When the download folder does not exist, change the download folder to a user's "Downloads"

chrome/browser/ui/webui/options/advanced_options_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/ui/webui/options/advanced_options_handler.h"
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/path_service.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/download/download_manager.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/google/google_util.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_proxy_service.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_proxy_service_factory.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_setup_flow.h"
 #include "chrome/browser/printing/cloud_print/cloud_print_url.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/service/service_process_control.h"
 #include "chrome/browser/ui/options/options_util.h"
 #include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
 #include "content/browser/tab_contents/tab_contents.h"
 #include "content/browser/tab_contents/tab_contents_view.h"
 #include "content/browser/user_metrics.h"
 #include "content/common/content_notification_types.h"
 #include "content/common/notification_details.h"
 #include "grit/chromium_strings.h"
 #include "grit/generated_resources.h"
@@ skipping 157 matching lines @@
           GURL(chrome::kCloudPrintLearnMoreURL)).spec());
 #endif
 }
 
 void AdvancedOptionsHandler::Initialize() {
   DCHECK(web_ui_);
   SetupMetricsReportingCheckbox();
   SetupMetricsReportingSettingVisibility();
   SetupFontSizeLabel();
   SetupDownloadLocationPath();
+  download_path_checker_ = new DownloadPathChecker(this);
+  download_path_checker_->CheckIfDownloadPathExists(
+      default_download_location_.GetValue());
   SetupPromptForDownload();
   SetupAutoOpenFileTypesDisabledAttribute();
   SetupProxySettingsSection();
 #if !defined(OS_CHROMEOS)
   if (cloud_print_proxy_ui_enabled_) {
     SetupCloudPrintProxySection();
     RefreshCloudPrintStatusFromService();
   } else {
     RemoveCloudPrintProxySection();
   }
@@ skipping 367 matching lines @@
     label_str = l10n_util::GetStringUTF16(IDS_OPTIONS_EXTENSION_PROXIES_LABEL);
   } else {
     label_str = l10n_util::GetStringFUTF16(IDS_OPTIONS_SYSTEM_PROXIES_LABEL,
         l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
   }
   StringValue label(label_str);
 
   web_ui_->CallJavascriptFunction(
       "options.AdvancedOptions.SetupProxySettingsSection", disabled, label);
 }
+
+AdvancedOptionsHandler::DownloadPathChecker::DownloadPathChecker(
+    AdvancedOptionsHandler* handler)
+    : handler_(handler) {
+}
+
+AdvancedOptionsHandler::DownloadPathChecker::~DownloadPathChecker() {
+}
+
+void AdvancedOptionsHandler::DownloadPathChecker::
+                             CheckIfDownloadPathExists(const FilePath& path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
+      NewRunnableMethod(this,
+          &DownloadPathChecker::CheckIfDownloadPathExistsOnFileThread, path));
+}
+
+void AdvancedOptionsHandler::DownloadPathChecker::
+                             CheckIfDownloadPathExistsOnFileThread(
+                                 const FilePath& path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  if (!file_util::PathExists(path)) {
+    FilePath new_path;
+    if (!PathService::Get(chrome::DIR_DEFAULT_DOWNLOADS, &new_path)) {
+      // Create the |path| folder if we cannot get DIR_DEFAULT_DOWNLOADS
+      // (This will be a rare case).
+      new_path = path;
+    }
+    // Make sure that the folder does exist.
+    if (!file_util::CreateDirectory(new_path))
+      LOG(ERROR) << "Failed to create " << new_path.value();
+
+    BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+        NewRunnableMethod(this,
+            &DownloadPathChecker::OnDownloadPathChanged, new_path));
+  }
+}
+
+void AdvancedOptionsHandler::DownloadPathChecker::
+                             OnDownloadPathChanged(const FilePath path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (handler_) {
+    handler_->default_download_location_.SetValue(path);
+    handler_->SetupDownloadLocationPath();
+  }
+}