[ARROW-8623] [C++][Gandiva] Reduce use of Boost, remove Boost headers from header files

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0.0
• Component/s: C++, C++ - Gandiva
• External issue URL: https://github.com/apache/arrow/issues/24785
• Assignee: Wes McKinney
• Reporter: Wes McKinney
• Created: 29/Apr/20 14:45
• Updated: 11/Jan/23 08:01
• Resolved: 12/Jun/20 03:23

Description

Boost is currently a transitive dependency of many of Gandiva's public header files. I suggest the following:

• Do not include Boost transitively in any installed header file
• Reduce usages of Boost altogether

On the latter point, most usages of Boost can be trimmed by having a hash_combine function inside the Arrow codebase. See results of grepping the codebase

https://gist.github.com/wesm/190006d91628e6bf7c04deb596a52cff

It seems that Boost cannot be easily eliminated altogether at the present moment because of a use of Boost.Multiprecision (int256_t). At some point someone may want to implement sufficient 256-bit integer functions so that we don't have to depend on Boost.Multiprecision