Fix backtick algorithm

now it more closely matches one in `cmark`

lib/rules_inline/backticks.js

@@ -3,17 +3,8 @@
 'use strict';
 
 
-function addCodeToken(state, marker, pos, matchStart) {
-  var token     = state.push('code_inline', 'code', 0);
-  token.markup  = marker;
-  token.content = state.src.slice(pos, matchStart)
-    .replace(/\n/g, ' ')
-    .replace(/^ (.+) $/, '$1');
-}
-
-
 module.exports = function backtick(state, silent) {
-  var start, max, marker, matchStart, matchEnd, startLength, endLength,
+  var start, max, marker, token, matchStart, matchEnd, openerLength, closerLength,
       pos = state.pos,
       ch = state.src.charCodeAt(pos);
 
@@ -27,17 +18,11 @@ module.exports = function backtick(state, silent) {
   while (pos < max && state.src.charCodeAt(pos) === 0x60/* ` */) { pos++; }
 
   marker = state.src.slice(start, pos);
-  startLength = marker.length;
-
-  // Look for required marker length in the cache first
-  if (state.backticks[startLength] && state.backticks[startLength] > start) {
-    if (state.backticks[startLength] === Infinity) {
-      if (!silent) state.pending += marker;
-      state.pos += startLength;
-    } else {
-      if (!silent) addCodeToken(state, marker, pos, state.backticks[startLength]);
-      state.pos = matchEnd;
-    }
+  openerLength = marker.length;
+
+  if (state.backticksScanned && (state.backticks[openerLength] || 0) <= start) {
+    if (!silent) state.pending += marker;
+    state.pos += openerLength;
     return true;
   }
 
@@ -50,27 +35,31 @@ module.exports = function backtick(state, silent) {
     // scan marker length
     while (matchEnd < max && state.src.charCodeAt(matchEnd) === 0x60/* ` */) { matchEnd++; }
 
-    endLength = matchEnd - matchStart;
+    closerLength = matchEnd - matchStart;
 
-    if (endLength === marker.length) {
+    if (closerLength === openerLength) {
       // Found matching closer length.
-      if (!silent) addCodeToken(state, marker, pos, matchStart);
+      if (!silent) {
+        token     = state.push('code_inline', 'code', 0);
+        token.markup  = marker;
+        token.content = state.src.slice(pos, matchStart)
+          .replace(/\n/g, ' ')
+          .replace(/^ (.+) $/, '$1');
+      }
       state.pos = matchEnd;
       return true;
     }
 
-    // Some different length found, put it in cache just in case
-    if (!state.backticks[endLength] || state.backticks[endLength] <= start) {
-      state.backticks[endLength] = matchStart;
-    }
+    // Some different length found, put it in cache as upper limit of where closer can be found
+    state.backticks[closerLength] = matchStart;
 
-    // Scanned through the end, didn't find anything. Mark "no matches" for this length;
+    // Scanned through the end, didn't find anything
     if (matchEnd >= max) {
-      state.backticks[startLength] = Infinity;
+      state.backticksScanned = true;
     }
   }
 
   if (!silent) state.pending += marker;
-  state.pos += startLength;
+  state.pos += openerLength;
   return true;
 };

lib/rules_inline/state_inline.js

@@ -34,6 +34,7 @@ function StateInline(src, md, env, outTokens) {
 
   // backtick length => last seen position
   this.backticks = {};
+  this.backticksScanned = false;
 }
 
 

test/fixtures/markdown-it/commonmark_extras.txt

@@ -304,6 +304,14 @@ Coverage. Unpaired nested backtick (silent mode)
 .
 
 
+Coverage. Should continue scanning after closing "```" despite cache
+.
+```aaa``bbb``ccc```ddd``eee``
+.
+<p><code>aaa``bbb``ccc</code>ddd<code>eee</code></p>
+.
+
+
 Coverage. Entities.
 .
 *&*