net/dns/notify_watcher_mac.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/dns/notify_watcher_mac.h"
   6
   7 #include <notify.h>
   8
   9 #include "base/logging.h"
  10 #include "base/posix/eintr_wrapper.h"
  11
  12 namespace net {
  13
  14 NotifyWatcherMac::NotifyWatcherMac() : notify_fd_(-1), notify_token_(-1) {}
  15
  16 NotifyWatcherMac::~NotifyWatcherMac() {
  17   Cancel();
  18 }
  19
  20 bool NotifyWatcherMac::Watch(const char* key, const CallbackType& callback) {
  21   DCHECK(key);
  22   DCHECK(!callback.is_null());
  23   Cancel();
  24   uint32_t status = notify_register_file_descriptor(
  25       key, &notify_fd_, 0, &notify_token_);
  26   if (status != NOTIFY_STATUS_OK)
  27     return false;
  28   DCHECK_GE(notify_fd_, 0);
  29   if (!base::MessageLoopForIO::current()->WatchFileDescriptor(
  30           notify_fd_,
  31           true,
  32           base::MessageLoopForIO::WATCH_READ,
  33           &watcher_,
  34           this)) {
  35     Cancel();
  36     return false;
  37   }
  38   callback_ = callback;
  39   return true;
  40 }
  41
  42 void NotifyWatcherMac::Cancel() {
  43   if (notify_fd_ >= 0) {
  44     notify_cancel(notify_token_);  // Also closes |notify_fd_|.
  45     notify_fd_ = -1;
  46     callback_.Reset();
  47     watcher_.StopWatchingFileDescriptor();
  48   }
  49 }
  50
  51 void NotifyWatcherMac::OnFileCanReadWithoutBlocking(int fd) {
  52   int token;
  53   int status = HANDLE_EINTR(read(notify_fd_, &token, sizeof(token)));
  54   if (status != sizeof(token)) {
  55     Cancel();
  56     callback_.Run(false);
  57     return;
  58   }
  59   // Ignoring |token| value to avoid possible endianness mismatch:
  60   // http://openradar.appspot.com/8821081
  61   callback_.Run(true);
  62 }
  63
  64 }  // namespace net