QUIC - Allow cronet apps to specify how many server configs are to be

net/http/http_server_properties_impl.cc

Index: net/http/http_server_properties_impl.cc
diff --git a/net/http/http_server_properties_impl.cc b/net/http/http_server_properties_impl.cc
index 89754d241f7ef24ac48f3489c9d948a6193129cb..e84e4a86460d64b7648c815e5604c73839b634ff 100644
--- a/net/http/http_server_properties_impl.cc
+++ b/net/http/http_server_properties_impl.cc
@@ -33,7 +33,8 @@ HttpServerPropertiesImpl::HttpServerPropertiesImpl()
       spdy_settings_map_(SpdySettingsMap::NO_AUTO_EVICT),
       server_network_stats_map_(ServerNetworkStatsMap::NO_AUTO_EVICT),
       alternative_service_probability_threshold_(1.0),
-      quic_server_info_map_(kMaxQuicServersToPersist),
+      quic_server_info_map_(QuicServerInfoMap::NO_AUTO_EVICT),
+      max_server_configs_stored_in_properties_(kMaxQuicServersToPersist),
       weak_ptr_factory_(this) {
   canonical_suffixes_.push_back(".c.youtube.com");
   canonical_suffixes_.push_back(".googlevideo.com");
@@ -184,7 +185,7 @@ void HttpServerPropertiesImpl::InitializeServerNetworkStats(
 void HttpServerPropertiesImpl::InitializeQuicServerInfoMap(
     QuicServerInfoMap* quic_server_info_map) {
   // Add the entries from persisted data.
-  QuicServerInfoMap temp_map(kMaxQuicServersToPersist);
+  QuicServerInfoMap temp_map(QuicServerInfoMap::NO_AUTO_EVICT);
   for (QuicServerInfoMap::reverse_iterator it = quic_server_info_map->rbegin();
        it != quic_server_info_map->rend(); ++it) {
     temp_map.Put(it->first, it->second);
@@ -676,6 +677,26 @@ const QuicServerInfoMap& HttpServerPropertiesImpl::quic_server_info_map()
   return quic_server_info_map_;
 }
 
+int HttpServerPropertiesImpl::max_server_configs_stored_in_properties() const {
+  return max_server_configs_stored_in_properties_;
+}
+
+void HttpServerPropertiesImpl::set_max_server_configs_stored_in_properties(

[mef, 2016/01/15 16:12:32]

Should this be SetMaxServerConfigsStoredInProperties given that it is not just a
setter, but has a considerable side effect?

[ramant (doing other things), 2016/01/15 18:57:01]

Good point.

Done.

+    int max_server_configs_stored_in_properties) {
+  max_server_configs_stored_in_properties_ =
+      max_server_configs_stored_in_properties;
+
+  // MRUCache doesn't allow the size of the cache to be changed. Thus create a
+  // new map with the new size and add current elements and swap the new map.
+  QuicServerInfoMap temp_map(max_server_configs_stored_in_properties_);
+  for (QuicServerInfoMap::reverse_iterator it = quic_server_info_map_.rbegin();

[mef, 2016/01/15 16:12:32]

Microoptimization: quic_server_info_map_.ShrinkToSize first, and than copy
everything into new map. This will avoid copy-and-delete of entries that don't
fit into new map.

[ramant (doing other things), 2016/01/15 18:57:01]

+1. Thanks for the above optimization.

Done.

+       it != quic_server_info_map_.rend(); ++it) {
+    temp_map.Put(it->first, it->second);
+  }
+
+  quic_server_info_map_.Swap(temp_map);
+}
+
 void HttpServerPropertiesImpl::SetAlternativeServiceProbabilityThreshold(
     double threshold) {
   alternative_service_probability_threshold_ = threshold;