refactor: replace icon loading with improved general image loading

src/desktop_file.rs

@@ -0,0 +1,74 @@
+use std::collections::HashMap;
+use std::fs::File;
+use std::io;
+use std::io::BufRead;
+use std::path::PathBuf;
+use walkdir::WalkDir;
+
+/// Gets directories that should contain `.desktop` files
+/// and exist on the filesystem.
+fn find_application_dirs() -> Vec<PathBuf> {
+    let mut dirs = vec![PathBuf::from("/usr/share/applications")];
+    let user_dir = dirs::data_local_dir();
+
+    if let Some(mut user_dir) = user_dir {
+        user_dir.push("applications");
+        dirs.push(user_dir);
+    }
+
+    dirs.into_iter().filter(|dir| dir.exists()).collect()
+}
+
+/// Attempts to locate a `.desktop` file for an app id
+/// (or app class).
+///
+/// A simple case-insensitive check is performed on filename == `app_id`.
+pub fn find_desktop_file(app_id: &str) -> Option<PathBuf> {
+    let dirs = find_application_dirs();
+
+    for dir in dirs {
+        let mut walker = WalkDir::new(dir).max_depth(5).into_iter();
+
+        let entry = walker.find(|entry| match entry {
+            Ok(entry) => {
+                let file_name = entry.file_name().to_string_lossy().to_lowercase();
+                let test_name = format!("{}.desktop", app_id.to_lowercase());
+                file_name == test_name
+            }
+            _ => false,
+        });
+
+        if let Some(Ok(entry)) = entry {
+            let path = entry.path().to_owned();
+            return Some(path);
+        }
+    }
+
+    None
+}
+
+/// Parses a desktop file into a flat hashmap of keys/values.
+fn parse_desktop_file(path: PathBuf) -> io::Result<HashMap<String, String>> {
+    let file = File::open(path)?;
+    let lines = io::BufReader::new(file).lines();
+
+    let mut map = HashMap::new();
+
+    for line in lines.flatten() {
+        if let Some((key, value)) = line.split_once('=') {
+            map.insert(key.to_string(), value.to_string());
+        }
+    }
+
+    Ok(map)
+}
+
+/// Attempts to get the icon name from the app's `.desktop` file.
+pub fn get_desktop_icon_name(app_id: &str) -> Option<String> {
+    find_desktop_file(app_id).and_then(|file| {
+        let map = parse_desktop_file(file);
+        map.map_or(None, |map| {
+            map.get("Icon").map(std::string::ToString::to_string)
+        })
+    })
+}