Add the option to specify the system cache for credentials and volume files and adapt Cache to use two cache directories instead of one

core/src/cache.rs

@@ -11,7 +11,8 @@ use crate::volume::Volume;
 
 #[derive(Clone)]
 pub struct Cache {
-    root: PathBuf,
+    audio_root: PathBuf,
+    system_root: PathBuf,
     use_audio_cache: bool,
 }
 
@@ -26,12 +27,14 @@ fn mkdir_existing(path: &Path) -> io::Result<()> {
 }
 
 impl Cache {
-    pub fn new(location: PathBuf, use_audio_cache: bool) -> Cache {
-        mkdir_existing(&location).unwrap();
-        mkdir_existing(&location.join("files")).unwrap();
+    pub fn new(audio_location: PathBuf, system_location: PathBuf, use_audio_cache: bool) -> Cache {
+        mkdir_existing(&audio_location).unwrap();
+        mkdir_existing(&audio_location.join("files")).unwrap();
+        mkdir_existing(&system_location).unwrap();
 
         Cache {
-            root: location,
+            audio_root: audio_location,
+            system_root: system_location,
             use_audio_cache: use_audio_cache,
         }
     }
@@ -39,7 +42,7 @@ impl Cache {
 
 impl Cache {
     fn credentials_path(&self) -> PathBuf {
-        self.root.join("credentials.json")
+        self.system_root.join("credentials.json")
     }
 
     pub fn credentials(&self) -> Option<Credentials> {
@@ -53,10 +56,10 @@ impl Cache {
     }
 }
 
-// cache volume to root/volume
+// cache volume to system_root/volume
 impl Cache {
     fn volume_path(&self) -> PathBuf {
-        self.root.join("volume")
+        self.system_root.join("volume")
     }
 
     pub fn volume(&self) -> Option<u16> {
@@ -73,7 +76,7 @@ impl Cache {
 impl Cache {
     fn file_path(&self, file: FileId) -> PathBuf {
         let name = file.to_base16();
-        self.root.join("files").join(&name[0..2]).join(&name[2..])
+        self.audio_root.join("files").join(&name[0..2]).join(&name[2..])
     }
 
     pub fn file(&self, file: FileId) -> Option<File> {

src/main.rs

@@ -97,6 +97,11 @@ fn setup(args: &[String]) -> Setup {
         "cache",
         "Path to a directory where files will be cached.",
         "CACHE",
+    ).optopt(
+        "",
+        "system-cache",
+        "Path to a directory where system files (credentials, volume) will be cached. Can be different from cache option value",
+        "SYTEMCACHE",
     ).optflag("", "disable-audio-cache", "Disable caching of the audio data.")
         .reqopt("n", "name", "Device name", "NAME")
         .optopt("", "device-type", "Displayed device type", "DEVICE_TYPE")
@@ -244,9 +249,12 @@ fn setup(args: &[String]) -> Setup {
 
     let use_audio_cache = !matches.opt_present("disable-audio-cache");
 
-    let cache = matches
-        .opt_str("c")
-        .map(|cache_location| Cache::new(PathBuf::from(cache_location), use_audio_cache));
+    let cache_directory = matches.opt_str("c").unwrap_or(String::from(""))
+    let system_cache_directory = matches.opt_str("system-cache").unwrap_or(String::from(cache_directory))
+    let cache = Cache::new(
+        PathBuf::from(cache_directory),
+        PathBuf::from(system_cache_directory),
+        use_audio_cache));
 
     let initial_volume = matches
         .opt_str("initial-volume")