Add native volume data saving support

src/main.rs

@@ -105,7 +105,7 @@ fn main() {
     )
     .unwrap();
 
-    let storage = store::Store {};
+    let mut storage = store::Store::new();
 
     let mut volume = storage.volume().map_or_else(
         || {

src/store.rs

@@ -1,13 +1,48 @@
+use std::{io::Seek, path::PathBuf};
+
+#[cfg(not(target_os = "emscripten"))]
+pub struct Store {
+    file: std::fs::File,
+}
+
+#[cfg(target_os = "emscripten")]
 pub struct Store;
 
 #[cfg(not(target_os = "emscripten"))]
 impl Store {
-    pub fn volume(&self) -> Option<u32> {
-        None
+    pub fn new () -> Self {
+        let path = Store::get_path();
+        let file = std::fs::OpenOptions::new()
+            .read(true)
+            .write(true)
+            .create(true)
+            .open(&path)
+            .unwrap();
+        Store { file }
     }
 
-    pub fn set_volume(&self, volume: u32) {
-        // Do nothing
+    fn get_path() -> PathBuf {
+        use std::env;
+        let mut path = env::current_exe().unwrap();
+        path.pop();
+        path.push("volume.txt");
+        path
+    }
+
+    pub fn volume(&mut self) -> Option<u32> {
+        use std::io::Read;
+
+        let mut buffer = String::new();
+        self.file.read_to_string(&mut buffer).unwrap();
+        buffer.trim().parse::<u32>().ok()
+    }
+
+    pub fn set_volume(&mut self, volume: u32) {
+        use std::io::Write;
+
+        self.file.set_len(0).unwrap();
+        self.file.seek(std::io::SeekFrom::Start(0)).unwrap();
+        write!(self.file, "{}", volume).unwrap();
     }
 }
 
@@ -19,6 +54,23 @@ extern "C" {
 
 #[cfg(target_os = "emscripten")]
 impl Store {
+    pub fn new () -> Self {
+        Store
+    }
+
+    pub fn volume(&self) -> Option<u32> {
+        // Use local storage to try and read volume
+        let script = "localStorage.getItem('volume')";
+        let response = Store::run_script_string(&script);
+        response.parse::<u32>().ok()
+    }
+
+    pub fn set_volume(&self, volume: u32) {
+        // Use local storage to set volume
+        let script = format!("localStorage.setItem('volume', '{}')", volume);
+        Store::run_script_string(&script);
+    }
+
     fn run_script(script: &str) {
         use std::ffi::CString;
 
@@ -38,17 +90,4 @@ impl Store {
             String::from(c_str.to_str().unwrap())
         }
     }
-
-    pub fn volume(&self) -> Option<u32> {
-        // Use local storage to try and read volume
-        let script = "localStorage.getItem('volume')";
-        let response = Store::run_script_string(&script);
-        response.parse::<u32>().ok()
-    }
-
-    pub fn set_volume(&self, volume: u32) {
-        // Use local storage to set volume
-        let script = format!("localStorage.setItem('volume', '{}')", volume);
-        Store::run_script_string(&script);
-    }
 }