net: move host_resolver files from net/base to net/dns

BUG=70818

Review URL: https://codereview.chromium.org/12518036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@189485 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 77 insertions, 0 deletions

diff --git a/net/dns/single_request_host_resolver.cc b/net/dns/single_request_host_resolver.cc
new file mode 100644
index 0000000..e926e86
--- /dev/null
+++ b/net/dns/single_request_host_resolver.cc
@@ -0,0 +1,77 @@
+// 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.
+
+#include "net/dns/single_request_host_resolver.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/compiler_specific.h"
+#include "base/logging.h"
+#include "net/base/net_errors.h"
+
+namespace net {
+
+SingleRequestHostResolver::SingleRequestHostResolver(HostResolver* resolver)
+    : resolver_(resolver),
+      cur_request_(NULL),
+      ALLOW_THIS_IN_INITIALIZER_LIST(callback_(
+          base::Bind(&SingleRequestHostResolver::OnResolveCompletion,
+                     base::Unretained(this)))) {
+  DCHECK(resolver_ != NULL);
+}
+
+SingleRequestHostResolver::~SingleRequestHostResolver() {
+  Cancel();
+}
+
+int SingleRequestHostResolver::Resolve(
+    const HostResolver::RequestInfo& info, AddressList* addresses,
+    const CompletionCallback& callback, const BoundNetLog& net_log) {
+  DCHECK(addresses);
+  DCHECK_EQ(false, callback.is_null());
+  DCHECK(cur_request_callback_.is_null()) << "resolver already in use";
+
+  HostResolver::RequestHandle request = NULL;
+
+  // We need to be notified of completion before |callback| is called, so that
+  // we can clear out |cur_request_*|.
+  CompletionCallback transient_callback =
+      callback.is_null() ? CompletionCallback() : callback_;
+
+  int rv = resolver_->Resolve(
+      info, addresses, transient_callback, &request, net_log);
+
+  if (rv == ERR_IO_PENDING) {
+    DCHECK_EQ(false, callback.is_null());
+    // Cleared in OnResolveCompletion().
+    cur_request_ = request;
+    cur_request_callback_ = callback;
+  }
+
+  return rv;
+}
+
+void SingleRequestHostResolver::Cancel() {
+  if (!cur_request_callback_.is_null()) {
+    resolver_->CancelRequest(cur_request_);
+    cur_request_ = NULL;
+    cur_request_callback_.Reset();
+  }
+}
+
+void SingleRequestHostResolver::OnResolveCompletion(int result) {
+  DCHECK(cur_request_);
+  DCHECK_EQ(false, cur_request_callback_.is_null());
+
+  CompletionCallback callback = cur_request_callback_;
+
+  // Clear the outstanding request information.
+  cur_request_ = NULL;
+  cur_request_callback_.Reset();
+
+  // Call the user's original callback.
+  callback.Run(result);
+}
+
+}  // namespace net