[Request] [+++ ] D8609: hg-core: add FindRoot operation to find repository root path

[acezar (Antoine Cezar)]

acezar created this revision.
Herald added a reviewer: hg-reviewers.
Herald added a subscriber: mercurial-patches.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D8609

AFFECTED FILES
  rust/hg-core/src/operations/find_root.rs
  rust/hg-core/src/operations/mod.rs

CHANGE DETAILS

diff --git a/rust/hg-core/src/operations/mod.rs b/rust/hg-core/src/operations/mod.rs
--- a/rust/hg-core/src/operations/mod.rs
+++ b/rust/hg-core/src/operations/mod.rs
@@ -1,3 +1,6 @@
+mod find_root;
+pub use find_root::{FindRoot, FindRootError, FindRootErrorKind};
+
 /// An interface for high-level hg operations.
 ///
 /// A distinction is made between operation and commands.
diff --git a/rust/hg-core/src/operations/find_root.rs b/rust/hg-core/src/operations/find_root.rs
new file mode 100644
--- /dev/null
+++ b/rust/hg-core/src/operations/find_root.rs
@@ -0,0 +1,128 @@
+use super::Operation;
+use std::fmt;
+use std::path::{Path, PathBuf};
+
+/// Kind of error encoutered by FindRoot
+#[derive(Debug, PartialEq)]
+pub enum FindRootErrorKind {
+    /// Root of the repository has not been found
+    RootNotFound,
+    /// The current directory does not exists or permissions are insufficient
+    /// to get access to it
+    GetCurrentDirError,
+}
+
+/// A FindRoot error
+#[derive(Debug, PartialEq)]
+pub struct FindRootError {
+    /// Kind of error encoutered by FindRoot
+    pub kind: FindRootErrorKind,
+
+    /// Curent directory used by FindRoot
+    ///
+    /// Can be none if std::env::current_dir returns std::io::Error
+    pub current_dir: Option<PathBuf>,
+}
+
+impl std::error::Error for FindRootError {}
+
+impl fmt::Display for FindRootError {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        unimplemented!()
+    }
+}
+
+/// Find the root of the repository
+/// by searching for a .hg directory in the current directory and its
+/// ancestors
+pub struct FindRoot<'a> {
+    current_dir: Option<&'a Path>,
+}
+
+impl<'a> FindRoot<'a> {
+    pub fn new() -> Self {
+        Self { current_dir: None }
+    }
+
+    pub fn new_from_path(current_dir: &'a Path) -> Self {
+        Self {
+            current_dir: Some(current_dir),
+        }
+    }
+}
+
+impl<'a> Operation<PathBuf> for FindRoot<'a> {
+    type Error = FindRootError;
+
+    fn run(&self) -> Result<PathBuf, Self::Error> {
+        let current_dir = match self.current_dir {
+            None => std::env::current_dir().or(Err(FindRootError {
+                kind: FindRootErrorKind::GetCurrentDirError,
+                current_dir: None,
+            }))?,
+            Some(path) => path.into(),
+        };
+
+        if current_dir.join(".hg").exists() {
+            return Ok(current_dir.into());
+        }
+        let mut anscestors = current_dir.ancestors();
+        while let Some(parent) = anscestors.next() {
+            if parent.join(".hg").exists() {
+                return Ok(parent.into());
+            }
+        }
+        Err(FindRootError {
+            kind: FindRootErrorKind::RootNotFound,
+            current_dir: Some(current_dir.to_path_buf()),
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs;
+    use tempfile;
+
+    #[test]
+    fn dot_hg_not_found() {
+        let tmp_dir = tempfile::tempdir().unwrap();
+        let path = tmp_dir.path();
+
+        let err = FindRoot::new_from_path(&path).run().unwrap_err();
+
+        assert_eq!(
+            err,
+            FindRootError {
+                kind: FindRootErrorKind::RootNotFound,
+                current_dir: Some(path.to_path_buf()),
+            }
+        )
+    }
+
+    #[test]
+    fn dot_hg_in_current_path() {
+        let tmp_dir = tempfile::tempdir().unwrap();
+        let root = tmp_dir.path();
+        fs::create_dir_all(root.join(".hg")).unwrap();
+
+        let result = FindRoot::new_from_path(&root).run().unwrap();
+
+        assert_eq!(result, root)
+    }
+
+    #[test]
+    fn dot_hg_in_parent() {
+        let tmp_dir = tempfile::tempdir().unwrap();
+        let root = tmp_dir.path();
+        fs::create_dir_all(root.join(".hg")).unwrap();
+
+        let result =
+            FindRoot::new_from_path(&root.join("some/nested/directory"))
+                .run()
+                .unwrap();
+
+        assert_eq!(result, root)
+    }
+} /* tests */



To: acezar, #hg-reviewers
Cc: mercurial-patches, mercurial-devel
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