Fix breaking out of doctypes

Author: wooorm

lib/doctype.js

@@ -1,5 +1,9 @@
 'use strict'
 
+var xtend = require('xtend')
+var ccount = require('ccount')
+var entities = require('stringify-entities')
+
 module.exports = serializeDoctype
 
 var docLower = 'doctype'
@@ -17,20 +21,30 @@ function serializeDoctype(ctx, node) {
     val.push(sep, name)
 
     if (pub !== null && pub !== undefined) {
-      val.push(' public', sep, smart(pub))
+      val.push(' public', sep, quote(ctx, pub))
     } else if (sys !== null && sys !== undefined) {
       val.push(' system')
     }
 
     if (sys !== null && sys !== undefined) {
-      val.push(sep, smart(sys))
+      val.push(sep, quote(ctx, sys))
     }
   }
 
   return val.join('') + '>'
 }
 
-function smart(value) {
-  var quote = value.indexOf('"') === -1 ? '"' : "'"
-  return quote + value + quote
+function quote(ctx, value) {
+  var primary = ctx.quote
+  var secondary = ctx.alternative
+  var val = String(value)
+  var quote =
+    ccount(val, primary) > ccount(val, secondary) ? secondary : primary
+
+  return (
+    quote +
+    // Prevent breaking out of doctype.
+    entities(val, xtend(ctx.entities, {subset: ['<', '&', quote]})) +
+    quote
+  )
 }

lib/element.js

@@ -197,6 +197,7 @@ function serializeAttributeValue(ctx, key, value, info) {
   var options = ctx.entities
   var quote = ctx.quote
   var alternative = ctx.alternative
+  var smart = ctx.smart
   var unquoted
   var subset
 
@@ -225,7 +226,7 @@ function serializeAttributeValue(ctx, key, value, info) {
     // If `value` contains entities when unquoted…
     if (!ctx.unquoted || unquoted !== value) {
       // If the alternative is less common than `quote`, switch.
-      if (alternative && ccount(value, quote) > ccount(value, alternative)) {
+      if (smart && ccount(value, quote) > ccount(value, alternative)) {
         quote = alternative
       }
 

lib/index.js

@@ -47,7 +47,8 @@ function toHtml(node, options) {
       schema: settings.space === 'svg' ? svg : html,
       omit: settings.omitOptionalTags && omission,
       quote: quote,
-      alternative: smart ? alternative : null,
+      alternative: alternative,
+      smart: smart,
       unquoted: Boolean(settings.preferUnquoted),
       tight: settings.tightAttributes,
       upperDoctype: Boolean(settings.upperDoctype),