From 6c57203ae5c7d85715e5c8a4e9055406f2822a6e Mon Sep 17 00:00:00 2001
From: David Anson <david@dlaa.me>
Date: Thu, 10 Jan 2019 21:29:27 -0800
Subject: [PATCH] Use tokens (vs. RegExp) for identifying fenced code blocks
 (fixes #151, fixes #152, fixes #155).

---
 lib/shared.js                 | 39 ++++++++++++++++-------------------
 test/fenced-code-in-list.json |  6 ++++++
 test/fenced-code-in-list.md   | 35 +++++++++++++++++++++++++++++++
 test/fenced-code-unmatched.md | 13 ++++++++++++
 4 files changed, 72 insertions(+), 21 deletions(-)
 create mode 100644 test/fenced-code-in-list.json
 create mode 100644 test/fenced-code-in-list.md
 create mode 100644 test/fenced-code-unmatched.md

diff --git a/lib/shared.js b/lib/shared.js
index e7d063b3..73a547db 100644
--- a/lib/shared.js
+++ b/lib/shared.js
@@ -136,32 +136,26 @@ function makeTokenCache(params) {
     return;
   }
 
-  // Populate line metadata array
+  // Initialize line metadata array
+  //   0x7: inCode
+  //     0x6: onFence (start)
+  //     0x2: onFence (end)
+  //     0x1: code body
+  //   0x8: inTable
   const lineMetadata = new Array(params.lines.length);
-  let fenceStart = null;
-  let inFence = false;
-  // Find fenced code by pattern (parser ignores "``` close fence")
-  params.lines.forEach(function forLine(line, lineIndex) {
-    let metadata = 0;
-    const match = /^[ ]{0,3}(`{3,}|~{3,})/.exec(line);
-    const fence = match && match[1];
-    if (fence &&
-        (!inFence || (fence.substr(0, fenceStart.length) === fenceStart))) {
-      metadata = inFence ? 2 : 6;
-      fenceStart = inFence ? null : fence;
-      inFence = !inFence;
-    } else if (inFence) {
-      metadata = 1;
+  lineMetadata.fill(0);
+  filterTokens(params, "fence", function forToken(token) {
+    lineMetadata[token.map[0]] = 6;
+    lineMetadata[token.map[1] - 1] = 2;
+    for (let i = token.map[0] + 1; i < token.map[1] - 1; i++) {
+      lineMetadata[i] = 1;
     }
-    lineMetadata[lineIndex] = metadata;
   });
-  // Find code blocks normally
   filterTokens(params, "code_block", function forToken(token) {
     for (let i = token.map[0]; i < token.map[1]; i++) {
       lineMetadata[i] = 1;
     }
   });
-  // Find tables normally
   filterTokens(params, "table_open", function forToken(token) {
     for (let i = token.map[0]; i < token.map[1]; i++) {
       lineMetadata[i] += 8;
@@ -220,12 +214,15 @@ module.exports.forEachLine = function forEachLine(callback) {
   // Invoke callback
   tokenCache.params.lines.forEach(function forLine(line, lineIndex) {
     const metadata = tokenCache.lineMetadata[lineIndex];
+    const inCode = !!(metadata & 7);
+    const onFence = (((metadata & 6) >> 1) || 2) - 2;
+    const inTable = !!(metadata & 8);
     callback(
       line,
       lineIndex,
-      !!(metadata & 7),
-      (((metadata & 6) >> 1) || 2) - 2,
-      !!(metadata & 8));
+      inCode,
+      onFence,
+      inTable);
   });
 };
 
diff --git a/test/fenced-code-in-list.json b/test/fenced-code-in-list.json
new file mode 100644
index 00000000..b6ba1058
--- /dev/null
+++ b/test/fenced-code-in-list.json
@@ -0,0 +1,6 @@
+{
+  "default": true,
+  "MD013": {
+    "code_blocks": false
+  }
+}
diff --git a/test/fenced-code-in-list.md b/test/fenced-code-in-list.md
new file mode 100644
index 00000000..df8f5f08
--- /dev/null
+++ b/test/fenced-code-in-list.md
@@ -0,0 +1,35 @@
+# Heading
+
+- Item
+
+  ```javascript
+  debugger;
+
+
+  debugger;
+  ```
+
+  text
+
+- Item
+
+  - Subitem
+
+    ```javascript
+    debugger;
+
+
+    debugger;
+    ```
+
+    text
+
+  - Subitem
+
+- Item
+
+  - Subitem
+
+    ```javascript
+    debugger; debugger; debugger; debugger; debugger; debugger; debugger; debugger; debugger; debugger;
+    ```
diff --git a/test/fenced-code-unmatched.md b/test/fenced-code-unmatched.md
new file mode 100644
index 00000000..20827215
--- /dev/null
+++ b/test/fenced-code-unmatched.md
@@ -0,0 +1,13 @@
+# Heading
+
+Text
+
+```code```
+
+Text
+
+```javascript
+var x = 5;
+```
+
+Text