {
@@ -228,19 +216,15 @@ static int S_render_node(cmark_renderer *renderer, cmark_node *node,
       LIT("<!-- end list -->");
       BLANKLINE();
     }
+    renderer->list_number = cmark_node_get_list_start(node);
     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_number = renderer->list_number++;
       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
@@ -405,10 +389,12 @@ static int S_render_node(cmark_renderer *renderer, cmark_node *node,
     break;
 
   case CMARK_NODE_STRONG:
-    if (entering) {
-      LIT("**");
-    } else {
-      LIT("**");
+    if (node->parent == NULL || node->parent->type != CMARK_NODE_STRONG) {
+      if (entering) {
+        LIT("**");
+      } else {
+        LIT("**");
+      }
     }
     break;
 

ext/commonmarker/html.c

@@ -364,10 +364,12 @@ static int S_render_node(cmark_html_renderer *renderer, cmark_node *node,
     break;
 
   case CMARK_NODE_STRONG:
-    if (entering) {
-      cmark_strbuf_puts(html, "<strong>");
-    } else {
-      cmark_strbuf_puts(html, "</strong>");
+    if (node->parent == NULL || node->parent->type != CMARK_NODE_STRONG) {
+      if (entering) {
+        cmark_strbuf_puts(html, "<strong>");
+      } else {
+        cmark_strbuf_puts(html, "</strong>");
+      }
     }
     break;
 

ext/commonmarker/latex.c

@@ -385,10 +385,12 @@ static int S_render_node(cmark_renderer *renderer, cmark_node *node,
     break;
 
   case CMARK_NODE_STRONG:
-    if (entering) {
-      LIT("\\textbf{");
-    } else {
-      LIT("}");
+    if (node->parent == NULL || node->parent->type != CMARK_NODE_STRONG) {
+      if (entering) {
+        LIT("\\textbf{");
+      } else {
+        LIT("}");
+      }
     }
     break;