[charliermarsh]

Reapplies #22078 for 0.13.

We store the same HTTP cache information in fewer bytes, without changing cache freshness or revalidation behavior.

• Booleans become bits. Ten fields like no_cache, no_store, and immutable each occupied a byte. We pack them into bits of one integer.
• Optional numbers share their presence flags. Each archived Option<u64> occupies 16 bytes: the number, an indicator of whether it exists, and alignment padding. We store the numbers together and use one bit per number to indicate whether it exists.

For example, max_age = None and max_age = Some(0) both store the number 0, but their presence bits differ. Getters reconstruct the normal Option<u64>.

We apply this to cache-control directives and response timestamps. The fixed archived policy shrinks from 320 to 200 bytes. We use bitflags for typed flag operations and retain endian-aware integers in the archived representation.

The cache bucket bumps cover the new representation.

[codspeed]

Merging this PR will improve performance by 5.64%

⚡ 1 improved benchmark
✅ 52 untouched benchmarks
⏩ 47 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	run_python_version_synthetic_workspace	272.7 ms	258.2 ms	+5.64%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing charlie/0.13-compact-http-cache-policy (42761b2) with main (e71ab8f)}

Footnotes

1. 47 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩