[JakubOnderka]

what

• refactor toHexIfNeeded function for improved performance and clarity

why

• toHexIfNeeded is used in converting request and response bodies, that can be pretty big
• current function performance is not optimal, the new approach is 5 times faster for 1 MB input

Input	Original	Optimized	Speedup
All printable	119 MB/s	692 MB/s	5.8x
10% binary	95 MB/s	439 MB/s	4.6x
All binary	35 MB/s	175 MB/s	5.0x

Summary by CodeRabbit

• Refactor
  • Updated how escaped text is formatted. Existing escaping rules and lowercase hexadecimal output are preserved; the change is internal and does not alter user-visible behavior.

[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

Run configuration

• Source mode: Auto
• Repository: Unavailable
• Branch: Unavailable
• File: No configuration file from this repository applied
• Commit: Unavailable
• Layers: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: 0f81414c-03b1-4994-9b5a-cc44ecb314fd

Commits

Reviewing files that changed from the base of the PR and between 1ebdc39 and 8a7a55e.

Files selected for processing: 1

• src/utils/string.h

Included review availability: This review used your included allowance. Your plan provides up to 8 included reviews per hour; 7 remain after this review.

Walkthrough

toHexIfNeeded now builds escaped output directly in a std::string with a lowercase hexadecimal lookup table. Its escaping conditions and \x output format remain unchanged.

Changes: Hex escaping utility

Layer / File(s)	Summary
Direct hexadecimal encoding src/utils/string.h	toHexIfNeeded replaces std::stringstream formatting with direct string construction and lowercase hexadecimal lookup. The existing escaping conditions remain unchanged.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Change: Refactor

Possibly related issues

• owasp-modsecurity/ModSecurity#3601: The PR rewrites the same utility but preserves the escape_spec condition, so it does not address the issue's requested call-site changes.

Suggested labels: 3.x

Suggested reviewers: eduar-hte, airween

Merge Risk: Minimal · up to 8a7a5

The refactor preserves the existing output contract and is ready to merge.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentat…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: refactoring toHexIfNeeded to improve string handling.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 1 functions across 1 files.

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

Finishing Touches

Generate unit tests (beta)

• Create a new PR

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

🟢 Approval recommended

The toHexIfNeeded refactor has no active review issues.

No open issues 🎉

What changed in this PR

Optimizes toHexIfNeeded, used when converting request and response bodies, by replacing stream formatting with direct string appends while preserving escaping rules and lowercase hexadecimal output.

Changes:

• Uses a hexadecimal lookup table instead of stream manipulators.
• Reserves initial output capacity based on the input size.

File	Description
src/​utils/​string.h	Refactors toHexIfNeeded to reduce string-formatting overhead.

_{Review effort: Balanced}