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
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
|
// 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 defines ScopedHostMapper, which is a helper class for writing
// tests that use HostResolver either directly or indirectly.
//
// In most cases, it is important that unit tests avoid making actual DNS
// queries since the resulting tests can be flaky, especially if the network is
// unreliable for some reason. To simplify writing tests that avoid making
// actual DNS queries, the following helper class may be used:
//
// ScopedHostMapper scoped_host_mapper;
// scoped_host_mapper.AddRule("foo.com", "1.2.3.4");
// scoped_host_mapper.AddRule("bar.com", "2.3.4.5");
// ...
//
// The above rules define a static mapping from hostnames to IP address
// literals. The first parameter to AddRule specifies a host pattern to match
// against, and the second parameter indicates what value should be used to
// replace the given hostname. So, the following is also supported:
//
// scoped_host_mapper.AddRule("*.com", "127.0.0.1");
//
// If there are multiple ScopedHostMappers in existence, then the last one
// allocated will be used. However, if it does not provide a matching rule,
// then it will delegate to the previously set HostMapper (see SetHostMapper).
// Finally, if no HostMapper matches a given hostname, then the hostname will
// be unmodified.
//
// IMPORTANT: ScopedHostMapper is only designed to be used on a single thread,
// and it is a requirement that the lifetimes of multiple instances be nested.
#ifndef NET_BASE_SCOPED_HOST_MAPPER_H_
#define NET_BASE_SCOPED_HOST_MAPPER_H_
#ifdef UNIT_TEST
#include <list>
#include "base/string_util.h"
#include "net/base/host_resolver.h"
#include "net/base/net_errors.h"
namespace net {
// This class sets the HostMapper for a particular scope.
class ScopedHostMapper : public HostMapper {
public:
ScopedHostMapper() {
previous_host_mapper_ = SetHostMapper(this);
}
~ScopedHostMapper() {
HostMapper* old_mapper = SetHostMapper(previous_host_mapper_);
// The lifetimes of multiple instances must be nested.
CHECK(old_mapper == this);
}
// Any hostname matching the given pattern will be replaced with the given
// replacement value. Usually, replacement should be an IP address literal.
void AddRule(const char* host_pattern, const char* replacement) {
rules_.push_back(Rule(host_pattern, replacement));
}
private:
std::string Map(const std::string& host) {
RuleList::const_iterator r;
for (r = rules_.begin(); r != rules_.end(); ++r) {
if (MatchPattern(host, r->host_pattern))
return r->replacement;
}
return previous_host_mapper_ ? previous_host_mapper_->Map(host) : host;
}
struct Rule {
std::string host_pattern;
std::string replacement;
Rule(const char* h, const char* r) : host_pattern(h), replacement(r) {}
};
typedef std::list<Rule> RuleList;
HostMapper* previous_host_mapper_;
RuleList rules_;
};
} // namespace net
#endif // UNIT_TEST
#endif // NET_BASE_SCOPED_HOST_MAPPER_H_
|
