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      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_
     75