refactor(bar): resolve env vars with pathext

This commit introduces a new PathExt trait with a fn replace_env which
can ensure all environemnt variables are loaded for a PathBuf.

As part of the initial rollout this is used in komorebi-bar to look up
environment variables for the configuration switcher widget.

resolve #1131

komorebi/src/core/mod.rs

@@ -25,6 +25,7 @@ pub use default_layout::DefaultLayout;
 pub use direction::Direction;
 pub use layout::Layout;
 pub use operation_direction::OperationDirection;
+pub use pathext::PathExt;
 pub use rect::Rect;
 
 pub mod animation;
@@ -37,6 +38,7 @@ pub mod default_layout;
 pub mod direction;
 pub mod layout;
 pub mod operation_direction;
+pub mod pathext;
 pub mod rect;
 
 #[derive(Clone, Debug, Serialize, Deserialize, Display, JsonSchema)]

komorebi/src/core/pathext.rs

@@ -0,0 +1,48 @@
+use std::env;
+use std::path::Component;
+use std::path::PathBuf;
+
+pub trait PathExt {
+    fn replace_env(&self) -> PathBuf;
+}
+
+impl PathExt for PathBuf {
+    fn replace_env(&self) -> PathBuf {
+        let mut result = PathBuf::new();
+
+        for component in self.components() {
+            match component {
+                Component::Normal(segment) => {
+                    // Check if it starts with `$` or `$Env:`
+                    if let Some(stripped_segment) = segment.to_string_lossy().strip_prefix('$') {
+                        let var_name = if let Some(env_name) = stripped_segment.strip_prefix("Env:")
+                        {
+                            // Extract the variable name after `$Env:`
+                            env_name
+                        } else if stripped_segment == "HOME" {
+                            // Special case for `$HOME`
+                            "USERPROFILE"
+                        } else {
+                            // Extract the variable name after `$`
+                            stripped_segment
+                        };
+
+                        if let Ok(value) = env::var(var_name) {
+                            result.push(&value); // Replace with the value
+                        } else {
+                            result.push(segment); // Keep as-is if variable is not found
+                        }
+                    } else {
+                        result.push(segment); // Keep as-is if not an environment variable
+                    }
+                }
+                _ => {
+                    // Add other components (e.g., root, parent) as-is
+                    result.push(component.as_os_str());
+                }
+            }
+        }
+
+        result
+    }
+}