| Index: net/base/dns_reload_timer.cc
|
| ===================================================================
|
| --- net/base/dns_reload_timer.cc (revision 99692)
|
| +++ net/base/dns_reload_timer.cc (working copy)
|
| @@ -1,100 +0,0 @@
|
| -// Copyright (c) 2010 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/dns_reload_timer.h"
|
| -
|
| -#if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD)
|
| -#include "base/lazy_instance.h"
|
| -#include "base/threading/thread_local_storage.h"
|
| -#include "base/time.h"
|
| -
|
| -namespace {
|
| -
|
| -// On Linux/BSD, changes to /etc/resolv.conf can go unnoticed thus resulting
|
| -// in DNS queries failing either because nameservers are unknown on startup
|
| -// or because nameserver info has changed as a result of e.g. connecting to
|
| -// a new network. Some distributions patch glibc to stat /etc/resolv.conf
|
| -// to try to automatically detect such changes but these patches are not
|
| -// universal and even patched systems such as Jaunty appear to need calls
|
| -// to res_ninit to reload the nameserver information in different threads.
|
| -//
|
| -// We adopt the Mozilla solution here which is to call res_ninit when
|
| -// lookups fail and to rate limit the reloading to once per second per
|
| -// thread.
|
| -//
|
| -// OpenBSD does not have thread-safe res_ninit/res_nclose so we can't do
|
| -// the same trick there.
|
| -
|
| -// Keep a timer per calling thread to rate limit the calling of res_ninit.
|
| -class DnsReloadTimer {
|
| - public:
|
| - // Check if the timer for the calling thread has expired. When no
|
| - // timer exists for the calling thread, create one.
|
| - bool Expired() {
|
| - const base::TimeDelta kRetryTime = base::TimeDelta::FromSeconds(1);
|
| - base::TimeTicks now = base::TimeTicks::Now();
|
| - base::TimeTicks* timer_ptr =
|
| - static_cast<base::TimeTicks*>(tls_index_.Get());
|
| -
|
| - if (!timer_ptr) {
|
| - timer_ptr = new base::TimeTicks();
|
| - *timer_ptr = base::TimeTicks::Now();
|
| - tls_index_.Set(timer_ptr);
|
| - // Return true to reload dns info on the first call for each thread.
|
| - return true;
|
| - } else if (now - *timer_ptr > kRetryTime) {
|
| - *timer_ptr = now;
|
| - return true;
|
| - } else {
|
| - return false;
|
| - }
|
| - }
|
| -
|
| - // Free the allocated timer.
|
| - static void SlotReturnFunction(void* data) {
|
| - base::TimeTicks* tls_data = static_cast<base::TimeTicks*>(data);
|
| - delete tls_data;
|
| - }
|
| -
|
| - private:
|
| - friend struct base::DefaultLazyInstanceTraits<DnsReloadTimer>;
|
| -
|
| - DnsReloadTimer() {
|
| - // During testing the DnsReloadTimer Singleton may be created and destroyed
|
| - // multiple times. Initialize the ThreadLocalStorage slot only once.
|
| - if (!tls_index_.initialized())
|
| - tls_index_.Initialize(SlotReturnFunction);
|
| - }
|
| -
|
| - ~DnsReloadTimer() {
|
| - }
|
| -
|
| - // We use thread local storage to identify which base::TimeTicks to
|
| - // interact with.
|
| - static base::ThreadLocalStorage::Slot tls_index_ ;
|
| -
|
| - DISALLOW_COPY_AND_ASSIGN(DnsReloadTimer);
|
| -};
|
| -
|
| -// A TLS slot to the TimeTicks for the current thread.
|
| -// static
|
| -base::ThreadLocalStorage::Slot DnsReloadTimer::tls_index_(
|
| - base::LINKER_INITIALIZED);
|
| -
|
| -base::LazyInstance<DnsReloadTimer,
|
| - base::LeakyLazyInstanceTraits<DnsReloadTimer> >
|
| - g_dns_reload_timer(base::LINKER_INITIALIZED);
|
| -
|
| -} // namespace
|
| -
|
| -namespace net {
|
| -
|
| -bool DnsReloadTimerHasExpired() {
|
| - DnsReloadTimer* dns_timer = g_dns_reload_timer.Pointer();
|
| - return dns_timer->Expired();
|
| -}
|
| -
|
| -} // namespace net
|
| -
|
| -#endif // defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_OPENBSD)
|
|
|