Cache failed DNS resolutions for 1 second....

net/base/host_cache.cc

 // Copyright (c) 2009 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/base/host_cache.h"
 
 #include "base/logging.h"
 #include "net/base/net_errors.h"
 
 namespace net {
 
 //-----------------------------------------------------------------------------
 
 HostCache::Entry::Entry(int error,
                         const AddressList& addrlist,
                         base::TimeTicks expiration)
     : error(error), addrlist(addrlist), expiration(expiration) {
 }
 
 HostCache::Entry::~Entry() {
 }
 
 //-----------------------------------------------------------------------------
 
-HostCache::HostCache(size_t max_entries, size_t cache_duration_ms)
-    : max_entries_(max_entries), cache_duration_ms_(cache_duration_ms) {
+HostCache::HostCache(size_t max_entries,
+                     base::TimeDelta success_entry_ttl,
+                     base::TimeDelta failure_entry_ttl)
+    : max_entries_(max_entries),
+      success_entry_ttl_(success_entry_ttl),
+      failure_entry_ttl_(failure_entry_ttl) {
 }
 
 HostCache::~HostCache() {
 }
 
 const HostCache::Entry* HostCache::Lookup(const Key& key,
                                           base::TimeTicks now) const {
   if (caching_is_disabled())
     return NULL;
 
   EntryMap::const_iterator it = entries_.find(key);
   if (it == entries_.end())
     return NULL;  // Not found.
 
   Entry* entry = it->second.get();
   if (CanUseEntry(entry, now))
     return entry;
 
   return NULL;
 }
 
 HostCache::Entry* HostCache::Set(const Key& key,
                                  int error,
                                  const AddressList addrlist,
                                  base::TimeTicks now) {
   if (caching_is_disabled())
     return NULL;
 
   base::TimeTicks expiration = now +
-      base::TimeDelta::FromMilliseconds(cache_duration_ms_);
+      (error == OK ? success_entry_ttl_ : failure_entry_ttl_);
 
   scoped_refptr<Entry>& entry = entries_[key];
   if (!entry) {
     // Entry didn't exist, creating one now.
     Entry* ptr = new Entry(error, addrlist, expiration);
     entry = ptr;
 
     // Compact the cache if we grew it beyond limit -- exclude |entry| from
     // being pruned though!
     if (entries_.size() > max_entries_)
       Compact(now, ptr);
     return ptr;
   } else {
     // Update an existing cache entry.
     entry->error = error;
     entry->addrlist = addrlist;
     entry->expiration = expiration;
     return entry.get();
   }
 }
 
 // static
 bool HostCache::CanUseEntry(const Entry* entry, const base::TimeTicks now) {
-  return entry->error == OK && entry->expiration > now;
+  return entry->expiration > now;
 }
 
 void HostCache::Compact(base::TimeTicks now, const Entry* pinned_entry) {
   // Clear out expired entries.
   for (EntryMap::iterator it = entries_.begin(); it != entries_.end(); ) {
     Entry* entry = (it->second).get();
     if (entry != pinned_entry && !CanUseEntry(entry, now)) {
       entries_.erase(it++);
     } else {
       ++it;
@@ skipping 15 matching lines @@
     } else {
       ++it;
     }
   }
 
   if (entries_.size() > max_entries_)
     DLOG(WARNING) << "Still above max entries limit";
 }
 
 }  // namespace net