net/dns/mapped_host_resolver.h

   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 #ifndef NET_DNS_MAPPED_HOST_RESOLVER_H_
   6 #define NET_DNS_MAPPED_HOST_RESOLVER_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "net/base/host_mapping_rules.h"
  12 #include "net/base/net_export.h"
  13 #include "net/dns/host_resolver.h"
  14
  15 namespace net {
  16
  17 // This class wraps an existing HostResolver instance, but modifies the
  18 // request before passing it off to |impl|. This is different from
  19 // MockHostResolver which does the remapping at the HostResolverProc
  20 // layer, so it is able to preserve the effectiveness of the cache.
  21 class NET_EXPORT MappedHostResolver : public HostResolver {
  22  public:
  23   // Creates a MappedHostResolver that forwards all of its requests through
  24   // |impl|.
  25   explicit MappedHostResolver(scoped_ptr<HostResolver> impl);
  26   virtual ~MappedHostResolver();
  27
  28   // Adds a rule to this mapper. The format of the rule can be one of:
  29   //
  30   //   "MAP" <hostname_pattern> <replacement_host> [":" <replacement_port>]
  31   //   "EXCLUDE" <hostname_pattern>
  32   //
  33   // The <replacement_host> can be either a hostname, or an IP address literal,
  34   // or "~NOTFOUND". If it is "~NOTFOUND" then all matched hostnames will fail
  35   // to be resolved with ERR_NAME_NOT_RESOLVED.
  36   //
  37   // Returns true if the rule was successfully parsed and added.
  38   bool AddRuleFromString(const std::string& rule_string) {
  39     return rules_.AddRuleFromString(rule_string);
  40   }
  41
  42   // Takes a comma separated list of rules, and assigns them to this resolver.
  43   void SetRulesFromString(const std::string& rules_string) {
  44     rules_.SetRulesFromString(rules_string);
  45   }
  46
  47   // HostResolver methods:
  48   virtual int Resolve(const RequestInfo& info,
  49                       RequestPriority priority,
  50                       AddressList* addresses,
  51                       const CompletionCallback& callback,
  52                       RequestHandle* out_req,
  53                       const BoundNetLog& net_log) OVERRIDE;
  54   virtual int ResolveFromCache(const RequestInfo& info,
  55                                AddressList* addresses,
  56                                const BoundNetLog& net_log) OVERRIDE;
  57   virtual void CancelRequest(RequestHandle req) OVERRIDE;
  58   virtual void SetDnsClientEnabled(bool enabled) OVERRIDE;
  59   virtual HostCache* GetHostCache() OVERRIDE;
  60   virtual base::Value* GetDnsConfigAsValue() const OVERRIDE;
  61
  62  private:
  63   // Modify the request |info| according to |rules_|. Returns either OK or
  64   // the network error code that the hostname's resolution mapped to.
  65   int ApplyRules(RequestInfo* info) const;
  66
  67   scoped_ptr<HostResolver> impl_;
  68
  69   HostMappingRules rules_;
  70 };
  71
  72 }  // namespace net
  73
  74 #endif  // NET_DNS_MAPPED_HOST_RESOLVER_H_