Log the sync communication that happens between client and server.

chrome/browser/sync/engine/traffic_logger.cc

Index: chrome/browser/sync/engine/traffic_logger.cc
diff --git a/chrome/browser/sync/engine/traffic_logger.cc b/chrome/browser/sync/engine/traffic_logger.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6a39c7dc6f12d9a51ac8d51bd09590923a87761a
--- /dev/null
+++ b/chrome/browser/sync/engine/traffic_logger.cc
@@ -0,0 +1,47 @@
+// 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.
+
+#include "chrome/browser/sync/engine/traffic_logger.h"
+
+#include <string>
+
+#include "base/json/json_writer.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/sync/protocol/proto_value_conversions.h"
+#include "chrome/browser/sync/protocol/sync.pb.h"
+
+namespace browser_sync {
+
+namespace {
+template<class T>

[akalin, 2012/03/13 00:20:43]

space before <

[lipalani1, 2012/03/13 21:32:40]

Done.

+void LogData(const T& data,
+             DictionaryValue*(to_dictionary_value)(const T&, bool),

[akalin, 2012/03/13 00:20:43]

the right syntax is:

DictionaryValue* (*to_dictionary_value)(const T&, bool)

(declaration follows use)

(It probably just happens to work because of function->pointer-to-function
decay, but it's clearer not to rely on it, I think)

[lipalani1, 2012/03/13 21:32:40]

Yeah that is correct. I have seen this convention used in my previous job.
However I am OK converting to prepending *.
On 2012/03/13 00:20:43, akalin wrote:

+             const std::string& description) {
+  if (VLOG_IS_ON(1)) {
+    scoped_ptr<DictionaryValue> value(to_dictionary_value(data, true));

[akalin, 2012/03/13 00:20:43]

(*to_dictionary_value)(data, true)

[akalin, 2012/03/13 00:20:43]

comment what "true" means, like

(data, true /* parameter_name */)

[lipalani1, 2012/03/13 21:32:40]

Done.

+    std::string message;
+    base::JSONWriter::Write(value.get(), true, &message);

[akalin, 2012/03/13 00:20:43]

here too

[lipalani1, 2012/03/13 21:32:40]

Done.

+    VLOG(1) << "\n" << description;
+    VLOG(1) << "\n" << message;
+  }
+}
+}  // namespace
+
+void LogClientToServerMessage(const ClientToServerMessage& msg) {
+  LogData((sync_pb::ClientToServerMessage)msg, ClientToServerMessageToValue,

[akalin, 2012/03/13 00:20:43]

this is rendered moot by the comment in the header, but this is wrong; should be
a cast to a const ref (unless you're deliberately slicing the object)

[akalin, 2012/03/13 00:20:43]

&ClientToServerMessageToValue

[lipalani1, 2012/03/13 21:32:40]

Done.

[lipalani1, 2012/03/13 21:32:40]

The necessity for the cast was to have the template code pick it up. Otherwise
it is getting confused.
On 2012/03/13 00:20:43, akalin wrote:

[lipalani1, 2012/03/13 21:32:40]

Done.

+          "******Client To Server Message******");
+  // TODO(lipalani) : Store the data(minus specifics)
+  // in a circular buffer in memory.
+}
+
+void LogClientToServerResponse(
+    const sync_pb::ClientToServerResponse& response) {
+  LogData(response, ClientToServerResponseToValue,

[akalin, 2012/03/13 00:20:43]

&ClientToServerResponseToValue

[lipalani1, 2012/03/13 21:32:40]

Done.

+          "******Server Response******");
+  // TODO(lipalani) : Store the data(minus specifics)
+  // in a circular buffer in memory.
+}
+
+}  // namespace browser_sync