Replace String with Arc<str> for etag and content_type fields in the
content cache. String::clone() allocates and copies the full string on
every cache hit (O(n)), while Arc<str>::clone() is O(1) — just an atomic
ref-count increment.
This eliminates 2 heap allocations per cache hit on the hottest download
path. At 1000 req/s that is 2000 fewer alloc/dealloc cycles per second.
Changed files:
- cache_ports.rs: trait signatures String → Arc<str>
- file_content_cache.rs: CacheEntry fields, get/put methods, tests
- stubs.rs: StubContentCachePort signatures
- file_retrieval_service.rs: caller creates Arc<str> before put()
Dionisio
cace61127f