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https://issues.apache.org/jira/browse/THRIFT-539?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Nitay Joffe updated THRIFT-539:
-------------------------------
Attachment: thrift-539-hash.patch
Attaching patch for adding hash portion of this JIRA.
This patch adds a boost::hash compatible hashing function to each struct in the
IDL. It is optional to generate the function, because it adds a requirement on
boost/functional/hash.hpp. The option to enable it is called boost_hash.
Here is an example of running the thrift compiler with this patch to generate
the hash functions:
{noformat}
ni...@coeus ~/code/thrift/tutorial $ ../compiler/cpp/thrift -r --gen
cpp:boost_hash tutorial.thrift
{noformat}
Here is the hashing code that is generated for the tutorial:
{noformat}
std::size_t hash_value(const Work &v) {
std::size_t seed = 7;
boost::hash_combine(seed, v.num1);
boost::hash_combine(seed, v.num2);
boost::hash_combine(seed, v.op);
boost::hash_combine(seed, v.__isset.comment);
if (v.__isset.comment) {
boost::hash_combine(seed, v.comment);
}
return seed;
}
{noformat}
Note that the "comment" field is optional, so it is also optionally hashed.
Thoughts?
> struct hash and print methods for C++
> -------------------------------------
>
> Key: THRIFT-539
> URL: https://issues.apache.org/jira/browse/THRIFT-539
> Project: Thrift
> Issue Type: New Feature
> Components: Compiler (C++), Library (C++)
> Reporter: Nitay Joffe
> Priority: Minor
> Attachments: thrift-539-hash.patch
>
>
> The current thrift compiler for C++ generates methods for structs like
> operator== and operator< since it uses maps,sets, etc but it does not
> generate a hash() method or a human readable print() method.
> The idea of this issue is to add functionality to the C++ compiler to
> generate:
> # A boost hash compatible hash_value() function. This should probably be an
> option to the compiler as it adds a dependency in generated code on boost.
> # An operator<< function for printing structs in a nice form. This should be
> safe to always do?
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