1// Copyright (c) 2011 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/single_request_host_resolver.h"
6
7#include "base/bind.h"
8#include "base/bind_helpers.h"
9#include "base/compiler_specific.h"
10#include "base/logging.h"
11#include "net/base/net_errors.h"
12
13namespace net {
14
15SingleRequestHostResolver::SingleRequestHostResolver(HostResolver* resolver)
16    : resolver_(resolver),
17      cur_request_(NULL),
18      callback_(
19          base::Bind(&SingleRequestHostResolver::OnResolveCompletion,
20                     base::Unretained(this))) {
21  DCHECK(resolver_ != NULL);
22}
23
24SingleRequestHostResolver::~SingleRequestHostResolver() {
25  Cancel();
26}
27
28int SingleRequestHostResolver::Resolve(const HostResolver::RequestInfo& info,
29                                       RequestPriority priority,
30                                       AddressList* addresses,
31                                       const CompletionCallback& callback,
32                                       const BoundNetLog& net_log) {
33  DCHECK(addresses);
34  DCHECK_EQ(false, callback.is_null());
35  DCHECK(cur_request_callback_.is_null()) << "resolver already in use";
36
37  HostResolver::RequestHandle request = NULL;
38
39  // We need to be notified of completion before |callback| is called, so that
40  // we can clear out |cur_request_*|.
41  CompletionCallback transient_callback =
42      callback.is_null() ? CompletionCallback() : callback_;
43
44  int rv = resolver_->Resolve(
45      info, priority, addresses, transient_callback, &request, net_log);
46
47  if (rv == ERR_IO_PENDING) {
48    DCHECK_EQ(false, callback.is_null());
49    // Cleared in OnResolveCompletion().
50    cur_request_ = request;
51    cur_request_callback_ = callback;
52  }
53
54  return rv;
55}
56
57void SingleRequestHostResolver::Cancel() {
58  if (!cur_request_callback_.is_null()) {
59    resolver_->CancelRequest(cur_request_);
60    cur_request_ = NULL;
61    cur_request_callback_.Reset();
62  }
63}
64
65void SingleRequestHostResolver::OnResolveCompletion(int result) {
66  DCHECK(cur_request_);
67  DCHECK_EQ(false, cur_request_callback_.is_null());
68
69  CompletionCallback callback = cur_request_callback_;
70
71  // Clear the outstanding request information.
72  cur_request_ = NULL;
73  cur_request_callback_.Reset();
74
75  // Call the user's original callback.
76  callback.Run(result);
77}
78
79}  // namespace net
80