Bug 705072 - Limit HTML support in XHR to responseType == "document" to avoid changing the behavior for legacy users. r=smaug.

content/base/src/nsXMLHttpRequest.cpp

@@ -884,7 +884,7 @@ NS_IMETHODIMP nsXMLHttpRequest::GetResponseText(nsAString& aResponseText)
   // We only decode text lazily if we're also parsing to a doc.
   // Also, if we've decoded all current data already, then no need to decode
   // more.
-  if (IsWaitingForHTMLCharset() || !mResponseXML ||
+  if (!mResponseXML ||
       mResponseBodyDecodedPos == mResponseBody.Length()) {
     aResponseText = mResponseText;
     return NS_OK;
@@ -1473,16 +1473,6 @@ nsXMLHttpRequest::IsSystemXHR()
   return !!nsContentUtils::IsSystemPrincipal(mPrincipal);
 }
 
-bool
-nsXMLHttpRequest::IsWaitingForHTMLCharset()
-{
-  if (!mIsHtml || !mResponseXML) {
-    return false;
-  }
-  nsCOMPtr<nsIDocument> doc = do_QueryInterface(mResponseXML);
-  return doc->GetDocumentCharacterSetSource() < kCharsetFromDocTypeDefault;
-}
-
 nsresult
 nsXMLHttpRequest::CheckChannelForCrossSiteRequest(nsIChannel* aChannel)
 {
@@ -1928,7 +1918,13 @@ nsXMLHttpRequest::OnStartRequest(nsIRequest *request, nsISupports *ctxt)
     nsCAutoString type;
     channel->GetContentType(type);
 
-    if (type.EqualsLiteral("text/html")) {
+    if ((mResponseType == XML_HTTP_RESPONSE_TYPE_DOCUMENT) &&
+        type.EqualsLiteral("text/html")) {
+      // HTML parsing is only supported for responseType == "document" to
+      // avoid running the parser and, worse, populating responseXML for
+      // legacy users of XHR who use responseType == "" for retrieving the
+      // responseText of text/html resources. This legacy case is so common
+      // that it's not useful to emit a warning about it.
       if (!(mState & XML_HTTP_REQUEST_ASYNC)) {
         // We don't make cool new features available in the bad synchronous
         // mode. The synchronous mode is for legacy only.
@@ -3138,13 +3134,11 @@ nsXMLHttpRequest::MaybeDispatchProgressEvents(bool aFinalProgress)
       mLoadTotal = mLoadTransferred;
       mLoadLengthComputable = true;
     }
-    if (aFinalProgress || !IsWaitingForHTMLCharset()) {
-      mInLoadProgressEvent = true;
-      DispatchProgressEvent(this, NS_LITERAL_STRING(PROGRESS_STR),
-                            true, mLoadLengthComputable, mLoadTransferred,
-                            mLoadTotal, mLoadTransferred, mLoadTotal);
-      mInLoadProgressEvent = false;
-    }
+    mInLoadProgressEvent = true;
+    DispatchProgressEvent(this, NS_LITERAL_STRING(PROGRESS_STR),
+                          true, mLoadLengthComputable, mLoadTransferred,
+                          mLoadTotal, mLoadTransferred, mLoadTotal);
+    mInLoadProgressEvent = false;
     if (mResponseType == XML_HTTP_RESPONSE_TYPE_CHUNKED_TEXT ||
         mResponseType == XML_HTTP_RESPONSE_TYPE_CHUNKED_ARRAYBUFFER) {
       mResponseBody.Truncate();

content/base/src/nsXMLHttpRequest.h

@@ -236,8 +236,6 @@ protected:
 
   bool IsSystemXHR();
 
-  bool IsWaitingForHTMLCharset();
-
   void ChangeStateToDone();
 
   /**

content/base/test/Makefile.in

@@ -510,7 +510,6 @@ _TEST_FILES2 = \
 		file_html_in_xhr2.html \
 		file_html_in_xhr3.html \
 		file_html_in_xhr.sjs \
-		file_html_in_xhr_slow.sjs \
 		test_bug664916.html \
 		test_bug666604.html \
 		test_bug675121.html \

content/base/test/file_html_in_xhr_slow.sjs

@@ -1,24 +0,0 @@
-var timer;
-
-function handleRequest(request, response)
-{
-  var converter = Components.classes["@mozilla.org/intl/scriptableunicodeconverter"]
-    .createInstance(Components.interfaces.nsIScriptableUnicodeConverter);
-  converter.charset = "windows-1251";
-  var stream = converter.convertToInputStream("\u042E");
-  var out = response.bodyOutputStream;
-  response.setHeader("Cache-Control", "no-cache", false);
-  response.setHeader("Content-Type", "text/html", false);
-  out.writeFrom(stream, 1);
-  var firstPart = "<meta charset='windows";
-  out.write(firstPart, firstPart.length);
-  out.flush();
-  response.processAsync();
-  timer = Components.classes["@mozilla.org/timer;1"]
-    .createInstance(Components.interfaces.nsITimer);
-  timer.initWithCallback(function() {
-      response.write("-1251'>");      
-      response.finish();
-    }, 500, Components.interfaces.nsITimer.TYPE_ONE_SHOT);
-}
-

content/base/test/test_html_in_xhr.html

@@ -29,7 +29,12 @@ function runTest() {
       ok(this.responseXML, "Should have gotten responseXML");
       is(this.responseXML.characterSet, "windows-1251", "Wrong character encoding");
       is(this.responseXML.documentElement.firstChild.data, " \u042E ", "Decoded using the wrong encoding.");
-      is(this.responseText.indexOf("\u042E"), 27, "Bad responseText");
+      try {
+        this.responseText;
+        ok(false, "responseText access should have thrown.");
+      } catch (e) {
+        is(e.code, 11, "Should have thrown INVALID_STATE_ERR.");
+      }
       is(this.responseXML.getElementsByTagName("div").length, 1, "There should be one div.");
       ok(!this.responseXML.documentElement.hasAttribute("data-fail"), "Should not have a data-fail attribute.");
       var scripts = this.responseXML.getElementsByTagName("script");
@@ -44,27 +49,21 @@ function runTest() {
     }
   }
   xhr.open("GET", "file_html_in_xhr.html", true);
+  xhr.responseType = "document";
   xhr.send();
 }
 
 function continueAfterReport() {
-  ok(!document.documentElement.hasAttribute("data-fail"), "Should not have a data-fail attribute on mochitest doc.");  
   xhr = new XMLHttpRequest();
-  xhr.onprogress = function() {
-    ok(this.responseText, "Got falsy responseText");
-    if (this.responseText) {
-      ok(this.responseText.length, "Got zero-length responseText");
-      if (this.responseText.length) {
-        is(this.responseText.charCodeAt(0), 0x042E, "Wrong character encoding for slow text");
-      }
-    }
-  }
   xhr.onreadystatechange = function() {
     if (this.readyState == 4) {
+      is(this.responseText.indexOf("\u042E"), -1, "Honored meta in default mode.");
+      is(this.responseText.indexOf("\uFFFD"), 29, "Honored meta in default mode 2.");
+      is(this.responseXML, null, "responseXML should be null for HTML in the default mode");
       testNonParsingText();
     }
   }
-  xhr.open("GET", "file_html_in_xhr_slow.sjs");
+  xhr.open("GET", "file_html_in_xhr2.html");
   xhr.send();   
 }