Add dbus::PopDataAsValue

dbus/values_util.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 DBUS_VALUES_UTIL_H_
+#define DBUS_VALUES_UTIL_H_
+#pragma once
+
+namespace base {
+class Value;
+}
+
+namespace dbus {
+
+class MessageReader;
+
+// Pops a value from |reader| as a base::Value.  Integer values larger than
+// int32 (including uint32) are converted to double.
+// Returns NULL if an error occurs.
+base::Value* PopDataAsValue(MessageReader* reader);

[satorux1, 2012/03/15 23:29:04]

Hmm, this looks like over engineering. 

I thought we wanted to add PopStringToVariantDictionary()  in MessageReader?

[hashimoto, 2012/03/15 23:38:18]

I thought having a complete tool to pop data as base::Value is good.
But it's true that no one needs to pop a struct or an array as base::Value now…

[hashimoto, 2012/03/16 02:45:52]

I once tried to write a simpler function which can pop string-to-variant
dictionaries only.
But the situation turns out to be more complicated.

Looking at Shill's code, Shill looks like outputting string-to-variant
dictionaries where the variants are containing either basic types, string array,
string-to-string map and string-to-variant.
(http://git.chromium.org/gitweb/?p=chromiumos/platform/shill.git;a=blob;f=dbus...)

It means that even if we decide to have a simple PopStringToVariantDictionary
function, it should be able to pop a complex string-to-variant dictionary with
basic types, array and dictionary (string-to-string and string-to-variant).
Since the function should be able to pop such complex data, the difference
between PopStringToVariantDictionary and PopDataAsValue is relatively small.

So I began to think PopStringToVariantDictionary is not so simpler than
PopDataAsValue and we better have PopDataAsValue, not
PopStringToVariantDictionary.
What do you think?

[satorux1, 2012/03/16 16:23:59]

Makes sense.

+
+}  // namespace dbus
+
+#endif  // DBUS_VALUES_UTIL_H_