From 701be9315d865ba8a3a9c312a292d7998944760d Mon Sep 17 00:00:00 2001
From: EdJoPaTo
 <rfc-conform-git-commit-email@funny-long-domain-label-everyone-hates-as-it-is-too-long.edjopato.de>
Date: Tue, 30 Apr 2024 22:38:16 +0200
Subject: [PATCH] test(bench): add benchmark

---
 Cargo.toml       |  13 +++++
 benches/bench.rs | 144 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 157 insertions(+)
 create mode 100644 benches/bench.rs

diff --git a/Cargo.toml b/Cargo.toml
index 0072b1b..6d2f274 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,10 +17,23 @@ unsafe_code = "forbid"
 pedantic = "warn"
 nursery = "warn"
 
+[profile.bench]
+codegen-units = 1
+debug = true
+lto = true
+
 [dependencies]
 ratatui = { version = "0.26", default-features = false }
 unicode-width = "0.1"
 
 [dev-dependencies]
+criterion = "0.5"
 crossterm = "0.27"
 ratatui = "0.26"
+
+[target.'cfg(target_family = "unix")'.dev-dependencies]
+pprof = { version = "0.13", features = ["criterion", "flamegraph"] }
+
+[[bench]]
+name = "bench"
+harness = false
diff --git a/benches/bench.rs b/benches/bench.rs
new file mode 100644
index 0000000..d2212a7
--- /dev/null
+++ b/benches/bench.rs
@@ -0,0 +1,144 @@
+use std::hint::black_box;
+
+use criterion::{criterion_group, criterion_main, BatchSize, Criterion, Throughput};
+use ratatui::buffer::Buffer;
+use ratatui::layout::Rect;
+use ratatui::widgets::StatefulWidget;
+use tui_tree_widget::{Tree, TreeItem, TreeState};
+
+fn example_items() -> Vec<TreeItem<'static, &'static str>> {
+    vec![
+        TreeItem::new_leaf("a", "Alfa"),
+        TreeItem::new(
+            "b",
+            "Bravo",
+            vec![
+                TreeItem::new_leaf("c", "Charlie"),
+                TreeItem::new(
+                    "d",
+                    "Delta",
+                    vec![
+                        TreeItem::new_leaf("e", "Echo"),
+                        TreeItem::new_leaf("f", "Foxtrot"),
+                    ],
+                )
+                .expect("all item identifiers are unique"),
+                TreeItem::new_leaf("g", "Golf"),
+            ],
+        )
+        .expect("all item identifiers are unique"),
+        TreeItem::new_leaf("h", "Hotel"),
+        TreeItem::new(
+            "i",
+            "India",
+            vec![
+                TreeItem::new_leaf("j", "Juliett"),
+                TreeItem::new_leaf("k", "Kilo"),
+                TreeItem::new_leaf("l", "Lima"),
+                TreeItem::new_leaf("m", "Mike"),
+                TreeItem::new_leaf("n", "November"),
+            ],
+        )
+        .expect("all item identifiers are unique"),
+        TreeItem::new_leaf("o", "Oscar"),
+        TreeItem::new(
+            "p",
+            "Papa",
+            vec![
+                TreeItem::new_leaf("q", "Quebec"),
+                TreeItem::new_leaf("r", "Romeo"),
+                TreeItem::new_leaf("s", "Sierra"),
+                TreeItem::new_leaf("t", "Tango"),
+                TreeItem::new_leaf("u", "Uniform"),
+                TreeItem::new(
+                    "v",
+                    "Victor",
+                    vec![
+                        TreeItem::new_leaf("w", "Whiskey"),
+                        TreeItem::new_leaf("x", "Xray"),
+                        TreeItem::new_leaf("y", "Yankee"),
+                    ],
+                )
+                .expect("all item identifiers are unique"),
+            ],
+        )
+        .expect("all item identifiers are unique"),
+        TreeItem::new_leaf("z", "Zulu"),
+    ]
+}
+
+fn init(criterion: &mut Criterion) {
+    let mut group = criterion.benchmark_group("init");
+    group.throughput(Throughput::Elements(1)); // Frames per second
+
+    group.bench_function("empty", |bencher| {
+        bencher.iter(|| {
+            let items: Vec<TreeItem<usize>> = vec![];
+            black_box(Tree::new(black_box(items))).unwrap();
+        });
+    });
+
+    group.bench_function("example-items", |bencher| {
+        bencher.iter(|| {
+            let items = example_items();
+            black_box(Tree::new(black_box(items))).unwrap();
+        });
+    });
+
+    group.finish();
+}
+
+fn renders(criterion: &mut Criterion) {
+    let mut group = criterion.benchmark_group("render");
+    group.throughput(Throughput::Elements(1)); // Frames per second
+
+    let buffer_size = Rect::new(0, 0, 100, 100);
+
+    group.bench_function("empty", |bencher| {
+        let items: Vec<TreeItem<usize>> = vec![];
+        let tree = Tree::new(items).unwrap();
+        let mut state = TreeState::default();
+        bencher.iter_batched(
+            || (tree.clone(), Buffer::empty(buffer_size)),
+            |(tree, mut buffer)| {
+                black_box(tree).render(buffer_size, black_box(&mut buffer), black_box(&mut state));
+            },
+            BatchSize::SmallInput,
+        );
+    });
+
+    group.bench_function("example-items", |bencher| {
+        let items = example_items();
+        let tree = Tree::new(items).unwrap();
+        let mut state = TreeState::default();
+        state.open(vec!["b"]);
+        state.open(vec!["b", "d"]);
+        bencher.iter_batched(
+            || (tree.clone(), Buffer::empty(buffer_size)),
+            |(tree, mut buffer)| {
+                black_box(tree).render(buffer_size, black_box(&mut buffer), black_box(&mut state));
+            },
+            BatchSize::SmallInput,
+        );
+    });
+
+    group.finish();
+}
+
+/// Create flamegraphs with `cargo bench --bench bench -- --profile-time=5`
+#[cfg(unix)]
+fn profiled() -> Criterion {
+    use pprof::criterion::{Output, PProfProfiler};
+    Criterion::default().with_profiler(PProfProfiler::new(100, Output::Flamegraph(None)))
+}
+#[cfg(not(unix))]
+fn profiled() -> Criterion {
+    Criterion::default()
+}
+
+criterion_group! {
+    name = benches;
+    config = profiled();
+    targets = init, renders
+}
+criterion_main!(benches);