refactor codeblock to new event system

docs/event_system.md

@@ -74,11 +74,14 @@ Usually you would want to use this event if you wish to modify the subparser beh
 of the subparser.
 
 **IMPORTANT NOTE**: Extensions listening to onCapture event should try to AVOID changing the output property.
-Instead, they should modify the values of the matches and attributes arrays. This is because 
-the **output property takes precedence over the matches array**, which means 2 very important things:
+Instead, they should modify the values of the matches and attributes objects. This is because 
+the **output property takes precedence over the matches objects** and **prevents showdown to call other subparsers**
+inside the captured fragment.This means 3 very important things:
 
- 1. If something is passed as the output property, any changes to the matches array will be ignored.
- 2. Point 1 includes other extensions that listen to the same event.
+ 1. If something is passed as the output property, any changes to the matches and attributes objects will be ignored.
+ 2. Changes made by other extensions to the matches or attributes objects will also be ignored
+ 3. Showdown will not call other subparsers, such as encode code or span gamut in the text fragment, which may lead to
+    weird results.
 
 ```javascript
 // showdown extension 1 that is listening to makehtml.blockquote.onCapture

src/helpers.js

@@ -61,6 +61,22 @@ showdown.helper.isUndefined = function (value) {
   return typeof value === 'undefined';
 };
 
+/**
+ * Check if value is an object (excluding arrays)
+ * @param {*} value
+ * @returns {boolean}
+ */
+showdown.helper.isObject = function (value) {
+  'use strict';
+  return (
+    typeof value === 'object' &&
+    !Array.isArray(value) &&
+    value !== null
+  );
+}
+
+
+
 /**
  * ForEach helper function
  * Iterates over Arrays and Objects (own properties only)
@@ -551,6 +567,24 @@ showdown.helper.cloneObject = function (obj, deep) {
   }
 };
 
+/**
+ * Populate attributes in output text
+ * @param {string} text
+ * @param {{}} attributes
+ * @returns {string}
+ */
+showdown.helper._populateAttributes = function (attributes) {
+  let text = '';
+  if (attributes && showdown.helper.isObject(attributes)) {
+    for (let attr in attributes) {
+      if (attributes.hasOwnProperty(attr)) {
+        text += ' ' + attr + '=' + attributes[attr];
+      }
+    }
+  }
+  return text;
+};
+
 showdown.helper.Event = class {
 
   /**

src/subParsers/makehtml/blockQuotes.js

@@ -75,13 +75,7 @@ showdown.subParser('makehtml.blockQuotes', function (text, options, globals) {
         return pre;
       });
       attributes = captureStartEvent.attributes;
-      otp = '<blockquote';
-      for (let attr in attributes) {
-        if (attributes.hasOwnProperty(attr)) {
-          otp += ' ' + attr + '=' + attributes[attr];
-        }
-      }
-      otp += '>\n' + bq + '\n</blockquote>';
+      otp = '<blockquote' + showdown.helper._populateAttributes(attributes) + '>\n' +  bq + '\n</blockquote>';
     }
 
     let beforeHashEvent = new showdown.helper.Event('makehtml.blockQuotes.onHash', otp);

src/subParsers/makehtml/codeBlocks.js

@@ -65,24 +65,8 @@ showdown.subParser('makehtml.codeBlocks', function (text, options, globals) {
 
       otp = '<pre><code>';
       if (!showdown.helper.isUndefined(attributes)) {
-        otp = '<pre';
-        if (!showdown.helper.isUndefined(attributes.pre)) {
-          for (let preAttr in attributes.pre) {
-            if (attributes.hasOwnProperty(preAttr)) {
-              otp += ' ' + preAttr + '=' + attributes[preAttr];
-            }
-          }
-        }
-
-        otp += '><code';
-        if (!showdown.helper.isUndefined(attributes.code)) {
-          for (let codeAttr in attributes.code) {
-            if (attributes.hasOwnProperty(codeAttr)) {
-              otp += ' ' + codeAttr + '=' + attributes[codeAttr];
-            }
-          }
-        }
-        otp += '>';
+        otp = '<pre' + showdown.helper._populateAttributes(attributes.pre) + '>';
+        otp += '<code' + showdown.helper._populateAttributes(attributes.code) + '>';
       }
       if (options.omitExtraWLInCodeBlocks) {
         end = '';

src/subParsers/makehtml/codeSpans.js

@@ -26,23 +26,69 @@
 showdown.subParser('makehtml.codeSpans', function (text, options, globals) {
   'use strict';
 
-  text = globals.converter._dispatch('makehtml.codeSpans.before', text, options, globals).getText();
+  let startEvent = new showdown.helper.Event('makehtml.codeSpans.onStart', text);
+  startEvent
+    .setOutput(text)
+    ._setGlobals(globals)
+    ._setOptions(options);
 
-  if (typeof (text) === 'undefined') {
+  startEvent = globals.converter.dispatch(startEvent);
+
+  text = startEvent.output;
+
+  if (showdown.helper.isUndefined((text))) {
     text = '';
   }
-  text = text.replace(/(^|[^\\])(`+)([^\r]*?[^`])\2(?!`)/gm,
-    function (wholeMatch, m1, m2, m3) {
-      var c = m3;
+
+  let pattern = /(^|[^\\])(`+)([^\r]*?[^`])\2(?!`)/gm;
+
+  text = text.replace(pattern,
+    function (wholeMatch, m1, m2, c) {
+      let otp,
+          attributes = {};
+
       c = c.replace(/^([ \t]*)/g, '');	// leading whitespace
       c = c.replace(/[ \t]*$/g, '');	// trailing whitespace
-      c = showdown.subParser('makehtml.encodeCode')(c, options, globals);
-      c = m1 + '<code>' + c + '</code>';
-      c = showdown.subParser('makehtml.hashHTMLSpans')(c, options, globals);
-      return c;
+
+      let captureStartEvent = new showdown.helper.Event('makehtml.codeSpans.onCapture', c);
+      captureStartEvent
+        .setOutput(null)
+        ._setGlobals(globals)
+        ._setOptions(options)
+        .setRegexp(pattern)
+        .setMatches({
+          code: c
+        })
+        .setAttributes({});
+      captureStartEvent = globals.converter.dispatch(captureStartEvent);
+
+      // if something was passed as output, it takes precedence
+      // and will be used as output
+      if (captureStartEvent.output && captureStartEvent.output !== '') {
+        otp = m1 + captureStartEvent.output;
+      } else {
+        c = captureStartEvent.matches.code;
+        c = showdown.subParser('makehtml.encodeCode')(c, options, globals);
+        otp = m1 + '<code' + showdown.helper._populateAttributes(attributes) + '>' +  c + '</code>';
+      }
+
+      let beforeHashEvent = new showdown.helper.Event('makehtml.codeSpans.onHash', otp);
+      beforeHashEvent
+        .setOutput(otp)
+        ._setGlobals(globals)
+        ._setOptions(options);
+
+      beforeHashEvent = globals.converter.dispatch(beforeHashEvent);
+      otp = beforeHashEvent.output;
+      return showdown.subParser('makehtml.hashHTMLSpans')(otp, options, globals);
     }
   );
 
-  text = globals.converter._dispatch('makehtml.codeSpans.after', text, options, globals).getText();
-  return text;
+  let afterEvent = new showdown.helper.Event('makehtml.codeSpans.onEnd', text);
+  afterEvent
+    .setOutput(text)
+    ._setGlobals(globals)
+    ._setOptions(options);
+
+  return afterEvent.output;
 });