Adding a new string class for to help fix performance problems.

xpcom/ds/nsWorkString.cpp

@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * The contents of this file are subject to the Netscape Public
+ * License Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the License is distributed on an "AS
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 2000 Netscape Communications Corporation. All
+ * Rights Reserved.
+ *
+ * Original Author:
+ *   Scott Collins <scc@mozilla.org>
+ *
+ * Contributor(s):
+ */
+
+#include "nsWorkString.h"
+
+void
+nsWorkString::SetLength( PRUint32 aNewLength )
+  {
+    if ( aNewLength > mCapacity )
+      {
+        PRUint32 newCapacity = mCapacity ? mCapacity : kInitialWorkStringCapacity;
+        while ( newCapacity < aNewLength )
+          newCapacity += newCapacity;
+        SetCapacity(newCapacity);
+      }
+    inherited::SetLength(aNewLength);
+  }
+
+void
+nsWorkCString::SetLength( PRUint32 aNewLength )
+  {
+    if ( aNewLength > mCapacity )
+      {
+        PRUint32 newCapacity = mCapacity ? mCapacity : kInitialWorkCStringCapacity;
+        while ( newCapacity < aNewLength )
+          newCapacity += newCapacity;
+        SetCapacity(newCapacity);
+      }
+    inherited::SetLength(aNewLength);
+  }

xpcom/ds/nsWorkString.h

@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * The contents of this file are subject to the Netscape Public
+ * License Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the License is distributed on an "AS
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 2000 Netscape Communications Corporation. All
+ * Rights Reserved.
+ *
+ * Original Author:
+ *   Scott Collins <scc@mozilla.org>
+ *
+ * Contributor(s):
+ */
+
+#ifndef nsWorkString_h___
+#define nsWorkString_h___
+
+#include "nsString.h"
+
+
+  /*
+    The following two classes could be based on |nsAutoString| and
+    |nsCAutoString|, respectively.  The decision should be made based
+    on profiling.
+  */
+
+class NS_COM nsWorkString : public nsString
+  {
+    private:
+      typedef nsString inherited;
+
+    public:
+      static const PRUint32 kInitialWorkStringCapacity = 32;
+
+      nsWorkString() : inherited() { }
+      nsWorkString( const nsAReadableString& aReadable ) : inherited(aReadable) { }
+      nsWorkString( const PRUnichar* aString, PRUint32 aLength ) : inherited(aString, PRInt32(aLength)) { }
+      nsWorkString( const PRUnichar* aString ) : inherited(aString) { }
+      
+      virtual void SetLength( PRUint32 aNewLength );
+  };
+
+class NS_COM nsWorkCString : public nsCString
+  {
+    private:
+      typedef nsCString inherited;
+
+    public:
+      static const PRUint32 kInitialWorkCStringCapacity = 32;
+
+      nsWorkCString() : inherited() { }
+      nsWorkCString( const nsAReadableCString& aReadable ) : inherited(aReadable) { }
+      nsWorkCString( const char* aString, PRUint32 aLength ) : inherited(aString, PRInt32(aLength)) { }
+      nsWorkCString( const char* aString ) : inherited(aString) { }
+      
+      virtual void SetLength( PRUint32 aNewLength );
+  };
+
+#endif // !defined(nsWorkString_h___)