1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
// Copyright (c) 2006-2008 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.
// This file supports network stack independent notification of progress
// towards resolving a hostname.
// The observer class supports exactly one active (Add'ed) instance, and in
// typical usage, that observer will be Add'ed during process startup, and
// Remove'd during process termination.
#ifndef NET_BASE_DNS_RESOLUTION_OBSERVER_H_
#define NET_BASE_DNS_RESOLUTION_OBSERVER_H_
#include <string>
namespace net {
class DnsResolutionObserver {
public:
virtual ~DnsResolutionObserver() {}
// For each OnStartResolution() notification, there should be a later
// OnFinishResolutionWithStatus() indicating completion of the resolution
// activity.
// Related pairs of notification will arrive with matching context values.
// A caller may use the context values to match up these asynchronous calls
// from among a larger call stream.
// Once a matching pair of notifications has been provided (i.e., a pair with
// identical context values), and the notification methods (below) have
// returned, the context values *might* be reused.
virtual void OnStartResolution(const std::string& name, void* context) = 0;
virtual void OnFinishResolutionWithStatus(bool was_resolved,
void* context) = 0;
};
// Note that *exactly* one observer is currently supported, and any attempt to
// add a second observer via AddDnsResolutionObserver() before removing the
// first DnsResolutionObserver will induce a DCHECK() assertion.
void AddDnsResolutionObserver(DnsResolutionObserver* new_observer);
// Note that the RemoveDnsResolutionObserver() will NOT perform any delete
// operations, and it is the responsibility of the code that called
// AddDnsResolutionObserver() to make a corresponding call to
// RemoveDnsResolutionObserver() and then delete the returned
// DnsResolutionObserver instance.
DnsResolutionObserver* RemoveDnsResolutionObserver();
// The following functions are expected to be called only by network stack
// implementations. This above observer class will relay the notifications
// to any registered observer.
void DidStartDnsResolution(const std::string& name, void* context);
void DidFinishDnsResolutionWithStatus(bool was_resolved, void* context);
} // namspace net
#endif // NET_BASE_DNS_RESOLUTION_OBSERVER_H_
|
