From 3866035b636e6e8bd564966263500723a399dc4a Mon Sep 17 00:00:00 2001
From: Michael Davis <mcarsondavis@gmail.com>
Date: Sat, 17 Feb 2024 14:24:51 -0500
Subject: [PATCH] Add a core URI type

Co-authored-by: soqb <cb.setho@gmail.com>
---
 Cargo.lock            |   1 +
 helix-core/Cargo.toml |   1 +
 helix-core/src/lib.rs |   3 ++
 helix-core/src/uri.rs | 122 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 127 insertions(+)
 create mode 100644 helix-core/src/uri.rs

diff --git a/Cargo.lock b/Cargo.lock
index 2b8a25c85..69bce3f91 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1261,6 +1261,7 @@ dependencies = [
  "unicode-general-category",
  "unicode-segmentation",
  "unicode-width",
+ "url",
 ]
 
 [[package]]
diff --git a/helix-core/Cargo.toml b/helix-core/Cargo.toml
index 0b0dd7452..562d4295e 100644
--- a/helix-core/Cargo.toml
+++ b/helix-core/Cargo.toml
@@ -35,6 +35,7 @@ bitflags = "2.4"
 ahash = "0.8.6"
 hashbrown = { version = "0.14.3", features = ["raw"] }
 dunce = "1.0"
+url = "2.5.0"
 
 log = "0.4"
 serde = { version = "1.0", features = ["derive"] }
diff --git a/helix-core/src/lib.rs b/helix-core/src/lib.rs
index 94802eba9..be1fbc7bc 100644
--- a/helix-core/src/lib.rs
+++ b/helix-core/src/lib.rs
@@ -27,6 +27,7 @@ pub mod test;
 pub mod text_annotations;
 pub mod textobject;
 mod transaction;
+pub mod uri;
 pub mod wrap;
 
 pub mod unicode {
@@ -69,3 +70,5 @@ pub use diagnostic::Diagnostic;
 
 pub use line_ending::{LineEnding, NATIVE_LINE_ENDING};
 pub use transaction::{Assoc, Change, ChangeSet, Deletion, Operation, Transaction};
+
+pub use uri::Uri;
diff --git a/helix-core/src/uri.rs b/helix-core/src/uri.rs
new file mode 100644
index 000000000..4e03c58b1
--- /dev/null
+++ b/helix-core/src/uri.rs
@@ -0,0 +1,122 @@
+use std::path::{Path, PathBuf};
+
+/// A generic pointer to a file location.
+///
+/// Currently this type only supports paths to local files.
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[non_exhaustive]
+pub enum Uri {
+    File(PathBuf),
+}
+
+impl Uri {
+    // This clippy allow mirrors url::Url::from_file_path
+    #[allow(clippy::result_unit_err)]
+    pub fn to_url(&self) -> Result<url::Url, ()> {
+        match self {
+            Uri::File(path) => url::Url::from_file_path(path),
+        }
+    }
+
+    pub fn as_path(&self) -> Option<&Path> {
+        match self {
+            Self::File(path) => Some(path),
+        }
+    }
+
+    pub fn as_path_buf(self) -> Option<PathBuf> {
+        match self {
+            Self::File(path) => Some(path),
+        }
+    }
+}
+
+impl From<PathBuf> for Uri {
+    fn from(path: PathBuf) -> Self {
+        Self::File(path)
+    }
+}
+
+impl TryFrom<Uri> for PathBuf {
+    type Error = ();
+
+    fn try_from(uri: Uri) -> Result<Self, Self::Error> {
+        match uri {
+            Uri::File(path) => Ok(path),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct UrlConversionError {
+    source: url::Url,
+    kind: UrlConversionErrorKind,
+}
+
+#[derive(Debug)]
+pub enum UrlConversionErrorKind {
+    UnsupportedScheme,
+    UnableToConvert,
+}
+
+impl std::fmt::Display for UrlConversionError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self.kind {
+            UrlConversionErrorKind::UnsupportedScheme => {
+                write!(f, "unsupported scheme in URL: {}", self.source.scheme())
+            }
+            UrlConversionErrorKind::UnableToConvert => {
+                write!(f, "unable to convert URL to file path: {}", self.source)
+            }
+        }
+    }
+}
+
+impl std::error::Error for UrlConversionError {}
+
+fn convert_url_to_uri(url: &url::Url) -> Result<Uri, UrlConversionErrorKind> {
+    if url.scheme() == "file" {
+        url.to_file_path()
+            .map(|path| Uri::File(helix_stdx::path::normalize(path)))
+            .map_err(|_| UrlConversionErrorKind::UnableToConvert)
+    } else {
+        Err(UrlConversionErrorKind::UnsupportedScheme)
+    }
+}
+
+impl TryFrom<url::Url> for Uri {
+    type Error = UrlConversionError;
+
+    fn try_from(url: url::Url) -> Result<Self, Self::Error> {
+        convert_url_to_uri(&url).map_err(|kind| Self::Error { source: url, kind })
+    }
+}
+
+impl TryFrom<&url::Url> for Uri {
+    type Error = UrlConversionError;
+
+    fn try_from(url: &url::Url) -> Result<Self, Self::Error> {
+        convert_url_to_uri(url).map_err(|kind| Self::Error {
+            source: url.clone(),
+            kind,
+        })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use url::Url;
+
+    #[test]
+    fn unknown_scheme() {
+        let url = Url::parse("csharp:/metadata/foo/bar/Baz.cs").unwrap();
+        assert!(matches!(
+            Uri::try_from(url),
+            Err(UrlConversionError {
+                kind: UrlConversionErrorKind::UnsupportedScheme,
+                ..
+            })
+        ));
+    }
+}