Add unit-tests for SingleRequestHostResolver.

To facilitate this, moved it out of host_resolver.cc to its own set of files.

BUG=84261
Review URL: http://codereview.chromium.org/6993015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@88006 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 57 insertions, 0 deletions

diff --git a/net/base/single_request_host_resolver.h b/net/base/single_request_host_resolver.h
new file mode 100644
index 0000000..6b9ec9b
--- /dev/null
+++ b/net/base/single_request_host_resolver.h
@@ -0,0 +1,57 @@
+// Copyright (c) 2011 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.
+
+#ifndef NET_BASE_SINGLE_REQUEST_HOST_RESOLVER_H_
+#define NET_BASE_SINGLE_REQUEST_HOST_RESOLVER_H_
+#pragma once
+
+#include "net/base/host_resolver.h"
+
+namespace net {
+
+// This class represents the task of resolving a hostname (or IP address
+// literal) to an AddressList object.  It wraps HostResolver to resolve only a
+// single hostname at a time and cancels this request when going out of scope.
+class NET_API SingleRequestHostResolver {
+ public:
+  // |resolver| must remain valid for the lifetime of |this|.
+  explicit SingleRequestHostResolver(HostResolver* resolver);
+
+  // If a completion callback is pending when the resolver is destroyed, the
+  // host resolution is cancelled, and the completion callback will not be
+  // called.
+  ~SingleRequestHostResolver();
+
+  // Resolves the given hostname (or IP address literal), filling out the
+  // |addresses| object upon success. See HostResolver::Resolve() for details.
+  int Resolve(const HostResolver::RequestInfo& info,
+              AddressList* addresses,
+              CompletionCallback* callback,
+              const BoundNetLog& net_log);
+
+  // Cancels the in-progress request, if any. This prevents the callback
+  // from being invoked. Resolve() can be called again after cancelling.
+  void Cancel();
+
+ private:
+  // Callback for when the request to |resolver_| completes, so we dispatch
+  // to the user's callback.
+  void OnResolveCompletion(int result);
+
+  // The actual host resolver that will handle the request.
+  HostResolver* const resolver_;
+
+  // The current request (if any).
+  HostResolver::RequestHandle cur_request_;
+  CompletionCallback* cur_request_callback_;
+
+  // Completion callback for when request to |resolver_| completes.
+  CompletionCallbackImpl<SingleRequestHostResolver> callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(SingleRequestHostResolver);
+};
+
+}  // namespace net
+
+#endif  // NET_BASE_SINGLE_REQUEST_HOST_RESOLVER_H_