Add 'from json'

crates/nu-path/src/tilde.rs

@@ -0,0 +1,85 @@
+use std::path::{Path, PathBuf};
+
+fn expand_tilde_with(path: impl AsRef<Path>, home: Option<PathBuf>) -> PathBuf {
+    let path = path.as_ref();
+
+    if !path.starts_with("~") {
+        return path.into();
+    }
+
+    match home {
+        None => path.into(),
+        Some(mut h) => {
+            if h == Path::new("/") {
+                // Corner case: `h` is a root directory;
+                // don't prepend extra `/`, just drop the tilde.
+                path.strip_prefix("~").unwrap_or(path).into()
+            } else {
+                if let Ok(p) = path.strip_prefix("~/") {
+                    h.push(p)
+                }
+                h
+            }
+        }
+    }
+}
+
+/// Expand tilde ("~") into a home directory if it is the first path component
+pub fn expand_tilde(path: impl AsRef<Path>) -> PathBuf {
+    // TODO: Extend this to work with "~user" style of home paths
+    expand_tilde_with(path, dirs_next::home_dir())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn check_expanded(s: &str) {
+        let home = Path::new("/home");
+        let buf = Some(PathBuf::from(home));
+        assert!(expand_tilde_with(Path::new(s), buf).starts_with(&home));
+
+        // Tests the special case in expand_tilde for "/" as home
+        let home = Path::new("/");
+        let buf = Some(PathBuf::from(home));
+        assert!(!expand_tilde_with(Path::new(s), buf).starts_with("//"));
+    }
+
+    fn check_not_expanded(s: &str) {
+        let home = PathBuf::from("/home");
+        let expanded = expand_tilde_with(Path::new(s), Some(home));
+        assert!(expanded == Path::new(s));
+    }
+
+    #[test]
+    fn string_with_tilde() {
+        check_expanded("~");
+    }
+
+    #[test]
+    fn string_with_tilde_forward_slash() {
+        check_expanded("~/test/");
+    }
+
+    #[test]
+    fn string_with_tilde_double_forward_slash() {
+        check_expanded("~//test/");
+    }
+
+    #[test]
+    fn does_not_expand_tilde_if_tilde_is_not_first_character() {
+        check_not_expanded("1~1");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn string_with_tilde_backslash() {
+        check_expanded("~\\test/test2/test3");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn string_with_double_tilde_backslash() {
+        check_expanded("~\\\\test\\test2/test3");
+    }
+}