Benchmark inserting a line at the beginning of moby dick

editor-challenge/Cargo.toml

@@ -12,3 +12,8 @@ serde       = { version = "1", features = [ "derive" ] }
 serde_yml   = { version = "*" }
 thiserror   = { version = "1" }
 tui         = { version = "0.19", default-features = false, features = [ "crossterm", "serde" ] }
+
+[[bin]]
+name = "bench"
+main = "bin/bench.rs"
+features = [ "bench" ]

editor-challenge/src/bin/bench.rs

@@ -0,0 +1,5 @@
+use editor_challenge::types::bench::*;
+
+fn main() {
+    bench_insert_lines();
+}

editor-challenge/src/lib.rs

@@ -0,0 +1,5 @@
+pub mod ui;
+pub mod state;
+pub mod types;
+
+

editor-challenge/src/main.rs

@@ -1,9 +1,5 @@
-mod ui;
-mod state;
-mod types;
-
-use ui::Canvas;
 use crossterm::event::{self, KeyCode, KeyEvent, KeyModifiers};
+use editor_challenge::*;
 use state::AppState;
 use std::{
     env, io,
@@ -12,6 +8,7 @@ use std::{
     time::{Duration, Instant},
 };
 use tui::{backend::CrosstermBackend, Terminal};
+use ui::Canvas;
 
 // const TITLE: &str = "Text Editor Challenge";
 // const COPYRIGHT: &str = "(c) Savanni D'Gerinel - all rights reserved";

editor-challenge/src/types.rs

@@ -1,10 +1,9 @@
-
 // TODO: I'm increasingly feeling that cursors are per-document, not per-application. So I think I
 // want to move the cursor into here, and then rendering requires asking for the cursor for the
 // current document.
-#[derive(Default)]
+#[derive(Clone, Default)]
 pub struct Document {
-    rows: Vec<String>
+    rows: Vec<String>,
 }
 
 impl Document {
@@ -12,9 +11,7 @@ impl Document {
         if contents.len() > (u16::MAX.into()) {
             panic!("Document row count exceeds u16::MAX. The current scrolling code cannot handle that.");
         }
-        Self{
+        Self { rows: contents }
-            rows: contents
-        }
     }
 
     pub fn contents(&self) -> String {
@@ -29,7 +26,7 @@ impl Document {
         self.rows.len()
     }
 
-    pub fn insert_at(&mut self, cursor: &mut Cursor, c: char){
+    pub fn insert_at(&mut self, cursor: &mut Cursor, c: char) {
         let (row, column) = cursor.addr();
 
         self.rows[row].insert(column, c);
@@ -110,7 +107,86 @@ impl Cursor {
         }
         self.desired_column = self.column;
     }
-
 }
 
+mod test_utils {
+    use super::*;
+    use std::{
+        fs::File,
+        io::{BufRead, BufReader},
+        time::{Duration, Instant},
+    };
 
+    pub fn with_file<F>(test: F)
+    where
+        F: FnOnce(Document),
+    {
+        let f = File::open("fixtures/moby-dick.txt").unwrap();
+        let reader = BufReader::new(f);
+        let contents = reader
+            .lines()
+            .collect::<Result<Vec<String>, std::io::Error>>()
+            .unwrap();
+        let doc = Document::new(contents);
+        test(doc);
+    }
+
+    pub fn measure<F>(test: F) -> Duration
+    where
+        F: FnOnce(),
+    {
+        let start = Instant::now();
+        test();
+        let end = Instant::now();
+        end - start
+    }
+
+    pub fn benchmark<A>(
+        num_iterations: usize,
+        setup: impl Fn() -> A,
+        test: impl FnOnce(A) + Copy,
+    ) -> Duration {
+        let mut measurements: Duration = Duration::from_millis(0);
+
+        for _i in 0..num_iterations {
+            let data = setup();
+            measurements += measure(move || test(data))
+        }
+
+        measurements / (num_iterations as u32)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::{test_utils::*, *};
+
+    #[test]
+    fn it_inserts_a_line() {
+        with_file(|mut doc| {
+            let mut cursor = Cursor::default();
+
+            let num_lines = doc.row_count();
+            doc.new_line(&mut cursor);
+            assert_eq!(doc.row_count(), num_lines + 1);
+        });
+    }
+}
+
+pub mod bench {
+    use super::{test_utils::*, *};
+
+    pub fn bench_insert_lines() {
+        with_file(|doc| {
+            let performance = benchmark(
+                1000,
+                || doc.clone(),
+                |mut doc| {
+                    let mut cursor = Cursor::default();
+                    doc.new_line(&mut cursor);
+                },
+            );
+            println!("[bench_insert_lines] {:?}", performance);
+        });
+    }
+}