Fixed issue with some Epic Games not downloading (Required Header version parsing)

[phobos665]

Overview:

This fixes the parsing issue of a small number of games not downloading correctly.

Technical Details:

There are two versions of the header: V2 and v3.

V2 uses 62 bytes and V3 uses 66 Bytes.

We were only considering the 66 byte-length headers and it was failing.

Now appropriately checks the version and checks the header as expected.

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Improved download compatibility to support multiple header format versions.
  • Added validation and buffer protection to prevent data corruption from invalid headers.
  • Enhanced diagnostic logging to better track and troubleshoot download operations.

[cubic-dev-ai]

1 issue found across 1 file

Prompt for AI agents (all issues)

Check if these issues are valid — if so, understand the root cause of each and fix them.


<file name="app/src/main/java/app/gamenative/service/epic/EpicDownloadManager.kt">

<violation number="1" location="app/src/main/java/app/gamenative/service/epic/EpicDownloadManager.kt:686">
P2: `headerSize` is read from the chunk file and only checked for a minimum. A large/corrupt value will lead to `ByteArray(remainingSize)` allocating an unbounded amount of memory, which can crash the app. Add an upper bound on the header size before allocating.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[coderabbitai]

📝 Walkthrough

Walkthrough

Modifies header parsing in EpicDownloadManager.kt to support two header formats (62-byte and 66-byte) by adding validation, version-based conditional logic, buffer underflow guards, and expanded diagnostic logging.

Changes

Cohort / File(s)	Summary
Header Format Handling app/src/main/java/app/gamenative/service/epic/EpicDownloadManager.kt	Adds headerSize validation (62-66 bytes), conditional parsing based on headerVersion to handle legacy 62-byte and newer 66-byte formats, buffer underflow guard, and enhanced logging for version and computed uncompressedSize.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 Two headers dance, one old, one new,
Version checks determine what's true,
Buffers protected from underflow's bite,
Each format handled with parsing might! ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly reflects the main change: fixing a parsing issue for Epic Games downloads by implementing header version detection to handle both 62-byte and 66-byte header formats.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@app/src/main/java/app/gamenative/service/epic/EpicDownloadManager.kt`:
- Around line 684-688: The header size validation in EpicDownloadManager
(variable headerSize) currently allows any value between 62 and 66, but only
exact sizes 62 or 66 are valid; update the check to enforce (headerSize == 62 ||
headerSize == 66) and throw an Exception when not one of those exact values, and
adjust the exception message to state "Invalid header size: X (expected 62 or 66
bytes)" to make the constraint explicit; locate and modify the validation block
around headerSize in EpicDownloadManager.kt.

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

Tighten header size validation to exact 62/66 bytes.

The comment says only 62 or 66 are valid, but the current check allows 63–65 which can mask corrupted headers. Consider enforcing exact values.

🔧 Proposed fix

-            if (headerSize < 62 || headerSize > 66) {
-                throw Exception("Invalid header size: $headerSize (expected 62-66 bytes)")
-            }
+            if (headerSize != 62 && headerSize != 66) {
+                throw Exception("Invalid header size: $headerSize (expected 62 or 66 bytes)")
+            }

🤖 Prompt for AI Agents

In `@app/src/main/java/app/gamenative/service/epic/EpicDownloadManager.kt` around
lines 684 - 688, The header size validation in EpicDownloadManager (variable
headerSize) currently allows any value between 62 and 66, but only exact sizes
62 or 66 are valid; update the check to enforce (headerSize == 62 || headerSize
== 66) and throw an Exception when not one of those exact values, and adjust the
exception message to state "Invalid header size: X (expected 62 or 66 bytes)" to
make the constraint explicit; locate and modify the validation block around
headerSize in EpicDownloadManager.kt.