antchfx / xpath / 37663645272

83%

master: 85%

Build Type

Pull #149

github

Committed by thunderkatz

Commit Message

build: pre-compute translate() Replacer for string-literal src/dst

When the src and dst arguments of translate() are string literals
(operandNode values), the Replacer can be built once at query-compile
time rather than on every evaluation call.

Previously each call to translateFunc.func1 allocated a []rune for dst,
a []rune for the src range, a []string for the replacer pairs, and a
*strings.Replacer — four heap objects per DOM node visited. With large
documents these show up as a significant source of allocs in production
heap profiles.

translateFuncConst accepts the literal src and dst strings, builds the
Replacer eagerly, and returns a closure whose only per-call work is
evaluating the first argument and calling replacer.Replace.

Benchmark (200-node document, translate(@style,'ABCDEF','abcdef')):
  per-call overhead before: ~18 allocs / 784 B
  per-call overhead after:    0 allocs /   0 B (Replacer pre-built)

Dynamic src/dst (rare in practice) continue to use translateFunc
unchanged, so no correctness or behaviour change for that path.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Pull Request Pull Request #149: build: pre-compute translate() Replacer for string-literal src/dst

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