diff --git a/xpinstall/src/nsInstall.cpp b/xpinstall/src/nsInstall.cpp
index a28bf9afdf2..56683b774f3 100644
--- a/xpinstall/src/nsInstall.cpp
+++ b/xpinstall/src/nsInstall.cpp
@@ -1973,6 +1973,63 @@ nsInstall::FileOpFileRename(nsInstallFolder& aSrc, nsString& aTarget, PRInt32* a
   return NS_OK;
 }
 
+#ifdef _WINDOWS
+#include <winbase.h>
+#endif
+
+
+PRInt32
+nsInstall::FileOpFileWindowsGetShortName(nsInstallFolder& aTarget, nsString& aShortPathName)
+{
+#ifdef _WINDOWS
+
+  PRInt32             err;
+  PRBool              flagExists;
+  nsString            tmpNsString;
+  nsXPIDLCString      nativeTargetPath;
+  char                nativeShortPathName[MAX_PATH];
+  nsCOMPtr<nsIFile>   localTarget(aTarget.GetFileSpec());
+
+  if(localTarget == nsnull)
+    return NS_OK;
+
+  localTarget->Exists(&flagExists);
+  if(flagExists)
+  {
+    memset(nativeShortPathName, 0, MAX_PATH);
+    localTarget->GetPath(getter_Copies(nativeTargetPath));
+
+    err = GetShortPathName(nativeTargetPath, nativeShortPathName, MAX_PATH);
+    if((err > 0) && (*nativeShortPathName == '\0'))
+    {
+      // NativeShortPathName buffer not big enough.
+      // Reallocate and try again.
+      // err will have the required size.
+      char *nativeShortPathNameTmp = new char[err + 1];
+      if(nativeShortPathNameTmp == nsnull)
+        return NS_OK;
+
+      err = GetShortPathName(nativeTargetPath, nativeShortPathNameTmp, err + 1);
+      // Is it safe to assume that the second time around the buffer is big enough
+      // and not to worry about it unless it's a different problem?
+
+      // if err is 0, it's not a buffer size problem.  It's something else unexpected.
+      if(err != 0)
+        aShortPathName.AssignWithConversion(nativeShortPathNameTmp);
+
+      if(nativeShortPathNameTmp)
+        delete [] nativeShortPathNameTmp;
+    }
+    else if(err != 0)
+      // if err is 0, it's not a buffer size problem.  It's something else unexpected.
+      aShortPathName.AssignWithConversion(nativeShortPathName);
+  }
+
+#endif
+
+  return NS_OK;
+}
+
 PRInt32
 nsInstall::FileOpFileWindowsShortcut(nsIFile* aTarget, nsIFile* aShortcutPath, nsString& aDescription, nsIFile* aWorkingPath, nsString& aParams, nsIFile* aIcon, PRInt32 aIconId, PRInt32* aReturn)
 {
diff --git a/xpinstall/src/nsInstall.h b/xpinstall/src/nsInstall.h
index 5820c437475..9e4b02676c6 100644
--- a/xpinstall/src/nsInstall.h
+++ b/xpinstall/src/nsInstall.h
@@ -252,6 +252,7 @@ class nsInstall
         PRInt32    FileOpFileModDateChanged(nsInstallFolder& aTarget, double aOldStamp, PRBool* aReturn);
         PRInt32    FileOpFileMove(nsInstallFolder& aSrc, nsInstallFolder& aTarget, PRInt32* aReturn);
         PRInt32    FileOpFileRename(nsInstallFolder& aSrc, nsString& aTarget, PRInt32* aReturn);
+        PRInt32    FileOpFileWindowsGetShortName(nsInstallFolder& aTarget, nsString& aShortPathName);
         PRInt32    FileOpFileWindowsShortcut(nsIFile* aTarget, nsIFile* aShortcutPath, nsString& aDescription, nsIFile* aWorkingPath, nsString& aParams, nsIFile* aIcon, PRInt32 aIconId, PRInt32* aReturn);
         PRInt32    FileOpFileMacAlias(nsIFile *aSourceFile, nsIFile *aAliasFile, PRInt32* aReturn);
         PRInt32    FileOpFileUnixLink(nsInstallFolder& aTarget, PRInt32 aFlags, PRInt32* aReturn);
diff --git a/xpinstall/src/nsJSFile.cpp b/xpinstall/src/nsJSFile.cpp
index 9ede072e9af..ac9697d6716 100644
--- a/xpinstall/src/nsJSFile.cpp
+++ b/xpinstall/src/nsJSFile.cpp
@@ -991,6 +991,54 @@ InstallFileOpFileRename(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, j
   return JS_TRUE;
 }
 
+//
+// Native method FileWindowsGetShortName
+//
+JSBool PR_CALLBACK
+InstallFileOpFileWindowsGetShortName(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
+{
+  nsAutoString shortPathName;
+  nsInstall*   nativeThis = (nsInstall*)JS_GetPrivate(cx, obj);
+  JSObject *jsObj;
+  nsInstallFolder *longPathName;
+
+  *rval = JSVAL_NULL;
+
+  // If there's no private data, this must be the prototype, so ignore
+  if(nsnull == nativeThis)
+  {
+    return JS_TRUE;
+  }
+
+  //  public String windowsGetShortName (File NativeFolderPath);
+
+  if ( argc == 0 || argv[0] == JSVAL_NULL || !JSVAL_IS_OBJECT(argv[0])) //argv[0] MUST be a jsval
+  {
+    // error, return NULL
+    return JS_TRUE;
+  }
+
+  jsObj = JSVAL_TO_OBJECT(argv[0]);
+
+  if (!JS_InstanceOf(cx, jsObj, &FileSpecObjectClass, nsnull))
+  {
+    // error, return NULL
+    return JS_TRUE;
+  }
+
+  longPathName = (nsInstallFolder*)JS_GetPrivate(cx, jsObj);
+
+  if(!longPathName || NS_OK != nativeThis->FileOpFileWindowsGetShortName(*longPathName, shortPathName))
+  {
+    return JS_TRUE;
+  }
+
+  if(shortPathName.Length() != 0)
+    *rval = STRING_TO_JSVAL(JS_NewUCStringCopyN(cx, NS_STATIC_CAST(const jschar*, shortPathName.GetUnicode()), shortPathName.Length()));
+
+  return JS_TRUE;
+}
+
 //
 // Native method FileWindowsShortcut
 //
@@ -1362,6 +1410,7 @@ static JSFunctionSpec FileOpMethods[] =
   {"modDateChanged",            InstallFileOpFileModDateChanged,       2},
   {"move",                      InstallFileOpFileMove,                 2},
   {"rename",                    InstallFileOpFileRename,               2},
+  {"windowsGetShortName",       InstallFileOpFileWindowsGetShortName,  1},
   {"windowsShortcut",           InstallFileOpFileWindowsShortcut,      7},
   {"macAlias",                  InstallFileOpFileMacAlias,             2},
   {"unixLink",                  InstallFileOpFileUnixLink,             2},