core API: move mkdir_existing to cache.rs

core/src/cache.rs

@@ -1,8 +1,11 @@
-use std::path::PathBuf;
-use std::io::Read;
+use std::fs;
 use std::fs::File;
+use std::io;
+use std::io::Read;
+use std::path::Path;
+use std::path::PathBuf;
 
-use util::{FileId, mkdir_existing};
+use util::FileId;
 use authentication::Credentials;
 
 #[derive(Clone)]
@@ -11,6 +14,16 @@ pub struct Cache {
     use_audio_cache: bool,
 }
 
+fn mkdir_existing(path: &Path) -> io::Result<()> {
+    fs::create_dir(path).or_else(|err| {
+        if err.kind() == io::ErrorKind::AlreadyExists {
+            Ok(())
+        } else {
+            Err(err)
+        }
+    })
+}
+
 impl Cache {
     pub fn new(location: PathBuf, use_audio_cache: bool) -> Cache {
         mkdir_existing(&location).unwrap();