Hash check if external process changed the content of the file

helix-view/Cargo.toml

@@ -50,6 +50,7 @@ toml = "0.8"
 log = "~0.4"
 
 parking_lot = "0.12.2"
+blake3 = { version = "1.5.1", features = ["mmap"] }
 
 
 [target.'cfg(windows)'.dependencies]

helix-view/src/document.rs

@@ -177,6 +177,10 @@ pub struct Document {
  // when document was used for most-recent-used buffer picker
  pub focused_at: std::time::Instant,
 
+ // Some(hash): the hash value of the document after the first read
+ // None: If the document doesn't exist in the filesystem
+ hash: Option<blake3::Hash>,
+
  pub readonly: bool,
 }
 
@@ -630,6 +634,7 @@ use url::Url;
 impl Document {
  pub fn from(
  text: Rope,
+ doc_hash: Option<blake3::Hash>,
  encoding_with_bom_info: Option<(&'static Encoding, bool)>,
  config: Arc<dyn DynAccess<Config>>,
  ) -> Self {
@@ -640,6 +645,7 @@ impl Document {
 
  Self {
  id: DocumentId::default(),
+ hash: doc_hash,
  path: None,
  encoding,
  has_bom,
@@ -674,7 +680,7 @@ impl Document {
  pub fn default(config: Arc<dyn DynAccess<Config>>) -> Self {
  let line_ending: LineEnding = config.load().default_line_ending.into();
  let text = Rope::from(line_ending.as_str());
- Self::from(text, None, config)
+ Self::from(text, None, None, config)
  }
 
  // TODO: async fn?
@@ -687,17 +693,23 @@ impl Document {
  config: Arc<dyn DynAccess<Config>>,
  ) -> Result<Self, Error> {
  // Open the file if it exists, otherwise assume it is a new file (and thus empty).
- let (rope, encoding, has_bom) = if path.exists() {
+ let (rope, encoding, has_bom, doc_hash) = if path.exists() {
  let mut file =
  std::fs::File::open(path).context(format!("unable to open {:?}", path))?;
- from_reader(&mut file, encoding)?
+
+ let mut hasher = blake3::Hasher::new();
+ hasher.update_mmap(path)?;
+
+ let (rope, encoding, has_bom) = from_reader(&mut file, encoding)?;
+
+ (rope, encoding, has_bom, Some(hasher.finalize()))
  } else {
  let line_ending: LineEnding = config.load().default_line_ending.into();
  let encoding = encoding.unwrap_or(encoding::UTF_8);
- (Rope::from(line_ending.as_str()), encoding, false)
+ (Rope::from(line_ending.as_str()), encoding, false, None)
  };
 
- let mut doc = Self::from(rope, Some((encoding, has_bom)), config);
+ let mut doc = Self::from(rope, doc_hash, Some((encoding, has_bom)), config);
 
  // set the path and try detecting the language
  doc.set_path(Some(path));
@@ -868,6 +880,7 @@ impl Document {
 
  let encoding_with_bom_info = (self.encoding, self.has_bom);
  let last_saved_time = self.last_saved_time;
+ let doc_hash = self.hash;
 
  // We encode the file according to the `Document`'s encoding.
  let future = async move {
@@ -888,7 +901,15 @@ impl Document {
  if let Ok(metadata) = fs::metadata(&path).await {
  if let Ok(mtime) = metadata.modified() {
  if last_saved_time < mtime {
- bail!("file modified by an external process, use :w! to overwrite");
+ if let Some(doc_hash) = doc_hash {
+ let mut hasher = blake3::Hasher::new();
+ hasher.update_mmap(&path)?;
+ let new_doc_hash = hasher.finalize();
+
+ if new_doc_hash != doc_hash {
+ bail!("file modified by an external process, use :w! to overwrite");
+ }
+ }
  }
  }
  }
@@ -2033,15 +2054,22 @@ mod test {
 
  use super::*;
 
- #[test]
- fn changeset_to_changes_ignore_line_endings() {
- use helix_lsp::{lsp, Client, OffsetEncoding};
- let text = Rope::from("hello\r\nworld");
- let mut doc = Document::from(
+ fn create_test_doc(content: &str) -> Document {
+  let text = Rope::from(content);
+ let hash = blake3::hash(content.as_bytes());
+
+ Document::from(
  text,
+ Some(hash),
  None,
  Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ )
+ }
+
+ #[test]
+ fn changeset_to_changes_ignore_line_endings() {
+ use helix_lsp::{lsp, Client, OffsetEncoding};
+ let mut doc = create_test_doc("hello\r\nworld");
  let view = ViewId::default();
  doc.set_selection(view, Selection::single(0, 0));
 
@@ -2074,12 +2102,7 @@ mod test {
  #[test]
  fn changeset_to_changes() {
  use helix_lsp::{lsp, Client, OffsetEncoding};
- let text = Rope::from("hello");
- let mut doc = Document::from(
- text,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let mut doc = create_test_doc("hello");
  let view = ViewId::default();
  doc.set_selection(view, Selection::single(5, 5));
 

helix-view/src/editor.rs

@@ -1600,6 +1600,7 @@ impl Editor {
  let (stdin, encoding, has_bom) = crate::document::read_to_string(&mut stdin(), None)?;
  let doc = Document::from(
  helix_core::Rope::default(),
+ None,
  Some((encoding, has_bom)),
  self.config.clone(),
  );

helix-view/src/gutter.rs

@@ -344,17 +344,22 @@ mod tests {
  use arc_swap::ArcSwap;
  use helix_core::Rope;
 
+ fn create_test_doc(content: &str) -> Document {
+ let rope = Rope::from_str(content);
+ let hash = blake3::hash(content.as_bytes());
+ Document::from(
+ rope,
+ Some(hash),
+ None,
+ Arc::new(ArcSwap::new(Arc::new(Config::default()))),
+ )
+ }
+
  #[test]
  fn test_default_gutter_widths() {
  let mut view = View::new(DocumentId::default(), GutterConfig::default());
  view.area = Rect::new(40, 40, 40, 40);
-
- let rope = Rope::from_str("abc\n\tdef");
- let doc = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc = create_test_doc("abc\n\tdef");
 
  assert_eq!(view.gutters.layout.len(), 5);
  assert_eq!(view.gutters.layout[0].width(&view, &doc), 1);
@@ -374,12 +379,7 @@ mod tests {
  let mut view = View::new(DocumentId::default(), gutters);
  view.area = Rect::new(40, 40, 40, 40);
 
- let rope = Rope::from_str("abc\n\tdef");
- let doc = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc = create_test_doc("abc\n\tdef");
 
  assert_eq!(view.gutters.layout.len(), 1);
  assert_eq!(view.gutters.layout[0].width(&view, &doc), 1);
@@ -392,12 +392,7 @@ mod tests {
  let mut view = View::new(DocumentId::default(), gutters);
  view.area = Rect::new(40, 40, 40, 40);
 
- let rope = Rope::from_str("abc\n\tdef");
- let doc = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc = create_test_doc("abc\n\tdef");
 
  assert_eq!(view.gutters.layout.len(), 2);
  assert_eq!(view.gutters.layout[0].width(&view, &doc), 1);
@@ -414,19 +409,8 @@ mod tests {
  let mut view = View::new(DocumentId::default(), gutters);
  view.area = Rect::new(40, 40, 40, 40);
 
- let rope = Rope::from_str("a\nb");
- let doc_short = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
-
- let rope = Rope::from_str("a\nb\nc\nd\ne\nf\ng\nh\ni\nj\nk\nl\nm\nn\no\np");
- let doc_long = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc_short = create_test_doc("a\nb");
+ let doc_long = create_test_doc("a\nb\nc\nd\ne\nf\ng\nh\ni\nj\nk\nl\nm\nn\no\np");
 
  assert_eq!(view.gutters.layout.len(), 2);
  assert_eq!(view.gutters.layout[1].width(&view, &doc_short), 1);

helix-view/src/view.rs

@@ -645,17 +645,22 @@ mod tests {
  use crate::document::Document;
  use crate::editor::{Config, GutterConfig, GutterLineNumbersConfig, GutterType};
 
- #[test]
- fn test_text_pos_at_screen_coords() {
- let mut view = View::new(DocumentId::default(), GutterConfig::default());
- view.area = Rect::new(40, 40, 40, 40);
- let rope = Rope::from_str("abc\n\tdef");
- let doc = Document::from(
+ fn create_test_doc(content: &str) -> Document {
+ let rope = Rope::from_str(content);
+ let hash = blake3::hash(content.as_bytes());
+ Document::from(
  rope,
+ Some(hash),
  None,
  Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ )
+ }
 
+ #[test]
+ fn test_text_pos_at_screen_coords() {
+ let mut view = View::new(DocumentId::default(), GutterConfig::default());
+ view.area = Rect::new(40, 40, 40, 40);
+ let doc = create_test_doc("abc\n\tdef");
  assert_eq!(
  view.text_pos_at_screen_coords(
  &doc,
@@ -823,12 +828,7 @@ mod tests {
  },
  );
  view.area = Rect::new(40, 40, 40, 40);
- let rope = Rope::from_str("abc\n\tdef");
- let doc = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc = create_test_doc("abc\n\tdef");
  assert_eq!(
  view.text_pos_at_screen_coords(
  &doc,
@@ -852,12 +852,7 @@ mod tests {
  },
  );
  view.area = Rect::new(40, 40, 40, 40);
- let rope = Rope::from_str("abc\n\tdef");
- let doc = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc = create_test_doc("abc\n\tdef");
  assert_eq!(
  view.text_pos_at_screen_coords(
  &doc,
@@ -875,12 +870,7 @@ mod tests {
  fn test_text_pos_at_screen_coords_cjk() {
  let mut view = View::new(DocumentId::default(), GutterConfig::default());
  view.area = Rect::new(40, 40, 40, 40);
- let rope = Rope::from_str("Hi! こんにちは皆さん");
- let doc = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc = create_test_doc("Hi! こんにちは皆さん");
 
  assert_eq!(
  view.text_pos_at_screen_coords(
@@ -958,12 +948,7 @@ mod tests {
  fn test_text_pos_at_screen_coords_graphemes() {
  let mut view = View::new(DocumentId::default(), GutterConfig::default());
  view.area = Rect::new(40, 40, 40, 40);
- let rope = Rope::from_str("Hèl̀l̀ò world!");
- let doc = Document::from(
- rope,
- None,
- Arc::new(ArcSwap::new(Arc::new(Config::default()))),
- );
+ let doc = create_test_doc("Hèl̀l̀ò world!");
 
  assert_eq!(
  view.text_pos_at_screen_coords(