[net] Change factory methods for HostResolver and HostCache to return a scoped_ptr

net/base/host_resolver.h

 // Copyright (c) 2012 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_HOST_RESOLVER_H_
 #define NET_BASE_HOST_RESOLVER_H_
 
 #include <string>
 
+#include "base/memory/scoped_ptr.h"
 #include "net/base/address_family.h"
 #include "net/base/completion_callback.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/net_export.h"
 #include "net/base/net_util.h"
 #include "net/base/request_priority.h"
 
 namespace base {
 class Value;
 }
@@ skipping 68 matching lines @@
     // Whether this request was started by the DNS prefetcher.
     bool is_speculative_;
 
     // The priority for the request.
     RequestPriority priority_;
   };
 
   // Opaque type used to cancel a request.
   typedef void* RequestHandle;
 
-  // This value can be passed into CreateSystemHostResolver as the
+  // This value can be passed into CreateSystemResolver as the
   // |max_concurrent_resolves| parameter. It will select a default level of
   // concurrency.
   static const size_t kDefaultParallelism = 0;
 
-  // This value can be passed into CreateSystemHostResolver as the
-  // |max_retry_attempts| parameter. This is the maximum number of times we
-  // will retry for host resolution.
+  // This value can be passed into CreateSystemResolver as the
+  // |max_retry_attempts| parameter.
   static const size_t kDefaultRetryAttempts = -1;
 
   // If any completion callbacks are pending when the resolver is destroyed,
   // the host resolutions are cancelled, and the completion callbacks will not
   // be called.
   virtual ~HostResolver();
 
   // Resolves the given hostname (or IP address literal), filling out the
   // |addresses| object upon success.  The |info.port| parameter will be set as
   // the sin(6)_port field of the sockaddr_in{6} struct.  Returns OK if
@@ skipping 45 matching lines @@
 
   // Returns the HostResolverCache |this| uses, or NULL if there isn't one.
   // Used primarily to clear the cache and for getting debug information.
   virtual HostCache* GetHostCache();
 
   // Returns the current DNS configuration |this| is using, as a Value, or NULL
   // if it's configured to always use the system host resolver.  Caller takes
   // ownership of the returned Value.
   virtual base::Value* GetDnsConfigAsValue() const;
 
+  // Creates a HostResolver implementation that queries the underlying system.
+  // (Except if a unit-test has changed the global HostResolverProc using
+  // ScopedHostResolverProc to intercept requests to the system).
+  // |max_concurrent_resolves| is how many resolve requests will be allowed to
+  // run in parallel. Pass HostResolver::kDefaultParallelism to choose a
+  // default value.
+  // |max_retry_attempts| is the maximum number of times we will retry for host
+  // resolution. Pass HostResolver::kDefaultRetryAttempts to choose a default
+  // value.
+  // |enable_caching| controls whether a HostCache is used.
+  // |enable_async| controls whether a DnsClient is used.
+  static scoped_ptr<HostResolver> CreateSystemResolver(
+      size_t max_concurrent_resolves,

[darin (slow to review), 2012/10/09 17:38:34]

an Options struct containing these four fields would be nice here.

[szym, 2012/10/09 21:40:43]

Done.

+      size_t max_retry_attempts,
+      bool enable_caching,
+      bool enable_async,
+      NetLog* net_log);
+
+  // As above, but uses default parameters.
+  static scoped_ptr<HostResolver> CreateDefaultResolver(NetLog* net_log);
+
  protected:
   HostResolver();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(HostResolver);
 };
 
-// Creates a HostResolver implementation that queries the underlying system.
-// (Except if a unit-test has changed the global HostResolverProc using
-// ScopedHostResolverProc to intercept requests to the system).
-// |max_concurrent_resolves| is how many resolve requests will be allowed to
-// run in parallel. Pass HostResolver::kDefaultParallelism to choose a
-// default value.
-// |max_retry_attempts| is the maximum number of times we will retry for host
-// resolution. Pass HostResolver::kDefaultRetryAttempts to choose a default
-// value.
-// The created HostResolver uses an instance of DnsConfigService to retrieve
-// system DNS configuration.
-// This resolver should not be used in test context. Instead, use
-// MockHostResolver from net/base/mock_host_resolver.h.
-NET_EXPORT HostResolver* CreateSystemHostResolver(
-    size_t max_concurrent_resolves,
-    size_t max_retry_attempts,
-    NetLog* net_log);
-
-// As above, but the created HostResolver does not use a cache.
-NET_EXPORT HostResolver* CreateNonCachingSystemHostResolver(
-    size_t max_concurrent_resolves,
-    size_t max_retry_attempts,
-    NetLog* net_log);
-
-// As above, but the HostResolver will use the asynchronous DNS client in
-// DnsTransaction, which will be configured using DnsConfigService to match
-// the system DNS settings. If the client fails, the resolver falls back to
-// the global HostResolverProc.
-NET_EXPORT HostResolver* CreateAsyncHostResolver(size_t max_concurrent_resolves,
-                                                 size_t max_retry_attempts,
-                                                 NetLog* net_log);
 }  // namespace net
 
 #endif  // NET_BASE_HOST_RESOLVER_H_