Allow specifying file start position (#445)

Like helix-term/src/commands.rs:3426:15

1 files changed, 40 insertions, 5 deletions

diff --git a/helix-term/src/args.rs b/helix-term/src/args.rs
index 40113db9..247d5b32 100644
--- a/helix-term/src/args.rs
+++ b/helix-term/src/args.rs
@@ -1,5 +1,6 @@
 use anyhow::{Error, Result};
-use std::path::PathBuf;
+use helix_core::Position;
+use std::path::{Path, PathBuf};
 
 #[derive(Default)]
 pub struct Args {
@@ -7,7 +8,7 @@ pub struct Args {
     pub display_version: bool,
     pub load_tutor: bool,
     pub verbosity: u64,
-    pub files: Vec<PathBuf>,
+    pub files: Vec<(PathBuf, Position)>,
 }
 
 impl Args {
@@ -41,15 +42,49 @@ impl Args {
                         }
                     }
                 }
-                arg => args.files.push(PathBuf::from(arg)),
+                arg => args.files.push(parse_file(arg)),
             }
         }
 
         // push the remaining args, if any to the files
-        for filename in iter {
-            args.files.push(PathBuf::from(filename));
+        for arg in iter {
+            args.files.push(parse_file(arg));
         }
 
         Ok(args)
     }
 }
+
+/// Parse arg into [`PathBuf`] and position.
+pub(crate) fn parse_file(s: &str) -> (PathBuf, Position) {
+    let def = || (PathBuf::from(s), Position::default());
+    if Path::new(s).exists() {
+        return def();
+    }
+    split_path_row_col(s)
+        .or_else(|| split_path_row(s))
+        .unwrap_or_else(def)
+}
+
+/// Split file.rs:10:2 into [`PathBuf`], row and col.
+///
+/// Does not validate if file.rs is a file or directory.
+fn split_path_row_col(s: &str) -> Option<(PathBuf, Position)> {
+    let mut s = s.rsplitn(3, ':');
+    let col: usize = s.next()?.parse().ok()?;
+    let row: usize = s.next()?.parse().ok()?;
+    let path = s.next()?.into();
+    let pos = Position::new(row.saturating_sub(1), col.saturating_sub(1));
+    Some((path, pos))
+}
+
+/// Split file.rs:10 into [`PathBuf`] and row.
+///
+/// Does not validate if file.rs is a file or directory.
+fn split_path_row(s: &str) -> Option<(PathBuf, Position)> {
+    let (row, path) = s.rsplit_once(':')?;
+    let row: usize = row.parse().ok()?;
+    let path = path.into();
+    let pos = Position::new(row.saturating_sub(1), 0);
+    Some((path, pos))
+}