On 8/7/11 12:09 AM, dsimcha wrote:
On 8/6/2011 5:38 PM, jdrewsen wrote:
AFAIK David Nadlinger is handling serialization in his GSOC Thrift
project that he is working on currently.
Good to know, but what flavor?
The most important thing to note, and the reason it could not be
appropriate for what you want to do, is that the intended main use case
for Thrift is to define an interface that can easily be used from
several programming languages, feeling »native« for each of them
(similar to what protobuf does). As a consequence, Thrift by design only
supports value types, so it is not possible to e.g. serialize a tree or
a DAG without »flattening« it first.
Another important feature of Thrift is protocol versioning – you can
have required and optional fields, and the order of struct fields on the
wire is not defined. While the schemata themselves are never serialized,
the serialized data includes type tags and field ids for this purpose.
For the actual serialization format, there are several choices
available, currently implemented for D are the most popular ones:
Binary, which basically just dumps the raw bytes to the stream (all
numbers are written in network byte order, though), Compact, which is a
space-optimized binary protocol (zigzag varints, merging of some bytes
where you know you don't need all bits, …), and a »rich« JSON format.
These features obviously come at a (manageable) performance cost, but
except for that, the code is quite heavily optimized for reading/writing
performance. For example, while the protocols and transports (serialized
data sources/sinks) are pluggable at runtime, it is possible to
specialize all the serialization/RPC code for the actual implementations
used, thus eliminating all virtual calls and allowing e.g. the
serialization code for a struct to be inlined into a single function
without any control flow resp. the reading code into a single switch
statement (for the field ids) inside a loop.
But as said above, the second item from your list, flexibility with
regard to the types serialized, is a non-goal for Thrift, so it probably
isn't the best fit for your application.
David
