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 #ifndef NET_DNS_SINGLE_REQUEST_HOST_RESOLVER_H_ 6 #define NET_DNS_SINGLE_REQUEST_HOST_RESOLVER_H_ 7 8 #include "base/basictypes.h" 9 10 #include "net/base/completion_callback.h" 11 #include "net/base/net_export.h" 12 #include "net/base/request_priority.h" 13 #include "net/dns/host_resolver.h" 14 15 namespace net { 16 17 class AddressList; 18 class BoundNetLog; 19 20 // This class represents the task of resolving a hostname (or IP address 21 // literal) to an AddressList object. It wraps HostResolver to resolve only a 22 // single hostname at a time and cancels this request when going out of scope. 23 class NET_EXPORT SingleRequestHostResolver { 24 public: 25 // |resolver| must remain valid for the lifetime of |this|. 26 explicit SingleRequestHostResolver(HostResolver* resolver); 27 28 // If a completion callback is pending when the resolver is destroyed, the 29 // host resolution is cancelled, and the completion callback will not be 30 // called. 31 ~SingleRequestHostResolver(); 32 33 // Resolves the given hostname (or IP address literal), filling out the 34 // |addresses| object upon success. See HostResolver::Resolve() for details. 35 int Resolve(const HostResolver::RequestInfo& info, 36 RequestPriority priority, 37 AddressList* addresses, 38 const CompletionCallback& callback, 39 const BoundNetLog& net_log); 40 41 // Cancels the in-progress request, if any. This prevents the callback 42 // from being invoked. Resolve() can be called again after cancelling. 43 void Cancel(); 44 45 private: 46 // Callback for when the request to |resolver_| completes, so we dispatch 47 // to the user's callback. 48 void OnResolveCompletion(int result); 49 50 // The actual host resolver that will handle the request. 51 HostResolver* const resolver_; 52 53 // The current request (if any). 54 HostResolver::RequestHandle cur_request_; 55 CompletionCallback cur_request_callback_; 56 57 // Completion callback for when request to |resolver_| completes. 58 CompletionCallback callback_; 59 60 DISALLOW_COPY_AND_ASSIGN(SingleRequestHostResolver); 61 }; 62 63 } // namespace net 64 65 #endif // NET_DNS_SINGLE_REQUEST_HOST_RESOLVER_H_ 66