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
13 namespace net {
14
SingleRequestHostResolver(HostResolver * resolver)15 SingleRequestHostResolver::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
~SingleRequestHostResolver()24 SingleRequestHostResolver::~SingleRequestHostResolver() {
25 Cancel();
26 }
27
Resolve(const HostResolver::RequestInfo & info,RequestPriority priority,AddressList * addresses,const CompletionCallback & callback,const BoundNetLog & net_log)28 int 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
Cancel()57 void 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
OnResolveCompletion(int result)65 void 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