Persist offline page info in a navigation entry if needed

components/sessions/content/content_serialized_navigation_builder.cc

 // Copyright 2014 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 "components/sessions/content/content_serialized_navigation_builder.h"
 
+#include "base/strings/string_tokenizer.h"
+#include "base/strings/string_util.h"
 #include "components/sessions/content/content_record_password_state.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/favicon_status.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/common/page_state.h"
 #include "content/public/common/referrer.h"
 
 namespace sessions {
 
+namespace {
+
+const char kOfflinePageHeader[] = "X-Chrome-offline";

[nasko, 2016/09/09 21:42:48]

Doesn't the full header value include ":" as well? I don't see it accounted for
anywhere.

[jianli, 2016/09/09 22:32:48]

Done.

+
+// Returns the offline page info that needs to be persisted, based on extra
+// headers.
+// TODO(jianli): Move this logic to components/offline_pages/request.

[nasko, 2016/09/09 21:42:48]

Is this TODO supposed to be resolved in later patchset or entirely different CL?
I'd suggest the former.

[jianli, 2016/09/09 22:32:48]

It will be in a different CL since doing it now in this patch will involve
restructure components/offline_pages directory which might make it hard to merge
to M54.

+std::string GetOfflinePageInfo(const content::NavigationEntry& entry) {
+  std::string extra_headers = entry.GetExtraHeaders();
+  if (extra_headers.empty())
+    return std::string();
+  // The offline header will be the only extra header if it is present.

[nasko, 2016/09/09 21:42:48]

There is no code that enforces that. Wouldn't adding another header in front of
the X-Chrome-offline one totally break your feature silently?

[jianli, 2016/09/09 22:32:48]

Most of time extra request header will not be sent. It will only be sent in a
few limited scenarios, like offline pages or data saver mode. It is not likely
that another header is also added together with offline header. Per discussion
with creis, we feel that limiting the extra header to only single offline header
will make the code more secure.

+  if (!base::StartsWith(extra_headers,
+                        kOfflinePageHeader,
+                        base::CompareCase::INSENSITIVE_ASCII)) {
+    return std::string();
+  }
+  std::string value = extra_headers.substr(arraysize(kOfflinePageHeader) - 1);

[nasko, 2016/09/09 21:42:48]

Doesn't arraysize require including base/macros.h?

[jianli, 2016/09/09 22:32:48]

Done.

+  base::StringTokenizer tokenizer(value, ", ");
+  while (tokenizer.GetNext()) {
+    if (tokenizer.token() == "persist=1")
+      return value;
+  }
+  return std::string();
+}
+
+}  // namespace
+
 // static
 SerializedNavigationEntry
 ContentSerializedNavigationBuilder::FromNavigationEntry(
     int index,
     const content::NavigationEntry& entry) {
   SerializedNavigationEntry navigation;
   navigation.index_ = index;
   navigation.unique_id_ = entry.GetUniqueID();
   navigation.referrer_url_ = entry.GetReferrer().url;
   navigation.referrer_policy_ = entry.GetReferrer().policy;
   navigation.virtual_url_ = entry.GetVirtualURL();
   navigation.title_ = entry.GetTitle();
   navigation.encoded_page_state_ = entry.GetPageState().ToEncodedData();
   navigation.transition_type_ = entry.GetTransitionType();
   navigation.has_post_data_ = entry.GetHasPostData();
   navigation.post_id_ = entry.GetPostID();
   navigation.original_request_url_ = entry.GetOriginalRequestURL();
   navigation.is_overriding_user_agent_ = entry.GetIsOverridingUserAgent();
   navigation.timestamp_ = entry.GetTimestamp();
   navigation.is_restored_ = entry.IsRestored();
   entry.GetExtraData(kSearchTermsKey, &navigation.search_terms_);
   if (entry.GetFavicon().valid)
     navigation.favicon_url_ = entry.GetFavicon().url;
   navigation.http_status_code_ = entry.GetHttpStatusCode();
   navigation.redirect_chain_ = entry.GetRedirectChain();
   navigation.password_state_ = GetPasswordStateFromNavigation(entry);
+  navigation.offline_page_info_ = GetOfflinePageInfo(entry);
 
   return navigation;
 }
 
 // static
 std::unique_ptr<content::NavigationEntry>
 ContentSerializedNavigationBuilder::ToNavigationEntry(
     const SerializedNavigationEntry* navigation,
     int page_id,
     content::BrowserContext* browser_context) {
   blink::WebReferrerPolicy policy =
       static_cast<blink::WebReferrerPolicy>(navigation->referrer_policy_);
+  // The extra headers, except the one used for offline page support, are not
+  // sync'ed across sessions.
+  std::string extra_headers;
+  if (!navigation->offline_page_info_.empty())
+    extra_headers = kOfflinePageHeader + navigation->offline_page_info_;

[nasko, 2016/09/09 21:42:48]

Shouldn't header name and value be separated by ":"?

[jianli, 2016/09/09 22:32:48]

Done.

   std::unique_ptr<content::NavigationEntry> entry(
       content::NavigationController::CreateNavigationEntry(
           navigation->virtual_url_,
           content::Referrer::SanitizeForRequest(
               navigation->virtual_url_,
               content::Referrer(navigation->referrer_url_, policy)),
           // Use a transition type of reload so that we don't incorrectly
           // increase the typed count.
           ui::PAGE_TRANSITION_RELOAD, false,
-          // The extra headers are not sync'ed across sessions.
-          std::string(), browser_context));
+          extra_headers, browser_context));
 
   entry->SetTitle(navigation->title_);
   entry->SetPageState(content::PageState::CreateFromEncodedData(
       navigation->encoded_page_state_));
   entry->SetPageID(page_id);
   entry->SetHasPostData(navigation->has_post_data_);
   entry->SetPostID(navigation->post_id_);
   entry->SetOriginalRequestURL(navigation->original_request_url_);
   entry->SetIsOverridingUserAgent(navigation->is_overriding_user_agent_);
   entry->SetTimestamp(navigation->timestamp_);
@@ skipping 18 matching lines @@
   std::vector<std::unique_ptr<content::NavigationEntry>> entries;
   entries.reserve(navigations.size());
   for (const auto& navigation : navigations) {
     entries.push_back(ToNavigationEntry(&navigation, page_id, browser_context));
     ++page_id;
   }
   return entries;
 }
 
 }  // namespace sessions