From 0e548a83c0856d537ecb1e1bfb6ef9d8770934e9 Mon Sep 17 00:00:00 2001
From: "Maxim.Mossienko" <Maxim.Mossienko@jetbrains.com>
Date: Thu, 12 Dec 2013 22:33:39 +0100
Subject: [PATCH] - detect proper encoding for html5's <meta
 charset="charsetname"> - [performance fix] avoid (light) parsing of html
 content if there is no charset\s*= pattern inside the string

---
 .../src/com/intellij/xml/util/HtmlUtil.java   | 39 +++++++++++++++----
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/xml/xml-psi-impl/src/com/intellij/xml/util/HtmlUtil.java b/xml/xml-psi-impl/src/com/intellij/xml/util/HtmlUtil.java
index ff1fedcc8542..85410a764d94 100644
--- a/xml/xml-psi-impl/src/com/intellij/xml/util/HtmlUtil.java
+++ b/xml/xml-psi-impl/src/com/intellij/xml/util/HtmlUtil.java
@@ -27,6 +27,7 @@ import com.intellij.lang.xhtml.XHTMLLanguage;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.fileTypes.FileType;
 import com.intellij.openapi.util.Ref;
+import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vfs.CharsetToolkit;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.profile.codeInspection.InspectionProjectProfileManager;
@@ -65,7 +66,8 @@ public class HtmlUtil {
   private static final Logger LOG = Logger.getInstance("#com.intellij.xml.util.HtmlUtil");
 
   @NonNls private static final String JSFC = "jsfc";
-  @NonNls private static final String CHARSET_PREFIX = "charset=";
+  @NonNls private static final String CHARSET = "charset";
+  @NonNls private static final String CHARSET_PREFIX = CHARSET+"=";
   @NonNls private static final String HTML5_DATA_ATTR_PREFIX = "data-";
 
   public static final String[] CONTENT_TYPES =
@@ -444,11 +446,23 @@ public class HtmlUtil {
   }
 
   public static Charset detectCharsetFromMetaHttpEquiv(@NotNull String content) {
+    // check for <meta http-equiv="charset=CharsetName" > or <meta charset="CharsetName"> and return Charset
+    // because we will lightly parse and explicit charset isn't used very often do quick check for applicability
+    int charPrefix = content.indexOf(CHARSET);
+    do {
+      if (charPrefix == -1) return null;
+      int charsetPrefixEnd = charPrefix + CHARSET.length();
+      while (charsetPrefixEnd < content.length() && Character.isWhitespace(content.charAt(charsetPrefixEnd))) ++charsetPrefixEnd;
+      if (charsetPrefixEnd < content.length() && content.charAt(charsetPrefixEnd) == '=') break;
+      charPrefix = content.indexOf(CHARSET, charsetPrefixEnd);
+    } while(true);
+
     final Ref<String> charsetNameRef = new Ref<String>();
     try {
       new HtmlBuilderDriver(content).build(new XmlBuilder() {
         @NonNls final Set<String> inTag = new THashSet<String>();
         boolean metHttpEquiv = false;
+        boolean metHttml5Charset = false;
 
         @Override
         public void doctype(@Nullable final CharSequence publicId,
@@ -473,13 +487,18 @@ public class HtmlUtil {
         @Override
         public void endTag(final CharSequence localName, final String namespace, final int startoffset, final int endoffset) {
           @NonNls final String name = localName.toString().toLowerCase();
-          if ("meta".equals(name) && metHttpEquiv && contentAttributeValue != null) {
-            int start = contentAttributeValue.indexOf(CHARSET_PREFIX);
-            if (start == -1) return;
-            start += CHARSET_PREFIX.length();
-            int end = contentAttributeValue.indexOf(';', start);
-            if (end == -1) end = contentAttributeValue.length();
-            String charsetName = contentAttributeValue.substring(start, end);
+          if ("meta".equals(name) && (metHttpEquiv || metHttml5Charset) && contentAttributeValue != null) {
+            String charsetName = null;
+            if (metHttpEquiv) {
+              int start = contentAttributeValue.indexOf(CHARSET_PREFIX);
+              if (start == -1) return;
+              start += CHARSET_PREFIX.length();
+              int end = contentAttributeValue.indexOf(';', start);
+              if (end == -1) end = contentAttributeValue.length();
+              charsetName = contentAttributeValue.substring(start, end);
+            } else /*if (metHttml5Charset) */ {
+              charsetName = StringUtil.stripQuotesAroundValue(contentAttributeValue);
+            }
             charsetNameRef.set(charsetName);
             terminate();
           }
@@ -488,6 +507,7 @@ public class HtmlUtil {
           }
           inTag.remove(name);
           metHttpEquiv = false;
+          metHttml5Charset = false;
           contentAttributeValue = null;
         }
 
@@ -500,6 +520,9 @@ public class HtmlUtil {
             @NonNls String value = v.toString().toLowerCase();
             if (name.equals("http-equiv")) {
               metHttpEquiv |= value.equals("content-type");
+            } else if (name.equals(CHARSET)) {
+              metHttml5Charset = true;
+              contentAttributeValue = value;
             }
             if (name.equals("content")) {
               contentAttributeValue = value;