diff --git a/editor/libeditor/base/ChangeCSSInlineStyleTxn.cpp b/editor/libeditor/base/ChangeCSSInlineStyleTxn.cpp
index e58c5b0a1a6..b11bcd2b4d6 100644
--- a/editor/libeditor/base/ChangeCSSInlineStyleTxn.cpp
+++ b/editor/libeditor/base/ChangeCSSInlineStyleTxn.cpp
@@ -92,8 +92,9 @@ ChangeCSSInlineStyleTxn::ValueIncludes(const nsAReadableString &aValueList, cons
         }
       }
       else {
-        if (nsDependentString(value).Equals(nsDependentString(start),
-                                            nsCaseInsensitiveStringComparator())) {
+        if (!Compare(nsDependentString(value),
+                     nsDependentString(start),
+                     nsCaseInsensitiveStringComparator())) {
           result = PR_TRUE;
           break;
         }
@@ -369,9 +370,8 @@ ChangeCSSInlineStyleTxn::AcceptsMoreThanOneValue(nsIAtom *aCSSProperty)
 NS_IMETHODIMP
 ChangeCSSInlineStyleTxn::AddValueToMultivalueProperty(nsAWritableString & aValues, const nsAReadableString & aNewValue)
 {
-  if (aValues.IsEmpty()
-      || aValues.Equals(NS_LITERAL_STRING("none"),
-                        nsCaseInsensitiveStringComparator())) {
+  if (!aValues.Length()
+      || !Compare(aValues, NS_LITERAL_STRING("none"), nsCaseInsensitiveStringComparator())) {
     // the list of values is empty of the value is 'none'
     aValues.Assign(aNewValue);
   }
diff --git a/editor/libeditor/html/nsHTMLCSSUtils.cpp b/editor/libeditor/html/nsHTMLCSSUtils.cpp
index a78614f7628..3e6632db933 100644
--- a/editor/libeditor/html/nsHTMLCSSUtils.cpp
+++ b/editor/libeditor/html/nsHTMLCSSUtils.cpp
@@ -1179,8 +1179,7 @@ nsHTMLCSSUtils::IsCSSEquivalentToHTMLInlineStyleSet(nsIDOMNode * aNode,
       if (!htmlValueString.Equals(NS_LITERAL_STRING(""))) {
         nsAutoString leftHTMLValue;
         htmlValueString.Left(leftHTMLValue, 5);
-        aIsSet = leftHTMLValue.Equals(leftCSSValue,
-                                      nsCaseInsensitiveStringComparator());
+        aIsSet = PRBool(!Compare(leftHTMLValue, leftCSSValue, nsCaseInsensitiveStringComparator()));
       }
       else {
         aIsSet = (leftCSSValue.Equals(NS_LITERAL_STRING("times")) ||
@@ -1203,8 +1202,7 @@ nsHTMLCSSUtils::IsCSSEquivalentToHTMLInlineStyleSet(nsIDOMNode * aNode,
     }
 
     if (!htmlValueString.Equals(NS_LITERAL_STRING(""))) {
-      if (htmlValueString.Equals(valueString,
-                                 nsCaseInsensitiveStringComparator())) {
+      if (!Compare(htmlValueString, valueString, nsCaseInsensitiveStringComparator())) {
         aIsSet = PR_TRUE;
       }
     }
diff --git a/editor/libeditor/html/nsHTMLEditRules.cpp b/editor/libeditor/html/nsHTMLEditRules.cpp
index 253c1434543..427a924b402 100644
--- a/editor/libeditor/html/nsHTMLEditRules.cpp
+++ b/editor/libeditor/html/nsHTMLEditRules.cpp
@@ -2492,7 +2492,7 @@ nsHTMLEditRules::WillMakeList(nsISelection *aSelection,
   nsAutoString itemType;
   if (aItemType) 
     itemType = *aItemType;
-  else if (aListType->Equals(NS_LITERAL_STRING("dl"),nsCaseInsensitiveStringComparator()))
+  else if (!Compare(*aListType,NS_LITERAL_STRING("dl"),nsCaseInsensitiveStringComparator()))
     itemType.Assign(NS_LITERAL_STRING("dd"));
   else
     itemType.Assign(NS_LITERAL_STRING("li"));
@@ -6148,7 +6148,7 @@ nsHTMLEditRules::ApplyBlockStyle(nsISupportsArray *arrayOfNodes, const nsAReadab
     else if (IsInlineNode(curNode))
     {
       // if curNode is a non editable, drop it if we are going to <pre>
-      if (tString.Equals(NS_LITERAL_STRING("pre"),nsCaseInsensitiveStringComparator()) 
+      if (!Compare(tString,NS_LITERAL_STRING("pre"),nsCaseInsensitiveStringComparator()) 
         && (!mHTMLEditor->IsEditable(curNode)))
         continue; // do nothing to this block
       
diff --git a/editor/libeditor/html/nsHTMLEditor.cpp b/editor/libeditor/html/nsHTMLEditor.cpp
index 5f04e3a9b2e..f4ab17890e3 100644
--- a/editor/libeditor/html/nsHTMLEditor.cpp
+++ b/editor/libeditor/html/nsHTMLEditor.cpp
@@ -2461,7 +2461,7 @@ nsHTMLEditor::RemoveList(const nsAReadableString& aListType)
   if (!selection) return NS_ERROR_NULL_POINTER;
 
   nsTextRulesInfo ruleInfo(nsTextEditRules::kRemoveList);
-  if (aListType.Equals(NS_LITERAL_STRING("ol"),nsCaseInsensitiveStringComparator()))
+  if (!Compare(aListType,NS_LITERAL_STRING("ol"),nsCaseInsensitiveStringComparator()))
     ruleInfo.bOrdered = PR_TRUE;
   else  ruleInfo.bOrdered = PR_FALSE;
   res = mRules->WillDoAction(selection, &ruleInfo, &cancel, &handled);
@@ -2584,7 +2584,7 @@ nsHTMLEditor::Indent(const nsAReadableString& aIndent)
   PRBool cancel, handled;
   PRInt32 theAction = nsTextEditRules::kIndent;
   PRInt32 opID = kOpIndent;
-  if (aIndent.Equals(NS_LITERAL_STRING("outdent"),nsCaseInsensitiveStringComparator()))
+  if (!Compare(aIndent,NS_LITERAL_STRING("outdent"),nsCaseInsensitiveStringComparator()))
   {
     theAction = nsTextEditRules::kOutdent;
     opID = kOpOutdent;
@@ -3571,8 +3571,7 @@ nsHTMLEditor::GetEmbeddedObjects(nsISupportsArray** aNodeList)
           {
             nsAutoString href;
             if (NS_SUCCEEDED(anchor->GetHref(href)))
-              if (Substring(href, 0, 5).Equals(NS_LITERAL_STRING("file:"),
-                                               nsCaseInsensitiveStringComparator()))
+              if (Compare(Substring(href, 0, 5), NS_LITERAL_STRING("file:"), nsCaseInsensitiveStringComparator()) == 0)
                 (*aNodeList)->AppendElement(node);
           }
         }
@@ -3864,20 +3863,20 @@ PRBool
 nsHTMLEditor::TagCanContainTag(const nsAReadableString& aParentTag, const nsAReadableString& aChildTag)  
 {
   // COtherDTD gives some unwanted results.  We override them here.
-  if (aParentTag.Equals(NS_LITERAL_STRING("ol"),nsCaseInsensitiveStringComparator()) ||
-      aParentTag.Equals(NS_LITERAL_STRING("ul"),nsCaseInsensitiveStringComparator()))
+  if (!Compare(aParentTag,NS_LITERAL_STRING("ol"),nsCaseInsensitiveStringComparator()) ||
+    !Compare(aParentTag,NS_LITERAL_STRING("ul"),nsCaseInsensitiveStringComparator()))
   {
     // if parent is a list and tag is also a list, say "yes".
     // This is because the editor does sublists illegally for now. 
-      if (aChildTag.Equals(NS_LITERAL_STRING("ol"),nsCaseInsensitiveStringComparator()) ||
-          aChildTag.Equals(NS_LITERAL_STRING("ul"),nsCaseInsensitiveStringComparator()))
+      if (!Compare(aChildTag,NS_LITERAL_STRING("ol"),nsCaseInsensitiveStringComparator()) ||
+        !Compare(aChildTag,NS_LITERAL_STRING("ul"),nsCaseInsensitiveStringComparator()))
       return PR_TRUE;
   }
 
-  if (aParentTag.Equals(NS_LITERAL_STRING("li"),nsCaseInsensitiveStringComparator()))
+  if (!Compare(aParentTag,NS_LITERAL_STRING("li"),nsCaseInsensitiveStringComparator()))
   {
     // list items cant contain list items
-    if (aChildTag.Equals(NS_LITERAL_STRING("li"),nsCaseInsensitiveStringComparator()))
+    if (!Compare(aChildTag,NS_LITERAL_STRING("li"),nsCaseInsensitiveStringComparator()))
       return PR_FALSE;
   }
 
diff --git a/editor/libeditor/html/nsHTMLEditorStyle.cpp b/editor/libeditor/html/nsHTMLEditorStyle.cpp
index 0ea49f6d656..82d5a4d7200 100644
--- a/editor/libeditor/html/nsHTMLEditorStyle.cpp
+++ b/editor/libeditor/html/nsHTMLEditorStyle.cpp
@@ -715,7 +715,7 @@ nsresult nsHTMLEditor::RemoveStyleInside(nsIDOMNode *aNode,
   }  
   if ( aProperty == nsIEditProperty::font &&    // or node is big or small and we are setting font size
        (NodeIsType(aNode, nsIEditProperty::big) || NodeIsType(aNode, nsIEditProperty::small)) &&
-       aAttribute->Equals(NS_LITERAL_STRING("size"),nsCaseInsensitiveStringComparator()))       
+       !Compare(*aAttribute,NS_LITERAL_STRING("size"),nsCaseInsensitiveStringComparator()))       
   {
     res = RemoveContainer(aNode);  // if we are setting font size, remove any nested bigs and smalls
   }
@@ -741,10 +741,10 @@ PRBool nsHTMLEditor::IsOnlyAttribute(nsIDOMNode *aNode,
     if (!attrName) continue;  // ooops
     attrName->ToString(attrString);
     // if it's the attribute we know about, keep looking
-    if (attrString.Equals(*aAttribute,nsCaseInsensitiveStringComparator())) continue;
+    if (!Compare(attrString,*aAttribute,nsCaseInsensitiveStringComparator())) continue;
     // if it's a special _moz... attribute, keep looking
     attrString.Left(tmp,4);
-    if (tmp.Equals(NS_LITERAL_STRING("_moz"),nsCaseInsensitiveStringComparator())) continue;
+    if (!Compare(tmp,NS_LITERAL_STRING("_moz"),nsCaseInsensitiveStringComparator())) continue;
     // otherwise, it's another attribute, so return false
     return PR_FALSE;
   }
@@ -798,7 +798,7 @@ PRBool nsHTMLEditor::HasAttrVal(nsIDOMNode *aNode,
   attNode->GetValue(attrVal);
   
   // do values match?
-  if (attrVal.Equals(*aValue,nsCaseInsensitiveStringComparator())) return PR_TRUE;
+  if (!Compare(attrVal,*aValue,nsCaseInsensitiveStringComparator())) return PR_TRUE;
   return PR_FALSE;
 }
 
diff --git a/editor/libeditor/text/nsAOLCiter.cpp b/editor/libeditor/text/nsAOLCiter.cpp
index 259a50dcbe0..a00a98f26c9 100644
--- a/editor/libeditor/text/nsAOLCiter.cpp
+++ b/editor/libeditor/text/nsAOLCiter.cpp
@@ -107,7 +107,7 @@ nsAOLCiter::StripCites(const nsAReadableString& aInString, nsAWritableString& aO
   nsReadingIterator <PRUnichar> iter,enditer;
   aInString.BeginReading(iter);
   aInString.EndReading(enditer);
-  if (Substring(aInString,0,2).Equals(NS_LITERAL_STRING(">>")))
+  if (!Compare(Substring(aInString,0,2),NS_LITERAL_STRING(">>")))
   {
     iter.advance(2);
     while (nsCRT::IsAsciiSpace(*iter))
diff --git a/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp b/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp
index 4d27844a596..55764eacfb4 100644
--- a/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp
+++ b/embedding/browser/webBrowser/nsDocShellTreeOwner.cpp
@@ -1466,27 +1466,27 @@ ChromeContextMenuListener :: ContextMenu ( nsIDOMEvent* aMouseEvent )
       element->GetTagName(tag);
 
       // Test what kind of element we're dealing with here
-      if (tag.Equals(NS_LITERAL_STRING("img"), nsCaseInsensitiveStringComparator()))
+      if (!Compare(tag, NS_LITERAL_STRING("img"), nsCaseInsensitiveStringComparator()))
       {
         flags |= nsIContextMenuListener::CONTEXT_IMAGE;
         targetDOMnode = node;
         // if we see an image, keep searching for a possible anchor
       }
-      else if (tag.Equals(NS_LITERAL_STRING("input"), nsCaseInsensitiveStringComparator()))
+      else if (!Compare(tag, NS_LITERAL_STRING("input"), nsCaseInsensitiveStringComparator()))
       {
         // INPUT element - button, combo, checkbox, text etc.
         flags |= nsIContextMenuListener::CONTEXT_INPUT;
         targetDOMnode = node;
         break; // exit do-while
       }
-      else if (tag.Equals(NS_LITERAL_STRING("textarea"), nsCaseInsensitiveStringComparator()))
+      else if (!Compare(tag, NS_LITERAL_STRING("textarea"), nsCaseInsensitiveStringComparator()))
       {
         // text area
         flags |= nsIContextMenuListener::CONTEXT_TEXT;
         targetDOMnode = node;
         break; // exit do-while
       }
-      else if (tag.Equals(NS_LITERAL_STRING("html"), nsCaseInsensitiveStringComparator()))
+      else if (!Compare(tag, NS_LITERAL_STRING("html"), nsCaseInsensitiveStringComparator()))
       {
         // only care about this if no other context was found.
         if (!flags) {
@@ -1508,7 +1508,8 @@ ChromeContextMenuListener :: ContextMenu ( nsIDOMEvent* aMouseEvent )
       if (attributes)
       {
         nsCOMPtr<nsIDOMNode> hrefNode;
-        attributes->GetNamedItem(NS_LITERAL_STRING("href"), getter_AddRefs(hrefNode));
+        nsAutoString href(NS_LITERAL_STRING("href"));
+        attributes->GetNamedItem(href, getter_AddRefs(hrefNode));
         if (hrefNode)
         {
           flags |= nsIContextMenuListener::CONTEXT_LINK;
diff --git a/extensions/wallet/src/nsWalletService.cpp b/extensions/wallet/src/nsWalletService.cpp
index 2c67ab05565..29efe6b3162 100644
--- a/extensions/wallet/src/nsWalletService.cpp
+++ b/extensions/wallet/src/nsWalletService.cpp
@@ -429,7 +429,7 @@ nsWalletlibService::OnStateChange(nsIWebProgress* aWebProgress,
                         nsAutoString type;
                         rv = inputElement->GetType(type);
                         if (NS_SUCCEEDED(rv)) {
-                          if (type.Equals(NS_LITERAL_STRING("password"), nsCaseInsensitiveStringComparator())) {
+                          if (Compare(type, NS_LITERAL_STRING("password"), nsCaseInsensitiveStringComparator()) == 0) {
                             passwordCount++;
                           }
                         }
@@ -449,11 +449,8 @@ nsWalletlibService::OnStateChange(nsIWebProgress* aWebProgress,
                         nsAutoString type;
                         rv = inputElement->GetType(type);
                         if (NS_SUCCEEDED(rv)) {
-                          if (type.IsEmpty() ||
-                              type.Equals(NS_LITERAL_STRING("text"),
-                                          nsCaseInsensitiveStringComparator()) ||
-                              type.Equals(NS_LITERAL_STRING("password"),
-                                          nsCaseInsensitiveStringComparator())) {
+                          if ((type.IsEmpty()) || (Compare(type, NS_LITERAL_STRING("text"), nsCaseInsensitiveStringComparator()) == 0) ||
+                            (Compare(type, NS_LITERAL_STRING("password"), nsCaseInsensitiveStringComparator()) == 0)) {
                             nsAutoString field;
                             rv = inputElement->GetName(field);
                             if (NS_SUCCEEDED(rv)) {
diff --git a/extensions/wallet/src/wallet.cpp b/extensions/wallet/src/wallet.cpp
index 72200363696..0a9b646387d 100644
--- a/extensions/wallet/src/wallet.cpp
+++ b/extensions/wallet/src/wallet.cpp
@@ -1960,16 +1960,14 @@ wallet_StepForwardOrBack
       if (goForward) {
         if (NS_SUCCEEDED(result) &&
             (type.IsEmpty() ||
-             type.Equals(NS_LITERAL_STRING("text"), 
-                         nsCaseInsensitiveStringComparator()))) {
+             (Compare(type, NS_LITERAL_STRING("text"), 
+                      nsCaseInsensitiveStringComparator()) == 0))) {
           /* at <input> element and it's type is either "text" or is missing ("text" by default) */
           atInputOrSelect = PR_TRUE;
           return;
         }
       } else {
-        if (NS_SUCCEEDED(result) &&
-            !type.Equals(NS_LITERAL_STRING("hidden"),
-                         nsCaseInsensitiveStringComparator())) {
+        if (NS_SUCCEEDED(result) && (Compare(type, NS_LITERAL_STRING("hidden"), nsCaseInsensitiveStringComparator()) != 0)) {
           /* at <input> element and it's type is not "hidden" */
           atInputOrSelect = PR_TRUE;
           return;
@@ -2404,10 +2402,7 @@ wallet_GetPrefills(
   if ((NS_SUCCEEDED(result)) && (nsnull != inputElement)) {
     nsAutoString type;
     result = inputElement->GetType(type);
-    if (NS_SUCCEEDED(result) &&
-        (type.IsEmpty() ||
-         type.Equals(NS_LITERAL_STRING("text"),
-                     nsCaseInsensitiveStringComparator()))) {
+    if ((NS_SUCCEEDED(result)) && ((type.IsEmpty()) || (Compare(type, NS_LITERAL_STRING("text"), nsCaseInsensitiveStringComparator()) == 0))) {
       nsAutoString field;
       result = inputElement->GetName(field);
       if (NS_SUCCEEDED(result)) {
@@ -3641,10 +3636,8 @@ wallet_CaptureInputElement(nsIDOMNode* elementNode, nsIDocument* doc) {
     /* it's an input element */
     nsAutoString type;
     result = inputElement->GetType(type);
-    if (NS_SUCCEEDED(result) &&
-        (type.IsEmpty() ||
-         type.Equals(NS_LITERAL_STRING("text"),
-                     nsCaseInsensitiveStringComparator()))) {
+    if ((NS_SUCCEEDED(result)) &&
+        (type.IsEmpty() || (Compare(type, NS_LITERAL_STRING("text"), nsCaseInsensitiveStringComparator()) == 0))) {
       nsAutoString field;
       result = inputElement->GetName(field);
       if (NS_SUCCEEDED(result)) {
@@ -3999,8 +3992,8 @@ WLLT_OnSubmit(nsIContent* currentForm, nsIDOMWindowInternal* window) {
                 rv = inputElement->GetType(type);
                 if (NS_SUCCEEDED(rv)) {
 
-                  PRBool isText = (type.IsEmpty() || type.Equals(NS_LITERAL_STRING("text"), nsCaseInsensitiveStringComparator()));
-                  PRBool isPassword = type.Equals(NS_LITERAL_STRING("password"), nsCaseInsensitiveStringComparator());
+                  PRBool isText = (type.IsEmpty() || (Compare(type, NS_LITERAL_STRING("text"), nsCaseInsensitiveStringComparator())==0));
+                  PRBool isPassword = (Compare(type, NS_LITERAL_STRING("password"), nsCaseInsensitiveStringComparator())==0);
 
                   // don't save password if field was left blank
                   if (isPassword) {
diff --git a/htmlparser/src/CNavDTD.cpp b/htmlparser/src/CNavDTD.cpp
index e424a0e72bc..3c5474218f0 100644
--- a/htmlparser/src/CNavDTD.cpp
+++ b/htmlparser/src/CNavDTD.cpp
@@ -1013,12 +1013,12 @@ nsresult CNavDTD::DidHandleStartTag(nsIParserNode& aNode,eHTMLTags aChildTag){
         if(theCount) {
           PRInt32 theIndex=0;
           for(theIndex=0;theIndex<theCount;theIndex++){
-            const nsAString& theKey = aNode.GetKeyAt(theIndex);
-            if(theKey.Equals(NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
+            nsAutoString theKey(aNode.GetKeyAt(theIndex));
+            if(!Compare(theKey, NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
               const nsString& theName=aNode.GetValueAt(theIndex);
               theNamePtr=&theName;
             }
-            else if(theKey.Equals(NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
+            else if(!Compare(theKey, NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
               //store the named enity with the context...
               const nsString& theValue=aNode.GetValueAt(theIndex);
               theValuePtr=&theValue;
diff --git a/htmlparser/src/COtherDTD.cpp b/htmlparser/src/COtherDTD.cpp
index a2478a821c2..169aab02185 100644
--- a/htmlparser/src/COtherDTD.cpp
+++ b/htmlparser/src/COtherDTD.cpp
@@ -588,12 +588,12 @@ nsresult COtherDTD::DidHandleStartTag(nsIParserNode& aNode,eHTMLTags aChildTag){
         if(theCount) {
           PRInt32 theIndex=0;
           for(theIndex=0;theIndex<theCount;theIndex++){
-            const nsAString& theKey = aNode.GetKeyAt(theIndex);
-            if(theKey.Equals(NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
+            nsAutoString theKey(aNode.GetKeyAt(theIndex));
+            if(!Compare(theKey, NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
               const nsString& theName=aNode.GetValueAt(theIndex);
               theNamePtr=&theName;
             }
-            else if(theKey.Equals(NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
+            else if(!Compare(theKey, NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
               //store the named enity with the context...
               const nsString& theValue=aNode.GetValueAt(theIndex);
               theValuePtr=&theValue;
diff --git a/htmlparser/src/nsDTDUtils.cpp b/htmlparser/src/nsDTDUtils.cpp
index 1e13e5169af..e52d467fddf 100644
--- a/htmlparser/src/nsDTDUtils.cpp
+++ b/htmlparser/src/nsDTDUtils.cpp
@@ -842,10 +842,10 @@ PRInt32 nsDTDContext::IncrementCounter(eHTMLTags aTag,nsIParserNode& aNode,nsStr
   CAbacus::eNumFormat  theNumFormat=CAbacus::eDecimal;
 
   for(theIndex=0;theIndex<theCount;theIndex++){
-    const nsAString& theKey=aNode.GetKeyAt(theIndex);
+    nsAutoString theKey(aNode.GetKeyAt(theIndex));
     const nsString& theValue=aNode.GetValueAt(theIndex);
 
-    if(theKey.Equals(NS_LITERAL_STRING("name"), nsCaseInsensitiveStringComparator())){
+    if(!Compare(theKey, NS_LITERAL_STRING("name"), nsCaseInsensitiveStringComparator())){
       theEntity=GetEntity(theValue);
       if(!theEntity) {
         theEntity=RegisterEntity(theValue,theValue);
@@ -853,10 +853,10 @@ PRInt32 nsDTDContext::IncrementCounter(eHTMLTags aTag,nsIParserNode& aNode,nsStr
       }
       aTag=eHTMLTag_userdefined;
     }
-    else if(theKey.Equals(NS_LITERAL_STRING("noincr"), nsCaseInsensitiveStringComparator())){
+    else if(!Compare(theKey, NS_LITERAL_STRING("noincr"), nsCaseInsensitiveStringComparator())){
       theIncrValue=0;
     }
-    else if(theKey.Equals(NS_LITERAL_STRING("format"), nsCaseInsensitiveStringComparator())){
+    else if(!Compare(theKey, NS_LITERAL_STRING("format"), nsCaseInsensitiveStringComparator())){
       PRUnichar theChar=theValue.CharAt(0);
       if('"'==theChar)
         theChar=theValue.CharAt(1);
@@ -873,7 +873,7 @@ PRInt32 nsDTDContext::IncrementCounter(eHTMLTags aTag,nsIParserNode& aNode,nsStr
       }
       //determine numbering style
     }
-    else if(theKey.Equals(NS_LITERAL_STRING("value"), nsCaseInsensitiveStringComparator())){
+    else if(!Compare(theKey, NS_LITERAL_STRING("value"), nsCaseInsensitiveStringComparator())){
       PRInt32 err=0;
       theNewValue=theValue.ToInteger(&err);
       if(!err) {
diff --git a/htmlparser/src/nsHTMLContentSinkStream.cpp b/htmlparser/src/nsHTMLContentSinkStream.cpp
index 62fdfbc57b1..46768dec5fc 100644
--- a/htmlparser/src/nsHTMLContentSinkStream.cpp
+++ b/htmlparser/src/nsHTMLContentSinkStream.cpp
@@ -413,7 +413,7 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
   if(theCount) {
     int i=0;
     for(i=0;i<theCount;i++){
-      const nsAString& key = aNode.GetKeyAt(i);
+      nsAutoString key(aNode.GetKeyAt(i));
       
       // See if there's an attribute:
       // note that we copy here, because we're going to have to trim quotes.
@@ -423,7 +423,7 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
       value.Trim("\"", PR_TRUE, PR_TRUE);
 
       // Filter out any attribute starting with _moz
-      if (key.Equals(NS_LITERAL_STRING("_moz"), nsCaseInsensitiveStringComparator()))
+      if (!Compare(key, NS_LITERAL_STRING("_moz"), nsCaseInsensitiveStringComparator())
         continue;
 
       // 
@@ -437,8 +437,8 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
       // used by the editor.  Bug 16988.  Yuck.
       //
       if ((eHTMLTags)aNode.GetNodeType() == eHTMLTag_br
-          && key.Equals(NS_LITERAL_STRING("type"), nsCaseInsensitiveStringComparator())
-               && value.Equals(NS_LITERAL_STRING("_moz")))
+          && (!Compare((key, NS_LITERAL_STRING("type"), nsCaseInsensitiveStringComparator())
+               && value.Equals(NS_LITERAL_STRING("_moz")))))
         continue;
 
       if (mLowerCaseTags == PR_TRUE)
@@ -456,8 +456,8 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
 
       // Make all links absolute when converting only the selection:
       if ((mFlags & nsIDocumentEncoder::OutputAbsoluteLinks)
-          && (key.Equals(NS_LITERAL_STRING("href"), nsCaseInsensitiveStringComparator())
-              || key.Equals(NS_LITERAL_STRING("src"), nsCaseInsensitiveStringComparator())
+          && (!Compare(key, NS_LITERAL_STRING("href"), nsCaseInsensitiveStringComparator())
+              || !Compare(key, NS_LITERAL_STRING("src"), nsCaseInsensitiveStringComparator())
               // Would be nice to handle OBJECT and APPLET tags,
               // but that gets more complicated since we have to
               // search the tag list for CODEBASE as well.
diff --git a/htmlparser/src/nsViewSourceHTML.cpp b/htmlparser/src/nsViewSourceHTML.cpp
index 9e7baa2b6bf..a281af4f712 100644
--- a/htmlparser/src/nsViewSourceHTML.cpp
+++ b/htmlparser/src/nsViewSourceHTML.cpp
@@ -1203,7 +1203,7 @@ NS_IMETHODIMP CViewSourceHTML::HandleToken(CToken* aToken,nsIParser* aParser) {
       {
         nsAutoString theStr;
         theStr.Assign(aToken->GetStringValue());
-        if(!theStr.Equals(NS_LITERAL_STRING("XI"), nsCaseInsensitiveStringComparator())) {
+        if(Compare(theStr, NS_LITERAL_STRING("XI"), nsCaseInsensitiveStringComparator()) != 0) {
           PRUnichar theChar=theStr.CharAt(0);
           if((nsCRT::IsAsciiDigit(theChar)) || ('X'==theChar) || ('x'==theChar)){
             theStr.Assign(NS_LITERAL_STRING("#") + theStr);
diff --git a/intl/chardet/src/nsMetaCharsetObserver.cpp b/intl/chardet/src/nsMetaCharsetObserver.cpp
index cb2e5cbf006..74073789e6a 100644
--- a/intl/chardet/src/nsMetaCharsetObserver.cpp
+++ b/intl/chardet/src/nsMetaCharsetObserver.cpp
@@ -106,8 +106,7 @@ NS_IMETHODIMP nsMetaCharsetObserver::Notify(
                      const PRUnichar* valueArray[])
 {
   
-    if(!nsDependentString(aTag).Equals(NS_LITERAL_STRING("META"),
-                                       nsCaseInsensitiveStringComparator())) 
+    if(0 != Compare(nsDependentString(aTag), NS_LITERAL_STRING("META"), nsCaseInsensitiveStringComparator())) 
         return NS_ERROR_ILLEGAL_VALUE;
     else
         return Notify(aDocumentID, numOfAttributes, nameArray, valueArray);
@@ -148,8 +147,8 @@ NS_IMETHODIMP nsMetaCharsetObserver::Notify(
                      const PRUnichar* aTag, 
                      const nsStringArray* keys, const nsStringArray* values)
 {
-    if(!nsDependentString(aTag).Equals(NS_LITERAL_STRING("META"),
-                                       nsCaseInsensitiveStringComparator())) 
+    if(0 != Compare(nsDependentString(aTag), NS_LITERAL_STRING("META"),
+                    nsCaseInsensitiveStringComparator())) 
         return NS_ERROR_ILLEGAL_VALUE;
     else
         return Notify(aWebShell, aChannel, keys, values);
@@ -216,14 +215,17 @@ NS_IMETHODIMP nsMetaCharsetObserver::Notify(
         while(IS_SPACE_CHARS(*keyStr)) 
           keyStr++;
 
-        if(Substring(keyStr, keyStr+10).Equals(NS_LITERAL_STRING("HTTP-EQUIV"),
-                                               nsCaseInsensitiveStringComparator()))
+        if(0 == Compare(Substring(keyStr, keyStr+10),
+                        NS_LITERAL_STRING("HTTP-EQUIV"),
+                        nsCaseInsensitiveStringComparator()))
               httpEquivValue = values->StringAt(i)->get();
-        else if(Substring(keyStr, keyStr+7).Equals(NS_LITERAL_STRING("content"),
-                                                   nsCaseInsensitiveStringComparator()))
+        else if(0 == Compare(Substring(keyStr, keyStr+7),
+                             NS_LITERAL_STRING("content"),
+                             nsCaseInsensitiveStringComparator()))
               contentValue = values->StringAt(i)->get();
-        else if (Substring(keyStr, keyStr+7).Equals(NS_LITERAL_STRING("charset"),
-                                                    nsCaseInsensitiveStringComparator()))
+        else if (0 == Compare(Substring(keyStr, keyStr+7),
+                              NS_LITERAL_STRING("charset"),
+                              nsCaseInsensitiveStringComparator()))
               charsetValue = values->StringAt(i)->get();
       }
       NS_NAMED_LITERAL_STRING(contenttype, "Content-Type");
@@ -239,26 +241,26 @@ NS_IMETHODIMP nsMetaCharsetObserver::Notify(
 
       if(
           // first try unquoted strings
-         ((Substring(httpEquivValue,
-                     httpEquivValue+contenttype.Length()).Equals(contenttype,
-                                                                 nsCaseInsensitiveStringComparator())) ||
+         ((0==Compare(Substring(httpEquivValue,httpEquivValue+contenttype.Length()),
+                      contenttype,
+                      nsCaseInsensitiveStringComparator())) ||
           // now try "quoted" or 'quoted' strings
           (( (httpEquivValue[0]=='\'') ||
              (httpEquivValue[0]=='\"') ) && 
-           (Substring(httpEquivValue+1,
-                      httpEquivValue+1+contenttype.Length()).Equals(contenttype,
-                                                                    nsCaseInsensitiveStringComparator()))
+           (0==Compare(Substring(httpEquivValue+1, httpEquivValue+1+contenttype.Length()),
+                       contenttype,
+                       nsCaseInsensitiveStringComparator()))
           )) &&
           // first try unquoted strings
-         ((Substring(contentValue,
-                     contentValue+texthtml.Length()).Equals(texthtml,
-                                                            nsCaseInsensitiveStringComparator())) ||
+         ((0==Compare(Substring(contentValue,contentValue+texthtml.Length()),
+                      texthtml,
+                      nsCaseInsensitiveStringComparator())) ||
           // now try "quoted" or 'quoted' strings
           (((contentValue[0]=='\'') ||
             (contentValue[0]=='\"'))&&
-           (Substring(contentValue+1,
-                      contentValue+1+texthtml.Length()).Equals(texthtml,
-                                                               nsCaseInsensitiveStringComparator()))
+           (0==Compare(Substring(contentValue+1, contentValue+1+texthtml.Length()),
+                       texthtml,
+                       nsCaseInsensitiveStringComparator()))
           ))
         )
       {
@@ -350,8 +352,8 @@ NS_IMETHODIMP nsMetaCharsetObserver::GetCharsetFromCompatibilityTag(
     // e.g. <META charset="ISO-8859-1">
     PRInt32 numOfAttributes = keys->Count();
     if ((numOfAttributes >= 3) &&
-        (keys->StringAt(0)->Equals(NS_LITERAL_STRING("charset"),
-                                   nsCaseInsensitiveStringComparator())))
+        (0 == Compare(*keys->StringAt(0), NS_LITERAL_STRING("charset"),
+                      nsCaseInsensitiveStringComparator())))
     {
       nsAutoString srcStr((values->StringAt(numOfAttributes-2))->get());
       PRInt32 err;
diff --git a/intl/chardet/src/nsXMLEncodingObserver.cpp b/intl/chardet/src/nsXMLEncodingObserver.cpp
index aa437feccc1..fa12c04a90c 100644
--- a/intl/chardet/src/nsXMLEncodingObserver.cpp
+++ b/intl/chardet/src/nsXMLEncodingObserver.cpp
@@ -94,8 +94,8 @@ NS_IMETHODIMP nsXMLEncodingObserver::Notify(
                      const PRUnichar* nameArray[], 
                      const PRUnichar* valueArray[])
 {
-    if(!nsDependentString(aTag).Equals(NS_LITERAL_STRING("?XML"),
-                                       nsCaseInsensitiveStringComparator())) 
+    if(0 != Compare(nsDependentString(aTag), NS_LITERAL_STRING("?XML"),
+                    nsCaseInsensitiveStringComparator())) 
         return NS_ERROR_ILLEGAL_VALUE;
     else
         return Notify(aDocumentID, numOfAttributes, nameArray, valueArray);
@@ -143,8 +143,8 @@ NS_IMETHODIMP nsXMLEncodingObserver::Notify(
          } else if(0==nsCRT::strcmp(nameArray[i], NS_LITERAL_STRING("charsetSource").get())) {
            bGotCurrentCharsetSource = PR_TRUE;
            charsetSourceStr = valueArray[i];
-         } else if(nsDependentString(nameArray[i]).Equals(NS_LITERAL_STRING("encoding"),
-                                                          nsCaseInsensitiveStringComparator())) { 
+         } else if(0==Compare(nsDependentString(nameArray[i]), NS_LITERAL_STRING("encoding"),
+                              nsCaseInsensitiveStringComparator())) { 
            bGotEncoding = PR_TRUE;
            encoding = valueArray[i];
          }
diff --git a/intl/locale/src/unix/nsCollationUnix.cpp b/intl/locale/src/unix/nsCollationUnix.cpp
index 392e0420ca4..a73e33c6a6a 100644
--- a/intl/locale/src/unix/nsCollationUnix.cpp
+++ b/intl/locale/src/unix/nsCollationUnix.cpp
@@ -96,9 +96,7 @@ nsresult nsCollationUnix::Initialize(nsILocale* locale)
     PRUnichar *prefValue;
     res = prefs->GetLocalizedUnicharPref("intl.collationOption", &prefValue);
     if (NS_SUCCEEDED(res)) {
-      mUseCodePointOrder =
-        nsDependentString(prefValue).Equals(NS_LITERAL_STRING("useCodePointOrder"),
-                                            nsCaseInsensitiveStringComparator());
+      mUseCodePointOrder = (Compare(nsDependentString(prefValue), NS_LITERAL_STRING("useCodePointOrder"), nsCaseInsensitiveStringComparator())==0);
       nsMemory::Free(prefValue);
     }
   }
diff --git a/intl/uconv/src/nsCharsetAliasImp.cpp b/intl/uconv/src/nsCharsetAliasImp.cpp
index 813c572f8ab..a2a479348b6 100644
--- a/intl/uconv/src/nsCharsetAliasImp.cpp
+++ b/intl/uconv/src/nsCharsetAliasImp.cpp
@@ -127,7 +127,7 @@ NS_IMETHODIMP nsCharsetAlias2::Equals(const nsAReadableString& aCharset1, const
 {
    nsresult res = NS_OK;
 
-   if(aCharset1.Equals(aCharset2, nsCaseInsensitiveStringComparator())) {
+   if(Compare(aCharset1, aCharset2, nsCaseInsensitiveStringComparator()) == 0) {
       *oResult = PR_TRUE;
       return res;
    }
diff --git a/mailnews/absync/src/nsAbSync.cpp b/mailnews/absync/src/nsAbSync.cpp
index 46f5a62e8a8..842d76840a2 100644
--- a/mailnews/absync/src/nsAbSync.cpp
+++ b/mailnews/absync/src/nsAbSync.cpp
@@ -2816,20 +2816,15 @@ nsAbSync::GetTypeOfPhoneNumber(nsString tagName)
         continue;
       
       phoneType.Cut(0, loc+1);
-      if (phoneType.Equals(NS_LITERAL_STRING(ABSYNC_HOME_PHONE_TYPE),
-                           nsCaseInsensitiveStringComparator()))
+      if (!Compare(phoneType, NS_LITERAL_STRING(ABSYNC_HOME_PHONE_TYPE), nsCaseInsensitiveStringComparator()))
         return ABSYNC_HOME_PHONE_ID;
-      else if (phoneType.Equals(NS_LITERAL_STRING(ABSYNC_WORK_PHONE_TYPE),
-                                nsCaseInsensitiveStringComparator()))
+      else if (!Compare(phoneType, NS_LITERAL_STRING(ABSYNC_WORK_PHONE_TYPE), nsCaseInsensitiveStringComparator()))
         return ABSYNC_WORK_PHONE_ID;
-      else if (phoneType.Equals(NS_LITERAL_STRING(ABSYNC_FAX_PHONE_TYPE),
-                                nsCaseInsensitiveStringComparator()))
+      else if (!Compare(phoneType, NS_LITERAL_STRING(ABSYNC_FAX_PHONE_TYPE), nsCaseInsensitiveStringComparator()))
         return ABSYNC_FAX_PHONE_ID;
-      else if (phoneType.Equals(NS_LITERAL_STRING(ABSYNC_PAGER_PHONE_TYPE),
-                                nsCaseInsensitiveStringComparator()))
+      else if (!Compare(phoneType, NS_LITERAL_STRING(ABSYNC_PAGER_PHONE_TYPE), nsCaseInsensitiveStringComparator()))
         return ABSYNC_PAGER_PHONE_ID;
-      else if (phoneType.Equals(NS_LITERAL_STRING(ABSYNC_CELL_PHONE_TYPE),
-                                nsCaseInsensitiveStringComparator()))
+      else if (!Compare(phoneType, NS_LITERAL_STRING(ABSYNC_CELL_PHONE_TYPE), nsCaseInsensitiveStringComparator()))
         return ABSYNC_CELL_PHONE_ID;
     }
   }
@@ -2919,8 +2914,7 @@ nsAbSync::AddValueToNewCard(nsIAbCard *aCard, nsString *aTagName, nsString *aTag
     PR_FREEIF(tValue);
   }
 
-  if (Substring(*aTagName, 0, 5).Equals(NS_LITERAL_STRING("phone"),
-                                        nsCaseInsensitiveStringComparator()))
+  if (!Compare(Substring(*aTagName, 0, 5), NS_LITERAL_STRING("phone"), nsCaseInsensitiveStringComparator()))
   {
     nsString      tempVal;
     tempVal.Append(*aTagName +
diff --git a/mailnews/addrbook/src/nsAbAutoCompleteSession.cpp b/mailnews/addrbook/src/nsAbAutoCompleteSession.cpp
index 750489fbc45..6d8e721931b 100644
--- a/mailnews/addrbook/src/nsAbAutoCompleteSession.cpp
+++ b/mailnews/addrbook/src/nsAbAutoCompleteSession.cpp
@@ -100,8 +100,8 @@ PRBool nsAbAutoCompleteSession::ItsADuplicate(PRUnichar* fullAddrStr, nsIAutoCom
                         rv = resultItem->GetValue(valueStr);
                         if (NS_SUCCEEDED(rv) && !valueStr.IsEmpty())
                         {
-                          if (nsDependentString(fullAddrStr).Equals(valueStr,
-                                                                    nsCaseInsensitiveStringComparator()))
+                          if (Compare(nsDependentString(fullAddrStr), valueStr,
+                                      nsCaseInsensitiveStringComparator())==0)
                             return PR_TRUE;
                         }
                     }
@@ -266,9 +266,9 @@ static PRBool CommonPrefix(const PRUnichar *aString, const PRUnichar *aSubstr, P
   if (!aSubstrLen || (nsCRT::strlen(aString) < NS_STATIC_CAST(PRUint32, aSubstrLen)))
     return PR_FALSE;
 
-  return (Substring(aString,
-                    aString+aSubstrLen).Equals(Substring(aSubstr, aSubstr+aSubstrLen),
-                                               nsCaseInsensitiveStringComparator()));
+  return (Compare(Substring(aString, aString+aSubstrLen),
+                  Substring(aSubstr, aSubstr+aSubstrLen),
+                  nsCaseInsensitiveStringComparator()) == 0);
 }
 
 
@@ -295,48 +295,46 @@ nsAbAutoCompleteSession::CheckEntry(nsAbAutoCompleteSearchString* searchStr,
     fullStringLen = searchStr->mFullStringLen;
   }
 
-  nsDependentString fullStringStr(fullString, fullStringLen);
-  
   // First check for a Nickname exact match
-  if (nickName &&
-      fullStringStr.Equals(nsDependentString(nickName),
-                           nsCaseInsensitiveStringComparator()))
+  if (nickName && Compare(nsDependentString(fullString),
+                          nsDependentString(nickName),
+                          nsCaseInsensitiveStringComparator()) == 0)
   {
     *matchType = NICKNAME_EXACT_MATCH;
     return PR_TRUE;
   }
 
   // Then check for a display Name exact match
-  if (displayName &&
-      fullStringStr.Equals(nsDependentString(displayName),
-                           nsCaseInsensitiveStringComparator()))
+  if (displayName && Compare(nsDependentString(fullString),
+                             nsDependentString(displayName),
+                             nsCaseInsensitiveStringComparator()) == 0)
   {
     *matchType = NAME_EXACT_MATCH;
     return PR_TRUE;
   }
 
   // Then check for a fisrt Name exact match
-  if (firstName &&
-      fullStringStr.Equals(nsDependentString(firstName),
-                           nsCaseInsensitiveStringComparator()))
+  if (firstName && Compare(nsDependentString(fullString),
+                           nsDependentString(firstName),
+                           nsCaseInsensitiveStringComparator()) == 0)
   {
     *matchType = NAME_EXACT_MATCH;
     return PR_TRUE;
   }
 
   // Then check for a last Name exact match
-  if (lastName &&
-      fullStringStr.Equals(nsDependentString(lastName),
-                           nsCaseInsensitiveStringComparator()))
+  if (lastName && Compare(nsDependentString(fullString),
+                          nsDependentString(lastName),
+                          nsCaseInsensitiveStringComparator()) == 0)
   {
     *matchType = NAME_EXACT_MATCH;
     return PR_TRUE;
   }
 
   // Then check for a Email exact match
-  if (emailAddress &&
-      fullStringStr.Equals(nsDependentString(emailAddress),
-                           nsCaseInsensitiveStringComparator()))
+  if (emailAddress && Compare(nsDependentString(fullString),
+                              nsDependentString(emailAddress),
+                              nsCaseInsensitiveStringComparator()) == 0)
   {
     *matchType = EMAIL_EXACT_MATCH;
     return PR_TRUE;
diff --git a/mailnews/base/src/nsMsgAccountManager.cpp b/mailnews/base/src/nsMsgAccountManager.cpp
index 5186722d3c7..4766138c598 100644
--- a/mailnews/base/src/nsMsgAccountManager.cpp
+++ b/mailnews/base/src/nsMsgAccountManager.cpp
@@ -1037,9 +1037,7 @@ PRBool PR_CALLBACK nsMsgAccountManager::cleanupOnExit(nsHashKey *aKey, void *aDa
                nsCOMPtr<nsIMsgFolder>inboxFolder = do_QueryInterface(aSupport);
                nsXPIDLString folderName;
                inboxFolder->GetName(getter_Copies(folderName));
-               if (folderName &&
-                   folderName.Equals(NS_LITERAL_STRING("INBOX"),
-                                     nsCaseInsensitiveStringComparator()))
+               if (folderName && Compare(folderName, NS_LITERAL_STRING("INBOX"), nsCaseInsensitiveStringComparator()) ==0)
                {
                  rv1 = inboxFolder->Compact(urlListener, nsnull /* msgwindow */);
                  if (NS_SUCCEEDED(rv1))
diff --git a/mailnews/base/util/nsMsgFolder.cpp b/mailnews/base/util/nsMsgFolder.cpp
index f742d949d52..cf8b7d43a73 100644
--- a/mailnews/base/util/nsMsgFolder.cpp
+++ b/mailnews/base/util/nsMsgFolder.cpp
@@ -938,9 +938,8 @@ NS_IMETHODIMP nsMsgFolder::GetChildNamed(const char *name, nsISupports ** aChild
 
 			rv = folder->GetName(getter_Copies(folderName));
 			// case-insensitive compare is probably LCD across OS filesystems
-			if (NS_SUCCEEDED(rv) &&
-          folderName.Equals(uniName,
-                            nsCaseInsensitiveStringComparator()))
+			if (NS_SUCCEEDED(rv) && Compare(folderName, uniName,
+                                      nsCaseInsensitiveStringComparator()) == 0)
 			{
 				*aChild = folder;
 				NS_ADDREF(*aChild);
diff --git a/mailnews/base/util/nsMsgI18N.cpp b/mailnews/base/util/nsMsgI18N.cpp
index a7ebcc3d617..838e037a601 100644
--- a/mailnews/base/util/nsMsgI18N.cpp
+++ b/mailnews/base/util/nsMsgI18N.cpp
@@ -438,8 +438,7 @@ PRBool nsMsgI18Nmultibyte_charset(const char *charset)
     if (NS_SUCCEEDED(res)) {
       res = ccm2->GetCharsetData2(charsetAtom, NS_LITERAL_STRING(".isMultibyte").get(), &charsetData);
       if (NS_SUCCEEDED(res)) {
-        result = charsetData.Equals(NS_LITERAL_STRING("true"),
-                                    nsCaseInsensitiveStringComparator());
+        result = !Compare(charsetData, NS_LITERAL_STRING("true"), nsCaseInsensitiveStringComparator());
       }
     }
   }
diff --git a/mailnews/compose/src/nsMsgCompose.cpp b/mailnews/compose/src/nsMsgCompose.cpp
index dd1e11ab779..8e557bc2bf4 100644
--- a/mailnews/compose/src/nsMsgCompose.cpp
+++ b/mailnews/compose/src/nsMsgCompose.cpp
@@ -2324,8 +2324,9 @@ nsresult nsMsgComposeSendListener::OnStopSending(const char *aMsgID, nsresult aS
       {
         if (!fieldsFCC.IsEmpty())
         {
-          if (fieldsFCC.Equals(NS_LITERAL_STRING("nocopy://"),
-                               nsCaseInsensitiveStringComparator()))
+          if (Compare(nsDependentString(fieldsFCC),
+                      NS_LITERAL_STRING("nocopy://"),
+                      nsCaseInsensitiveStringComparator()) == 0)
           {
             compose->NotifyStateListeners(eComposeProcessDone, NS_OK);
             if (progress)
@@ -3800,8 +3801,7 @@ nsresult nsMsgCompose::TagConvertible(nsIDOMNode *node,  PRInt32 *_retval)
           if (NS_SUCCEEDED(pItem->GetNodeValue(typeValue)))
           {
             typeValue.StripChars("\"");
-            if (typeValue.Equals(NS_LITERAL_STRING("cite"),
-                                 nsCaseInsensitiveStringComparator()))
+            if (!Compare(typeValue, NS_LITERAL_STRING("cite"), nsCaseInsensitiveStringComparator()))
               *_retval = nsIMsgCompConvertible::Plain;
           }
         }
diff --git a/mailnews/compose/src/nsMsgSend.cpp b/mailnews/compose/src/nsMsgSend.cpp
index e79760a1f9e..a9ff3948ac1 100644
--- a/mailnews/compose/src/nsMsgSend.cpp
+++ b/mailnews/compose/src/nsMsgSend.cpp
@@ -1680,8 +1680,7 @@ nsMsgComposeAndSend::ProcessMultipartRelated(PRInt32 *aMailboxCount, PRInt32 *aN
       nsAutoString attributeValue;
       if (NS_SUCCEEDED(domElement->GetAttribute(NS_LITERAL_STRING("moz-do-not-send"), attributeValue)))
       {
-        if (attributeValue.Equals(NS_LITERAL_STRING("true"),
-                                  nsCaseInsensitiveStringComparator()))
+        if (!Compare(attributeValue, NS_LITERAL_STRING("true"), nsCaseInsensitiveStringComparator()))
           continue;
       }
     }
diff --git a/mailnews/imap/src/nsImapMailFolder.cpp b/mailnews/imap/src/nsImapMailFolder.cpp
index 36d1661a5f3..0562e3811b7 100644
--- a/mailnews/imap/src/nsImapMailFolder.cpp
+++ b/mailnews/imap/src/nsImapMailFolder.cpp
@@ -710,12 +710,12 @@ NS_IMETHODIMP nsImapMailFolder::CreateSubfolder(const PRUnichar* folderName, nsI
     nsresult rv = NS_ERROR_NULL_POINTER;
     if (!folderName) return rv;
 
-    if ( nsDependentString(folderName).Equals(NS_LITERAL_STRING("Trash"),nsCaseInsensitiveStringComparator()) )   // Trash , a special folder
+    if ( Compare(nsDependentString(folderName),NS_LITERAL_STRING("Trash"),nsCaseInsensitiveStringComparator()) == 0 )   // Trash , a special folder
     {
         AlertSpecialFolderExists(msgWindow);
         return NS_MSG_FOLDER_EXISTS;
     }
-    else if ( nsDependentString(folderName).Equals(NS_LITERAL_STRING("Inbox"),nsCaseInsensitiveStringComparator()) )  // Inbox, a special folder
+    else if ( Compare(nsDependentString(folderName),NS_LITERAL_STRING("Inbox"),nsCaseInsensitiveStringComparator()) == 0 )  // Inbox, a special folder
     {
         AlertSpecialFolderExists(msgWindow);
         return NS_MSG_FOLDER_EXISTS;
@@ -3923,8 +3923,9 @@ PRBool nsImapMailFolder::ShowDeletedMessages()
         {
           nsXPIDLString folderName;
           GetName(getter_Copies(folderName));
-          if (Substring(folderName,0,convertedName.Length()).Equals(convertedName,
-                                                                    nsCaseInsensitiveStringComparator()))
+          if (!Compare(Substring(folderName,0,convertedName.Length()),
+                       convertedName,
+                       nsCaseInsensitiveStringComparator()))
             showDeleted = PR_TRUE;
         }
       }
diff --git a/mailnews/import/eudora/src/nsEudoraCompose.cpp b/mailnews/import/eudora/src/nsEudoraCompose.cpp
index ea68be524be..85cdc2a9288 100644
--- a/mailnews/import/eudora/src/nsEudoraCompose.cpp
+++ b/mailnews/import/eudora/src/nsEudoraCompose.cpp
@@ -504,7 +504,7 @@ void nsEudoraCompose::ExtractType( nsString& str)
 	// valid multipart!
 	if (str.Length() > 10) {
 		str.Left( tStr, 10);
-		if (tStr.Equals(NS_LITERAL_STRING("multipart/"), nsCaseInsensitiveStringComparator()))
+		if (!Compare(tStr, NS_LITERAL_STRING("multipart/"), nsCaseInsensitiveStringComparator()))
 			str.Truncate();
 	}
 }
diff --git a/mailnews/import/eudora/src/nsEudoraMac.cpp b/mailnews/import/eudora/src/nsEudoraMac.cpp
index 940be7c2060..8d2d7537586 100644
--- a/mailnews/import/eudora/src/nsEudoraMac.cpp
+++ b/mailnews/import/eudora/src/nsEudoraMac.cpp
@@ -1030,7 +1030,7 @@ PRBool nsEudoraMac::IsValidMailboxName( nsCString& fName)
 {
 	if (m_depth > 1)
 		return( PR_TRUE);
-	if (fName.Equals(NS_LITERAL_CSTRING("Eudora Nicknames"), nsCaseInsensitiveCStringComparator()))
+	if (!Compare(fName, NS_LITERAL_CSTRING("Eudora Nicknames"), nsCaseInsensitiveCStringComparator()))
 		return( PR_FALSE);
 	return( PR_TRUE);
 }
diff --git a/mailnews/import/eudora/src/nsEudoraWin32.cpp b/mailnews/import/eudora/src/nsEudoraWin32.cpp
index 3784a61a386..8910eff507e 100644
--- a/mailnews/import/eudora/src/nsEudoraWin32.cpp
+++ b/mailnews/import/eudora/src/nsEudoraWin32.cpp
@@ -694,7 +694,7 @@ void nsEudoraWin32::GetAccountName( const char *pSection, nsString& str)
 
 	nsCString	s(pSection);
 	
-	if (s.Equals(NS_LITERAL_CSTRING("Settings"), nsCaseInsensitiveCStringComparator())) {
+	if (!Compare(s, NS_LITERAL_CSTRING("Settings"), nsCaseInsensitiveCStringComparator())) {
 		str.Assign(NS_LITERAL_STRING("Eudora "));
 		str.AppendWithConversion( pSection);
 	}
@@ -703,7 +703,7 @@ void nsEudoraWin32::GetAccountName( const char *pSection, nsString& str)
 		str.AssignWithConversion(pSection);
 		if (s.Length() > 8) {
 			s.Left( tStr, 8); 
-			if (tStr.Equals(NS_LITERAL_CSTRING("Persona-"), nsCaseInsensitiveCStringComparator())) {
+			if (!Compare(tStr, NS_LITERAL_CSTRING("Persona-"), nsCaseInsensitiveCStringComparator())) {
 				s.Right( tStr, s.Length() - 8);
 				str.AssignWithConversion(tStr.get());
 			}
@@ -1378,8 +1378,9 @@ nsresult nsEudoraWin32::FoundAddressBook( nsIFileSpec *spec, const PRUnichar *pN
 		nsCRT::free( pLeaf);
 		nsString	tStr;
 		name.Right( tStr, 4);
-		if (tStr.Equals(NS_LITERAL_STRING(".txt"),
-                        nsCaseInsensitiveStringComparator())) {
+		if (! Compare(tStr,
+                      NS_LITERAL_STRING(".txt"),
+                      nsCaseInsensitiveStringComparator())) {
 			name.Left( tStr, name.Length() - 4);
 			name = tStr;
 		}
diff --git a/mailnews/import/oexpress/nsOEScanBoxes.cpp b/mailnews/import/oexpress/nsOEScanBoxes.cpp
index dc6006cec27..88f178d0ed7 100644
--- a/mailnews/import/oexpress/nsOEScanBoxes.cpp
+++ b/mailnews/import/oexpress/nsOEScanBoxes.cpp
@@ -293,7 +293,7 @@ PRBool nsOEScanBoxes::FindMailBoxes( nsIFileSpec* descFile)
 		#endif
 		
 		pEntry->fileName.Right( ext, 4);
-		if (!ext.Equals(mbxExt))
+		if (Compare(ext, mbxExt))
 			pEntry->fileName.Append( ".mbx");		
 		
 		m_entryArray.AppendElement( pEntry);
diff --git a/mailnews/import/outlook/src/MapiApi.cpp b/mailnews/import/outlook/src/MapiApi.cpp
index 28e409b93d5..5e3deaeb84f 100644
--- a/mailnews/import/outlook/src/MapiApi.cpp
+++ b/mailnews/import/outlook/src/MapiApi.cpp
@@ -306,25 +306,24 @@ CGetStoreFoldersIter::CGetStoreFoldersIter( CMapiApi *pApi, CMapiFolderList& fol
 BOOL CGetStoreFoldersIter::ExcludeFolderClass( const PRUnichar *pName)
 {
 	BOOL bResult;
-    nsDependentString pNameStr(pName);
 	if (m_isMail) {
 		bResult = FALSE;
-        if (pNameStr.Equals(NS_LITERAL_STRING("IPF.Appointment")))
+        if (!Compare(nsDependentString(pName), NS_LITERAL_STRING("IPF.Appointment")))
 			bResult = TRUE;
-		else if (pNameStr.Equals(NS_LITERAL_STRING("IPF.Contact")))
+		else if (!Compare(nsDependentString(pName), NS_LITERAL_STRING("IPF.Contact")))
 			bResult = TRUE;
-		else if (pNameStr.Equals(NS_LITERAL_STRING("IPF.Journal")))
+		else if (!Compare(nsDependentString(pName), NS_LITERAL_STRING("IPF.Journal")))
 			bResult = TRUE;
-        else if (pNameStr.Equals(NS_LITERAL_STRING("IPF.StickyNote")))
+        else if (!Compare(nsDependentString(pName), NS_LITERAL_STRING("IPF.StickyNote")))
 			bResult = TRUE;
-		else if (pNameStr.Equals(NS_LITERAL_STRING("IPF.Task")))
+		else if (!Compare(nsDependentString(pName), NS_LITERAL_STRING("IPF.Task")))
 			bResult = TRUE;
 		// else if (!stricmp( pName, "IPF.Note"))
 		//	bResult = TRUE;
 	}
 	else {
 		bResult = TRUE;
-		if (pNameStr.Equals(NS_LITERAL_STRING("IPF.Contact")))
+		if (!Compare( nsDependentString(pName), NS_LITERAL_STRING("IPF.Contact")))
 			bResult = FALSE;
 	}
 
diff --git a/mailnews/local/src/nsLocalMailFolder.cpp b/mailnews/local/src/nsLocalMailFolder.cpp
index 0062841a3b8..c5a25783819 100644
--- a/mailnews/local/src/nsLocalMailFolder.cpp
+++ b/mailnews/local/src/nsLocalMailFolder.cpp
@@ -801,8 +801,8 @@ nsMsgLocalMailFolder::CheckIfFolderExists(const PRUnichar *folderName, nsFileSpe
       PR_FREEIF(leaf);
 
       if (!leafName.IsEmpty() &&
-          leafName.Equals(nsDependentString(folderName), 
-                          nsCaseInsensitiveStringComparator()))
+          Compare(nsDependentString(folderName), leafName,
+                  nsCaseInsensitiveStringComparator()) == 0)
       {
            if (msgWindow)
               AlertFolderExists(msgWindow);
diff --git a/netwerk/cache/src/nsCacheEntry.cpp b/netwerk/cache/src/nsCacheEntry.cpp
index c62a1907e07..3131215e25c 100644
--- a/netwerk/cache/src/nsCacheEntry.cpp
+++ b/netwerk/cache/src/nsCacheEntry.cpp
@@ -591,7 +591,7 @@ nsCacheEntryHashTable::MatchEntry(PLDHashTable *       /* table */,
     NS_ASSERTION(key !=  nsnull, "### nsCacheEntryHashTable::MatchEntry : null key");
     nsCacheEntry *cacheEntry = ((nsCacheEntryHashTableEntry *)hashEntry)->cacheEntry;
 
-    return cacheEntry->mKey->Equals(*(nsCString *)key);
+    return Compare(*cacheEntry->mKey, *(nsCString *)key) == 0;
 }
 
 
diff --git a/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp b/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp
index 2813b875e7f..6effaa73c82 100644
--- a/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp
+++ b/netwerk/protocol/ftp/src/nsFtpConnectionThread.cpp
@@ -2132,7 +2132,7 @@ nsFtpState::SendFTPCommand(nsCString& command)
     
     // we don't want to log the password:
     nsCAutoString logcmd(command);
-    if (Substring(command, 0, 5).Equals(NS_LITERAL_CSTRING("PASS "))) 
+    if (Compare(Substring(command, 0, 5), NS_LITERAL_CSTRING("PASS ")) == 0) 
         logcmd = "PASS xxxxx";
     
     PR_LOG(gFTPLog, PR_LOG_DEBUG, ("(%x)(dwait=%d) Writing \"%s\"\n", this, mWaitingForDConn, logcmd.get()));
diff --git a/netwerk/streamconv/converters/mozTXTToHTMLConv.cpp b/netwerk/streamconv/converters/mozTXTToHTMLConv.cpp
index 3f1f21384a6..dee8a652e5e 100644
--- a/netwerk/streamconv/converters/mozTXTToHTMLConv.cpp
+++ b/netwerk/streamconv/converters/mozTXTToHTMLConv.cpp
@@ -542,10 +542,11 @@ mozTXTToHTMLConv::ItMatchesDelimited(const PRUnichar * aInString,
           nsCRT::IsAsciiDigit(textAfterPos) ||
           textAfterPos == *rep
         ) ||
-        !Substring(nsDependentString(aInString, aInLength),
-                   (before == LT_IGNORE ? 0 : 1),
-                   aRepLen).Equals(nsDependentString(rep, aRepLen),
-                                   nsCaseInsensitiveStringComparator())
+        Compare(Substring(nsDependentString(aInString, aInLength),
+                          (before == LT_IGNORE ? 0 : 1),
+                          aRepLen),
+                nsDependentString(rep, aRepLen),
+                nsCaseInsensitiveStringComparator())
     )
     return PR_FALSE;
 
@@ -977,9 +978,8 @@ mozTXTToHTMLConv::CiteLevelTXT(const PRUnichar *line,
       const PRUnichar * indexString = &line[logLineStart];
            // here, |logLineStart < lineLength| is always true
       PRUint32 minlength = MinInt(6,nsCRT::strlen(indexString));
-      if (Substring(indexString,
-                    indexString+minlength).Equals(Substring(NS_LITERAL_STRING(">From "), 0, minlength),
-                                                  nsCaseInsensitiveStringComparator()))
+      if (!Compare(Substring(indexString, indexString+minlength),
+                   Substring(NS_LITERAL_STRING(">From "), 0, minlength), nsCaseInsensitiveStringComparator()))
         //XXX RFC2646
         moreCites = PR_FALSE;
       else
diff --git a/netwerk/streamconv/converters/nsUnknownDecoder.cpp b/netwerk/streamconv/converters/nsUnknownDecoder.cpp
index ce7778f147a..276196779c3 100644
--- a/netwerk/streamconv/converters/nsUnknownDecoder.cpp
+++ b/netwerk/streamconv/converters/nsUnknownDecoder.cpp
@@ -304,10 +304,8 @@ void nsUnknownDecoder::DetermineContentType(nsIRequest* request)
   //
   // If the buffer begins with a mailbox delimiter then it is not HTML
   //
-  else if (Substring(str, 0, 5).Equals(NS_LITERAL_CSTRING("From "),
-                                       nsCaseInsensitiveCStringComparator()) ||
-           Substring(str, 0, 6).Equals(NS_LITERAL_CSTRING(">From "),
-                                       nsCaseInsensitiveCStringComparator())) {
+  else if (!Compare(Substring(str, 0, 5), NS_LITERAL_CSTRING("From "), nsCaseInsensitiveCStringComparator()) || 
+           !Compare(Substring(str, 0, 6), NS_LITERAL_CSTRING(">From "), nsCaseInsensitiveCStringComparator())) {
     mContentType = TEXT_PLAIN;
   }
   //
diff --git a/parser/htmlparser/src/CNavDTD.cpp b/parser/htmlparser/src/CNavDTD.cpp
index e424a0e72bc..3c5474218f0 100644
--- a/parser/htmlparser/src/CNavDTD.cpp
+++ b/parser/htmlparser/src/CNavDTD.cpp
@@ -1013,12 +1013,12 @@ nsresult CNavDTD::DidHandleStartTag(nsIParserNode& aNode,eHTMLTags aChildTag){
         if(theCount) {
           PRInt32 theIndex=0;
           for(theIndex=0;theIndex<theCount;theIndex++){
-            const nsAString& theKey = aNode.GetKeyAt(theIndex);
-            if(theKey.Equals(NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
+            nsAutoString theKey(aNode.GetKeyAt(theIndex));
+            if(!Compare(theKey, NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
               const nsString& theName=aNode.GetValueAt(theIndex);
               theNamePtr=&theName;
             }
-            else if(theKey.Equals(NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
+            else if(!Compare(theKey, NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
               //store the named enity with the context...
               const nsString& theValue=aNode.GetValueAt(theIndex);
               theValuePtr=&theValue;
diff --git a/parser/htmlparser/src/COtherDTD.cpp b/parser/htmlparser/src/COtherDTD.cpp
index a2478a821c2..169aab02185 100644
--- a/parser/htmlparser/src/COtherDTD.cpp
+++ b/parser/htmlparser/src/COtherDTD.cpp
@@ -588,12 +588,12 @@ nsresult COtherDTD::DidHandleStartTag(nsIParserNode& aNode,eHTMLTags aChildTag){
         if(theCount) {
           PRInt32 theIndex=0;
           for(theIndex=0;theIndex<theCount;theIndex++){
-            const nsAString& theKey = aNode.GetKeyAt(theIndex);
-            if(theKey.Equals(NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
+            nsAutoString theKey(aNode.GetKeyAt(theIndex));
+            if(!Compare(theKey, NS_LITERAL_STRING("ENTITY"), nsCaseInsensitiveStringComparator())) {
               const nsString& theName=aNode.GetValueAt(theIndex);
               theNamePtr=&theName;
             }
-            else if(theKey.Equals(NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
+            else if(!Compare(theKey, NS_LITERAL_STRING("VALUE"), nsCaseInsensitiveStringComparator())) {
               //store the named enity with the context...
               const nsString& theValue=aNode.GetValueAt(theIndex);
               theValuePtr=&theValue;
diff --git a/parser/htmlparser/src/nsDTDUtils.cpp b/parser/htmlparser/src/nsDTDUtils.cpp
index 1e13e5169af..e52d467fddf 100644
--- a/parser/htmlparser/src/nsDTDUtils.cpp
+++ b/parser/htmlparser/src/nsDTDUtils.cpp
@@ -842,10 +842,10 @@ PRInt32 nsDTDContext::IncrementCounter(eHTMLTags aTag,nsIParserNode& aNode,nsStr
   CAbacus::eNumFormat  theNumFormat=CAbacus::eDecimal;
 
   for(theIndex=0;theIndex<theCount;theIndex++){
-    const nsAString& theKey=aNode.GetKeyAt(theIndex);
+    nsAutoString theKey(aNode.GetKeyAt(theIndex));
     const nsString& theValue=aNode.GetValueAt(theIndex);
 
-    if(theKey.Equals(NS_LITERAL_STRING("name"), nsCaseInsensitiveStringComparator())){
+    if(!Compare(theKey, NS_LITERAL_STRING("name"), nsCaseInsensitiveStringComparator())){
       theEntity=GetEntity(theValue);
       if(!theEntity) {
         theEntity=RegisterEntity(theValue,theValue);
@@ -853,10 +853,10 @@ PRInt32 nsDTDContext::IncrementCounter(eHTMLTags aTag,nsIParserNode& aNode,nsStr
       }
       aTag=eHTMLTag_userdefined;
     }
-    else if(theKey.Equals(NS_LITERAL_STRING("noincr"), nsCaseInsensitiveStringComparator())){
+    else if(!Compare(theKey, NS_LITERAL_STRING("noincr"), nsCaseInsensitiveStringComparator())){
       theIncrValue=0;
     }
-    else if(theKey.Equals(NS_LITERAL_STRING("format"), nsCaseInsensitiveStringComparator())){
+    else if(!Compare(theKey, NS_LITERAL_STRING("format"), nsCaseInsensitiveStringComparator())){
       PRUnichar theChar=theValue.CharAt(0);
       if('"'==theChar)
         theChar=theValue.CharAt(1);
@@ -873,7 +873,7 @@ PRInt32 nsDTDContext::IncrementCounter(eHTMLTags aTag,nsIParserNode& aNode,nsStr
       }
       //determine numbering style
     }
-    else if(theKey.Equals(NS_LITERAL_STRING("value"), nsCaseInsensitiveStringComparator())){
+    else if(!Compare(theKey, NS_LITERAL_STRING("value"), nsCaseInsensitiveStringComparator())){
       PRInt32 err=0;
       theNewValue=theValue.ToInteger(&err);
       if(!err) {
diff --git a/parser/htmlparser/src/nsHTMLContentSinkStream.cpp b/parser/htmlparser/src/nsHTMLContentSinkStream.cpp
index 62fdfbc57b1..46768dec5fc 100644
--- a/parser/htmlparser/src/nsHTMLContentSinkStream.cpp
+++ b/parser/htmlparser/src/nsHTMLContentSinkStream.cpp
@@ -413,7 +413,7 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
   if(theCount) {
     int i=0;
     for(i=0;i<theCount;i++){
-      const nsAString& key = aNode.GetKeyAt(i);
+      nsAutoString key(aNode.GetKeyAt(i));
       
       // See if there's an attribute:
       // note that we copy here, because we're going to have to trim quotes.
@@ -423,7 +423,7 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
       value.Trim("\"", PR_TRUE, PR_TRUE);
 
       // Filter out any attribute starting with _moz
-      if (key.Equals(NS_LITERAL_STRING("_moz"), nsCaseInsensitiveStringComparator()))
+      if (!Compare(key, NS_LITERAL_STRING("_moz"), nsCaseInsensitiveStringComparator())
         continue;
 
       // 
@@ -437,8 +437,8 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
       // used by the editor.  Bug 16988.  Yuck.
       //
       if ((eHTMLTags)aNode.GetNodeType() == eHTMLTag_br
-          && key.Equals(NS_LITERAL_STRING("type"), nsCaseInsensitiveStringComparator())
-               && value.Equals(NS_LITERAL_STRING("_moz")))
+          && (!Compare((key, NS_LITERAL_STRING("type"), nsCaseInsensitiveStringComparator())
+               && value.Equals(NS_LITERAL_STRING("_moz")))))
         continue;
 
       if (mLowerCaseTags == PR_TRUE)
@@ -456,8 +456,8 @@ void nsHTMLContentSinkStream::WriteAttributes(const nsIParserNode& aNode)
 
       // Make all links absolute when converting only the selection:
       if ((mFlags & nsIDocumentEncoder::OutputAbsoluteLinks)
-          && (key.Equals(NS_LITERAL_STRING("href"), nsCaseInsensitiveStringComparator())
-              || key.Equals(NS_LITERAL_STRING("src"), nsCaseInsensitiveStringComparator())
+          && (!Compare(key, NS_LITERAL_STRING("href"), nsCaseInsensitiveStringComparator())
+              || !Compare(key, NS_LITERAL_STRING("src"), nsCaseInsensitiveStringComparator())
               // Would be nice to handle OBJECT and APPLET tags,
               // but that gets more complicated since we have to
               // search the tag list for CODEBASE as well.
diff --git a/parser/htmlparser/src/nsViewSourceHTML.cpp b/parser/htmlparser/src/nsViewSourceHTML.cpp
index 9e7baa2b6bf..a281af4f712 100644
--- a/parser/htmlparser/src/nsViewSourceHTML.cpp
+++ b/parser/htmlparser/src/nsViewSourceHTML.cpp
@@ -1203,7 +1203,7 @@ NS_IMETHODIMP CViewSourceHTML::HandleToken(CToken* aToken,nsIParser* aParser) {
       {
         nsAutoString theStr;
         theStr.Assign(aToken->GetStringValue());
-        if(!theStr.Equals(NS_LITERAL_STRING("XI"), nsCaseInsensitiveStringComparator())) {
+        if(Compare(theStr, NS_LITERAL_STRING("XI"), nsCaseInsensitiveStringComparator()) != 0) {
           PRUnichar theChar=theStr.CharAt(0);
           if((nsCRT::IsAsciiDigit(theChar)) || ('X'==theChar) || ('x'==theChar)){
             theStr.Assign(NS_LITERAL_STRING("#") + theStr);
diff --git a/rdf/base/src/rdfutil.cpp b/rdf/base/src/rdfutil.cpp
index 07183c75287..3aa9b5d85aa 100644
--- a/rdf/base/src/rdfutil.cpp
+++ b/rdf/base/src/rdfutil.cpp
@@ -92,8 +92,8 @@ rdf_RequiresAbsoluteURI(const nsString& uri)
     // cheap shot at figuring out if this requires an absolute url translation
     if (Substring(uri, 0, 4).Equals(NS_LITERAL_STRING("urn:")) ||
         Substring(uri, 0, 9).Equals(NS_LITERAL_STRING("chrome:")) ||
-        Substring(uri, 0, 3).Equals(NS_LITERAL_STRING("nc:"),
-                                    nsCaseInsensitiveStringComparator())) {
+        !Compare(Substring(uri, 0, 3), NS_LITERAL_STRING("nc:"),
+                 nsCaseInsensitiveStringComparator())) {
         return PR_FALSE;
      }
      return PR_TRUE;
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index a7160cc8884..28f2afd1203 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -1744,8 +1744,9 @@ nsresult nsExternalHelperAppService::GetMIMEInfoForExtensionFromExtras(const cha
       while (start != end)
       {
           FindCharInReadable(',', iter, end);
-          if (Substring(start, iter).Equals(extension,
-                                            nsCaseInsensitiveCStringComparator()))
+          if (Compare(Substring(start, iter),
+                      extension,
+                      nsCaseInsensitiveCStringComparator()) == 0)
           {
               // This is the one.  Create MIMEInfo object and set
               // attributes appropriately.
diff --git a/uriloader/exthandler/unix/nsOSHelperAppService.cpp b/uriloader/exthandler/unix/nsOSHelperAppService.cpp
index 7cf6f53a51f..01ba227d643 100644
--- a/uriloader/exthandler/unix/nsOSHelperAppService.cpp
+++ b/uriloader/exthandler/unix/nsOSHelperAppService.cpp
@@ -442,8 +442,9 @@ GetTypeAndDescriptionFromMimetypesFile(const nsAString& aFilename,
 
           while (start != end) {
             FindCharInReadable(',', iter, end);
-            if (Substring(start, iter).Equals(aFileExtension,
-                                              nsCaseInsensitiveStringComparator())) {
+            if (Compare(Substring(start, iter),
+                        aFileExtension,
+                        nsCaseInsensitiveStringComparator()) == 0) {
               // it's a match.  Assign the type and description and run
               aMajorType.Assign(Substring(majorTypeStart, majorTypeEnd));
               aMinorType.Assign(Substring(minorTypeStart, minorTypeEnd));
@@ -573,12 +574,12 @@ GetExtensionsAndDescriptionFromMimetypesFile(const nsAString& aFilename,
         }
 #endif
         if (NS_SUCCEEDED(rv) &&
-            Substring(majorTypeStart,
-                      majorTypeEnd).Equals(aMajorType,
-                                           nsCaseInsensitiveStringComparator())&&
-            Substring(minorTypeStart,
-                      minorTypeEnd).Equals(aMinorType,
-                                           nsCaseInsensitiveStringComparator())) {
+            Compare(Substring(majorTypeStart, majorTypeEnd),
+                    aMajorType,
+                    nsCaseInsensitiveStringComparator()) == 0 &&
+            Compare(Substring(minorTypeStart, minorTypeEnd),
+                    aMinorType,
+                    nsCaseInsensitiveStringComparator()) == 0) {
           // it's a match
           aFileExtensions.Assign(extensions);
           aDescription.Assign(Substring(descriptionStart, descriptionEnd));
@@ -947,14 +948,13 @@ GetHandlerAndDescriptionFromMailcapFile(const nsAString& aFilename,
           rv = ParseMIMEType(start_iter, majorTypeStart, majorTypeEnd,
                              minorTypeStart, minorTypeEnd, semicolon_iter);
           if (NS_SUCCEEDED(rv) &&
-              Substring(majorTypeStart,
-                        majorTypeEnd).Equals(aMajorType,
-                                             nsCaseInsensitiveStringComparator()) &&
-              (Substring(minorTypeStart,
-                         minorTypeEnd).Equals(NS_LITERAL_STRING("*")) ||
-               Substring(minorTypeStart,
-                         minorTypeEnd).Equals(aMinorType,
-                                              nsCaseInsensitiveStringComparator()))) { // we have a match
+              Compare(Substring(majorTypeStart, majorTypeEnd),
+                      aMajorType,
+                      nsCaseInsensitiveStringComparator()) == 0 &&
+              (Substring(minorTypeStart, minorTypeEnd).Equals(NS_LITERAL_STRING("*")) ||
+               Compare(Substring(minorTypeStart, minorTypeEnd),
+                       aMinorType,
+                       nsCaseInsensitiveStringComparator()) == 0)) { // we have a match
             PRBool match = PR_TRUE;
             ++semicolon_iter;             // point at the first char past the semicolon
             start_iter = semicolon_iter;  // handler string starts here
diff --git a/xpfe/components/bookmarks/src/nsBookmarksService.cpp b/xpfe/components/bookmarks/src/nsBookmarksService.cpp
index ce3c067a751..5799f6f5938 100644
--- a/xpfe/components/bookmarks/src/nsBookmarksService.cpp
+++ b/xpfe/components/bookmarks/src/nsBookmarksService.cpp
@@ -934,22 +934,27 @@ BookmarkParser::Unescape(nsString &text)
 
 	while((offset = text.FindChar((PRUnichar('&')), offset)) >= 0)
 	{
-		if (Substring(text, offset, 4).Equals(NS_LITERAL_STRING("&lt;"), nsCaseInsensitiveStringComparator()))
+		// XXX get max of 6 chars; change the value below if
+		// we ever start looking for longer HTML-escaped values
+		nsAutoString	temp;
+		text.Mid(temp, offset, 6);
+
+		if (Compare(Substring(temp, 0, 4), NS_LITERAL_STRING("&lt;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 4);
 			text.Insert(PRUnichar('<'), offset);
 		}
-		else if (Substring(text, offset, 4).Equals(NS_LITERAL_STRING("&gt;"), nsCaseInsensitiveStringComparator()))
+		if (Compare(Substring(temp, 0, 4), NS_LITERAL_STRING("&gt;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 4);
 			text.Insert(PRUnichar('>'), offset);
 		}
-		else if (Substring(text, offset, 5).Equals(NS_LITERAL_STRING("&amp;"), nsCaseInsensitiveStringComparator()))
+		if (Compare(Substring(temp, 0, 5), NS_LITERAL_STRING("&amp;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 5);
 			text.Insert(PRUnichar('&'), offset);
 		}
-		else if (Substring(text, offset, 6).Equals(NS_LITERAL_STRING("&quot;"), nsCaseInsensitiveStringComparator()))
+		if (Compare(Substring(temp, 0, 6), NS_LITERAL_STRING("&quot;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 6);
 			text.Insert(PRUnichar('\"'), offset);
diff --git a/xpfe/components/related/src/nsRelatedLinksHandler.cpp b/xpfe/components/related/src/nsRelatedLinksHandler.cpp
index 8ee62965506..0dfcebb42e2 100644
--- a/xpfe/components/related/src/nsRelatedLinksHandler.cpp
+++ b/xpfe/components/related/src/nsRelatedLinksHandler.cpp
@@ -556,22 +556,27 @@ RelatedLinksStreamListener::Unescape(nsString &text)
 
 	while((offset = text.FindChar((PRUnichar('&')), offset)) >= 0)
 	{
-		if (Substring(text, offset, 4).Equals(NS_LITERAL_STRING("&lt;"), nsCaseInsensitiveStringComparator()))
+		// XXX get max of 6 chars; change the value below if
+		// we ever start looking for longer HTML-escaped values
+		nsAutoString	temp;
+		text.Mid(temp, offset, 6);
+
+		if (Compare(Substring(temp, 0, 4), NS_LITERAL_STRING("&lt;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 4);
 			text.Insert(PRUnichar('<'), offset);
 		}
-		else if (Substring(text, offset, 4).Equals(NS_LITERAL_STRING("&gt;"), nsCaseInsensitiveStringComparator()))
+		if (Compare(Substring(temp, 0, 4), NS_LITERAL_STRING("&gt;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 4);
 			text.Insert(PRUnichar('>'), offset);
 		}
-		else if (Substring(text, offset, 5).Equals(NS_LITERAL_STRING("&amp;"), nsCaseInsensitiveStringComparator()))
+		if (Compare(Substring(temp, 0, 5), NS_LITERAL_STRING("&amp;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 5);
 			text.Insert(PRUnichar('&'), offset);
 		}
-		else if (Substring(text, offset, 6).Equals(NS_LITERAL_STRING("&quot;"), nsCaseInsensitiveStringComparator()))
+		if (Compare(Substring(temp, 0, 6), NS_LITERAL_STRING("&quot;"), nsCaseInsensitiveStringComparator()) == 0)
 		{
 			text.Cut(offset, 6);
 			text.Insert(PRUnichar('\"'), offset);
diff --git a/xpfe/components/urlbarhistory/src/nsUrlbarHistory.cpp b/xpfe/components/urlbarhistory/src/nsUrlbarHistory.cpp
index 27241dd143b..828061499e4 100644
--- a/xpfe/components/urlbarhistory/src/nsUrlbarHistory.cpp
+++ b/xpfe/components/urlbarhistory/src/nsUrlbarHistory.cpp
@@ -337,9 +337,9 @@ nsUrlbarHistory::SearchPreviousResults(const PRUnichar *searchStr, nsIAutoComple
     // which doesn't make any sense (since the "!= 0" was inside the
     // parentheses)
     if (searchStrLen < prevSearchStrLen ||
-        !Substring(searchStr,
-                   searchStr+prevSearchStrLen).Equals(nsDependentString(prevSearchString, prevSearchStrLen),
-                                                      nsCaseInsensitiveStringComparator()))
+        Compare(Substring(searchStr, searchStr+prevSearchStrLen),
+                nsDependentString(prevSearchString, prevSearchStrLen),
+                nsCaseInsensitiveStringComparator())!= 0)
         return NS_ERROR_ABORT;
 
     nsCOMPtr<nsISupportsArray> array;
@@ -368,9 +368,9 @@ nsUrlbarHistory::SearchPreviousResults(const PRUnichar *searchStr, nsIAutoComple
 
 			if (itemValue.IsEmpty())
 				continue;
-            if (nsDependentString(searchStr,
-                                  searchStrLen).Equals(Substring(itemValue, 0, searchStrLen),
-                                                       nsCaseInsensitiveStringComparator()))
+            if (Compare(nsDependentString(searchStr, searchStrLen),
+                        Substring(itemValue, 0, searchStrLen),
+                        nsCaseInsensitiveStringComparator()) == 0)
                 continue;
 
 	    }
@@ -626,8 +626,8 @@ nsUrlbarHistory::CheckItemAvailability(const PRUnichar * aItem, nsIAutoCompleteR
             resultItem->GetValue(itemValue);
             // Using nsIURI to do comparisons didn't quite work out.
             // So use nsCRT methods
-            if (itemValue.Equals(nsDependentString(aItem),
-                                 nsCaseInsensitiveStringComparator()))
+            if (Compare(itemValue, nsDependentString(aItem),
+                        nsCaseInsensitiveStringComparator()) == 0)
             {
                 //printf("In CheckItemAvailability. Item already found\n");
                 *aResult = PR_TRUE;