Implement print preview tab controller.

chrome/browser/printing/print_preview_tab_controller.cc

+// Copyright (c) 2010 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_tab_controller.h"
+
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/tab_contents/tab_contents.h"
+#include "chrome/browser/tabs/tab_strip_model.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/browser_navigator.h"
+#include "chrome/common/notification_service.h"
+#include "chrome/common/url_constants.h"
+
+namespace printing {
+
+// static
+PrintPreviewTabController* PrintPreviewTabController::GetInstance() {
+  if (!g_browser_process)
+    return NULL;
+  return g_browser_process->print_preview_tab_controller();
+}
+
+PrintPreviewTabController::PrintPreviewTabController()
+    : waiting_for_new_preview_page_(false) {
+}
+
+PrintPreviewTabController::~PrintPreviewTabController() {
+  preview_tab_map_.clear();
+}
+
+TabContents* PrintPreviewTabController::GetOrCreatePreviewTab(
+    TabContents* current_tab, int browser_window_id ) {

[Lei Zhang, 2010/11/12 23:17:18]

nit: |current_tab| should be named "initiator_tab" to match the prototype.

[kmadhusu, 2010/11/13 00:05:59]

Done.

+  // Initiator tab is a preview tab.
+  if (IsPrintPreviewTab(current_tab))
+    return current_tab;
+
+  // Get the preview tab for initiator tab.
+  TabContents* preview_tab = GetPreviewTab(current_tab);
+  if (preview_tab) {
+    // Show current preview tab.
+    preview_tab->Activate();
+    return preview_tab;
+  }
+  return CreatePrintPreviewTab(current_tab, browser_window_id);
+}
+
+bool PrintPreviewTabController::IsPrintPreviewTab(TabContents* tab) {
+  const GURL& url = tab->GetURL();
+  if (url.SchemeIs(chrome::kChromeUIScheme) &&
+      url.host() == chrome::kChromeUIPrintHost)
+    return true;
+
+  TabContents* preview_tab = GetPreviewTab(tab);
+  return ((preview_tab)? (preview_tab == tab) : false);
+}
+
+Browser* PrintPreviewTabController::GetBrowserWindow(int browser_window_id) {
+  return BrowserList::FindBrowserWithID(browser_window_id);
+}
+
+TabContents* PrintPreviewTabController::GetInitiatorTab(
+    TabContents* preview_tab) {
+  PrintPreviewTabMap::iterator it = preview_tab_map_.find(preview_tab);
+  if (it != preview_tab_map_.end())
+    return preview_tab_map_[preview_tab];
+  return NULL;
+}
+
+TabContents* PrintPreviewTabController::GetPreviewTab(
+    TabContents* current_tab) {
+  for (PrintPreviewTabMap::iterator it = preview_tab_map_.begin();
+       it != preview_tab_map_.end(); ++it) {
+    if ((it->second == current_tab) || (it->first == current_tab))
+      return it->first;
+  }
+  return NULL;
+}
+
+void PrintPreviewTabController::AddObservers(TabContents* tab) {
+  // Add TAB_CONTENTS_DESTROYED notification.

[Lei Zhang, 2010/11/12 23:48:40]

nit: the comments in {Add,Remove}Observers are not useful.

[kmadhusu, 2010/11/13 00:05:59]

Done.

+  registrar_.Add(this, NotificationType::TAB_CONTENTS_DESTROYED,
+                 Source<TabContents>(tab));
+
+  // Add NAV_ENTRY_COMMITTED notification.
+  registrar_.Add(this, NotificationType::NAV_ENTRY_COMMITTED,
+                 Source<NavigationController>(&tab->controller()));
+}
+
+void PrintPreviewTabController::RemoveObservers(TabContents* tab) {
+  // Remove TAB_CONTENTS_DESTROYED notification.
+  registrar_.Remove(this, NotificationType::TAB_CONTENTS_DESTROYED,
+                    Source<TabContents>(tab));
+
+  // Remove NAV_ENTRY_COMMITTED notification.
+  registrar_.Remove(this, NotificationType::NAV_ENTRY_COMMITTED,
+                    Source<NavigationController>(&tab->controller()));
+}
+
+TabContents* PrintPreviewTabController::CreatePrintPreviewTab(
+    TabContents* initiator_tab, int browser_window_id) {
+  Browser* current_browser = GetBrowserWindow(browser_window_id);
+  // Add a new tab next to initiator tab.
+  browser::NavigateParams params(current_browser,
+                                 GURL(chrome::kChromeUIPrintURL),
+                                 PageTransition::LINK);
+  params.disposition = NEW_FOREGROUND_TAB;
+  params.tabstrip_index = current_browser->tabstrip_model()->
+      GetIndexOfTabContents(initiator_tab)+1;

[Lei Zhang, 2010/11/12 23:17:18]

nit: foo + 1;

[kmadhusu, 2010/11/13 00:05:59]

Done.

+  browser::Navigate(&params);
+  TabContents* preview_tab = params.target_contents;
+  preview_tab->Activate();
+
+  // Add an entry to the map.
+  preview_tab_map_[preview_tab] = initiator_tab;
+  waiting_for_new_preview_page_ = true;
+
+  AddObservers(initiator_tab);
+  AddObservers(preview_tab);
+
+  return preview_tab;
+}
+
+void PrintPreviewTabController::Observe(NotificationType type,
+                                        const NotificationSource& source,
+                                        const NotificationDetails& details) {
+  TabContents* initiator_tab = NULL;
+  TabContents* preview_tab = NULL;
+  TabContents* source_tab = NULL;
+  NavigationController::LoadCommittedDetails* detail_info = NULL;
+
+  switch (type.value) {
+    case NotificationType::TAB_CONTENTS_DESTROYED: {
+      source_tab = Source<TabContents>(source).ptr();
+      break;
+    }
+    case NotificationType::NAV_ENTRY_COMMITTED: {
+      NavigationController* controller =
+          Source<NavigationController>(source).ptr();
+      source_tab = controller->tab_contents();
+      detail_info =
+          Details<NavigationController::LoadCommittedDetails>(details).ptr();
+      break;
+    }
+    default: {
+      NOTREACHED();
+      return;
+    }
+  }
+
+  if (IsPrintPreviewTab(source_tab)) {
+    // |source_tab| is preview tab.
+    initiator_tab = GetInitiatorTab(source_tab);
+    preview_tab = source_tab;
+  } else {
+    initiator_tab = source_tab;
+    preview_tab = GetPreviewTab(source_tab);
+  }
+
+  if (detail_info) {
+    PageTransition::Type transition_type =
+        detail_info->entry->transition_type();
+    NavigationType::Type nav_type = detail_info->type;
+
+    // Don't update/erase the map entry if the page has not changed.
+    bool reload = (transition_type == PageTransition::RELOAD ||
+                   nav_type == NavigationType::SAME_PAGE);
+    if (reload)
+      return;
+
+    // New |preview_tab| is created. Don't update/erase map entry.
+    bool is_preview_tab_loaded = (transition_type == PageTransition::LINK &&
+                                  nav_type == NavigationType::NEW_PAGE &&
+                                  source_tab == preview_tab);
+    if (waiting_for_new_preview_page_ && is_preview_tab_loaded) {
+      waiting_for_new_preview_page_ = false;
+      return;
+    }
+
+    // User navigated to existing |preview_tab| using forward/back button.
+    bool nav_to_prev_tab = (IsPrintPreviewTab(source_tab) &&
+                            transition_type == PageTransition::FORWARD_BACK &&
+                            nav_type == NavigationType::EXISTING_PAGE);
+    if (nav_to_prev_tab)
+      return;
+  }
+
+  // If |source_tab| is |initiator_tab|, update the map entry.
+  if (source_tab == initiator_tab) {
+    preview_tab_map_[preview_tab] = NULL;
+  }
+
+  // If |source_tab| is |preview_tab|, erase the map entry.
+  if (source_tab == preview_tab) {
+    EraseMapEntry(preview_tab);
+    RemoveObservers(preview_tab);
+  }
+
+  if (initiator_tab)
+    RemoveObservers(initiator_tab);
+}
+
+void PrintPreviewTabController::EraseMapEntry(TabContents* initiator_tab) {
+  preview_tab_map_.erase(initiator_tab);
+}
+
+} // namespace printing