Bug 692145 Separate CountNewlinesIn() to CountNewlinesInXPLength() and CountNewlinesInNativeLength() r=ehsan

content/events/src/nsContentEventHandler.cpp

@@ -207,16 +207,17 @@ static void AppendSubString(nsAString& aString, nsIContent* aContent,
 }
 
 #if defined(XP_WIN)
-static PRUint32 CountNewlinesIn(nsIContent* aContent, PRUint32 aMaxOffset)
+static PRUint32 CountNewlinesInXPLength(nsIContent* aContent,
+                                        PRUint32 aXPLength)
 {
   NS_ASSERTION(aContent->IsNodeOfType(nsINode::eTEXT),
                "aContent is not a text node!");
   const nsTextFragment* text = aContent->GetText();
   if (!text)
     return 0;
-  NS_ASSERTION(aMaxOffset == PR_UINT32_MAX || aMaxOffset <= text->GetLength(),
+  NS_ASSERTION(aXPLength == PR_UINT32_MAX || aXPLength <= text->GetLength(),
                "text offset is out-of-bounds");
-  const PRUint32 length = NS_MIN(aMaxOffset, text->GetLength());
+  const PRUint32 length = NS_MIN(aXPLength, text->GetLength());
   PRUint32 newlines = 0;
   for (PRUint32 i = 0; i < length; ++i) {
     if (text->CharAt(i) == '\n') {
@@ -225,6 +226,28 @@ static PRUint32 CountNewlinesIn(nsIContent* aContent, PRUint32 aMaxOffset)
   }
   return newlines;
 }
+
+static PRUint32 CountNewlinesInNativeLength(nsIContent* aContent,
+                                            PRUint32 aNativeLength)
+{
+  NS_ASSERTION(aContent->IsNodeOfType(nsINode::eTEXT),
+               "aContent is not a text node!");
+  const nsTextFragment* text = aContent->GetText();
+  if (!text) {
+    return 0;
+  }
+  const PRUint32 xpLength = text->GetLength();
+  PRUint32 newlines = 0;
+  for (PRUint32 i = 0, nativeOffset = 0;
+       i < xpLength && nativeOffset < aNativeLength;
+       ++i, ++nativeOffset) {
+    if (text->CharAt(i) == '\n') {
+      ++newlines;
+      ++nativeOffset;
+    }
+  }
+  return newlines;
+}
 #endif
 
 static PRUint32 GetNativeTextLength(nsIContent* aContent, PRUint32 aMaxLength = PR_UINT32_MAX)
@@ -239,7 +262,7 @@ static PRUint32 GetNativeTextLength(nsIContent* aContent, PRUint32 aMaxLength =
       // On Windows, the length of a native newline ("\r\n") is twice the length of
       // the XP newline ("\n"), so XP length is equal to the length of the native
       // offset plus the number of newlines encountered in the string.
-      CountNewlinesIn(aContent, aMaxLength);
+      CountNewlinesInXPLength(aContent, aMaxLength);
 #else
       // On other platforms, the native and XP newlines are the same.
       0;
@@ -271,7 +294,7 @@ static PRUint32 ConvertToXPOffset(nsIContent* aContent, PRUint32 aNativeOffset)
   // On Windows, the length of a native newline ("\r\n") is twice the length of
   // the XP newline ("\n"), so XP offset is equal to the length of the native
   // offset minus the number of newlines encountered in the string.
-  return aNativeOffset - CountNewlinesIn(aContent, aNativeOffset);
+  return aNativeOffset - CountNewlinesInNativeLength(aContent, aNativeOffset);
 #else
   // On other platforms, the native and XP newlines are the same.
   return aNativeOffset;