Cache failover to LOAD_PREFERRING_CACHE if network response suggests offline.

net/http/http_response_info.cc

 // Copyright (c) 2012 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 "net/http/http_response_info.h"
 
 #include "base/logging.h"
 #include "base/pickle.h"
 #include "base/time.h"
 #include "net/base/auth.h"
@@ skipping 63 matching lines @@
   RESPONSE_INFO_WAS_PROXY = 1 << 15,
 
   // This bit is set if the response info has an SSL connection status field.
   // This contains the ciphersuite used to fetch the resource as well as the
   // protocol version, compression method and whether SSLv3 fallback was used.
   RESPONSE_INFO_HAS_SSL_CONNECTION_STATUS = 1 << 16,
 
   // This bit is set if the response info has protocol version.
   RESPONSE_INFO_HAS_NPN_NEGOTIATED_PROTOCOL = 1 << 17,
 
+  // This bit is set if the request was overriden from cache due to
+  // various load flags being set.
+  RESPONSE_INFO_WAS_CACHE_OVERRIDE = 1 << 18,
+
   // TODO(darin): Add other bits to indicate alternate request methods.
   // For now, we don't support storing those.
 };
 
 HttpResponseInfo::HttpResponseInfo()
     : was_cached(false),
+      was_cache_override(false),
       was_fetched_via_spdy(false),
       was_npn_negotiated(false),
       was_fetched_via_proxy(false) {
 }
 
 HttpResponseInfo::HttpResponseInfo(const HttpResponseInfo& rhs)
     : was_cached(rhs.was_cached),
+      was_cache_override(rhs.was_cache_override),
       was_fetched_via_spdy(rhs.was_fetched_via_spdy),
       was_npn_negotiated(rhs.was_npn_negotiated),
       was_fetched_via_proxy(rhs.was_fetched_via_proxy),
       socket_address(rhs.socket_address),
       npn_negotiated_protocol(rhs.npn_negotiated_protocol),
       request_time(rhs.request_time),
       response_time(rhs.response_time),
       auth_challenge(rhs.auth_challenge),
       cert_request_info(rhs.cert_request_info),
       ssl_info(rhs.ssl_info),
       headers(rhs.headers),
       vary_data(rhs.vary_data),
       metadata(rhs.metadata) {
 }
 
 HttpResponseInfo::~HttpResponseInfo() {
 }
 
 HttpResponseInfo& HttpResponseInfo::operator=(const HttpResponseInfo& rhs) {
   was_cached = rhs.was_cached;
+  was_cache_override = rhs.was_cache_override;
   was_fetched_via_spdy = rhs.was_fetched_via_spdy;
   was_npn_negotiated = rhs.was_npn_negotiated;
   was_fetched_via_proxy = rhs.was_fetched_via_proxy;
   socket_address = rhs.socket_address;
   npn_negotiated_protocol = rhs.npn_negotiated_protocol;
   request_time = rhs.request_time;
   response_time = rhs.response_time;
   auth_challenge = rhs.auth_challenge;
   cert_request_info = rhs.cert_request_info;
   ssl_info = rhs.ssl_info;
@@ skipping 81 matching lines @@
     // info, so we don't fail if it can't be read.
     return false;
   }
 
   // read protocol-version.
   if (flags & RESPONSE_INFO_HAS_NPN_NEGOTIATED_PROTOCOL) {
     if (!pickle.ReadString(&iter, &npn_negotiated_protocol))
       return false;
   }
 
+  was_cache_override = (flags & RESPONSE_INFO_WAS_CACHE_OVERRIDE) != 0;
+
   was_fetched_via_spdy = (flags & RESPONSE_INFO_WAS_SPDY) != 0;
 
   was_npn_negotiated = (flags & RESPONSE_INFO_WAS_NPN) != 0;
 
   was_fetched_via_proxy = (flags & RESPONSE_INFO_WAS_PROXY) != 0;
 
   *response_truncated = (flags & RESPONSE_INFO_TRUNCATED) != 0;
 
   return true;
 }
 
 void HttpResponseInfo::Persist(Pickle* pickle,
                                bool skip_transient_headers,
                                bool response_truncated) const {
   int flags = RESPONSE_INFO_VERSION;
   if (ssl_info.is_valid()) {
     flags |= RESPONSE_INFO_HAS_CERT;
     flags |= RESPONSE_INFO_HAS_CERT_STATUS;
     if (ssl_info.security_bits != -1)
       flags |= RESPONSE_INFO_HAS_SECURITY_BITS;
     if (ssl_info.connection_status != 0)
       flags |= RESPONSE_INFO_HAS_SSL_CONNECTION_STATUS;
   }
   if (vary_data.is_valid())
     flags |= RESPONSE_INFO_HAS_VARY_DATA;
   if (response_truncated)
     flags |= RESPONSE_INFO_TRUNCATED;
+  if (was_cache_override)
+    flags |= RESPONSE_INFO_WAS_CACHE_OVERRIDE;
   if (was_fetched_via_spdy)
     flags |= RESPONSE_INFO_WAS_SPDY;
   if (was_npn_negotiated) {
     flags |= RESPONSE_INFO_WAS_NPN;
     flags |= RESPONSE_INFO_HAS_NPN_NEGOTIATED_PROTOCOL;
   }
   if (was_fetched_via_proxy)
     flags |= RESPONSE_INFO_WAS_PROXY;
 
   pickle->WriteInt(flags);
@@ skipping 28 matching lines @@
     vary_data.Persist(pickle);
 
   pickle->WriteString(socket_address.host());
   pickle->WriteUInt16(socket_address.port());
 
   if (was_npn_negotiated)
     pickle->WriteString(npn_negotiated_protocol);
 }
 
 }  // namespace net