hrw4u: native C++ parser and visitor for header_rewrite

[zwoop]

This essentially converted the existing Python parser / visitor / emitters to C++ and natively calling the various factory functions to create the object structure. In addition, it adds a new testing tool, hrw_confcmp, which compares an old vs a hrw4u configuration, and make sure they both create the same set of objects. As such, the header_rewrite core also added some support to identify the various Operators and Conditions. Usage:

leif@hel ~/BUILDS/ats-dbg » ./tools/hrw_confcmp/run_tests.sh  ~/apache/trafficserver/tools/hrw4u/tests/data/{hooks,conds,ops,vars,examples}

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Testing directory: hooks
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  ✓ hooks/read_response:             44 ms
  ✓ hooks/remap:                     39 ms
.
.
.
  ✓ examples/uuid:                   41 ms
  ✓ examples/x-debug:                41 ms

  Directory Summary: 18 passed, 0 failed (total: 18)

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Overall Summary
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  Total tests:  66
  Passed:       66
  Failed:       0

  Total time:   2721 ms
  Avg per test: 41 ms

✓ All tests passed!

[zwoop]

I'm making this a draft for now, I think it needs to go into ATS v11, since we're getting close to 10.2 branching and release.

[zwoop]

[approve ci debian]

[zwoop]

[approve ci rocky]

[bneradt]

[approve ci]

[bneradt]

I've verified that with your latest updates I can build this with our internal Yahoo tree in my dev box. However we will need to update our build infrastructure to contain antlr before I can test this in a production box.

I can deal with that over the next few weeks. In the meantime, let's land this work and we can steer the ship if need be.

[zwoop]

[approve ci]

[Copilot]

Pull request overview

This PR introduces a native C++ ANTLR4-based parser for the header_rewrite plugin, enabling direct parsing of .hrw4u configuration files without requiring external Python tooling. The implementation adds a new src/hrw4u library with visitor-based parsing, integrates it into the header_rewrite plugin, and includes a comparison tool (hrw_confcmp) to validate equivalence between legacy and hrw4u configurations.

Changes:

• Adds native C++ hrw4u parser library with ANTLR4 visitor implementation, type system, symbol resolution, and error handling
• Integrates native parser into header_rewrite plugin with factory bridge, object type system, and comparison interfaces
• Adds hrw_confcmp tool with test runner for validating configuration equivalence
• Updates Python tools for new operators (set-cc-alg, set-effective-address), improved reverse compilation, and TXN_CLOSE hook support
• Adds comprehensive .hrw4u test files and documentation updates

Reviewed changes

Copilot reviewed 85 out of 87 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/hrw4u/*	Native C++ parser implementation with visitor, types, tables, and error handling
include/hrw4u/*	Public API headers for parser library
plugins/header_rewrite/hrw4u.{cc,h}	Integration layer between parser and plugin
plugins/header_rewrite/objtypes.{cc,h}, types.h	Object type system for native parsing
plugins/header_rewrite/*.{cc,h}	Added type_name(), equals(), initialize() methods for comparison
tools/hrw_confcmp/*	Configuration comparison tool with test runner
tools/hrw4u/src/*	Python tool updates for new features and fixes
tests/gold_tests/*	New .hrw4u test files for existing tests
doc/admin-guide/*	Updated documentation for native parsing
CMakeLists.txt	Build system integration for new components