GH-19667: [C++][Gandiva] Use arrow::Result<std::string> for RegexUtil::SqlLikePatternToPcre

[Reranko05]

Rationale for this change

Replace the Status + out-parameter pattern in RegexUtil::SqlLikePatternToPcre with arrow::Result<std::string>, aligning with modern Arrow API practices.

What changes are included in this PR?

• Updated RegexUtil::SqlLikePatternToPcre to return arrow::Result<std::string> instead of using an out-parameter
• Updated call sites in regex_functions_holder.cc to use ARROW_ASSIGN_OR_RAISE
• Updated tests in regex_functions_holder_test.cc to use ASSERT_OK_AND_ASSIGN
• Removed GANDIVA_EXPORT from the inline wrapper to avoid Windows dllimport issues
• Simplified control flow in regex_functions_holder.cc

Are these changes tested?

• Rebuilt with ninja gandiva
• Ran Gandiva tests successfully

Are there any user-facing changes?

Yes.

• GitHub Issue: [Gandiva] Remove usages of mutable reference out arguments #19667

[github-actions]

⚠️ GitHub issue #19667 has been automatically assigned in GitHub to PR creator.

[Reranko05]

@kou opened this PR for discussion.

[Copilot]

Pull request overview

This PR updates Gandiva’s RegexUtil::SqlLikePatternToPcre API to avoid mutable reference out-parameters and propagates the change through local LIKE holder call sites and tests.

Changes:

• Changed RegexUtil::SqlLikePatternToPcre to return arrow::Result<std::string> instead of writing into a mutable out-parameter.
• Updated LikeHolder creation paths to use ARROW_ASSIGN_OR_RAISE with the new API.
• Updated the affected unit test to consume the new Result<std::string> return type.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
cpp/src/gandiva/regex_util.h	Updates the public API signature and export annotations for SqlLikePatternToPcre.
cpp/src/gandiva/regex_util.cc	Implements the new Result<std::string>-returning conversion function.
cpp/src/gandiva/regex_functions_holder.cc	Adapts LIKE holder construction to the new RegexUtil API.
cpp/src/gandiva/regex_functions_holder_test.cc	Updates a test to use the new Result<std::string> return value.

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[kou]

+1

Could you update the PR title and description?

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

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[Reranko05]

@kou updated the PR title and description as suggested. Also addressed the minor comment in the code.

Thanks for the review!

[kou]

Thanks.

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