From fc1f9f012431b129dea850443b6b3b8a760a45e1 Mon Sep 17 00:00:00 2001 From: mo8it Date: Thu, 29 Aug 2024 01:56:45 +0200 Subject: [PATCH] Optimize reading and writing the state file --- src/app_state.rs | 138 ++++++++++++++++++++++++++--------------------- 1 file changed, 76 insertions(+), 62 deletions(-) diff --git a/src/app_state.rs b/src/app_state.rs index 2a205682..ef2f8741 100644 --- a/src/app_state.rs +++ b/src/app_state.rs @@ -1,8 +1,8 @@ use anyhow::{bail, Context, Result}; use std::{ env, - fs::{self, File}, - io::{self, Read, StdoutLock, Write}, + fs::{File, OpenOptions}, + io::{self, Read, Seek, StdoutLock, Write}, path::Path, process::{Command, Stdio}, thread, @@ -18,7 +18,6 @@ use crate::{ }; const STATE_FILE_NAME: &str = ".rustlings-state.txt"; -const BAD_INDEX_ERR: &str = "The current exercise index is higher than the number of exercises"; #[must_use] pub enum ExercisesProgress { @@ -47,6 +46,7 @@ pub struct AppState { // Caches the number of done exercises to avoid iterating over all exercises every time. n_done: u16, final_message: String, + state_file: File, // Preallocated buffer for reading and writing the state file. file_buf: Vec, official_exercises: bool, @@ -56,59 +56,22 @@ pub struct AppState { } impl AppState { - // Update the app state from the state file. - fn update_from_file(&mut self) -> StateFileStatus { - self.file_buf.clear(); - self.n_done = 0; - - if File::open(STATE_FILE_NAME) - .and_then(|mut file| file.read_to_end(&mut self.file_buf)) - .is_err() - { - return StateFileStatus::NotRead; - } - - // See `Self::write` for more information about the file format. - let mut lines = self.file_buf.split(|c| *c == b'\n').skip(2); - - let Some(current_exercise_name) = lines.next() else { - return StateFileStatus::NotRead; - }; - - if current_exercise_name.is_empty() || lines.next().is_none() { - return StateFileStatus::NotRead; - } - - let mut done_exercises = hash_set_with_capacity(self.exercises.len()); - - for done_exerise_name in lines { - if done_exerise_name.is_empty() { - break; - } - done_exercises.insert(done_exerise_name); - } - - for (ind, exercise) in self.exercises.iter_mut().enumerate() { - if done_exercises.contains(exercise.name.as_bytes()) { - exercise.done = true; - self.n_done += 1; - } - - if exercise.name.as_bytes() == current_exercise_name { - self.current_exercise_ind = ind; - } - } - - StateFileStatus::Read - } - pub fn new( exercise_infos: Vec, final_message: String, ) -> Result<(Self, StateFileStatus)> { let cmd_runner = CmdRunner::build()?; + let mut state_file = OpenOptions::new() + .create(true) + .read(true) + .write(true) + .truncate(false) + .open(STATE_FILE_NAME) + .with_context(|| { + format!("Failed to open or create the state file {STATE_FILE_NAME}") + })?; - let exercises = exercise_infos + let mut exercises = exercise_infos .into_iter() .map(|exercise_info| { // Leaking to be able to borrow in the watch mode `Table`. @@ -126,25 +89,69 @@ impl AppState { test: exercise_info.test, strict_clippy: exercise_info.strict_clippy, hint, - // Updated in `Self::update_from_file`. + // Updated below. done: false, } }) .collect::>(); - let mut slf = Self { - current_exercise_ind: 0, + let mut current_exercise_ind = 0; + let mut n_done = 0; + let mut file_buf = Vec::with_capacity(2048); + let state_file_status = 'block: { + if state_file.read_to_end(&mut file_buf).is_err() { + break 'block StateFileStatus::NotRead; + } + + // See `Self::write` for more information about the file format. + let mut lines = file_buf.split(|c| *c == b'\n').skip(2); + + let Some(current_exercise_name) = lines.next() else { + break 'block StateFileStatus::NotRead; + }; + + if current_exercise_name.is_empty() || lines.next().is_none() { + break 'block StateFileStatus::NotRead; + } + + let mut done_exercises = hash_set_with_capacity(exercises.len()); + + for done_exerise_name in lines { + if done_exerise_name.is_empty() { + break; + } + done_exercises.insert(done_exerise_name); + } + + for (ind, exercise) in exercises.iter_mut().enumerate() { + if done_exercises.contains(exercise.name.as_bytes()) { + exercise.done = true; + n_done += 1; + } + + if exercise.name.as_bytes() == current_exercise_name { + current_exercise_ind = ind; + } + } + + StateFileStatus::Read + }; + + file_buf.clear(); + file_buf.extend_from_slice(STATE_FILE_HEADER); + + let slf = Self { + current_exercise_ind, exercises, - n_done: 0, + n_done, final_message, - file_buf: Vec::with_capacity(2048), + state_file, + file_buf, official_exercises: !Path::new("info.toml").exists(), cmd_runner, vs_code: env::var_os("TERM_PROGRAM").is_some_and(|v| v == "vscode"), }; - let state_file_status = slf.update_from_file(); - Ok((slf, state_file_status)) } @@ -187,10 +194,8 @@ impl AppState { // - The fourth line is an empty line. // - All remaining lines are the names of done exercises. fn write(&mut self) -> Result<()> { - self.file_buf.clear(); + self.file_buf.truncate(STATE_FILE_HEADER.len()); - self.file_buf - .extend_from_slice(b"DON'T EDIT THIS FILE!\n\n"); self.file_buf .extend_from_slice(self.current_exercise().name.as_bytes()); self.file_buf.push(b'\n'); @@ -202,7 +207,14 @@ impl AppState { } } - fs::write(STATE_FILE_NAME, &self.file_buf) + self.state_file + .rewind() + .with_context(|| format!("Failed to rewind the state file {STATE_FILE_NAME}"))?; + self.state_file + .set_len(0) + .with_context(|| format!("Failed to truncate the state file {STATE_FILE_NAME}"))?; + self.state_file + .write_all(&self.file_buf) .with_context(|| format!("Failed to write the state file {STATE_FILE_NAME}"))?; Ok(()) @@ -440,11 +452,12 @@ impl AppState { } } +const BAD_INDEX_ERR: &str = "The current exercise index is higher than the number of exercises"; +const STATE_FILE_HEADER: &[u8] = b"DON'T EDIT THIS FILE!\n\n"; const RERUNNING_ALL_EXERCISES_MSG: &[u8] = b" All exercises seem to be done. Recompiling and running all exercises to make sure that all of them are actually done. "; - const FENISH_LINE: &str = "+----------------------------------------------------+ | You made it to the Fe-nish line! | +-------------------------- ------------------------+ @@ -490,6 +503,7 @@ mod tests { exercises: vec![dummy_exercise(), dummy_exercise(), dummy_exercise()], n_done: 0, final_message: String::new(), + state_file: tempfile::tempfile().unwrap(), file_buf: Vec::new(), official_exercises: true, cmd_runner: CmdRunner::build().unwrap(),