Detect rebase state

Author: forivall

src/todo_file/src/errors/io.rs

@@ -15,6 +15,9 @@ pub enum FileReadErrorCause {
 	/// Caused by a parse error
 	#[error(transparent)]
 	ParseError(#[from] ParseError),
+	/// Caused by the file path returning None for parent()
+	#[error("NoParentDir")]
+	NoParentDir(),
 }
 
 impl PartialEq for FileReadErrorCause {
@@ -24,6 +27,7 @@ impl PartialEq for FileReadErrorCause {
 		match (self, other) {
 			(Self::IoError(self_err), Self::IoError(other_err)) => self_err.kind() == other_err.kind(),
 			(Self::ParseError(self_err), Self::ParseError(other_err)) => self_err == other_err,
+			(Self::NoParentDir(), Self::NoParentDir()) => true,
 			_ => false,
 		}
 	}

src/todo_file/src/lib.rs

@@ -131,6 +131,7 @@ mod history;
 mod line;
 mod line_parser;
 mod search;
+mod state;
 #[cfg(not(tarpaulin_include))]
 pub mod testutil;
 mod todo_file_options;
@@ -143,13 +144,15 @@ use std::{
 	slice::Iter,
 };
 
+use state::detect_state;
 pub use version_track::Version;
 
 pub use self::{
 	action::Action,
 	edit_content::EditContext,
 	line::Line,
 	search::Search,
+	state::State,
 	todo_file_options::TodoFileOptions,
 };
 use self::{
@@ -171,6 +174,7 @@ pub struct TodoFile {
 	options: TodoFileOptions,
 	selected_line_index: usize,
 	version: Version,
+	state: State,
 }
 
 impl TodoFile {
@@ -188,6 +192,7 @@ impl TodoFile {
 			options,
 			selected_line_index: 0,
 			version: Version::new(),
+			state: State::Initial,
 		}
 	}
 
@@ -238,6 +243,7 @@ impl TodoFile {
 			})
 			.collect();
 		self.set_lines(lines?);
+		self.state = detect_state(&self.filepath)?;
 		Ok(())
 	}
 
@@ -457,6 +463,13 @@ impl TodoFile {
 		&self.version
 	}
 
+	/// Get the current state
+	#[must_use]
+	#[inline]
+	pub const fn state(&self) -> &State {
+		&self.state
+	}
+
 	/// Get the selected line.
 	#[must_use]
 	#[inline]

src/todo_file/src/state.rs

@@ -0,0 +1,63 @@
+use std::{
+	fmt::{Display, Formatter},
+	path::{Path, PathBuf},
+};
+
+use crate::errors::{FileReadErrorCause, IoError};
+
+/// Describes the state of rebase when editing the rebase todo file.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[allow(clippy::exhaustive_enums)]
+pub enum State {
+	/// Editing todo at start of a rebase.
+	Initial,
+	/// Editing todo in the middle of a rebase with --edit.
+	Edit,
+	/// Editing the todo file for git-revise
+	Revise,
+}
+
+pub(crate) fn detect_state(filepath: &Path) -> Result<State, IoError> {
+	if filepath.ends_with("git-revise-todo") {
+		return Ok(State::Revise);
+	}
+	if let Some(parent) = filepath.parent() {
+		if parent.join("stopped-sha").try_exists().map_err(|err| {
+			IoError::FileRead {
+				file: PathBuf::from(parent),
+				cause: FileReadErrorCause::from(err),
+			}
+		})? {
+			return Ok(State::Edit);
+		}
+	}
+	return Ok(State::Initial);
+}
+
+impl State {}
+
+impl Display for State {
+	#[inline]
+	fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+		write!(f, "{}", match *self {
+			Self::Initial => "initial",
+			Self::Edit => "edit",
+			Self::Revise => "revise",
+		})
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use rstest::rstest;
+
+	use super::*;
+
+	#[rstest]
+	#[case::edit(State::Initial, "initial")]
+	#[case::edit(State::Edit, "edit")]
+	#[case::edit(State::Revise, "revise")]
+	fn to_string(#[case] action: State, #[case] expected: &str) {
+		assert_eq!(format!("{action}"), expected);
+	}
+}