Bug 407080: Disallow print-preview if page is loading. r+sr=roc, a=blocking1.9+

layout/printing/nsPrintEngine.cpp

@@ -729,6 +729,20 @@ nsPrintEngine::PrintPreview(nsIPrintSettings* aPrintSettings,
                                  nsIDOMWindow *aChildDOMWin, 
                                  nsIWebProgressListener* aWebProgressListener)
 {
+  // Get the DocShell and see if it is busy
+  // (We can't Print Preview this document if it is still busy)
+  nsCOMPtr<nsIDocShell> docShell(do_QueryInterface(mContainer));
+  NS_ASSERTION(docShell, "This has to be a docshell");
+
+  PRUint32 busyFlags = nsIDocShell::BUSY_FLAGS_NONE;
+  if (NS_FAILED(docShell->GetBusyFlags(&busyFlags)) ||
+      busyFlags != nsIDocShell::BUSY_FLAGS_NONE) {
+    CloseProgressDialog(aWebProgressListener);
+    ShowPrintErrorDialog(NS_ERROR_GFX_PRINTER_DOC_IS_BUSY_PP, PR_FALSE);
+    return NS_ERROR_FAILURE;
+  }
+
+  // Document is not busy -- go ahead with the Print Preview
   return CommonPrint(PR_TRUE, aPrintSettings, aWebProgressListener);
 }