Print Preview: Go from event driven print preview back to print preview with sync messages. The s...

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 66 matching lines @@
 
   return tab_controller->GetPrintPreviewForTab(tab_contents());
 }
 
 void PrintPreviewMessageHandler::OnRequestPrintPreview() {
   PrintPreviewTabController::PrintPreview(tab_contents());
 }
 
 void PrintPreviewMessageHandler::OnDidGetPreviewPageCount(
     const PrintHostMsg_DidGetPreviewPageCount_Params& params) {
-  if (params.page_count <= 0)
+  if (params.page_count <= 0) {
+    NOTREACHED();
     return;
+  }
 
   TabContents* print_preview_tab = GetPrintPreviewTab();
   if (!print_preview_tab || !print_preview_tab->web_ui())
     return;
 
   PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
   print_preview_ui->OnDidGetPreviewPageCount(params);
 }
 
 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()) {
-    // Can't find print preview tab means we should abort.
-    rvh->Send(new PrintMsg_AbortPreview(rvh->routing_id()));
+  if (!print_preview_tab || !print_preview_tab->web_ui())
     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 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();
 
   if (page_number >= FIRST_PAGE_INDEX && params.data_size) {
     RefCountedBytes* data_bytes =
         GetDataFromHandle(params.metafile_data_handle, params.data_size);
     DCHECK(data_bytes);
 
     print_preview_ui->SetPrintPreviewDataForIndex(page_number, data_bytes);
     print_preview_ui->OnDidPreviewPage(page_number, params.preview_request_id);
-    // TODO(kmadhusu): Query |PrintPreviewUI| and update
-    // |requested_preview_page_index| accordingly.
   }
-
-  rvh->Send(new PrintMsg_ContinuePreview(rvh->routing_id(),
-                                         requested_preview_page_index));
 }
 
 void PrintPreviewMessageHandler::OnPagesReadyForPreview(
     const PrintHostMsg_DidPreviewDocument_Params& params) {
+  if (params.expected_pages_count <= 0) {
+    NOTREACHED();
+    return;
+  }
   StopWorker(params.document_cookie);

[kmadhusu, 2011/08/22 21:23:57]

Is it better to stop the worker before validating any params values?

[Lei Zhang, 2011/08/22 22:26:55]

Sure. Why not.

 
   // Get the print preview tab.
   TabContents* print_preview_tab = GetPrintPreviewTab();
   // User might have closed it already.
   if (!print_preview_tab)
     return;
 
   PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
 
@@ skipping 45 matching lines @@
           HasTabContents(wrapper)) {
     // Preview tab was hidden to serve the print request.
     delete wrapper;
   } else {
     PrintPreviewUI* print_preview_ui =
       static_cast<PrintPreviewUI*>(print_preview_tab->web_ui());
     print_preview_ui->OnPrintPreviewFailed();
   }
 }
 
+void PrintPreviewMessageHandler::OnPrintPreviewCancelled(int document_cookie) {
+  // Always need to stop the worker.
+  StopWorker(document_cookie);
+}
+
 bool PrintPreviewMessageHandler::OnMessageReceived(
     const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PrintPreviewMessageHandler, message)
     IPC_MESSAGE_HANDLER(PrintHostMsg_RequestPrintPreview,
                         OnRequestPrintPreview)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidGetPreviewPageCount,
                         OnDidGetPreviewPageCount)
     IPC_MESSAGE_HANDLER(PrintHostMsg_DidPreviewPage,
                         OnDidPreviewPage)
     IPC_MESSAGE_HANDLER(PrintHostMsg_PagesReadyForPreview,
                         OnPagesReadyForPreview)
     IPC_MESSAGE_HANDLER(PrintHostMsg_PrintPreviewFailed,
                         OnPrintPreviewFailed)
+    IPC_MESSAGE_HANDLER(PrintHostMsg_PrintPreviewCancelled,
+                        OnPrintPreviewCancelled)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void PrintPreviewMessageHandler::DidStartLoading() {
   if (tab_contents()->delegate() &&
       printing::PrintPreviewTabController::IsPrintPreviewTab(tab_contents())) {
     tab_contents()->SetContentRestrictions(CONTENT_RESTRICTION_PRINT);
   }
 }
 
 }  // namespace printing