interpres/bench_test.go

// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: MIT

package interpres

import (
	"context"
	"fmt"
	"strings"
	"testing"
	"time"
)

// benchDoc is a representative configuration document: every scalar kind, an
// inline table, sub-tables, and an array of tables.
var benchDoc = []byte(`title = "benchmark configuration"
replicas = 3
ratio = 0.75
enabled = true
when = 2026-09-17T12:00:00Z
local = 2026-09-17T12:00:00
tags = ["alpha", "beta", "gamma"]
limits = { cpu = 4, memory = 1024 }

[server]
host = "localhost"
port = 8080
hosts = ["a.example", "b.example"]

[server.tls]
enabled = true
cert = "/etc/cert.pem"

[[items]]
name = "first"
weight = 10
flags = ["x", "y"]

[[items]]
name = "second"
weight = 20
flags = ["z"]
`)

// longDoc is generated once so the large-input benchmarks measure parsing,
// not document construction. Roughly 2000 array-of-tables entries.
var longDoc = func() []byte {
	var b strings.Builder
	b.WriteString("title = \"long\"\n")
	for i := range 2000 {
		fmt.Fprintf(&b, "[[entry]]\nname = \"entry-%d\"\nweight = %d\nwhen = 2026-09-17T12:00:00Z\nratio = 0.5\ntags = [\"a\", \"b\", \"c\"]\n\n", i, i)
	}
	return []byte(b.String())
}()

type benchTLS struct {
	Enabled bool   `toml:"enabled"`
	Cert    string `toml:"cert"`
}

type benchServer struct {
	Host  string   `toml:"host"`
	Port  int      `toml:"port"`
	Hosts []string `toml:"hosts"`
	TLS   benchTLS `toml:"tls"`
}

type benchItem struct {
	Name   string   `toml:"name"`
	Weight int      `toml:"weight"`
	Flags  []string `toml:"flags"`
}

type benchConfig struct {
	Title    string         `toml:"title"`
	Replicas int            `toml:"replicas"`
	Ratio    float64        `toml:"ratio"`
	Enabled  bool           `toml:"enabled"`
	When     time.Time      `toml:"when"`
	Local    LocalDateTime  `toml:"local"`
	Tags     []string       `toml:"tags"`
	Limits   map[string]any `toml:"limits"`
	Server   benchServer    `toml:"server"`
	Items    []benchItem    `toml:"items"`
}

func BenchmarkParse(b *testing.B) {
	b.ReportAllocs()
	b.SetBytes(int64(len(benchDoc)))
	for b.Loop() {
		if _, err := ParseMap(benchDoc); err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkMarshal(b *testing.B) {
	tree, err := ParseMap(benchDoc)
	if err != nil {
		b.Fatal(err)
	}
	b.ReportAllocs()
	b.SetBytes(int64(len(benchDoc)))
	for b.Loop() {
		if _, err := Marshal(tree); err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkStrictDecode(b *testing.B) {
	dec := NewDecoder().DisallowUnknownFields()
	b.ReportAllocs()
	for b.Loop() {
		var cfg benchConfig
		if err := dec.Decode(benchDoc, &cfg); err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkParseLong(b *testing.B) {
	b.ReportAllocs()
	b.SetBytes(int64(len(longDoc)))
	for b.Loop() {
		if _, err := ParseMap(longDoc); err != nil {
			b.Fatal(err)
		}
	}
}

// benchLongEntry mirrors one [[entry]] element of longDoc for the typed
// decode of the long document.
type benchLongEntry struct {
	Name   string    `toml:"name"`
	Weight int       `toml:"weight"`
	When   time.Time `toml:"when"`
	Ratio  float64   `toml:"ratio"`
	Tags   []string  `toml:"tags"`
}

type benchLongDoc struct {
	Title string           `toml:"title"`
	Entry []benchLongEntry `toml:"entry"`
}

func BenchmarkStrictDecodeLong(b *testing.B) {
	dec := NewDecoder().DisallowUnknownFields()
	b.ReportAllocs()
	b.SetBytes(int64(len(longDoc)))
	for b.Loop() {
		var doc benchLongDoc
		if err := dec.Decode(longDoc, &doc); err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkMarshalLong(b *testing.B) {
	tree, err := ParseMap(longDoc)
	if err != nil {
		b.Fatal(err)
	}
	b.ReportAllocs()
	b.SetBytes(int64(len(longDoc)))
	for b.Loop() {
		if _, err := Marshal(tree); err != nil {
			b.Fatal(err)
		}
	}
}

// BenchmarkStrictDecodeTree measures the reference path the targeted decode
// is measured against: the full tree parse followed by the reflection walk.
// The pair runs in one process, so the A/B comparison shares the machine.
func BenchmarkStrictDecodeTree(b *testing.B) {
	dec := newDecoder()
	dec.disallowUnknown = true
	b.ReportAllocs()
	for b.Loop() {
		tree, _, err := parseWithOptions(context.Background(), benchDoc, parseOptions{}, false)
		if err != nil {
			b.Fatal(err)
		}
		var cfg benchConfig
		if err := dec.decode(tree, &cfg); err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkStrictDecodeTreeLong(b *testing.B) {
	dec := newDecoder()
	dec.disallowUnknown = true
	b.ReportAllocs()
	b.SetBytes(int64(len(longDoc)))
	for b.Loop() {
		tree, _, err := parseWithOptions(context.Background(), longDoc, parseOptions{}, false)
		if err != nil {
			b.Fatal(err)
		}
		var doc benchLongDoc
		if err := dec.decode(tree, &doc); err != nil {
			b.Fatal(err)
		}
	}
}