Add a GetSignature() method to dbus::MessageReader.

Add a GetSignature() method to dbus::MessageReader.

The new MessageReader::GetSignature() method returns the DBus signature
of the value at the current iterator position, which is needed for
implementing automatic de-serialization of complex DBus messages.

BUG=None
TEST=dbus_unittests

Committed: https://crrev.com/d2c6ebe6f58a49edd907f2d97f0c7d2234da8ae9
Cr-Commit-Position: refs/heads/master@{#291643}

[satorux1, 2014-08-25 05:33:28]

https://codereview.chromium.org/502793002/diff/1/dbus/message.cc
File dbus/message.cc (right):

https://codereview.chromium.org/502793002/diff/1/dbus/message.cc#newcode946
dbus/message.cc:946: dbus_message_iter_get_signature(&raw_message_iter_));
I understand the intention, but I guess calling dbus_free() is simpler. In fact,
it's not obvious if "scoped_ptr<char" is correct or "scoped_ptr<char*" is
correct here.

string signature;
char* raw_signature = dbus_message_iter_get_signature(...);
if (raw_signature) {
   signature = raw_signature;
   dbus_free(raw_signature);
}
return signature;

https://codereview.chromium.org/502793002/diff/1/dbus/message.h
File dbus/message.h (right):

https://codereview.chromium.org/502793002/diff/1/dbus/message.h#newcode114
dbus/message.h:114: std::string GetDataSignature();
At first, I thought 'Data' was not necessary, but we have GetDataType() so it
sounds like a good idea to have Data here for consistency.

https://codereview.chromium.org/502793002/diff/1/dbus/message_unittest.cc
File dbus/message_unittest.cc (right):

https://codereview.chromium.org/502793002/diff/1/dbus/message_unittest.cc#new...
dbus/message_unittest.cc:189: ASSERT_TRUE(reader.PopVariantOfByte(&byte_value));
maybe add tests for reader.GetDataSignature() in this function for the sake of
completeness?

https://codereview.chromium.org/502793002/diff/1/dbus/message_unittest.cc#new...
dbus/message_unittest.cc:303: MessageReader reader(message.get());
ditto. maybe add a test for reader.GetDataSignature() for completeness?

[Ben Chan, 2014-08-25 05:43:08]

PTAL

https://codereview.chromium.org/502793002/diff/1/dbus/message.cc
File dbus/message.cc (right):

https://codereview.chromium.org/502793002/diff/1/dbus/message.cc#newcode946
dbus/message.cc:946: dbus_message_iter_get_signature(&raw_message_iter_));
On 2014/08/25 05:33:27, satorux1 wrote:
> I understand the intention, but I guess calling dbus_free() is simpler. In
fact,
> it's not obvious if "scoped_ptr<char" is correct or "scoped_ptr<char*" is
> correct here.
> 
> string signature;
> char* raw_signature = dbus_message_iter_get_signature(...);
> if (raw_signature) {
>    signature = raw_signature;
>    dbus_free(raw_signature);
> }
> return signature;

Done.

https://codereview.chromium.org/502793002/diff/1/dbus/message.h
File dbus/message.h (right):

https://codereview.chromium.org/502793002/diff/1/dbus/message.h#newcode114
dbus/message.h:114: std::string GetDataSignature();
On 2014/08/25 05:33:27, satorux1 wrote:
> At first, I thought 'Data' was not necessary, but we have GetDataType() so it
> sounds like a good idea to have Data here for consistency.

yes, the reason behind is for consistency with GetDataType();

https://codereview.chromium.org/502793002/diff/1/dbus/message_unittest.cc
File dbus/message_unittest.cc (right):

https://codereview.chromium.org/502793002/diff/1/dbus/message_unittest.cc#new...
dbus/message_unittest.cc:189: ASSERT_TRUE(reader.PopVariantOfByte(&byte_value));
On 2014/08/25 05:33:27, satorux1 wrote:
> maybe add tests for reader.GetDataSignature() in this function for the sake of
> completeness?

Done.

https://codereview.chromium.org/502793002/diff/1/dbus/message_unittest.cc#new...
dbus/message_unittest.cc:303: MessageReader reader(message.get());
On 2014/08/25 05:33:27, satorux1 wrote:
> ditto. maybe add a test for reader.GetDataSignature() for completeness?

Done.

[satorux1, 2014-08-25 05:48:50]

LGTM

[Ben Chan, 2014-08-25 05:54:23]

The CQ bit was checked by benchan@chromium.org

[commit-bot: I haz the power, 2014-08-25 05:54:50]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/benchan@chromium.org/502793002/20001

[commit-bot: I haz the power, 2014-08-25 06:50:46]

Committed patchset #2 (20001) as 1566563089121040bd36e0c3c0062c363127a308

[commit-bot: I haz the power, 2014-09-10 02:33:09]

Patchset 2 (id:??) landed as
https://crrev.com/d2c6ebe6f58a49edd907f2d97f0c7d2234da8ae9
Cr-Commit-Position: refs/heads/master@{#291643}