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⚡ Bolt: Eliminate strings.ToLower allocation in content-type parsing #322

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⚡ Bolt: Eliminate strings.ToLower allocation in content-type parsing #322

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4 changes: 4 additions & 0 deletions .jules/bolt.md
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Original file line number Diff line number Diff line change
Expand Up @@ -21,3 +21,7 @@
## 2024-10-25 - Avoid mime.ParseMediaType for exact header matching
**Learning:** Using `mime.ParseMediaType` for exact or prefix header matching in hot paths introduces unnecessary memory allocations.
**Action:** When substituting with `strings.HasPrefix`, explicitly handle case-insensitivity (e.g., via `strings.ToLower`) to maintain HTTP standard compliance while preventing heavy parsing allocations.

## 2024-05-24 - Zero-Allocation Prefix Matching
**Learning:** Using strings.ToLower for case-insensitive header matching forces unnecessary memory allocations in hot paths.
**Action:** Use len(str) >= len(prefix) && strings.EqualFold(str[:len(prefix)], prefix) to achieve zero-allocation matching.
6 changes: 4 additions & 2 deletions cmd/sergeant-mcp-client/proxy.go
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Expand Up @@ -174,8 +174,10 @@ func (p *proxy) writeResponse(resp *response) {
return
}

// Performance optimization: Avoid mime.ParseMediaType allocation for exact header matching
isEventStream := strings.HasPrefix(strings.ToLower(resp.contentType), "text/event-stream")
// Performance optimization: Avoid mime.ParseMediaType allocation for exact header matching.
// Use EqualFold for zero-allocation case-insensitive prefix matching instead of strings.ToLower.
const prefix = "text/event-stream"
isEventStream := len(resp.contentType) >= len(prefix) && strings.EqualFold(resp.contentType[:len(prefix)], prefix)
p.outMu.Lock()
defer p.outMu.Unlock()
if isEventStream {
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