Print Preview: Handle a crashed initiator tab by showing a message in PP.

chrome/browser/printing/print_preview_message_handler.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/printing/print_preview_message_handler.h"
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/ref_counted_memory.h"
@@ skipping 30 matching lines @@
 }
 
 RefCountedBytes* GetDataFromHandle(base::SharedMemoryHandle handle,
                                    uint32 data_size) {
   scoped_ptr<base::SharedMemory> shared_buf(
       new base::SharedMemory(handle, true));
   if (!shared_buf->Map(data_size)) {
     NOTREACHED();
     return NULL;
   }
+
   char* preview_data = static_cast<char*>(shared_buf->memory());
   std::vector<unsigned char> data(data_size);
   memcpy(&data[0], preview_data, data_size);
   return RefCountedBytes::TakeVector(&data);
 }
 
 }  // namespace
 
 namespace printing {
 
 PrintPreviewMessageHandler::PrintPreviewMessageHandler(
     TabContents* tab_contents)
     : TabContentsObserver(tab_contents) {
   DCHECK(tab_contents);
 }
 
 PrintPreviewMessageHandler::~PrintPreviewMessageHandler() {
 }
 
 TabContents* PrintPreviewMessageHandler::GetPrintPreviewTab() {
   // Get/Create preview tab for initiator tab.
   printing::PrintPreviewTabController* tab_controller =
       printing::PrintPreviewTabController::GetInstance();
   if (!tab_controller)
     return NULL;
+
   return tab_controller->GetPrintPreviewForTab(tab_contents());
 }
 
 void PrintPreviewMessageHandler::OnRequestPrintPreview() {
   PrintPreviewTabController::PrintPreview(tab_contents());
 }
 
 void PrintPreviewMessageHandler::OnDidGetPreviewPageCount(int document_cookie,
                                                           int page_count,
                                                           bool is_modifiable) {
   if (page_count <= 0)
     return;
+
   TabContents* print_preview_tab = GetPrintPreviewTab();
-  if (!print_preview_tab)
+  if (!print_preview_tab || !print_preview_tab->web_ui())

[Lei Zhang, 2011/08/09 20:51:19]

Everything in this file can go into the cleanup CL as well.

[kmadhusu, 2011/08/10 16:46:59]

Done.

     return;
 
   PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
   print_preview_ui->OnDidGetPreviewPageCount(
       document_cookie, page_count, is_modifiable);
 }
 
 void PrintPreviewMessageHandler::OnDidPreviewPage(
     const PrintHostMsg_DidPreviewPage_Params& params) {
   RenderViewHost* rvh = tab_contents()->render_view_host();
   TabContents* print_preview_tab = GetPrintPreviewTab();
-  if (!(print_preview_tab && print_preview_tab->web_ui())) {
+  if (!print_preview_tab || !print_preview_tab->web_ui()) {
     // Can't find print preview tab means we should abort.
     rvh->Send(new PrintMsg_AbortPreview(rvh->routing_id()));
     return;
   }
 
   PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
   bool has_pending = print_preview_ui->HasPendingRequests();
   if (has_pending) {
-    // Cancel. Next print preview request will cancel the current one.
-    // Just do the required maintainance work here.
+    // Cancel. Next print preview request will cancel the current one. Just do
+    // the required maintenance work here.
     StopWorker(print_preview_ui->document_cookie());
     print_preview_ui->OnPrintPreviewCancelled();
     return;
   }
 
   int requested_preview_page_index = INVALID_PAGE_INDEX;
   int page_number = params.page_number;
 
   if (page_number == FIRST_PAGE_INDEX)
     print_preview_ui->ClearAllPreviewData();
@@ skipping 101 matching lines @@
 }
 
 void PrintPreviewMessageHandler::DidStartLoading() {
   if (tab_contents()->delegate() &&
       printing::PrintPreviewTabController::IsPrintPreviewTab(tab_contents())) {
     tab_contents()->SetContentRestrictions(CONTENT_RESTRICTION_PRINT);
   }
 }
 
 }  // namespace printing