fix: improve sigv4 stream upload performance

[ferhatelmas]

What kind of change does this PR introduce?

Performance

What is the current behavior?

Sigv4 chunked parser uses Buffer.concat and rebuilds the unread buffer per chunk O(n^2)

What is the new behavior?

Use segmented queue and consume slice in place.
Add header/trailer offsets to scan delimiter from previous boundary instead of full payload.
Harden header parsing and drop writing raw line.
Create the digest only when needed (skip unsigned trailer, zero length terminal chunk).
Cache derived signing key.

[Copilot]

Pull request overview

This PR optimizes AWS SigV4 streaming (chunked) upload handling by reducing buffer-copy overhead in the chunk parser and caching derived signing keys to avoid repeated HMAC derivations during per-chunk verification.

Changes:

• Replaces per-write Buffer.concat behavior in the SigV4 chunk parser with a segmented buffer queue + in-place consumption and offset-based delimiter scanning.
• Hardens chunk header parsing/error messages and adds coverage for fragmented parsing cases (header/trailer boundaries).
• Caches derived SigV4 signing keys inside SignatureV4 to speed up repeated chunk signature validations within the same scope.

Reviewed changes

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

File	Description
src/storage/protocols/s3/signature-v4-stream.ts	Refactors the streaming chunk parser to use a segmented queue, adds delimiter search offsets, and reduces hashing work.
src/storage/protocols/s3/signature-v4.ts	Adds an in-instance derived signing key cache and switches call sites to use it.
src/test/signature-v4-stream.test.ts	Updates expectations for new error strings and adds tests for fragmented parsing + signing-key cache reuse.

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[coveralls]

Coverage Report for CI Build 24139634727

Coverage increased (+0.1%) to 80.916%

Details

• Coverage increased (+0.1%) from the base build.
• Patch coverage: 23 uncovered changes across 2 files (300 of 323 lines covered, 92.88%).
• No coverage regressions found.

Uncovered Changes

File	Changed	Covered	%
src/storage/protocols/s3/signature-v4-stream.ts	298	276	92.62%
src/storage/protocols/s3/signature-v4.ts	25	24	96.0%

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	37494
Covered Lines:	30516
Line Coverage:	81.39%
Relevant Branches:	4222
Covered Branches:	3239
Branch Coverage:	76.72%
Branches in Coverage %:	Yes
Coverage Strength:	315.6 hits per line

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💛 - Coveralls

[Copilot]

Pull request overview

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

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

---

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