unique: add unique package and implement Make/Handle

This change adds the unique package for canonicalizing values, as
described by the proposal in #62483.

Fixes #62483.

Change-Id: I1dc3d34ec12351cb4dc3838a8ea29a5368d59e99
Reviewed-on: https://go-review.googlesource.com/c/go/+/574355
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ingo Oeser <nightlyone@googlemail.com>
Reviewed-by: David Chase <drchase@google.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/src/unique/handle_bench_test.go b/src/unique/handle_bench_test.go
new file mode 100644
index 0000000000..51f94c3f91
--- /dev/null
+++ b/src/unique/handle_bench_test.go
@@ -0,0 +1,63 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package unique
+
+import (
+	"fmt"
+	"runtime"
+	"testing"
+)
+
+func BenchmarkMake(b *testing.B) {
+	benchmarkMake(b, []string{"foo"})
+}
+
+func BenchmarkMakeMany(b *testing.B) {
+	benchmarkMake(b, testData[:])
+}
+
+func BenchmarkMakeManyMany(b *testing.B) {
+	benchmarkMake(b, testDataLarge[:])
+}
+
+func benchmarkMake(b *testing.B, testData []string) {
+	handles := make([]Handle[string], 0, len(testData))
+	for i := range testData {
+		handles = append(handles, Make(testData[i]))
+	}
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	b.RunParallel(func(pb *testing.PB) {
+		i := 0
+		for pb.Next() {
+			_ = Make(testData[i])
+			i++
+			if i >= len(testData) {
+				i = 0
+			}
+		}
+	})
+
+	b.StopTimer()
+
+	runtime.GC()
+	runtime.GC()
+}
+
+var (
+	testData      [128]string
+	testDataLarge [128 << 10]string
+)
+
+func init() {
+	for i := range testData {
+		testData[i] = fmt.Sprintf("%b", i)
+	}
+	for i := range testDataLarge {
+		testDataLarge[i] = fmt.Sprintf("%b", i)
+	}
+}