refactor(api): replace regex literals with compiled patterns for improved performance and readability

[balazs-szucs]

Description of Changes

This pull request refactors several utility classes and controllers to replace inline regular expression usage with precompiled Pattern constants. This change improves performance, consistency, and maintainability by ensuring that regex patterns are compiled only once and reused throughout the codebase. Additionally, it enhances code clarity and security in filename and SQL content sanitization.

---

Checklist

General

• I have read the Contribution Guidelines
• I have read the Stirling-PDF Developer Guide (if applicable)
• I have read the How to add new languages to Stirling-PDF (if applicable)
• I have performed a self-review of my own code
• My changes generate no new warnings

Documentation

• I have updated relevant docs on Stirling-PDF's doc repo (if functionality has heavily changed)
• I have read the section Add New Translation Tags (for new translation tags only)

Translations (if applicable)

• I ran scripts/counter_translation.py

UI Changes (if applicable)

• Screenshots or videos demonstrating the UI changes are attached (e.g., as comments or direct attachments in the PR)

Testing (if applicable)

• I have run task check to verify linters, typechecks, and tests pass
• I have tested my changes locally. Refer to the Testing Guide for more details.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR reduces repeated regex compilation by introducing precompiled Pattern constants and switching from String.replaceAll(...) / String.matches(...) / String.split(...) to Pattern-based operations across storage providers, controllers, and utility/services.

Changes:

• Precompile commonly used regex patterns (control characters, newlines, whitespace, comments, share-link URI, non-alphanumerics) as static final Pattern.
• Replace inline regex calls (replaceAll, matches, split) with Pattern.matcher(...).replaceAll(...), matcher(...).matches(), and Pattern.split(...).
• Rename SQL normalization helper to sanitizeSql and apply precompiled patterns for script sanitization.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
app/proprietary/src/main/java/stirling/software/proprietary/storage/provider/S3StorageProvider.java	Precompile control-character regex and reuse it for filename/header sanitization.
app/proprietary/src/main/java/stirling/software/proprietary/storage/provider/LocalStorageProvider.java	Same control-character pattern optimization for local filename sanitization.
app/proprietary/src/main/java/stirling/software/proprietary/service/PdfCommentAgentOrchestrator.java	Precompile newline pattern for safer filename handling.
app/proprietary/src/main/java/stirling/software/proprietary/security/service/DatabaseService.java	Precompile comment/whitespace patterns and apply them in SQL sanitization; rename helper.
app/proprietary/src/main/java/stirling/software/proprietary/controller/api/PdfCommentAgentController.java	Precompile newline pattern for safe logging/filename handling.
app/proprietary/src/main/java/stirling/software/proprietary/controller/api/MathAuditorAgentController.java	Precompile newline pattern for safe logging/filename handling.
app/common/src/main/java/stirling/software/common/util/RequestUriUtils.java	Precompile share-link URI regex and use matcher().matches().
app/common/src/main/java/stirling/software/common/util/PdfTextLocator.java	Precompile non-alphanumeric regex used in normalization.
app/common/src/main/java/stirling/software/SPDF/pdf/parser/LineAlignmentTableParser.java	Precompile whitespace split pattern for tokenization.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.