From 94a1c4830bacb672ed105fe35e6b6601cd521af3 Mon Sep 17 00:00:00 2001
From: Alberto Carretero <angelalbertoc.r@gmail.com>
Date: Mon, 16 Dec 2024 12:04:24 +0100
Subject: [PATCH] feat: optimize common case of GlobPath (#180)
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Results of the benchmark on my machine (using hyperfine with 10 rounds).

Basically, HEAD takes 5.341s on my machine compared to 18.366s for main.

$ bash benchmark.sh HEAD main
Creating rev: e2ee603c7396b33038e47352c0722b5b1202fbfe (main)
Creating rev: 19829794e6454f78334c9a67b74d8abb9bc66b25 (HEAD)
Benchmark 1: ./19829794e6454f78334c9a67b74d8abb9bc66b25 info --release ../chisel-releases/ubuntu-24.04 'python3.12_core'
  Time (mean ± σ):      5.341 s ±  0.115 s    [User: 5.528 s, System: 0.028 s]
  Range (min … max):    5.239 s …  5.635 s    10 runs

Benchmark 2: ./e2ee603c7396b33038e47352c0722b5b1202fbfe info --release ../chisel-releases/ubuntu-24.04 'python3.12_core'
  Time (mean ± σ):     18.366 s ±  0.139 s    [User: 19.677 s, System: 0.103 s]
  Range (min … max):   18.219 s … 18.675 s    10 runs

Summary
  ./19829794e6454f78334c9a67b74d8abb9bc66b25 info --release ../chisel-releases/ubuntu-24.04 'python3.12_core' ran
    3.44 ± 0.08 times faster than ./e2ee603c7396b33038e47352c0722b5b1202fbfe info --release ../chisel-releases/ubuntu-24.04 'python3.12_core'
---
 internal/strdist/strdist.go | 43 +++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/internal/strdist/strdist.go b/internal/strdist/strdist.go
index f205bfcf..d5b640ef 100644
--- a/internal/strdist/strdist.go
+++ b/internal/strdist/strdist.go
@@ -105,6 +105,15 @@ func Distance(a, b string, f CostFunc, cut int64) int64 {
 //	*  - Any zero or more characters, except for /
 //	** - Any zero or more characters, including /
 func GlobPath(a, b string) bool {
+	if !wildcardPrefixMatch(a, b) {
+		// Fast path.
+		return false
+	}
+	if !wildcardSuffixMatch(a, b) {
+		// Fast path.
+		return false
+	}
+
 	a = strings.ReplaceAll(a, "**", "⁑")
 	b = strings.ReplaceAll(b, "**", "⁑")
 	return Distance(a, b, globCost, 1) == 0
@@ -125,3 +134,37 @@ func globCost(ar, br rune) Cost {
 	}
 	return Cost{SwapAB: 1, DeleteA: 1, InsertB: 1}
 }
+
+// wildcardPrefixMatch compares whether the prefixes of a and b are equal up
+// to the shortest one. The prefix is defined as the longest substring that
+// starts at index 0 and does not contain a wildcard.
+func wildcardPrefixMatch(a, b string) bool {
+	ai := strings.IndexAny(a, "*?")
+	bi := strings.IndexAny(b, "*?")
+	if ai == -1 {
+		ai = len(a)
+	}
+	if bi == -1 {
+		bi = len(b)
+	}
+	mini := min(ai, bi)
+	return a[:mini] == b[:mini]
+}
+
+// wildcardSuffixMatch compares whether the suffixes of a and b are equal up
+// to the shortest one. The suffix is defined as the longest substring that ends
+// at the string length and does not contain a wildcard.
+func wildcardSuffixMatch(a, b string) bool {
+	ai := strings.LastIndexAny(a, "*?")
+	la := 0
+	if ai != -1 {
+		la = len(a) - ai - 1
+	}
+	lb := 0
+	bi := strings.LastIndexAny(b, "*?")
+	if bi != -1 {
+		lb = len(b) - bi - 1
+	}
+	minl := min(la, lb)
+	return a[len(a)-minl:] == b[len(b)-minl:]
+}